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Analyzing the fulfillment of daylight and overheating requirements in residential and office buildings in Estonia
Abstract
Daylight and thermal comfort in cold climates have been proved crucial for the well-being of the building occupants. In this study, the reliability of the daylight requirements defined by the Estonian standard based on the mean daylight factor (DF) was evaluated with respect to the minimum DF requirements defined by the European standard method, EN 17037:2018 and IES LM-83-12, based on the spatial daylight autonomy (sDA) for office and residential buildings. The effect of window airing on overheating and also on the combination of overheating and daylighting was studied. Indoor comfort-based rules of thumb for the design of offices and residential rooms were suggested. A simulation-based methodology was applied to assess the daylighting and overheating performance in a single-window room considering different parameters. The results show that 30% of the combinations fulfill the mean DF requirement but not the sDA requirement. Moreover, there is an agreement between the Estonian standard EVS 894:2008/A2:2015 and European standard EN 17037:2018 for only 54% of room combinations. The addition of window airing increases the maximum window-to-wall ratio by 50% in residential rooms. The results suggest a synergistic formulation of daylighting and overheating requirements in new building regulations to make the combined fulfillment easier for the designers.
... The results of Useful Daylight Illuminance (UDI) aimed to identify the percentages of hours throughout a year during which the illuminance at the reference plane falls between 100 and 2,000 lx, as shown in Fig. 4. According to the proposal of NBR 15.575 [8] to meet uniformity criteria, there should be a minimum of 60 lx in the environment with a minimum fraction of 75 %. Therefore, for the original weather file 2020 and considering the surroundings, the results showed useful illuminance over 84 % and 85 % in the bedrooms, and 76 % in the living room/ kitchen. ...
... All the data mentioned were acquired through a unified electronic spreadsheet, which follows the previously described procedure. This spreadsheet provides a systematic and organized approach to calculate and verify the luminous performance of Low-Income Housing (HIS) in accordance with the guidelines outlined in NBR 15575:2022 [8]. This makes the analysis and evaluation process more efficient and accessible. ...
... Considering the Compact Low-Rise scenario, with weather data for 2050 (2041-2070) areas, there was a significant increase in sunlight exposure in all rooms compared to other LCZs, with results falling into the "intolerable" range in the bedrooms for both scenarios, with and without surroundings. Glare is often related to sunlight exposure [6], and according to Sepúlveda et al. [8], the provision of daylight in buildings is limited by the risk of overheating. This is an important issue to consider on building designs, especially on climates such as Belem, a city located in an extremely hot and humid (0A, ASHRAE 169-2013 [33]). ...
... Firstly to achieve a balance between daylight provision and overheating protection. Secondly to select the most suitable method to achieve this balance (Sepúlveda et al., 2020(Sepúlveda et al., , 2022. The application of Machine learning, which is a subdomain of Artificial Intelligence, has been widely used in building construction industry, especially in the field of architectural design and visualization (Baduge et al., 2022). ...
... In cold climates, there have been a lot of efforts not only proving the challenging task to find balance between daylight provision and thermal comfort during the warm season (Sepúlveda et al., 2020) , but also developing prediction formulas to balance these two performances during early design stages of dwellings (Sepúlveda et al., 2022). ...
... The independent variables or design parameters of the parametric model are: room orientation (ro), room width (rw), room depth (rd), window-to-wall ratio (WWR), visible transmittance (Tvis), g-value, and mean obstruction angle ( ̅ ). We used a building typology already used in previous investigation within the Estonian context (Sepúlveda et al., 2020). The total number of room combinations was 5120 and 40960 for minDF and DH simulations, respectively. ...
This paper presents a study about the prediction accuracy of daylight provision and overheating levels in dwellings when considering different methods (machine learning vs prediction formulas), training, and validation data sets. An existing high-rise building located in Tallinn, Estonia was considered to compare the best ML predictive method with novel prediction formulas. The quantification of daylight provision was conducted according to the European daylight standard EN 17037:2018 (based on minimum Daylight Factor (minDF)) and overheating level in terms of the degree-hour (DH) metric included in local regulations. The features included in the dataset are the minDF and DH values related to different combinations of design parameters: window-to-floor ratio, level of obstruction, g-value, and visible transmittance of the glazing system. Different training and validation data sets were obtained from a main data set of 5120 minDF values and 40960 DH values obtained through simulation with Radiance and EnergyPlus, respectively. For each combination of training and validation dataset, the accuracy of the ML model was quantified and compared with the accuracy of the prediction formulas. According to our results, the ML model could provide more accurate minDF/DH predictions than by using the prediction formulas for the same design parameters. However, the amount of room combinations needed to train the machine-learning model is larger than for the calibration of the prediction formulas. The paper discuss in detail the method to use in practice, depending on time and accuracy concerns.
... Jung et al. [35] and Rey et al. [36] used the MOOGA to address various building variables to minimize the energy use, life cycle assessment, and cost of a residential building in South Korea and Canada, respectively. Finally, Sepúlveda et al. [37] and Zhang et al. [38] used the MOOGA to address WWR, window properties (U-value, SHGC, and Visible Transmittance), and exterior shading, to improve the thermal and daylight performance of a residential building in Estonia [37] and a new school building in China [38]. ...
... Jung et al. [35] and Rey et al. [36] used the MOOGA to address various building variables to minimize the energy use, life cycle assessment, and cost of a residential building in South Korea and Canada, respectively. Finally, Sepúlveda et al. [37] and Zhang et al. [38] used the MOOGA to address WWR, window properties (U-value, SHGC, and Visible Transmittance), and exterior shading, to improve the thermal and daylight performance of a residential building in Estonia [37] and a new school building in China [38]. ...
... 1) There is a lack of studies [38][39][40][41] about how to renovate existing school buildings to achieve multiple building performances, especially for students in Quebec or similar cold climates in general, compared to studies on archetype residential and office buildings [26][27][28][29][30][31][32][33][34][35][36][37]. 2) Most previous studies focused on finding the optimal design for two objectives, i.e., indoor thermal comfort with visual comfort or energy use, using less than five decision variables. ...
This paper aims to develop long-term adaptation strategies for the existing Canadian school buildings under extreme current and future climates using a developed methodology based on global and local sensitivity analysis and Multi-Objective Optimization Genetic Algorithm. The calibrated simulation model based on indoor and outdoor measured temperature for a school of interest is used to evaluate the optimization strategies. This paper aims to search for the optimum school building design under three simultaneous conflicting objective functions: (1) the minimization of overheating hours to less than 40 h as required by Building Bulletin BB101 building code by using passive mitigation measures, (2) the minimization of heating energy use to less than 15 kW/m 2 according to passive house requirements and thus the reduction of greenhouse gas emissions, and (3) the minimization of artificial lighting energy use to less than the current lighting energy use by maximization of daylighting usage without exceeding acceptable glare index in classrooms. Ten building design variables are selected, which could generate approximately 300,000 solutions. The developed methodology reduced the numbers to 14,400 solutions and found seven Pareto solutions that comply with the three objectives and their constraints. High energy-efficient building envelope, appropriate window-wall ratio and window type, natural ventilation during the day, and night cooling can play a key role in achieving the objectives under current weather conditions. An additional cool roof and external overhang will be needed in the medium-term future climate, and an additional movable screen shading will be needed in the long-term future climate.
... Jung et al. [35] and Rey et al. [36] used the MOOGA to address various building variables to minimize the energy use, life cycle assessment, and cost of a residential building in South Korea and Canada, respectively. Finally, Sepúlveda et al. [37] and Zhang et al. [38] used the MOOGA to address WWR, window properties (U-value, SHGC, and Visible Transmittance), and exterior shading, to improve the thermal and daylight performance of a residential building in Estonia [37] and a new school building in China [38]. ...
... Jung et al. [35] and Rey et al. [36] used the MOOGA to address various building variables to minimize the energy use, life cycle assessment, and cost of a residential building in South Korea and Canada, respectively. Finally, Sepúlveda et al. [37] and Zhang et al. [38] used the MOOGA to address WWR, window properties (U-value, SHGC, and Visible Transmittance), and exterior shading, to improve the thermal and daylight performance of a residential building in Estonia [37] and a new school building in China [38]. ...
... 1) There is a lack of studies [38][39][40][41] about how to renovate existing school buildings to achieve multiple building performances, especially for students in Quebec or similar cold climates in general, compared to studies on archetype residential and office buildings [26][27][28][29][30][31][32][33][34][35][36][37]. 2) Most previous studies focused on finding the optimal design for two objectives, i.e., indoor thermal comfort with visual comfort or energy use, using less than five decision variables. ...
... Recently, the European standard EN 17037:2018 defined four main representative aspects of daylight in buildings: sunlight exposure or solar access, view out, daylight provision, and glare protection [12]. Regarding the EN 17037:2018, most studies focus on the quantitative assessment of visual comfort and the development of efficient methods to assess the different daylight aspects in existing and new buildings [13][14][15][16][17][18][19]. For instance, Sepúlveda et al. discovered that the Estonian daylight standard based on the mean DF metric has limited reliability in properly predicting the daylight potentials of building interiors [13]. ...
... Regarding the EN 17037:2018, most studies focus on the quantitative assessment of visual comfort and the development of efficient methods to assess the different daylight aspects in existing and new buildings [13][14][15][16][17][18][19]. For instance, Sepúlveda et al. discovered that the Estonian daylight standard based on the mean DF metric has limited reliability in properly predicting the daylight potentials of building interiors [13]. In fact, Bournas found that the vast majority of 10888 evaluated residential rooms did not fulfill DF-based criterion proposed by the EN 17037:2018, which is much stricter than the current Swedish daylight criterion [14]. ...
... De Luca and Sepúlveda [17] found that the EN 17037:2018 is more conservative than the Estonian standard EVS 894 for daylight provision and solar access [20]. Nevertheless, the coexistence of different daylight standards in a same country could confuse the designer because the consideration of different aspects of daylight, metrics, and requirements could change completely the final building design as demonstrated in previous investigations for the Estonian [13,21] and Slovenian context [22]. Moreover, within the EN 17037:2018, there are no recommendations to adapt minimum requirements depending on the building type or cultural context, which was highlighted in a recent research [23]. ...
There is a lack of methods and studies that evaluate the validity of daylight standards such as the EN 17037:2018 in specific local contexts as cold climates. Moreover, the probable adaptation of the EN 17037:2018 by European countries motivated the aim of this investigation: to study the applicability of the EN 17037:2018 in a certain cultural context through the comparison of the subjective perception of Estonian office users with the quantitative assessment defined by the EN 17037:2018, including the four aspects: solar access, view out, daylight provision, and glare protection. In order to study the applicability of the EN 17037:2018 for Estonian office spaces, we used a mixed-method approach based on semi-structured interviews, measurements, and daylight simulations. Poor view out is related with high obstruction levels of urban features, despite the presence of multiple layers in the view. The level of recommendations for good view out in Estonian office rooms might be lower than the thresholds recommended by the EN 17037:2018. Except during winter months, direct sunlight exposure is not appreciated in Estonian office spaces since it is strongly related to glare discomfort caused by sun in the field of view and on computer screens. Working under daylight conditions during the whole year and having an easy-to-use interior shading systems to block the direct sunlight is very valuable for Estonian office users. For daylight and glare protection, there is a good agreement between qualitative evaluations given by office users and quantitative assessments proposed by the EN 17037:2018.
... Although solar irradiance is effective in building indoor air temperature, visual comfort is greatly influenced by it [37] and therefore both thermal and visual effects were considered in some research works simultaneously [38][39][40][41][42][43]. In hot seasons, the plants displaced to locate in front of the window to block the solar thermal gain from entering the room. ...
... The lettuce seedling were planted in the system and the lettuce production was approximately 8 kg m −2 per month. The water used in this hydroponic lettuce farming system was about 0.08 m 3 , which was much lower (about 0.096 m 3 kg −1 ) than in field farming [40]. Moreover, the volume of collected rainwater during the experiment period was 0.04 m 3 . ...
Nearly buildings consume 40% of the world’s total energy. With the constant push to reduce energy consumption in buildings, a novel nature-based system is proposed for use in buildings. This novel solution is a controllable system that could control solar heat gain, solar illuminance while enhance urban green space and produce local organic vegetables with low water consumption. To assess the system performance, a paired comparison was made in two similar rooms, one with the novel system installed outside its window and the second as the control treatment. The experimental results show that the maximum recorded indoor air temperature and solar thermal gain reductions due to the system installation were 2.9 °C and 61%, respectively. However, it could also decrease useful daylight illuminance up to 22.9%. Therefore, to achieve a stable optimum thermo-visual comfort, the room indoor temperature reduction and useful daylight illuminance were optimized using NSGA-II (Elitist Non-dominated Sorting Genetic Algorithm). The novel system and building nexus provides optimum thermo-visual comfort and approximately 8 kg m−2 per month organic vegetables for building residents. Finally, we proposed a performance flowchart for the transient control of the passive cooling and the natural daylight illumination of the room.
... DF is widely used because it is a simple metric to use through formulas or simulations that require small computational time (Reinhart and Lo Verso, 2010). However, DF predictions have limited reliability because they do not take into account building orientation, latitude and local climate (Sepúlveda et al., 2020). During the last decades, annual climate based daylight simulations (CBDS) have been developed to help researchers and practitioners obtaining more reliable predictions (Reinhart et al., 2006). ...
... At each iteration a specific algorithm of the parametric model selects the DF values of the half of the sensor points closer to the window to assess if the target of 2.1 % is achieved. The second requirement of a minimum DF of 0.7 % across 95 % of the reference plane is not considered because existing studies proved that if the first requirement is fulfilled, then the second is satisfied as well (Sepúlveda et al., 2020). ...
... Window wall ratio (WWR), which is the ratio of the window area to the window-wall area is a key factor that influences the amount of daylight entering into the spaces, and therefore visual comfort conditions and lighting energy load. It is generally suggested to create WWR around 30% for providing good daylight and high energy performance [7,8,9]. Glazing type is also one of the significant variable in controlling daylight availability because of the light transmittance. ...
... Shading is another critical daylighting design consideration due to the harmful drawbacks of direct sunlight on the comfort conditions as well as total energy loads for especially highly-glazed buildings. The researches show that fixed shading devices are the most convenient option for preventing discomfort due to the glare [6], and perform more effective on decreasing total energy consumption regarding cooling loads rather than solar control glazing for hot climates [8]. On the other hand, the movable shading strategies can lead to desirable solutions in terms of both minimization of energy demand for lighting and cooling, and maximization of daylight utilization besides thermal comfort in especially heating-dominated climate [13]. ...
Promoting the daylight performance that allows to provide visual comfort conditions by minimizing lighting energy consumption is possible with making a balance of window size, glazing type and shading strategy, which are the major design parameters of the daylighting system. Particularly, in high-rise buildings, where large openings enabling higher daylight availability and view out are preferred, the daylighting system becomes a crucial design consideration in terms of ensuring occupants’ visual comfort and improving lighting energy efficiency. This study aims to identify a proper daylighting design solution with regard to window area, glazing type and shading strategy for a high-rise residential building located in Istanbul considering visual comfort and lighting energy efficiency. The dynamic simulations are carried out by DIVA for Rhino version 4.1.0.12. The results are evaluated with the Daylight Autonomy (DA) to detect daylight availability in the space and Daylight Glare Probability (DGP) to describe the visual comfort conditions related to glare. Furthermore, the lighting energy consumption of each alternative is also analysed to determine the proper daylighting solution. The results have revealed that a proper daylighting solution providing visual comfort by improving lighting energy-efficiency can be determined by the evaluation of the daylight performance both qualitatively and quantitatively.
... However, it can be deduced from the results whether one configuration or another can affect heating or cooling (Košir et al., 2018). Conversely, thermal evaluations of solar control strategies can suggest their light performance, which implies a synergistic formulation between both requirements so that combined compliance is easier for designers (Sepúlveda et al., 2020). Hence, it is necessary to find suitable design variables that can balance daylighting and energy performance, achieving potential energy savings by decreasing lighting and thermal energy requirements. ...
The implementation of the solar protections laid out in the regulations and certification systems decreases cooling demands, although it has an uncontrolled and even unforeseen effect on daylighting. Achieving a balance between both requirements is a challenge for facade design, energy behavior, and lighting performance since restricting solar radiation contributions decreases daylight's contribution. This research aims to define a methodology that allows, in the early design stage, the evaluation of solar protection solutions that consider the optimal performance of daylight using annual dynamic indicators while maintaining adequate energy-saving levels. For this purpose, cooling energy consumption and dynamic indicators have been considered as the primary indicators, namely Spatial daylight autonomy (sDA), Annual Sunlight Exposure (ASE), and useful daylight illuminance (UDI) with variations of the Modified Solar Factor (MSF). Thermal and light performance assessments were made using energy modeling for two types of solar protection. The case study is a school classroom located in the city of Talca, in central Chile, considering window-to-wall ratios (WWR) of 40 %, 50 %, and 60 %. The premise's thermal and light behavior were obtained with both types of solar protection. The sDA and UDI results allowed making an approximation of optimal solutions, however, the ASE values in all cases, were classified as unsuitable for classroom use. The analysis suggests that better limit values for both requirements are obtained by organizing the results by WWR instead of by the MSF that each solution identifies. This methodology compared solar protection options at an early design stage, reaching recommended light performance levels and energy savings of 70 % or more, for the two types of solar protection. It is concluded that to achieve minimum acceptable daylighting levels, in balance with cooling energy consumption, it is necessary to consider annual dynamic assessments with sDA and UDI as relevant indicators.
... Today, great attention is paid to the shape of buildings [6,7], their orientation [8,9], the mutual distance between buildings and building density [10,11], vegetation use [12,13], maximization of daylight use [14,15], the use of modern construction materials [16,17], and shading devices, which will be chronologically (from 1998 to 2024) analyzed below. In [18], the effects of passive cooling using window overhangs for a building located in Shiraz (Iran) were investigated experimentally and theoretically. ...
The global scientific community is intensively promoting energy-plus buildings. Following the leading world trends, this paper presents a new energy-plus building concept-elevational earth-sheltered buildings with three different types of horizontal overhang photovoltaic-integrated panels: wooden support columns covered with clay tiles, steel pipes as support columns covered with sheet steel, and concrete support columns with concrete coverage. In this instance, the specific multi-numerical case study building model for the city of Kragujevac (located in central Serbia with favorable climatic conditions) was performed over 7 months (from 1 October to 30 April), taking into account the soil temperature, the effects of solar shading, the performance of the heating system-a ground source heat pump-and the characteristics of the artificial and automatic lighting control system. The simulation results show that the optimal depth of a horizontal overhang (energy-plus status) depends on the occupant's habits, in addition to meteorological conditions. The presented methodology can be used for any other location, both in Europe and the world.
... Nesse encadeamento é possível analisar a intensidade da iluminação natural em edifícios por meio de diferentes métodos, sendo o mais utilizado o fator médio de luz do dia (DF), oriundo do Reino Unido e usado principalmente para aferir a luz natural em condições nubladas. Além disso, a análise do desempenho dinâmico da iluminação natural em edifícios também se torna uma quantidade a ser avaliada, para a qual as técnicas de autonomia da luz do dia (DA) e autonomia espacial da luz do dia (sDA) podem ser aplicadas (Sepúlveda et al., 2020). ...
A iluminação natural, quando presente nos ambientes internos das edificações, em concordância com as necessidades de cada local, traz benefícios à saúde humana. Por outro lado, quando está em discordância com o espaço, pode ter um efeito negativo, causando problemas como ofuscamento, reflexos, sombras e interferências térmicas. Nesse sentido, esta pesquisa visa simular, interpretar e comparar como a luz natural e seu desempenho lumínico, com base na métrica sDA (Spatial Daylight Autonomy), se comportam em um ambiente residencial nas cidades de Santa Maria/RS (zona bioclimática 2), Cuiabá/MT (zona bioclimática 7) e Fortaleza/CE (zona bioclimática 8). Foi utilizado o software DesignBuilder, tendo em vista os critérios adotados pelo RTQ-R para o processamento analítico mais detalhado dos dados. Os resultados obtidos nas simulações indicam que os índices de luz natural de melhor desempenho nos modelos analisados na faixa de 300 lux alcançaram 99,52% e foram posicionados na fachada oeste da cidade de Cuiabá/MT, enquanto os índices de pior desempenho atingiram 57,49% e foram simulados na fachada sul da cidade de Santa Maria/RS. Isso se deve ao fato de que, no Hemisfério Sul, as fachadas norte e oeste recebem mais luz solar direta do que as fachadas sul e leste.
... Using a more holistic approach, some authors have intended to conduct integrated research on window performance that takes both thermal and daylighting concerns into account [28][29][30]. Ochoa et al., (2012) investigated the necessity to balance thermal and visual comfort in a reference office located in Amsterdam, the Netherlands. The results yielded that to achieve the illuminance requirements set by the building codes, WWRs need to be considered larger than when improvement of façade thermal performance is the only criterion: 70% for the north and 60% for the south, east, and west. ...
This work aims to propose a simplified decision tool for the design of side-lit spaces that accounts for the impacts of climate and surroundings. The framework was developed using a smart optimization algorithm NSGA-III in combination with CatBoost ensemble machine learning technique and simulation. WWRs and overhang depths were optimized to maximize daylight penetration, minimize glare risk and reduce energy demand in different climates, orientations, space proportions, and surrounding obstruction angles. Besides, optimal solutions were used to determine the range of attainable targets for daylight, glare, and energy metrics in each climate, which can be used as requirements of national codes and standards. For example, for WDR = 3:2 and an OA of 20, energy demand varied between 260 and 266 kWh/m2, ASE remained at 40–50%, and sDA was reported 100% for south-oriented cases in Tehran. A sensitivity analysis was also performed to provide insights into how various design parameters affected daylight and energy performance in architectural spaces. The results revealed that daylight availability metrics were highly sensitive to the Window-to-Wall Ratio (WWR), while glare metrics were primarily affected by obstruction angle. Energy consumption was mainly influenced by room depth, WWR, window orientation, and obstruction angle. Notably, these parameters ranked similarly across all considered climates, albeit with varying degrees of significance. Results were presented in the form of guide charts that offer a practical tool for designing buildings in highly obstructed contexts and enable non-programmer architects and designers to make informed decisions.
... In addition, prefabricated systems can be designed with passive solar features to improve not only energy performance, but also the provision of daylight 19 . Optimization of natural light penetration, may improve indoor visual comfort and reduce the need for artificial lighting 20 . This is supported by the prefabricated systems' ability for transformation, which facilitates the incorporation of architectural components such as skylights, clerestory windows and light shelves 21 . ...
Housing prefabrication emerged as an energy and cost-saving solution, which can also be linked to the reduction of environmental impacts, as well as to the development of green construction practices. In the first part of this study, a comprehensive literature review of the prefabricated assembly methods and their inherent potential, in terms of both design and construction are presented. Design strategies that incorporate the integration of environmental systems are also considered. A classification and taxonomy of archetypes is included, based on key design principles pertaining to environmental design. Based on the conclusions drawn from the assessment of these considerations, this paper revisits the realm of design and construction techniques used in energy efficient and environmentally compatible prefabricated housing unit in a Cypriot context. Cost-saving strategies are proposed, as well as architectural design and fabrication recommendations. Consequently, the research aims to contribute to existing literature by drawing results from an actual demonstration project in Cyprus. It goes on to outline considerations affecting the front end of the design and construction processes based on criteria for efficient prefabrication and modular construction. Findings are then related to simulations for energy and daylighting performance supplemented by a techno-economic analysis, aiming to demonstrate the viability of this enterprise. In this way it is hoped that stakeholders considering the adoption of this approach to design and construction may make better informed and more appropriate decisions.
... Sepulveda et al. (2020) published a recent case study that simulated the overheating risk in a Spanish residential unit. The study applied the Spanish regulations and focused on reducing the overheating risk by manipulating the window-to-wall ratio and night ventilation [32]. In Sweden, Tettey and Gustavsson (2020) explored the climate change implication on a renovated housing unit [33]. ...
With the ongoing significance of overheating calculations in the residential building sector, building codes such as the European Energy Performance of Building Directive (EPBD) are essential for harmonizing the indicators and performance thresholds. This paper investigates Europe's overheating calculation methods, indicators, and thresholds and evaluates their ability to address climate change and heat events. e study aims to identify the suitability of existing overheating calculation methods and propose recommendations for the EPBD. The study results provide a cross-sectional overview of twenty-six European countries. The most influential overheating calculation criteria are listed the best approaches are ranked. The paper provides a thorough comparative assessment and recommendations to align current calculations with climate-sensitive metrics. The results suggest a framework and key performance indicators that are comfort-based, multi-zonal, and time-integrated to calculate overheating and modify the EU's next building energy efficiency regulations. The results can help policymakers and building professionals to develop the next overheating calculation framework and approach for the future development of climate-proof and resilient residential buildings.
... The first concept was the Passive House standard: a solution to build cheaply, easily and energy-efficiently. The research done in objects constructed in this standard showed imperfections such as overheating in summers and inadequate air quality from mechanical ventilation [16,17,18,19]. The sick building syndrome has been widely discussed [20,21,22,23,24,25]. ...
The building sector consumes one-third of global final energy and emits nearly 40% of total CO2 emission. To decrease those numbers, it is necessary to design sustainable buildings, which have low heat and cooling demand. The Passive House standard was designed to meet these requirements however, some imperfections were observed. Therefore, a new approach the “be 2226” standard was put forward. This paper presents major architectural differences of those concepts and discusses their advantages and disadvantages. The main purpose is to develop guidelines how to design energy-efficient passive architecture. The Author used own mixed research method that included literature studies, analyses of technical documentation, in situ examinations, own measurements, and infrared tests. The comparison of two passive standards established strong, proven solutions, as well as incompatibilities and flows of each standard. The research main findings are that all buildings should be built in the passive manner and it would be beneficial to implement mixed standard. The main conclusion is that architectural creation has a great impact on passive solutions in buildings.
... (2) View out; (3) Exposure to sunlight; and (4) Protection from glare. Previous works focused mainly on the implementation of the "Indoor daylight provision" and "Protection from glare" criteria (Jones, 2019;Šprah and Košir, 2019;Paule, 2019;Sepúlveda et al., 2020). Instead, the proposed paper focuses on the "View out" and "Exposure to sunlight" sections; namely, it introduces a computational approach to facilitate compliance assessment at early design stages. ...
... The daylight model integrated the three-dimensional and parametric models and materials described in section 4. [82,83], the sDA metric was chosen because existing studies proved the limited reliability of the two standard requirements based on the Daylight Factor metric in predicting adequate daylight provision in the Estonian climate [84]. sDA makes use of dynamic climate based daylight simulations and is based on the concept of daylight autonomy, developed for the daylight metrics DA and cDA [55]. ...
Exterior static shading devices of buildings, if correctly designed, can control sunlight and daylight to reduce glare while guaranteeing interiors' natural illumination and connection to the outside which increase occupants' physiological and psychological wellbeing. The shadings can also control solar radiation, which has strong influence on buildings' energy use. Most of the existing research investigated the effects of static shadings on either energy use, or daylight availability and distribution or glare using single-view assessments. A number of studies integrated the analysis of two or the three performances. Very few analyzed the effects on view out. This research investigates through simulations the potential of exterior static shadings in reducing disturbing glare, and the effects on daylight provision, view out, and energy use in two classrooms in the northern city of Tallinn, Estonia. The novelty resides in the integration of the four performances analysis through a multi-objective optimization workflow, allowed by a spatial glare assessment method. Results showed that, for the building type and location, static shadings reduced visual discomfort by up to 89.8% while reduced primary energy use by up to 29.1% and provided adequate levels of daylight and view out. The most performative shading types and detailed results are presented and discussed.
... It has been proved that human health deteriorates with long exposure to artificial lighting, whereas daylight can relieve discomfort and stress [20,21]. However, strong daylight may cause discomforts such as solar glare [23] and overheat [24,25]. A building envelope plays a major role in daylight transmission. ...
A translucent concrete panel (TCP) is a novel construction material for building envelopes. It combines light conduits, such as optical fibers (OFs), and lightweight high-strength concrete, enabling it to transmit light and carry the external load. A set of TCPs was cast using OFs with a large diameter (17.8 mm). The compressive strength was 39.6 N/mm², which is qualified to carry the external load as the structural components. The thermal conductivity of the TCP was 0.2114 W/(m·K), indicating excellent thermal insulation performance compared to traditional building envelopes, such as glass curtain walls (GCW) and masonry facades. To investigate the energy consumption of a TCP, a one-roomed office building was modeled numerically. Three cities were selected to analyze the monetary cost and energy consumption of various building envelopes. These building envelopes were made of a masonry wall, GCW, and TCP. The simulation results revealed that the model with a TCP envelope had the lowest electricity consumption, monetary cost, and payback period. Moreover, it was more energy efficient in Stockholm and Nanjing than in Singapore. The novel TCP is applicable in building envelopes and other areas where light transmission and load-bearing are required.
... It is, therefore, imperative that the regulations define sufficient minimal criteria for the daylight provision. In a study by Ko et al. and Sepúlveda et al. [11] it was found that the Estonian daylight standard had limited reliability in predicting daylight, and there was a strong disagreement between the national and European standard. In 2019, the European standard concerning criteria for daylight in buildings (EN 17037) was implemented as a Norwegian standard. ...
Window design affects the overall performance of a building. It is important to include window design during the initial stages of a project since it influences the performance of daylight and thermal comfort as well as the energy demand for heating and cooling. The Norwegian building code facilitates two alternative methods for achieving a sufficient daylight, and only guidelines for adequate indoor thermal comfort. In this study, a typical Norwegian residential building was modeled to investigate whether the criteria and methods facilitate consistent and good performance through different scenario changes and furthermore, how the national regulations compare to European standards. A better insulated and more air-tight building has usually a lower annual heating demand, with only a marginal decrease in the daylight performance when the window design is unchanged. A more air-tight construction increases the risk of overheating, even in cold climates. This study confirms that a revision of the window design improves the overall performance of a building, which highlights the importance of proper window design. The pursuit of lower energy demand should not be at the expense of indoor thermal comfort considering the anticipated future weather conditions. This study indicates that criteria for thermal comfort and daylight, if clearly defined, can affect the energy demand for heating and cooling, as well as the indoor climate positively, and should be taken into account at the national level. A comparison between the national regulations and the European standards was made, and this study found that the results are not consistent.
... It has been proved that human health deteriorates with long exposure to artificial lighting, whereas daylight can relieve discomfort and stress [20,21]. However, strong daylight may cause discomforts such as solar glare [23] and overheat [24,25]. A building envelope plays a major role in daylight transmission. ...
... 17037 Compliance Indoor daylight provision; (2) View out; (3) Exposure to sunlight; and (4) Protection from glare. Previous works focused mainly on the implementation of the "Indoor daylight provision" and "Protection from glare" criteria [2]- [5]. Instead, the proposed paper focuses on the "View out" and "Exposure to sunlight" sections; namely, it introduces a computational approach to facilitate compliance assessment at early design stages. ...
The paper presents open-source computational workflows for assessing the "Exposure to sunlight" and "View out" criteria as defined in the European standard EN 17037 "Daylight in Buildings", issued by the European Committee for Standardization. In addition to these factors, the standard document also addresses daylight provision and protection from glare, both of which fall out of the scope of this paper. The purpose of the standard is stated as 'encouraging building designers to assess and ensure successfully daylit spaces'. The standard document proposes verification methods for performing such assessments, albeit without recommending a simulation procedure for computing the aforementioned criteria. The workflows proposed in this paper are arguably the first attempt to standardize these assessment methods using de-facto open-source standard technologies currently used in practice. The approach of this work is twofold: establish that the compliance check can be systematically performed on a 3D model by a novel simulation tool developed by the authors; and highlighting the additional assumptions that need to be implemented to build a robust and unambiguous tool within existing open-source frameworks.
... Among the several daylight metrics available in ClimateStudio, sDA300/50% was used as introduced by LM-83-12 ( Figure 5). Although the current Estonian daylight standard requires daylight assessments through DF, sDA was used because existing literature proved that DF is not reliable to predict daylight levels in Estonia (Sepúlveda et al. 2020). The main Radiance parameters used in the simulations were: -ab 6 -lw 0.01 -ad 1. ...
Daylight and solar access influence positively building occupants` wellbeing and students' learning performance. However, an excess of sunlight can harm the visual comfort of occupants through disturbing glare effects. This study investigated, through multi-objective optimization, the potential of static shading devices to reduce glare and to guarantee daylight provision in a university building. The results showed that the reduction of disturbing glare was up to more than twice the reduced daylight, which nevertheless, was provided in adequate levels. View out and energy performance were also analyzed. Detailed results of optimal shading types and classrooms layout indications are presented.
... In general, higher WWRs can increase the quantity of daylight in the buildings, while it Energies 2020, 13, 5836 3 of 16 can cause unwanted heat gains. According to the study by Abel et al., WWRs should be properly designed in the early design stage to prevent overheating in buildings [32]. In addition to their study, the function of WWRs can be varied by the shading design. ...
In Saudi Arabia, residential buildings are one of the major contributors to total energy consumption. Even though there are abundant natural resources, it is somewhat difficult to apply them to building designs, as design variables, due to slow progress and private issues in Saudi Arabia. Thus, the present study demonstrated the development of sustainable residential building design by examining the daylighting and energy performance with design variables. Focusing on the daylighting system, the design variables were chosen, including window-to-wall ratios (WWR), external shading devices, and types of glazing. The illuminance level by these design variables in a building was evaluated by using daylight metrics, such as spatial daylight autonomy and annual sunlight exposure. Moreover, the building energy consumption with these design variables was analyzed by using energy simulation. As a result, the daylighting was improved with the increase in WWRs and the tinted double glazing, while these design options can cause overheating in a residential building. Among types of glazing, the double pane windows with a low-E coating showed better energy performance. Based on the results, it is necessary to find the proper design variables that can balance the daylighting and energy performance in residential buildings in hot climates.
In tropical climates, the thermal performance of air-conditioned commercial building envelopes, particularly offices, is commonly assessed using the Overall Thermal Transfer Value (OTTV).
Designing office buildings in these regions requires meticulous attention to achieve the optimum thermal-daylight balance, which often has conflicting characteristics. This study aims to enhance
the thermal-daylight performance optimization process for open-plan office building envelopes in tropical climates, with Kuala Lumpur as a specific case study. The methodology involves para
metric thermal and daylight simulations, incorporating an extensive global sensitivity analysis (GSA) based on the Monte Carlo method. Next, the most critical design parameters affecting
daylight provision are identified and used to develop a prediction formula for daylight provision assessment. Finally, the exploration further examines the impact of dominant parameters on energy consumption across diverse urban densities. The results pinpointed the Shading Coefficient (SC 1) and Window-to-Wall Ratio (WWR) as pivotal factors affecting heat gain. At the same
time, obstruction angle (Theta), WWR, and Visible Transmittance (Tvis) significantly influence daylight provision. Furthermore, the developed daylight prediction formula consists of a fast method that can be coupled with OTTV to evaluate and optimise the thermal-daylight performance in the early design stage of office buildings. Moreover, the study reveals potential energy
savings of up to 8 %, 4.83 %, and 4 % in very low, medium, and very high urban densities, respectively. These insights and the daylight prediction formula provide valuable tools for optimising building envelope thermal-daylight performance during the early stages of architectural design, offering practical guidance for both practitioners and researchers.
There is a lack of facade design methods for early design stages to balance thermal comfort and daylight provision that consider the obstruction angle as an independent variable without using modeling and simulations. This paper aims to develop easy-to use solar radiation-based prediction method for the design of office building facades (i.e., design parameters: room size, window-to-floor ratio, and glazing thermal/optical properties) located in urban canyons to balance daylight provision according to the European standard EN 17037:2018 and thermal comfort through specific cooling capacity. We used a simulation-based methodology that includes correlation analyses between building performance metrics and design parameters, the development of design workflows, accuracy analysis, and validation through the application of the workflows to a new development office building facades located in Tallinn, Estonia. The validation showed that the mean percentage of right/conservative predictions of thermal comfort classes is 98.8% whereas for daylight provision, it is higher than 75.6%. The use of the proposed prediction method can help designers to work more efficiently during early design stages and to obtain optimal performative solutions in much shorter time: window sizing in 73152 room combinations in 80 seconds.
This paper proposes a ML-based optimization design workflow based on obstruction angles for the optimization of building facades (i.e. g-value and window width). The optimization output consists of the optimal clustering of windows in order to ensure a desired level of daylight provision according to method 2 defined in the EN17307:2018 (i.e. based on Spatial Daylight Autonomy: sDA) and to not exceed a maximum level of specific cooling capacity (SCC). The independent variables or design parameters of the parametric model are: room orientation/dimensions, window dimensions, and obstruction angle (θ). The ML prediction models were trained and tested with reliable simulation results using validate softwares. The total number of room combinations is 61440 for sDA and SCC simulations. The development of reliable (90% of right predictions) ML predictive models based on decision tree technique were calibrated. The optimal clustering of windows was done first by floors and secondly by the designer’s need to homogenize the external facade with similar glazing properties and window sizes, having impact on the annual heating consumption. The proposed method help designers to make accurate and faster design decisions during early design stages and renovation plans.
This investigation proposes a 7-steps multi-performance method for urban densification and applies it to an existig urban block located in Tallinn, Estonia. This design workflow has two main features lacked by previous methods: (1) flexible, easy-to-use and fast, minimizing the dependence on time-consuming simulations with need of daylight and dynamic thermal modeling/simulation; (2) performance-driven differentiation of the FAR metric (i.e. room area, daylight, SA, and overheating protection levels). It was used to find the optimal densification strategy depending on 7 different design criteria defined as trade-offs between: floor-area ratio, daylight provision, solar access, and outdoor thermal comfort.
Purpose: This study aims to evaluate a full year’s indoor illuminance distribution and visual comfort conditions of a daylight public basic school located in a hot-dry region by means of an experimental simulation and a subjective response survey. Design/Methodology/Approach: A mixed method technique was adopted. Climate-based daylighting modelling metrics for assessing daylight availability and quality were employed to assess percentage of time over the year where internationally acceptable ranges are reached (UDI 300lux−500lux; DA300lux; ASE1000, 250 h of 3%). Mean values and standard deviations of questionnaire responses under different fenestrations and weather conditions were analysed at the scale of a single classroom and groups of classrooms. Findings: UDI and DA values for the rainy season and the dry season for all fenestrations fell below the benchmark values from the simulation (UDI 300lux−500lux; DA300lux). This was corroborated by the results from the subjective survey. F3 which was a casement window and had the highest WWR recorded its highest mean UDI and DA values as 43.01 lux and 38.40 lux respectively for the dry season. Similar results were recorded for F1 which recorded the lowest mean UDI (42.81 lux) and DA (42.59 lux) values. Research Limitation: This study involved primarily three fenestration types. A further inquisition in other distinct climatic regions will provide more information on the impact of the choice of fenestration and visual comfort conditions of other public basic schools. Practical Implication: The study highlights the poor lighting conditions in this school over a long-term assessment. A thorough assessment of annual lighting conditions to highlight conditions is required in daylight public schools. A guideline for fenestration type selection for these schools will be required based on the climatic conditions. Social Implication: The findings of this study are essential for designers, policy makers and other stakeholder institutions to fully understand the effect of the choice of fenestration and climatic factors on a properly daylight educational space and examine the potential of energy and cost savings. Originality/Value: This study explored lighting quality from the perspective of simulated lighting quantities and subjective assessments from participants within the simulated classrooms on a long-term basis, a very rare type of study in Ghana. The study adds on to the body of literature in daylighting studies in the country.
This paper proposes a novel multi-criteria method for building massing based on energy performance and solar access allowed to the surrounding buildings (Mixed Solar Envelope (MSE) method). We used a single thermal zone simulation-based methodology to validate the method. We applied the MSE method in a generic urban zone located in Tallinn, Estonia. Determining the building form, the designer can prioritize energy performance and/or solar access for each studied neighbor's room, as well as the importance between studied rooms. The method allowed to generate building masses (MSEs) capable of saving up to 73% and 67% of the total annual energy consumption in office and residential rooms with window-to-wall-ratio of 80%. As a tool to negotiate between different rooms, the total annual energy savings was between 56-80% when considering a pure energy-based criterion. The annual energy savings was between 26-30% while maximizing the annual number of sun hours when considering solar access-based criteria.
Population growth and urbanisation trends bring many consequences related to the increase in global energy consumption, CO2 emissions and a decrease in arable land per person. High‑rises have been one of the inevitable buildings of metropoles to provide extra floor space since the early examples in the 19th century. Therefore, optimisation of high-rise buildings has been the focus of researchers because of significant performance enhancement, mainly in energy consumption and generation. Based on the facts of the 21st century, optimising high-rise buildings for multiple vital resources (such as energy, food, and water) is necessary for a sustainable future.
This research suggests “self-sufficient high-rise buildings” that can generate and efficiently consume vital resources in addition to dense habitation for sustainable living in metropoles. The complexity of self-sufficient high-rise building optimisation is more challenging than optimising regular high-rises that have not been addressed in the literature. The main challenge behind the research is the integration of multiple performance aspects of self-sufficiency related to the vital resources of human beings (energy, food, and water) and consideration of large numbers of design parameters related to these multiple performance aspects. Therefore, the dissertation presents a framework for performance optimisation of self-sufficient high-rise buildings using artificial intelligence focusing on the conceptual phase of the design process. The output of this dissertation supports decision-makers to suggest well-performing high-rise buildings involving the aspects of self sufficiency in a reasonable timeframe.
According to the results of research, building windows, due to direct contact with solar radiation, impose significant heat on the interior spaces and make them the main factor in increasing the cooling load in building. In this article, using Design Builder and Energy Plus software, the shape of the window is examined in three modes in terms of receiving radiation on the north and south fronts. In the next step, the best shape of the window is selected and compared with the initial state in terms of cooling load and energy consumption. The results show that the square window has poor performance compared to other modes. So that the horizontal and vertical windows in the southern and northern facades, respectively, have transmitted 59.86 and 29.19 KWh less radiation to the space during a year. This reduction in the case study is equivalent to 4870 kWh for a one-year period.
The increase in global population, which negatively affects energy consumption, CO2 emissions, and arable land, necessitates designing sustainable habitation alternatives. Self-sufficient high-rise buildings, which integrate (electricity) generation and efficient usage of resources with dense habitation, can be a sustainable solution for future urbanisation. This paper focuses on transforming Europoint Towers in Rotterdam into self-sufficient buildings considering energy consumption and food production (lettuce crops) using artificial intelligence. Design parameters consist of the number of farming floors, shape, and the properties of the proposed façade skin that includes shading devices. Nine thousand samples are collected from various floor levels to predict self-sufficiency criteria using artificial neural networks (ANN). Optimisation problems with 117 decision variables are formulated using 45 ANN models that have very high prediction accuracies. 13 optimisation algorithms are used for an in-detail investigation of self-sufficiency at the building scale, and potential sufficiency at the neighbourhood scale. Results indicate that 100% and 43.7% self-sufficiencies could be reached for lettuce crops and electricity, respectively, for three buildings with 1800 residents. At the neighbourhood scale, lettuce production could be sufficient for 27,000 people with a decrease of self-sufficiency in terms of energy use of up to 11.6%. Consequently, this paper discusses the potentials and the improvements for self-sufficient high-rise buildings.
Indoor comfort in buildings has a critical impact on occupants’ health and cognitive performance. The fulfillment of daylight provision and overheating risk requirements can be challenging. This paper proposes a coupled method based on prediction formulas that can be used to assess daylight provision and overheating risk in buildings. In addition, this method can be used for the design of interior floor plan and window sizing in order to rooms fulfill simultaneously both performances. The considered daylight provision requirements are based on the minimum Daylight Factor (minDF) defined by the European standard EN17037, and the overheating risk requirements are based on the degree-hour (DH) metric adopted by the Estonian regulation. The minimum window-to-wall ratio (minWWR) to fulfill minDF-based requirements and maximum g-value to fulfill at the same time DH-based requirements for any room design can be calculated or represented graphically. The prediction accuracy in terms of relative RMSE is up to 0.20 for minDF and DH values. By using this approach, designers can minimize the number of design iterations during early stages, as well as the required computational time required by daylight and energy simulations. Furthermore, the proposed coupled method based on minDF and DH prediction formulas has big potential to help architects and designers to achieve the combined fulfillment between daylight provision and overheating protection during early stages of the design process within the Estonian context. Finally, the authors recommend the proposed coupled method to regulation makers for future building standards and regulations.
The aim of this paper is to propose an optimization workflow to help designers to choose efficient shading control strategies at North latitudes. These strategies are based on one single control variable with an activation threshold that is optimized to achieve a suitable overall performance. Interior roller fabrics with openness factor of 3% and high diffuse transmittance operated by illuminance-based controls have big potential to achieve satisfactory overall performance in educational buildings in Estonia. Optimal illuminance threshold values depend on room orientation and surrounding obstructions.
Two significant design strategies for mitigating building energy consumption are daylight redirection and solar energy harvesting. Effective daylighting implementation enhances the amount of useful natural light within a space and offsets the need for electric lighting. Solar energy harvesting systems can mitigate energy costs from mechanical systems by managing incoming thermal loads or capturing solar energy that can be used to supplement thermal systems in the building. While there are many available façade-based technologies that can perform daylighting or solar thermal energy harvesting, there remains a limitation in available systems that can perform both of them simultaneously. This paper, describes the design and experimental demonstration of a Liquid Filled Prismatic Louver (LFPL) system, which combines both energy-saving strategies. The LFPL system was installed in a south-facing room in New York City and evaluated for indoor daylight penetration and potential for thermal energy harvesting. Daylight redirection is achieved through the prismatic louver geometry and proper orientation, whereas thermal energy harvesting is achieved through IR absorption from the liquid (e.g., water) within the prisms. Daylighting performance was evaluated by illuminance measurements at key locations within the space, whereas thermal harvesting performance was evaluated through temperature measurements and thermal imaging analysis. We show that the LFPL system, with all prismatic elements oriented at the same angle, achieve a 2-fold and 8-fold enhancement in daylight redirection to the ceiling, for prism orientations of 10° and 20°, respectively. We also demonstrate the system’s capability to adjust to specific lighting needs, within the space, through the dynamic individual orientation of prismatic elements; thus, achieving a concentrated ceiling illuminance enhancement of ~100 times and ~200 times at 2.5 and 4.3 m away from the window sill, providing workplane illuminance enhancement of 6 and 2 times more than in the case of the control room with regular windows. Furthermore, we show a reduction of potential heating loads at locations close to the window from the combination of infrared absorption in the water volume and the redirection of the incoming solar radiation, leading to a reduction of the workplane temperature by an average of 7–10 °C.
Daylighting is a parallel universe to Architecture, where architects benefit greatly from daylight prediction techniques, which have witnessed a paradigm shift from simple methods to more sophisticated computational simulation tools. Still, such accumulating complexities made many designers disinclined to integrate what they consider difficult methods into their practices, even hindered the casual use of simulation tools, due to the lack of essential knowledge, among other complications. Herein, this research aims to provide a comprehensive review of over 100 years of growing fundamental directions to predict the amount of daylight inside buildings, with a particular focus on tracing sky models, weather datasets, building geometry and daylight calculation methods, which drove the progress of performance metrics and simulation tools, considering detailed descriptions of 50 prevalent simulation tools. This historical review is conducted with the architects’ nature in mind to underline existing knowledge gaps in the research domain and reveal future perspectives. Another implication of this research is to remove ambiguity of unfamiliar terms and technicalities, helping practitioners, especially young architects, of different backgrounds and expertise to grasp the essential daylight-related topics, guiding their decisions on suitable tools to use in building design.
Light is necessary for vision; it enables us to sense and perceive our surroundings and in many direct and indirect ways, via eye and skin, affects our physiological and psychological health. The use of light in built environments has comfort, behavioural, economic and environmental consequences. Daylight has many particular benefits including excellent visual performance, permitting good eyesight, effective entrainment of the circadian system as well as a number of acute non-image forming effects and the important role of vitamin D production. Some human responses to daylight seem to be well defined whilst others require more research to be adequately understood. This paper presents an overview of current knowledge on how the characteristics of daylight play a role in fulfilling these and other functions often better than electric lighting as conventionally delivered.
The building façade not only provides the aesthetic signature of a building, but also important functions, such as daylight provision, glare protection, solar gain management and visual contact with the outside, which make the building usable and energy efficient. These functions often oppose each other, so the selection and design of façade systems and their control for a certain building application should depend on those functions that the designer wants to promote to the detriment of the other functions. In the context of the H2020 RenoZEB project, this paper presents a workflow for the conceptual planning of façade systems as applied to building retrofitting. The proposed workflow consists of analysing the space from the point of view of the functions of its façade. In a first step, the analysis of the case study leads to the definition of the design requirements, i.e. the relevance of the different façade functions and their priorities. The second step involves the selection of a suitable fenestration system and control strategy for the retrofit solution. In this step, an optimization process for the control strategy is proposed based on state-of-the-art thermal and daylighting simulations. In a third step, the annual performance of the retrofit solution is evaluated in order to check if the requirements are fulfilled. The proposed workflow is illustrated with a case study, in which the automation strategy of a retrofitted façade system is optimized for two different applications: a residential and an office building in Bilbao (Spain).
Daylight is of interest in architecture for two reasons: On one hand it is appreciated and requested to make the interiors of buildings pleasant and comfortable and to save energy for electric lighting and heating. On the other hand excessive direct solar exposure can cause occupant discomfort and harm the energy efficiency of buildings causing overheating during the warm season. In Estonia, a daylight ordinance establishes the minimum average Daylight Factor for residential buildings and an energy efficiency ordinance sets the maximum acceptable degree hours of overheating. The two requirements are potentially conflicting. The recent architectural trend in Estonia is to use very large windows in residential building design. Even in the Estonian heating dominated climate this causes overheating issues that lead to the previously mentioned regulations. This paper explores the relationship of opening ratios, daylighting and overheating potential analyzing 7812 design variants taking into account room, windows and external wall sizes, presence of shading or balconies and different types of ventilation. It is shown that the overheating potential can be contained and both requirements can be satisfied only using measures such as shading and ventilation.
Residential architecture constitutes one of the largest market segments in the construction sector. However, the attention that it is given in the field of daylight performance simulation is surprisingly low. This poses the question of whether existing daylighting metrics are well suited for residential design. Findings from 79 references are summarized, and a critical review of current climate-based daylighting metrics in the context of residential architecture is provided. It is found that existing workflows often overlook relevant aspects of daylight in residential spaces, such as diurnal and seasonal availability of daylight and access to direct sunlight. Hence, a concept for a new climate-based, annual evaluation framework that overcomes these shortcomings, called the residential daylight score, is introduced.
Multi-functional and advanced building envelopes can provide step-change improvements in the energy efficiency and economic value of new and refurbished buildings, while improving the wellbeing of building occupants.
The scope of this work was to analyze the performance of different window configurations on indoor climate and to identify the most effective strategies for improvements.
This work investigated different strategies to improve thermal comfort in a case study by optimizing the responsiveness of the building skin by applying control strategies for cooling with natural ventilation and the use of automatically controlled shading devices.
This case study of a single-family house is located in the mountainous region of Norway. The results focus on summer temperatures and overheating, and daylight levels in the different rooms. Four rooms were found to be most critical for overheating during summer and the results confirm large number of hours with operative temperatures above 27˚C in these zones. The results show that several rooms show high temperatures in summer, even with sun protection glass (type 2 and 3) and external screen (type 4 and 5). Cooling by natural ventilation by opening windows shows good results and proved to be effective in providing good summer comfort conditions. This has implications for the design and especially the choice of glazing and shading in residential buildings.
This paper addresses the potential benefit achievable via model-based, predictive control of the AC system in overheated buildings with large glazed façades.
A sick building in Italy (and more specifically a protractedly and intensely sunlit office on the south-exposed, fully-glazed façade) was selected as case study.
It was monitored over a week in December. The sensor network mapped the indoor climatic conditions, the surface temperature distribution on the glazed façade and the thermodynamic parameters of the air inlet from the 3-speed fan coil unit serving the room (originally in manual mode).
The MPC relied on a grey-box model of the room’s thermal dynamics, built on a short-term monitoring dataset (4-day-lasting collection in November) and tuned during the first day of testing. Its ergonomic and energetic performance was assessed on the two days of maximum and minimum solar radiation.
Considerably high operative temperature persisted all over the period of observation. However, while in free running the room reached peak values of almost 28 °C, during the operation of the MPC the setpoint value of 24 °C was never exceeded by more than 2 °C. Indeed, the offset stayed within ±0.5 °C for the 95.8% of the time on the sunnier day and for the 60.8% on the cloudier day, while the PMV remained within the ±0.5 range for the 85% and the 80% respectively. No local discomfort from vertical gradients or drafts occurred.
Furthermore, the energy consumptions were remarkably contained since the fan operated at minimum speed for nearly the 80% of time.
On fully-glazed building façades perforated solar screens (PSS) are often used as an outer skin in order to reduce energy consumption and to solve issues such as visual appearance. However, not only must PSS control solar radiation but they must also provide adequate daylight levels, thus requiring a balanced solution. Currently, daylighting simulation software enables us to perform efficient daylight analysis of spaces with PSS. Notwithstanding this, current energy simulation software such as EnergyPlus cannot deal well with such geometry directly, making the thermal evaluation of PSS an infeasible task. This paper presents a methodology for achieving an integrated analysis of daylighting and energy consumption of spaces with PSS during the design stage. Such methodology provides daylight analysis through DIVA, and thermal analysis through EnergyPlus via DIVA/Grasshopper/Archsim. The aim is to optimise the dual performance of a balanced PSS solution through controlling its perforation percentage, matrix and shape, by using the orthogonal arrays (DOA) statistical method. DOA method is efficient in reducing the number of simulations derived from the combination of the aforementioned variables, and in identifying the optimal PSS configuration. In comparison to a non-optimised façade located in Seville, Spain, the predicted optimal PSS achieved a 50% increase in the actual daylit area and a 55% reduction in the total energy demand.
As a part of the building design process, Estonian building code requires standardized dynamic hourly simulations to verify the building’s compliance to the summer thermal comfort requirements. In this study, we analysed this overheating assessment method for free-running residential buildings, by comparing the simulation results with measured data. Simulation models with different thermal zoning levels were studied: single-zone models, multi-zone apartment models and multi-zone whole building models. We analysed and quantified the effects of modelling detail and thermal zoning on indoor temperature and overheating estimation on the basis of five apartment buildings. Based on the results, a method, using indoor temperature measurements and outdoor climate data, to assess overheating risk has been proposed, as a relatively simple and inexpensive method for pre-defining the need for dynamic simulations.
In South Korea, the evaluation criteria for installing shading devices are defined by regulations, but the standards of design methods are not clearly established. The installation of shading devices has become mandatory for some public buildings due to revised regulations. Therefore, a design of horizontal shading device is required, and indoor environmental problems which may occur due to their installation should also be taken into consideration. This research aimed to propose a design which takes into account the energy consumption which may occur if the horizontal shading device is installed and suggests an improved design method of horizontal shading devices when they are installed. Consequently, it was confirmed that as the protrusion of the horizontal shading device becomes longer, the incoming daylight is reduced and the indoor intensity of illumination becomes lower, and thus more lighting energy may be consumed in a room where the shading device is installed than in the one where it is not. Therefore, annual energy consumption was calculated by applying the lighting control and it was found that the total energy consumption decreased by the reduction of air-conditioning and fans and lighting energy consumption.
Purpose
The purpose of this paper is to propose a scientific method to evaluate possible urban layouts of a test building integrating building regulations, natural light standard and energy requirements to achieve nearly zero-energy buildings in Estonia. The integration of building regulations, energy requirements and natural light standards is crucial to evaluate the incidence of the surrounding environment when analyzing the energy performance of buildings.
Design/methodology/approach
The paper investigates the variations of the energy consumption of a model building with different orientations and variable urban surroundings configurations for the latitude of Tallinn. The different urban configurations are due to combinations of the different building requirements of fire safety, daylighting and insolation hours that in Estonia affect the layout of residential districts, thus influencing significantly the potential consumption of buildings. Different layouts of surrounding buildings have been chosen all guaranteeing at different degrees the fulfillment of the building requirements for the test building and energy simulations have been run to find the urban layouts that guarantee best performances.
Findings
The outcomes show that the test building interior temperatures and energy performances vary significantly in the different urban planning configurations and for the different orientations, underlining that is strongly recommended to run always energy simulation of building considering their surrounding environment. The conclusions show the principles to integrate the building regulations to achieve nearly zero-energy districts that significantly can improve life quality in the urban environment.
Originality/value
The paper analyze the energy efficiency of buildings with different features and orientations simulating their possible urban environment layouts given by building regulations, and not isolated or as built in “an open field” like most of the existing literature in the field.
Purpose
The purpose of this paper is to constitute an efficient way to improve energy efficiency and occupants comfort in buildings through reduction of direct solar heat gains by exterior shading devices. The shadings orientation and layout depends on the building location and façade orientation, and influence consequently the windows layout. It is still debated which type of window layout is preferable for a specific building location and façade orientation.
Design/methodology/approach
The paper presents a method to determine the most efficient windows’ layout, horizontal or vertical, for shading devices optimization by mean of integrating energy simulations and computational design. A parametric model has been built by visual programming language to simulate, iterate and compare the results.
Findings
The research shows the most efficient layouts of windows to be shaded for three latitudes and locations, and the 16 cardinal directions, to be used by architects and designers. The results show a significant prevalence of the horizontal window type on the south façades but also on the east and west orientations for all the three locations, while the rules of thumb would suggest the vertical layout for the sunrise and sunset façades.
Originality/value
The task of designing exterior shading devices presents two main issues: the shading period selection and the method of calculating its size and shape. The present research uses the innovative method Shaderade that existing literature demonstrates superior comparing other more dated like the section method and the solar vectors one.
The main objectives of this research it to find out if modern daylight assessment and design methods can be useful for urban residential planning in Poland. The study gives a chance to describe and appraise modern daylight design techniques. The other purpose is to illustrate how daylight knowledge could be used as an incentive to rethink the way urban environments are created. Although daylight design is acknowledged in literature and case studies as a tool for fostering residents’ well-being, daylight design techniques are not common practice in Poland. A review of current Polish building and lighting regulations regarding daylight is presented. The results of the two pilot questionnaires show a lack of daylight training among future architects and urban specialists. The first survey carried out among 54 students illustrates the importance of daylight as a natural resource which is essential in sustainable approaches to urban planning. It also highlights the belief that daylight and electric light projects should be holistically integrated in the implementation of the city lighting plans. The results of the second pilot study show a growing demand for better daylight education and an urgent need for revision of the existing recommendations in Poland.
Appropriate window solutions are decisive for the design of ‘nearly zero-energy’ buildings with healthy and comfortable indoor environment. This paper focuses on the relationship between size, orientation and glazing properties of façade windows for different side-lit room geometries in Danish ‘nearly zero-energy’ houses. The effect of these parameters on space heating demand, daylighting and thermal environment is evaluated by means of EnergyPlus and DAYSIM and presented in charts illustrating how combinations of design parameters with minimum space heating demand can be selected within a solution space defined by targets for daylighting and thermal comfort. In contrast with existing guidelines, the results show an upper limit for energy savings and utilisation of solar gains in south-oriented rooms. Instead, low U-values are needed in both north- and south oriented rooms before large window areas lead to reductions in space heating demand. Furthermore, windows in south-oriented rooms have to be carefully designed to prevent overheating. Design options for prevention of overheating, however, correspond well with options for low space heating demand. Glazings with solar control coating are therefore obvious alternatives to dynamic solar shadings. Regarding room geometry, deep or narrow south-oriented rooms show difficulties in reaching sufficient daylight levels without overheating.
This paper describes the linking of the popular three-dimensional CAD modeler Rhinoceros with advanced daylight simulations using Radiance and Daysim. A new, highly effective design workflow within Rhinoceros is presented that directly exports scene geometries, material properties and sensor grids into Radiance/Daysim format and calculates a series of performance indicators including monthly or seasonal solar radiation maps as well as daylight factor and daylight autonomy distributions. The simulation results are automatically loaded back into the Rhinoceros scene using falsecolor mappings. Using the Grasshopper plug-in for Rhinoceros, key design parameters such as window size and material descriptions can be changed incrementally and the simulation results can be combined into an animated building performance simulation, i.e. a dynamic visualization of the effect of these design parameters on the daylight availability within the scene. The design workflow has been specifically developed with the architectural design process in mind, aiming to provide designers with immediate, high quality feedback all the way from schematic design to design development.
This paper presents one of the first national scale studies of summertime temperatures in English dwellings. Living room and bedroom temperatures were recorded in 207 homes across the England during the cool summer of 2007. Data was also collected by face-to-face household interviews. Fourteen homes (7%) were observed to be heated for part or all of the analysis period (July to August). Based on the BSEN15251 adaptive thermal comfort model, the 193 free-running dwellings would, in general, to be considered as uncomfortably cool. Over 72% of living rooms and bedrooms had more than 5% of hours below the BSEN15251 Cat II lower threshold, with over 50% having more than 5% of hours below the Cat III threshold. Detached homes and those built before 1919 were significantly cooler (p < 0.05) than those of other type and age. Static criteria revealed that, despite the cool summer, 21% of the bedrooms had more than 5% of night time hours over 26 °C; which is a recommended upper limit for bedrooms. The bedrooms of modern homes, i.e. those built after 1990 or with cavity walls, were significantly warmer (p < 0.05). The bedrooms in homes built prior to 1919 were significantly cooler (p < 0.05). The living rooms of flats were significantly warmer than the living rooms in the other dwelling types (p < 0.05). The incidence of warm bedrooms in modern homes, even during a cool summer, is of concern, especially as there is a strong trend towards even better insulation standards in new homes and the energy-efficient retrofitting of existing homes.
This article compares daylight simulation results generated with two simulation programs, Autodesk® 3ds Max® Design 2009 (3ds Max Design) and Daysim 3.0 (Daysim), to indoor illuminance measurements in a sidelit space. The sidelit space was in a single location, but was configured with five fenestration and glazing options, and operated under a variety of sky conditions. The measurements form a set of ‘daylighting test cases’ that were recently developed to evaluate the simulation capabilities and limitations of different daylight simulation programs. Both 3ds Max Design and Daysim were given external direct and diffuse irradiances as simulation input, from which the programs predicted indoor illuminances on a grid of upward facing work plane sensors and downward facing ceiling sensors.
3ds Max Design is based on Exposure™ technology, a lighting analysis module that includes a ‘shader’ of the Perez sky model and that uses the mental ray® raytracer for the global illumination calculation. Daysim also uses the Perez sky model and is based on the Radiance backward raytracer combined with a daylight coefficient approach. The comparison of both programs with measurements demonstrated that 3ds Max Design simulated indoor illuminances for the daylighting test cases with reliability comparable to Daysim. Most mean bias errors and root mean square errors were in the range of those reported in earlier validation studies: both programs succeeded in reproducing measurements for a sidelit space with and without a lightshelf. While 3ds Max Design consistently underestimated the incoming light flux going through a translucent panel, Daysim results were lower than measurements for the internal venetian blind test case. The results suggest that the accuracy of both programs is sufficient for typical daylighting design investigations of spaces with complexity comparable to the five daylighting test cases.
Daylighting and the impact of daylighting strategies on the visual environment continue to be a vital issue for building occupants due to visual comfort and user acceptance of luminous indoor environments. Some of the critical factors affecting the level of visual comfort and quality in daylit office spaces include glare, window luminances, and luminance ratios within the field of view. One of the goals of this study was to provide new insight into the impact of luminance distributions on glare. The luminance distribution within the field of view was recorded using CCD camera-based luminance mapping technology. The technology provides a great potential for improved understandings of the relation between measured lighting conditions and user response. With the development of the RADIANCE based evaluation tool “evalglare”, it became possible to analyse glare according to a number of daylight glare prediction models as well as contrast ratios in various daylit situations (workplace, VDU). User assessments at two locations (Copenhagen, Freiburg) with more than 70 subjects under various daylighting conditions were performed in order to assess existing glare models and to provide a reliable database for the development of a new glare prediction model. The comparison of the results of the user assessments with existing models clearly shows the great potential for improving glare prediction models. For the window luminance a squared correlation factor of only 0.12 and for the daylight glare index (DGI) of 0.56 were found. Due to the low predictive power of existing glare prediction models a new index, daylight glare probability (DGP), was developed and is presented in this paper. DGP is a function of the vertical eye illuminance as well as on the glare source luminance, its solid angle and its position index. The DGP showed a very strong correlation (squared correlation factor of 0.94) with the user's response regarding glare perception.
The objective of this document is to promote the use of dynamic daylight performance measures for sustainable building design. The paper initially explores the shortcomings of conventional, static daylight performance metrics which concentrate on individual sky conditions, such as the common daylight factor. It then provides a review of previously suggested dynamic daylight performance metrics, discussing the capability of these metrics to lead to superior daylighting designs and their accessibility to non-simulation experts. Several example offices are examined to demonstrate the benefit of basing design decisions on dynamic performance metrics as opposed to the daylight factor. L?objectif visé par ce document est de promouvoir l'utilisation de mesures de la performance sous éclairage naturel dynamique aux fins de la conception de bâtiments durables. Comme point de départ, ce document explore les lacunes des paramètres de mesure conventionnels de la performance sous éclairage naturel statique, lesquels visaient les conditions de ciel prises individuellement, comme le coefficient d'éclairage diurne courant. On fournit ensuite un examen des paramètres de mesure de la performance sous éclairage naturel dynamique qui avaient été auparavant suggérés, et traite de la capacité de ces paramètres de mesure à générer des conceptions d'éclairage naturel supérieures et de leur accessibilité aux non-spécialistes en matière de simulation. Plusieurs types de bureaux sont examinés comme exemples de l'avantage découlant de décisions de conception qui soient fondées sur des mesures de performance dynamiques au lieu du coefficient d'éclairage diurne. RES
The presence of natural light in indoor spaces improves human health, well-being, and productivity, particularly in workplace environments. Do the social benefits of daylight translate into economic value as measured by what office tenants are willing to pay? Using a sample of 5154 office spaces in Manhattan, we pair urban daylight simulation with a hedonic valuation model to determine the marginal value of daylight in offices. Holding all other factors constant, we find that occupied spaces with access to high amounts of daylight (as measured by 55% spatial daylight autonomy) have a 5–6% value premium over occupied spaces with low amounts of daylight (as measured by less than 55% spatial daylight autonomy). We simulate the distribution of daylight on each office floor individually, taking into account architectural and location-specific characteristics. Then, using the hedonic model, we determine the added value of daylight in the office spaces. The results show, for the first time, that an estimated 74% of office spaces throughout Manhattan have low daylight, and that in a dense urban environment with differentiation in daylight levels, tenants value high daylight. Daylight value is independent of other building, neighborhood, and contract characteristics. By revealing the added value of daylight in commercial office spaces, we suggest that daylight is a key design driver and thus, should be considered in design, policy, planning, and project financing.
Thermal and visual comfort are important for the health and productivity of occupants in office buildings. In this paper, we present a simulation-aided approach in analyzing and optimizing lighting and thermal conditions in building interiors, encompassing the modelling of the interior space in virtual facilities, ray-tracing simulations for illumination prediction, and computational fluid dynamics/heat transport simulations for airflow and ambient temperature predictions. This is carried out with the aim of optimizing visual-thermal comfort in an indoor environment while adhering to comfort and safety guidelines. We demonstrate the methodology on a real-world case study on an office building in Singapore, improving lighting and thermal conditions greatly through passive daylight fixtures and the reconfiguration of climate-control air supply vents within the office space. A significant reduction of energy consumption was simultaneously achieved, amounting to >7% in lighting and cooling expenditure. The presented methodology allows rapid iteration and evaluation over plausible designs in enhancing indoor environmental quality and building energy performance, especially relevant when performance and sustainability goals have to be balanced.
Roof windows are widely used in northern European countries, contributing positively by giving daylight, passive solar heat and view to the outside. In order to improve their thermal property, triple glazing unit together with external shutter are more and more common on the market. Additionally, the junction part between window and roof is also important since it greatly influences the linear thermal transmittance (LTT) along edges of the window and the daylight level of the room. This research presents a parametric analysis for roof windows with triple glazing unit and external shutter from perspectives of energy, daylight and thermal comfort. The investigation can be described in two parts:
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Analysis of thermal and comfort performance for triple glazing unit with an external shutter.
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Analysis of combined performance of daylight level and LTT for roof windows.
Performances of energy and thermal comfort of triple glazing unit with external shutter can be influenced by different properties, including the width of the cavity between shutter and external pane, air penetration rate through the cavity between shutter and external pane, the tilt angle of the window. The study conducts analysis on the energy and comfort performances of the window by calculating U-value of the entire window and internal surface temperature of the glazing. The calculations are performed by a model developed via state-space modelling using Simulink/MATLAB. The results reveal that the external shutter improves both the thermal and comfort performances of the window.
The ways of installing windows on a roof and cutting on the internal wall along window edges also have great influences on the combined performance of daylight level and LTT along the edge between window and roof. Therefore, daylight and LTT are also evaluated with different parameters, including the thickness of roof insulation, installation level of windows on the roof, cutting of lining and extra insulation around the perimeter of windows. The analysis is conducted using DIVA/Rhino and Flixo. The calculations show that the lower installation level and extra insulation around the window frame can decrease linear thermal transmittance of the entire window by more than 60 %.
It has become evident that southern Europe will experience more adverse climate change effects compared to other European regions. The current study aims to investigate the vulnerability of educational buildings in Cyprus, in view of future climatic conditions, by means of a dynamic simulation software. In addition, the influence of natural ventilation on the thermal comfort in the current and future climatic conditions is examined. The research indicates that educational buildings in southern Europe are unable to meet the thermal comfort criteria for more than 70% of the time, which entails a major impact on the environmental, economic and social interaction of people and buildings. The results show that night ventilation is an effective strategy for the reduction of the risk of overheating especially in the TMY; however, this strategy alone is unable to cope with future overheating predictions. Natural ventilation alone can achieve a reduction of hours where operative temperature exceeds the CIBSE maximum limits of 28-35% by 2050s and of 9-11% by 2090s. The evaluation of the resilience of existing educational buildings is useful in understanding the necessity of energy retrofitting measures in view of future climate conditions, contributing to energy efficiency policies and decision-making regarding retrofit interventions.
Fully glazed façades are still preferred by many architects due to their aesthetic features. Although this choice offers opportunities for daylighting and view contact with the outside, it can lead to overheating and glare problems if climate is not taken into account in the design. This paper presents a workflow for retrofitting that can be applied to different office façades with large window-to-wall ratios. The workflow consists of analysing the space from the point of view of the functions of its façade and then applying a retrofitting strategy based on state-of-the-art building simulations and automated shading control. The proposed workflow is illustrated by a case study at an office in Malaga (Spain), in which the originally installed, manually-controlled interior vertical blinds are replaced with automatically controlled interior roller blinds with a metallized reflecting surface facing towards the glazing unit. A full optical characterization of the roller blinds is presented. A simulation-based control strategy is applied to the motorized roller blinds in order to maximize view contact with the outside and daylighting while controlling glare and overheating.
This study provides information about development of cost-effective facade solutions during the last 5 years and illustrates the importance of different variables such as accuracy of window models, construction costs, energy prices, interest rate and inflation. The cost-effective South, East and West facade solutions were triple windows with window-to-wall ratio 22-40% and external wall mineral wool insulation thickness 150-200 mm, whereas larger windows could be used in the North facade. The economic variables and construction price changes have had the largest influence on the analysis of cost-effective facade solutions. Lowest energy use was achieved with large quadruple windows and automated external venetian blinds with an advanced control algorithm. Wider market uptake of efficient window solutions could allow more architectural freedom from the point of view of energy-efficient and financially feasible facade design. Using detailed window models instead of standard windows did not influence the cost-optimal facade solutions, but had energy and load effects in both directions.
Daylighting technologies have been developed recently to harness solar energy, and eventually, meet the goals of sustainable development. However, the use of natural light in the tropics is challenging. Many factors limit the efficiency of solar energy because of the intensity of solar irradiance and the inconstancy of sky conditions in this region. This research aims to design and evaluate an integrated daylighting system for enclosed spaces without access to daylight from side openings. The proposed system eliminates the requirements for electrical lighting during daytime. The new design combines three components, namely, roof light, dynamic shading, and fiber optic daylighting system, in one integrated platform. The methodology was based on a quantitative approach that used empirical experiments in an actual-sized room. Two stations were set up outside and inside the test cell for data collection. The study used a data acquisition system with nine calibrated sensors to record the performance of the integrated day-lighting system. The readings indicated the capability of the system to control natural light from 8:00 to 18:00, even during peak hours. Results showed that the proposed system utilized and boosted the efficiency of the individual components, and the fiber optic daylighting system delivered sufficient level of natural light within the range of 300–680 lx, at an average of 492 lx, with functionality ranging from 44% to 54%. In addition, the skylights were controlled with a dynamic shading system and delivered a maximum reading below 2000 lx during peak times, at an average of 350 lx, with functionality between 46% and 56% under the intermediate sky condition. The integrated daylighting system delivered uniform illuminance when solar irradiance was above 500 W/m 2 .
To ensure sufficient daylight in rooms, daylight performance metrics are the basic references to guide building design or to benchmark a building against another in terms of daylighting in a room. Daylight factor (DF) is the most commonly accepted daylight performance metric, but it has limitations in evaluating the daylighting of a room space in a real daylight climate, as defined under CIE standard overcast sky, while daylight autonomy (DA) is a climate-based performance metric which takes into consideration the regional daylight climate. Based on long-term continuous measurements of daylight illuminance in a test room under real climate, combined with scale model tests under an artificial sky and computational simulations, the quantitative relationship between monthly average daylight illuminance, DF and DA are holistically analyzed in this paper. The result shows that a monthly average daylight illuminance above 300 lx in a room located in Canton requires a DF of no less than 1.8% for north-facing space. Finally, the depth of DA300lx [50%] daylit area for four cardinal directions was proposed in comparison with DF.
The purpose of this study is to quantify the gap between the calculated energy need of a building model with simplified and detailed windows and suggest a method for reducing the gap. A model of a detached house in the cold climate of Estonia was composed and its energy needs with triple and quadruple windows was studied. The window sizes and opening strategies were also varied and all cases were modelled with simplified and detailed window models of which the latter were modelled pane by pane according to the methodology of ISO 15009. Simplified window models resulted in heating need lower by up to 7% and cooling need higher by up to 23%. The optimal window sizes of South facing triple windows remarkably depended on the glazing model and window opening strategy used. Therefore using simplified window models and inappropriate methodology might lead to inadequate facade design. In case of triple windows multiplying the U-value of simplified window models by 1.15 minimized the mismatch in calculated heating needs with different window models. It is recommended to use detailed window models to be used in simulations of mechanically cooled buildings.
This paper examines several existing methods of static shading device design, and presents a new approach called SHADERADE. The approach is implemented as an eponymous tool based on Rhinoceros® and EnergyPlus, and offers flexible, novel techniques for assessing the thermal desirability of solar transmittance through any potential shading volume or surface. Using simulated sidelit offices located in Anchorage, Boston and Phoenix, it is shown that SHADERADE is able to consistently generate shading systems with improved thermal performance vis-à-vis existing methods. It is also shown that the approach can handle curved geometries with ease, and can effeciently manage the sizing of shading devices by identifying regions that matter most. The authors hope that these capacities will facilitate a more effective, less prescriptive approach to shading design.
Many aspects of human physiology and behavior are dominated by 24 h rhythms that have a major impact on our health and well-being. The daily light-dark cycle plays the primary role in synchronizing these rhythms with the 24 h day. The properties of light that determine the efficacy of its circadian phase-resetting effects include the timing, intensity, duration, pattern, wavelength, and history of exposure. Major advances have been made in understanding how light is detected by the eye to reset circadian rhythms. A novel photoreceptor system has been discovered that mediates circadian photic responses that is anatomically and functionally distinct from the visual system.
Daylight has been recognized as a free energy and cost effective alternative to artificial lighting for sustainable building design. It could also provide a more pleasant and attractive indoor environment for its good color rendering and it matches the human visual response much better than artificial light source. The effects of daylight on the occupancy comfort, health, well-being and productivity are well acknowledged. However, despite the above advantages, daylight is not widely integrated with the artificial lighting in building design as there is lack of information and evaluation tools on the suitability of daylight and its energy saving potential. The procedure of evaluating the indoor daylight performance consists of two parts: one is to assess the indoor daylight availability by either simulation or field measurements; another one is to accurately estimate potential energy saving when sufficient daylight is provided. This paper therefore presents a review of metrics and methods for indoor daylight availability assessment, as well as estimation methods used for predicting potential energy saving from daylight. The aim of this paper is to provide building designers or operators some useful information so that more daylight schemes could be considered in sustainable building design.
A new Radiance-based modelling approach called Fener is presented. The motivation is to be able to perform detailed analyses of complex fenestration systems (CFS) from the energetic and daylighting points of view in a computationally efficient manner, so the benefits of innovative products can be easily quantified. The model couples daylighting and thermal simulations in a time-step basis, so that shading control strategies that depend on thermal variables, such as indoor air temperature and energy load, can be simulated without iterating between full-year simulations of a thermal model and a daylighting model. Fener is a single-zone energy model that uses the three-phase method and bi-directional scattering distribution functions (BSDF) to predict the transmitted solar irradiance and indoor illuminance of office spaces with CFS. An evaluation of the model is presented. Fener is tested against EnergyPlus and classic Radiance for different fenestration systems and sky conditions. Cooling and heating energy demand, transmitted solar irradiance and indoor illuminance are compared. As an exemplary application, Fener is used to assess the performance of an innovative perforated lamella system together with a control strategy that depends on indoor air temperature.
In Nordic countries overheating problems have not constituted a recognized problem to date. However, modern buildings, typically with larger windows, have changed this situation. New regulations based on Energy Performance of Buildings Directive (EPBD) directive require that overheating problems are controlled and recommend the use of passive cooling measures. EPBD sets that temperature simulations or other verifications are to be used at the design stage. If necessary, passive measures may be supported with active cooling systems to meet the requirements for summer thermal comfort. During this study field measurements were conducted in more than 100 Estonian apartments by recording indoor temperatures from a 3-month period; an overheating assessment and the impact of ventilation, orientation and window size on recorded overheating were studied. Our results show that overheating occurs in the modern buildings where the average room temperature was continuously about 1K higher than in the old buildings. According to the criterion of weighted excess degree hours over+27°C used in Estonian regulation to prevent overheating, no overheating occurred in old apartment buildings, but the criterion was exceeded in 13.7% of the apartments in new apartment buildings. The results showed that, without adequate passive temperature damping measures used, modern buildings were regularly overheated.
Cost optimal and as energy efficient as possible facade solutions, including window properties, external wall insulation, window-to-wall ratio and external shading were determined with energy and daylight simulations in the cold climate of Estonia. Heating dominated in the energy balance and therefore windows with higher number of panes and low emissivity coatings improved energy performance. The window sizes resulting in best energy performance for double and triple glazing were as small as daylight requirements allow, 22-24% respectively. For quadruple and hypothetical quintuple glazing the optimal window-to-wall ratios were larger, about 40% and 60% respectively, because of daylight utilization and good solar factor naturally provided by so many panes. The cost optimal facade solution was highly transparent triple low emissivity glazing with window-to-wall ratios of about 25% and external wall insulation thickness of 200 mm (U=0.16). Dynamic external shading gave positive effect on energy performance only in case of large window sizes whereas due to high investment cost it was not financially feasible. Limited number of simulations with Central European climate showed that triple glazing with double low emissivity coating and window-to-wall ratio of about 40%, i.e. slightly larger and with external shading compared to Estonian cost optimal one, clearly outperformed conventional design.
Modern office buildings often have large glazed areas. Incident solar radiation can lead to large cooling demands during hot periods although the solar radiation can help reduce heating demands during cool periods.
Previous studies have shown that large parts of the net energy demand of an office building is related to window heat loss and cooling demands induced by solar irradiance. In this article, the authors found that, even in what traditionally has been considered to be a heating-dominated climate, cooling demands dominate the net energy demand of an office building. Solar shading systems are vital to reduce the cooling demand of an office building.
Introducing shading systems might contribute to higher heating demands as well as higher demands for artificial lighting but at the same time it might be necessary in order to reduce glare issues.
Simulations of a number of shading strategies have been performed for south- and north-facing office cubicles with varying floor areas, window sizes and window parameters. Energy demands for heating, cooling, lighting and ventilation fans have been assessed. The simulations show that the choice of shading strategy can have an impact on the energy demand of the offices. Depending on strategy, the energy demand can either increase or decrease compared to an unshaded one- or two-person office cubicle.
In addition, the shading systems can contribute toward a lowered thermal transmittance value (U-value) of the window by functioning as an additional layer in the glazing unit when closed. Potential improvements of U-values have been studied in combination with the shading system’s effect on solar heat gains and daylight levels. Experimental investigations of in-between the panes solar shading system effects on window U-values are currently being carried out at the Research Centre on Zero Emission Buildings (www.ZEB.no).
It was found that automatically controlled shading systems can reduce the energy demands of south-facing, small office cubicles, but that they should not be installed without a thorough case-by-case investigation as increased energy demands were found if an improper shading strategy was chosen. Upgrading to four-pane glazing will, however, always have a beneficial impact on the energy demand compared to two- and three-pane glazing.
The present work discusses simulation results of annual indoor illuminance distributions for two office geometries situated in Freiburg, Germany, calculated with six different RADIANCE-based daylight simulation methods. These methods are the ubiquitous daylight factor method, ADELINE 2.0, the classified weather data according to Herkel and Pasquay and two simulation procedures based on daylight coefficients according to Tregenza, namely ESP-r version 9 series and a new accelerated method developed by the authors. The new method calculates 145 diffuse and three ground daylight coefficients in a single raytracing run which considerably reduces the required calculation times for an annual daylight simulation. An explicit calculation of the indoor illuminances under all 4703 annual hourly mean sky luminance distributions from the Freiburg test reference year (TRY) serves as a reference case against which the other methods are tested. The simulation results reveal that the accuracy of an annual daylight simulation method is not necessarily coupled with the required simulation time. The quality of an annual simulation rather depends on the underlying sky luminous efficacy model and whether the method considers the hourly mean direct and diffuse illuminances for each time period explicitly. The two methods relying on daylight coefficients exhibit the lowest relative root mean square errors (RMSEs) for the straightforward office geometry. The results for the advanced office show that internal illuminance contributions due to external ground reflections are only considered by the new method.
The objective of this study was to perform a daylighting analysis on the light shelf system installed to save energy in office buildings in Tamil Nadu. For this, a building was chosen for energy analysis simulation using Ecotect software. Light shelves with four different patterns of diffuse reflections in increasing levels were chosen at the preliminary stage. The illuminance was highest in the mirror finish followed by high reflective, medium reflective and light reflective partitions. The light shelf with the mirror finish was chosen for the economic analysis since it is more efficient than other diffuse reflection panels. Results of the economic analysis showed that lighting energy consumption was reduced by an average of 30% using the mirror finished light shelf with energy efficient lamps, compared with the base case model where lighting control was not applied. A simple payback period, calculated for the model with the light shelf system installed was 6 years and 4 months.
Despite the significant impact that the position of movable shading devices has on building energy use, peak loads, and visual and thermal comfort, there is a high degree of uncertainty associated with how building occupants actually operate their shades. As a result, unrealistic modeling assumptions in building performance simulation or other design methods may lead to sub-optimal building designs and overestimation or underestimation of cooling loads. In the past 35 years, researchers have published observational studies in order to identify the factors that motivate building occupants to operate shading devices. However, the diversity of the study conditions makes it is difficult to draw universal conclusions that link all contributing factors to shade movement actions. This paper provides a comprehensive and critical review of experimental and study methodologies for manual shade operation in office buildings, their results, and their application to building design and controls. The majority of the many cited factors in office buildings can be categorized into those affecting visual comfort, thermal comfort, privacy, and views. Most office occupants do not operate their shades more than weekly or monthly and they do so based on long-term solar radiation intensity and solar geometry trends rather than reacting to short-term events. They generally operate them to improve visual conditions rather than thermal conditions. Occupants in offices with automatically-controlled heating and cooling tend to be less diligent about using shading devices to improve their comfort.
This paper describes the application of a new paradigm, called useful daylight illuminance (UDI), to assess daylight in buildings. The UDI paradigm is designed to aid the interpretation of climate-based analyses of daylight illuminance levels that are founded on hourly meteorological data for a period of a full year. Unlike the conventional daylight factor approach, a climate-based analysis employs realistic, time-varying sky and sun conditions and predicts hourly levels of absolute daylight illuminance. The conventional approach produces a single number – the daylight factor as a percentage – for each evaluation point in the space. In contrast, a climate-based analysis results in an illuminance prediction for every daylight hour of the year for each point considered. The UDI paradigm offers a way to reduce the voluminous time-series data to a form that is of comparative interpretative simplicity to the daylight factor method, but which nevertheless preserves a great deal of the significant information content of the illuminance time-series. The UDI paradigm informs not only on useful levels of daylight illuminance, but also on the propensity for excessive levels of daylight that are associated with occupant discomfort and unwanted solar gain. In a conventional analysis of daylight provision and solar penetration, the two phenomena are assessed independently using methods that are idealised (daylight factor) and qualitative (shadow patterns). The UDI paradigm offers a simple methodology whereby daylight provision and levels of solar exposure are quantified using a single evaluative schema. Thus, it is also well-suited for teaching purposes. Application of the UDI paradigm is demonstrated using an analysis of design variants for a deep-plan building with a light-well. Comparison is made with the conventional daylight factor approach, the LEED daylight credit and measures of daylight autonomy.
Sun-shading systems have to provide thermal and visual comfort reliably and economically. At the same time, they should prevent unwanted solar gains in summer and permit high solar gains in winter. This paper describes a method for the assessment of the heat barrier effect of different types of sun-shading systems together with the associated control strategy. The starting point for the performance assessment is adequate characterization, appropriate to the size and complexity of the facade of the assessed building. The thermal characterization consists of the angle-dependent determination of the Total Solar Energy Transmittance g with a calculation method, which is validated with calorimetric measurements. The combination with typical irradiance distributions allows the evaluation of different control strategies. This paper shows that it is essential for the reliability of the calculated cooling and heating loads, that this calculation is based on a control strategy, that fits with the priorities of the building users.
This paper describes a physically-based rendering system tailored to the demands of lighting design and architecture. The simulation uses a light-backwards ray-tracing method with extensions to efficiently solve the rendering equation under most conditions. This includes specular, diffuse and directional-diffuse reflection and transmission in any combination to any level in any environment, including complicated, curved geometries. The simulation blends deterministic and stochastic ray-tracing techniques to achieve the best balance between speed and accuracy in its local and global illumination methods. Some of the more interesting techniques are outlined, with references to more detailed descriptions elsewhere. Finally, examples are given of successful applications of this free software by others.
The circadian system in animals and humans, being near but not exactly 24-hours in cycle length, must be reset on a daily basis in order to remain in synchrony with external environmental time. This process of entrainment is achieved in most mammals through regular exposure to light and darkness. In this chapter, we review the results of studies conducted in our laboratory and others over the past 25 years in which the effects of light on the human circadian timing system were investigated. These studies have revealed, how the timing, intensity, duration, and wavelength of light affect the human biological clock. Our most recent studies also demonstrate that there is much yet to learn about the effects of light on the human circadian timing system.
Building Envelope Impact on Human Performance and Well-Being: Experimental Study on View Clarity
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