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Outdoor Comfort: the ENVI-BUG tool to evaluate PMV values point by point
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... It is designed for microscale analysis (normal horizontal resolution of 0.5-10 m; typical time frame of 24-48 h; time step of 1-5 s), allowing researchers to investigate smallscale interactions between individual buildings, surfaces, and plants (Chatzinikolaou, Chalkias, and Dimopoulou 2018;Sule Zango et al. 2018;Xiaoshan Yang, Lihua Zhao, Michael Bruse 2013;Fairuz et al. 2012;Maleki et al. 2014). ENVI-met also offers precise outputs, including the PMV, PET, UTCI and SET indexes space distribution, based on a three-dimensional microclimate model (Fabbri et al. 2017). PET is an accurate index, and the results give a clear indication of the comfort temperature because it is still measured in degrees, hence PET is employed in outdoor thermal comfort calculations (Setaih, Hamza, and Townshend 2013;Huang et al. 2018;Elnabawi and Hamza 2020;Galal, Sailor, and Mahmoud 2020). ...
... Other researches have discussed how the lack of air velocity is a fundamental limitation of this technique: temperatures and velocity fields are separated, therefore established assumptions don't always adequately represent real-time velocity and temperature interactions (Crank et al. 2020;Setaih et al. 2014). In addition, the program demonstrates several limits in terms of human metabolic activity and clothing (Fabbri et al. 2017). ...
Thermal comfort plays a significant role in encouraging people to utilize outdoor spaces. Therefore, this feature must be analyzed and evaluated in order to be improvised. Computational fluid dynamics (CFD) is an alternative technique that predicts thermal comfort and environmental parameters. Validation of CFD is important to ensure its effectiveness. This study assessed the performance of ENVI-met for its ability to estimate thermal indices (PET) by comparing it to field measurement for various points in a street canyon in Port Said, Egypt, throughout the summer and winter seasons. Except for the limited air velocity correlation, the results presented very good agreement, particularly with respect to the final results of the PET visually curved and numerical values, with an index of agreement value ranging from 0.81 to 0.95. The study's conclusions concern the use of the ENVI-met simulation model as a tool for assessing outdoor thermal comfort.
... A type of thermal comfort index known as the predicted mean vote (PMV) was presented by Fanger in 1970 as the ASHRAE standard 55 and the ISO 7730 standard [57][58][59][60][61][62][63][64][65][66][67]. PMV was developed to evaluate the thermal comfort of humans in a controlled IEQ using a HVAC system [57][58][59][60]64] (Equations (1)-(4)). ...
... where PMV is the predicted mean vote, M is the metabolic rate, W is the effective mechanical power, Pa is the water vapor partial pressure, ta is the air temperature, fcl is the clothing surface area ratio to the body surface area, tcl is the clothing surface temperature, Icl is the thermal resistance of clothing, Tmrt is the mean radiant temperature, hc is the convective heat transfer coefficient, and Var is the relative air velocity Unfortunately, PMV factors are focused on indoor thermal comfort; therefore, it is not appropriate to use PMV for outdoor thermal comfort based on previous research [57][58][59][60][61][62][63][64][65][66][67]. Hőppe presented the PET to address this issue. ...
Fatal injury and accidents in the construction industry occur under the influence of outdoor weather conditions such as temperature, humidity and wind speed in all four seasons. Previous research in this area has focused on hot and cold weather conditions: hot weather causes heat rash, heat cramps and heat fainting, while cold weather causes fatigue, lumbago, and cold finger sensations. However, other weather conditions are also associated with, and cause, fatal injury and accidents. Accordingly, this study analyzes injury and fatal accidents in the construction industry based on the physiological equivalent temperature (PET) as it pertains to thermal comfort using an uncertainty analysis. Furthermore, using a neural network, relative importance is analyzed considering injury and fatal accidents. This study is conducted in five steps: (i) Establishment of the database, (ii) Classification of accident types and weather conditions, (iii) Calculation of thermal comfort, (iv) Analysis of injury and fatal accidents based on thermal comfort, and (v) Calculation of the relative importance of thermal comfort during injury and fatal accidents. Via the research process, 5317 fatal incidents and 207,802 injuries are analyzed according to 18 accident types in all seasons. It was found that ‘falls’, were the most frequent fatal incident and injury (2804 fatal incidents and 71,017 injuries), with most of these occurring during the autumn season. The probabilities of injury and fatal accidents in the ‘fall’ category are 86.01% and 85.60%, respectively, in the outside comfort ranges. The contribution of this study can provide data for a database on safety management considering weather conditions.
... Nonetheless, the ISO framework has a broad applicability, which can be adapted to individual projects by choosing the most important aspects for analysis. However, most papers are limited to the analysis of simulations with a focus on particular software features [29,[31][32][33]. Other papers have compared simulations between different software tools to validate their results [32] and to define the differences between calculation rules [33]. ...
This paper investigates the capabilities and limitations of different software tools simulating landscape design adaptability. The evaluation of tools is based on the ISO 25010 framework, which investigates software functionality, reliability, performance efficiency, usability, compatibility, and information quality. These quality characteristics of software are analysed during objective experiments where five software tools are used for a case study project at the conceptual design phase. These experiments reveal that the existing software tools for climate adaptation planning are focused on different aspects of climate adaptability, generating different types of information. Moreover, all tools deal with some limitations in terms of compatibility, performance efficiency, and functional operations. The ISO 25010 quality model provides a comprehensive framework to compare the capabilities of different software tools for climate adaptation planning. This paper is part of a wider study including an analysis of the needs of project stakeholders regarding climate adaptation software tools. However, this article focuses on technical capabilities of current climate adaptation software tools.
... A trade-off of its comprehensiveness is the ensuing compute times-in fact, a whole-day simulation can easily take 24 hours or more to complete even on a high-performance computer. Two Grasshopper plugins, lb_envimet and df_envimet, enhance the feasibility of ENVI-met as a complement to the architectural design process [14,15], but their diffusion is still limited. ...
In the context of global climate change, it is increasingly important for architects to understand the effects of their interventions on indoor and outdoor thermal comfort. New microclimate analysis tools which are gaining appreciation among architects enable the assessment of different design options in terms of biometeorological parameters, such as the Universal Thermal Climate Index (UTCI) and the Outdoor Thermal Comfort Autonomy. This paper reflects on some recent experiences of an architectural design office attempting to incorporate local climatic considerations as a design driver in projects. The investigation shows that most of the available tools for advanced climatic modelling have been developed for research purposes and are not optimized for architectural and urban design; consequently, they require adaptations and modifications to extend their functionality or to achieve interoperability with software commonly used by architects. For this scope, project-specific Python scripts used to extract design-consequential information from simulation results, as well as to construct meteorological boundary conditions for microclimate simulations, are presented. This study describes the obstacles encountered while implementing microclimate analysis in an architectural office and the measures taken to overcome them. Finally, the benefits of this form of analysis are discussed.
... A common way to assess outdoor comfort is the estimation of comfort indices. Several indices have been proposed and used for the assessment of outdoor thermal comfort, such as PET (physiological equivalent temperature), OUT-SET (outdoor standard effective temperature), TEP (temperature of equivalent perception), and UTCI (universal thermal climate index) [57][58][59][60][61][62][63][64][65]. Various studies related to outdoor thermal indices in urban Mediterranean environments have been developed [66][67][68][69]. ...
Comfort in public spaces is essential to their attractiveness and continued role in improving human quality of life. Acceptable thermal conditions are determinant to ensuring users’ comfort. This study undertakes an assessment of three urban sites in Arouca, in the north of Portugal, using ENVI-met software. Simulations test the influence of pavement and façade covering material, vegetation, and site morphology. The climate of the region is classified as Mediterranean Csb, with rainy winters and dry and mildly warm summers. A typical summer day is considered. The results reveal that a combination of factors might lead to thermal discomfort even in this mild climate on an average day, mainly due to heat exchange by radiation. In addition, the impact of alterations to surface properties depends on the morphological characteristics of the site, e.g., high albedo of the pavement may lead to a decrease or an increase in mean radiant temperature, depending on the space. This variability is present in the effects observed at the studied sites. A high façade albedo always contributes, in these cases, to thermal discomfort. The conclusions of the present study highlight the importance of performing a specific study for each urban site whenever an intervention is to be planned.
... and the Grasshopper Ladybug & Honeybee Tool. Through the expanded EnergyPlus weather STATistics (STAT) data provided in the EPW File, typical summer and winter days were set, and a comfort mannequin overlooking the southward direction was used as an analysis surface to calculate insolation [52]. In addition, the control of environmental factors is very important in this simulation. ...
The purpose of this research is to examine whether eum-taek, a feng shui theory for the dead, can be applied to Korean modern architecture. In the first step, common environmental factors that are valued in both feng shui and ecological architecture were derived, and then this research reviewed how properly the traditional site assessment method evaluated them; for example, metaphorized basic concepts of the evaluation theory based on territorial settings can be applied to evaluate common environmental factors. For the second step, this paper reviewed whether the evaluation method for feng shui presented in the previous step was applied equally between yang-taek and eum-taek theories, investigated the differences between them in general, and derived environmental factors to be utilized for evaluation in the field of architecture. As a result, it was found that the major concepts presented in the previous step have been commonly used evaluation criteria, regardless of the categories from traditional theories. The third step was to simulate whether sites selected by each theory actually have similar environmental conditions. The simulation analysis found that all analysis sites were able to obtain a higher sun exposure time than the Korean average; therefore, it was considered that their locations could have environmental advantage, in terms of solar radiation and thermal environment. The simulation results confirm that the target sites have a living environment that would be easy for humans to live in. Finally, the simulation results confirm that the eum-taek site has a living environment that is comfortable for humans to live in. If studies of the site assessment method are carried out considering yang-taek and eum-taek with different evaluation categories, the modern applicability of feng shui may increase.
... The physical morphology of the study area was constructed using Rhino, a 3D computer-aided design (CAD) program; Grasshopper, a visual scripting interface for Rhino; Ladybug, an environmental analysis plugin for Grasshopper (Sadeghipour Roudsari & Pak, 2013); and lb_envimet, a plugin for Ladybug that converts Rhino geometry to an ENVI-met model (Fabbri, Di Nunzio, Gaspari, Antonini, & Boeri, 2017). For all scenarios, two surface profiles were used: 10 cm thick asphalt roads and 5 cm grass. ...
Cities are increasingly incentivizing rooftop photovoltaics (PV) for the reduction of greenhouse gas emissions together with more urban forestry and high albedo surfaces for the mitigation of the urban heat island (UHI) effect. Previous interventions are proven to be effective in isolation, but their combined performance is seldom considered. Through microclimate simulations of a neighbourhood in Brampton, Ontario, this study investigates the trade-offs between large-scale deployments of rooftop PV, street trees, and cool roofs. The performance of each intervention is compared by examining the impact on the PV efficiency (and the produced electricity) and the Universal Thermal Climate Index (UTCI) values. The study shows that street trees can reduce the energy output of rooftop PV significantly depending on their height and location, and it confirms the need for solar access laws, currently missing in Ontario. Further, this study shows that a large adoption of rooftop PV instead of cool roofs can result in an outdoor environment up to 0.5 °C higher in terms of UTCI during heatwave periods.
Recently, achieving outdoor thermal comfort has attracted considerable attention in many studies in regions with hot and humid climates. Sun sails have been used as a traditional street-shading strategy in cities to improve outdoor thermal comfort, but their advantages in achieving thermal comfort in school courtyards remain unexplored. This study improves thermal comfort in school courtyards by studying the effect of the sun sail-shading strategy. A case study using the sun sail-shading strategy in El-Safwa School courtyard in Port Said, Egypt, is simulated during school time. Field measurements were conducted in specific locations in the courtyard. Microclimate models were simulated using ENVI-met V4.4.5 and Rayman 1.2 software. Several proposed cases have been studied based on the courtyard shading coverage ratio varying from 0% to 100% shaded with black sun sails. Hence, by adding 60% or above sun-sail shading in the school courtyard, the simulation results revealed a reduction in the air temperature (Ta), with an average difference of 0.5 °C, reduction in the average predicted mean voted (PMV) values above 0.6, and reduction in the mean radiant temperature (Tmrt) average values in most of the receptor points (approximately more than 20% reduction). The analyzed results of the physiological equivalent temperature (PET) and standard effective temperature (SET) showed the futility of using 40% sun sail-shading in the school courtyard, and the proper court coverage ratio to use is 60%.
The changing local climate in urban areas has raised concerns for monitoring and mitigating heating effects in built environments worldwide. The analysis of long-term temperature reveals that winter temperature has been increasing more than the summer temperature in the cities of India. Lack of strategic policies for urban heat island (UHI) mitigation in India makes the research in this field quite difficult. Although some studies have addressed the impacts of atmospheric pollution, aerosol optical depth, and greenhouse emissions on UHI, development of approaches to devise scientifically backed strategies and policies on urban areas is still missing. An effort has been made in the research presented int his chapter to suggest some techniques for UHI mitigation and climate resilient adaptation strategies befitting the tropical situation. The effects of vegetation and albedo enhancement on urban canopy environment have been examined through numerical simulation and evaluated in terms of the environmental attributes such as (1) air temperature (Ta), (2) human-weighted mean radiant temperature (MRTh−w), (3) wind speed, and (4) physiological equivalent temperature (PET) considered at a community scale. The effects of existing urban development on urban thermal heterogeneity have been assessed where the simulation results demonstrated the potential of mitigation strategies in ameliorating urban thermal conditions during a typical summer day. The simulation results point toward the strategic and policy-oriented measures need to be taken to mitigate the adverse UHI effects.
Energy poverty is defined as the condition in which low-income people is no more able to face the costs of energy bills and consequently accept to live in cold and uncomfortable houses. In recent years the scientific literature about this specific issue has registered a significant growth, despite the problem is mainly approached from an econometric point of view to which instead medical, social and energy aspects have to be coupled. Recent EU policies like the Clean Energy Package and the Energy Building Performance Directive Recast III encourage to increase the efforts to tackle and eradicate the energy poverty.
The paper approaches the problem focusing on one of its complementary causes: the building energy performance. The adopted methodology includes the calculation of the energy costs for each household, the definition of the energy poverty threshold, the calculation of the related building energy performance limit, otherwise leading to the energy poverty condition. These data, associated with the energy performance certificates, are used to create a GIS based mapping of the buildings potentially affected by energy poverty. Maps can be used to support decision making process in addressing appropriate strategies at urban level to tackle the energy poverty risk. The paper includes a case study in the city of Bologna where the proposed methodology is tested.
The awareness about environmental problems due to fossil fuel consumption is increasing widely; therefore, efforts are being made to develop energy-efficient and environmentally friendly systems by utilisation of non-polluting renewable energy sources. Ground source heat pumps (GSHPs) belong to this category. Many variations of geothermal system typologies exist, with different configurations suitable in different situations and most locations around the world. One emergent configuration is the solar assisted GSHP (SAGSHP). The paper focuses on different control strategies of a solar assisted ground source heat pump (SAGSHP) for different Italian locations. Dynamic simulation approach has been used through TRNSYS software. The impact of the considered strategies on the seasonal performance factor has been evaluated. Results have shown that the strategy affects strongly the system consumption; therefore, it needs to be chosen appropriately in the design phase. Furthermore when solar energy is driven into the ground, the temperature difference between solar collectors and the ground, which has to be a positive value to charge the ground, plays a fundamental role. In particular, solar thermal energy injected into the ground decreases to zero moving from a humid sub-tropical (Cfa) to a dry-summer subtropical (Csa) climate. Therefore, a compromise between the operation of the circulation pumps used for supplying free cooling energy and for driving solar thermal energy into the ground has to be found for each climate.
This paper focuses on parametric design-based visualization methods to represent building performance at the neighborhood scale in the perspective of an integrated design‑support system. The goal of the developed methodology is to convey the relative effectiveness of different design alternatives according to a wide range of building performance indicators, including the potential for active solar applications, the energy need for space heating/cooling and (spatial) daylight autonomy
The proposed methodology is applied to a case study of a typical urban renewal project in Switzerland for which several design variants were analyzed using validated climate‑based simulation engines. For each design variant, simulation results are represented qualitatively using multiple false-color maps and quantitatively through comprehensive plots.
We conclude by showing the applicability of this methodology to a large number of neighborhood-scale design variants as well as the complementarity of the proposed visualization methods. On the basis of the case study application, a possible implementation as a design-support tool is finally discussed.
The energy saving potential of existing buildings in highly urbanized world areas stimulates the interest for the introduction of renovation measures. Due to the high economic impact of those interventions, special attention has to be paid to balance energy and economic performance, leading to the definition of the best combination through multi-objective approach. The recourse to building simulation, to improve the resolution and discrimination capability between different renovation configurations, imposes to consider the quality of the input data and leads to robustness issues for the optimal solution. In this regard, a reliable estimation of the global irradiation incident on various tilted surfaces is essential in order to account for the solar heat gains. Nonetheless, many meteorological stations monitor only global solar radiation on a horizontal plane. As a consequence of that, a variety of mathematical and empirical models have been proposed in the literature for both the subdivision of horizontal solar irradiation into direct and diffuse components and for the calculation of irradiation on tilted surfaces. Besides introducing inter-model uncertainty, no pair of diffuse and tilt irradiation models can provide results with the same reliability for worldwide localities different from those considered for the definition of each model.
This research work investigates the extent to which the choice of solar irradiation models affects the confidence levels of the optimal solutions provided by multi-objective optimizations. With this purpose, several multi-objective optimizations are carried out with different solar irradiation models. Semi-detached houses penthouses and intermediate flat in multi-story buildings are analyzed with the purpose of broaden the representativeness of the conclusions.
The role of physical elements and interactions among them, which influence people behaviour and liveability conditions in urban spaces, is usually not correctly evaluated in environmental urban design in the Italian School of Architecture. The performance of basic physical elements in urban spaces – morphology, materials and the effect of environmental forces – are mainly designed to support functional and visual needs and requirements, while environmental comfort is often underestimated. Students attending the Master degree course "Environmental Design" at the Faculty of Architecture "Architettura e Società" -Polytechnic of Milan – implemented methods and tools to evaluate environmental performances in urban design, mainly focusing on thermal comfort needs. Some of these students use the same methodology for their thesis. This paper shows a work for a thesis describing four different squares in the dense central area of Milan having comparable characteristics such as morphology, e.g., shape and orientation materials. Microclimatic measurements have been done during a summer day, while comfort conditions have been calculated through the COMFA+ model.
The most important meteorological parameter affecting the human energy balance during sunny weather conditions is the mean radiant temperature T(mrt). It considers the uniform temperature of a surrounding surface giving off blackbody radiation, which results in the same energy gain of a human body given the prevailing radiation fluxes. This energy gain usually varies considerably in open space conditions. In this paper, the model 'RayMan', used for the calculation of short- and long-wave radiation fluxes on the human body, is presented. The model, which takes complex urban structures into account, is suitable for several applications in urban areas such as urban planning and street design. The final output of the model is, however, the calculated T(mrt), which is required in the human energy balance model, and thus also for the assessment of the urban bioclimate, with the use of thermal indices such as predicted mean vote (PMV), physiologically equivalent temperature (PET) and standard effective temperature (SET*). The model has been developed based on the German VDI-Guidelines 3789, Part II (environmental meteorology, interactions between atmosphere and surfaces; calculation of short- and long-wave radiation) and VDI-3787 (environmental meteorology, methods for the human-biometeorological evaluation of climate and air quality for urban and regional planning. Part I: climate). The validation of the results of the RayMan model agrees with similar results obtained from experimental studies.
Under the same urbanization pressure, the local climate in large metropolitan areas is also altered. This is especially apparent when certain climatic characteristics are considered, e.g. temperature, humidity and wind. In fact, all the main meteorological parameters are severely affected, resulting in the development of a local climatic regime, which is characterized by increases in temperature (the heat-island effect) and reduction of humidity and wind. Furthermore, in central areas particularly, the continuous replacement of vegetation with buildings and roads severely affects the radiation balance and this further influences the temperature regime of the environment. Under these circumstances the comfort index for those living in big cities is quite different from that for those living in suburban and rural areas.
Air-source heat pumps in heating mode are characterized by performances strongly dependent on the value of the outdoor air temperature. The Italian standard UNI/TS 11300-4 indicates, for the evaluation of a heat pump seasonal efficiency, a method based on the local bin distribution of the external air temperature. The aim of this paper is to test the bin-method proposed by UNI/TS 11300-4 by comparing the results obtained through this method with the results deducted by using a more accurate dynamic simulation of the system. The heat pump Seasonal Coefficient Of Performance (SCOP) is calculated by means of a dynamic simulation code, written in MATLAB, in which hourly climate data distributions defined by CTI for different Italian towns are introduced as input data together with the thermal characteristics of the building. The thermal winter behaviour of the building is introduced in the models by using the Building Energy Signature. In the paper the values of the seasonal indexes SCOPon and SCOPnet obtained by means of the bin-method and the dynamic hourly simulation, both for mono-compressor and inverter-driven heat pumps, in the service of several buildings placed in different Italian climates, are evaluated and compared to each other. Different buildings and different climate data are used in order to highlight the main conditions which are responsible of the difference between the predictions obtained with the bin-method and the results obtained by using the dynamic hourly simulation. The results reported in this paper put in evidence that the predictions of the bin-method tend to be in agreement with the results of the dynamic simulations based on the Test Reference Year only in particular conditions. The observed discrepancies in terms of SCOP between these two approaches can reach 23 %, varying with the climate data and with the type of heat pump considered.
In the present paper a computational methodology for assessing and improving the microclimate in the urban environment is developed. A Computational Fluid Dynamics (CFD) model is described, which accounts for the evaporation occurring on water surfaces as well as the evapotranspiration from plant surfaces and tree foliage. Solar radiation and wind effects are also taken into account. Additionally, thermal comfort indices are implemented in the model, hence local information is provided regarding thermal sensations (bioclimatic maps). Surface temperature and air temperature at pedestrian level, are also used to characterize the microclimate. The methodology is demonstrated by means of a case study, which refers to the area of Gazi in Greece. Initially, the model is applied for simulating the airflow pattern throughout the domain of interest. The numerical results reveal the problematic areas in terms of thermal discomfort and wind effects. Based on that information advanced bioclimatic techniques are suggested to reduce severe heat stresses and to eliminate these areas. The effectiveness of the architectural interventions is tested by estimating the microclimate-indices differences compared to the existing conditions. It is concluded that the proposed methodology serves adequately for applying effective bioclimatic strategies to mitigate the Urban Heat Island (UHI) effect.
RUROS -Rediscovering the Urban Realm and Open Spaces
- Cres
CRES. 2004. RUROS -Rediscovering the Urban
Realm and Open Spaces. CRES (Centre for
Renewable
Energy
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Buildings
Department,
2004,
ISBN:
960-86907-2-2,
http://alpha.cres.gr/ruros