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Summer Thermal Comfort in Architectural Early Design Workflows

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Abstract. In recent years, to decrease greenhouse gas emissions as a part of climate change mitigation strategies, adoption of passive house approach, which is amongst the most prominent due to high energy efficiency potential, has gained momentum especially in Europe. On the other hand, global warming of 1.5°C and 2°C is expected to be exceeded during the 21st century and this opens a debate on the summer thermal performance of passive houses. Architects, as main actors of the design process, play a significant role for the early assessment of potentials and risks regarding the building performance. Nevertheless, the use of performance assessments in design workflows is not main stream among architects yet. At this point, for architects to be able to include performance evaluations in their workflows, simplified performance assessment methods and building performance simulation tools integrated with design tools become more significant. In this regard, this study presents a simplified thermal performance evaluation method through a systematic performance simulation in early design phase. To meet the indoor thermal comfort expectations, temperature is one of the key parameters in building design and intensively correlated with the carbon footprint in the use phase. Therefore, thermal comfort is selected as the main performance topic, and a simplified method, namely annual neutral hours, which refers to the capacity of a building to run without active heating and cooling, is presented. In this scope, the paper discusses summer thermal comfort and climate change over a residential building case study by using a Building Performance Simulation tool integrated into a 3D CAD design tool. The results indicate that the proposed methods are applicable to early design workflows and have a potential to give insight to architects by enabling quick and iterative evaluations for the detection of key parameters; thus, solution alternatives. As an additional result of the study, among other parameters, transparent envelope properties and shading elements appear to be significant to meet the expectations for future summer thermal comfort; also, it is seen that the winter performance might slightly benefit from the climate change.
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RESEARCH ARTICLE | NO VE MB ER 0 9 20 23
Summer thermal comfort in architectural early design
workflows
Isil Kalpkirmaz Rizaoglu ; Karsten Voss
AIP Conf. Proc. 2918, 020029 (2023)
https://doi.org/10.1063/5.0171066
11 November 2023 18:02:59
Summer Thermal Comfort in Architectural Early Design
Workflows
Isil Kalpkirmaz Rizaoglu1, a) and Karsten Voss1, b)
1Chair of Building Physics and Technical Services, Faculty of Architecture and Civil Engineering, University
Wuppertal, Pauluskirchstraße 7, 42285 Wuppertal, Germany
a)Corresponding author: kalp@uni-wuppertal.de
b)kvoss@uni-wuppertal.de
Abstract. In recent years, to decrease greenhouse gas emissions as a part of climate change mitigation strategies, adoption
of passive house approach, which is amongst the most prominent due to high energy efficiency potential, has gained
momentum especially in Europe. On the other hand, global warming of 1.5 °C and 2 °C is expected to be exceeded during
the 21st century and this opens a debate on the summer thermal performance of passive houses. Architects, as main actors
of the design process, play a significant role for the early assessment of potentials and risks regarding the building
performance. Nevertheless, the use of performance assessments in design workflows is not main stream among architects
yet. At this point, for architects to be able to include performance evaluations in their workflows, simplified performance
assessment methods and building performance simulation tools integrated with design tools become more significant. In
this regard, this study presents a simplified thermal performance evaluation method through a systematic performance
simulation in early design phase. To meet the indoor thermal comfort expectations, temperature is one of the key parameters
in building design and intensively correlated with the carbon footprint in the use phase. Therefore, thermal comfort is
selected as the main performance topic, and a simplified method, namely annual neutral hours, which refers to the capacity
of a building to run without active heating and cooling, is presented. In this scope, the paper discusses summer thermal
comfort and climate change over a residential building case study by using a Building Performance Simulation tool
integrated into a 3D CAD design tool. The results indicate that the proposed methods are applicable to early design
workflows and have a potential to give insight to architects by enabling quick and iterative evaluations for the detection of
key parameters; thus, solution alternatives. As an additional result of the study, among other parameters, transparent
envelope properties and shading elements appear to be significant to meet the expectations for future summer thermal
comfort; also, it is seen that the winter performance might slightly benefit from the climate change.
INTRODUCTION
In an earlier paper [1], authors shared an extensive literature review on the potentials and the barriers of integration
of building performance analysis into early architectural workflows. One of the main findings was that simplified
building performance methods and Building Performance Simulation (BPS) tools adopted in a design ecosystem have
a significant potential for this integration. In early design investigations, less complex and less time-intensive
performance analyses are more likely to be adopted by larger number of architects, because early design seeks
detection and quick evaluation of possible design alternatives in relatively short time and with relatively less input.
Some others [2] say that: “In many cases simulation only needs to be adequate for comparative analysis of design
variants.and “Although design parameters have to be considered in an integrated manner, different design stages
focus on different parameters. However, the previous study [1] indicated that most of the available building
performance methods and tools are too advanced and too time intensive to be adopted in early design. Extensive
building data and level of knowledge that are required to use advanced BPS tools; file exchange between standalone
BPS and design tools, which is prone to data loss; non-architect-friendly user interfaces with numeric inputs appear
to be important drawbacks. Therefore, for adoption of performance analysis in early design phase, there is need for
more methods with an adequate level of precision for early design performance analysis.
5th Central European Symposium on Building Physics 2022 (CESBP 2022)
AIP Conf. Proc. 2918, 020029-1–020029-9; https://doi.org/10.1063/5.0171066
Published by AIP Publishing. 978-0-7354-4734-9/$30.00
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11 November 2023 18:02:59
Thermal comfort is selected as the main topic of performance analysis, for temperature is one of the key parameters
in building design to meet the indoor thermal comfort expectations and intensively correlated with the carbon footprint,
and accordingly with the energy use. And a simplified method, namely annual neutral hours, which refers to the
potential of a building or a zone - to run fully passive, is presented. Energy efficiency in buildings is amongst the
economically most interesting options for the reduction of greenhouse gas emissions. So-called Passive Houses have
proven to be able to reduce the heating demand of buildings in central European climates by app roximately 90% as
compared to the existing building stock [3]. The five basic principles of any building with passive house approach are
excellent thermal insulation; avoidance of thermal bridges; low window heat losses; a very tight building envelope;
and a ventilation system with highly efficient heat recovery. All principles are mainly based on conservation of energy
gained from people, lighting, household appliances and additionally from solar radiation, by balancing heat losses.
Many authors discussed the energy and comfort issues of Passive Houses and other low energy building approaches
through the case studies in North [4, 5], Central [6, 7], and South [8, 9] Europe, as well as in world-scale [10,11]. The
literature signifies an overheating risk, especially in southern Europe, which is the phenomenon of excessive high
temperatures, resulting from internal or external heat gains, that may have adverse effects on the comfort, health or
productivity of the occupants [12].
Another finding of the literature review is that the vast majority of these studies are carried out by simulation
experts through application of complex assessment methods and specialized BPS tools, as a separate task from design.
However, as mentioned earlier, the use of performance analysis by architects at the earliest possible stage is a very
promising way to detect risks - in this case: overheating - and thereby to achieve a high-performance built environment.
Therefore, this study presents a thermal performance evaluation integrated in architectural early design workflow. In
this scope, it discusses summer thermal comfort and climate change over a residential building case study by using a
BPS tool within a 3D CAD design tool. Besides that, parametric modeling and simulation technics, which allows fast
and automated generation of design variants, as well as optimization, to find well-performing variants based on
performance goals, are used. To investigate this topic, one location - Wuppertal - is selected from Central Europe,
where first examples of passive houses stem from; and one location - Istanbul - is selected from southern Europe with
warmer climate. Research starts with the question: “How useful is a thermal performance evaluation method that is
relatively simplified and integrated into the architectural early design workflow?”. And via the proposed method, it
tries to answer the questions: “How critical is the future summer thermal performance, considering climate change?”
and “How does the significance of the key parameters change according to the climate pattern?”.
METHODS
Location and Weather Data
(a)
(b)
FIGURE 1. Istanbul and Wuppertal on map (a). Comparison of Wuppertal and Istanbul for present and future climate scenarios
in terms of monthly average outdoor dry bulb temperature Future scenario is based on IPCC Scenario A2 for 2100 (b).
Wuppertal from Northwest of Germany, has a temperate climate without dry season according to Koppen Climate
Classification; Istanbul from Northwest of Turkey, similarly has temperate climate, but differently with dry and hot
summers [13]. For the representation of the climate pattern of Wuppertal, Typical Metrological Year (TMY) weather
data of Dusseldorf (World Meteorological Organization (WMO): 104000, Latitude °N: 51.283, Longitude °E: 7.767)
is used. For Istanbul (WMO 170620, Latitude °N: 40.967, Longitude °E: 20.083) also TMY weather data is used.
Present weather data sets are provided by Meteonorm [14], which is a meteorological database and a calculation tool.
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Future weather data sets are created via the database based on Intergovernmental Panel on Climate Change (IPCC)
high emission scenario A2 [15] for the year 2100. When the present and future monthly average outdoor temperatures
are compared (see Fig. 1), it is seen that expected increase in Istanbul (2.8 °C) is higher than Wuppertal (2.0 °C).
Site Context and Building Typology
Dwelling typology has been shown to have a significant effect on both heating demand and overheating risks. In
comparison to detached dwellings, compact dwelling formats (with reduced external surface areas) are likely to have
lower heat losses in winter, but conversely may be prone to greater summer overheating risks due to less ventilation
openings [7]. That being the case, hypothetical 5 storey residential building is assumed as a filling mass in an existing
urban context. And 100 m2 middle floor (see Fig. 2), which is likely to have less heat transmissions, for the upper,
lower, and two-side closures are adiabatic, is selected as a unit for simulations.
Original orientation of the unit in the real site context,
which is Southwest Northeast direction, is remained,
because it is in accordance with the aim of testing the
overheating risk, for the Southeast façade is exposed to late
noon and afternoon radiation, when the ambient
temperatures peak. Low slope of the topography, which is
5%, is dismissed, and the building is assumed to sit on a
horizontal plane. Rest of the site related features remain as
it is; i.e. vegetation and surrounding buildings.
FIGURE 2. Site plan
Modeling, Simulation and Optimization Tools
ClimateStudio [16], which is an environmental performance analysis plugin for Rhinoceros3D computer-aided
design (CAD) software [17], is used for the dynamic thermal comfort simulation. ClimateStudio is built on the
validated simulation engines EnergyPlus and Radiance, and well-integrated in Grasshopper [18], which is a graphical
algorithm editor in Rhino 3-D modeling tool and enables coupling number of tools for modeling, parametrization,
simulation and optimization. Model-based optimization tool Opossum [19], which is a plugin for Grasshopper, is used
for multi objective optimization (MOO). Please see Fig. 3 for Tools and workflow.
FIGURE 3. Tools and workflows used in the study.
Base-Case Simulation Model and Settings
The base-case thermal model is created by defining the middle floor of the 5-storey residential building without
active heating and cooling as a single-zone. The zone model has two façades with 3 m × 10 m dimensions, facing
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Southwest and Northeast orientations; 100 m2 floor area; and 4 adiabatic envelope elements, i.e., upper, lover and two
side closures (see Fig. 4).
(b)
(c)
FIGURE 4. Single zone model (a), floor layout (b) and South perspective of the zone (c)
Base-case single zone model settings are defined highly consistent with passive house planning principles [20]
(Table 1). Infiltration by air leakages is assumed to be nonexistent to avoid inconsistency that might arise from
different climate patterns, e.g. wind speeds. Zone is assumed to be thermal bridge-free. Also effect of window frames
are not included, assuming that thermal properties of glazing unit are extended across the rough opening of the
window. Natural ventilation scenario is based on bouncy. Set point, which is the indoor temperature, at which the
windows open for natural ventilation, is defined as 24 °C. To avoid extreme temperature effect of the outside air, min
outdoor (Tout, min) and max outdoor (Tout, max) temperatures are set as 5 °C and 26 °C, at which the windows close.
Mechanical ventilation with a sensible heat recovery of 85% is set only for fresh air. By the literature, it is seen that
Passive House case-studies mostly use default occupant density of 35 40 m2 per person (m2/p). For this study,
considering the urban context and future population trends, occupancy density is assumed as 30 m2/p. Metabolic rate
(met) is defined as 1.2, which refers to “standing at rest” activity by a gain of 70 W/m2 per person. Internal gains from
appliances and lighting are considered. Some of the optical and thermophysical properties of the envelope, internal
gains and façade related geometric parameters are further investigated for future climate scenarios (Table 2).
TABLE 1. Base-case Settings
Site Context
Surrounding Buildings and Vegetation
Model
Single Zone
Use
Residential - Multi-Family Apartment - Attached
Loads
People Density: 30 m2/p
Metabolic Rate (met): 1.2 (70 W/m2 per person)
Internal Gains (Equipment and Lighting): 2.1 W/m2
Cond.
No Heating
No Cooling
Humidity Control: min. Relative Humidity 20% - max. Relative Humidity 60%
Mechanical Ventilation with Heat Recovery (Sensible): 85% only for fresh air: 40 m3/p/h
Heat Recovery (Sensible): 85%
Natural Ventilation: Only "Buoyancy" Driven
Natural Vent Control: Set Point: 24 °C, Min. & Max. Outdoor Temp.: 5 °C & 26 °C
Domestic Hot Water Flow Rate: 1.7 l/h/p
Envelope
Opaque: U-Value: 0.15 W/(m2K); Heat Capacity: 270 kWh/(m2K); Wall Thickness of 0.33 m.
Transparent (Glazing): U-Value: 0.77 W/(m2K); SHGC: 0.521; Tvis: 0.546)
Window Frame: U-Value: 0.77 W/(m2K); SHGC: 0.521; Tvis: 0.546)
Glazing Ratio: 20% on Both Facades (Northeast and Southwest)
Air Tightness: Leakage Free
Thermal Bridges: Bridge Free
Shading: No (Except the Effect of Wall Thickness)
The Passive House Planning Package uses a default value of 2.1 W/m2 for internal (lighting & equipment) gains,
also a value of 2.6 W/m2 to asses summer overheating risks [3]. Additionally, assuming that in the future, household
equipment is likely to be more energy efficient, but on the other hand, there may be more equipment in one household
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for they will be more affordable, 4.2 W/m2 is set as the third variable in this investigation. Shading variations and
active cooling are tested only for the Istanbul case.
TABLE 2. Investigated key parameters
Envelope optical & thermo physical parameters
Geometry related parameters
Opaque U-Value (0.15; 0.20; 0.25 W/(m2K))
Façade Glazing Ratio (Range: 20100%)
Glazing U-Value (0.77; 1.44 W/(m2K))
Window Overhang Depth (Range: 01.2 m)
Solar Heat Gain Coefficient (0.52; 0.64)
Hybrid Shading (Overhang and Side Fins) Depth (Range: 01.2 m)
Specific Heat Capacity (Light: 90, Medium:180,
Heavy: 270 kWh/(m2K)
Movable Shading Exterior Blinds (Different Control Strategies)
+ Internal Gains (2.1; 2.6; 4.2 W/m2)
Simplified Thermal Comfort Indicator: Annual Comfort Hours (%)
In this study, percentage of heating, cooling and neutral hours are used as an indicator of thermal comfort
performance. Neutral hours temperature with the range of 6K [21], which refers to normal levels of expectation and
is considered appropriate for new buildings and renovations, is taken. Hours equal to and between 20 °C and 26 °C of
operative temperature (Top) are considered as neutral hours”, which refers to the capacity of a building to be run
without active heating and cooling. Neutral hours is more of a simplified approach to give architects an insight
about thermal comfort, rather than a definitive method of a building's cooling and heating demand. It should be noted
that based on a design - e.g. use, user profile and comfort expectation - the range and the limit values of “neutral
hours” are prone to change.
Thermal comfort indicators are used as a percentage of 8760 hours: heating hours (%) (T operative < 20 °C),
neutral hours (%) (20 °C ≤ T operative ≤ 26 °C), cooling hours (%) (T operative > 26 °C). Cooling hours higher than
10% of the occupied time are assumed to be demonstrating a need of active cooling. Threshold for cooling hours is
set as 10% of the occupied hours, for the occupancy is continuous in the study, 10% of occupied hours refers to 10%
of the 8760 hours.
RESULTS AND DISCUSSION
Performance assessment starts with base-case simulations, which are run for the selected locations considering
both present and future climate data to establish a ground for parameter studies. It is clear that Istanbul is more sensitive
to climate change impact (Fig. 5). While cooling hours increase from 1% to 4% in Wuppertal, the increase in Istanbul
is from 14% to 27%.
FIGURE 5. Comparison of Wuppertal and Istanbul base-case thermal comfort for present and future climate scenarios
Opaque and Transparent Envelope Properties
First parametric investigation is conducted by combining envelope optical & thermophysical parameters. Nine
different building envelopes are defined by combining 3 different U-values with 3 different specific heat capacities.
Later, these variations are combined with 2 different glazing types (please see Table 2 for the values of investigated
parameters.). Thermal comfort results according to the envelope properties can be seen below (Fig. 6 and Fig. 7): 18
combinations, which are envelope types (C1 - C18) [Triple Glazing (TG) and Double glazing (DG)], are investigated
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for each location for future climate. It is seen that while best performance for Wuppertal - heating hours 41.6%, neutral
hours 54.2% and cooling hours 4.2% - is reached by the envelope 1 with high insulation, heavy mass and triple glazing
(C5) (Fig. 6). For Istanbul, although the lowest cooling hours are reached by the same combination of the envelope 1
(C5), highest neutral hours are reached by light mass variation of the envelope 1 (C1) (Fig. 7). This result is likely due
to lower temperature fluctuations in Istanbul during the Winter. Nevertheless, further investigations are needed for
Istanbul, because it is far beyond the summer thermal comfort threshold.
FIGURE 6. Wuppertal - Future thermal comfort investigation with envelope properties
FIGURE 7. Istanbul - Future thermal comfort investigation with envelope properties
Internal Gains
Second parametric investigation is done to see the effect of internal gains. For each location, keeping the rest of
the base-case settings same, internal gain values of 2.1; 2.6; 4.2 W/m2 are tested. Compared to summer comfort,
internal gains have higher effect on winter thermal comfort for both climates. When the internal gains increase from
2.1 W/m2 to 4.2 W/m2, heating hours in Wuppertal decrease from 42% to 37% and in Istanbul from 22% to 16%. On
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the other hand, cooling hours slightly increase in both climates, so this results in larger amount of neutral hours in
both climates - neutral hours increase from 54% to 58.5 % in Wuppertal and 51% to 56% in Istanbul.
Glazing Ratio with Different Glazing Types
To investigate the impact of the glazing ratio, future base-cases are simulated by application of double and triple
glazing types: 4 optimizations with 50 iterations are run for each test case. Maximum neutral, minimum cooling and
heating hours are set as objectives and glazing ratio of the Southwest façade with the range of 20% to 99% as a
parameter. For Wuppertal case with triple glazing, the glazing ratio of 86% is found to be an optimum with maximum
neutral hours of 60.7%. Relatively medium level of solar heat gain coefficient (SHGC) of 0.52 and high performance
of U value of 0.77 W/(m²K) of the triple glazing, also relatively low future solar radiation in Wuppertal climate should
be considered for the interpretation of the results. When the glazing ratio increases from 20% to 86%, cooling hours
increases from 4.2% to 8.5%, and heating hours decreases from 41.7% to 30.8%. This shows that cooling hours is
more sensitive to glazing ratio in the scope of this example. For Wuppertal case with double glazing (SHGC of 0.64
and U-value of 1.44 W/(m²K)), the ratio of 58% is found to be an optimum with maximum neutral hours of 58.4%. In
Wuppertal, with slightly higher neutral hours, the triple glazing has a slightly higher potential than double glazing.
For Istanbul case with triple glazing, rather than a single value, a range of 64% and 89% shows the similar
performance for neutral hours of 59.4%, while cooling hours slightly swing around the value of 31.5%, and heating
hours around the value of 9.1%. This can be interpreted as a result of a climate pattern almost equally dominated with
heating and cooling demands. Approximately same amount of neutral hours of Wuppertal, i.e. 60%, is reached with
lower glazing ratios. With double glazing, also a range of 57% and 72% glazing ratio is found to be an optimum with
maximum neutral hours of 56.3%. While the triple glazing has again slightly higher potential with slightly higher
neutral hours in Istanbul, the optimized glazing ratios result in high level of cooling hours, approximately 30%. This
investigation shows that optimum glazing ratio is highly dependent on the selected glazing type, as well as the climate.
Shading
While Wuppertal case fulfills the summer thermal comfort requirement, Istanbul case needs further investigations.
Therefore, structural (i.e., overhangs & fins) and moveable (i.e., automated exterior blinds) shadings are evaluated for
Istanbul case. Structural shading investigation of the overhang depth for a range of 0 1.2 m (+ wall thickness
0.33 m) shows that the depth and heating hours increase parallelly, but comfort hours do not improve due to lower
rate of decrease in cooling hours (Fig. 8a). For the same range, hybrid shading (the combination of overhang and side
fins) investigation shows similar pattern, but compared to overhangs, increase of hybrid shading depth results in higher
decrease in neutral hours (Fig. 8b).
(a)
(b)
FIGURE 8. Future thermal comfort investigation for Istanbul with overhang (a) and hybrid shading (b) depth of Southwest
façade with triple glazing glazing ratio 64% on SW and 20% on NE
Automated exterior blinds with 0.5 transmittance and with different control strategies, is evaluated. It is seen that
the control strategy with outdoor temperature (20 25 °C tested) performs better than the control strategy with solar
radiation (150, 180, and 250 W/m2 tested) on a window surface. The solar control decreases the cooling hours from
30.4% to 28.9% (1.5% point), increases the heating hours 4.2% points. But the temperature control improves the
whole thermal comfort by decreasing both heating and cooling hours, as well as increasing the neutral hours 3.5%
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points. Considering Istanbul climate with medium level of annual sky openness factor - approximately 0.50 - and
relatively high outdoor temperatures, these results are reasonable. Nevertheless, although the neutral hours are
increased to 62.2% by the blinds with outdoor temperature control, cooling hours still remain over the limit value.
Active Cooling
Active cooling is tested, as the Istanbul case could not meet the summer thermal expectations. Best performing
passive variation from previous investigation - with 10.1% heating, 62.2% neutral and 27.7 % cooling - is taken as a
base model. Energy use intensity of this variation related to lighting, equipment and domestic hot water is
26 kWh/(m2yr). When the cooling is set on, it brings extra demand of 34 kWh/(m2yr), and total energy use reaches
60 kWh/(m2yr). With active cooling, the requirement is fulfilled - with 5.3% of cooling hours and 84.6% of neutral
hours.
CONCLUSIONS
This study shows that simplified performance indicators and BPS tools integrated in architectural design
workflows show a promising potential for early assessments by architects. In the scope of this study, key parameters
are successfully detected and in total 291 variable combinations for the selected parameters were tested just in
architectural design ecosystem to inform early design phase. Parametrization and optimization techniques were the
unique catalyzers for speeding-up and supporting the decision making. Although these techniques require a certain
level of knowledge, they make the investigation space larger and less time consuming for exploration. The limitation
of applying BPS in early phase was the uncertainties stemming from the phase, but custom templates were helpful.
Acknowledging the necessity of simplifications for early design phase, it is important to understand pros and cons of
these simplifications, to be able to decide when to employ them and when to turn to more advanced methods and tools.
For instance, it was important to consider the risk of the accumulation of comfort hours just behind the limit
temperatures; and to check the operative temperature curve graphics. Considering results of case studies, this research
confirms that buildings in warmer climates are likely to result in low summer thermal comfort. Nevertheless, there is
not one-way ready-recipe, and the significance of the parameters highly depends on site, climate, also on architectural
design goals and priorities. Combinations of glazing types and glazing ratio appears to be significant for both locations.
It is observed that while thermal mass is more critical in Wuppertal with relatively high temperature fluctuations;
external shading plays more important role in Istanbul with higher temperatures. The summer thermal comfort in
Istanbul is likely to be much lower and unlikely to be achieved without an additional cooling system. In general, this
case study results support that simplified thermal performance evaluation methods integrated in architectural early
design workflows can perform as adequately as complex methods, considering the investigation phase.
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Presentation at the International Conference of Building Simulation 2021, Bruges, Belgium.
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The increase in population and living standards, as well as global warming and heatwaves due to climate change, have created a challenge to meet the cooling demand in buildings. In this study, the cooling requirement for a multifamily building through simulations in a future city district in central-Sweden was determined. Different air supply set point strategies, window to floor ratio and building rotations were employed to minimize the cooling requirements. The building was modelled so as to meet the Nearly Zero Energy Building (NZEB) requirements. Window to floor ratio of 10% with a piecewise proportional controller for supply temperature was depicted as appropriate for the building. A 45° rotation of the building increased the cooling demand. The cooling demand of the building increased by employing the extreme climate condition, as a representative for future climate, with factors 3.8 and 6.4 for cooling set points 25°C and 27°C for window to floor ratio 10%. This implies the need for a resilient building to withstand future climate conditions. The requirement to update the climate files was also used for decision making in the design process and building regulation.
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Model-based optimization is an innovative optimization strategy and particularly appropriate for time-intensive performance simulations. To demonstrate this appropriateness, the paper reviews simulation-based optimization algorithms and benchmarks several (single- and multi-objective) optimization tools on two problems involving annual daylight and glare simulations. The benchmarks demonstrate that model-based optimization outperforms other (single- and multi-objective) approaches on time-intensive, simulation-based optimization problems and thus puts new applications within reach. In this way, model-based optimization aids architectural designers and consultants to develop more resource and energy-efficient buildings.
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In response to UK government policy Mandating the construction of 'zero carbon' homes by 2016 there have been significant changes in the way dwellings are being designed and built. Recent years have seen a rapid uptake in the adoption of the German Passivhaus standard as a template for ultra-low energy and zero carbon buildings in the UK. Despite genuine motivations to mitigate climate change and fuel poverty there is a lack of research investigating the long-term performance of Passivhaus buildings in a rapidly changing UK climate. This paper sets out to investigate whether Passivhaus dwellings will be able to provide high standards of thermal comfort in the future or whether they are inherently vulnerable to overheating risks. Scenario modelling using probabilistic data derived from the UKCP09 weather generator (WG) in conjunction with dynamic simulation and global sensitivity analysis techniques are used to assess the future performance of a range of typical Passivhaus dwellings relative to an identical Fabric Energy Efficiency Standard (FEES) compliant dwelling over its notional future lifespan. The emphasis of this study is to understand what impact climate change will pose to overheating risks for Passivhaus dwellings relative to the de facto (i.e. FEES) alternative, and which design factors play a dominant role in contributing to this risk. The results show that optimization of a small number of design inputs, including glazing ratios and external shading devices, can play a significant role in mitigating future overheating risks.
Conference Paper
Changing needs and expectations in architecture practice, not only regarding environmental issues, but also the technological advancements, requires a shift in the way the Building Performance Simulation (BPS) is used. Although it is widely acknowledged that integration of BPS with the early phase of architectural design is quite critical, BPS is still not an inherent part of it. In response, this paper aims to explore the potentials and the barriers by a comprehensive literature review. Correspondingly, the results of survey "BPS in Teaching" and a prototype for performance-based design and simulation environment are presented.
Article
Passive Houses are buildings which provide comfortable indoor conditions at an extremely low heating and cooling load. The peak daily average heating and cooling loads are typically below 10 W/m2 and annual useful energy demands are below 15 kW h/(m2 a). The Passive House standard was originally developed in Germany. In this paper we show by hygro-thermal dynamic simulation that it is possible to realize residential Passive Houses in all of the world's relevant climate zones, represented here by Yekaterinburg, Tokyo, Shanghai, Las Vegas, Abu Dhabi, and Singapore. The window quality, insulation levels, and mechanical services all depend on the climate as well as on the building's shape and orientation. The resulting annual energy demand for space conditioning of the Passive Houses is 75 to 95% lower than that of a traditionally insulated building of the same geometry. In humid climates like Shanghai or Singapore, special attention must be paid to humidity aspects. In climates which are hot and humid all year long, the total useful energy demand for sensible and latent cooling may exceed 70 kW h/(m2 a) even in a Passive House. Finally, it is shown that the architectural quality is not compromised by the Passive House requirements.