Discomfort Hours Research Articles

Exploring double skin façade as strategy for achieving thermal comfort in proposed mixed use office complex Kano, Nigeria

Thermal comfort can be defined as a state of mind which a human feels neither too hot nor too cold. Thermal discomfort in the case of hot humid climates, becomes a great threat to our livelihood and thermal comfort in offices in general. The ability of designers to harness and use the building envelope make life much better and livable is of great importance. This research seeks to use Double skin façade as a strategy for improving indoor thermal comfort by testing the air gap between the double skins. Climate and Weather readings were obtained and used to simulate and check the effect of Double skin façade in improving indoor thermal comfort in office complex. Double skin facade has been suggested by many researchers as a possible alternative technique for improving indoor thermal comfort. The double skin facade study in this research involved computer simulation using Emissions Control Optimization TEChnology (ECOTEC). The result of the final base case model shows that double skin façade can increase the indoor thermal comfort in a building and the wider the air gap, the higher the thermal comfort by showing the hours of comfort and discomfort to the simulated office building. The other important factor is that it can continuously induce the flow of natural ventilation, regardless of the available wind outside of the office complex building. This effect is significant toward improving the thermal comfort performance in the office complex through passive natural ventilation.

Energy and thermal performance of a typical rammed earth residential building in Western Australia

Rammed earth (RE) constructions are gaining relevance worldwide for their reduced embodied energy when local materials are employed, and the material is stabilised with sustainable stabilisers or with a low quantity of cement. Besides, RE construction offers good thermal performance under specific climatic and technical conditions. However, the material is characterised by poor thermal resistance, which led to the common practice of insulating RE walls. This study focuses on the effect of including natural fibres (Spinifex) on the thermal properties of cement stabilised RE made of crushed limestone. This study integrates an experimental approach investing the thermal properties of RE with a building dynamic simulation approach employed to assess the energy performance of a typical residential building against the Australian National Construction Code’s requirements. The thermal performance of the building is assessed under different climate-specific adaptive thermal comfort models regarding the Western Australian climates. The results show that the inclusion of Spinifex fibres positively affects the material's thermal properties. Besides, the study illustrates a considerable difference in the evaluation of the discomfort hours when climate-specific models are adopted compared with internationally accepted standards.

Design optimization of rural building in dry-hot and dry-cold area using a back propagation (BP) neural network

This study describes the numerical analyses of the indoor air temperature of the earth building located in dry-hot and dry-cold area in order to evaluate the effects of the passive design parameters on the indoor environment and then determine the optimal values of the design parameters. Firstly, a short-term monitoring was performed in an existing earth building, aiming to validate the numerical building model developed by using an advanced simulation software EnergyPlus. Then a series of regional studies on the effect of building parameters on indoor environment of the earth building were investigated and the simulated results indicated that four design parameters, i.e. building orientation, window to wall area ratio, projection factor of window shading and external wall thickness, exhibit the distinctly impacts on the indoor thermal environment in winter and summer. Next, a back propagation (BP) neural network model with ten neurons in the hidden layer was established using Matlab R2016a to predict the indoor environment, and the degree discomfort hours (DDH) in winter and summer were calculated as the output data. Finally, the itemized intensive scanning technique was used to successively select the values of the passive parameters in their range and the predicted results indicated that the optimal passive parameters are 6°east of south, 18.20 %, 0.66 and 643 mm, respectively.

Effects of Climate Change on Thermal Comfort and Energy Demand in a Single-Family House in Poland

In regions with temperate climates, the thermal insulation of buildings is increased to reduce the need for heating. It might significantly reduce human thermal comfort in the summer period. The problem can increase with global warming. The aim of the paper is to analyze the heating and cooling demand, as well as thermal comfort in a single-family house located in Poland for three climate scenarios (typical, real, and future weather data) and for two types of thermal insulation of external walls. In the study, two ways of cooling the building were taken into account: using split air conditioners and using fresh airflow provided through the opening of windows. The open area and the temperatures for opening windows have been optimized using a two-criteria function. The energy simulation was carried out in EnergyPlus 9.4 software. The multi-zone model was validated on the basis of the temperature measurement. The results showed that there will be a problem with ensuring thermal comfort in the future, especially in well-insulated buildings. The energy demand for cooling will be greater than the demand for heating. The use of passive cooling is a good solution for residential buildings in these regions, and the number of discomfort hours is small (max 5%).

Energy and Environmental Effects of Human Habits in Residential Buildings Due to COVID-19 Outbreak Scenarios in a Dwelling near Rome

The COVID-19 pandemic and resulting containment measures have shown that energy consumption in buildings is linked to several factors, such as living habits, occupancy profiles, and heating ventilation and air conditioning (HVAC) systems. This paper addresses the influences of such factors on energy consumption in a residential building, analysing different scenarios (pre-COVID-19, lockdown, post-COVID-19), in terms of discomfort and energy needs, through the new hourly calculation method (UNI EN ISO 52016). Energy and environmental effects were studied in a real case study near Rome by varying occupancy profiles, lighting and appliance schedules, and HVAC systems. Results show that, during the heating period, the lockdown scenario led to the lowest hours of discomfort (−29% on average), but the highest in the cooling period (up to +154%, +28% on average). The same scenario led to reasonable reduction of energy needs for heating (−14%), but also highlighted a significant increase (+60%) for the cooling period. This study underlines how the pandemic has influenced the energy and environmental behaviours in buildings. Moreover, the new hourly calculation method points out the importance of analysing HVAC systems, in terms of hours of discomfort, which could provide results that are more reliable.

Compressed stabilized earth block: environmentally sustainable alternative for villages housing

Construction materials contribute to environmental pollution and the impoverishment of natural raw materials. The villages of Upper Egypt were exposed to high thermal loads owing to their geographical location. Moreover, the current building materials do not comply with the principles of sustainability and environmental adaptation of the residents of these buildings. Therefore, attaining admission to one sustainable building material in Upper Egypt and using it as an environmentally compatible, inexpensive, accessible, and easy building material for the users of these blocks is essential. In this study, the author selected various sites in Upper Egypt, analyzed climate and urban data, and after that, suggested prototypes with many variables and measured using the DesignBuilder V5 computer simulation program to select an optimal building type. Reached that can be saved energy about 40:50% and decreased annual discomfort hours more than 50%, finally, discussed with community members by a questionnaire on societal acceptance. The research concluded that building with compressed stabilized earth block is an environmentally sustainable solution applied in residential areas in the villages of Upper Egypt to reduce deficiencies in environmental adaptation.

Towards Passive Design Strategies for Improving Thermal Comfort Performance in a Naturally Ventilated Residence

Passive design integrates a wide range of climate-based strategies to increase occupant thermal comfort and minimise the need for mechanical systems for heating and cooling. The aim of this study was to improve the thermal comfort performance in a naturally ventilated residence through the identification and evaluation of the best set of passive design strategies. A two-storey residence located in Washington, United States with a temperate climate was selected as the case study residence. A reference simulation model was developed by replicating only the orientation and massing of the case study residence, while certain assumptions were made for other building characteristics. Thermal comfort performance analysis was conducted in the DesignBuilder software. A set of design strategies were introduced as interventions followed by simulation runs to efficiently track progress. From the reference simulation model to the final intervention model, a 50% reduction in the annual discomfort hours was anticipated in the five selected zones of the residence. Following the integration of four major interventions, the target discomfort hours were met in three zones—library, bedroom 1 and bedroom 2, with 53.03%, 60.42% and 58.94% reduction in discomfort hours, respectively. The two remaining zones—living and lounge also had a notable improvement with a reduction of 43.93% and 45.99%, respectively. The successful design strategies included—incorporation of triple glazed, low-emissivity and argon filled openings with wooden frames; integration of overhangs in south-facing windows, minor reduction of openings in the east and west façade, and addition of blinds for window shading; and use of an energy code standard construction for the building components and further addition of insulation in the building envelope. The most effective intervention was the customisation of the window operation schedule based on seasonal air temperature differences to optimise natural ventilation. This study demonstrated that occupant thermal comfort can be significantly improved throughout the year with the appropriate use of passive heating and cooling strategies, thereby reducing energy consumption and the environmental impact of buildings.

Thermal comfort prediction of the existing housing stock in southern Spain through calibrated and validated parameterized simulation models

Due to 2030 and 2050 targets of the latest international standards, energetically retrofitting the existing building sector requires special attention. Prior to the proposal of retrofit strategies, it is necessary to analyse the current energy performance of the stock. Although simulation tools provide accurate results of energy performance at the building level, individual assessments of the large-scale stock lead to extensive data collection and huge computational resources. This paper assesses the current performance of one of the most representative building typologies in social housing stock in southern Spain, the H-typology, predicting results on indoor thermal comfort at the stock level. The physical, constructive and geometrical building characterisation and the selection of a calibrated and validated case study through monitoring are used to generate parameterized energy simulation models, providing statistically representative samples of the stock. Open-access energy simulation tools have been combined with statistical software. Conclusions reported show average annual discomfort hours of around 68%, with higher percentage of annual undercooling discomfort hours, and identify the most influential parameters on indoor thermal comfort as infiltration rate, people density and night-time natural ventilation rate. Moreover, 10 Latin Hypercube Samples per parameterized variable derived in highly representative results for thermally analysing the stock.

Retrofitting Building Envelope Using Phase Change Materials and Aerogel Render for Adaptation to Extreme Heatwave: A Multi-Objective Analysis Considering Heat Stress, Energy, Environment, and Cost

Energy retrofitting the existing building stock is crucial to reduce thermal discomfort, energy consumption, and carbon emissions. However, insulating and enhancing the thermal mass of an existing building wall using traditional methods is a very challenging and expensive task. There is a need to develop a material that can be applied easily in an existing occupied building without much interruption to occupants’ daily life while also having high thermal resistance and heat storage capacity. This study aimed to investigate a potential building wall retrofit strategy combining aerogel render and Phase change materials (PCM) because aerogel render is highly resistive to heat and PCM has high thermal mass. While a number of studies investigated the thermal and energy-saving performances of aerogel render and PCM separately, no study has been done on the thermal and energy-saving performance of the combination of PCM and aerogel render. In this study, the performance of 12 different retrofit strategies, including aerogel and PCM, were evaluated numerically in terms of heat stress, energy savings, peak cooling, emission, and lifecycle cost using a typical single-story Australian house. The results showed that applying aerogel render and PCM on the outer side of the external walls and PCM and insulation in ceilings is the best option considering all performance indicators and ease of application. Compared to the baseline, this strategy reduced severe discomfort hours by 82% in a free-running building. In an air-conditioned building, it also decreased energy use, peak cooling demand, CO2 emission, and operational energy cost by 40%, 65%, 64%, and 35%, respectively. Although the lifecycle cost savings for this strategy were lower than the “insulated ceiling and rendered wall without PCM” case, the former one was considered the best option for its superior energy, emission, and comfort performance. Parametric analysis showed that 0.025 m is the optimum thickness for both PCM and aerogel render, and the 25 °C melting point PCM was optimum to achieve the best results amongst all performance indicators for a typical Australian house in Melbourne climate.

A statistical model of the spatial variability of weather for use in building simulation practice

Traditionally, statistically representative (e.g. TMY) weather data is used as boundary condition in building simulation practice and is deemed homogenous for a defined region, e.g., a city. However, this presumed homogeneity does not exist in most cases because due to the effect of variable urban morphology, local weather may be different in different parts of the region. This paper uses Multiple Tensor on Tensor Regression (MTOT) for creation of meso-scale weather for applications in building simulation practice, which is fast and efficient, provided that enough local weather station data and regional morphology data are available. The derived statistical weather model captures variation in local weather due to change in urban morphology with an ensemble mean of standardized mean square error 0.038, i.e, 96.2% of the variation in weather may be predicted by this method. Chicago is used as a demonstration region with a case study of single family dwelling to exemplify the impact of local weather on building performance indicators. A standard deviation of approximately 372 kWh for end use heating, 33.6 kWh for end use cooling and 4 h for hours of discomfort in winters is observed, highlighting the variation caused by the use of local weather in building performance simulation.

Passive heating in thermally compliant office building: Validated and simulated scenarios

This work aims at answering the question–to what extent thermally compliant buildings are involved in ensuring the winter indoor thermal comfort of occupants in cold semi-arid climates in Morocco. Real-time monitoring of a new-built university building located in eastern Morocco was conducted. The good agreement between the measured and simulated temperatures of the case study building confirmed the accuracy of the developed model. Thereafter, the thermal performance of different external wall configurations was investigated. The results show that compliant buildings guarantee better comfort conditions in winter by passively increasing the indoor air temperature by up to 2 °C, resulting in a maximum percentage of dissatisfaction of less than 13%. The winter discomfort hours based on a temperature set point of 16 °C are reduced by 95% compared to typical buildings. Moreover, the thermal compliance of buildings significantly reduces the daily air temperature amplitude, leading to a periodic dynamic behaviour without peak loads, which could be effective for the building energy management. The efficacy of earthen walls in regulating indoor temperatures was also confirmed due to the excellent thermal inertia of earth. For optimum winter comfort (20 °C), the implementation of the Moroccan building energy code shows up to 72% of reduction in heating demand when applied to conventional buildings.

Review of White Roofing Materials and Emerging Economies with Focus on Energy Performance Cost-Benefit, Maintenance, and Consumer Indifference

This article performed a comprehensive review of the different state-of-the-art of roofing technologies and roofing materials and their impact on the urban heat island (UHI) and energy consumption of buildings. The building roofs are the main sources of undesirable heat for buildings, especially in warm climates. This paper discusses the use and application of white roofing material in emerging economies. The use of white roofing material is a suggestion because of its cooling, evaporative and efficiency characteristics compared to traditional black roofing materials. Many research studies have shown that the darker roofing surfaces that are prevalent in many urban areas actually can increase temperature by 1 to 3 degrees Celsius to the environment surrounding these urban areas. Additionally, improved temperature control and heat reflection also work to reduce the energy requirements for the interior spaces of the structures that have white roofing surfaces. The white or lighter colored roofs tend to reflect a part of the solar radiation that strikes the roof’s surface. Consequently, one might believe that white roofing material would be commonplace and especially so within emerging economies. Yet, this is hardly the case at all. This paper examines the issue of white roofing materials in emerging economies from a dual perspective. The dual perspective includes the technical details of white roofing material and its impact on lowering the interior temperature of the affected structures, which consequently reduces hours of indoor thermal discomfort and use of air conditioners in indoor spaces. The other element in this study, however, involves the marketing aspect of white roofing material. This includes its adoption, acceptance and cost-benefit in emerging economies.

Multi-objective genetic algorithm optimization model for energy efficiency of residential building envelope under different climatic conditions in Egypt

The energy sector is always facing huge challenges specially in countries with highly inflated population where the building sector has more pressure to reduce energy consumption. To achieve more energy efficiency in residential buildings with lower life cycle cost (LCC) and enhanced thermal comfort conditions, this study develops a multi-objective genetic algorithm model for the three major climates in Egypt (Mediterranean, semi-arid and arid). The design variables considered include external wall type, roof type, window to wall ratio (WWR), building orientation, HVAC system setpoint and HVAC operation schedule. Available sustainable materials in Egypt are considered for building envelope alternatives, such as limestone and polyurethane expanded. The main findings from the study approved that the optimum solutions in all climates have successfully balanced the reduction in energy consumption and LCC. However, the discomfort hours in both Mediterranean and Semi-arid climates have less reduction percentages compared to the arid climate.

Multi-objective optimization of energy performance for a detached residential building with a sunspace using the NSGA-II genetic algorithm

This paper discusses a performed optimization of the structural and architectural parameters of a detached passive building with a sunspace using a non-dominant sorting genetic algorithm (NSGA-II). The building optimization is performed on the model of a building located in Niš, Serbia, a city with a Cfa climate according to the Köppen classification. The optimization is based on the NSGA-II algorithm and was run using DesignBuilder software package coupled to EnergyPlus™ dynamic building energy simulation software. The defined variable optimization parameters (X1-X10) include parameters of passive solar design, such as window-to-wall ratio (WWR) of each individual building façade, type of glazing, different façade wall constructions, and window shading system on the façades. Prior to the optimization itself, a sensitivity analysis of parameters X1-X10 was conducted in order to identify the parameter that has the most influence on heating and cooling energy expenditure and on thermal comfort. The Latin hypercube sampling (LHS) method is used to create iterations. Optimization objectives are defined for two scenarios. Scenario 1 considers the minimum energy required for heating and the minimum energy required for cooling of a detached passive residential building with a sunspace, while Scenario 2 considers the minimum energy required for heating and the minimum number of discomfort hours in such a building. The results of the optimization are obtained through NSGA-II iterations according to the predefined optimization objectives and by varying the given structural and architectural parameters of the building. The results are presented as a Pareto front – a set of optimal solutions and optimal characteristics of the detached passive solar building. For Scenario 1, the optimization yielded 63 Pareto solutions after 4245 iterations. For Scenario 2, it yielded 25 Pareto solutions after 4393 iterations. Based on the hypervolume indicator (HV), it can be concluded that multi-objective optimization using NSGA-II for Scenario 1 (HV1 = 0.82164) performed better than for Scenario 2 (HV2 = 0.59855). Optimization results show that when designing a detached passive solar building with a sunspace for the Cfa climatic area according to Köppen, window-to-wall ratio is the element of passive solar design that influences energy performance the most. In addition, a detached passive solar building will benefit the most from triple low-emissivity argon-filled glazing, opaque elements of the building envelope need to be properly thermally insulated with thicker concrete or brick walls for higher thermal storage capacity, and no shading or the smallest possible awning size is recommended for the south-facing façade to achieve better solar gains.

SUSTAINABLE DESIGN OPTIMIZATION TOOL FOR PROTOTYPICAL BUILDINGS IN HOT ARID CLIMATE USING ANALYTICAL HIERARCHY PROCESS

New Building Information Modelling (BIM) – enabled performance metrics are gaining importance in Building Performance Simulation (BPS). However, scarce work was published featuring holistic metricsfor prototypical designs in hot arid climate. Thus, this research presents a BIM-enabled sustainable early-design decision support tool, whose optimizationvariables are building orientation and Window-to-Wall Ratio (WWR). The mode’s objective is reaching optimum building Sustainability Combined Score (SCS); the holistic value of performance parameters considered by the user. To demonstrate the methodology, the daylighting and thermal comfort metrics areconsidered: (1) Day-Lit Area (DLA); (2) Daylight Autonomy (DA); (3) Mean Daylight Factor (µDF); (4) Useful Daylight Index (UDI); (5) Temperature Discomfort Hours (TDH); and (6) Humidity Discomfort Hours (HDH).BIM simulation is carried out for various combinations of building orientations and WWR, metrics are converted into percentages then into criteria scores based upon expert-determined criteria rating scales. Next, using the Analytical Hierarchy Process (AHP), Criteria Relative Weights (CRW’s) are determined, using a Pairwise Comparison Matrix (PCM). SCS’s are computed for each scenario, as a function of criteria scores and CRW’s. The verification of the AHP Module is done arithmetically using consistency indices. After screening all valid scenarios considering site constraints, accessibility and design codes, the scenario with optimum SCS is obtained. Three cases of prototypical designs, comprising a school building, a civil defense facility and a congregational building are presented. All cases are located in the hot desert climate ofQatar. The validation of the SCS Module output is carried out using expert survey. اکتسب قياس معدلات أداء المنشآت باستخدام نمذجة معلومات البناء زخما کبيرا في کل من التصميم المعماري المستدام ومحاکاة البناء، وبالرغم من ذلک، قلما نشر من أبحاث تتناول معدلات مجمعة لقياس أداء المنشآت، ولاسيما فيما يتعلق بالتصميمات النمطية في المناطق ذات المناخ الصحراوي الجاف، ومن هذا المنطلق، يقدم هذا البحث أداة مبتکرة لدعم اتخاذ القرار ,والوصول لأفضل المعدلات أثناء مرحلة التصميم المبدئي، حيث تتماشى تلک الأداة المقترحة مع نظم نمذجة معلومات البناء، کما تعتمد تلک الأطروحة على تحليلالحالات الممکنة للمتغيرين:زاوية توجيه المنشأ ونسبة النوافذ إلى الحوائط، بهدف التوصل إلى أفضل قيمة للدرجة الکلية للاستدامة، والتي تمثل قيمة موحدة لکافة مؤشرات الأداء المختارة من قبل المستخدم. وبغرض عرض تلک الأطروحة، تم الاعتماد على هذه المجموعة من مؤشرات أداء الإضاءة الطبيعية والراحة الحرارية: (1) المساحة المضاءة طبيعيا، (2) متوسط معامل الإضاءة الطبيعية ، (3) استقلالية الإضاءة الطبيعية، (4) مؤشر الإضاءة الطبيعية، (5) ساعات درجة الحرارة السنوية غير المستوفاة، (6) ساعات الرطوبة النسبية غير المستوفاة. يتم إذا القيام بالمحاکاة المعتمدة على نمذجة معلومات البناء لکل من السيناريوهات الممکنة لزاوية توجيه المبنى مع نسبة النوافذ إلى الحوائط، ويتم تحويل مخرجات تلک الخطوة، وهي القياسات المنفصلة، إلى نسب مئوية، يتم تحويلها بدروها إلى درجات قياسية استنادا إلى مقياس تم تحديده بواسطة ورشة عمل ضمت مجموعة من الخبراء، وهکذا فإنه باستخدام طريقة التحليل الهرمي يتم التوصل إلى الأوزان النسبية لمعدلات الأداء المختارة، وذلک بتطبيق مصفوفة المقارنة الثنائية على تلک المعدلات، وبناء على ذلک يتم تقدير القيم الخاصة بالدرجة الکلية للاستدامة، والتي تعتمد بالأساس على الدرجات القياسية والأوزان النسبيةلمعدلات الأداء، کما يتم التحقق من منظومة التحليل الهرمي رياضيا باستخدام مؤشرات الاتساق، وبالإضافة إلى ذلک، فبعد إتمام عملية التدقيق لکل سيناريو مقترح - من حيث زاوية التوجيه ونسبة النوافذ إلى الحوائط- في ضوءطبيعة الموقع وأکواد البناء المحلية وغيرها من خصائص المشروع، وقد تم تناول ثلاثة مشروعات ذات تصميمات نمطية، تشمل مبنى تعليميا ومنشأة للدفاع المدني ودارا للعبادة، کأمثلة لتطبيق الأداة المقترحة، تقع کلها في المنطقة المناخية الصحراوية الحارة بدولةقطر، مع عرض النتائج التي تم التوصل إليها، وقد تم التحقق من المنظومة الخاصة بدرجة الاستدامة الکلية بواسطة استقصاء موجه إلى نخبة من المعماريين المتخصصين في مجال الاستدامة ونمذجة معلومات البناء، وتم التوصل بالأخير إلى أن المنشآت ذات المساحات الکبيرة عکست دقة أکثر في عملية محاکاة مؤشرات الاستدامة، وأظهرت قدرا أکبر من التأثر بالتغيير في القيم المدخلة من زاوية توجيه المنشأ أو نسبة النوافذ إلى الحوائط، مقارنة بالمنشآت الأصغر مساحة التي لم تتأثر نتائجهابنفس عند تغيير قيم المتغيرات.

Adaptive Thermal Comfort of Planned Low-income Housing of a Developing Country: Case of Kigali, Rwanda

Global warming is expected to raise the average temperature of the tropical region by up to 3?4°C in the next 70 years. Due to the vulnerable living conditions that are predominant in mostdeveloping countries in the region, this will dramatically affect the indoor thermal performanceof exclusively, naturally ventilated buildings that form the majority of residential buildings inless-industrialized nations. In addition, the lack of knowledge about the built environment andthermal comfort design guidelines may significantly affect locals’ health and well-being,especially among low-income groups. This study evaluates the thermal performance of lowincomehousing that were constructed as a governmentsponsored project for urban revitalizationin Kigali, Rwanda. Dynamic thermal simulations are carried out through EnergyPlus softwareusing the DesignBuilder program as user interface. Annual discomfort hours and discomfortdegree-days are calculated using the ASHRAE 55 adaptive comfort model. The results indicatepoor thermal environmental conditions in this planned low-income housing structure. Indooroperative temperature is outside the adaptive comfort range for about 70% of time annually with955.3 discomfort degree-days. The roof was found to be the key element causing indoortemperature to exceed the upper comfort temperature threshold, while wall material mostlyinfluenced indoor temperature below the lower comfort temperature limit.

Sensitivity analysis on energy performance, thermal and visual discomfort of a prefabricated house in six climate zones in Australia

In prefabricated buildings distinctive construction process and lightweight components affect design strategies and consequences. Therefore, to create more sustainable prefabricated buildings, it is important to understand the effects of their envelope parameters on energy performance and indoor environmental quality. Although previous research have investigated the effects of envelope on energy and indoor comfort outputs, the parameters of lightweight prefabricated envelope are not thoroughly considered. This article quantifies the effects of building envelope parameters on the energy use, thermal comfort and daylighting levels of a prefabricated house built in Australia. A building simulation model was developed and validated by comparing predicted with measured indoor temperatures of the house. The baseline performance for evaluation of energy consumption, thermal discomfort hours and daylight unsatisfied hours were carried out using Transient System Simulation (TRNSYS) tool. Series of regression-based sensitivity analyses (SAs) to identify the most sensitive parameters were conducted by coupling TRNSYS, jEPlus and SimLab. Applications in six climate zones were investigated. The important focus areas found by SA in each climate and their corresponding design responses can be applied across ranges of prefabricated building projects if built in similar climatic conditions. SA results revealed window glazing and shading among the most influential parameters on all targeted performance outputs. The relationship between sensitivity levels to energy consumption and degree days indicated that the type of window has a higher impact on the reduction of energy use in the cooling dominated climates while insulation of wall was found a more effective strategy in heating-dominated climates.

Multi-objective building design optimization considering the effects of long-term climate change

Building performance is heavily influenced by weather conditions. Though the climate is changing vastly, few building performance optimizations (BPO) consider global warming over the life expectancy of the buildings. This paper develops a novel multi-objective BPO framework by the using simulation-based surrogate models under the future weather conditions that are determined by morphing the typical meteorological year (TMY) data. This framework is adopted to optimize a typical classroom in a hot and humid area under the future weather scenarios of representative concentration pathways (RCP) 4.5 and 8.5. The energy, thermal comfort and daylighting performances with and without considering the climate changes in the optimizations are compared and their notable differences are discussed. Under future climate, the optimization considering the future climate change improves the building performances significantly compared to the optimization without any climate change considerations (i.e., using the historical TMY). Especially, the winter discomfort hours in RCP4.5 and 8.5 decrease by 7.4% and 13.3%, respectively, when such future climate changes are considered in the BPOs, compared to the BPOs using the historical TMY data. The results show that BPO without considering climate change effects may cause non-negligible uncertainties. The proposed method can effectively improve the building performance in a changing climate.

Passive Cooling Solutions to Improve Thermal Comfort in Polish Dwellings

The household sector in Poland consumes more than 25% of final energy. At the same time, residents reported dissatisfaction with the thermal conditions during the summer months. This paper details the search for passive and energy-efficient solutions to improve thermal comfort in Polish dwellings. A five-story, multi-family building was selected for this research. Analyses were conducted in apartments located on the top two floors using EnergyPlus (for thermal calculations) and CONTAM (for air exchange calculations) simulation programs for current and future climatic conditions. The stochastic behavior of people when opening windows and automatically controlled systems supplying external air to the building was considered. Airing the apartments by opening windows increased the heating demand but reduced the number of thermal discomfort hours by over 90%. The degree of airing by opening windows depends on residents opening their windows; therefore, a mechanical supply of external air controlled by both internal and external temperatures was proposed and tested.

Climate change and energy performance of European residential building stocks – A comprehensive impact assessment using climate big data from the coordinated regional climate downscaling experiment

In recent years, climate change and the corresponding expected extreme weather conditions have been widely recognized as potential problems. The building industry is taking various actions to achieve sustainable development, implement energy conservation strategies, and provide climate change mitigation. In addition to mitigation, it is crucial to adapt to climate change, and to investigate the possible risks and limitations of mitigation strategies. Although the importance of climate change adaptation is well-understood, there are still challenges in understanding and modeling the impacts of climate change, and the consequent risks and extremes. This work provides a comprehensive study of the impacts of climate change on the energy performances and thermal comfort of European residential building stocks. To perform an unbiased assessment and account for climate uncertainties and extreme events, a large set of future climate data was used for a 90-year period (2010–2099). Climate data for 38 European cities in five different climate zones, downscaled by the “RCA4” regional climate model, were synthesized and applied to simulate the respective energy performances of the residential building stocks in the cities. The results suggest that there will be larger needs for cooling buildings in the future and less heating demand; however, there are differences in the variation rates between zones and cities. Discomfort hours will increase notably in cities within cooling-dominated zones, but will not be affected considerably in cities within heating-dominated zones. In addition to long-term changes, climate-induced extremes can considerably affect future energy demands, especially the cooling demand; this may become challenging for both buildings and energy systems.