Discomfort Hours Research Articles

Retrofit Measures for Achieving NZE Single-Family Houses in a Tropical Climate via Multi-Objective Optimization

To achieve sustainable cities and communities, it is necessary to decarbonize existing buildings. Actions need to be taken to reduce the buildings’ energy demand and ensure that the low remaining demand is met by energy produced from renewable sources. This leads to Net Zero Energy Buildings (NZEBs), whose impact on energy consumption is zero or positive, meaning that they are able to produce more energy than they require. The “zero” objective may be difficult to reach in hot and humid climates, where the cooling demand is prevalent. In this case, a combination of active and passive measures, together with appropriate interaction with users, is a viable way to obtain NZEBs. The present study aims to explore technological solutions for renovating existing buildings to NZEBs in a tropical climate. The analysis is developed through a parametric analysis, a sensitivity analysis, and an optimization directed at minimizing the site’s net energy and hours of discomfort. Evaluations are conducted for a case study consisting of a single-family house located in Panama City. The results showed that photovoltaic size, cooling operation schedule, and cooling set-point temperature are the most influential variables for the attainment of NZEBs in a hot climate. Regarding the building envelope, the outcomes suggest the low insulation of dispersing structures and local solar shading of windows as recommended measures.

Optimizing energy efficiency and thermal comfort of green envelope applications in hot arid climate

Climate change and unresolved environmental challenges in arid environments negatively affect urban development. Previous literature tackled the significance of ecological approaches and building envelope optimization as main pillars in reducing energy consumption and enhancing energy efficiency and thermal comfort in buildings. This study aims to tackle an environmental simulation of implementing green roofs and green walls as an ecological strategy applied to the building envelope with considerations of the window-to-wall ratio (WWR) in contribution to enhancing the built environment’s energy efficiency and thermal comfort. The main study aimed to define the optimum solutions for applying ecological approaches on a medium office building envelope to investigate the enhancement of thermal comfort and total site energy. Hot arid climatic data was selected for its recent environmental challenges, and building envelope design, relying on experimental simulation research, a model was simulated using Design-builder software using discomfort hours and total site energy as the main objectives. Heating and cooling were added as outputs in the optimization to monitor their effect on the indoors. The two main output parameters were the WWR and envelope construction. Then a percentage decrease in the running cost was addressed. The multi-objective optimization showed an effective positive impact of green roof application on the building in hot arid climate than that of the green wall, which highlights the significance of green wall implementation to environmental and economic sustainable developments in arid environments.

Optimization control strategy for mixed-mode buildings based on thermal comfort model: A case study of office buildings

Mixed-mode (MM) buildings reduce air conditioning (AC) energy consumption while maintaining indoor thermal comfort through the appropriate use of natural ventilation (NV). The objective of this investigation was to propose a method to determine the best NV operation range suitable for MM buildings and further to propose a change-over control strategy. First, the usual natural ventilation operating range (NV-range) was obtained based on the upper and lower comfort temperature limits of the adaptive comfort model. The usual NV-range was extended by adding threshold conditions, and then, it was divided into nine natural ventilation operation subranges (NVOSs). Second, the comfort and energy performance of each NVOS were analyzed through a co-simulation for an MM office building in Xi'an, China, as an example to obtain the optimal NV-range for the local climate. The results showed that the proposed optimal NV-range reduced the number of discomfort hours by 248.33 h while increasing the energy savings by 13.29% compared to those of the commonly used NV-ranges. Finally, the control scheme with the adaptive comfort model changed to the PMV model (ACM-PMV-CS) with the addition of a 1.5-h transition period was proposed in order to solve the problem of using the steady-state PMV model directly in the AC mode under the frequent switching conditions between the NV and AC modes. The results showed that ACM-PMV-1.5 h transition period resulted in a reduction in the number of discomfort hours (248.33 h) and a 35.46% increase in the energy savings compared to those of ACM-PMV-CS without a transition period.

Thermally Future-Proofing Existing Libyan Housing Stock with Biobased Insulation Materials and Passive Measures: An Empirical and Numerical Study Using a Digital Twin

Thermal refurbishment and retrofitting building envelopes with passive measures such as the optimisation of opaque and transparent fabric performance may play a key role in reducing cooling and heating load and promoting building energy efficiency. Furthermore, to reduce the embodied carbon impact of the building, the refurbishment measures need to consider the use of low-carbon building materials. This paper investigates ways to thermally future-proof typical Libyan houses using biobased materials. Several typical Libyan houses were monitored for one year to investigate the heating and cooling energy use and to thermally retrofit the building envelope. A digital twin was created in the DesignBuilder software using the real building data of one building for digital model calibration. Finally, multi-objective optimisation was carried out with low-impact biobased materials for insulation, including camel hair, sheep wool, and date palm fibre as well as using other optimisation variables such as shading and glazing types. The study reveals that thermally upgrading the building roof and wall with insulation materials and upgrading the windows with energy-efficient glazing and local shadings can achieve a reduction in cooling load from 53.51 kWh/m2/y to 40.8 kWh/m2/y. Furthermore, the heating load reduces from 19.4 kW/m2/y to 15 kW/m2/y without compromising the standard annual discomfort hours.

Comparison analysis of temperature and thermal energy needs of two earth-based constructions in the hot semi-arid climate

ABSTRACT As climate change is globally widespread and intensifying, there is an urgent call for buildings to undergo energy reduction and decarbonization in order to reach carbon-neutrality by 2050. This article comes in response to this need, by comparing the thermal energy savings and discomfort mitigation from implementing climate-responsive design strategies with respect to the hot semi-arid climate of Morocco. To do so, we’ve used EnergyPlus to evaluate the thermal energy performance and indoor thermal comfort conditions of two passive unoccupied homes: Home_1 and home_2; and the accuracy of the building energy models has been approved via forty days of indoor temperature measurements in two different thermal zones for each home. Furthermore, the comparison of the annual thermal needs of both passive homes has demonstrated that passive design strategies influence heavily the thermal performance of the buildings and help mitigate indoor comfort conditions, especially in the cooling period. A combination of semi-arid climate-responsive passive design strategies for home_2 has allowed to reach a thermal energy intensity of 23.31 kWh/m2/year, which is less by 73.3% in comparison with the thermal energy needs of home_1 and also Discomfort Hours (DH) in home_2 is 2069 h, against 5744 h in home_1.

Evaluation of the Effectiveness of Passive Design Strategies in Achieving Thermal Comfort in Residential Buildings in Egypt

This study aims at thermal comfort improvement in residential buildings through utilization of passive design strategies and energy efficiency measures. The study investigates the impact of passive strategies on thermal comfort in hot dry climate of Egypt. A climatic analysis of three cities: Aswan, Cairo and Alexandria was conducted to examine passive design strategies’ efficacy. Thermal comfort in a residential building was examined by DesignBuilder simulation software. Annual simulations were performed on the model where several passive design strategies were applied. Passive design strategies’ potential was quantified and a parametric analysis was conducted for thermal comfort improvement. The results demonstrate that applying passive design strategies can be effective in reducing discomfort hours in hot climate. Comfort hours could be increased from 22.6% to 33.1 % in Aswan, while in Cairo can be increased from 31.1% to 38.6 %, and in Alexandria from 36.9% to 46 %. The research findings could be used by architects for thermal comfort improvement in residential buildings.

Predicting climate change and occupants’ behaviour impact on thermal-energy performance of global south housing: Case study in Brazil

Due to climate change conditions, natural ventilation potential may reduce over the years and increase dependence on HVAC systems. Moreover, occupants’ behaviour regarding natural ventilation is a significant parameter affecting the thermal-energy performance of residential buildings as people tend to occupy their homes differently depending on their life, work and cultural routines. Therefore, in this study, the thermal-energy performance of a Global South (GS) housing case study located in Brazil was assessed in a future weather context. This paper included two major steps: (1) Optimization procedure to create optimized models based on different occupancy patterns; and (2) Parametric analysis to explore the building’s thermal-energy performance for a given constructive design option, occupant behaviour and weather data. The optimization procedure included a multi-objective optimization based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II) to minimize discomfort hours and cooling energy demand, while parametric analysis explored the occupants’ behaviour varieties derived from alternative occupancy patterns, ventilation availabilities and HVAC operation modes. The obtained future context simulation results indicated an increase in discomfort hours and cooling energy demand, while the most appropriate architecture design might vary depending on the occupancy behaviour.

Building Optimisation Vis-À-Vis Solar Shading for Improved Comfort and Energy Efficiency in Classrooms

Excessive solar radiation negatively affects classroom occupants' perfor­mance and thermal comfort, especially in buildings with West and East-facing glazed openings. This study utilises fixed external shading devices and triple-glazed low-emissivity windows to optimise a classroom building in Nigeria. Employing hybrid ventilation mode in EnergyPlus simulations, the optimised model shows a 44% reduction in discomfort hours, a 23% decrease in cooling load, and a 16% drop in energy demand compared to the original design. Comparative analysis of the optimised model with the as-built and West-East oriented classroom reveals a 16% and 10% reduction in energy consumption per conditioned area, along with 56 KWh/m² and 32 KWh/m² savings in cooling demand, respectively. Despite the effectiveness of fixed shading in curbing solar gains, occasional glare persists. This research underscores that shading alone may not fully meet thermal comfort requirements, emphasising the importance of building fabrics, building orientation and climate-sensitive design.

Evaluation of the thermal performance of housing envelopes as passive cooling systems

Over the years, climate change has generated an increase in the average temperature of the planet, which has led to greater consumption of electrical energy for the use of air conditioning systems. Insulating envelope materials are considered a viable passive solution as they offer internal air conditioning, cooling, and/or heating of buildings that lead to thermal comfort with reduced energy consumption. This article compares the application of different insulating materials in an existing single-family home located in a hot-dry climate. To this end, the procedural methodology has been applied by carrying out a bibliographic review of different involutes currently used in the construction of the buildings and 14 models are proposed that will be simulated under the same input variables of the base model and meteorological data of the city of Bucaramanga validated from a meteorological station located on site. The results of the simulations show that all 14 models show a decrease in temperature with reference to the "base model"; This difference can be explained by the presence of the selected materials that slightly change the thermal properties of the wall. Finally, this research allowed us to determine that the occupants of the simulated spaces in the base model are inside the thermal comfort range by 61.96%, which represents 5,438 hours of the modeled year, having 38.03% of hours of discomfort in the measured time. This study can be useful for the selection of envelopes and different buildings with passive cooling requirements.

Evaluating Thermal Performance and Environmental Impact of Compressed Earth Blocks with Cocos and Canarium Aggregates: A Study in Douala, Cameroon

A novel low-cost earthen construction system integrating biosourced aggregates is proposed for houses’ erection of low-income households. This study is based on in-situ measurements on two representative test cells constructed in Douala, with a typical hot and humid climate. One of these buildings is made with a hollow cement block as a reference, and the other with biosourced earth bricks modified with Cocos nucifera and Canarium schweinfurthii aggregates. Dynamic thermal simulations of the two test cells were performed using the EnergyPlus building performance simulation program. The results are based on measuring air temperature and humidity, and the simulation leads to defining the discomfort hours and the annual energy consumption. The adaptive ASHRAE 55 thermal comfort model was used to evaluate the comfort conditions. The results show that air conditioning systems provide the best comfort systems with minimums of about 95% for plastered and unplastered wall construction systems. Biosourced compressed earth brick constructions offered the best thermal performance with comfort ranges of around 96% and 44% for air conditioning and natural ventilation, respectively. In terms of energy consumed, there was a gain of about 100 kWh over the year. Energy consumption is lower in the biosourced compressed earth brick building than in the hollowed cement block building: this one offered the lowest comfort range of about 40% in natural ventilation. The construction provisions were considered for the life cycle assessment, and two scenarios describing the origin of the cement raw materials were considered. It can be seen that cement accounts for more than 95% of the impacts for both construction systems, as well as for the scenarios of its origin. In all situations, the hollowed cement block construction presented the highest impact on the global warming potential: 66 KgCO2eq and 89 KgCO2eq, respectively, without plaster and with plaster. It can also be seen that the plastered layer had a carbon footprint (in terms of Green House Gas Emissions (GHG emissions)) of almost 40% on the overall functional unit. Canarium Schweinfurthii and Cocos Nucifera materials accounted for only 1% of the overall impact.

Natural ventilation effectiveness in low-income housing to challenge energy poverty

The steady rise in global average temperatures due to climate change is leading to a significant increase in cooling energy demand worldwide. Despite having the least access to energy, the Global South will experience the greatest increase in cooling degree days (CDD), forcing the majority of the world’s population to endure highly uncomfortable temperatures in the buildings. As a result, it becomes crucial to prioritize passive design-based approaches to air conditioning, to mitigate the increasing demand for active cooling while ensuring equitable space cooling opportunities for all. This work, combing the CFD simulation with building energy modeling, evaluates the impact of natural cross-ventilation and building form on improving indoor thermal conditions in hot and arid climates. The analysis, focusing on low-income housing prototypes designed by Indian architect Charles Correa, demonstrates how proper building form design, by improving the ventilation and cooling efficiency of buildings, can ensure indoor thermal comfort even in challenging climatic conditions, helping to reduce energy consumption and prevent energy poverty. Natural ventilation provides an operative temperature reduction of up to 3.1 °C on the hottest day and up to 3.9 °C on the typical cooling period day. Even discomfort hours are drastically reduced by 31.3 % and 77.8 % respectively.

Surrogate model of adaptive thermal comfort of a social housing in the Dominican Republic micro-climates: a predictive approach toward sustainable buildings

ABSTRACTAdaptive thermal comfort is essential for guaranteeing the well-being of building occupants. Therefore, this study emphasizes its importance and applies advanced computational techniques as a surrogate model and sensitivity analysis for an in-depth analysis of a social housing in the Dominican Republic evaluated under five micro-climates. The methodology includes a computational design with an energetic simulation. An adaptive model was developed following the ASHRAE-55 standard, and an artificial neural network was trained to predict comfort temperature. The results showed that Neiba city, corresponding to a hot semi-arid climate, presented the maximum hours of discomfort (8463), representing 96.6% of the total annual hours with a cooling degree day of 157.5, whereas Constanza city, corresponding to the oceanic climate, reported 2025 hours of discomfort (23.1%) and a cooling degree day of 48. The surrogate model based on artificial neural networks achieved a coefficient of determination of 0.9998, and the sensitivity analysis revealed a more significant influence of radiant temperature (55.96%) over comfort temperature. Finally, this study highlights the significance of adaptive thermal comfort in building design and the potential of surrogate models for energy analysis. Therefore, it is necessary to implement passive strategies to enhance indoor thermal comfort in a sustainable building sector.

Influence of cross-ventilation cooling potential on thermal comfort in high-rise buildings in a hot and humid climate

The rising cooling energy demand, caused by the increase in global average temperature and the frequency of heat waves, is currently leading to a significant increase in global electricity consumption. Passive cooling strategies, such as ventilative cooling, can provide acceptable indoor thermal comfort with no or minimal energy consumption, offering an alternative to air conditioning systems in buildings. This paper investigates the effectiveness of natural ventilation in an iconic post-modernist high-rise building in India: Charles Correa's Kanchanjunga Apartments. The research, employing CFD simulation paired with building energy simulation, demonstrates how cross-ventilation can improve the ventilative cooling efficiency in buildings, ensuring affordable indoor thermal conditions even in adverse climatic conditions like the Indian one. Thanks to night-time structural cooling, a maximum reduction in the operative temperature of up to 5.3 °C was achieved compared to the scenario without natural ventilation and up to 6.4 °C compared to the outdoor temperature peak on the hottest day. Consistently with the Indian Model for Adaptive Comfort, cross-ventilation ensures a reduction in discomfort hours of up to 58 % on the hottest day and a total reduction in discomfort hours on a typical monsoon and winter day. The paper aims to assist architects and policymakers in quantifying the cooling potential of natural ventilation in high-rise buildings, suggesting passive solutions for cooling energy saving.

Improving building resilience in the face of future climate uncertainty: A comprehensive framework for enhancing building life cycle performance

This research introduces an innovative resilient design framework, addressing gaps in building performance optimization by considering a holistic life cycle perspective and factoring in climate projection uncertainties from the 2020s to 2090s. The study concludes that in the case study, future climate scenarios in different Shared Socio-Economic Paths significantly impact building life cycle performance, with wall U-value, windows U-value, and wall density identified as major factors affecting building performance under future climate uncertainty. The ensemble learning model achieves high fidelity in predicting life cycle carbon emissions (LCCE), life cycle cost (LCC), and indoor discomfort hours (IDH) through input feature screening and hyperparameter optimization. Comparing optimization algorithms, Two-Archive Evolutionary Algorithm for Constrained multi-objective optimization (C-TAEA) demonstrates better convergence degree and optimization effect. Among the tested multi-criteria decision making methods, the VIKOR method selects the best building resilient design scheme from the Pareto data set, effectively reducing LCCE, LCC, and IDH, and leading to an overall improvement in building life cycle performance. Applying this framework, the finalized scheme for an office building in cold region optimizes 44.0% of LCCE, 8.2% of LCC, and 4.3% of IDH. This framework develops a new approach to improve building life cycle performance under future climate uncertainty and supports informed decision-making for resilient building design. To promote carbon neutrality in construction, it is urged that future studies incorporate additional sources of uncertainty, such as occupant behavior, into the proposed framework.

Exploring adaptive strategies to cope with climate change: The case study of Le Corbusier's Modern Architecture retrofitting

Historic buildings, often exempt from retrofits to preserve originality, require retrofitting due to potential future climate-related indoor issues. For Modern Architecture constructions, there is a need to find solutions that help address the discomfort and heat losses caused by the extensive use of glazing. By analysing Le Corbusier's studio-apartment this paper aims to inspect: (i) Solutions for energy, Indoor Environmental Quality, and preservation; (ii) Climate change impact on them; (iii) Possible adaptation strategies to cope with climate change. Spectrally selective glazing reduced summer overheating by 15%; high-performance glazing lowers cold discomfort (24%) and heating (22%) but increased warm discomfort; shadings maintained energy use and reduced summer discomfort by up to 44%; thermal insulation can reduce winter discomfort and halves energy use but raised summer discomfort by up to 41%. Tests on 2050–2100 climate change scenarios reveal up to 70% more warm discomfort hours. Adaptive strategies can help, with natural ventilation cutting warm discomfort by 50–60%, and adaptive setpoints reducing cooling demand by about 35%. Adaptive strategies can complement traditional retrofitting in addressing current and future climate conditions, especially in historic buildings that require minimal interventions to preserve their historical characteristics and enhance resilience.

Identification of influential factors for combined energy consumption and indoor environmental quality in residential buildings

The development of an overall building performance simulation model requires a multitude of input parameters which can be a challenging and resource-heavy task for building modellers. Furthermore, some parameters have little impact on a building’s overall performance and contribute little towards model prediction accuracy. Feature selection has been employed to identify the most influential input parameters to reduce complexity and computational time. However, previous studies focused mainly on identifying parameters that impact energy consumption in residential buildings, neglecting the important relationship between energy consumption and indoor environmental quality (IEQ). Therefore, this study proposes a novel simulation framework that integrates occupancy-based building archetypes, parametric simulation, and machine learning techniques to develop an overall building performance prediction model. Using this framework, the study generates a synthetic dataset of 40,000 simulations and performed embedded feature selection using two machine learning algorithms, Random Forest (RF) and Gradient Boosting Technique (GBT), to identify parameters that impact heating energy consumption, thermal discomfort hours, and CO2 concentration simultaneously. The results demonstrate that the ranking for importance and the number of required parameters vary depending on the target variable. Also, the set of parameters for combined analysis differs from individual target variable analysis. The GBT algorithm with embedded feature selection provides the most accurate prediction results with lower root mean square error (RMSE) and absolute error (AE) for individual and combined analyses. This study provides valuable insights for accurate parameter selection and analysis of overall building performance.

Influence of Occupants’ Space and Appliance Use Patterns and Behaviour during the Discomfort on Electricity Consumption in Mixed Mode Residences

Building characteristics, climate, socio-economic characteristics, and occupant behaviour influence the electricity consumption in buildings. In residential buildings, where people spend a lot of time and have high perceived control over their surroundings, electricity consumption for thermal comfort constitutes a higher proportion of overall energy consumption. Previous research studies mainly focused on the impact of building and household characteristics on electricity consumption in residences. In the Indian context, electricity usage in residential buildings may depend on lifestyle, family composition, daily routines and activity patterns, and consumption habits. In India, the space usage and sharing pattern of internal spaces depend on family composition and the number of rooms. In India, the usage of household appliances has been steadily increasing. During discomfort hours in humid conditions, people use fans with windows in the open position, switch on the air-conditioner or use the fan and air-conditioner together to attain thermal comfort. Therefore, the study aims to assess the impact of family composition, occupants' space and appliance use patterns and behaviour during the thermal discomfort on electricity consumption in Indian residential buildings. Information on the number of occupants, children, and elders; space usage at different hours of the day by the occupants; use of fans, air-conditioners, and other electrical appliances; and frequency and hours of opening of windows were collected through a questionnaire survey from 144 residences. Electricity consumption data for all 144 residences were collected from the utility bills. The variables influencing annual mean electricity consumption per unit area of residential buildings include the number of elders present, age of children, hours of air-conditioner use, space usage pattern, and occupants' behaviour during the discomfort

Building for a sustainable future: investigating the thermal performance of innovative and local wall materials in an Egyptian housing unit

ABSTRACT Nowadays, the majority of nations are facing the challenge of global warming which has caused less thermal comfort in indoor environments with further energy consumption. To mitigate these negative impacts, selecting appropriate building materials with environmental design principles is crucial to meet user’s needs. This study aims to investigate the impact of implementing innovative and locally sourced building materials in the wall construction of a residential building in Egypt; to improve energy consumption and users’ thermal comfort. The thermal performance of six alternative walls was analyzed and compared using computer simulation software. Alternative wall systems included innovative materials, such as Marmox boards and aerogel panels, as well as local materials such as double wall, Singer clay blocks, and Mudbrick with strawbale. The simulation results demonstrated that the Mudbrick strawbale exhibited the best thermal performance among all alternatives. It reduced energy consumption by 45% and decreased discomfort hours to an average of 18 hours per year. The innovative materials, Marmox board, and Aerogel panel, also showed promising results that were comparable to those of Mudbrick strawbale. This confirms that local materials can offer superior thermal performance when used in appropriate wall techniques. The overall study results revealed that implementing alternative wall strategies using environmentally sustainable building materials in residential settings can lead to energy savings ranging from 29% to 45%, as well as a reduction in annual discomfort hours by over 50%. This study highlights the effectiveness of using alternative wall strategies as a solution for addressing environmental adaptation gaps in residential settings.

Optimal configuration of architectural building design parameters for higher educational buildings

In architectural building design, finding an equilibrium between energy consumption and thermal comfort poses a challenge due to their inherent conflict. To effectively incorporate both aspects, their integration into the decision-making process is crucial. This study demonstrates the optimization of architectural building design parameters for a single-story educational building within a warm temperate climate in New South Wales, Australia. A meticulous validation process was undertaken using the Monte Carlo approach and scrutinizing 2,000 distinct scenarios for each parameter. This validation compared simulation outcomes with field-measured data, confirming the model’s prediction accuracy. The optimization endeavour employed the non-dominated sorting genetic algorithm to facilitate multiobjective optimization , working with the Pareto front solution. When compared with the baseline building simulation model, the optimized architectural design parameter configuration yields significant reductions of up to 24% in total EC and up to 16.5% in thermal discomfort hours.

Low-energy resilient cooling through geothermal heat dissipation and latent heat storage

Conventional passive cooling techniques provide limited benefits in extremely hot climates in southern Asia, characterised by high daytime and night temperatures and frequent climate-related disruptions, such as power cuts. This study proposes and demonstrates a novel low-energy and resilient cooling solution for extremely hot regions in southern Asia. The novelty lies in the combination of geothermal heat dissipation and latent heat storage, specifically designed for the particular conditions of extremely hot climates in Southern Asia; considering the influence of climate-related disruptions such as power cuts, whose frequency is increasing in the region; and using discomfort hours as an indicator to measure the passive survivability of buildings in the absence of air-conditioning (following the adaptive comfort model). A numerical model was developed in TRNSYS for optimal sizing and configuration of the phase change material (PCM) integrated into a ceiling panel using a typical multi-family building archetype in three climatic regions of Pakistan. A parametric numerical analysis was performed concerning different PCM melting temperatures, amount of PCM, convective heat transfer capacity, and equivalent thermal conductivity. Moreover, daytime was considered the period with a higher probability of power cuts. The results showed how integrating PCM-based ceiling panels with geothermal heat dissipation can mitigate discomfort hours by 28 % in extremely hot climates, 55 % in very hot climates, and 91 % in hot climate areas with intermittent access to electricity. Latent heat storage maximised the benefits of geothermal heat dissipation by extending thermal comfort periods by 13 % and 18 % in extremely hot and very hot climates compared to the scenario without PCM. This low-energy resilient cooling solution, integrating PCM as a cool battery, can keep the home cool for longer when electricity is unavailable. This study demonstrates the importance of considering the specific climate-related disruptions from these extremely hot regions in building design, such as extreme heat events or power cuts, to enhance the heat resilience capacity of cities.