Improvement Of Thermal Comfort Research Articles

Informing building retrofits at low computational costs: a multi-objective optimisation using machine learning surrogates of building performance simulation models

Machine learning (ML) algorithms are increasingly used as surrogates for building performance simulation (BPS) models to leverage their energy predictive capabilities while reducing computational costs. In parallel, researchers are developing optimisation methods to inform building design and retrofit strategies but rarely employ ML-based BPS surrogates for this purpose. This study proposes a coupled modelling approach that leverages the capabilities of ML-based BPS surrogate models and multi-objective optimisation to inform holistic design and operation retrofits at low computational costs. The proposed methodology is demonstrated using an archetypal office building in Ottawa, Canada. The developed models achieved competitive predictive accuracies (adjusted R2: 0.90–0.99), identifying total and peak energy saving measures with up to 34% improvement in occupant thermal comfort at computational speeds 1266 times faster than a traditional BPS-based optimisation approach. Results offer a promising modelling workflow for design applications requiring extensive computations and scenario analyses, such as net-zero energy retrofits.

Experimental study on improving effect of cooling garment on thermal comfort and EEGs

Phase change cooling garments (PCCGs) utilize phase change materials to store and release thermal energy, which can be used to reduce thermal sensation in hot environments. This study aims to investigate the effects of PCCGs on thermal comfort and electroencephalography (EEG) signals for laborers in hot conditions. Experiments were conducted in a climate chamber at 33 °C with 50 % relative humidity, with subjects having a metabolic rate of 2.7 met. EEG signals from 20 participants were recorded using a 32-channel EEG system after completing laboring task wearing the PCCGs or normal garment (NG), and the mean power of EEG and topological features of the brain network were analyzed. The results indicate that the use of PCCGs significantly reduce the mean power of the EEG signals, with notable changes in the θ, α, and β-bands. Additionally, wearing PCCGs alters the topological structure of the brain network, and the inter-regional information exchange was enhanced, as evidenced by the increased clustering coefficient, global efficiency, local efficiency, and decreased characteristic path length of the brain network. In this study, the effects of PCCGs on thermal comfort, EEG activity and brain network of laborers in hot environment were explored, which provides a possible indicator for assessing the improvement of thermal comfort by PCCGs.

Enhancing Thermal and Daylight Performance of Historic Buildings with Passive Modifications; A Tropical Case Study

Historical buildings worldwide hold immense potential for adaptive reuse within the framework of the circular economy, a concept gaining traction in the building construction industry for its role in reducing carbon emissions. Many of these structures boast passive building design strategies, which inherently lower energy demands. Among these, thermal mass and daylight harvesting emerge as pivotal strategies for achieving indoor thermal and visual comfort, respectively. However, with the advent of significant climate change and evolving built environments, the efficacy of these historical passive strategies is subject to debate. This study focuses on a residential building constructed in the 17th century by Dutch settlers in Galle, Sri Lanka, serving as a case study. The research targets improvements in both thermal and visual comfort. Thermal performance analysis was conducted through air temperature measurements, revealing a notable 3-hour time lag and a 2.5°C reduction in peak air temperature during the day. Conversely, nighttime measurements indicated a rise in indoor temperature compared to ambient conditions. Using Design Builder software, the building was modelled to assess its daylighting conditions. Drawing upon thermodynamic principles and daylight harvesting techniques, the study proposes building envelope interventions and ventilation strategies to address nighttime overheating and enhance daylight utilization. The results demonstrate that these modifications can potentially reduce nighttime heat by 2-3°C, while also decreasing the energy requirement for lighting comfort from 51.10 kWh/m² per annum to 44.84 kWh/m² per annum. This research showcases the effectiveness of judiciously implemented interventions in historical buildings, illustrating tangible improvements in both thermal/visual performance and energy efficiency. Leveraging inherent qualities of historical structures and integrating modern design strategies to these buildings can play a vital role in sustainable urban development and energy conservation efforts.

Vests with Radiative Cooling Materials to Improve Thermal Comfort of Outdoor Workers: An Experimental Study.

This study focuses on improving human thermal comfort in a high-temperature outdoor environment using vests with a radiative cooling coating. The effects of coating thickness on the radiative cooling performance were first evaluated, and an optimal thickness of 160 μm was achieved. Then, six subjects were recruited to evaluate the thermal comfort in two scenarios: wearing the vest with radiative cooling coatings, and wearing the standard vest. Compared with the standard vest, the coated vest decreases the maximum temperature at the vest inner surface and the outer surface by 5.54 °C and 4.37 °C, respectively. The results show that thermal comfort is improved by wearing radiative cooling vests. With an increase of wet bulb globe temperature (WBGT), the improving effects tend to decline. A significant improvement in human thermal comfort is observed at a WBGT of 26 °C. Specifically, the percentage of thermal sensation vote (TSV) wearing the cooling vest in the range of 0 to 1 increases from 29.2% to 66.7% compared with that of the untreated vest. At the same time, the average value of thermal comfort vote (TCV) increases from -0.5 to 0.2.

Expert-guided imitation learning for energy management: Evaluating GAIL’s performance in building control applications

The use of Deep Reinforcement Learning (DRL) in building energy management is often hampered by data efficiency and computational challenges. The long training time, unstable, and potentially harmful control performance limit DRL’s adaptability and practicality in building control applications. To address these issues, this study introduces a new method, called Generative Adversarial Imitation Learning (GAIL), which effectively utilizes expert knowledge and demonstrations. Expert demonstrations range from fine-tuned rule-based controls to strategies inspired by optimization algorithms. By combining the capabilities of the generative adversarial network and imitation learning, GAIL is known for effectively learning the optimal strategy from expert demonstrations through an adversarial training process. We conducted a comprehensive evaluation comparing GAIL’s performance with the DRL algorithm Proximal Policy Optimization (PPO) in the scenario of controlling a variable air volume system for load shifting in commercial buildings. Impressively, GAIL, guided by expert demonstrations based on model predictive control, achieved significantly improved computational efficiency and effectiveness. In terms of unified cumulative reward, GAIL with data augmentation achieved 95% expert performance, 22% higher than baseline rule-based control, in 100 training epochs; GAIL also outperformed PPO by 7%, resulting in 2% lower energy costs and notably improved thermal comfort. This improvement in thermal comfort is evidenced by a reduction of 18.65 unmet degree hours during the one-week operation. In comparison, PPO requires more training time and still lags behind GAIL in cumulative reward even after 500 epochs. These findings highlight the advantages of GAIL in enabling faster learning with fewer training samples, resulting in cost-effective solutions due to lower computational requirements. Overall, GAIL presents a promising approach to building energy management and provides a practical and flexible solution to the shortcomings of learning-based controllers that require extensive computational resources and training time.

Prediction models for building thermal mass of intermittently heated rooms for balancing energy consumption and indoor thermal comfort

Building thermal mass (BTM) plays an essential role in maintaining a comfortable indoor environment for intermittently heated rooms (IHR). However, how to properly determine the BTM in IHR is unclear for the comprehensive consideration of the opposite effects on the reduction of heating energy consumption (HEC) as well as the improvement of indoor thermal comfort (ITC). This study aims to investigate the comprehensive impact of BTM on the HEC and ITC of IHR in the hot summer and cold winter (HSCW) zone of China using the validated EnergyPlus model. The results indicate that BTM can significantly improve the ITC of IHR, whereas increase HEC. The degree of impact is mainly related to the internal wall heat accumulation coefficient, external wall insulation layer thermal resistance, and outdoor air mean temperature during non-heating periods. Response surface methodology is further employed to quantify the effects of BTM on HEC and ITC of IHR. Based on the predictive models, the range of parameter variations for BTM that simultaneously meet HEC and ITC requirements is obtained. The predictive models can provide a theoretical basis for balancing HEC and ITC in intermittently heated buildings in the HSCW zone of China.

Biomimetic Facade Design Proposal to Improving Thermal Comfort in Hot Climate Region

Biomimetic Facade Design Proposal to Improving Thermal Comfort in Hot Climate Region

Recent Advances and Developments in Phase Change Materials in High-Temperature Building Envelopes: A Review of Solutions and Challenges

The use of phase change materials (PCMs) has become an increasingly common way to reduce a building’s energy usage when added to the building envelope. This developing technology has demonstrated improvements in thermal comfort and energy efficiency, making it a viable building energy solution. The current study intends to provide a comprehensive review of the published studies on the utilization of PCMs in various constructions of energy-efficient roofs, walls, and ceilings. The research question holds massive potential to unlock pioneering solutions for maximizing the usefulness of PCMs in reducing cooling demands, especially in challenging high-temperature environments. Several issues with PCMs have been revealed, the most significant of which is their reduced effectiveness during the day due to high summer temperatures, preventing them from crystallizing at night. However, this review investigates how PCMs can delay the peak temperature time, reducing the number of hours during which the indoor temperature exceeds the thermal comfort range. Additionally, the utilization of PCMs can improve the building’s energy efficiency by mitigating the need for cooling systems during peak hours. Thus, selecting the right PCM for high temperatures is both critical and challenging. Insulation density, specific heat, and thermal conductivity all play a role in heat transfer under extreme conditions. This study introduces several quantification techniques and paves the way for future advancements to accommodate practical and technical solutions related to PCM usage in building materials.

Development of bio-based lightweight and thermally insulated bricks: Efficient energy performance, thermal comfort, and CO2 emission of residential buildings in hot arid climates

This study explores the viability of using industrial wastewater sludge (IWWS), generated by the mycelium treatment of dyeing wastewater, for the fabrication of lightweight and thermally insulating bricks. The pulverized IWWS was used at various replacement ratios of 0, 5, 10, 15, and 20 wt% of clay. The mixture was subjected to firing temperatures of 700, 800, and 900 °C. The effect of applying IWWS to the brick characteristics is assessed through an examination of the physico-mechanical and thermal properties. The utilization of IWWS resulted in a significant enhancement in apparent porosity (34.4 %), cold water absorption (25.6 %), boiling water absorption (28.5 %), linear drying shrinkage (5.1 %), and linear firing shrinkage (7.9 %) using 20 % IWWS at 900 °C. Furthermore, the density, compressive strength, and thermal conductivity were reduced as the substitution IWWS ratio increased, reaching up to 1662.9 kg/m3, 11.56 MPa, and 0.198 W/m.K., respectively, using 20 wt% IWWS at 900 °C. The effect of fabricated fired bricks (FBs) on the thermal insulation, CO2 emissions, and energy consumption of residential buildings was tested. This is accomplished by using energy modeling tools, such as Honeybee, Ladybug, and Climate Studio (Grasshopper plugins), in addition to Galapagos for optimizing wall design. The suggested wall design is being used in a communal residential building located in two distinct climatic regions, namely Cairo in Egypt and Jazan in Saudi Arabia. According to the projected mean vote (PMV) and anticipated percentage of discontent (PPD) measures, the utilization of fabricated FBs as wall materials exhibits significant improvements in thermal comfort. Furthermore, they lead to a 6 % and 7 % drop in CO2 emissions in Cairo and Jazan cities, respectively, as well as a significant 38.8 % and 39 % reduction in energy consumption in Cairo and Jazan cities, respectively. Therefore, the use of fabricated FBs demonstrates itself as a feasible and environmentally friendly choice for building construction.

Multi-fanning and its improvement of thermal and wind comfort: An auxiliary means to air conditioning

Space cooling has led to an increase in building energy consumption and the incidence of issues related to indoor air quality. Faced with these challenges, the use of dynamic airflow has become a major area of interest in order to create a comfortable, healthy, and sustainable environment. However, it is revealed that previous studies mostly used single air sources to supply airflow uni-directionally, studying their thermal comfort performance mainly at background temperatures below 30 °C. Considering the dynamic velocity and direction characteristics of outdoor natural wind, in this study, we designed twelve wind conditions and analyzed their airflow characteristics and comfort evaluation. The analysis results revealed that multi-fanning airflows had more dynamic velocity and direction characteristics than directly-supplied constant mechanical wind. Besides, twenty subjects participated in this experiment, they were exposed to these twelve wind conditions at two background temperatures of 31 °C and 32 °C. The findings indicated that, other than the air velocity, the diversity of incoming airflows’ direction was also of utmost importance in affecting wind comfort. According to the thermal and wind comfort evaluations, it was found that a diversified use of electrical fans can still maintain great wind comfort without sacrificing thermal comfort in hot environments (up to 32 °C). This study recommended the multi-fanning cooling scenario as an auxiliary means to air conditioning. It might not only help mitigate anthropogenic emissions to achieve carbon neutrality but also be greatly beneficial to the comfort, health, and well-being of occupants.

The Effect of Green Stormwater Infrastructures on Urban-Tier Human Thermal Comfort—A Case Study in High-Density Urban Blocks

Green stormwater infrastructure (GSI) is a key approach to greening and cooling high-density blocks. Previous studies have focused on the impact of a single GSI on thermal comfort on sunny days, ignoring rainwater’s role and GSI combinations. Therefore, based on measured data of a real urban area in Nanjing, China, this study utilized 45 single-GSI and combination simulation scenarios, as well as three local climate zone (LCZ) baseline scenarios to compare and analyze three high-density blocks within the city. Among the 32 simulations specifically conducted in LCZ1 and LCZ2, 2 of them were dedicated to baseline scenario simulations, whereas the remaining 30 simulations were evenly distributed across LCZ1 and LCZ2, with 15 simulations allocated to each zone. The physiological equivalent temperature (PET) was calculated using the ENVI-met specification to evaluate outdoor thermal comfort. The objective of this research was to determine the optimal GSI combinations for different LCZs, their impact on pedestrian thermal comfort, GSI response to rainwater, and the effect of GSI on pedestrian recreation areas. Results showed that GSI combinations are crucial for improving thermal comfort in compact high-rise and mid-rise areas, while a single GSI suffices in low-rise areas. In extreme heat, rainfall is vital for GSI’s effectiveness, and complex GSI can extend the thermal comfort improvement time following rainfall by more than 1 h. Adding shading and trees to GSI combinations maximizes thermal comfort in potential crowd activity areas, achieving up to 54.23% improvement. Future GSI construction in high-density blocks should focus on different combinations of GSI based on different LCZs, offering insights for GSI planning in Southeast Asia.

Influence of a Built-in Finned Trombe Wall on the Indoor Thermal Environment in Cold Regions

This study focuses on energy conservation, reducing the amount of energy consumed to heat a room, and decreasing the intensity of carbon emissions. The research object is a room heated by a floor with a built-in finned Trombe wall (TW) located in Lanzhou, Gansu Province. ANSYS software was employed to conduct a simulation study on parameters such as fin height, transverse spacing, longitudinal spacing, arrangement mode, and fin apex angle. The simulation results were used to determine the fin parameters’ thermal impact on the TW’s thermal performance, including with respect to a room’s thermal environment (TE). The results show that the heat transfer performance of a TW with respect to the thermal environment of a room is the greatest when the height of the heat-absorbing surface is 20 mm, the transverse spacing is 0.20 m, the longitudinal spacing is 0.533 m, and in-line 90° top-angle fins, that is, isosceles right triangle fins, are used. The average Nu number of the fin-type TW is 154.75. Compared with the average Nu number of the finless TW, which is 141.43, the average Nu number increases by 13.32 due to the addition of fins. The optimized fin-type TW has 7.77% higher convective heat supply efficiency than the finless TW. Although the PMV-PPD results of the two TW-type rooms are not very different, the comfort period of the fin-type TW room is longer. At the same time, the LPD3 of the non-finned TW and the finned TW rooms is less than 10%, the wind speed at the head and ankle is less than 0.12 m/s, the air gust sensation is not strong, and the thermal comfort is good, indicating that the addition of fins is beneficial to the improvement of indoor thermal comfort. Compared to standard rooms, finless TW rooms and fin-type TW rooms have energy-saving rates of 36.38% and 44.63%, respectively. Thus, fin-type TW rooms’ energy saving rate is 8.25% higher, resulting in effective savings in heating energy consumption. Therefore, the indoor TE and auxiliary heating conditions are improved, and the integration of solar building technology can be facilitated, which offers significant reference value for energy transformation.

Energy retrofit technology for modern and contemporary educational historical buildings considering preservation and utilization aspects

Energy retrofit technology is proposed for achieving continuous and efficient energy utilization in modern educational facilities. To improve the accuracy of diagnosis rather than improving numerical analysis, the building performance evaluation of exterior walls and windows was conducted using on-site measuring equipment. The target building had a substandard domestic performance; therefore, improvement measures were required to use building energy efficiently. We evaluated the energy consumption of the target building through the building energy analysis program DesignBuilder. Energy efficiency and economic benefits of retrofit technologies were evaluated, with seven selected technologies categorized into passive, active, and renewable. Efficient technologies included PV panel, High-efficiency HVAC system, Airtight film, and LED lights. 8 retrofit packages were formulated, considering energy savings, economic viability, and thermal comfort improvements. Among these, the energy-saving package, the package incorporating all technologies, the economically beneficial package, and the conservation package were efficient for energy savings, while the conservation package, the economic benefits, and the passive were economically efficient. energy-saving package was found effective for warm improvement and demonstrated significant improvement in cold thermal comfort conditions. Considering the modern nature of the target building, a comprehensive conservation package was deemed most suitable, offering energy savings, economic benefits, thermal comfort enhancements, and preservation aspects. With a payback period of 4 years and achieving a 41.4% energy saving, it was deemed the optimal choice for the target building.

Operational performance of PCM embedded radiant chilled ceiling using a rule-based control strategy

The increasing energy demand for space cooling, projected to triple by mid-century and surpassing a quarter of today's global electricity usage, underscores the urgent need for innovative, more energy-efficient air-conditioning technologies. The research introduces phase change material (PCM) embedded radiant cooling (PCM-RCC) as a promising solution, offering enhanced energy efficiency and indoor environmental quality. Despite its potential, PCM-RCC remains in the developmental stage, requiring further research to fully unlock its benefits. This work aims to analyse the operational performance of PCM-RCC and develop an advanced rule-based control strategy to enhance its efficiency further. The analysis was conducted using a validated PCM-RCC transient system simulation model. To quantify the advantages of PCM-RCC over typical radiant cooling and evaluate the effectiveness of the proposed control strategy, two reference cases are defined: (1) basic-controlled PCM-RCC, and (2) radiant cooling without PCM. Results reveal that PCM-RCC with advanced control demonstrates higher load flexibility (∼93% off-peak time operation), 12% less electricity usage, a 5% coefficient of performance improvement, and a 30% decrease in operational costs compared to radiant cooling. Furthermore, the proposed system shows 9% lower energy usage with a 20% improvement in thermal comfort compared to basic-controlled PCM-RCC.

A Study on the Effect of Green Plot Ratio (GPR) on Urban Heat Island Intensity and Outdoor Thermal Comfort in Residential Areas

Greenery impacts the urban thermal environment, but the benefits of the three-dimensional green volume of space have not been effectively evaluated. In this paper, we analyzed the impact of 3D greenery on urban heat island intensity and thermal comfort in residential areas from the perspective of the green plot ratio (GPR). We selected a typical residential area, set up simulation models, and then analyzed the effect of different GPR values on the outdoor thermal environment using the validated ENVI-MET simulation. The results showed that increasing GPR in residential areas can effectively reduce the intensity of urban heat island and improve thermal comfort. When the GPR reaches 0.5 and 1.5, the thermal comfort level of the building overhead space and the north–south street space decreases from “very strong thermal stress” to “strong thermal stress”. When the GPR reaches 2.5, the outdoor thermal comfort of the east–west street space and courtyard space is reduced to “hot”. When the GPR is higher than 0.5, the urban heat island intensity in the north–south street space decreases by one level, from “very strong” to “strong”. When the GPR reaches 3.5, all four types of spaces have “moderate” urban heat island intensity. Increased GPR exacerbates urban heat island intensity to some extent and worsens outdoor thermal comfort due to the nocturnal insulating effect of plants. Based on the results, the study proposes the bottom-line control of the GPR index from the perspective of urban heat island mitigation and thermal comfort improvement. This paper points out the benefits of GPR in residential areas in improving the human environment, which is of great practical value for developing urban residential environment from “increasing quantity” to “improving quality”.

Influence of Sun Shading Devices on Energy Efficiency, Thermal Comfort and Lighting Comfort in a Warm Semi-Arid Dry Mediterranean Climate

The dry Mediterranean climate (BShs) is the European region with the highest number of hours of sunshine per year. The high annual solar radiation makes sun shading devices necessary to comply with current energy efficiency standards. However, these standards do not sufficiently consider their effect on the indoor lighting comfort of buildings. The objective is to qualitatively and quantitatively determine how movable sun shading devices jointly influence the energy efficiency, thermal comfort and lighting comfort of buildings in BShs climate. The scientific novelty of the work consists of demonstrating the limitations of the sun shading systems commonly used in southeastern Spain and determining the optimal technical solution in this climate to simultaneously improve thermal and lighting comfort. This research comparatively studies the influence of various movable sun shading systems on the daylighting and thermal performance of an educational building. This study conducted on-site measurements, user surveys and computer simulations to study how to improve the thermal and lighting performances of the building. This work demonstrates that interior solar shading provides little improvement in thermal comfort and reduces the cooling demand by only 25%. External movable sun shading improves thermal comfort and reduces the cooling demand by more than 60%, but only adjustable blinds or awnings achieve adequate and homogeneous illuminance values as they diffuse daylight. The paper concludes that energy efficiency standards should be modified to ensure adequate lighting comfort in buildings.

Relationship between Cooling Methods and Energy Consumption for the Development of Low-Carbon Collective Housing in Indonesia

Indonesian urban population increase has led to increased energy demands and housing inventory shortages. The Ministry of Public Works and Housing (PUPR) supplies collective housing for low-income communities (MBR). The development of low-carbon collective housing has been thought to suppress the abrupt increase in household-sector energy demand and lead to mitigated greenhouse gas (GHG) emissions. In tropical climates, it is essential to reduce the dependence on air conditioners (AC) to suppress energy consumption. Therefore, to investigate the relationship between cooling methods and energy consumption, this study surveyed the energy consumption per household and classified the existing cooling patterns of ACs, fans, and window openings in collective housing with different income groups in Indonesia. The results confirmed that the use of AC increases household energy consumption. Meanwhile, the implementation of natural ventilation (NV) showed significantly lower energy consumption with a high thermal satisfaction of more than 80% during the day and 90% at night; thus, both energy consumption reduction and indoor thermal comfort improvement could be achieved through these methods. The findings of this study serve as a starting point for verifying the energy saving effects of air conditioning habits with the consideration of socio-demographic changes for the purpose of decarbonizing collective housing, including future predictions and energy simulations.

Developing a novel personal thermoelectric comfort system for improving indoor occupant’s thermal comfort

Personal comfort systems (PCSs), which target to condition only the occupied zones of indoor space, have received considerable interest due to their validity in thermal comfort improvement and building energy saving. Recently, the thermoelectric module (TEM) has been utilized in the design of PCS for its high reliability, small size and noise-free operation. However, the PCSs using the TEM generally lack the effective control strategy with occupant’s feedback, thus reducing their actual effectiveness on improving thermal comfort. In this paper, a novel personal thermoelectric comfort system (PTCS) is developed with a feedback control framework embedded into it. The PTCS is mainly composed of a thermoelectric conversion unit, a micro blower, control/drive modules and a tube network. A thermal comfort feedback control strategy is proposed for the PTCS. In this strategy, a thermal comfort feedback table is established based on offline experiments, and the tube outlet airflow velocity and temperature setpoints are obtained simultaneously through the table look-up method. Then, the neuron PID control algorithm and pulse width modulation (PWM) of voltage are adopted to adjust the tube outlet airflow velocity and temperature for tracking the obtained setpoints. Experimental results validate the effectiveness of the thermal comfort feedback control strategy. Thermal imaging results on human body demonstrate the availability of the developed PTCS. Performance comparison with other PCSs is also provided, which indicates the potential for practical applications.

Shading Strategies for Outdoor Waiting Areas in Hot Climates: Improving Thermal Comfort and Healing Environments in the Post-Pandemic Era

Shading Strategies for Outdoor Waiting Areas in Hot Climates: Improving Thermal Comfort and Healing Environments in the Post-Pandemic Era

Balancing thermal comfort and energy efficiency in high-rise public housing in Hong Kong: Insights and recommendations

As global warming intensifies, passive design for public housing in hot and humid climates has become a pressing issue. Achieving a balance between thermal comfort and energy conservation is particularly challenging in low-income public rental housing, where residents may endure extended periods of uncomfortable and unhealthy thermal conditions without resorting to air conditioning. In this study, EnergyPlus simulations are employed in combination with a novel thermal-comfort-based HVAC control approach to evaluate the performance of 14 Passive Cooling Strategies (PCS) in optimizing thermal comfort and energy conservation in high-rise public apartments of various sizes and orientations in Hong Kong, particularly under extreme summer conditions. The results reveal that, during extreme summer weather, the implementation of PCS primarily enhances thermal comfort conditions in May and September, while facing challenges in creating comfortable conditions during peak summer months. Most PCSs struggle to improve indoor comfort while simultaneously reducing energy consumption, with two exceptions: 1) Cross-ventilation-based designs enhance thermal comfort without increasing cooling energy consumption. 2) With energy-saving HVAC and opening control behavior, coupled with the use of fans for improving indoor thermal comfort, all PCSs can achieve a simultaneous improvement in thermal comfort and a reduction in cooling energy consumption. This results in a reduction in summer air-conditioning operation time of up to 50% and a decrease in air-conditioning cooling energy consumption of up to 30%. Regarding the impact of building size and orientation: 1) Small apartments show a heightened sensitivity to PCSs, particularly concerning indoor temperature, thermal comfort, and cooling energy consumption. 2) The influence of building orientation on cooling and comfort time in any PCS varies by less than 10% of its average and is even lower in PCSs with lower internal heat gain.