Cold Winter Climate Zone Research Articles

Simulation and Analysis of Factors Influencing Climate Adaptability and Strategic Application in Traditional Courtyard Residences in Hot-Summer and Cold-Winter Regions: A Case Study of Xuzhou, China

Residential buildings consume significant amounts of energy worldwide. Traditional courtyard houses have substantial energy-saving potential due to their low energy consumption and high climate adaptability, which has heightened interest in their climate-responsive design. In recent years, extensive research on traditional houses has been conducted in China, indicating significant variations in energy performances among traditional courtyards within hot-summer and cold-winter climate zones. Therefore, this study, based on research conducted on traditional courtyard houses in the Xuzhou area and utilizing Ecotect and Phoenics ecotechnology software for simulation analysis, comparatively examines the factors influencing energy consumption to assess the energy-saving potential of these houses in hot-summer and cold-winter climate zones. Research has indicated that when traditional Xuzhou courtyard houses meet certain criteria—including an orientation of 20° east of south for the main building, width-to-depth ratio of 2:1, roof slope of 35°, courtyard width-to-depth ratio of 1.7:1, use of branch pick windows, building height of 4.5 m, and a specific window-to-wall ratio—they achieve optimal climate adaptability. This study proposes dimensions for traditional residential buildings suited to the Xuzhou climate and explores their practical application, providing targeted optimization and retrofitting suggestions to support sustainable architectural and ecological development.

Analysis of the Applicability of a Phase-Change Energy Storage Wall for Public Buildings in Hot Summer and Cold Winter Climate Zones

The effects of applying a phase-change energy storage wall in office buildings in hot summer and cold winter climate zones were analyzed by comparing several factors based on numerical calculations, specifically focusing on the internal and external wall temperature, delay time, attenuation multiple, and building load. It was found that the most effective phase-change temperature was 30 °C and the optimal thickness for the phase-change layer was 30 mm. The adoption of the outer phase-change wall layout improved the heat insulation performance during the summer. This effectively enhanced the energy-saving effect of the phase-change layer thickness and layout, which aligns with the influence law of phase-change wall heat transfer.

Effects of solar energy absorbed by south wall on carbon emission from space heating in hot summer-cold winter region

Carbon emission caused by space heating (CEH) in hot summer and cold winter climate zone has increased dramatically. Taking advantage of the solar energy absorbed by south wall (SEASW) can effectively reduce CEH, however, the accurate quantification of its impact remains a challenge. The study investigates the potential of SEASW in mitigating CEH. Key parameters affecting CEH, such as sunny day ratio, insulation form, and outer surface heat transfer coefficient of south wall (h), were analyzed. Results show the reduction in carbon emissions caused by the solar energy absorbed by each unit area of the south-facing wall (ΔCreduction) can be as high as 18.61 kgCO2⋅m−2 for the wall employing internal insulation and smaller h. A prediction model of ΔCreduction was further developed by using multivariate nonlinear regression, which can estimate the reduction in CEH for different fuels as heating source by a south wall in different sizes. Besides, the potential of SEASW on the reduction of carbon emission per unit floor area can reach 12.2 %. This study underscores the importance of SEASW as a carbon-neutral heating strategy, particularly for regions characterized by short winter heating periods and lower heating loads compared to colder climates. It provides valuable insights for sustainable energy practices and policy formulation.

Field measurement study of indoor thermal environment of badminton halls in a hot summer and cold winter region in different seasons in China

The indoor thermal environment has a direct impact on human thermal comfort and health. In order to assess the status of the indoor thermal environment of typical sports buildings in hot summer and cold winter climate zones in China, 14 badminton halls in 10 cities in Hubei Province (including 5 venues in Wuhan) in this climate zone are chosen as research objects for field testing of indoor thermal environment parameters in 4 seasons. All the tested stadiums are naturally ventilated in non-event conditions. The results reveal that the average indoor temperature of badminton halls in summer is excessively high (i.e., 31.89 °C), which is higher than the regulation specified in JGJ31-2003 or GB-T18883-2022 on the reference interval of the indoor air temperature of venues in summer, (i.e., (26–28 °C) or (22–28 °C), respectively). The average indoor temperature of badminton halls in winter is too low (i.e., 12.95 °C), and it is lower than the recommendations of JGJ31-2003 or GB-T18883-2022 on the reference interval of the indoor air temperature of venues in winter (i.e., (16–18 °C) or (16–24 °C), respectively), relative humidity and air velocity are in the thermal comfort interval for all seasons, and the indoor thermal environment factors of badminton courts in spring and autumn meet the comfort requirements. The indoor and outdoor temperatures and the relative humidity of badminton courts are highly correlated. The indoor temperature and relative humidity vary according to changes in those factors outdoors, whereas the air velocity is not affected by outdoor changes. In the hot summer and cold winter climate zones, some discrepancies in the indoor temperature variation patterns of badminton halls at various altitudes are detectable. The results of this study aim to provide a solid basis for the development of indoor thermal-comfort standards for sports stadiums in China.

Enhancing energy efficiency of PCM wall in winter with novel PCM-DLCB coupling design

In order to enhance the thermal performance of the phase change material (PCM) wall during winter, a novel PCM and double-layer capillary bundles (PCM-DLCB) coupling wall is proposed. The PCM-DLCB wall utilizes the capillary bundle near the outer surface to capture solar energy during sunny winter days. The heat is then transferred to the capillary bundle near the inner surface through a circulating pump, promoting the melting of the PCM. Optimization and long-term operation comparison research were conducted using numerical simulation to investigate the potential of the PCM-DLCB wall to improve energy efficiency during winter. Five structural parameters, including the type of PCM, the position of the capillary bundle, the position and thickness of the PCM layer, the spacing of the capillary bundles, and the flow velocity in the capillary bundle, were selected as variables for structural and operation optimization. The optimization target was the accumulated heat gain from the inner surface of the wall. The research results indicate that: (1) The most suitable PCM is RT-18HC; (2) Placing the PCM layer between the double-layer capillary bundle yields better results compared to other arrangements; (3) Optimal energy saving is achieved when the outer capillary bundle is positioned 6 mm away from the outer surface and the inner capillary bundle is positioned 8 mm away from the inner surface; (4) The optimal thickness of the PCM layer is 10 mm; (5) The optimal flow velocity in the capillary bundle is approximately 0.04 m/s. Furthermore, long-term operation results based on a typical hot summer and cold winter climate zone reveal that the optimized PCM-DLCB wall provides a 7.80 % increase in indoor heat gain compared to an ordinary PCM wall during winter, and an 18.4 % increase compared to a wall without PCM.

System reliability study of geothermal energy walls in subway stations based on rapid thermal performance prediction model

The energy conservation potential of relative systems in subway stations can be improved via the implementation of energy walls. However, current research mainly focuses on analyzing the factors affecting the energy walls' heat transfer performance, neglecting the reliability and performance assessment for ground source heat pump systems based on energy walls. This paper focuses on a subway station in hot-summer and cold-winter climate zone. Initially, both a resistance-capacity model and a 3D finite element model of energy walls are established. The resistance-capacity model is validated to be integrated with heat pump units to propose the rapid system performance prediction. Subsequently, the system thermal performance with the input of dynamic loads and conventional operational strategies is investigated. The results reveal that due to the heating and cooling load imbalance, the system inevitably experiences thermal imbalances and enters an inefficient operational state by the 6th year. Finally, to address this issue, a hybrid heat pump system with cooling towers is proposed, which demonstrates better thermal performance when used during non-cooling seasons. Another hybrid heat pump system for simultaneous cooling and heating is also proposed. These approaches both delay the onset of the system's inefficient operational state by 1–2 years, thereby improving the thermal performance.

Energy and economic performance optimization of a window with variable transparency shape-stabilized PCM in hot summer and cold winter climate zone

Improving the thermal performance of windows is important for building energy efficiency. Filling windows with variable transparency shape-stabilized phase change materials (VTSS-PCM) improves the thermal inertia of windows while avoiding the leakage of PCM. In this paper, a new type of VTSS-PCM window was proposed, tested, simulated and optimized in hot summer and cold winter climate zone. A numerical model of the VTSS-PCM window was built, and the model was validated using experimental tests. On this basis, three key parameters of VTSS-PCM were investigated and optimized. Finally, the energy and economic performance of the optimized VTSS-PCM window were compared with a typical hollow glass window. The results showed that the total annual unfavourable heat transfer (TAHT) and the annual investment cost (AIC) of the VTSS-PCM window obtained from the optimization were 118.16 kWh/m2 and 8.53 CNY/m2, respectively. Compared with the hollow glass window, the VTSS-PCM window reduced the TAHT by 30.14% and the total annual cost by 28.39%. The VTSS-PCM window produced a better development potential in terms of energy performance and economic performance. This study provided a reference for the application of the VTSS-PCM window in hot summer and cold winter regions of China.

Research Optimizing Building Ventilation Performance through the Application of Trombe Walls in Regions with Hot Summers and Cold Winters: A Case Study in China

The hot-summer and cold-winter climate zone spans a large latitude, where the passive means of retrofitting the Trombe wall (TW) can be utilized to effectively improve the indoor wind environment and thermal comfort. In this study, a public building in Wenzhou, China, was selected as the object, and CFD numerical simulations and the wind environment data in spring, summer, and fall were collected through field experimental measurements. Comparative analyses were carried out to explore the adaptive strategy and effectiveness of the application of the Trombe wall on the local wind environment and climate and to quantify the improvement effect of the application of the Trombe wall on the Indoor environment. The results showed that the application of the Trombe wall in spring and fall in hot-summer and cold-winter regions could obviously increase the average indoor wind speed and the wind speed at the building outlet by 0.2–0.8 m/s and 0.9–3.6 m/s, respectively. This further effectively prolongs the indoor thermal comfort hours in spring and fall, which is a relatively applicable season, while the ventilation performance in summer is poor compared to spring and fall seasons.

Morphology Optimization of Residential Communities towards Maximizing Energy Self-Sufficiency in the Hot Summer Cold Winter Climate Zone of China

Further research is needed on the capability of residential communities to achieve energy self-sufficiency under the constraints of current standards of land use, in particular for the Hot Summer and Cold Winter climate zone (HSCW) of China, where the majority of communities are dominated by high floor-area ratios, thus high-rise dwellings, namely less solar potential per unit floor area, while most residents adopt a “part-time, part-space” pattern of intermittent energy use behavior, thus using relatively low energy per unit floor area. This study examines 150 communities in Changsha to identify morphological indicators and develop a prototype model utilizing the Grasshopper platform. Community morphology is simulated and optimized by taking building location, orientation, and number of floors as independent variables and building energy consumption, solar PV generation, and energy self-sufficiency rate as dependent variables. The results reveal that the morphology optimization can achieve a 4.26% decrease in building energy consumption, a 45% increase in PV generation, and a 13.2% enhancement in energy self-sufficiency, with the optimal being 39%. It highlights that energy self-sufficiency cannot be achieved solely through morphology improvements. Moreover, the study underscores the crucial role of community orientation in maximizing energy self-sufficiency, with the south–north orientation identified as the most beneficial. Additionally, a layout characterized by a horizontally closed and staggered pattern and a vertically scattered arrangement emerges as favorable for enhancing energy self-sufficiency. These findings underscore the importance of considering morphological factors, particularly community orientation, in striving towards energy-self-sufficient high-rise residential communities within the HSCW climate zone of China.

An empirical study of indoor air quality in badminton stadiums in hot summer and cold winter regions of China during spring and fall seasons

The indoor air quality has a direct impact on human health. In order to obtain the current status of indoor air quality in typical sports buildings in hot summer and cold winter climate zones in China, indoor badminton courts in 10 cities in Hubei Province in this climate zone were selected as research objects for field testing of indoor environmental parameters in spring and autumn, and predict air quality parameters for non-testing times. All the tested stadiums are naturally ventilated in non-event conditions, and the average daily indoor CO2 concentration was 526.78 ppm in spring and 527.63 ppm in autumn, and the average daily PM2.5 concentration was 0.035 mg/m3 in spring and 0.024 mg/m3 in autumn, all of which met the requirements of GB/T 18883-2022, the average concentration of CO2 ≤ 1000 ppm and PM2.5 ≤ 0.05 mg/m3. The indoor CO2 concentration and PM2.5 concentration of the tested badminton halls under natural ventilation gradually increased with the accumulation of exercise time, making the indoor air quality of the badminton halls decrease, which would negatively affect the health of the people exercising in this environment.

Analysis of 2D heat transfer of shear wall thermal bridges influencing on the exterior wall

ABSTRACT Frame-shear wall structures are widely used in high-rise buildings, and their thermal bridges account for a large portion of the entire exterior wall area. The purpose of this study was to investigate heat transfer of shear wall thermal bridge (SWTB) that influences the exterior wall of a building. A typical 3D COMSOL model of the SWTB junction was built, and indices were used to quantify its thermal characteristics of the SWTB junction. The results showed that the peak values and peak width of the heat flux at the interface of the exterior wall and thermal bridge increased with an increase in the thermal resistance of the SWTB. When the thermal resistance of the SWTB (R tb ) is greater than or equal to the thermal resistance of the exterior wall (R w ), the influencing area A i n f no longer increases. In addition, the maximum error of replacing K 2D with K 1D discussed in this paper was 3.56%, which can be neglected in engineering applications in hot summer and cold winter climate zones. Finally, strategies to reduce the heat loss of the SWTB were proposed. The results of this study provide valuable data for engineers to evaluate the thermal characteristics of SWTB in building designs.

Retrofit Analysis of City-Scale Residential Buildings in the Hot Summer and Cold Winter Climate Zone

The rising energy consumption in residential buildings within the hot summer and cold winter (HSCW) climate zone, driven by occupants’ pursuit of improved thermal comfort, necessitates effective energy conservation measures. This study established urban building energy models for 32,145 residential buildings in Changsha City, China, and conducted a comprehensive retrofit analysis of seven energy conservation measures (ECMs). Additionally, the study assessed the impact of residents’ conscious energy-saving behaviors concerning air conditioner (AC) control. The research commenced by creating six baseline models representative of the diverse building stock. Identifying seven commonly used ECMs, the study examined the potential of each measure for enhancing energy efficiency. To facilitate the analysis, a dedicated toolkit, AutoBPS-Retrofit, was developed to efficiently modify the baseline model for each ECM. Furthermore, the investigation delved into the investment cost of implementing the ECMs and evaluated their simple payback year (PBP) and net present value (NPV). The results demonstrate that tailored retrofit plans are essential when addressing envelope improvements, varying according to building types and ages. Retrofits targeting lighting systems offer both promising energy savings and favorable economic viability, albeit subject to residents’ preferences. Alternatively, upgrading the AC systems emerges as the most energy-efficient approach, yet the economic assessment raises concerns. The study’s findings offer practical insights for governments seeking to establish effective carbon reduction goals and policies. Moreover, the research can assist energy-saving institutions, real-estate companies, and stakeholders involved in renovation projects by offering guidance in making informed decisions to enhance energy efficiency in city-scale residential buildings.

Simulation Study on Outdoor Wind Environment of Residential Complexes in Hot-Summer and Cold-Winter Climate Zones Based on Entropy-Based TOPSIS Method

Driven by a large digital simulation environment, CFD calculation software is used to simulate test results so that they can be effectively applied to engineering practice. This paper explores the suitable outdoor wind environment for residential areas in the hot summer and the cold winter. Taking Xishan Huijing in Changsha as an example, the most unfavorable wind field environment is used as the boundary condition, and the optimal design mode for this residential area is explored based on the Butterfly platform. The research in this paper is mainly divided into five steps: (1) using Rhino 7.0 to establish a 3D model; (2) using the Butterfly 0.0.05 platform to simulate the wind field and export the data at the same time, and to realize the preview through the visualization method; (3) processing the exported simulation data and the calculation of related indices; (4) applying the entropy-based TOPSIS method on the MATLAB 2020 platform to rank the preferred scheme and obtain the corresponding index weights; and (5) using a K-means cluster analysis on SPSS 26 software to optimize the scheme. The results show that (1) the wind environment quality will be overestimated in the summer if the influence of neighboring buildings on the site is not considered, while the opposite is true in the winter, with the error of both reaching two times. (2) The weights of the indicators determined by the TOPSIS entropy weighting method indicate that wind protection in the winter should be prioritized over natural ventilation in the summer in this area. The maximum wind speed in the winter has the most significant weight, reaching 0.287, and the uniformity of the wind field in the summer is the most important, reaching 0.1102. (3) In the layout design of the residential district, the staggered layout of the 60 m high slab houses in the northern, northeastern, and northwestern directions of the site creates a better wind field environment, which attains the highest score by the TOPSIS entropy weighting method, reaching 0.1539, with the second highest score, reaching 0.1511, for the layout method. The research results will provide a scientific basis for the design of residential buildings in the hot-summer and cold-winter regions in China, and also help designers to better grasp the outdoor wind environment of residential buildings in the pre-design stage.

Multi-Objective Optimization of Ultra-Low Energy Housing in Hot Summer Cold Winter Climate Zone of China Based on a Probabilistic Behavioral Model

Occupant behavior has an important impact on building energy consumption, and the accuracy of an occupant behavior model directly affects the reliability of energy consumption simulation results. Ultra-low energy buildings are crucial to achieving building energy conservation and carbon dioxide reduction in China. In order to effectively promote the development of ultra-low energy buildings in Hot Summer and Cold Winter Climate Zones. where most residents adopt a “part-time, part-space” pattern of intermittent energy use behavior, and to solve the problem of poor indoor thermal environments and the high incremental cost of ultra-low energy, the study described in this paper takes Changsha as an example to carry out a multi-objective optimization study on ultra-low energy housing using a probabilistic behavioral model. On the basis of a probability model representing the residents’ actual behavior in Changsha, the optimization objective indicators, key variables and the technology benchmarks for ultra-low energy building were determined, then multi-objective optimization was carried out for a range of energy efficient technologies to obtain the Pareto optimal solutions. The results showed that the set of optimal solutions could reduce energy demand by 50.2 to 60.2% and reduce indoor thermal discomfort time by 3.52–11.09% compared with those of a reference base case, which just meets the requirements of the current design standard for energy efficient domestic buildings. An optimum solution for energy savings and indoor thermal comfort, along with economic costs, was identified, which can assist in decision-making by providing different preferences and provide useful reference for the design of ultra-low energy buildings in Hot Summer and Cold Winter Climate regions.

Developing a theoretical framework to assist policymaking for retrofitting residential buildings using system player analysis and causal loop diagrams

Retrofit of urban residential buildings (RURB) has great potential for improving energy conservation and sustainability, but it encounters challenges due to the lack of incentive policy and the unwillingness of residents. The RURB retrofitting process is a complex system involving anthropic factors such as proper definition, components, and unclear problems. This study aims to clarify its complex nature concerning the cognition and interactions of the RURB system so to develop a theoretical framework by applying the system thinking approach of System Player Analysis (SPA) with realistic qualitative data collected from four defined main players in the RURB system. Semi-structured interviews and questionnaire surveys were conducted to collect information from RURB policymakers, designers and engineers, scholars, and residents. The Hot Summer and Cold Winter climate zone (HSCW) in China was selected as the case study area. Roles, outputs, issues, demands, and features of individual RURB system players are revealed with unique local retrofit preferences whilst system cognition is clearly defined to create Causal Loop Diagrams (CLD) for RURB to help understand the interactions between system variables. The discussion based on SPA and CLD results provides valuable suggestions for addressing the identified systemic problems of RURB and an extensive theoretical basis for future retrofitting of residential buildings.

Assessment of space heating consumption efficiency based on a household survey in the hot summer and cold winter climate zone in China

Space heating demand in the hot summer and cold winter (HSCW) climate zone in China has increased rapidly over the past decade. It poses significant challenges for China's electricity supply infrastructure and building decarbonization. This study aims to understand the relative energy efficiency of household space heating and identify potential opportunities to reduce electricity usage at the household level. A stochastic frontier analysis approach is used to quantify the energy efficiency of households' space heating by forming an efficient frontier (minimum requirement of consumption given the characteristics of the household) and by comparing all households against that frontier. The results indicate that the average household space heating efficiency is 0.69. This indicates that households in the HSCW area have the ability to reduce their heating electricity consumption by 31% while still keeping the current level of indoor thermal comfort in the winter. The level of building energy efficiency standards (BEES) is the key factor influencing the space heating savings potential. Thus, Policy choices should focus on revising and optimizing superior BEES, and accelerating energy efficiency retrofits of existing residential buildings in this region.

Operation optimisation of the unsaturated rapid cycling adsorbent bed for effective moisture enrichment: Coupled heat-mass transfer and dynamic adsorption modelling

The unsaturated rapid cycle (USRC) is a potential method for effective water harvesting. The operation mode of USRC, although significant for improving water collection, is seldom investigated for lack of quantitative methods. In this study, we defined adsorption unsaturation Ψ and desorption saturation Φ to characterise the USRC. Subsequently, we constructed performance indices, the effective moisture enrichment rate (EMER) and time-averaged dewpoint increase (TADI) to evaluate the moisture enrichment. The optimisation process was simplified based on the heat-mass transfer analysis. We conducted a case study under summer conditions in Chongqing, a typical city in the hot-summer and cold-winter climate zone. The optimal operation mode of an aluminium fumarate-packed adsorbent bed was verified by the experiments within a relative deviation of 8%, which demonstrates the effectiveness of the optimisation approach. The results show that an operation mode with Φ equal to 32% and Ψ equal to 82% leads to a maximum EMER of the USRC, with an improvement of 4–5 times compared to the nearly saturated rapid cycle. In addition, this case study suggests that a higher desorption temperature, higher adsorbent porosity, and more humid ambient air were conducive to improving the EMER of the USRC.

Climate chamber investigation of the effect of indoor thermal histories on thermal adaptation in different seasons

The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years, which also changes their seasonal thermal adaptations and this has formed feed-back effects to the increasing usage of air conditioning units in this area. To study the seasonal variations of thermal adaptation, the thermal comfort experiments were conducted on two groups of participants. Each groups included 20 participants who had indoor history mainly with natural ventilation (NV group) and air-conditioning (AC group), respectively. The results demonstrated that the thermal sensation vote (TSV) in warm environments did not differ between AC and NV subjects in summer. However, the TSV of AC subjects were much lower than that of NV subjects in the same standard effective temperature and skin temperature in a cold environment in winter. Overall, the participants who spent most of their time in AC space in winter showed a low level of thermal adaptation with a narrower acceptable skin temperature range of 32.6 – 33.5 °C. Thus, this study presents the basic information regarding the seasonal effects on human thermal adaptation due to different long-term indoor thermal histories.

Numerical analysis on the energy performance of the PCMs-integrated thermochromic coating building envelopes

Extreme environmental conditions are inappropriate for the cycling of phase change materials (PCMs) attached to building envelopes and have a negative impact on their energy performance. To solve this problem, therefore, thermochromic (TC) coatings are proposed to improve the energy efficiency of PCMs by regulating solar radiation influence. In this paper, the energy performance analysis of TC-PCM systems was carried out in five different representative climate zones. Simulation findings show that, compared to traditional PCM systems (TR-PCM), in the climate characteristics of Shanghai, the annual energy demand of TC-PCM systems decreases by 42.9 kWh/m2, and the corresponding energy-saving rate is high up to 39.9%. This is because the adaptive solar absorptance of TC-PCM systems could enhance the phase change cycle performance of PCMs to reduce both the cooling and heating energy demand. The results also show that the TC-PCM system, with a switching temperature of 26 °C for TC coatings and a transition temperature of 26 °C for PCMs, could achieve the lowest annual energy demand in the climate characteristics of Shanghai. Finally, we investigated that the TC-PCM system has huge potential for energy-savings in all provinces in hot summer and cold winter climate zones, and the highest energy-savings rate can be as high as 10.2%.

A multi-factor optimization method based on thermal comfort for building energy performance with natural ventilation

Natural ventilation is one of the most potential passive measures to improve the building energy performance. This study introduces a multi-factor optimization method for energy performance of buildings with natural ventilation. To maximize the utilization of natural ventilation, this method uses natural-ventilation strategy (Strategy NV) as the air conditioning system operation strategy. In Strategy NV, the air conditioning system is only on when the natural ventilation cannot fulfill the occupants’ thermal needs. Two thermal comfort models and airflow network model are combined to obtain Strategy NV. Support vector regression is applied to train a surrogate model which is used to predict the annual energy consumption in Strategy NV. Introducing the surrogate model as objective function, particle swarm optimization is used to find the optimal solution. A case study in hot summer and cold winter climate zone is given to verify the feasibility and correctness of this method. The optimal solution has 656 GJ annual energy consumption in Strategy NV, including 254 GJ annual thermal energy consumption. The optimal solution saves annual thermal energy consumption by 21% in Strategy NV comparing with Strategy FT (full time operation strategy within occupied period). The annual thermal energy consumption of the optimal solution in Strategy NV is at least 26% smaller than that of four commonly used building designs in Strategy NV; and it is at least 43% smaller than that of the four commonly used building designs in Strategy FT. The optimal solution has the least total air conditioning hours comparing with the four commonly used building designs.