Search Results (14)

This study evaluates the performance degradation of spray rigid polyurethane foam (RPUF) insulation on reservoir dam structures under multi-physics coupling conditions. Focusing on characteristic environmental exposures in Hot Summer and Cold Winter (HSCW) climate zones, accelerated aging tests simulating coupled temperature–humidity effects were conducted to comparatively analyze the thermal resistance and durability evolution between unprotected and encapsulated RPUF configurations. Scanning electron microscopy (SEM), infrared spectroscopy (IR), and other methods were used to characterize and analyze the structure of RPUF. Research has shown that in HSCW climate zones, the thermal conductivity of RPUF gradually increases with the number of degradation cycles, and the insulation performance decreases, mainly due to the damage of the pore structure caused by temperature aging and the combined effect of moisture absorption aging. In comparison, the RPUF after protection can effectively slow down the rate and degree of decline of its insulation performance. On this basis, a time-varying prediction model for the thermal conductivity of RPUF under long-term service in HSCW climate environments was fitted, providing a scientific basis for the durability evaluation of reservoir dam insulation. Full article

With the intensification of climate challenges driven by rapid urbanization, the microclimate and thermal comfort of residential blocks have attracted increasing attention. Current research predominantly focuses on isolated morphological factors—such as building orientation, layout patterns, and height-to-width ratios—while neglecting the synergistic effects of multifactorial spatial configurations on outdoor thermal comfort. This study addresses this gap by analyzing 36 residential block samples in Wuhan, a representative city in a hot-summer and cold-winter (HSCW) region. Utilizing the Honeybee plugin in Grasshopper (GH) alongside the Universal Thermal Climate Index (UTCI), we simulate outdoor thermal environments to identify critical influencing elements. The results reveal how multifactor interactions shape thermal performance, providing evidence-based design strategies to optimize microclimate resilience in high-density urban contexts. This work advances the understanding of spatial morphology–thermal dynamics and offers practical insights for sustainable residential planning. This study systematically investigates the thermal performance of residential blocks through parametric prototyping and seasonal simulations. Sixteen morphological prototypes were developed by combining four building layout typologies (arrayed, staggered, enclosed, and hybrid) with three critical variables: the height-to-width ratio (HWR), building orientation deviation angle (θ), and sky visibility factor (SVF). Key findings reveal the following: (1) the hybrid layout demonstrates superior annual thermal adaptability when integrating fixed orientation (θ = 0°), moderate H/W = 1, and SVF = 0.4; (2) increased H/W ratios enhance thermal comfort levels across all layout configurations, particularly in winter wind protection; and (3) moderate orientation deviations (15° < θ < 30°) significantly improve microclimate performance in modular layouts by optimizing solar penetration and aerodynamic patterns. These evidence-based insights provide actionable guidelines for climate-responsive residential design in transitional climate zones, effectively balancing summer heat mitigation and winter cold prevention through spatial configuration optimization. Full article

The number of colleges and universities in China has been increasing year by year. University buildings have tremendous energy-saving potential due to their high personnel density and energy consumption demand. However, there is a lack of research and regulations focusing on such buildings and taking functional requirements, operating patterns, and climate conditions into account. In the HSCW zone of China, the overlap of energy consumption peak and universities’ winter and summer vacations will lead to improper or excessive implementation of energy-saving measures in practice. This research study on a university teaching building in Shanghai simulated the energy consumption with EnergyPlus (Version 22.1.0) to compare the variation trend of the building’s energy consumption (heating, cooling and annual energy consumption) under different design parameter settings. The influence of orientation and window–wall ratio on the energy consumption intensity of classrooms of various sizes was analyzed, and design strategies were proposed. The research indicates that the annual energy consumption of educational buildings in hot summer and cold winter areas can be reduced by approximately 44.4% during vacations. However, cooling energy consumption remains 18.0–19.4% greater than heating energy consumption. The energy intensity of classrooms decreases as the space size increases. Medium-sized classrooms, with an energy intensity ranging from 44.2–47.6 kWh/m², require priority in energy-efficient design owing to their considerable quantity and high utilization. The findings offer design suggestions for the optimal orientation and window-to-wall ratios of classrooms of different scales, which can be used as a reference for the design of university teaching buildings and the energy-saving retrofit of existing campus buildings. Full article

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. Full article

In the current context of huge global energy consumption and harsh climatic conditions, the energy efficiency and sustainability of buildings have received much attention. The nearly zero-energy building (nZEB) is a feasible solution for solving the energy crisis in the building sector in recent years, and it is important to study the adaptability of its technology system. However, existing studies have not addressed well the issue of the impact of complex and diverse climates on the technology systems of nZEBs. Secondly, in contrast to residential buildings, nearly zero-energy technology systems for office buildings need to be further developed. This study takes the hot summer and cold winter (HSCW) zone of China as an example and uses numerical simulations and orthogonal experiments to investigate the adaptability of nearly zero-energy office building technology systems under complex and diverse climate conditions. The results show the following: (1) Passive technologies are greatly affected by the complexity and diversity of climates. Optimal envelope thermal parameters tailored to specific zones are identified. Specifically, the optimal level of K_WALL in the CT and HSCWC zones is 0.2 W/(m²·K), and the optimal level of K_WALL in the HSWWT zone is 0.3 W/(m²·K); the optimal level of K_ROOF in the CT zone is 0.15 W/(m²·K), and the optimal level of K_ROOF in the HSCWC and HSWWT zones is 0.25 W/(m²·K); (2) Active technologies do not mainly receive the influence of the complexity and diversity of climates, and ED, HR, and TS measures should be adopted for office buildings; (3) The rational utilization of renewable energy is influenced by local resource conditions. This study evaluates the adaptability of GSHP, ASHP, and BIPV technologies. To better meet the requirements of nearly zero-energy office buildings, it is recommended to adopt GSHP for the CT zone and ASHP for the HCWWT zone. This study will be helpful for the development of nearly zero-energy office building technology systems in other complex and diverse climatic zones. Full article

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. Full article

Solar energy has the advantages of being green, renewable, and energy-efficient. The use of solar energy in buildings can result in significant energy savings, and a great deal of practical and theoretical research has been conducted on solar buildings around the world. Southern Shaanxi belongs to a climate zone with hot summers and cold winters (HSCW). The mean room temperature is 4 °C, and it is lower than 2 °C at night, which greatly exceeds the thermal comfort range that the human body can bear. Aiming at a range of challenges including backward heating methods and low heating efficiency in southern Shaanxi, a fully passive thermal storage wall heating system (TSWHS) is proposed for traditional houses in the area. The specific method is to set up a thermal storage wall (TSW) outside the outer walls on the east, west, and south sides of the residential buildings. The wall is provided with an air exchange port, and there is no glass in the outer area of the doors and windows, which does not affect the normal application. The principle is that after the TSW receives solar radiation, the temperature of the internal HDPE (high-density polyethylene) and the air inside the cavity rises, which raises the interior temperature via the heat transfer and the air exchange port inside the TSW. The hot air inside the thermal wall achieves the purpose of heating. Lastly, through a comparison with the original heating system (OHS), it is confirmed that the TSWHS has certain practicability. According to an experimental simulation, the system can increase the indoor temperature by an average of 5.1 °C in winter and save about 1726.43 kWh of energy, accounting for 27.24% of the energy saving. Full article

Household room air conditioners (RACs) are widely used in residential buildings to maintain an indoor thermal climate in China’s hot summer and cold winter (HSCW) zone. The aggregate utilization of RACs in a region has a great impact on regional energy demand in both the heating and cooling seasons. Classifying household RAC users and identifying their RAC usage demands will contribute to better balanced regional energy management for building energy flexibility. In this study, a data-driven method was proposed to classify the household RAC user groups at the regional level, using running time as an indicator. The results showed that RAC users could be classified into four groups with different RAC usage demands. The Lower Class was determined by the absolute poverty line with the Gini coefficient. In addition, the Upper Class was distinguished through the determination of the scaling region in power-law distribution. At the same time, the similarities and differences between different classes in monthly and hourly periods and the flexibility potential were discussed. The rigid demand was observed in the monthly periods of June, July and August and during the hourly periods of 21:00–22:00 in both the bedroom and living-room. Full article

Considering the comprehensive effect of building carbon emissions, cost savings is of great significance in nearly-zero-energy buildings (NZEBs). Previous research mostly focused on studying the impact of technical measures in pilot projects. The characteristics of different cities or climate zones have only been considered in a few studies, and the selection of cities is often limited. At times, only one city is considered in each climate zone. Therefore, this study selected 15 cities to better cover climate zone characteristics according to the variation in weather and solar radiation conditions. A pilot NZEB project was chosen as the research subject, in which the energy consumption was monitored and compared across different categories using simulated values by EnergyPlus software. Various NZEB technologies were considered, such as the high-performance building envelope, the fresh air heat recovery unit (FAHRU), demand-controlled ventilation (DCV), a high-efficiency HVAC and lighting system, daylighting, and photovoltaic (PV). The simulated carbon emission intensities in severe cold, cold, and hot summer and cold winter (HSCW) climate zones were 21.97 kgCO₂/m², 19.60 kgCO₂/m², and 15.40 kgCO₂/m², respectively. The combined use of various NZEB technologies resulted in incremental costs of 998.86 CNY/m², 870.61 CNY/m², and 656.58 CNY/m². The results indicated that the HSCW region had the best carbon emission reduction potential and cost-effectiveness when adopting NZEB strategies. Although the incremental cost of passive strategies produced by the envelope system is higher than active strategies produced by the HVAC system and lighting system, the effect of reducing the building’s heating load is a primary and urgent concern. The findings may provide a reference for similar buildings in different climate zones worldwide. Full article

Along with the rapid urbanization and economic growth of China over the past decades, the thermal comfort needs of the people in this region have risen dramatically, and at the same time, promoting building energy efficiency is cited as part of the major projects in the 14th five-year plan for energy efficiency improvement. In addition, the outbreak of the COVID-19 epidemic has plunged people into long-term panic, and promoted the entire construction industry to think about a healthier and more sustainable living environment. To respond to the imbalance between energy supply and demand, an optimization analysis based on energy use is developed, assessing the energy efficiency of the window-to-wall ratio (WWR) design and calculating the energy consumption of three different types of residential buildings for both cooling and heating loads as well as for year-round loads. Owing to its harsh climate and huge energy consumption, in this study, the Hot-summer and Cold-winter (HSCW) zone of China was chosen as the experimental setting for the optimization analysis of WWR. Then, in the three main types of residential buildings, including detached houses, multi-story dwellings and high-rise dwellings, a correlation between WWR_S and energy consumption in the cooling season, heating season and year-round was built. The comparisons between the WWR_S and energy consumption for different types of residential buildings are presented. The design optimization recommendation for WWR_S are proposed. It has significant positive meanings for the development of green and sustainably designed residential buildings that offer high levels of thermal comfort and energy efficiency. Full article

According to a Chinese building energy demand report of 2016, building consumption is accelerating at a spectacular rate, especially for urban public buildings. In this study, various design parameters that meet the principle of climate adaptation are proposed to achieve the unity of energy utilization and indoor thermal comfort level. According to the local energy conservation codes, five typical benchmark geometric models were established in Open Studio (Sketch-Up plug-in) for sites representative of various climates, meanwhile, adopting the engine of Energy Plus (EP-Launch) to calculate the instrument definition file (IDF), respectively, for assessing the coupling relationship between energy consumption as well as thermal comfort. Results implied that based on the time proportion (8760 h) that met the level 1 comfort range, total energy reductions of different Chinese climate regions were different. Among them, the severe cold zone (SCZ—Changchun) and hot summer and cold winter zone (HSCW—Shanghai) appeared to have the greatest energy saving potential with 18–24% and 16–19%, respectively, while the cold zone (CZ—Beijing) and mild zone (MZ—Kunming) approximately equaled 15% and 12–15%, and the saving space of the hot summer and warm winter zone (HSWW—Haikou) appeared relatively low, only around 5–7%. Although the simulation results may be limited by the number of parameter settings, the main ones are under consideration seriously, which is further indication that there is still much room for appropriate improvements in the local public building energy efficiency codes. Full article

Achieving comfort in hot summer and cold winter (HSCW) climate zones can be challenging, since the climate is characterized by high temperatures in the summer and relatively colder temperatures in the winter. Courtyards, along with other semi-open spaces such as verandas and overhangs, play an important role in mitigating outdoor climate fluctuations. In this research, the effects of courtyards on the thermal performance of vernacular houses in HSCW climate zones were studied via field measurements and computational fluid dynamics (CFD) models. The selected courtyard house was a representative vernacular timber dwelling situated in the southeast of Chongqing, China. The indoor and outdoor air temperature measurements revealed that the courtyard did play an active role as a climatic buffer and significantly reduced the temperature’s peak value in the summer, while during the winter, the courtyard prevented the surrounding rooms from receiving direct solar radiation, and thus to some extent acted as a heat barrier. The contributions of thermal mass are quite limited in this area, due to insufficient solar radiation in winter and general building operations. The natural ventilation mechanism of courtyard houses in HSCW zones was further studied through CFD simulations. The selected opened courtyard was compared to an enclosed structure with similar building configurations. The airflow patterns driven by wind and buoyancy effects were first simulated separately, and then together, to illustrate the ventilation mechanisms. The simulation results show that the courtyard’s natural ventilation behavior benefited from the proper openings on ground level. Full article

Existing thermal comfort field studies are mainly focused on the relationship between the indoor physical environment and the thermal comfort. In numerous chamber experiments, physiological parameters were adopted to assess thermal comfort, but the experiments’ conclusions may not represent a realistic thermal environment due to the highly controlled thermal environment and few occupants. This paper focuses on determining the relationships between upper extremity skin temperatures (i.e., finger, wrist, hand and forearm) and the indoor thermal comfort. Also, the applicability of predicting thermal comfort by using upper extremity skin temperatures was explored. Field studies were performed in office buildings equipped with split air-conditioning (SAC) located in the hot summer and cold winter (HSCW) climate zone of China during the summer of 2016. Psychological responses of occupants were recorded and physical and physiological factors were measured simultaneously. Standard effective temperature (SET*) was used to incorporate the effect of humidity and air velocity on thermal comfort. The results indicate that upper extremity skin temperatures are good indicators for predicting thermal sensation, and could be used to assess the thermal comfort in terms of physiological mechanism. In addition, the neutral temperature was 24.7 °C and the upper limit for 80% acceptability was 28.2 °C in SET*. Full article

There exists huge differences in climatic conditions and occupant energy-consuming behavior between Berlin and the “hot summer and cold winter zone of China” (HSCW), which implies that the building energy consumption compositions of two regions are completely different. In this paper, dynamic energy consumption simulation for passive houses with Design Builder software was performed. The results indicated that the improvement of building airtightness and exterior wall insulation can reduce annual heating and cooling load effectively, and more importantly the effect is much stronger on heating load than cooling load. Because of this, the paper proposed that the ratio of heating and cooling electricity consumption (r) should be adopted as an important index in energy efficiency evaluation of passive houses. It would contribute to the reasonable selection of ventilation modes and the exterior wall heat transfer coefficient, and benefit the healthy development of passive houses in HSCW. Full article