Winter Zone Research Articles

A systematic review on thermal environment and thermal comfort studies in Chinese residential buildings

Amid the backdrop of the energy crisis, thermal comfort is crucial to achieve energy savings. Residential buildings are characterized by a wide range of adaptive comfort opportunities. However, there has been a lack of systematic refinement and review of residential thermal comfort field studies in China to provide valuable recommendations for energy conservation. We systematically reviewed studies on thermal environment and thermal comfort in Chinese residential buildings published in peer-reviewed journals up to 2020. A total of 34 studies were deemed to have provided sufficient information on both the thermal environment and thermal comfort. We found that in winter, there were obvious differences between urban and rural dwellings in Severe Cold (SC) and Cold (C) zones, with regard to their indoor air temperature (urban: 19.8 ∼ 25.0 °C v.s. rural: 11.3 ∼ 17.8 °C) and neutral temperature (urban: 17.6 ∼ 25.1 °C v.s. rural: 11.9 ∼ 23.45 °C). While in summer, the indoor air temperature in urban dwellings were slightly lower than those in rural areas due to their prevalent use of air conditioner (urban: 26.1 ∼ 28.9 °C v.s. rural: 29.5 ∼ 34.9 °C). Indoor air temperature and neutral temperature varied considerably in different climate zones in winter. In SC zones, the indoor environment was overheated, which could lead to energy wastage and overheating discomfort for residents. Residents in Hot-Summer and Cold-Winter (HSCW) zone were the most tolerant to the variation of thermal environment (the median coefficient of MTS or TSV equation: SC: 0.18; C: 0.20; HSCW: 0.13; HSWW: 0.23).

A macro-scale optimisation of zero-energy design schemes for residential buildings based on building archetypes

Energy conservation and carbon emission reduction in the building sector have become a global concern in combating environmental issues. To achieve this target, developing low-energy buildings becomes an integral approach. Different from the case-by-case design for public buildings, the geometrical construction form of residential buildings are roughly the same and can be concluded in several representative categories, which leads to several similar paths to achieve energy-saving targets for buildings belonging to the same category. Aiming to determine the applicable design schemes for each archetypal building, the architectural typology method and simulation-based method were used in this research. Furthermore, an optimisation step was done the design schemes from both energy and economic perspectives. As demonstrated in Ningbo city as a case, this research usesthe number of floors, building shape coefficients, average floor areas, and window-to-wall ratiosas classification factors based on previous research and proposed nine representative building archetypes. Subsequently, 512 (29) groups of design schemes combined from nine energy-saving measures were simulated for each building archetype. Considering the energy performance indexes as anenergy-perspective constraintand the life-cycle cost of design scheme as aneconomic-perspective constraint, the design scheme was optimised. The limitation of this research is the neglect of immediate environment such as proximity to other buildings or natural elements such as trees that provided a subsequent research direction. Specifically, this research obtained optimal design schemes of energy-saving targets for individual residential building archetypes in China’s hot summer and cold winter zone. Broadly, this research proposed a comprehensive method for individual building assessment and optimisation that could be further used for a urban-scale energy planning and prediction.

Research on Envelope Thermal Performance of Ultra-Low Energy Rural Residential Buildings in China

Rural energy consumption plays an important role in energy consumption due to the improvement of rural residents’ living quality requirements in China. Ultra-low energy rural residential buildings are proposed to decrease rural energy consumption. First of all, this paper aims to provide the definition of ultra-low energy rural residential buildings, which is to reduce 50% of the building energy consumption of the rural residential benchmark building according to the Chinese standard for energy efficiency of rural residential buildings. Secondly, this paper presents the heat transfer coefficients of building envelopes of ultra-low energy rural residential buildings in the severe cold zone, cold zone and hot summer and cold winter zone in China. Based on optimized design and simulation analysis, the heat transfer coefficients of building envelopes are determined by the construction cost, energy efficiency and retrofit feasibility. Thirdly, the suitable combination of a high-performance external wall and internal wall is recommended based on carbon emission and cost efficiency. As an achievement, a technical specification for ultra-low energy rural buildings has been proposed by the China Academy of Building Research. It is beneficial to design ultra-low energy rural residential buildings in China and other countries.

Hygrothermal performance of a self-insulated exterior wall with various exterior/interior insulation thicknesses in two climate zones in China: A novel moisture-energy-environment-economic (M3E) method in insulation thickness optimization

The accumulation of moisture inside the envelope under high-humid climates can strongly affect the hygrothermal properties and can lead to moisture-related damage / moulds to the materials, especially in severe weather conditions. However, the optimal insulation thickness of the exterior envelope is typically determined by factors such as overall heat transfer performance, carbon dioxide production and economic cost. The effect of insulation thickness on the annual average moisture content (AAMC) of a self-insulated exterior envelope is often neglected and seldom considered in the optimization process. In this study, a coupled heat, air and moisture transfer (HAM) model was derived and validated. Theoretical indices for water vapour transfer were implemented, such as moisture storage coefficient and moisture inertia factor. A simplified model for liquid water penetration and evaporation was also implemented. A novel four-dimensional moisture-energy-environment-economic (M3E) method that incorporates moisture content analysis was proposed for insulation thickness optimization. A case study was conducted on a self-insulated aerated concrete wall in two climate zones: the hot summer and cold winter (HSCW) zone and the cold zone. The insulation thickness interval investigated were 0–50 mm for interior thermal insulation (ITI) and 0–60 mm for exterior thermal insulation (ETI). The results of the case study showed that the AAMC of the entire envelope varied up to 15.2% (HSCW zone) and 10.0% (cold zone) for different insulation thicknesses. In the HSCW zone, the lowest AAMC of the outer part of the envelope adjacent to the atmosphere was found at 30 mm (ITI) or 20 mm (ETI), indicating the presence of turning thicknesses; while in the cold zones, the lowest AAMC was found at 50 mm (ITI) or 10 mm (ETI) with no turning thickness. The proposed theoretical implementations accounted for changes of AAMC in different interior/exterior insulation thicknesses and were verified with the results of numerical calculation. The proposed theoretical indices revealed an opposite effect of water vapour transfer and liquid water transfer on the AAMC for different insulation thicknesses, which can explain the presence of turning thickness. Furthermore, the selected optimal insulation thicknesses from Pareto fronts were found around 25–29 mm for ITI and 36–38 mm for ETI in two climate zones. The results from the M3E method showed a reduction in moisture risks (up to 62.91%) and mould growth risks (up to 4.84%) in the case study, successfully meeting the acceptable range of moisture risk and mould growth risk. The findings of this paper can help generate a new understanding of moisture transfer, and the proposed M3E method can be applied in all cases to reduce the moisture/mould growth risks in the design stage.

Daylight-electrical-thermal coupling model for real-time zero-energy potential analysis of vacuum-photovoltaic glazing

Windows are considered as the main culprit of heat loss in buildings and the development of advanced glazing is a global necessity. Vacuum integrated photovoltaic (VPV) glazing was proven to have great air conditioning energy-saving potential, while there is a lack of real-time zero-energy potential evaluation that considers the interaction between thermal, power and daylight performances. Given this context, a daylight-electrical-thermal coupling model was developed using Python language for VPV glazing to evaluate its overall performance for optimal design towards real-time zero-energy goal. The coupling model integrated the numerical heat transfer model, electrical model, as well as decision tree and random forest algorithms for glare and illuminance prediction. All models were validated through full-scale outdoor experiments and showed acceptable errors between experimental and simulated data. Based on that, key parameters affecting the performance of the VPV glazing, namely PV coverage, emissivity of Low-E coating, pillar separation, and inner window shades were determined through sensitivity analysis. A case study of optimal design of the VPV glazing in hot summer and cold winter zone in China showed that VPV glazing with a PV coverage of 40%, a coating emissivity of 0.068, and a pillar separation of 90 mm can achieve 67% zero-energy hours throughout the year. This study can provide a validated coupled model for performance evaluation and optimization of VPV glazing for engineering applications.

Parvovirus B19 in Morocco: Seroprevalence of Immunoglobulin G Antibody in Pregnant Women in Marrakesh

Background: Parvovirus B19 (B19V) infection is ever-present and contagious. It is acquired during childhood and adolescence, but can occur at any age. B19V infection occurs in endemic epidemic mode in temperate zones in winter and spring. B19V infections, although often asymptomatic in pregnant women, can be responsible for hydrop fetalis, fetal anemia, and death in utero. This study will evaluate the seroprevalence of immunoglobulin G (IgG) antiparvovirus in pregnant women in Marrakesh city in Morocco, and to find out the possible risk factors associated with B19V infections. Methods: We randomly selected 100 pregnant women from the Zerktouni hospital in Marrakesh. Socio-demographic characteristics and background were collected using a questionnaire. Serologic tests were carried out by searching for immunoglobulin G antibodies via the ParvovirusVirclia® IgG Chemiluminescencemonotest kits (Vircell Microbiologist, Granada, Spain) at the Bacteriology-Virology laboratory of the Avicenna Military Hospital in Marrakesh. Results: The median age of study participants was 27 (interquartile range (IQR): 17–43) years. Of 100 pregnant women 8%, 38% and 54% were in the first, second and third trimester respectively. The majority 96% of women were from urban areas. Nineteen percent (19%) of them had a history of spontaneous abortion. Of 100 pregnant women, the overall prevalence of IgG was 51 (51%). The average age of participants with positive serology was 26.45 years, and the mean age of those with negative serology was 28.98 years. The immunity against the virus was higher in young pregnant women. Twenty five (25%) women tested positive for B19V antibodies in the third trimester of pregnancy, implying immunity for the virus. The results of logistic regression showed insignificant association between the prevalence of B19V IgG antibodies and the demographic and obstetrical factors except for the having a child under 6 years factor (χ2 = 12.33, p = 0.001). Conclusions: Infection with B19V remains important in pregnant women in our region and virological diagnosis must be sought before any suggestive context.

Using Real Building Energy Use Data to Explain the Energy Performance Gap of Energy-Efficient Residential Buildings: A Case Study from the Hot Summer and Cold Winter Zone in China

The International Energy Agency (IEA) emphasizes that using real building energy use data (RBEUD) to reflect the actual condition of buildings and inform policy-making is the most effective way to reduce buildings’ carbon emissions. However, based on IEA’s evaluation, regional and national building stock data are limited and lacking. Especially for China, the lack of RBEUD in buildings has limited our ability to address the energy performance gap (EPG). In this research, EPG refers to the difference between regulated energy consumption by design standards and actual energy usage. EPG makes it difficult to develop buildings that are energy-efficient. Therefore, this study aims to gather and analyze RBEUD in order to understand the role of occupants’ behavior in explaining the EPG of energy-efficient residential buildings in China. The results suggest that the actual consumption of residential buildings is less than 1/5–1/3 of the theoretical limits. The heat pump and air conditioner’s actual schedules and setpoint settings are the significant drivers that explain the EPG. In addition, the presentation of a database of 1128 households provides actual usage behavior parameters for policy-makers to improve the accuracy of building energy forecasting models.

Application potential analysis of different control strategies for radiant floor cooling systems in office buildings in different climate zones of China

The application potential of radiant floor cooling systems is affected by climatic conditions. The meteorological parameters of 22 cities in five climatic zones in China (severe cold (SC), cold, hot summer and cold winter (HSCW), hot summer and warm winter (HSWW), and temperate) are analyzed to evaluate the applicability of four conventional control strategies of radiant floor cooling system in office buildings. The control strategies are modeled in the Transient System Simulation Program (TRNSYS), and the indoor thermal comfort, condensation risk, energy consumption, and carbon emissions are analyzed. Multi criteria decision-making is used to evaluate the radiant floor system. The results show that the control strategy with direct ground cooling produces the highest energy savings in the five climate zones. The energy savings are 25–66 % higher than those of the three control strategies using a heat pump as a cold source. Under the same indoor environment conditions, the three-step control strategy provides the optimum indoor temperature and humidity control. The number of hours when the three-step control strategy exceeds the thermal comfort zone is 5 % in 22 cities, and the number of hours with condensation risk is only 3%. The variable water supply temperature control and precooling control have better performance than the other strategies in the SC, cold, and temperate zones. In addition, the control strategies are ranked based on their application potential in 22 cities. The application potential of the radiant floor cooling system with a direct ground cooling source is the highest in the five climate zones in the two scenarios with equal weights of the four criteria and is preferable due to less carbon emissions. When the condensation risk is considered, the radiant floor cooling system with a direct ground cooling source exhibits better performance in the SC and cold zones. The variable water supply temperature control is the optimum strategy in the HSCW, HSWW, and temperate zones. The precooling control strategy ranks the highest in Changchun and Guiyang, and the three-step control strategy performs the best in Shanghai.

Feasibility study on solar coupled gas-fired boiler heating system retrofit in residential buildings in the HSCW zone of China

Residential buildings in the hot summer and cold winter (HSCW) zone rely on gas-fired boiler for heating have a certain application basis, but high operating costs and limited gas consumption seriously limit the promotion of gas-fired boiler. To reduce domestic gas consumption in Wuhan, two solar auxiliary gas-fired boiler heating systems formed in parallel and series are proposed and explore the feasibility of coupled heating system retrofit. The simulation models of two solar coupled gas-fired boiler heating systems are established by TRNSYS, and the results indicate that the indoor thermal environment of the two systems is good and the temperature of the tank is stable. The solar fraction of the parallel system reaches 24.40%, which has better energy saving. The optimization analyses display that the system has the best economy when the collector area ratio is 10.0%, and the collector area and tank volume ratio is 8/0.7. The solar-assisted parallel heating system retrofit can save 2.02 × 104 MJ over the entire life cycle, and the increased initial investment can be recovered within 4.75 years. The research results can provide a basis and new ideas for the heating retrofit of the gas-fired boiler in residential buildings in the HSCW zone.

Research on Energy-Saving Performance of Intermittent Heating for Rooms in Hot Summer & Cold Winter Zone

Research on Energy-Saving Performance of Intermittent Heating for Rooms in Hot Summer & Cold Winter Zone

Analysis of temperature regulation and heat storage effect of the combined phase change envelope in hot summer and cold winter zone

In order to study the character of heat storage and temperature regulation, a mathematical model of the thermal performance of an ideal passive energy storage building is established. Indoor thermal environment evaluation indexes of the passive buildings such as the temperature attenuation coefficient and supercooling degree/superheating degree are proposed. The PCM (phase change materials) layer numbers, the total thickness and the thickness ratio of PCM layers of the combined PCM envelope are analyzed based on the simulation. The result shows that the combined envelope with two-layer PCM has better temperature regulation and heat storage effect. When the total thickness of the combined PCM envelope is 40 mm, and the thickness ratio of the PCM layer from the inside to the outside is13.3:26.7, the annual thermal comfort hours are the longest.

Climate Adaptability Analysis on the Shape of Outpatient Buildings for Different Climate Zones in China Based on Low-Energy Target

Under the impact of COVID-19 and the needs for urban expansion, a large number of outpatient buildings have been rapidly constructed, but the problem of high energy consumption has always been ignored. There is a lack of research on the adaptability of building shape in different climate zones. Many studies have shown that a reasonable shape in the early stage of design can significantly reduce the energy consumption of buildings. Therefore, it helps if architects quickly select a reasonable shape that can effectively reduce energy consumption. This study summarized a number of outpatient building cases in China and proposed three typical building shapes: centralized-type (Shape-1), corridor-type (Shape-2), and courtyard-type (Shape-3). The Design Builder tool was used to simulate and analyze the typical building energy consumption in different climate zones. The simulation results show that Shape-2 (angle: 0°) should be chosen in severe cold zone; Shape-1 (angle: 90°) should be chosen in cold zone; Shape-1 (angle: 0°) should be chosen in hot summer and cold winter zone; Shape-1 (angle: 60°) should be chosen in hot summer and warm winter zone; and Shape-1 or Shape-2 can be chosen in warm zone. The results of this study can provide suggestions for the energy saving design of outpatient buildings in China and other areas with similar conditions. The result can help architects make rapid shape selection in the early stage of design.

Study on outdoor thermal comfort of factory areas during winter in hot summer and cold winter zone of China

The factory area is an important part of the city. Its environment is relatively simple, mainly with large plant buildings and less vegetation, which is easy to form an extreme outdoor thermal environment. However, few studies have focused on how these changes affect outdoor thermal comfort in factory areas. In this study, through field meteorological measurements and questionnaire surveys, outdoor thermal comfort of different built environments in two factory areas in Haining, China, located in the hot summer and cold winter zone, was studied in winter. Combined with thermal comfort indices Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI), 12 observation sites in factory areas were analyzed to establish the outdoor thermal benchmark suitable for the factory area. The results show that: (1) Thermal comfort was strongly related to thermal sensation. (2) Air temperature and globe temperature were two primary factors affecting workers' thermal sensations. In addition, thermal sensation was negatively correlated with wind speed and relative humidity. (3) The built environment had a significant influence on human thermal sensation and thermal comfort; sky view factor was an important morphology parameter that affected outdoor thermal sensation, and the outdoor thermal sensation improved as it increases. (4) Neutral temperatures of PET and UTCI were 14.3 °C and 15.8 °C; neutral PET range and neutral UTCI range were 10.7–17.8 °C and 12.2–19.4 °C, respectively. These findings could serve as theoretical baselines and guidelines for factory area design.

Residential indoor thermal environment investigation and analysis on energy saving of air conditioning in hot summer and warm winter zone in China

The increasing sharply penetration of air conditioning causes a large number of energy consumption, it is crucial to identify a solution to reduce energy consumption. In this study, the operation pattern of air conditioning (A/C), indoor thermal environment, residents' thermal comfort and energy consumption in multi-residential buildings in hot summer and warm winter zone are analyzed by means of field measurements and questionnaire surveys. Most observed indoor temperature fell within the range of 28–30 °C. Because the relative humidity reached up to more than 90%, some residential indoor thermal environment has the risk of heatstroke. It can be obtained 28.4 °C as the thermal neutral temperature, and the acceptable temperature ranges from 27.1 °C to 29.6 °C, which is much higher than other climate zones. Moreover, the simulation software Energy-Plus was used to simulate and verify the energy consumption of typical multi-residential buildings. Simulation results indicate that each 1 °C increase of setting temperature would lead to an approximately 20% reduction in cooling energy consumption. The appropriate setting temperature of air conditioning is the temperature which could achieve the actual indoor temperature maintain at approximately 28–29 °C, the appropriate service time and switching behavior of A/C also have positive effect on the reduction of energy consumption.

The method of reducing heat loss from thermal bridges in residential buildings with internal insulation in the hot summer and cold winter zone of China

The higher demands for energy efficiency in nearly zero energy buildings (nZEBs) give rise to concerns on the impact of thermal bridges on building's thermal performance. The extra heat loss by thermal bridges needs to be reduced especially for residential nZEBs with internal insulation in China's Hot Summer–Cold Winter (HSCW) zone. This paper defines and compared four typical types of thermal bridges based on their constructional and thermal characteristics. A novel multi-objective optimization method for determining the best construction to improve thermal bridges is also proposed. The heat loss through thermal bridges was estimated through the linear thermal transmittance using COMSOL Multiphysics software. Optimization of design parameters was carried out by Pareto-based multi-objective optimization tool in Python, while heat loss reductions and quantities of material have been comprehensively considered. Corresponding suggested values for design parameters of each thermal bridge type have been put forward. Results obtained by a case study of a typical residential nZEB under various thermal bridge conditions and different air-conditioning patterns also highlight the importance of insulation design of envelope considering the influence of thermal bridge, where the proportion that on annual heating and cooling loads can be reduced from 1.7%-8.2% to 0.4%–2.5%. • Definition and comparation of thermal bridges' impacts on heat loss. • Proposed thermal bridge improvement methods for each type of junction. • Multi-objective optimization for both energy efficiency and material saving. • Energy performance in a residential nZEB considering effects of thermal bridges.

Reducing Energy Consumption and Improving Comfort by Retrofitting Residential Buildings in the Hot Summer and Cold Winter Zone of China

Reducing Energy Consumption and Improving Comfort by Retrofitting Residential Buildings in the Hot Summer and Cold Winter Zone of China

The characteristics of microorganisms in residence in summer and winter among different climate zones, China

<p indent="0mm">Indoor microbes have been listed in the category of indoor air pollutants by World Health Organization (WHO) in 1990. Exposure to a high concentration of airborne bioaerosol potentially causes adverse health effects, such as pneumonia, asthma, and allergies. People spend most of their time in residence in their life, so figuring out the characteristic of residential airborne microbes is very important for occupants’ health. However, previous studies mostly focused on indoor microorganisms in public buildings, while very little work has been done on the characteristics of indoor airborne bacteria and fungi in residence. In this study, we investigated the indoor airborne bacterial concentration, fungal concentration, and taxonomic diversity of residences in summer and winter among five different climate zones across China, as well as the community structure, and revealed the correlations between indoor airborne microbial characteristics (concentrations and taxonomic diversity) and geographical location by using polynomial fitting. Culturing and sequencing methods were combined in this study, for which we collected 376 culturable samples and 168 sequencing samples of bacteria and fungi each. We found the bacterial concentrations between summer and winter were significantly different in the hot summer &amp; cold winter climate zone and the hot summer &amp; warm winter climate zone, whereas there was no significant difference between different seasons among different climate zones for fungal concentrations. The bacterial concentrations in the hot summer &amp; cold winter zone (Nanjing, 875±553 CFU/m³) and hot summer &amp; warm winter (Shenzhen, 758±473 CFU/m³) were significantly higher than those in the other climate zones in summer (<italic>P </italic>&lt; 0.05); the lowest bacterial concentrations in winter were found in hot summer &amp; cold winter (Nanjing, 191±119 CFU/m³). For fungi, the highest concentrations were found in the severe cold climate zone (Harbin, 743±798 CFU/m³) and cold climate zone (Lhasa, 1369±1380 CFU/m³) in summer; while the highest was only found in the severe cold climate zone (Harbin, 654±493 CFU/m³) in winter. We also found that the bacterial diversity in the hot summer &amp; cold winter climate zone was significantly different between summer and winter; the fungi diversity in the hot summer &amp; cold winter climate zone and hot summer &amp; warm winter climate zones was significantly different between summer and winter. For bacteria, the lowest taxonomic diversity in summer was found in severe cold climate zone and the highest was found in hot summer &amp; cold winter climate zone; the lowest taxonomic diversity in winter was found in severe cold climate zone and hot summer &amp; cold winter climate zone. For fungi taxonomic diversity, the highest values were found in severe cold climate zone and hot summer &amp; cold winter climate zone in summer; the highest values were found in cold climate zone and hot summer &amp; warm winter climate zone in winter. We analyzed the community structure of bacteria and fungi at the phylum level. The TOP 4 bacterial species and TOP 3 fungal species between different climate zones in summer and winter were similar. The TOP 4 bacteria species in residences were <italic>Bacteroidetes</italic>, <italic>Proteobacteria</italic>, <italic>Firmicutes</italic>,<italic> </italic>and <italic>Actinobacteria</italic>. The TOP 3 fungi species were <italic>Ascomycota</italic>, <italic>Basidiomycota</italic>, and <italic>Zygomycota</italic>, except for Beijing, which is located in a cold climate zone. By analyzing the correlations between indoor microbial characteristics and geographical location, we found the variation of indoor microbial diversity with latitude was opposite in summer and winter. In summer, indoor bacterial concentrations and diversity first increased and then decreased with the increase of longitude, which was opposite to the trend of fungi. There was no correlation between winter bacterial concentrations and geographical location.

Comparison of airborne bacteria and fungi in different built environments in selected cities in five climate zones of China

Bioaerosols in different built environments and climate zones have unique effects on occupant health, which demands comparisons of their characteristics to make targeted control measures. This study investigated bioaerosol distribution in five different climate zones across China with four building types (n = 686 rooms). The results showed significant disparities in bioaerosol concentrations among various buildings and climate zones. The bacterial concentrations in residences (536 ± 647 CFU/m3) were significantly higher than in schools, offices, and hospitals owing to different built environments and human activities. The highest mean value of fungal concentration was found in schools (826 ± 955 CFU/m3) due to their greater landscaping area. The bacterial concentrations in the cold zone (307 ± 506 CFU/m3) and the hot summer and cold winter zone (214 ± 180 CFU/m3) were significantly lower than in the other three climate zones. The fungal concentrations in the severe cold zone (709 ± 900 CFU/m3) and the hot summer and warm winter zone (1094 ± 832 CFU/m3) were significantly higher than in the other three climate zones; the lower the indoor temperature (T) and the higher the air exchange rate, the lower the indoor airborne bacterial concentration; the lower the relative humidity (RH), the lower the indoor airborne fungi. In addition, a higher air exchange rate could also reduce the effect of occupant density on indoor bacterial concentration. The results of this study provide valuable data on bioaerosol profiles in various built environments and climate zones and highlight the significance of T, RH, and air exchange rate on indoor bioaerosol concentrations.

Optimal design of complex dynamic shadings: Towards sustainable built environment

Complex dynamic shading is one of many innovative technologies widely used to improve comfort and energy saving for the construction of a sustainable built environment for modern cities. However, the dynamic mechanism of the complex shading design has not always been well understood, which plays significant importance in the building performance of cities especially considering the complex environmental conditions. In this study, we aim to optimize the annual daylighting and energy performance of a complex, dynamic, origami-based shading system based case studies of a typical city building, which is located in the hot summer and cold winter (HSCW) zone in China. A modified parametric behavior maps (PBM) method was utilized for performance evaluation. A multivariate function was used to describe the interaction between the annual operation schedule and three environmental stimuli, i.e., hourly solar radiation reaching the south-facing window, hourly mean illuminance of the room, and hourly outdoor dry-bulb temperature. Radiance and EnergyPlus were integrated into the annual performance simulation of the dynamic shading. Experimental data has been used for validation of the dynamic strategy. The results indicated that the performance of the complex dynamic shading compared to the conventional static overhang shading depends largely on the annual operation schedule on an hourly basis. Indeed, the dynamic behaviors of complex shadings can improve the daylighting performance by 91.5% and energy performance by 19.9%, respectively, for office buildings with a large window-to-wall ratio in China's HSCW zone. This study will contribute to the performance-based design of complex dynamic shading, and further help to improve sustainability in urban design for modern cities.

Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Recycling the condensate water of the air conditioner could be explored as an alternative water source to contribute to building the green campus. This paper explored the condensate water production through actual measurement based on a split air handling unit (SAHU) in a university building. Then, the statistical analysis was used to analyze the recycling feasibility and the impact factors of the condensate water production in 31 Chinese provincial capital cities to obtain the recycling potential map of the condensate water generated from a SAHU. Results showed that: (1) In the measurement, the amount of condensate water produced by a single split air conditioner was 1.6 kg from 12:40 to 13:40. Therefore, the daily output of condensate water of the air conditioner with the university operation schedule could reach 52.99 kg during the main air-conditioning season. (2) Among the 31 provincial capital cities in China, the largest condensate water outputs could be found in the Hot Summer and Warm Winter zone and the Hot Summer and Cold Winter zone, with an average monthly output of 1600 kg and 1100 kg, respectively. (3) Regression analysis showed that the dry-bulb temperature and dew point temperature of outdoor air had the highest positive and significant influence on condensate water production. The objective of this study is to provide theoretical guidance for the design and energy conservation evaluation of the feasibility of SAHU condensate water recycling in universities.