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There have been fruitful publications on thermal comfort of urban residential buildings in China. However, there is a lack of reviews on this topic to perform a comprehensive analysis and find opportunities to meet occupants' thermal comfort needs while improving building energy efficiencies. This paper addresses this issue by presenting a systematic review on the advancements in research on thermal comfort in urban residential buildings in China. Firstly, two common thermal comfort research approaches, i.e., field studies and laboratory studies, are discussed. Secondly, eleven main thermal comfort evaluation indicators are summarized. Finally, this paper analyzes the thermal comfort survey data from different researchers, discusses the impacts of adaptive behaviors on human thermal comfort, and provides recommendations for future research on urban residential thermal comfort. It was found that people have higher and higher requirements for their indoor thermal environment as time goes by, especially in the winter; the thermoneutral temperature is higher in warmer climate regions in the summer but lower in the winter than in colder climate regions; the thermoneutral temperature tends to increase with the indoor air temperature due to an adaptation to the indoor thermal environment. The outcomes of this paper provide valuable information on thermal comfort behaviors of urban residents in different climate zones in China, which can serve as a resource for the academic community conducting future research on thermal comfort and assist policymakers in enhancing building energy efficiencies without compromising the occupants' comfort. [ABSTRACT FROM AUTHOR]

Outdoor environment exchanges heat with indoor environment, enabling pollutants to infiltrate indoors, affecting buildings' energy efficiency, comfort, and indoor air quality. Investigating the impact of the outdoor environment on the indoor thermal environment is crucial. Firstly, this paper reviews the coupling method to link the outdoor environment with the indoor environment. Secondly, it examines the impact of the outdoor physical environment, including neighboring buildings, greening, road surface, water body, and sky, on the indoor thermal environment. During the hottest summer, an increase of 17% in trees can reduce indoor temperature by 1.1 °C. Thirdly, the impact of weather conditions, including outdoor temperature, outdoor humidity, external wind, global warming, extreme weather conditions, and solar radiation, on the indoor thermal environment is studied. Due to global warming, cooling energy consumption and heating energy consumption in 2050 could increase by 223% to 1050%, and heating demand could decrease by 36% to 58%. Finally, the impact of outdoor air pollution on indoor environment and energy consumption is analyzed. For every 75 μg/m3 increase in PM2.5 concentration, average power consumption could increase by 11.2%. Recommendations for future research are provided. This study contributes to the understanding of the outdoor–indoor thermal relationship and offers insights into enhancing indoor thermal comfort and reducing building energy consumption. [ABSTRACT FROM AUTHOR]

Buildings consume about 40% of the global energy. Therefore, the building sector plays a key role in achieving the goals of carbon peak and carbon neutrality. Various energy-saving technologies for buildings, such as building envelops, mechanical systems, and energy resources, have been developed to help to achieve zero- or even net-energy buildings while maintaining comfort and a healthy indoor environment. This Special Issue on building energy-saving technology was open to all contributors in the field of building engineering. The original experimental studies, numerical simulations, and reviews in all aspects of building energy utilization, management, and optimization have been considered. For this event, all of these topics were covered in the extensive submissions which were accepted, but interesting papers on other aspects of building energy efficiency were also received. The purpose of this editorial is to summarize the main research findings of the accepted papers in this Special Issue, including the energy-saving technologies involved in building envelops, mechanical systems, and occupant behaviors, and to identify a number of research questions and research directions. [ABSTRACT FROM AUTHOR]

Sleep is vital for human health, while sleep quality is affected by indoor thermal environments. This study aims to investigate human thermal comfort with a thermal-conductive bed during sleep in summer. A series of experiments were conducted in a climatic chamber of a university. Subjects slept on a thermal-conductive bed, with or without the supply of water cooling them by flowing through the pipes embedded in the bed. The supply water was set at 20, 25, 28, and 30 °C. The indoor temperature was set at 32 °C. The bed surface temperature (back, buttock, thigh, and calf) and the subject's skin temperature were measured. Questionnaires after waking up the next morning were conducted. The results show that when there was no water supply in the pipes of the thermal-conductive bed, the bed surface temperature was 0–1.5 °C higher than the indoor temperature, and subjects felt slightly warm. When the supply water temperature was 28 or 30 °C, subjects felt thermally comfortable during a night's sleep. This study demonstrates that the proposed thermal-conductive bed with supply water temperatures of 28–30 °C can create a comfortable sleep environment for residents who have no air-conditioning systems in summer, which can also help save building energy. [ABSTRACT FROM AUTHOR]

The building sector accounts for over 40% of global energy consumption. The utilization of renewable energy systems such as the solar-assisted heat pump (SAHP) in buildings has been shown to improve building energy efficiency and achieve carbon neutrality. This paper presents a review of the research and development of solar-assisted heat pumps for buildings in China. It firstly introduces the different stages of solar-assisted heat pump research. Secondly, the research on different types of heat pumps, the core components of heat pumps, the computer software used, and the economic feasibility evaluation of solar-assisted heat pumps are presented. Thirdly, the application of SAHPs in practical projects is examined and relevant regulations, standards, and policies for solar-assisted heat pump development in China are highlighted. Finally, recommendations for the future development of solar-assisted heat pumps in China are suggested. [ABSTRACT FROM AUTHOR]

The impacts of greenery systems (GSs) on microclimate conditions and building energy performance have been frequently investigated using experiments and simulations during the past decades, especially in summer and winter. However, few studies have focused on the performance of GSs in transition seasons. The ambient weather conditions vary with great fluctuations during transition seasons, which may result in severe oscillations in indoor environments. To investigate the impacts of GSs on indoor environments, an experiment was conducted using a contrastive test platform, which consisted of two experimental rooms, one equipped with a GS and the other without, from 1 April 2019 to 31 May 2019 in Hunan, China. Both rooms were free-running. The experimental results showed that the GS had the ability to reduce the oscillations in the indoor environment. The oscillations in indoor dry-bulb temperature (DBT) and relative humidity (RH) were reduced by 39.3% and 28.8%, respectively. The maximum daily DBT and RH ranges were, respectively, cut down by 3.5 °C and 12.4%. The maximum reductions in external and internal surface temperatures were 29.5 °C and 9.4 °C, respectively, for the GS, while the average reductions were 1.6~4.1 °C and 0.2~1.3 °C, respectively, depending on the orientation of the surfaces. The operative temperature (OT) during the daytime on sunny days was also lowered by the GS. The differences in OT between the two rooms ranged from −1.8 °C to 8.2 °C, with an average of 1.0 °C. The GS can improve the indoor thermal comfort during transition seasons. The thermal dissatisfaction was decreased by 7.9%. This lengthened the thermal comfort time by 15% across the whole day and by 28% during the daytime. This indicates reductions in air-conditioning system operating times, leading to energy savings. [ABSTRACT FROM AUTHOR]

Healthy buildings are a deep-level development of green buildings, which can effectively help relieve stress and improve occupants' physical and mental health. In addition, they are is likely to play an important role in preventing the spread of respiratory infectious diseases. Therefore, healthy buildings have attracted worldwide attention. This article reviews the research and development of healthy buildings in China. First, it briefly introduces the definition of healthy buildings, the key elements of evaluation standards, energy conservation measures and new technology applications for healthy buildings, and lessons learned from the global outbreak of SARS-CoV-2. Secondly, it presents the milestones of healthy building development and healthy building projects in China, and the benefits of healthy buildings were also discussed. Finally, the differences in the evaluation systems of healthy buildings between China and other countries were analyzed, the problems of the current policy system of healthy buildings in China were identified, and suggestions for future development were provided. [ABSTRACT FROM AUTHOR]

Liquid entrainment in a flooded evaporator has an important impact on the performance and safety of a water-cooled centrifugal chiller. In this paper, two methods for measuring the liquid entrainment factor in the evaporator of a centrifugal chiller based on energy balance are proposed. Method 1 involves only the heat exchange capacity of the evaporator and Method 2 involves both evaporator and condenser. The applicable conditions of the methods are discussed. Experimental measurements on the flooded evaporator of a single-stage water-cooled centrifugal chiller with refrigerant R134a show that, for a system with good thermal balance, there is little difference in the entrainment factor values obtained by the two methods. Method 2 was found to have slightly higher measurement accuracy, compared to Method 1. The uncertainty propagation analysis shows that for Method 2, the inlet and outlet water temperatures of the evaporator and condenser, motor input power, motor efficiency, transmission power loss and compressor suction and discharge temperatures are important factors. The experimental results show that the variation of the evaporator entrainment factor with refrigerant charge amount is different for different cooling capacity. At 700 and 800 refrigeration ton (RT), the entrainment factor of the test evaporator increases with the increase of refrigerant charge and the growth rate gradually accelerates. For the chiller tested, when the entrainment factor reaches 0.89% and 1.02%, respectively, at 700 ton and 800 ton, the rapid increase of the entrainment factor leads to a significant decrease in the coefficient of performance (COP) during the charging process. Based on the analysis of the experimental results, it is recommended that the maximum entrainment factor for efficient operation of the centrifugal chiller should be controlled within 1%. [ABSTRACT FROM AUTHOR]

Vacuum freeze-dryer has been widely used in many fields such as food, medicine, and beverage. In the actual operation process, the freeze-dryer and factory buildings need to consume a lot of cold energy. In order to reduce energy consumption, this paper presents a freeze-dryer system using solar energy absorption refrigeration in conjunction with buildings. Through the solar absorption refrigeration system, the cooling capacity is supplied to the freeze-dryer and the building at the same time, so that the cold can be cascaded utilization. The simulation of the system by TRNSYS software shows that the system can greatly reduce the consumption of conventional energy, and it is a new energy-saving measure of vacuum freeze-dryer and building air conditioning. [ABSTRACT FROM AUTHOR]

A climate-responsive landscape design can create a more livable urban microclimate with adequate human comfortability. This paper aims to quantitatively investigate the effects of landscape design elements of pavement materials, greenery, and water bodies on urban microclimate and thermal comfort in a high-rise residential area in the tropic climate of Singapore. A comprehensive field measurement is undertaken to obtain real data on microclimate parameters for calibration of the microclimate-modeling software ENVI-met 4.0. With the calibrated ENVI-met, seven urban landscape scenarios are simulated and their effects on thermal comfort as measured by physiologically equivalent temperature (PET) are evaluated. It is found that the maximum improvement of PET reduction with suggested landscape designs is about 12°C, and high-albedo pavement materials and water bodies are not effective in reducing heat stress in hot and humid climate conditions. The combination of shade trees over grass is the most effective landscape strategy for cooling the microclimate. The findings from the paper can equip urban designers with knowledge and techniques to mitigate urban heat stress. [ABSTRACT FROM AUTHOR]

With the widespread application of graphene oxide (GO), it would be inevitably released into wastewater treatment plants (WWTPs) and get involved in the biochemical process. So far, there are controversies on the effects of low GO concentration (0.05–0.1 g/L) on the nitrogen removal process. Therefore, this study essentially investigates any potential effects of GO on wastewater microbial communities functions. In present study, the nitrifying and denitrifying batch tests were introduced to investigate the influence of 0.06 g/L of GO on bacteria. The results showed that GO could be easily combined with the aerobic granular sludge (AGS), and NH 4 + -N was sharply absorbed, which directly promoted the bioactivities of ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) and extracellular polymeric substances (EPS) production. The influence of GO on the denitrifying bacteria was negligible, which resulted in the stable EPS production. Furthermore, as inferred from the near maximum chemical reaction rates, there were no obvious changes on the microbial community functions during nitrogen removal process. [ABSTRACT FROM AUTHOR]

This paper presents the optimization of building envelope design to minimize thermal load and improve thermal comfort for a two-star green building inWuhan, China. The thermal load of the building before optimization is 36% lower than a typical energy-efficient building of the same size. A total of 19 continuous design variables, including different concrete thicknesses, insulation thicknesses, absorbance of solar radiation for each exterior wall/roof and different window-to-wall ratios for each façade, are considered for optimization. The thermal load and annual discomfort degree hours are selected as the objective functions for optimization. Two prediction models, multi-linear regression (MLR) model and an artificial neural network (ANN) model, are developed to predict the building thermal performance and adopted as fitness functions for a multi-objective genetic algorithm (GA) to find the optimal design solutions. As compared to the original design, the optimal design generated by the MLRGA approach helps to reduce the thermal load and discomfort level by 18.2% and 22.4%, while the reductions are 17.0% and 22.2% respectively, using the ANNGA approach. Finally, four objective functions using cooling load, heating load, summer discomfort degree hours, and winter discomfort degree hours for optimization are conducted, but the results are no better than the two-objective-function optimization approach. [ABSTRACT FROM AUTHOR]

This article presents some of the findings from a thermal comfort study performed in subtropical China. This study was carried out in 17 different urban spaces during the summer of 2010. Thermal environmental measurements were taken and questionnaire surveys were used to assess the thermal comfort of subjects. Thermal comfort requirements and the effect of gender on thermal comfort were analysed. Neutral operative temperature was found to be 28.6°C and preferred temperature occurred at 24.7°C. By using the direct thermal acceptability assessment method, this article also demonstrated a new correlation between percentage of thermal dissatisfaction (PD) and thermal sensation vote (TSV) which is different from the predicted mean vote–predicted percentage dissatisfied model. The acceptable temperature range was 25.3–32.3°C in summer. Besides, the results show significant gender differences in urban spaces in terms of neutral temperature, preferred temperature and optimum wind speed. [ABSTRACT FROM AUTHOR]

This article focuses on the implementation of energy efficiency measures in a semiconductor building. Those measures include system optimization on the terminal units (TBs), office air-handling units (AHUs), make-up air units (MAUs), exhaust systems, fan filter units (FFUs), fan tower units (FTUs) and recirculation air-handling units (RAHs), fan coil units, and central chiller plant and boiler plant. Twelve permanent power meters were installed throughout the building to measure the total building electricity demand, solar generated electricity demand, HVAC and non-HVAC equipment demand to quantify the energy savings from the implementation of the energy efficiency measures. The electricity demand data have been collected for two years at 15-minute intervals and evaluated, with the energy saving adjusted by the outside air temperature. The electricity saving for this building is about 54.49 kWh/ft2/year (589.64 kWh/m2/year), which reduces the total building electricity consumption about 20%. The gas savings is about 0.1MMBtu/ft2/year (493 km3 of natural gas/year, 30% of the total building gas consumption) based on the daily reading from the facility engineer. The simple payback without incentives is 1.5 years. [ABSTRACT FROM PUBLISHER]

With the goal of carbon peak and carbon neutrality, fossil energy is becoming increasingly exhausted. Optimizing energy structure and saving energy and reducing consumption are the top priority. With the rapid development of modern science and technology, vacuum refrigerator has been greatly applied and popularized in various fields, such as food production, medicine and biology. However, in the actual operation process, the energy consumption of vacuum refrigerator is high, which does not meet the concept of energy conservation and environmental protection. The inner and outer push–pull structure of the sealing door makes it occupy too much space when opening the door, which is very inconvenient. In this paper, a vacuum refrigeration energy-saving device and the TRNSYS 16 software are used to simulate the energy-saving device. The results show that the device can reduce the number of vacuum refrigeration pumps and greatly reduce the loss of energy consumption. In addition, the new sealing door structure can also reduce the space occupied during its expansion and improve the utilization of space. [ABSTRACT FROM AUTHOR]

People in China spend about 85% of their time indoor, of which residential building accounts for about 50%. Furthermore, most residential dwellings do not have mechanical ventilation systems, and air infiltrates during heating and cooling seasons. Consequently, human inhalation exposure to particles of outdoor origin depends substantially on the degree to which particles can penetrate the building envelope and remain suspended in indoor air. In this paper, the impact factors of particle penetration are analyzed, and a mathematical model is developed to simulate particle penetration through cracks with rough/smooth inner surfaces. For smooth inner surfaces, the results from the mathematical model show good agreement with the experimental data; for penetration through actual building envelop, the results from the rough surface model shows better agreement than the smooth surface model. It is observed that the roughness of the cracks plays a more important role in influencing deposition of particles with diameter d <0.04μm. The roughness mainly influences the Brownian diffusion mechanism of particles deposition. Discrepancies exist between two models and experimental data for particles with diameter ranging from 0.075 to 0.54μm, which implies that inertia interception caused by roughness plays a more important role in enhancing deposition for particles in this range. The thermal property of the building shell is not an effective factor at removing infiltrated particles. [Copyright &y& Elsevier]

To design a lyophilizer plant in Guangzhou, the author of this paper used a solar energy absorption refrigeration system and a waste heat of solar absorption refrigeration system. Using Trnsys software, the simulation results show that the solar assurance rate of 74.96% on July 28th can save coal quantity of about 236.8 kg, a solar assurance rate of 53.48% in July can save coal quantity of about 4790.9 kg, and an annual solar assurance rate of 39.06% can save about 40657.1 kg, and each have good environmental benefits. [ABSTRACT FROM AUTHOR]

This paper proposed an optimization method to minimize the building energy consumption and visual discomfort for a passive building in Shanghai, China. A total of 35 design parameters relating to building form, envelope properties, thermostat settings, and green roof configurations were considered. First, the Latin hypercube sampling method (LHSM) was used to generate a set of design samples, and the energy consumption and visual discomfort of the samples were obtained through computer simulation and calculation. Second, four machine learning prediction models, including stepwise linear regression (SLR), back-propagation neural networks (BPNN), support vector machine (SVM), and random forest (RF) models, were developed. It was found that the BPNN model performed the best, with average absolute relative errors of 3.27% and 1.25% for energy consumption and visual comfort, respectively. Third, six optimization algorithms were selected to couple with the BPNN models to find the optimal design solutions. The multi-objective ant lion optimization (MOALO) algorithm was found to be the best algorithm. Finally, optimization with different groups of design variables was conducted by using the MOALO algorithm with the associated outcomes being analyzed. Compared with the reference building, the optimal solutions helped reduce energy consumption up to 34.8% and improved visual discomfort up to 100%. [ABSTRACT FROM AUTHOR]

A Chinese traditional narrow street, named Cold-Lane, can create a microclimatic zone that provides pedestrian thermal comfort under hot and humid climate conditions. This phenomenon was observed through experimental measurement during the summer of 2016. The heat transfer rate over the pedestrian body surface was calculated to reveal why pedestrians experience a cool sensation, and computational flow dynamics (CFD) simulation was carried out to study the influence of the street aspect ratio on the shading effect. It was found that the perception of thermal comfort can be attributed mainly to the radiation between the relatively cool surrounding walls and the human body, and the wind velocity has little effect on sensible heat dissipation. The cool horizontal and vertical surfaces in the street canyon are mainly due to the shading effect as a result of the small aspect ratio, which is a typical characteristic of the traditional Chinese street. The shading effect of the high walls on both sides creates the cooling effect of this narrow street. [ABSTRACT FROM AUTHOR]

1,4-dioxane should be less than or equal to 10 ppm in finished cosmetic products according to the recommendation of the Scientific Committee on Consumer Safety, but it is often generated as a by-product during the manufacturing process of poly(ethylene glycol) (PEG)-based derivatives. In order to avoid the possible risk caused by 1,4-dioxane, it might be a good choice for preparing cosmetic ingredients by using polyglycerin (PG) instead of PEG as a hydrophilic segment. In the present study, polyglyceryl-10 caprylates were synthesized by the esterification reaction between polyglycerin-10 and caprylic acid. FTIR and 1H NMR were utilized to confirm the chemical structures of the obtained polyglyceryl-10 caprylates. Light transmittance was availed to investigate the water solubility of polyglyceryl-10 caprylates. The self-assembly behavior, size, and size distribution of polyglyceryl-10 caprylates were investigated by dynamic light scattering. The makeup cleansing effect was also evaluated by in vitro and in vivo methods. Irritation was evaluated by hen's egg test-chorioallantoic membrane assay (HET-CAM). Results showed that polyglyceryl-10 monocaprylate could self-assemble into nanoparticles in the water at the concentration range of 2.5–10 wt% with a transparent appearance. The diameter of formed nanoparticles was around 100 nm with a narrow particle size distribution around 0.1 at the concentration of 2.5 wt% or 5 wt%. Polyglyceryl-10 monocaprylate exhibited good removal effect against makeup and excellent removal efficacy against pen eyeliner. The irritation of polyglyceryl-10 monocaprylate evaluated by HET-CAM at the concentration of 4 wt% was moderate irritant (irritation score = 8.4), which was lower than that of PEG-6 caprylic/capric glycerides (severe irritant, irritation score = 14.1). Therefore, polyglyceryl-10 monocaprylate might be a promising cosmetic ingredient for transparent makeup removing water. [ABSTRACT FROM AUTHOR]

This paper investigates the energy performances of a hybrid system composed of a phase change materials-ventilated Trombe wall (PCMs-VTW) and a photovoltaic/thermal panel integrated with phase change material (PV/T-PCM). Equivalent overall output energy (QE) was proposed for energy performance evaluation regarding different energy forms, diversified conversions and hybrid thermal storages. This study focuses on parameters' optimization of the PV/T-PCM system and parameters in the PCMs-VTW are kept optimal. Based on the experimentally validated numerical modelling, nine trial experiments have been conducted following Taguchi L9 (34) standard orthogonal array. The higher the better concept was implemented and the optimal combination of operating parameters was thereafter identified by using signal-to-noise (S/N) ratio and Analysis of Variance (ANOVA) method. The results show that QE is highly dependent on the mass flow rate, followed by the diameter of active cooling water pipe. However, the inlet cooling water temperature and the thickness of PCM have limited influence on QE. The optimal combination of each factor was identified as B3A3C2D1 (mass flow rate of 1 kg/s, diameter of water pipe of 0.6 m, inlet cooling water temperature of 15 °C and the thickness of PCM of 20 mm) with the highest QE of 20,700 kWh. [ABSTRACT FROM AUTHOR]

Abstract: It is favorable to increase the energy efficiency of an air-cooled chiller with an efficient, reliable and cost-effective method. Coupling a direct evaporative cooler with an air-cooled condenser seems to be a feasible solution to this problem. To maximize the energy saving potential of an evaporative air-cooled chiller (EACC), which composes of an evaporative air cooler and a conventional air-cooled chiller, a mathematical model was developed and a new index, increase of seasonal energy efficiency ratio (ISEER), was proposed to evaluate the energy saving potential of the evaporative air-cooled chiller. The energy saving potential of EACC was simulated by using the hourly weather data for four typical cities in China. The impacts of various factors on the energy saving potential were analyzed and it was found that there exists an optimal pad thickness which maximizes the energy saving. The optimal pad thickness varies with climatic condition and face velocity. Optimization results of the pad thickness in 31 main cities in China are presented. The maximum energy saving potential of EACC in China is between 2.4% and 14.0% depending on the climatic condition. It is necessary to determine optimal values for the design parameters according to different climatic condition for maximum energy saving. [Copyright &y& Elsevier]