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Bioaerosols are widely distributed in urban air and can be transmitted across the atmosphere, biosphere, and anthroposphere, resulting in infectious diseases. Automobile air conditioning (AAC) filters can trap airborne microbes. In this study, AAC filters were used to investigate the abundance and pathogenicity of airborne microorganisms in typical Chinese and European cities. Culturable bacteria and fungi concentrations were determined using microbial culturing. High-throughput sequencing was employed to analyze microbial community structures. The levels of culturable bioaerosols in Chinese and European cities exhibited disparities (Analysis of Variance, P < 0.01). The most dominant pathogenic bacteria and fungi were similar in Chinese (Mycobacterium: 18.2-18.9 %; Cladosporium: 23.0-30.2 %) and European cities (Mycobacterium: 15.4-37.7 %; Cladosporium: 18.1-29.3 %). Bartonella, Bordetella, Alternaria, and Aspergillus were also widely identified. BugBase analysis showed that microbiomes in China exhibited higher abundances of mobile genetic elements (MGEs) and biofilm formation capacity than those in Europe, indicating higher health risks. Through co-occurrence network analysis, heavy metals such as zinc were found to correlate with microorganism abundance; most bacteria were inversely associated, while fungi exhibited greater tolerance, indicating that heavy metals affect the growth and reproduction of bioaerosol microorganisms. This study elucidates the influence of social and environmental factors on shaping microbial community structures, offering practical insights for preventing and controlling regional bioaerosol pollution., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The energy consumption of office buildings has increased sharply since the 21st century with the increasing urbanization coverage. At this stage, the energy consumption of office buildings in China mainly comes from air conditioning and lighting. This paper obtains the regression equation of natural lighting illumination and radiant heat gain under different curtain conditions through experiments and simulations, and gives the theoretical calculation process of curtain regulation of office thermal and light environment and energy consumption. DeST and Ecotect software were used to analyze the thermal and light environment and energy consumption of the office. The results show that setting curtains in the room can effectively improve the indoor thermal light environment, the higher the transmittance of curtains the lower the lighting energy consumption, the higher the number of high temperature hours of natural room temperature and the greater the radiant heat gain. The room with thick curtains has the lowest energy consumption for air conditioning in summer, followed by the room with thin curtains, and the room without curtains has the highest energy consumption for air conditioning. The room without curtains has the lowest energy consumption for artificial lighting, the room with thin curtains has the second lowest, and the room with thick curtains has the highest electricity consumption for artificial lighting. The air conditioning energy consumption accounts for the main building energy consumption, followed by the lighting energy consumption. After setting curtains in the office, the air conditioning energy consumption caused by the solar radiation heat entering the room through the exterior windows is smaller than the lighting energy consumption caused by artificial lighting. Therefore, the installation of internal shading with moderate transmittance and good thermal insulation performance can make the energy saving of lighting and air conditioning energy consumption reach the optimal value. [ABSTRACT FROM AUTHOR]

Current requirements for residential energy-efficient design solutions in China are relatively homogeneous, requiring only improvements in overall building energy performance, often ignoring the energy differences between different residential housing units. This paper proposes a multi-objective research framework based on an occupant behavior model of air conditioning and a Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to study energy-efficient design solutions for residential envelopes. The optimal energy-saving design scheme has a 22.56% and 35.34% reduction in energy consumption difference between residential units and overall building energy consumption, respectively, both of which have been optimized substantially. Moreover, the overall energy performance of the building can be improved when the "energy performance difference between housing units" (EDH) is reduced, which verifies that EDH is an important criterion for improving the energy performance of residential housing units. [ABSTRACT FROM AUTHOR]

With the rapid development of the economy, carbon neutral and carbon peak are on the agenda in China, and the reform of intelligent construction and assembly building is in full swing in the Chinese construction industry. In order to further explore and study the relationship between the textural structural issues of the envelope structure and the overall energy consumption situation of the house, and further bridge the gap between the actual energy-saving design scheme and the actual application scheme, therefore, this paper takes a certain place as a research object to study the phenomenon of design assembly energy saving, based on dozens of assembly building enterprises researched, selected samples of envelope components studied, selected BIM technology for premodeling optimization, used neural network algorithm for analysis of influencing factors, and studied the application in the study of energy-saving optimization of assembly building envelope in the western Sichuan plain area, and used OpenStudio was used to build a model to simulate the heating and air conditioning load of the assembled building numerically and to fit the quantitative relationship between the variable factors and the building energy consumption. On this basis, the relationship between multifactor and single-factor variables is identified and evaluated using relevant variables means. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By comparison with cool roofs, the cooling energy produced by radiative cooling can be stored in hybrid radiative cooling air conditioning (HRcAc) systems, which is more feasible for the application of radiative cooling. A thermosyphon mainly relies on buoyancy to drive the water circulating in a pipe without a pump and has been widely used in solar thermal collectors. Thus, more cooling benefits can be achieved by integrating a thermosyphon with HRcAc. This paper investigated the cooling performance of a thermosyphon-based radiative cooler (STRC). The STRC was modelled by using OpenModelica to derive the effects of structure parameters on the cooling performance. The optimized structure was determined according to the proposed optimization process. Finally, the cooling energy saving potential and economics for the application of the STRC in a single-floor family house in five climate zones of China were evaluated. The results show that the annual cooling electricity consumption can be reduced by 41%–56% and that the simple payback period for a single-floor family house with an optimized STRC in all five climate zones of China is between approximately 8.4 years and 10.5 years. [ABSTRACT FROM AUTHOR]

The excessive simplification of occupant behavior is considered as the most important factor that affects the uncertainty of building performance simulation, thus affects the reliability and generalizability of simulation-based design and forecast. In this paper, occupant behavior in air-conditioned office buildings of the Pearl River Delta (PRD) region was investigated and defined. Copies of 873 questionnaires about the occupant behavior in air-conditioned office buildings in the PRD region were collected to study the relationship between indoor environment quality and adaptive behaviors. Eight typical office occupant schedules were defined via K-means clustering method. A probability prediction model of cooling temperature set-point was established by using the Ordinal Logistic Regression method. According to the different control modes of air conditioning, window, blind and lighting equipment, four types of typical behavior patterns were proposed using the K-prototype clustering method, which could be developed into 20 typical occupant behavior styles of office buildings in the PRD region. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, moisture buffering materials for interior finishing have received much attention for their ability to regulate indoor humidity passively. It is necessary to investigate the potential of such materials' moisture buffering performance before application because the effect is highly climate and material dependent. However, existing studies in China lack a comprehensive overview of the moisture buffering potential of different interior finishing materials throughout the large country with a wide spectrum of climates. This paper aims to outline the moisture buffering potential for office buildings in various climates in China through numerical methods. Specifically, simulations in 15 representative Chinese cities are conducted with five interior finishing materials under two heating, ventilation, and air conditioning (HVAC) scenarios. The results show that the moisture buffering materials hold a general potential to regulate indoor humidity conditions and reduce buildings' HVAC load. Such benefits are evident in the mild climate but weak in humid areas. The moisture buffering effect also displays significant seasonal variations and could worsen indoor humidity conditions in some cases, indicating the importance of utilizing moisture buffering materials properly. In addition, although moisture buffering materials can reduce the HVAC load, the reduction is limited, within 3 kWh/m2, in most simulated cases. The energy-saving benefits of moisture buffering materials should thus not be over-emphasized. Finally, suggestions are put forward to instruct the choice of interior finishing material according to climate and buildings' HVAC scenarios. [ABSTRACT FROM AUTHOR]

The exposure to extremely high temperatures varies across population groups. Those with better adaptation strategies (such as air conditioning) suffer less. This paper combines China's daily mean temperature data with comprehensive national survey data at the household level and estimates the relationship between high-temperature exposure and adaptation behavior of urban dwellers. We find that the usage of air conditioning and electric fans by urban households in China increases with their summer high-temperature exposures. The rise in the number of days with extreme heat (mean temperature exceeding 80 °F) induces the purchase and use of air conditioning. High-temperature adaptability varied across households-the rich are more likely to increase air conditioning usage to cope with the high-temperature discomfort; while the poor are less likely to afford such a market product for adaptation, they suffer more from high-temperature exposure. Such a variation in the affordability and usage of market products to adapt to climate risks will exacerbate the climate-induced inequality., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Copyright of South Architecture / Nanfang Jianzhu is the property of South Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Solar photovoltaic driven air conditioning (PVAC) system with electricity storage is proposed as a good solution to help shifting peak load and consuming solar energy. In this paper, a grid-connected PVAC system using the TRNSYS simulation model consisting of PV panels, traditional air conditioners (TAC), power conditioning units, inverters, and grid connection equipment is proposed to investigate the economic feasibility compared with the traditional air conditioner. In the PVAC system, the electricity, firstly generated by PV panels and then stored in battery, is consumed by a DC inverter air conditioner to maintain the temperature of the room and the surplus electricity is sold to the grid. A life cycle cost comparison between PVAC system, traditional air conditioning system, and decomposed PV and air conditioning systems of three typical application cases is conducted, in which the operation conditions are based on the present circumstances of China. The results show that, in comparison with conventional air conditioners, better economic benefits can be achieved when the peak load of the air conditioning system is over a certain value. Sensitivity analysis is conducted to evaluate the effects caused by variation of economic assumptions. At last, a new operation model is proposed to achieve more benefits for the system. [ABSTRACT FROM AUTHOR]

The thermal comfort inside heritage buildings in China is mostly achieved with the use of split air conditioning and radiator heating system. Due to inefficiencies in the design of those systems, the regulation of air temperature is generally inadequate. To meet the thermal comfort requirements of the partial significant room, which is the meeting hall area, and to preserve the external walls and facade, this paper simulates and analyses typical working conditions of air control schemes in the gate tower and suggests the use of a floor-type fan coil air conditioning system. The results show that the proposed air distribution system can maintain a temperature of 295 K in the summer, which meets the thermal comfort requirements of the meeting hall. This method takes into account the requirement for thermal comfort, as well as the requirements of heritage preservation. Our proposal contributes to the growing literature, which studies methods of improving the thermal comfort of the indoor environment of heritage buildings. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of prenatal exposure to extreme temperatures on birth outcomes—specifically, the log of birth weight and an indicator for low birth weight—using a nationally representative dataset on rural China. During the time period we examine (1991–2000), indoor air conditioning was not widely available and migration was limited, allowing us to address identification issues endemic in the climate change literature related to adaptation and location sorting. We find substantial heterogeneity in the effects of extreme temperature exposure on birth outcomes. In particular, prenatal exposure to heat waves has stronger negative effects than exposure to cold spells on surviving births. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Design days are the fundamental parameters for design cooling load calculations. At present, the coincidence and coupling relationship of meteorological elements are ignored by the design-day selection methods provided in the current standards, which results in conservative and unreasonable designs. This research proposes a method of selecting design days for design cooling load calculation that considers the coincidence and correlation of meteorological elements. First, a joint distribution function is constructed; on this basis, the coincident near-extreme meteorological parameters are selected. Then three meteorological elements from a 30-year meteorological record are integrated into one single normalization parameter. Finally, a design day reflective of the variation trend of near-extreme climate conditions is selected from the meteorological record. This paper uses Tianjin in China as an example to generate the research design day. It was found that the outdoor non-guaranteed rate of the research design day is roughly consistent with the corresponding indoor thermal environment risk level. Compared with the standard Chinese design day, the peak values of the research design day are reduced effectively, and the gap between the indoor thermal environment risk level and the outdoor non-guaranteed rate is narrowed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Research (2307-1877) is the property of Kuwait University, Academic Publication Council and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conventional air conditioning system used in high-speed railways has limitations in heating performance and environmental impact, necessitating the exploration of alternative refrigerants. The transcritical CO 2 system has gained popularity due to its exceptional heating efficiency and environmental benefits. This study aims to evaluate the energy and environmental potentials for transcritical CO 2 systems in high-speed trains based on four-vertical-and-four-horizontal railway lines within different climatic regions of China. A high-fidelity transcritical CO 2 system model was first developed and validated through experiments. Then, a comprehensive energy and environmental evaluation method was proposed and applied to the four-vertical-and-four-horizontal railway lines. The results indicated that the transcritical CO 2 system had a superior heating performance and competitive cooling performance based on daily and annual operations. Furthermore, the transcritical CO 2 system exhibited significant environmental advantages with lower total life cycle climate performance for all lines, with an average emissions reduction ratio of 17.6% and a maximum emissions reduction ratio of 26.98%. These findings highlight the competitive energy performance and outstanding environmental benefits offered by transcritical CO 2 systems as promising alternatives to air conditioning systems in railway transportation. • This paper evaluates the potential of theCO 2 system in high-speed trains from an energy performance and environmental benefits perspective. • A high-fidelity model of the transcritical CO 2 system is developed and validated for effectiveness through experiments. • The energy and environmental evaluations are conducted based on China's four-vertical-and- four-horizontal railway lines. • The results indicate that the CO 2 system presents a competitive alternative for air conditioning systems in high-speed trains. [ABSTRACT FROM AUTHOR]

• Comparison of three AC systems in different climate regions was conducted. • Reheat energy consumption accounts for the large proportion in split AC system. • The SDAC system has the best temperature control. • The LDAC system has the best relative humidity control. • A dividing line is developed to achieve the suitable AC system in different areas. Liquid desiccant air conditioning (LDAC) system and solid desiccant air conditioning (SDAC) system have strong dehumidification capability. To evaluate and compare their feasibility and applicability, performance analysis of these two air conditioning systems and the conventional split air conditioning (AC) system in apartment buildings was conducted under different climates in China. Results show that SDAC system has the best temperature control and LDAC system has the best relative humidity control with the same requirements. In hot and humid cities, 45% relative humidity can be reached and stably maintained by LDAC system in summer when the relative humidity set point is 50%. While for apartment building controlled by split AC system and SDAC system, indoor air relative humidity could even reach 65% in summer. LDAC system is most efficient in hot and humid cities. In cold and dry cities, split AC system performs better than other two systems. Moreover, a dividing line between areas where LDAC system is more efficient and areas where split AC system is more efficient is developed in this paper. Areas where LDAC system is more efficient are mainly distributed in the coastal areas, Yangtze River basin and south of the Yangtze River. [ABSTRACT FROM AUTHOR]

The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation.

In order to ensure the cleanliness of operating room, clean air conditioners are installed in the clean operation departments in hospitals in China. Purification air conditioning system is an air conditioning system with a special function that ensures the cleanliness of the operating room and the required temperature and humidity in the operating room to avoid infection. This paper took the energy-saving design of the clean air-conditioning system of the clean operation department of the First Affiliated Hospital of Wenzhou Medical College, Zhejiang, China, as an example to illustrate the energy-saving methods such as layout optimization, air-conditioning division, secondary return air setting and operation mode adjustment. The energy consumption of primary return air technology and secondary return air technology was calculated. The results showed that energy-saving design could save nearly one-third of energy, improve the level of air-conditioning operation and management, reduce costs, and improve resource utilization, which is of great significance to social development. [ABSTRACT FROM AUTHOR]

In order to explore the thermal characteristics and thermal storage performance analysis of energy-saving phase change heat storage materials in buildings, taking the common exterior wall insulation composite wall structure in southwestern China as an example, the influence of insulation board structure thickness design on the total cost of residential air conditioning energy consumption and insulation board cost is studied, thus clarifying the concept and calculation origin of economic insulation thickness. The experimental results show that by drawing mathematical functions of energy consumption cost, total cost, and insulation material cost in the same 2-D co-ordinate, it is intuitively demonstrated that the minimization of total cost can be ensured when the insulation thickness is in an economic state, and the specific economic thickness can be accurately calculated through example data. Therefore, specific measures for improving external wall insulation from refined insulation structure design are proposed. It has been proven that the design of the exterior wall insulation layer structure is an important way to improve the overall energy-saving benefits of building exterior wall insulation. [ABSTRACT FROM AUTHOR]

• The principle of difference information and the principle of minimum information are discussed. • The proposed method can deal with the environment problem in other regions. • The unequal adjacent accumulation multivariate grey model is used to forecast the public concern about air pollution. In grey theory, the principle of difference information holds that difference is information. To mine the difference information between data, the unequal accumulation is proposed in this paper. The unequal accumulation reduces the loss of difference information and improves the forecasting performance of the grey model. Based on the unequal accumulation, the unequal adjacent discrete multivariable grey model is proposed. According to the comparison with other models, the proposed model has good forecast performance and algorithm efficiency. To further prove the practical significance of the model, it is used to predict the public concern about air pollution in three cities of China. The results show that the public concern about air pollution in cities with different air pollution conditions is quite different. Environmental protection departments could pay attention to the public concern about air pollution to better control air pollution. [ABSTRACT FROM AUTHOR]

Hotel guest perception of Indoor Environmental Quality (IEQ) is significant for both hotel management and IEQ research. This paper used a novel text-mining methodology to analyse guest perception of IEQ through online hotel reviews. More than 160,000 reviews from 70 five-star hotels were collected from Ctrip.com, the largest travel website in mainland China. Next, a list of IEQ keywords were programmed to extract specific IEQ problems from these reviews. Finally, a complaint indicator was proposed to evaluate customer IEQ dissatisfaction. The results showed an average of four complaints (about indoor environment) per one hundred online reviews. Air conditioning, noise, and humidity were the top three factors influencing guest IEQ satisfaction, representing 39, 23, and 19%, respectively. This paper also revealed that a higher IEQ complaint rate resulted in a lower online rating; as such, IEQ rate indirectly affected the business performance of the hotel. This research also considered the baseline energy consumption of 5-star hotels; if the annual energy consumption was lower than 150 kWh/m 2 a, then indoor environmental performance was significantly compromised. However, if energy consumption was higher than 150 kWh/m 2 a, then there was no obvious negative correlation between the IEQ complaint rate and energy consumption. [ABSTRACT FROM AUTHOR]

The applications of conventional heat pipes have been hindered by a few weaknesses, such as the low heat recovery effectiveness, the cross-pollution of fresh and exhaust air, and the difficult switch modes between winter and summer working conditions. In order to find solutions for those problems, a three-dimensional heat pipe exchanger was developed, and an experimental platform was built to test the heat recovery effectiveness of this heat pipe exchanger under different working conditions. Moreover, the operating performances of the three-dimensional heat pipe exchanger unit were monitored throughout one year in a hospital located in the hot summer and cold winter region of China. The field measurement results indicated that the heat recovery effectiveness could be effectively improved by reducing the air volume and the up-wind speed, increasing the cold air and hot air inlet temperature, and increasing the rows of pipes. According to optimizing the structure and operation parameters, the heat recovery efficiencies of the three-dimensional heat pipe exchanger increased by 65~85%. The recommended operation parameters of the three-dimensional heat pipe exchanger in winter and summer for indoor exhaust air temperature were 20 ± 2 °C and 22 ± 2 °C, respectively. The heat recovery effectiveness could reach up to 66% and 64.5% when the indoor and outdoor air temperature differences were higher than 11 °C and 5 °C in winter and summer, respectively. This study provides effective, reliable, and easily implementable methods for the application of three-dimensional heat pipe heat recovery devices in building HVAC systems. It offers guidance for the future design of heat pipe heat recovery devices. [ABSTRACT FROM AUTHOR]

• A dual-evaporator system couples with a new fresh air conditioner. • Five independent affecting parameters are included for parametric analysis. • Four typical cities are selected for energy-saving potential evaluation. • Average seasonal energy-saving rate is 48.87%. • Average seasonal power saving per hour is 24.85 W m−2. Energy recovery, evaporative cooling and multiple evaporator are regarded as the effective and energy-efficient techniques to improve the energy efficiency of air conditioning system and reduce building energy consumption. In this paper, a parametric analysis and energy-saving potential evaluation for a new hybrid air conditioning system (HAC) under hot-humid climates are carried out theoretically based on detailed models. The proposed HAC incorporates into a dual-evaporator air conditioning system with an independent fresh air conditioner for both total and sensible energy recovery. One evaporator is installed between the total and sensible energy recovery loop of the fresh air conditioner to deeply dehumidify the fresh air for indoor humidity control. The other evaporator is installed inside the conditioned room to handle the indoor return air for temperature and humidity independent control. The parametric analysis mainly for the effect of air-to-water heat capacity ratio, ambient temperature, enthalpy-humidity ratio of the air-conditioned room and the number of heat/mass transfer units of the internal heat exchangers. The energy-saving potential of the HAC is also evaluated for applications in four typical cities (Changsha, Guangzhou, Fuzhou and Hangzhou) located in southern China over the summer period (June–August). The results show that, for the same air supply requirement, the HAC has an average energy-saving rate of 48.87% compared to conventional system with electric heater, and its power saving per hour is 24.85 W m−2. [ABSTRACT FROM AUTHOR]

• Proposed hybrid system incorporates a fresh air conditioner with refrigerant system. • Fresh air conditioner has a heat-exchanger network for two-stage energy recovery. • Four independent affecting parameters are included for parametric analysis. • Optimum air-water heat capacity ratio of packed tower is found to be between 0.4–0.6. • Average energy-saving rate of the proposed hybrid system is 44.0%. Energy recovery technologies can effectively improve the energy efficiency of air-conditioning systems and significantly reduce building energy consumption. In this paper, a parametric analysis and energy-saving potential evaluation for a new hybrid air conditioning system (HAC) is carried out theoretically based on developed models. The proposed HAC incorporates into a conventional mechanical vapor compression air conditioning system with an independent fresh air conditioner which is composed of a network of heat exchangers, including a packed bed and three air-water finned coils. Under cold winter climate, in the fresh air conditioner, a packed bed is coupled with a water-air heat exchange coil to form a total energy recovery loop. A run-around sensible energy recovery loop is also integrated in the system to produce a two-stage energy recovery effect. Moreover, a sprayer is installed upstream of the two-stage energy recovery process for fresh air humidification, and a fresh air recirculation duct is equipped for frost-free operation. In the parametric analysis, four independent affecting parameters are included: the air-to-water heat capacity ratio, the indoor temperature, the ambient temperature, and the ratio of recirculation fresh air. The energy-saving potential of the HAC is also evaluated for applications in seven typical cities located in middle-lower Yangtze River region of China over the winter period (December, January and February). The results show that compared with the conventional system with electric humidification, the HAC has an average energy saving rate of 44.0%, and its average power saving per hour is 13.41 W m−2. [ABSTRACT FROM AUTHOR]

With increasing consideration on public health, the cleaning industry for central air-conditioning systems has been flourished in China with the rapidly developed of both duct-cleaning technology and cleaning robots. By testing the performance on the experimental platform, this paper presents the cleaning effect and motion performance of the duct-cleaning robot designed by our expert group. The result indicates that the cleaning effect is not satisfied at corners and elbows, where the pollution is relatively serious. At the end of this paper, it points out the development direction for China's duct-cleaning robot and its experimental platform, which can provide an important basis to standardize the test platform, tools and methods for the evaluation of robot's performance. [ABSTRACT FROM AUTHOR]

Interior decorating coatings (IDCs) are the heat-transfer medium between indoor air and building walls, which mainly form the cooling load and are important in an indoor built environment. To explore the impacts of the precooling process of IDCs on indoor thermal environment of occupants during intermittent air conditioning, this paper investigated the dynamic thermal response of IDCs. Three representative coating materials were integrated to the external insulation wall and internal insulation wall, and their interior surface temperatures were experimentally tested under intermittent air conditioning operation in southern China. Moreover, a heat transfer model was established and verified to analyze the influences of IDC on the thermal response of the interior surface. During the pull-down process, the cold was accumulated in the IDC layer with small thermal diffusivity and could not be transferred into the wall inside, so that the largest temperature reduction was obtained, meaning that the indoor thermal environment could meet the setpoint in a short time. According to modelling calculations, the thick IDC with volumetric specific heat capacity less than 1 × 105 J/(m3·K) and small thermal conductivity integrated to the internal insulation wall was beneficial to increase the thermal response rate and had the better energy-saving efficiency. [ABSTRACT FROM AUTHOR]

Exploring how urban form affects the Particulate Matter 2.5 (PM2.5) concentration could help to find environmentally friendly urbanization. According to the definition of geography, this paper constructs a comprehensive urban form evaluation index system applicable to many aspects. Four urban form metrics, as well as road density and five control variables are selected. Based on 2015 data on China's 340 prefecture-level cities, the spatial regression model and geographically weighted regression model were used to explore the relationship between the urban form evaluation index system and PM2.5 pollution. The main results show that the spatial distribution of PM2.5 in China follows an increasing trend from northwest to southeast. Urban form indicators such as AI, LPI, PLAND, LSI and road density were all significantly related to PM2.5 concentrations. More compact urban construction, lower fragmentation of urban land, and lower density of the road network are conducive factors for improving air quality conditions. In addition, affected by seasonal changes, the correlation between urban form and PM2.5 concentration in spring and winter is higher than that in summer and winter. This study confirmed that a reasonable urban planning strategies are very important for improving air quality. [ABSTRACT FROM AUTHOR]

• Urban environmental degradation hinders the choice of migrants to settle in cities. • There is a structural characteristic underlying the environmental effect on migration intentions. • Environmental degradation causes a wave effect on migrants' settlement intentions. • Cities should improve their environmental quality to attract migrants in the future. In the existing literature, it has been indicated that there is a negative link between air pollution and the settlement intentions of migrants. However, the underlying mechanism is still sleeps in the unopened black box. Based on China Migrants Dynamic Survey data, this paper applies a two-step conditional maximum likelihood method and quantile regression method to analyze the mechanism underlying environmental migration. The results confirm a nonlinear relationship between air quality and migrants' settlement intentions. Different conditions of air quality differences between cities will lead to structural changes in the settlement intentions of migrants. Specifically, the real curve falls first decreases, increases and then decreases again. Under specific urban environment dimensions, the paper provides a new policy path for urban decision-makers on how to coordinate the human capital of migrants and sustainable urban development. [ABSTRACT FROM AUTHOR]

• Air conditioning load reduction strategy in vehicles using recirculated air is provided. • Utilizing the recirculated air can extent the annual driving range by 11−30%. • Energy saving of heat pump heating in electric vehicle air conditioning is provided. The stock of electric vehicle is booming recently. However, the range of the electric vehicle is still a main barrier in its adoption. Air conditioning system is the second largest energy consumption device on vehicle, which will cause significant range reduction during operation. In this paper, the energy-saving effect of utilizing the recirculated air in air conditioning system is evaluated. The outside air ventilation rate based on CO 2 limits and windshield anti-fog requirements are calculated, and the energy-saving effect of this strategy in 30 cities across China is evaluated using an annual energy consumption model. It is found that utilizing the recirculated air can save 14–46% heating energy when using PTC heater, and 33–57% heating energy in heat pump AC system. Throughout a year, utilizing the recirculated air can extend the driving range by 11–30%. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Exposure to air pollution is one of the greatest environmental risks for human health. Air pollution level is significantly driven by anthropogenic emissions and meteorological conditions. To protect people from air pollutants, China has implemented clean air actions to reduce anthropogenic emissions, which has led to rapid improvement in air quality over China. Here, we evaluated the impact of anthropogenic emissions and meteorological conditions on trends in air pollutants in a coastal city (Lianyungang) in eastern China from 2015 to 2022 based on a random forest model. The annual mean concentration of observed air pollutants, including fine particles, inhalable particles, sulfur dioxide, nitrogen dioxide, and carbon monoxide, presented significant decreasing trends during 2015–2022, with dominant contributions (55–75%) by anthropogenic emission reduction. An increasing trend in ozone was observed with an important contribution (28%) by anthropogenic emissions. The impact of meteorological conditions on air pollution showed significant seasonality. For instance, the negative impact on aerosol pollution occurred during cold months, while the positive impact was in warm months. Health-risk-based air quality decreased by approximately 40% in 8 years, for which anthropogenic emission made a major contribution (93%). [ABSTRACT FROM AUTHOR]

This paper mainly focuses on the applicability of solar liquid desiccant air conditioning in Xiamen area. We has carried out the following research works: the principle and the feasibility analysis of the solar liquid desiccant air conditioning; design of the solar solution liquid desiccant system; the analysis of solar energy utilization potential combined with the characteristics of Xiamen climate. Based on the economic analysis of the solar desiccant air conditioning in Xiamen, the applicability of the system was prospected. [ABSTRACT FROM AUTHOR]

Emission reduction in buildings is essential to combat climate change. However, current strategies failed to balance development and emissions reduction goals. This paper selects a public building in China and simulates its initial energy consumption and carbon emissions. Then it establishes a multi-objective optimization model to explore cost-effective and emission-reduction strategies, considering photovoltaic and ground-source-heat-pump (GSHP) systems. Finally, NSGA-Ⅱ is used to solve, and sensitivity analysis is carried out. Results show that: (1) Energy consumed by the air conditioning system is the largest in January for heating and in July for cooling, validating the accuracy of the energy simulation model. (2) Economic efficiency and emission reduction effect are better when photovoltaic and GSHP systems are implemented simultaneously. (3) Electricity price, initial investment cost, annual solar peak hours, and the proportion of shallow geothermal energy significantly impact carbon emissions and cost. (4) The photovoltaic and power grid substitution ratio will exceed 8% every five years, and all substitutions will be completed in 2050. After adopting the GSHP system, the complete replacement will be advanced to 2045. Setting subsidies significantly shortens the payback period of investment and ensures firms' economic benefits. In summary, using photovoltaic and shallow geothermal energy is conducive to reducing emissions and saving costs in the long term. [ABSTRACT FROM AUTHOR]

Various organizations and societies around the globe have issued guidelines in response to the coronavirus disease (COVID-19) and virus (SARS-CoV-2). In this paper, heating, ventilating, and air-conditioning-related guidelines or documents in several major countries and regions have been reviewed and compared, including those issued by the American Society of Heating Refrigerating and Air-Conditioning Engineers, the Federation of European Heating, Ventilation, and Air Conditioning Associations, the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, Architectural Society of China, and the Chinese Institute of Refrigeration. Most terms and suggestions in these guidelines are consistent with each other, although there are some conflicting details, reflecting the underlying uncertainty surrounding the transmission mechanism and characteristics of COVID-19 in buildings. All guidelines emphasize the importance of ventilation, but the specific ventilation rate that can eliminate the risk of transmission of airborne particulate matter has not been established. The most important countermeasure, commonly agreed countermeasures, the conflicting content from different guidelines, and further work have been summarized in this paper. [ABSTRACT FROM AUTHOR]

At present, China's high-speed rail is in a period of rapid development. Most of the refrigerants used in Chinese motor train units at this stage are still R134a and R407c, which have an impact on the environment. In response to the environmental protection concept of green travel, it is of great significance to study the air conditioning system of motor train units using CO2 refrigerant. Using CFD simulation analysis technology, the heat transfer performance of the air side of the CO2 finned tube evaporator used in the air conditioning system of the motor train unit is studied. We select the air outlet temperature, pressure drop, heat transfer factor, and resistance factor as the objective function, in addition, monitoring points are set up in the air flow channel to monitor the turbulent flow field and pipe wall pressure. Our research shows that the cooling capacity of the CO2 evaporator can reach up to 29.76 kW, which can meet the heat exchange required in the air conditioning system of the motor train unit. In order to obtain a better structure and the conditions of the heat transfer effect, structural optimization was conducted. The simulation results demonstrate several trends: (i) With the augment of the air inlet velocity, the cooling capacity of the evaporator increases and the heat exchange effect improves; when the air inlet ve > 2.2 m/s, the effect of continuing to augment ve on heat exchange is weak. (ii) Following appropriate reduction of the diameter of the heat exchange tube, the wind resistance is reduced and the cooling capacity of the evaporator is improved. (iii) With the enlargement of the fin spacing, the turbulent motion in the flow channel can be fully developed, there is a peak in the change in the heat exchange tube area optimization factor, and the optimal fin spacing is between 1.6 mm and 1.7 mm; at this time, the average turbulent kinetic energy of the air side is larger and the turbulent dissipation rate is smaller. These results provide a reference for the practical application of CO2 refrigerant in the motor train unit. [ABSTRACT FROM AUTHOR]

Heat pump technology fully shows the principle of energy recycling in terms of Heating, Ventilating and Air Conditioning (HVAC). It avoids unipolarity of energy using in the conventional HVAC system. Heat pumps use high-grade energy as a driving energy, recovering and upgrading low-grade energy for avail, like a pump. Because heat source used in HVAC usually is low temperature heat, heat pump systems adopted in HVAC will help improve heating performance coefficient. Therefore, HVAC is one of ideal users of heat pump applications, and thus high-grade energy used in HVAC can be replaced with a large number of low-temperature renewable energy. Through the heat pump technology, natural low-grade energy stored in the soil, water, air or waste heat from variant industries and daily lives, is supplied for building cooling/heating and hot water serving. Therefore, vast applications and developments of heat pump technology are presented in HVAC in China, and some progresses are achieved in the system innovation, experimental research, product development and engineering application, etc. This paper reviews the progress of researches, applications and development in the field of heat pumps for building cooling/heating in China since the 21st century. [ABSTRACT FROM AUTHOR]

Traditional heating systems, such as kangs (bed-stoves), radiators driven by mini-stove, and burning caves have been still widely used to tide over the long cold winter in most rural areas of northern China. In this paper, emissions and components of exhausting smoke from biomass burning during the heating and cooking period in rural areas, which have been measured. In addition, the impacts of the CO and PM2.5 concentration on the air pollution inside and outside the rural house has been studied and discussed. Different combustion efficiency of various fuels and energy consumption modes impact on the indoor air quality of rural houses are very significant. CO, NOx and other inhalable particles emission from rural areas surrounding the urban areas could not be overlooked. A low-cost way to improve indoor living environment and outdoor ecological environment to local conditions must be sought. [ABSTRACT FROM AUTHOR]

The Solark I Prototype was Southeast University's proposal for Solar Decathlon China 2013. This paper presents the prototype's passive strategies, active systems and performance results. The limitations, future perspectives and potential for replicability and transposition of Solark I are also discussed. Through a whole-building design process, Solark I effectively integrates all aspects of weather data analysis, building design, building envelope design, photovoltaic system design, solar hot water system design and heating, ventilating, and air conditioning system design to minimize energy consumption and environmental impacts. Solark I achieved an excellent balance between passive strategies and highly efficient active systems. These design decisions help Solark I to maintain its hydrothermal comfort and perform all regular tasks with minimum energy consumption. This low energy consumption allows Solark I to obtain a positive energy balance both in annual energy simulations and on-site during the monitored period. [ABSTRACT FROM AUTHOR]

China has been the world's largest producer and consumer of air conditioners, and more and more RACs 1 1 The RACs is short for room air conditioners. would be owned by China's households along with the rapid economic development. Air Conditioner is also considered as one of the largest potential contributors to energy reduction among home appliances because of the huge energy consumption. Therefore, the national energy efficiency standards were issued to promote the use and production of high-efficient RACs. According to China's energy efficiency standards, this paper investigated the electricity savings and CO 2 emission reductions from RACs over the period of 2005–2025. The results indicate that the rural RAC market which develops more slowly than the urban one still has great potential, and government has to revise subsidy policies to make the standards more effective, especially for rural areas. In 2025, the total electricity consumption of RACs is projected to be 598–674 TW h, while the amount without energy efficiency standards is 753 TW h. From 2005 to 2025, the energy efficiency standards for RACs can save 1430–2540 TW h electricity and reduce 908.3–1610. 1 Mt CO 2 emissions in different scenarios. Finally, we suggest that the standards should be revised every 4 or 5 years with higher revision pace of 8% to 10% [ABSTRACT FROM AUTHOR]

The contradiction between the shortage of urban land and the demand for urban green space needs to be solved reasonably. Different from urban parks, the cooling effect of small green space (SGs) has not been paid enough attention or fully evaluated. The major objective of this research was to explore the cooling and energy saving benefits of SGs with administrative units. The ENVI-met and EnergyPlus models were built based on field measurements on the green space of Xi'an Jiaotong University Qujiang Campus. Field measurement shows that the closer an area to the green space, the lower the air temperature and the higher the relative humidity, especially in the daytime. The ENVI-met results showed that the SGs can reduce the temperature by 0.66 °C within the range of 1260 m × 1350 m compared with the building scene at noon, the EnergyPlus simulation results showed that the building 100 m away from the SGs can reduce the air conditioning energy consumption by 2.1% compared with the distance of 150 m. The research can improve the planning and design standards of urban green space, clarify the cooling and energy saving benefits of SGs, and promote the ecological urban design. [ABSTRACT FROM AUTHOR]

We examine the distributional effects of high temperature on worker performance and the effectiveness of adaptation when capital investments such as air conditioning are not feasible. Using a longitudinal data set of 3196 professional archers in 57 competitions during 2010–2016 in China, which includes accurate performance measures at the individual‐by‐contest level, we show that heat causes more uneven performance distributions by hurting the bottom performers more than the top performers. More frequent heat reduces average performance and raises distributional inequality more than increases in average temperature. Gaining experience and long‐term acclimatization together can mitigate 70% of the heat impacts, demonstrating the potential of adaptation. [ABSTRACT FROM AUTHOR]

Using résumé data from a large Chinese online job board, we explore how daily fluctuations in air pollution affect workers' mobility intentions in China. Users can update their résumés daily to attract employers' attention, reflecting their intentions to relocate from the city of residence to the desired destination city for work. We find that daily differences in the air quality index (AQI) between the city of residence and destination city significantly affect workers' mobility intentions. A one-unit decrease in the daily relative AQI (destination AQI—residence AQI) leads to a 0.018% increase in the number of workers willing to relocate on that day, indicating that air pollution has a "push–pull" effect on labor mobility intentions. This effect is stronger when air pollution is more severe locally than in the destination city and for workers aged 25–40, with higher educational levels, and from more developed cities. These results suggest that workers may be influenced by temporary air pollution conditions when deciding whether to relocate for work; this influence is potentially explained by the psychological mechanisms of salience and projection bias. [ABSTRACT FROM AUTHOR]

The climate of Yangtze River Basin in China is cold and humid in winter. Conventional air-conditioning systems may cause high energy consumption and uncomfortable microclimatic conditions especially for lower body of indoor occupants. This study investigated four personalized seat heating systems, in a typical office room in Shanghai during winter, based on heated floor panels including heated floor panels + ordinary chair (HF-OC), heated floor panels + insulated chair (HF-IC), heated floor panels +insulated chair and leg box (HF-IC-LB) and overall personalized heating (OPH). The surface temperature of walls and heated floor panels, and the indoor air temperature at different positions were recorded with thermocouples. The hourly energy consumptions of the proposed personalized seat heating systems were measured and compared with a conventional split type air conditioner. Questionnaires of thermal sensation and comfort were carried out among 10 university students. Compared with HF-OC, HF-IC could improve the thermal comfort to a certain extent, while HF-IC-LB provided the optimal thermal micro-environment for the lower body other than other body parts. The OPH systems were proven effective to provide satisfactory thermal environment for all body parts at lower indoor temperature (12–16°C) with much less energy consumption than room air conditioners. [ABSTRACT FROM AUTHOR]

Air pollution is substantially modulated by meteorological conditions, and especially their diurnal variations may play a key role in air quality evolution. However, the behaviors of temperature diurnal cycles along with the associated atmospheric condition and their effects on air quality in China remain poorly understood. Here, for the first time, we examine the diurnal cycles of day-to-day temperature change and reveal their impacts on winter air quality forecasting in mountain-basin areas. Three different diurnal cycles of the preceding day-to-day temperature change are identified and exhibit notably distinct effects on the day-to-day changes in atmospheric-dispersion conditions and air quality. The diurnal cycle with increasing temperature obviously enhances the atmospheric stability in the lower troposphere and suppresses the development of the planetary boundary layer, thus deteriorating the air quality on the following day. By contrast, the diurnal cycle with decreasing temperature in the morning is accompanied by a worse dispersion condition with more stable atmosphere stratification and weaker surface wind speed, thereby substantially worsening the air quality. Conversely, the diurnal cycle with decreasing temperature in the afternoon seems to improve air quality on the following day by enhancing the atmospheric-dispersion conditions on the following day. The findings reported here are critical to improve the understanding of air pollution in mountain-basin areas and exhibit promising potential for air quality forecasting. [ABSTRACT FROM AUTHOR]

Energy efficient building projects has become the focus of sustainable development. In this article, 2 indexes, energy-saving sensitivity and energy-saving contribution, are proposed to assess the energy efficiency of residential buildings. Four green measures to improve the energy efficiency of residential building with either passive or active technologies are designed and their saving performances are evaluated with the case study of a residential building simulation model in Changchun, region in China using the 2 indexes by simulations in the Designbuilder simulation software. The results reveal that improving the energy efficiency of residential buildings in severely cold regions should be focused on two key energy consumption factors, A1-heating (gas) and A2-zone sensible heating. Green measures M4-modifying the heating ventilating and air conditioning system and M1-improving envelope structures are found with high energy-saving sensitivities on the energy consumption factors A1 and A2. The energy-saving contribution of green measures M4 is the largest with the value of 80.17%, and that of green measure M2-adding shading facilities is the smallest with the negative value of − 8.53%. These results suggest that M4 and M1 are the effective green energy-saving renovation measures of the residential buildings in severely cold regions. The assessment method and simulation case study results provide a theoretical foundation and practical suggestions for the decision making to effectively reduce the energy consumption of residential buildings in severely cold regions by adopting appropriate green measures. [ABSTRACT FROM AUTHOR]

Currently, more than 70% of the heated floor area in northern China is heated by coal, which severely burdens energy consumption and the environment. Hence, heating in this area is in urgent need of a shift to cleaner approaches. However, current progress is mainly attributed to the generous and unsustainable subsidies of the government, which have become a considerable financial burden. This paper develops a linear recursive dynamic model to identify economical, clean heating pathways in northern China. Different heating demands and clean technology promoting advances are considered. The results show that rapid promotion of clean heating technologies would save 1161–3026 Mtce (million tons of standard coal equivalent) of energy and avoid 7692–8843 Mt CO 2 , 12–13 Mt CH 4 , 8–9 Mt SO 2 and 7–8 Mt BC emissions cumulatively from 2020 to 2050. For rural residential buildings, biomass pellet furnaces, air source heat pumps and air conditioning should each contribute to about 30% of the heating demands in 2050 to achieve clean heating. However, coal-fired cogeneration should be the major method of coal heating, and mainly serve urban residential buildings and commercial buildings. The consequent energy cost savings of a faster clean heating transition would exceed the increase in investment costs and operational costs. Therefore, promoting clean heating as early as possible is the economical and environmentally friendly choice for northern China in the long run. [ABSTRACT FROM AUTHOR]

• Develop a dispatching scheme for DSUC incorporating multi-function demand response. • Design the LS and RC demand response to improve flexible ramping capability. • Accelerating solution method is proposed to reduce the computational burden. This paper proposes a two-stage data-driven unit commitment dispatching scheme, which coordinates the multi-function demand response of commercial air conditioning aggregators with thermal units to encounter the variations of load and wind power. In the proposed dispatching scheme, the flexible ramping capability of the thermal units is reflected in the coupling constraints between the ramping capacity and reserve capacity. To improve the flexibility of the whole system, multi-function demand response of commercial air conditioning aggregators is incorporated into the scheduling in both stages. In the day-ahead stage, load-shifting demand response reduces the ramping requirements by reshaping the load profile. In the real-time stage, reserve-capacity demand response releases the ramping capability by providing reserve for the rebalance of wind power fluctuation, which is represented by a data-driven uncertainty set. Since the dispatching scheme is formulated as a min–max-min problem, an accelerating solution method is developed to improve the computational efficiency, which combines the column-and-constraints generation algorithm and the specific property of the model. The simulation results tested on the modified IEEE 118-bus system and Henan power grid in China validate the effectiveness of the dispatching scheme and solution method in increasing flexible ramping capability, reducing wind power curtailment and load shedding, improving economic efficiency, and accelerating computation. [ABSTRACT FROM AUTHOR]