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Ultra-low-energy buildings in China are still in the early stage of development. In the guide documents of the 13th plan of five-year national development published by Science and Technology Ministry, an energy consumption limit of 15kWh/m2 for heating, cooling and ventilation throughout the year was pointed out for residential buildings in hot summer and cold winter region. In this paper, current situation of winter heating in Shanghai was investigated, including analysis of heating energy consumption of more than 40,000 households, a large number of questionnaires about heating status, and the actual indoor heating environment monitoring. This paper also investigated the indoor ventilation environment under real living conditions, taking a typical residence in Shanghai as the research subject via continuous field measurements. The indoor CO2 concentration, air temperature and relative humidity were monitored and two behavior-related parameters, the electricity consumption of air conditioner and the open/closed state of the window/door were recorded from summer to spring. Based on the investigation, the questionnaires and the monitored data for winter heating, heating strategies in winter for residential buildings in Shanghai will be discussed, from the perspective of gap analysis. [ABSTRACT FROM AUTHOR]

• Ventilation rate and arrangement are crucial to prevent airborne disease in healthcare facilities. • Local ventilation is practical for supply fresh air and diluting contaminants in high-risk areas. • Microplastics emerged as potential virus carriers in indoor environments, warrant further investigations. The prevalence and transmission of airborne infections pose significant challenges to public health, leading to consequential negative impacts. Ventilation strategies are crucial in mitigating airborne infections in healthcare settings, preventing the spread of infectious diseases, thus protecting patients and healthcare workers. While individual studies have explored various aspects of ventilation in healthcare settings, a synthesized overview of the current state of knowledge is lacking. Therefore, this study attempts to bridge the gap by conducting a review and bibliometric analysis based on 198 papers published within the recent decades (1993–2022). The findings will provide a holistic understanding on the innovative interventions and identify areas for future research, thereby contributing to the development of effective guidelines for controlling airborne infections. The co-authorship analysis revealed that China emerged as the main contributor in the current research field due to the keen interest of researchers and the substantial financial support provided by funding agencies. The keyword co-occurrence analysis identified three primary research hotspots within the field, (i) the optimized ventilation strategies for combating airborne infection, (ii) the transition towards the application of computational fluid dynamics (CFD) in analyzing airflow patterns, and, (iii) the characteristics of airborne particles and their impact on infection transmission. The present review highlights the significance of local ventilation as an additional measure to the main ventilation system for enhanced dilution of contaminants in high-risk areas. The transition towards dynamic airflow analysis considered human movement's effect, allowing for more precise assessments and tailored ventilation strategies optimization. The review also underscores the emerging concern of microplastic as an indoor contaminant with potential implications as a virus carrier, emphasizing further research on its behavior and impact on airborne infection transmission. [ABSTRACT FROM AUTHOR]

Abstract Air pollution is widely believed to cause healthy risks and influence nations' economic dimensions. This paper investigates the impact of air pollution on housing prices in China's 286 prefectural-level cities during 2005–2013. To address the endogeneity problem of PM 2.5 concentrations in our regression, we propose an instrument variable strategy based on ventilation coefficient. The estimation results suggest that a 10% increase in PM 2.5 concentrations causes a 2.4% reduction in local housing prices. Air pollution also hinders the progress of urbanization, limits cities' human capital formation and changes people's expectations of housing prices that we interpret as three potential mechanisms behind our main findings. [ABSTRACT FROM AUTHOR]

Abstract: By means of computational fluid dynamic (CFD) simulations, this paper investigated how rural winds transport relatively clean air into high-rise urban areas to dilute airborne pollutants. Two ventilation concepts for indoor environments were applied: the age of air to quantify the time taken by rural young air to reach a given place after it enters an urban area and the air exchange efficiency to evaluate the efficiency of rural winds flushing the entire urban canopy layer. Several square building arrays with street aspect ratios (building height/street width, H/W) ranging from 1.5 to 5.3 and building area densities of 0.25 (medium) or 0.4 (compact) were considered as the approaching wind is parallel to the main street whose length varies from street scales to neighborhood scales (330–510 m to 1.03–1.65 km in full-scale). Results show that considerable young rural air enters windward entries but a major fraction of air is vertically driven out as flowing deeper into such high-rise building arrays. So air exchange efficiencies are less than 50% in street-scale arrays, and smaller in longer (neighborhood-scale) or narrower arrays. For the neighborhood-scale medium arrays, considering the power-law velocity profile in the upstream free flow, a taller array gains a larger inflow rate across its windward entry and experiences younger air and greater air exchange efficiency than a lower one. If all buildings are theoretically open-based in a neighborhood-scale compact array, air becomes much younger everywhere and the air exchange efficiency doubles. In arrays of buildings with different heights, the secondary streets in front of taller buildings get younger air due to the downward flows within them. Although further investigations are still required before providing a practical framework, this paper is one of the first attempts to find ways in improving the ventilation performance in high-rise cities like Hong Kong. [Copyright &y& Elsevier]

Abstract: An extended Gebhart–Block model for large space buildings is proposed in this paper, which is used to predict the vertical temperature distribution of hybrid ventilation. Natural ventilation coupled with air-conditioning is described with a mathematical model. The indoor thermal environment formed by the air-conditioning and the natural ventilation can also be conducted for the potential analysis and optimal use of the natural ventilation. Experiments were carried out in an atrium building in Shanghai Research Institute of Building Sciences. This paper describes aforementioned model, and it is found that the calculation results implying this model agree well with the measurement data. [Copyright &y& Elsevier]

Song-Qing Stadium is one of the traditional buildings, and it is still in operation for Wuhan University. However, its fluid mechanical characteristic of natural ventilation has not been yet raised with any concerns. Application potentials of natural ventilation across this traditional building should be discovered. In this paper, Songqing Stadium with multiple windows is considered to investigate the wind-driven ventilation flows using computational fluid dynamics (CFD). The standard k – ε turbulence model is adopted to simulate the flow fields inside and outside the building after the procedure has been validated well by former wind tunnel experimental results. Several cases with different numbers of openings are subsequently simulated, and the effects of the location and number of openings on the stadium air movement have been investigated. Numerical results indicate that the wind pressure distributions around and inside the building are almost unchangeable in the several representative cases. The magnitude of velocity components inside and around the building are larger in cross ventilation than that in single-sided ventilation. In cross ventilation condition, the pressure coefficient on the front wall is the largest in cross ventilation with apertures opened on both sides. Pressure coefficients on the windward wall increase with numbers of lateral openings. The velocity component V outside the stadium is very weak such that it could be neglected, whereas it is relatively strong inside the stadium because the pressure in the building is not uniform across the lateral direction. When lateral openings exist, volume flow rate increases and the openings on the leeward wall could entrain ambient air though the windward apertures are opened. Nevertheless, the lateral openings do not cause the increase of the magnitude of V. The present work helps architectures and engineers to understand the characteristics of natural ventilation in the traditional public buildings, and it provides theoretical approach for developing zero-energy buildings in the future. [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]

The cause of urban heat island effect is closely related to urban activities, urban construction environment and landscape. The planning of urban ventilation corridor in Urban New District focuses on the optimization of the wind environment, not only can effectively improve the quality of living environment, but also can conducive to the realization of energy-saving emission reduction. According to the urban wind air flow movement and urban underlying surface characteristics, the paper takes Xixian New Area as an example, according to the climate in cold regions divided different ecological and climatic zoning, uses CFD simulation method, and determines the city through the main control factors of the location and number of wind corridor, purporting and corridor on the windward side of density control in urban ecology and open space layout, in order to providing a reference for future planning and construction has a good climate and environment in new city. [ABSTRACT FROM AUTHOR]

The use of natural ventilation in buildings to reduce the energy consumption and CO 2 emission has been widely investigated and practiced, but few existing studies have considered the exploration and assessment of natural ventilation in different location patterns of rural residential buildings in the mountainous terrain of China. In this paper, the representative rural residential buildings are firstly selected in Huarong, Pingjiang and Liuyang regions of northern Hunan Province to carry out on-site survey works to determine building types, physical parameters and layout forms. Then, the wind tunnel experiments are carried out to investigate the effectiveness of natural ventilation under different location patterns, and the monitored results are compared with simulated data. The results show that the experiments and simulations are in satisfactory agreement. The experimental data also indicate that when the modelled distance of 120 mm (i.e. 12 m between the building and hilly terrain in practical application) is the best option for building natural ventilation. Based on the investigation and statistical data, the natural ventilation effectiveness under different location patterns and operational conditions is simulated using CFD methods, and it is obtained the most favourable location pattern for natural ventilation. The results show that the winter ventilation of buildings in the existing location pattern is significantly obstructed in the hilly terrain, which is favourable to the indoor thermal environment, however, the natural ventilation is compromised to a certain extent in summer. Furthermore, the findings also show that, regardless of the hilly terrain's height at 50 m or 150 m, the buildings are able to avoid natural ventilation in winter to the maximum extent when the distance between the buildings and the frontier of the hilly terrain is double that of the building height (i.e. 12 m). This study could contribute to theoretical instructions for optimum design of natural ventilation of rural residential buildings in the mountainous terrain of central China. [ABSTRACT FROM AUTHOR]

Abstract: The engineering background of this paper is the upper protecting seams exploitation of Huangsha Mine, By use of CFD software to analyze the methane delivery law in U type ventilation work face gob. By analyzing the density distribution, pressure distribution, velocity field and mash methane concentration of air-methane mixed gas, obtained the locations of gas drainage hole, and summed up the methane delivery law in U type ventilation work face gob. [Copyright &y& Elsevier]

Abstract: Urban heat island can significantly increase the demand for cooling of buildings in cities. This paper investigates one of the main causes of the urban heat island phenomenon, i.e. reduced city ventilation. Two simple Hong Kong city models with relatively complex terrain were considered here under different atmospheric conditions. A 3D RNG k–ɛ turbulence model was used for modeling turbulence effects. The simulation results showed that the influence of thermal stratification can be significant on city ventilation driven partially by thermal buoyancy. When the wind speed is relatively large, the impact of thermal stratification on air flow in city street canyons is minor. When the wind speed is small relative to the buoyancy force, the airflow in the street canyons is dependent on thermal stratification. When there is an adverse vertical temperature gradient, the greater the instability, the stronger the vertical mixing and the greater the flow rate caused by turbulence. The heat and pollutants can easily accumulate under stable atmospheric conditions when there is only a weak background wind or none at all. [Copyright &y& Elsevier]

Abstract: Energy consumption is an important issue in China. In heating, ventilation and air conditioning (HVAC) systems, more and more commercial buildings use air-to-air heat recovery ventilators as energy saving units for recovering heat from the exhaust air in ventilation systems in current years. In the present paper, critical temperatures of air-to-air heat recovery systems for supermarkets in winter are recommended and discussed for the four cities in different climate zones of China. The analysis shows that the temperature of fresh air in winter can be categorized into three regions, i.e., recovery region, transition region and impermissible recovery region. The results also indicate that the latent heat recovery is not suitable for ventilation energy savings in supermarkets in winter. Meanwhile, the applicability of sensible heat recovery in supermarkets depends on outdoor climate and fresh air flow rate. If a variable rotational speed fan is used to introduce fresh air into the building, heat recovery does always function as planned in winter for all the selected cities except Guangzhou, and most values of the COP are much higher than 2.5. Otherwise, there is the risk of negative impact on building energy savings in all cities except Harbin. [ABSTRACT FROM AUTHOR]

Thermal comfort evaluations in the built environment are essential to occupant's satisfaction and also building energy consumption. Traditionally, thermal comfort has been assessed by Fanger's PMV model that was developed based on extensive laboratory tests. However, it's been found that PMV predictions are not good in field studies, especially in buildings with natural ventilation. In this paper, machine learning (ML) algorithms were used to predicted occupants' thermal comfort votes (TCV) and thermal sensation votes (TSV), using 5512 sets of thermal comfort data collected in naturally ventilated residential buildings in fourteen cities in China. Environmental parameters, personal parameters, climatic types, and adaptive control measures were considered and used as input parameters for the ML model. It was found that environmental parameters (both outdoors and indoors), personal parameters (metabolic rate and clothing insulation), and climatic types all significant affect both TCV and TSV, while adaptive control measures only affect TSV but not TCV. Comparing with established models (PMV, ePMV and aPMV), the ML models had smaller errors in predicting TSV and TCV. Based on these results, we suggest that the ML, especially ANNs model was reliable in predicting occupants' TCV and TSV in naturally ventilated residential buildings, and performed better than traditional thermal balance based models. Moreover, using the new model, we found that acceptable temperature ranges in naturally ventilated buildings were far wider than the ASHRAE adaptive comfort zone, suggesting that appropriate models should be established based on local data. [ABSTRACT FROM AUTHOR]