China has a diversity of climates and a unique historic national heating policy which greatly affects indoor thermal environment and the occupants' thermal response. This paper analyzes quantitatively the data from a large-scale field study across the country conducted from 2008 to 2011 in residential buildings. The study covers nine typical cities located in the five climate zones including Severe Cold (SC), Cold (C), Hot Summer and Cold Winter (HSCW), Hot Summer and Warm Winter (HSWW) and Mild (M) zones. It is revealed that there exists a large regional discrepancy in indoor thermal environment, the worst performing region being the HSCW zone. Different graphic comfort zones with acceptable range of temperature and humidity for the five climate zones are obtained using the adaptive Predictive Mean Vote (aPMV) model. The results show that occupants living in the poorer thermal environments in the HSCW and HSWW zones are more adaptive and tolerant to poor indoor conditions than those living in the north part of China where central heating systems are in use. It is therefore recommended to develop regional evaluation standards of thermal environments responding to climate characteristics as well as local occupants' acclimatization and adaptation in order to meeting dual targets of energy conservation and indoor thermal environment improvement.
R. (2018) A modified method of evaluating the impact of air humidity on human acceptable air temperatures in hothumid environments. Energy and Buildings, 158. pp. 393405. ISSN 03787788 Abstract: This research aims to investigate human thermal responses to air humidity in warm and hot environments and to evaluate the effect of humidity on human thermal comfort. 20 subjects were involved in 12 exposure experiments in a well-controlled climate chamber at three relative humidity levels (40%RH, 60%RH, 80%RH) and four air temperature levels (26°C, 28°C, 30°C, 32°C) with no much indoor airflow. The physical environmental and physiological parameters as well as subjective questionnaires were collected simultaneously during the period of experiments. The results show that in hot environments, particularly when the air temperature exceeds 30°C, the relative humidity has a significant effect on human thermal responses both physiologically and subjectively. The Standard Effective Temperature (SET) is biased when evaluating human thermal comfort in the hot-humid environments without considering human thermal adaptation to humidity. Hence, a humidity correction coefficient eRH is proposed to modify the deviation of the SET under different relative humidity levels, and to quantify the effect of humidity on human acceptable air temperatures. The modified acceptable temperature-humidity zone has been obtained using the modified method.
The increased demand for improving indoor thermal environment in the hot summer and cold winter climate zone (HSCW) in the Yangtze River region in China poses enormous challenges in terms of energy policy and design solutions for this unique region. A comprehensive understanding of people's habits and behaviors involving winter heating is imperative for decision making for urban heating infrastructure investment strategies that significantly impact on the decarbonization of heating. However, there has been little knowledge gained from large-scale studies in this region. The aim of this study is to develop a rigorous survey method in order to obtain reliable data for analysis. Five municipal/capital cities across the upper, middle and downstream Yangtze River are surveyed based on 30 randomly generated locations in each city. A total of 8,471 valuable samples were obtained in the survey conducted in the winter from November 2017 to March 2018. It is revealed that air conditioning/air source heat pumps are the predominant systems, accounting for 63% and 58% for bedroom and living room heating respectively.The use patterns of heating are diverse featuring 'part-time-part-space' systems in accordance with the occupancy patterns. There is significant evidence of the habit of opening a window to provide a gap for fresh air irrespective of whether the heating is in use. Two-step cluster analysis is employed to subdivide occupants' heating-related behaviors into three clusters to characterize households. This study fills the knowledge gap of winter-heating-related behaviors. The research outcomes will benefit building energy simulations for energy prediction and help policy makers make decisions on providing strategic guidance in terms of winter heating solutions in this region.
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