It has been a focus to reduce the energy consumption and improve the space heating performance of high-altitude buildings in winter seasons. In view of the abundant solar energy resources of the high-altitude region, ...It has been a focus to reduce the energy consumption and improve the space heating performance of high-altitude buildings in winter seasons. In view of the abundant solar energy resources of the high-altitude region, the establishment of passive solar houses should be an effective strategy to deal with the problem of thermal comfort. Both window to wall ratio(WWR) and sunspace depth are of vital importance to determine the thermal comfort level of passive solar houses, while there are limited studies on analyzing their impacts on passive solar houses in high-altitude regions. Therefore, this study is designed to examine how WWR and sunspace depth affect space heating of passive solar houses in the Qinghai-Tibetan region. To be specific, the hourly radiation temperature variations and percentages of dissatisfaction of the residential building with different sunspace depth/WWR(including 0.9 m/33%, 0.9 m/45%, 0.9 m/60%, 1.2 m/33% and 1.5 m/33%) were quantitatively examined. Results indicated that under the condition of 0.9 m/45%, the overall average radiation temperature of the building was approximately 16°C during the entire heating season, which could better satisfy the heating requirements. Meanwhile, the average temperature was higher, and the thermal comfort level was better under the ratio of 45% or the depth of 1.5 m, when only an individual factor in either ratio or depth was considered. These findings can provide references for the determination of dimensions of passive solar houses in high-altitude regions.展开更多
Based on κ-ε turbulence model, the distributions of the velocity field, tempera- ture field, thermal comfort index, PMV-PPD （Predicted Mean Vote-Predicted Percentage Dissatisfied）, and air quality index, mean age ...Based on κ-ε turbulence model, the distributions of the velocity field, tempera- ture field, thermal comfort index, PMV-PPD （Predicted Mean Vote-Predicted Percentage Dissatisfied）, and air quality index, mean age of air were obtained of Zhouyuanshan Coal Mine in -650 m level of a heading face by CFD（Computational Fluid Dynamics）software, Airpak 2.0. Moreover, the human thermal comfort and the air quality of the heading face were analyzed with PMV-PPD and mean age of air indices, which received an intuitive visualization and accurate evaluation results. In order to create a safe, comfortable, and economical underground operating environment, a scientific, rational, and comprehensive prediction and evaluation needed to provide a theoretical and technical basis for coal mine ventilation, cooling, heat harm treatment, and prevention. Meanwhile, from the human thermal comfort and air quality to research the underground environment, it embodied the concept of being human oriented.展开更多
The purpose of this study was to examine the prevalence of body shape dissatisfaction, weight and physical activity status among university students and predictors for body shape dissatisfaction. A cross sectional stu...The purpose of this study was to examine the prevalence of body shape dissatisfaction, weight and physical activity status among university students and predictors for body shape dissatisfaction. A cross sectional study was carried out in a sample comprising of 368 female and male university students aged 18 years or more at King Faisal University, Saudi Arabia. Body weight, height, Body Shape Questionnaire (BSQ) and physical activity level were used as assessment tools. Chi-square and independent sample T-test were used to assess gender difference. Linear regression analysis was conducted to examine predictors of the body shape dissatisfaction. Overall, 65% of students had normal BMI, more males then females overweight (23%), while more females underweight (16.8%). Females have higher body shape dissatisfaction (33.5%) then males (21.4%), half of males inactive and this percentage increased in females to (73.8%). Overweight males were more dissatisfied with their body shape (10.7%) than females (6.3%). Almost one fifth of inactive males dissatisfied comparable to quarter inactive females dissatisfied with their body shape. Younger age is predictor for body shape dissatisfaction in both genders, also weight in males. BMI and being married female was predictor for body shape dissatisfaction. Collectively results indicate that body shape dissatisfaction and inactive lifestyle were prevalent among females than male’s age, weight;BMI and marital status was the most predictor for body shape dissatisfaction. However developing educational program to promote body shape satisfaction and active lifestyle will be very useful especially among females.展开更多
To identify human thermal comfort in naturally ventilated buildings,the research based on both subjective and objective data was carried out in Chongqing,P. R. China. The characteristics of subjects' clothing regu...To identify human thermal comfort in naturally ventilated buildings,the research based on both subjective and objective data was carried out in Chongqing,P. R. China. The characteristics of subjects' clothing regulation function,changes of actual mean thermal comfort vote (AMV) varying with time and acceptable operative temperature in natural conditions were analyzed. In addition,the indicator actual mean vote-actual percentage dissatisfied (AMV-APD) was used to study the actual dissatisfaction with thermal environment. The results indicate that regulative ability by changing clothing under natural ventilated conditions is very significant but limited simultaneously,about 1.7 ℃ per 0.1 clo. Under naturally ventilated conditions,people may have an acceptable operative temperature of 16-28 ℃. Based on the AMV-APD,the actual minimum percentage dissatisfied can reach 4% at AMV of -0.36.展开更多
Considering the percentage of dissatisfied due to local thermal sensation(PD LTSV),a vertical air temperature difference(ΔT_(d))threshold of about 3°C was recommended in standards.However,some novel air distribu...Considering the percentage of dissatisfied due to local thermal sensation(PD LTSV),a vertical air temperature difference(ΔT_(d))threshold of about 3°C was recommended in standards.However,some novel air distribution methods might create large positive(which means the head warmer than the feet,vice versa)or negativeΔT_(d),with no suitable proved criteria to be used.In this study,sixteen subjects were seated in a climatic box placed in a climate chamber to evaluate thermal sensation and percentage of dissatisfied with negative and positiveΔT_(d) in different whole-body thermal conditions.Air temperatures were controlled independently at the upper and lower body parts,with 13 different air temperature sets combined with 22°C,25°C,28°C,and 31°C(i.e.-9°C≤ΔT_(d)≤9°C).Results showed that subjects were more thermally sensitive at the upper body and with positiveΔT_(d) than at the lower body or with negativeΔT_(d).The 80%acceptableΔT_(d) range is about-8 to 7°C in overall neutral(TSV=0),-7°C to 6°C in slightly cool(TSV=-0.5)conditions,which is wider than-3 to 3°C in slightly warm conditions(TSV=+0.5).By considering the factors of both TSV andΔT_(d),a new overall percentage of dissatisfied index(OPD P)was proposed.Case studies show that the new OPD P index is more precise and suitable for the evaluations of different air distributions to predict overall percentage of dissatisfied in thermal environments with vertical air temperature difference.展开更多
基金supported by National Key R&D Program of China-Technical System and Key Technology Development of Nearly Zero Energy Building (No. 2017YFC0702600)the opening Funds of State Key Laboratory of Building Safety and Built Environment National Engineering Research Center of Building Technology (BSBE2017-08)+1 种基金the Major Basic Research Development and Transformation Program of Qinghai province (No. 2016-NN-141 )the Fundamental Research Funds for the Central Universities (No. 2018MS103, 2018MS108 and 2017MS119 )
文摘It has been a focus to reduce the energy consumption and improve the space heating performance of high-altitude buildings in winter seasons. In view of the abundant solar energy resources of the high-altitude region, the establishment of passive solar houses should be an effective strategy to deal with the problem of thermal comfort. Both window to wall ratio(WWR) and sunspace depth are of vital importance to determine the thermal comfort level of passive solar houses, while there are limited studies on analyzing their impacts on passive solar houses in high-altitude regions. Therefore, this study is designed to examine how WWR and sunspace depth affect space heating of passive solar houses in the Qinghai-Tibetan region. To be specific, the hourly radiation temperature variations and percentages of dissatisfaction of the residential building with different sunspace depth/WWR(including 0.9 m/33%, 0.9 m/45%, 0.9 m/60%, 1.2 m/33% and 1.5 m/33%) were quantitatively examined. Results indicated that under the condition of 0.9 m/45%, the overall average radiation temperature of the building was approximately 16°C during the entire heating season, which could better satisfy the heating requirements. Meanwhile, the average temperature was higher, and the thermal comfort level was better under the ratio of 45% or the depth of 1.5 m, when only an individual factor in either ratio or depth was considered. These findings can provide references for the determination of dimensions of passive solar houses in high-altitude regions.
基金Supported by the National Science Foundation of China(50974059)the State Administration of Safety(05-296)
文摘Based on κ-ε turbulence model, the distributions of the velocity field, tempera- ture field, thermal comfort index, PMV-PPD （Predicted Mean Vote-Predicted Percentage Dissatisfied）, and air quality index, mean age of air were obtained of Zhouyuanshan Coal Mine in -650 m level of a heading face by CFD（Computational Fluid Dynamics）software, Airpak 2.0. Moreover, the human thermal comfort and the air quality of the heading face were analyzed with PMV-PPD and mean age of air indices, which received an intuitive visualization and accurate evaluation results. In order to create a safe, comfortable, and economical underground operating environment, a scientific, rational, and comprehensive prediction and evaluation needed to provide a theoretical and technical basis for coal mine ventilation, cooling, heat harm treatment, and prevention. Meanwhile, from the human thermal comfort and air quality to research the underground environment, it embodied the concept of being human oriented.
文摘The purpose of this study was to examine the prevalence of body shape dissatisfaction, weight and physical activity status among university students and predictors for body shape dissatisfaction. A cross sectional study was carried out in a sample comprising of 368 female and male university students aged 18 years or more at King Faisal University, Saudi Arabia. Body weight, height, Body Shape Questionnaire (BSQ) and physical activity level were used as assessment tools. Chi-square and independent sample T-test were used to assess gender difference. Linear regression analysis was conducted to examine predictors of the body shape dissatisfaction. Overall, 65% of students had normal BMI, more males then females overweight (23%), while more females underweight (16.8%). Females have higher body shape dissatisfaction (33.5%) then males (21.4%), half of males inactive and this percentage increased in females to (73.8%). Overweight males were more dissatisfied with their body shape (10.7%) than females (6.3%). Almost one fifth of inactive males dissatisfied comparable to quarter inactive females dissatisfied with their body shape. Younger age is predictor for body shape dissatisfaction in both genders, also weight in males. BMI and being married female was predictor for body shape dissatisfaction. Collectively results indicate that body shape dissatisfaction and inactive lifestyle were prevalent among females than male’s age, weight;BMI and marital status was the most predictor for body shape dissatisfaction. However developing educational program to promote body shape satisfaction and active lifestyle will be very useful especially among females.
基金Projects(50838009, 50678179) supported by the National Natural Science Foundation of ChinaProjects(2006BAJ02A09, 2006BAJ02A13-4) supported by the National Key Technologies R & D Program of ChinaProject(200909A1001) supported by Chongqing University Postgraduates’ Innovative Team Building Project
文摘To identify human thermal comfort in naturally ventilated buildings,the research based on both subjective and objective data was carried out in Chongqing,P. R. China. The characteristics of subjects' clothing regulation function,changes of actual mean thermal comfort vote (AMV) varying with time and acceptable operative temperature in natural conditions were analyzed. In addition,the indicator actual mean vote-actual percentage dissatisfied (AMV-APD) was used to study the actual dissatisfaction with thermal environment. The results indicate that regulative ability by changing clothing under natural ventilated conditions is very significant but limited simultaneously,about 1.7 ℃ per 0.1 clo. Under naturally ventilated conditions,people may have an acceptable operative temperature of 16-28 ℃. Based on the AMV-APD,the actual minimum percentage dissatisfied can reach 4% at AMV of -0.36.
基金The work presented in this paper is financially supported by the Fundamental Research Funds for the Central Universities(Grant No.2019CDYGYB026)。
文摘Considering the percentage of dissatisfied due to local thermal sensation(PD LTSV),a vertical air temperature difference(ΔT_(d))threshold of about 3°C was recommended in standards.However,some novel air distribution methods might create large positive(which means the head warmer than the feet,vice versa)or negativeΔT_(d),with no suitable proved criteria to be used.In this study,sixteen subjects were seated in a climatic box placed in a climate chamber to evaluate thermal sensation and percentage of dissatisfied with negative and positiveΔT_(d) in different whole-body thermal conditions.Air temperatures were controlled independently at the upper and lower body parts,with 13 different air temperature sets combined with 22°C,25°C,28°C,and 31°C(i.e.-9°C≤ΔT_(d)≤9°C).Results showed that subjects were more thermally sensitive at the upper body and with positiveΔT_(d) than at the lower body or with negativeΔT_(d).The 80%acceptableΔT_(d) range is about-8 to 7°C in overall neutral(TSV=0),-7°C to 6°C in slightly cool(TSV=-0.5)conditions,which is wider than-3 to 3°C in slightly warm conditions(TSV=+0.5).By considering the factors of both TSV andΔT_(d),a new overall percentage of dissatisfied index(OPD P)was proposed.Case studies show that the new OPD P index is more precise and suitable for the evaluations of different air distributions to predict overall percentage of dissatisfied in thermal environments with vertical air temperature difference.
