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To evaluate the separate impacts on human health and establish effective control strategies, it is crucial to estimate the contribution of outdoor infiltration and indoor emission to indoor PM2.5 in buildings. This study used an algorithm to automatically estimate the long-term time-resolved indoor PM2.5 of outdoor and indoor origin in real apartments with natural ventilation. The inputs for the algorithm were only the time-resolved indoor/outdoor PM2.5 concentrations and occupants’ window actions, which were easily obtained from the low-cost sensors. This study first applied the algorithm in an apartment in Tianjin, China. The indoor/outdoor contribution to the gross indoor exposure and time-resolved infiltration factor were automatically estimated using the algorithm. The influence of outdoor PM2.5 data source and algorithm parameters on the estimated results was analyzed. The algorithm was then applied in four other apartments located in Chongqing, Shenyang, Xi'an, and Urumqi to further demonstrate its feasibility. The results provided indirect evidence, such as the plausible explanations for seasonal and spatial variation, to partially support the success of the algorithm used in real apartments. Through the analysis, this study also identified several further development directions to facilitate the practical applications of the algorithm, such as robust long-term outdoor PM2.5 monitoring using low-cost light-scattering sensors.
Tongling Xia; Yue Qi; Xilei Dai; Jinyu Liu; Can Xiao; Ruoyu You; Dayi Lai; Junjie Liu; Chun Chen. Estimating long‐term time‐resolved indoor PM 2.5 of outdoor and indoor origin using easily obtainable inputs. Indoor Air 2021, 1 .
AMA StyleTongling Xia, Yue Qi, Xilei Dai, Jinyu Liu, Can Xiao, Ruoyu You, Dayi Lai, Junjie Liu, Chun Chen. Estimating long‐term time‐resolved indoor PM 2.5 of outdoor and indoor origin using easily obtainable inputs. Indoor Air. 2021; ():1.
Chicago/Turabian StyleTongling Xia; Yue Qi; Xilei Dai; Jinyu Liu; Can Xiao; Ruoyu You; Dayi Lai; Junjie Liu; Chun Chen. 2021. "Estimating long‐term time‐resolved indoor PM 2.5 of outdoor and indoor origin using easily obtainable inputs." Indoor Air , no. : 1.
Following advancement in urbanization, outdoor thermal comfort is receiving increasing attention, with radiation being an influencing factor. To determine the shading preference, instead of a subjective questionnaire survey, an objective foot vote approach was proposed using remote sensing images. Subsequently, the meteorological data of cities were obtained from the Bureau of Meteorology. From the results, the foot vote was approximately consistent with the PMV, and pedestrians tended to move to the shaded area if it was hot and to the non-shaded area if it was cold. However, people do not move if the foot vote value ranges from 1 to 2, and the thermal acceptance range of PET is 19.2–29 °C in Beijing when using the definitions of foot vote. The outdoor thermal acceptance differs significantly with the types of outdoor sites and climates, and pedestrians in Beijing are significantly more sensitive than those in Wuhan if the outdoor thermal environment changes. Compared to transportation hubs and shopping malls, pedestrians in public buildings are less sensitive, whereas those in scenic spots are more sensitive. Results from this study will be beneficial to policymakers in urban designing to renovate and improve thermally comfortable urban environments at the pedestrian level.
Peng Xue; Xiaoyu Jia; Dayi Lai; Xiaojing Zhang; Cheng Fan; Weirong Zhang; Nan Zhang. Investigation of outdoor pedestrian shading preference under several thermal environment using remote sensing images. Building and Environment 2021, 200, 107934 .
AMA StylePeng Xue, Xiaoyu Jia, Dayi Lai, Xiaojing Zhang, Cheng Fan, Weirong Zhang, Nan Zhang. Investigation of outdoor pedestrian shading preference under several thermal environment using remote sensing images. Building and Environment. 2021; 200 ():107934.
Chicago/Turabian StylePeng Xue; Xiaoyu Jia; Dayi Lai; Xiaojing Zhang; Cheng Fan; Weirong Zhang; Nan Zhang. 2021. "Investigation of outdoor pedestrian shading preference under several thermal environment using remote sensing images." Building and Environment 200, no. : 107934.
Thermal sensation models are commonly used to assess thermal perception in various indoor environments. Our previous work developed a new model to predict thermal sensation in cars that uses gradual change in thermal load on the face, sudden change in solar radiation on the face, mean skin temperature and outdoor air temperature as predictors. The present investigation selected 11 outdoor scenarios and 20 indoor scenarios from the literature to further verify the accuracy of the thermal sensation model. Four other thermal models, the predicted mean vote (PMV) model, the dynamic thermal sensation (DTS) model, a model from the University of California, Berkeley (UCB), and a transient outdoor thermal comfort model (Lai's) were compared with the new model for the 32 scenarios. The results confirmed the validity of the new model in an outdoor environment with sudden change in solar radiation. The new model was able to predict the trend of thermal changes, but the accuracy was not as good as that of the PMV model in an environment with indoor temperature gradient/sudden changes.
Xiaojie Zhou; Dayi Lai; Qingyan Chen. Evaluation of thermal sensation models for predicting thermal comfort in dynamic outdoor and indoor environments. Energy and Buildings 2021, 238, 110847 .
AMA StyleXiaojie Zhou, Dayi Lai, Qingyan Chen. Evaluation of thermal sensation models for predicting thermal comfort in dynamic outdoor and indoor environments. Energy and Buildings. 2021; 238 ():110847.
Chicago/Turabian StyleXiaojie Zhou; Dayi Lai; Qingyan Chen. 2021. "Evaluation of thermal sensation models for predicting thermal comfort in dynamic outdoor and indoor environments." Energy and Buildings 238, no. : 110847.
The indoor environment influences occupants’ health. From March 1, 2018, to February 28, 2019, we continuously monitored indoor temperature (T), relative humidity (RH), and CO2 concentration in bedrooms via an online system in 165 residences that covered all five climate zones of China. Meanwhile, we asked one specific occupant in each home to complete questionnaires about perceived air quality and sick building syndrome (SBS) symptoms at the end of each month. Higher CO2 concentration was significantly associated with a higher percentage of perceived stuffy odor and skin SBS symptoms. Higher relative humidity was associated with higher percentage of perceived moldy odor and humid air, while lower RH was associated with a higher percentage of perceived dry air. Occupants who lived in residences with high RH were less likely to have mucosal and skin SBS symptoms (adjusted odds ratio (AOR): 0.73–0.78). However, the benefit of high humidity for perceived dry air and skin dryness symptoms is weaker if there is a high CO2 concentration level.
Jing Hou; YueXia Sun; Xilei Dai; Junjie Liu; Xiong Shen; Hongwei Tan; Haiguo Yin; Kailiang Huang; Yao Gao; Dayi Lai; Weiping Hong; Xinping Zhai; Dan Norbäck; Qingyan Chen. Associations of indoor carbon dioxide concentrations, air temperature, and humidity with perceived air quality and sick building syndrome symptoms in Chinese homes. Indoor Air 2021, 31, 1018 -1028.
AMA StyleJing Hou, YueXia Sun, Xilei Dai, Junjie Liu, Xiong Shen, Hongwei Tan, Haiguo Yin, Kailiang Huang, Yao Gao, Dayi Lai, Weiping Hong, Xinping Zhai, Dan Norbäck, Qingyan Chen. Associations of indoor carbon dioxide concentrations, air temperature, and humidity with perceived air quality and sick building syndrome symptoms in Chinese homes. Indoor Air. 2021; 31 (4):1018-1028.
Chicago/Turabian StyleJing Hou; YueXia Sun; Xilei Dai; Junjie Liu; Xiong Shen; Hongwei Tan; Haiguo Yin; Kailiang Huang; Yao Gao; Dayi Lai; Weiping Hong; Xinping Zhai; Dan Norbäck; Qingyan Chen. 2021. "Associations of indoor carbon dioxide concentrations, air temperature, and humidity with perceived air quality and sick building syndrome symptoms in Chinese homes." Indoor Air 31, no. 4: 1018-1028.
Sleep thermal environments substantially impact sleep quality. To study the sleep thermal environment and thermal comfort in China, this study carried out on‐site monitoring of thermal environmental parameters in peoples’ homes, including 166 households in five climate zones, for one year. A questionnaire survey on sleep thermal comfort and adaptive behavior was also conducted. The results showed that the indoor temperature for sleep in northern China was more than 4°C higher than that in southern China in winter, while the indoor temperatures for sleep were similar in summer. Furthermore, 70% of people were satisfied with their sleep thermal environment. Due to the use of air conditioning and window opening in various areas in summer, people were satisfied with their sleep thermal environments. Due to the lack of central heating in the southern region in winter, people feel cold and their sleep thermal environment needs further improvement. The bedding insulation in summer and winter in northern China was 1.83clo and 2.67clo, respectively, and in southern China was 2.21clo and 3.17clo, respectively. Both northern China and southern China used air conditioning only in summer. People in southern China opened their windows all year, while those in northern China opened their windows during the summer and transitional periods.
Jinyu Liu; Junjie Liu; Dayi Lai; Jingjing Pei; Shen Wei. A field investigation of the thermal environment and adaptive thermal behavior in bedrooms in different climate regions in China. Indoor Air 2020, 31, 887 -898.
AMA StyleJinyu Liu, Junjie Liu, Dayi Lai, Jingjing Pei, Shen Wei. A field investigation of the thermal environment and adaptive thermal behavior in bedrooms in different climate regions in China. Indoor Air. 2020; 31 (3):887-898.
Chicago/Turabian StyleJinyu Liu; Junjie Liu; Dayi Lai; Jingjing Pei; Shen Wei. 2020. "A field investigation of the thermal environment and adaptive thermal behavior in bedrooms in different climate regions in China." Indoor Air 31, no. 3: 887-898.
Thermally comfortable outdoor spaces have contributed to high-quality urban living. In order to provide a further understanding of the influences of gender and long-term thermal history on outdoor thermal comfort, this study conducted field surveys at a university campus in Shanghai, China by carrying out microclimatic monitoring and subjective questionnaires from May to October, 2019. The analysis of collected data found that, during our survey, 57% of the occupants felt comfortable overall and 40–60% of them perceived the microclimate variables (air temperature, humidity, solar radiation, and wind speed) as “neutral”. The universal thermal climate index (UTCI) provided a better correlation with occupant thermal sensation than the physiologically equivalent temperature (PET). Females were more sensitive to the outdoor thermal environment than males. Older age led to lower thermal sensation, but the thermal sensitivities for age groups of 50 were similar. Occupants who had resided in Shanghai for a longer period showed higher overall comfort rating and lower thermal sensation. Interviewees who came from hot summer and cold winter climate regions were less effected by the change of UTCI than those from severe cold or cold climate regions.
Jiao Xue; Xiao Hu; Shu Sani; Yuanyuan Wu; Xinyu Li; Liang Chai; Dayi Lai. Outdoor Thermal Comfort at a University Campus: Studies from Personal and Long-Term Thermal History Perspectives. Sustainability 2020, 12, 9284 .
AMA StyleJiao Xue, Xiao Hu, Shu Sani, Yuanyuan Wu, Xinyu Li, Liang Chai, Dayi Lai. Outdoor Thermal Comfort at a University Campus: Studies from Personal and Long-Term Thermal History Perspectives. Sustainability. 2020; 12 (21):9284.
Chicago/Turabian StyleJiao Xue; Xiao Hu; Shu Sani; Yuanyuan Wu; Xinyu Li; Liang Chai; Dayi Lai. 2020. "Outdoor Thermal Comfort at a University Campus: Studies from Personal and Long-Term Thermal History Perspectives." Sustainability 12, no. 21: 9284.
Many of the sustainable urban development issues, such as human heath, energy consumption, carbon emission, are related to the climate of cities. As a result, research insights gained in urban climate study can be applied to improve urban sustainability. Although the Local Climate Zones (LCZ) scheme was originally proposed to provide a standardized classification of landscapes to study urban air temperature, its use was not limited to the study of urban heat islands. This study explores the applications of LCZ scheme in various research domains by conducting a bibliometric analysis in CiteSpace on over 800 articles that cites the original article of LCZ. These articles cover a wide range of research categories including meteorology, atmospheric science, environmental science, remote sensing, building technology, civil engineering, ecology, urban studies, etc. The LCZ scheme facilitates urban climate data collection by refining monitoring network, providing reasonable modelling input, and improving database documentation. In addition to the study of urban heat islands, the LCZ scheme was applied in studies of urban thermal comfort, human health, building energy consumption, and carbon emission. The diffusion of the LCZ scheme to other research domains offers an example that the development of urban climate research advances sustainable urban development. This review provides insights of multidisciplinary studies related to urban climate for policy-makers, urban specialists, architects, ecologists, and others.
Jiao Xue; Ruoyu You; Wei Liu; Chun Chen; Dayi Lai. Applications of Local Climate Zone Classification Scheme to Improve Urban Sustainability: A Bibliometric Review. Sustainability 2020, 12, 8083 .
AMA StyleJiao Xue, Ruoyu You, Wei Liu, Chun Chen, Dayi Lai. Applications of Local Climate Zone Classification Scheme to Improve Urban Sustainability: A Bibliometric Review. Sustainability. 2020; 12 (19):8083.
Chicago/Turabian StyleJiao Xue; Ruoyu You; Wei Liu; Chun Chen; Dayi Lai. 2020. "Applications of Local Climate Zone Classification Scheme to Improve Urban Sustainability: A Bibliometric Review." Sustainability 12, no. 19: 8083.
Thermal sensation in cars is different from that in buildings. Transient, asymmetric solar radiation and transient, non-uniform air temperature are the main causes of the difference. This investigation conducted human subject tests with 24 subjects, 62 trials under three outdoor driving conditions. These three driving conditions refers to 1) highly transient environments during the cool-down phases in summer, 2) highly transient environments during the warm-up in winter, and 3) sudden changes in solar radiation in shoulder season. Then the data were used to evaluate the performance of four thermal sensation models: the predicted mean vote model, the dynamic thermal sensation model, a model from the University of California, Berkeley, and a transient outdoor thermal sensation model. The results of the evaluation indicated that none of the models could accurately predict thermal sensation in a car. The sudden change in solar radiation experienced by the driver was identified as an important factor in this discrepancy. Therefore, this study proposed a new thermal sensation model that incorporates the change in the driver's thermal load caused by a sudden change in solar radiation as a predictor. This investigation verified the validity of the new model in a transient and non-uniform vehicular thermal environment.
Xiaojie Zhou; Dayi Lai; Qingyan Chen. Thermal sensation model for driver in a passenger car with changing solar radiation. Building and Environment 2020, 183, 107219 .
AMA StyleXiaojie Zhou, Dayi Lai, Qingyan Chen. Thermal sensation model for driver in a passenger car with changing solar radiation. Building and Environment. 2020; 183 ():107219.
Chicago/Turabian StyleXiaojie Zhou; Dayi Lai; Qingyan Chen. 2020. "Thermal sensation model for driver in a passenger car with changing solar radiation." Building and Environment 183, no. : 107219.
Manufacturing industries play an important role in economic development, but a large amount of energy is consumed in the removal of pollutants and heat generated on the manufacturing floor. An efficient ventilation system is needed for improving indoor air quality and thermal comfort at reduced energy cost. This study studied a displacement ventilation system with diffusers around columns for a machining plant, and compared its energy consumption with that of a perfect mixing ventilation system and the existing ventilation system in the plant. This investigation used computational fluid dynamics (CFD) to determine the vertical air temperature gradient in the plant, and the impact of temperature gradient on energy was estimated by means of building energy simulations (BES). The annual energy cost for the improved displacement ventilation system was 17.5% lower than that for mixing ventilation and 20.3% lower than for the existing ventilation system. However, because a large amount of outdoor air was used in winter, the heating energy consumption with the displacement ventilation was slightly higher than with the other two ventilation systems.
Chuanming Chen; Dayi Lai; Qingyan Chen. Energy analysis of three ventilation systems for a large machining plant. Energy and Buildings 2020, 224, 110272 .
AMA StyleChuanming Chen, Dayi Lai, Qingyan Chen. Energy analysis of three ventilation systems for a large machining plant. Energy and Buildings. 2020; 224 ():110272.
Chicago/Turabian StyleChuanming Chen; Dayi Lai; Qingyan Chen. 2020. "Energy analysis of three ventilation systems for a large machining plant." Energy and Buildings 224, no. : 110272.
Under the warming climate, providing thermal comfort to large urban population in city open spaces has become an important research topic. However, because of its dynamic and complex nature, the outdoor thermal comfort is difficult to predict. Skin temperature of human body may contain useful information of outdoor thermal comfort. In this paper, a Support Vector Machine (SVM) model was developed to predict the cool discomfort, comfort, and warm discomfort in outdoor environments using local skin temperatures and thermal load as inputs. In this study, the performances of models using different inputs were compared with each other. The results revealed that when using single local skin temperature as input, the skin temperature of exposed body parts exhibited the highest prediction accuracy (66 %–70 %), while that of abdomen or thorax was the lowest (42 %–58 %). The prediction accuracy increased by 1 %–5 % when the thermal load was added as an extra input feature, while that could be improved by 4%–7% when using skin temperature of two body parts as inputs. This study demonstrated that human outdoor thermal state can be captured with reasonable accuracy by monitoring skin temperatures from two local body parts.
Kuixing Liu; Ting Nie; Wei Liu; Yiqing Liu; Dayi Lai. A machine learning approach to predict outdoor thermal comfort using local skin temperatures. Sustainable Cities and Society 2020, 59, 102216 .
AMA StyleKuixing Liu, Ting Nie, Wei Liu, Yiqing Liu, Dayi Lai. A machine learning approach to predict outdoor thermal comfort using local skin temperatures. Sustainable Cities and Society. 2020; 59 ():102216.
Chicago/Turabian StyleKuixing Liu; Ting Nie; Wei Liu; Yiqing Liu; Dayi Lai. 2020. "A machine learning approach to predict outdoor thermal comfort using local skin temperatures." Sustainable Cities and Society 59, no. : 102216.
Machining plants are often highly polluted indoor environments with dense oil mist generated from metalworking fluids. Workers exposed to oil mist may suffer serious health problems. General ventilation is often used to dilute the oil mist level below the threshold of health risk. However, it is not easy to organize the flow for ventilating a large machining plant with hundreds of machines in order to effectively remove the oil mist. In order to develop an effective ventilation system, this study validated a computational fluid dynamics (CFD) program with the RNG k-ε model at a high Grashof number by using the measured air temperature and contaminant concentration in several locations in a high-ceiling lab with heat and pollutant sources. Next, the validated CFD program was used to develop an improved displacement ventilation system in which air is supplied from the lower parts of the support columns in the plant. With thermal plumes generated by machines and workers, the system formed unidirectional airflow that carried pollutants away from the work area of the factory. The system reduced the oil-mist concentration by more than 70% compared with existing ventilation system. In addition, suspended radiant heaters are recommended for supplemental heating in winter.
Guanqiong Wei; Bingqian Chen; Dayi Lai; Qingyan Chen. An improved displacement ventilation system for a machining plant. Atmospheric Environment 2020, 228, 117419 .
AMA StyleGuanqiong Wei, Bingqian Chen, Dayi Lai, Qingyan Chen. An improved displacement ventilation system for a machining plant. Atmospheric Environment. 2020; 228 ():117419.
Chicago/Turabian StyleGuanqiong Wei; Bingqian Chen; Dayi Lai; Qingyan Chen. 2020. "An improved displacement ventilation system for a machining plant." Atmospheric Environment 228, no. : 117419.
Thermal radiation is an important component of outdoor thermal environment since it accounts for a significant part of thermal load on human body. This study investigated the radiation fields in two outdoor spaces with different Sky View Factors (SVFs) in summer and autumn, and under sunny and overcast weather conditions. The result shows that the decrease of SVF significantly reduced the short-wave radiation due to the block of the sun. In contrast, the change in SVF had a much smaller impact on the level of long-wave radiation. The total level of radiation among seasons had a huge difference, as the difference in the Tmrt among seasons exceeded 30 °C. Weather condition had a smaller impact on the total level of radiation than season, as the Tmrt on a sunny day was only about 10 °C higher than that on an overcast day. The findings of this study provide a database for studying the radiation field and thermal comfort in outdoor spaces.
Kuixing Liu; Wenyu Liu; Tingting Gan; Dayi Lai; Gang Liu. Effects of Space Geometry, Season and Weather Condition on Different Components of Outdoor Thermal Radiation. Soil and Recycling Management in the Anthropocene Era 2020, 777 -786.
AMA StyleKuixing Liu, Wenyu Liu, Tingting Gan, Dayi Lai, Gang Liu. Effects of Space Geometry, Season and Weather Condition on Different Components of Outdoor Thermal Radiation. Soil and Recycling Management in the Anthropocene Era. 2020; ():777-786.
Chicago/Turabian StyleKuixing Liu; Wenyu Liu; Tingting Gan; Dayi Lai; Gang Liu. 2020. "Effects of Space Geometry, Season and Weather Condition on Different Components of Outdoor Thermal Radiation." Soil and Recycling Management in the Anthropocene Era , no. : 777-786.
With the increase of urban population, it is vital to create thermally comfortable outdoor open spaces. To obtain data for examining the relationship between the meteorological parameters and outdoor thermal sensation, this study conducted thermal comfort tests on 30 subjects on the campus of Tianjin University. Our results indicated that in autumn and winter, outdoor solar radiation had the greatest influence on thermal sensation, followed by air temperature, wind speed, and relative humidity. Under different combination of meteorological conditions, radiation, temperature and wind speed had different effects on thermal sensation: (1) When the radiation value was low (mean radiant flux <450 W/m2), the air temperature change from 14 to 22 °C did not affect the thermal sensation. (2) When the radiation value was high, in the high-temperature range (28–30 °C), the increase of the radiation value significantly increased the thermal sensation; (3) The cooling effect of wind speed on thermal sensation was large under high and low solar radiation. The acquired data in this study could help the design and construction of thermally comfortable urban open spaces.
Kuixing Liu; Tingting Gan; Wenyu Liu; Dayi Lai; Gang Liu. Influences of Different Meteorological Parameters on Outdoor Thermal Comfort in Cold Climate Regions in China. Soil and Recycling Management in the Anthropocene Era 2020, 725 -734.
AMA StyleKuixing Liu, Tingting Gan, Wenyu Liu, Dayi Lai, Gang Liu. Influences of Different Meteorological Parameters on Outdoor Thermal Comfort in Cold Climate Regions in China. Soil and Recycling Management in the Anthropocene Era. 2020; ():725-734.
Chicago/Turabian StyleKuixing Liu; Tingting Gan; Wenyu Liu; Dayi Lai; Gang Liu. 2020. "Influences of Different Meteorological Parameters on Outdoor Thermal Comfort in Cold Climate Regions in China." Soil and Recycling Management in the Anthropocene Era , no. : 725-734.
Indoor thermal environments in residential buildings vary due to differences in the outdoor climates, the envelope thermal properties of the buildings, the types of heating and cooling systems, and adaptive behaviors such as the operation of air conditioners and windows by dwellers. This study comprehensively investigated the thermal environments in 46 apartments in nine cities across five climate zones in China via on-site monitoring of the indoor air temperature, the relative humidity, and the air conditioner and window use for one year. The results demonstrate large variations in the thermal environments among the cities. During the heating period, the interior air in Urumqi and Shenyang was overheated (>24 °C) 43% and 59% of the time, respectively, while the indoor air temperature in Chongqing can be lower than 10 °C. As the outdoor climate became warmer, the temperature difference between indoors and outdoors decreased due to the increased window-opening duration. In summer, the indoor humidity ratio was higher than 12 g/kg for a long time in all cities except Urumqi. A clear linear positive correlation between the indoor and outdoor humidity ratios was identified until the indoor humidity reached 18 g/kg, which was due to the increased use of air conditioners. The results of this study provide an updated overall picture of the thermal environments in Chinese residential buildings.
Yue Qi; Junjie Liu; Dayi Lai; Huibo Zhang; Xiaodong Cao; Shen Wei; Hiroshi Yoshino. Large-scale and long-term monitoring of the thermal environments and adaptive behaviors in Chinese urban residential buildings. Building and Environment 2019, 168, 106524 .
AMA StyleYue Qi, Junjie Liu, Dayi Lai, Huibo Zhang, Xiaodong Cao, Shen Wei, Hiroshi Yoshino. Large-scale and long-term monitoring of the thermal environments and adaptive behaviors in Chinese urban residential buildings. Building and Environment. 2019; 168 ():106524.
Chicago/Turabian StyleYue Qi; Junjie Liu; Dayi Lai; Huibo Zhang; Xiaodong Cao; Shen Wei; Hiroshi Yoshino. 2019. "Large-scale and long-term monitoring of the thermal environments and adaptive behaviors in Chinese urban residential buildings." Building and Environment 168, no. : 106524.
Urban spaces offer considerable social, health, environmental, and economic benefits to cities and citizens. As a result, attracting more people to urban outdoor spaces is a goal of sustainable urban planning. This study conducted field surveys in a park in Tianjin, in northern China, to study the impacts of thermal comfort and life patterns on the intensity of activity in urban spaces. Analysis of the data found that subjects who engaged in intense activity were less sensitive to cold than to heat. The attendance of people with children exhibited a very high rate of decrease as the thermal environment became unfavorable. When the thermal environment changed from cold to hot, people in the park adapted by moving from open to shaded spaces. This study revealed that different activities followed distinctive patterns. Intense activity occurred mainly in the afternoon, attending to children occurred primarily in the morning, and low-intensity activity happened all day, but its occurrence decreased at noon. By incorporating the impact of thermal comfort and life patterns, this study developed a mixed-influence model to analyze the hourly usage rate in the park. The findings of this study are useful for designers seeking to create sustainable and attractive open spaces.
Dayi Lai; Bingqian Chen; Kuixing Liu. Quantification of the influence of thermal comfort and life patterns on outdoor space activities. Building Simulation 2019, 13, 113 -125.
AMA StyleDayi Lai, Bingqian Chen, Kuixing Liu. Quantification of the influence of thermal comfort and life patterns on outdoor space activities. Building Simulation. 2019; 13 (1):113-125.
Chicago/Turabian StyleDayi Lai; Bingqian Chen; Kuixing Liu. 2019. "Quantification of the influence of thermal comfort and life patterns on outdoor space activities." Building Simulation 13, no. 1: 113-125.
This study compares the linear regression model, ordered probability model, and multinomial logit model for prediction of the individual thermal sensation votes (TSVs) and TSV distributions under given conditions. Two thermal comfort datasets were used to develop and evaluate the models. One dataset was taken from an indoor thermal comfort survey conducted in Pakistan, and the other was taken from an outdoor thermal comfort survey conducted in Tianjin, China. The data were divided into training and validation datasets. The training datasets were used for model development. The developed models were then used to predict new cases in the validation dataset. The predictive capability of the three models were systematically evaluated and compared to examine how well the developed models predicted individual TSVs and TSV distributions for the validation dataset. The results showed that the ordered probability model and the multinomial logit model correctly predicted around 50% of the individual TSVs, whereas the accuracy of the linear regression model was only around 20 to 40%. In addition, the chi-square statistics show that the ordered probability model and the multinomial logit model better predicted the TSV distributions than the linear regression model.
Dayi Lai; Chun Chen. Comparison of the linear regression, multinomial logit, and ordered probability models for predicting the distribution of thermal sensation. Energy and Buildings 2019, 188-189, 269 -277.
AMA StyleDayi Lai, Chun Chen. Comparison of the linear regression, multinomial logit, and ordered probability models for predicting the distribution of thermal sensation. Energy and Buildings. 2019; 188-189 ():269-277.
Chicago/Turabian StyleDayi Lai; Chun Chen. 2019. "Comparison of the linear regression, multinomial logit, and ordered probability models for predicting the distribution of thermal sensation." Energy and Buildings 188-189, no. : 269-277.
It is essential to quickly provide an acceptable comfort level in a car by automobile manufacturers during short commutes. Many previous thermal comfort tests for passenger cars were performed in laboratories or under parking conditions, where the thermo-fluid conditions and the driver's perception of thermal comfort may not have been the same as those under outdoor driving conditions. This study conducted tests under outdoor driving conditions, measuring the outside weather conditions, the air and surface temperatures inside a car, and the skin temperatures and thermal sensation votes of the driver under summer conditions. The results show that the air and surface temperatures in the car were non-uniform and decreased rapidly in the first 15 min after the air-conditioning system was switched on. In addition, the thermal comfort conditions in the car did not reach a steady state after 2 h. Thus, a thermal comfort study in a car should be conducted under transient conditions. Reasonably good correlation existed between the mean skin temperature and mean thermal sensation. This study also found that the thermal sensation of the driver under outdoor driving conditions was different from that when the vehicle was parked.
Xiaojie Zhou; Dayi Lai; Qingyan Chen. Experimental investigation of thermal comfort in a passenger car under driving conditions. Building and Environment 2018, 149, 109 -119.
AMA StyleXiaojie Zhou, Dayi Lai, Qingyan Chen. Experimental investigation of thermal comfort in a passenger car under driving conditions. Building and Environment. 2018; 149 ():109-119.
Chicago/Turabian StyleXiaojie Zhou; Dayi Lai; Qingyan Chen. 2018. "Experimental investigation of thermal comfort in a passenger car under driving conditions." Building and Environment 149, no. : 109-119.