Predicting human thermal comfort in a transient nonuniform thermal environment

2004 ◽  
Vol 92 (6) ◽  
pp. 721-727 ◽  
Author(s):  
J. P. Rugh ◽  
R. B. Farrington ◽  
D. Bharathan ◽  
A. Vlahinos ◽  
R. Burke ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Human Thermal Comfort

scholarly journals Experimental study on dynamic thermal environment of passenger compartment based on thermal evaluation indexes

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094299
Author(s):  
Liang Zhang ◽  
Liangkui Qi ◽  
Jianhua Liu ◽  
Qingqing Wu
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Prediction Accuracy ◽  
Thermal Environment ◽  
Temperature Model ◽  
Equivalent Temperature ◽  
Vote Model ◽  
Evaluation Indexes ◽  
Human Thermal Comfort ◽  
Experimental Values

In this article, the thermal environment and the human thermal comfort of car cabin under different driving states in summer were studied experimentally. The weighted predictive mean vote model and the weighted equivalent temperature model were used for calculation and compared with the experimental values. The experimental results show that the air temperature and relative humidity distribution in cabin are affected by the space position and driving state. The temperature of the cabin seat, which is affected by solar radiation and crew, in the heating stage is slightly higher than the air temperature, while the cooling rate in the cooling stage is much lower than the air temperature. The predictive mean vote model and the equivalent temperature model are basically consistent with the actual thermal comfort of human body under the idle and driving conditions with the change of time. The prediction accuracy of the two models under the idle condition is higher than that under the driving condition, and the overall prediction accuracy of the equivalent temperature model is higher than that of the predictive mean vote model.

scholarly journals Thermal Environment of Urban Schoolyards: Current and Future Design with Respect to Children’s Thermal Comfort

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1144
Author(s):  
Dimitrios Antoniadis ◽  
Nikolaos Katsoulas ◽  
Dimitris Κ. Papanastasiou
Keyword(s):  
Heat Stress ◽  
Adverse Effects ◽  
Thermal Comfort ◽  
Vegetation Cover ◽  
Thermal Environment ◽  
Positive Impact ◽  
High Surface ◽  
Well Being ◽  
Ambient Conditions ◽  
Human Thermal Comfort

Urban outdoor thermal conditions, and its impacts on the health and well-being for the city inhabitants have reached increased attention among biometeorological studies during the last two decades. Children are considered more sensitive and vulnerable to hot ambient conditions compared to adults, and are affected strongly by their thermal environment. One of the urban outdoor environments that children spend almost one third of their school time is the schoolyard. The aims of the present manuscript were to review studies conducted worldwide, in order to present the biophysical characteristics of the typical design of the urban schoolyard. This was done to assess, in terms of bioclimatology, the interactions between the thermal environment and the children’s body, to discuss the adverse effects of thermal environment on children, especially the case of heat stress, and to propose measures that could be applied to improve the thermal environment of schoolyards, focusing on vegetation. Human thermal comfort monitoring tools are mainly developed for adults, thus, further research is needed to adapt them to children. The schemes that are usually followed to design urban schoolyards create conditions that favour the exposure of children to excessive heat, inducing high health risks to them. The literature survey showed that typical urban schoolyard design (i.e., dense surface materials, absence of trees) triggered high surface temperatures (that may exceed 58 °C) and increased absorption of radiative heat load (that may exceed 64 °C in terms of Mean Radiant Temperature) during a clear day with intense solar radiation. Furthermore, vegetation cover has a positive impact on schoolyard’s microclimate, by improving thermal comfort and reducing heat stress perception of children. Design options for urban schoolyards and strategies that can mitigate the adverse effects of heat stress are proposed with focus on vegetation cover that affect positively their thermal environment and improve their aesthetic and functionality.

A Human Energy Balance Model With Clothing Effects for Estimating Human Thermal Comfort

2010 ◽  
Author(s):  
Atsumasa Yoshida ◽  
Yasuhiro Shimazaki ◽  
Shinichi Kinoshita ◽  
Ryota Suzuki
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Thermal Comfort ◽  
Human Body ◽  
Thermal Load ◽  
Thermal Environment ◽  
Energy Balance Model ◽  
Balance Model ◽  
Comfort Index ◽  
Human Thermal Comfort

There is an increased world attention on environmental issues with the global trend of environmental degradation. Especially thermal environment was highly concerned as human safety. We have been focused on creation of amenity environment with energy-saving way. This study is uncommonly dealing with human feeling for human thermal comfort, that is to say quantification of environment has been done. The feeling of comfort is mixed sense and can be totally easier to improve compared with straightforward way, and this may lead to energy and cost saving way of improvement. Moreover, this is human-oriented and can reflect humans’ wishes. Since thermal comfort index is useful tool for understanding the present state and evaluating the impact of countermeasures, effectiveness of human thermal load which is thermal comfort index based on energy balance of human body was examined. The human thermal comfort around the human body in outdoor is influenced by six dominant factors; air temperature, humidity, solar radiation, wind speed, metabolism and clothing. The difference between indoor and outdoor is expressed mainly as non-uniform and unsteady. Therefore, the unsteady responses of each dominant factors were examined and clarified human thermal load is quite good estimation of human thermal comfort. In steady state and even in unsteady state, thermal comfort can be obtained by using human thermal load on the whole. The reason is human thermal load consider the amount of physiology and also weather parameters. In the process of creating energy balance model of human, clothing material was deeply considered. For establishing better thermal environment, clothing material is of great use, because clothing material has an impact on thermal exchange between exterior environment and human body and more easy way to improve in 6 factors. The traditional treatment of clothing in human science was only resistance of heat transfer and this was not enough for all clothing effects. In daily life, effect of humidity exists and moisture property is required. Moreover color of material has impact on energy balance in clothing material. In order to show a way of better thermal environment, the heat and the moisture transfer coefficients on clothing material, radiative properties, and additional properties such as convection heat transfer coefficient were measured, and energy flow of clothing material was totally investigated. Finally, the effects of clothing material for human thermal comfort were predicted and this energy balance human model has become much better model.

A study on the heat dissipation and thermal environment of a novel heated bed

2018 ◽  
Vol 42 (5) ◽  
pp. 629-651 ◽  
Author(s):  
Dengjia Wang ◽  
Xiaowen Wang ◽  
Yanfeng Liu ◽  
Penghao Chen ◽  
Jiaping Liu
Keyword(s):  
Thermal Comfort ◽  
Heat Dissipation ◽  
Thermal Environment ◽  
Process Analysis ◽  
District Heating ◽  
Heat Transfer Process ◽  
Time Sharing ◽  
Indoor Thermal Environment ◽  
Human Thermal Comfort ◽  
Heating Energy Consumption

This study proposes a novel heated bed that can heat the whole room in the daytime and heat the surroundings of the bed at night. The conditions of conversion between the daytime and nighttime are achieved by the opening and closing of the fan and vents. The simplified calculation method of heat dissipation of the bed was obtained via the flow and heat transfer process analysis in two heating modes. Numerical simulations of heat dissipation and indoor thermal environment under different conditions in the daytime and nighttime were performed using computational fluid dynamics (CFD) to master the indoor temperature distribution characteristics. The simulation results were compared with the experimental results and show good agreement. The results show that the maximum of heat dissipation can reach 1300 W in the daytime and the indoor thermal environment can meet the human thermal comfort requirement. At night, the bed can create a high-temperature circle around it, which can ensure the sleep thermal comfort of the human body at a cooler indoor thermal environment, whose temperature can be 5°C lower than normal conditions. The heated bed can achieve the time-sharing district heating of room and reduce the heating energy consumption significantly. This study can provide the design and selection basis for the heated bed.

scholarly journals Effects of urban street trees on human thermal comfort and physiological indices: a case study in Changchun city, China

2021 ◽  
Author(s):  
Zhibin Ren ◽  
Hongbo Zhao ◽  
Yao Fu ◽  
Lu Xiao ◽  
Yulin Dong
Keyword(s):  
Blood Pressure ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Physiological Parameters ◽  
Tree Cover ◽  
Street Trees ◽  
Urban Street ◽  
Human Thermal Comfort ◽  
Physiological Indices ◽  
Urban Thermal Environment

AbstractPlanting trees along urban streets is one of the most important strategies to improve the urban thermal environment. However, the net impacts of urban street trees on human thermal comfort and physiological parameters are still less clear. On three similar east–west orientated streets with different degrees of tree cover—low (13%), medium (35%), and high (75%), urban microclimatic parameters and human physiological indices for six male students were simultaneously measured on three cloudless days in summer 2018. The results show that the differences in tree cover were predominant in influencing urban thermal environment and comfort. The street with the highest tree cover had significantly lower physiological equivalent temperature (PET) and more comfortable than the other two streets. The frequency of strong heat stress (PET > 35 °C) was 64%, 11%, and 0%, respectively, for streets with low, medium, and high tree cover. For the six male university students, human physiological indices varied greatly across the three streets with different tree cover. Systolic blood pressure, diastolic blood pressure, and pulse rate increased with decreasing tree cover. The results also suggest that urban thermal environment and comfort had considerable impact on human physiological parameters. Our study provides reasons for urban planners to plant trees along streets to improve the thermal environment and promote urban sustainability.

scholarly journals Impact of ventilation system type on indoor thermal environment and human thermal comfort in a ceiling cooling room

2021 ◽  
pp. 277-277
Author(s):  
Xiaozhou Wu ◽  
Genglin Liu ◽  
Jie Gao ◽  
Shuang Wu
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Ventilation System ◽  
Physical Parameters ◽  
Curtain Wall ◽  
Indoor Thermal Environment ◽  
Human Thermal Comfort ◽  
System Type

A ceiling cooling (CC) system integrated with a mechanical ventilation system is an advanced HVAC system for the modern office building with glass curtain wall. In this paper, considering the influence of heat transfer of external envelope, the indoor thermal environment and human thermal comfort were objectively measured and subjectively evaluated in a ceiling cooling room with mixing ventilation (MV) or underfloor air distribution (UFAD). Indoor physical parameters and human skin temperatures were measured as the chilled ceiling surface temperature and supply air temperature were 17.1?C-17.6?C and 22.2?C - 22.6?C. Simultaneously, 16 subjects (8 males and 8 females) were selected to subjectively evaluate the thermal environment. The results showed that the difference between mean radiant temperature and air temperature in the occupied zone was 0.8?C with CC+MV and 1.2?C with CC+UFAD, and the indoor air velocity was 0.17m/s with CC+MV and 0.13m/s with CC+UFAD. In addition, the calculated and measured thermal sensation votes with CC+MV were all slightly less than those with CC+UFAD. Therefore, ventilation system type had a slight impact on the indoor thermal environment and human thermal comfort in the ceiling cooling room.

scholarly journals РЕГРЕСІЙНА МОДЕЛЬ ПРОСТОРУ СТАНІВ ТЕПЛОВОГО КОМФОРТУ

2020 ◽  
Vol 138 (5) ◽  
pp. 26-34
Author(s):  
П. О. Яганов ◽  
І. В. Редько
Keyword(s):  
Regression Analysis ◽  
Thermal Comfort ◽  
Formal Model ◽  
Thermal Environment ◽  
The State ◽  
Regression Equations ◽  
Comfort Index ◽  
Operating Modes ◽  
Human Thermal Comfort ◽  
System States

Modeling the hyperspace of system states by the method of regression analysis, mathematical analysis of regression equations that model the thermal comfort index, optimization of thermal comfort by determining the coordinates of the projection of the vector image of thermal comfort onto a state hyperplane and solving an equation with many variables. Development of methods and models for a formal description of the space of states of human thermal comfort. The use of the method of regression analysis as a tool for modeling the state of thermal comfort in multidimensional hyperspace of system states is investigated. The procedure for calculating the PMV thermal comfort index and the formation of control commands for ACS of the thermal environment have been simplified. It is proved that a linear and quasilinear model of the state surface of the TC system within the selected TC intervals with sufficient accuracy for practical use calculates the PMV thermal comfort index. The regression analysis method is developed and extended to the class of thermal comfort systems. For the first time, a formal model of the space of states of thermal comfort is represented by linear and quasilinear polynomials. The state model of a complex multifactor system for providing thermal comfort for a person is represented by regression polynomials in a linear and quasilinear form, which greatly simplifies the calculation of the PMV index, classification of the state of thermal comfort, the search for optimal operating modes and command formation for actuators that are part of the ACS of the TC.

Assessment of thermal comfort in high-occupancy spaces with relevance to air distribution schemes: A case study of mosques

2018 ◽  
Vol 39 (5) ◽  
pp. 572-589 ◽  
Author(s):  
S Samiuddin ◽  
Ismail M Budaiwi
Keyword(s):  
Thermal Comfort ◽  
Performance Index ◽  
Distribution System ◽  
Thermal Environment ◽  
Terminal Velocity ◽  
Air Distribution ◽  
Human Thermal Comfort ◽  
Index Value ◽  
Air Diffusion

In high-occupancy intermittently operated buildings such as mosques and auditoriums, maintaining an acceptable thermal environment may present a challenging task. Variations in the operation and the thermal loads can result in variable and non-uniform thermal comfort conditions when the HVAC system is not properly designed. Non-uniformity of the thermal environment is greatly influenced by the design and scheme of the air distribution system. Mosques, with their distinctive five intermittent short occupancies and the non-fixed posture of occupants, present a unique case for investigation. In this study, the effect of air distribution of various schemes of a ceiling-based system on the thermal comfort in mosques is investigated. Air diffusion performance index and Fanger’s PMV method are used to assess thermal comfort. Three air distribution schemes at four diffuser terminal velocities were studied using the EnergyPlus and computational fluid dynamics techniques. Results indicate major variations in air diffusion performance index with each air distribution scheme type and diffuser terminal velocity. The uniformity of the PMV was entirely dependent on the air diffusion performance index value and exhibited large variations when the air diffusion performance index value was low. In most cases, the space was overcooled with an average PMV of −0.66 or below. Practical application: The effect of air distribution system design on human thermal comfort has been very complex to understand, as it involves different schemes and different diffuser discharge velocities. This study will help engineers and designers in designing better thermal environment for the occupants.

Effects of phased sleeping thermal environment regulation on human thermal comfort and sleep quality

2020 ◽  
Vol 181 ◽  
pp. 107108 ◽  
Author(s):  
Cong Song ◽  
Tingting Zhao ◽  
Zhiyuan Song ◽  
Yanfeng Liu
Keyword(s):  
Sleep Quality ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Human Thermal Comfort ◽  
Environment Regulation
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