scholarly journals Thermal Comfort in the Passenger Compartment Using a 3-D Numerical Analysis and Comparison with Fanger’s Comfort Models

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 690 ◽  
Author(s):  
Saboora Khatoon ◽  
Man-Hoe Kim

The paper presents the human thermal comfort inside a car cabin using three-dimensional numerical analysis and state of the art comfort models. Vehicular thermal comfort is a must concern factor in modern car manufacturing industries. Numerical simulations have been performed to accurately predict the temperature inside the car cabin and velocity of airflow. The numerical results are then compared using Fanger’s model, the equivalent temperature model and the modified Fanger’s model. A link has been developed using a general thermal comfort index for the considered human thermal comfort models. The general thermal comfort index takes into consideration all the investigated parameters that affect the vehicular thermal comfort thereby evaluating the whole car environment. The thermally comfortable conditions for the driver and passengers in a vehicular cabin are also addressed based on some of the thermal comfort indexes available in literature. In addition, the solar load has also been added using a surface radiation model to consider the environmental heat load effect on cabin thermal comfort.

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094299
Author(s):  
Liang Zhang ◽  
Liangkui Qi ◽  
Jianhua Liu ◽  
Qingqing Wu

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.


Author(s):  
Atsumasa Yoshida ◽  
Yasuhiro Shimazaki ◽  
Shinichi Kinoshita ◽  
Ryota Suzuki

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.


Author(s):  
П. О. Яганов ◽  
І. В. Редько

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.


2007 ◽  
Vol E90-C (7) ◽  
pp. 1348-1355
Author(s):  
Z. SUN ◽  
M. RONG ◽  
Y. WU ◽  
J. LI ◽  
F. YANG

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2755 ◽  
Author(s):  
Karol Bandurski ◽  
Hanna Bandurska ◽  
Ewa Kazimierczak-Grygiel ◽  
Halina Koczyk

Hot and dry climate and air pollution is a growing problem in urban areas, and this can have an adverse impact on life and health of urban residents. One of the ways to protect people from this hazard is the use of urban green or street greenery. However, its implementation can be problematic in highly urbanized areas. This paper presents a concept of the green structure (GS), designed, and is still being developed, by Adam Kalinowski where cooling efficiency is based on the synergy of shade and evapotranspiration. The GS that could be used as street furniture, small architecture form or a public utility structure intended to protect people and objects from an adverse urban environment, at the same time providing pleasant and healthy microclimate inside. The pilot project-the first application of the GS in the urban environment-is presented and the results of short-term measurements of temperature and humidity are provided and analyzed. Moreover, a simple dynamic simulation of the GS performance in courtyards has been conducted. The obtained results show the decrease of the perceived temperature within this structure. Depending on climate type, an average potential reduction of Universal Thermal Comfort Index (UTCI) and mean radiant temperature (Tmrt), caused by the GS in a courtyard case study, is 5–8 °C and 17–29 °C, respectively. Performed simulation also confirms that TRNSYS software is an appropriate tool for simple outdoor microclimate analysis. Further research to develop this concept, increase its performance and customize it for different applications are proposed.


Volume 1 ◽  
2004 ◽  
Author(s):  
Nawaf Al-Mutawa ◽  
Walid Chakroun ◽  
Mohammad H. Hosni

It has been known that the human thermal comfort is not exclusively a function of air temperature but also a function of six additional parameters, namely, mean radiant temperature, air velocity, turbulence intensity, humidity, activity level, and clothing insulation. The combined physical and psychological impact of these parameters on thermal comfort is mathematically described in various comfort models. The current comfort models, while use extensive human comfort data, may not be applicable in all world regions due to environmental conditions and people’s expectations. The State of Kuwait has a population of 2.5 million inhabitants with majority of people living in a few populated cities with heavy vehicle traffic, office buildings, factories, petroleum operations, and shopping centers. During the summer months (especially in July and August) the temperature reaches 48 °C in the afternoon, and can sometimes exceed 55 °C requiring extensive use of air conditioning. The traditional clothing (Disdasha) is made of lightweight, white, fabric material to provide some level of comfort. To better understand the regional preferences and assess the applicability of the standard comfort models in Kuwait, important parameters influencing human thermal comfort were measured in ten different government offices and the corresponding PMV indices were calculated. The results were compared with other comfort indices to obtain the most viable comfort index and the appropriate temperature range for local comfort for Kuwait offices. This study is not only important for comfort evaluations but also for evaluation of energy consumption in office buildings.


2019 ◽  
Vol 29 (10) ◽  
pp. 3976-3993 ◽  
Author(s):  
Mahdi Ashoori ◽  
Ghanbarali Sheikhzadeh ◽  
Soroush Sadripour

Purpose The purpose of this study is to analyze the effect of using a ceiling fan with central heating system in the winter on thermal comfort and heat transfer rate in a three-dimensional numerically. Design/methodology/approach The geometry had certain dimensions, and an occupant was modeled to be in the room. In models which were used, the flow was turbulent, and turbulence models were used for simulating turbulence. Between all the models, k-ε model had best matching. Findings Results show that using the ceiling fan during the winter had an efficient and considerable effect on improving the thermal comfort and energy saving inside buildings. By the use of ceiling fan, the effective room temperature has increased by 2.5°C. Furthermore, results show that by using ceiling fan in the winter, the predicted mean vote and the predicted percentage dissatisfied indexes improved. At the end, the case Room 11-0.05-15 with temperature of 87°C for radiator and normal fan velocity of o.25m/s were the optimal model that caused the complete thermal comfort and reduced energy consumption up to 28 per cent. Originality/value In the present study, the effects of using the ceiling fans on human comfort condition and heat transfer field during the winter (heating system) are studied. Following are the goals for all models: getting the appropriate temperature for radiator so that thermal comfort condition can be applied at the height of 75 cm of the room, velocity for fan so that air speed can be 0.25m/s at the height of 2 m or lower of the room and position to place the fan.


2008 ◽  
Vol 57 (9) ◽  
pp. 5761
Author(s):  
Wu Yi ◽  
Rong Ming-Zhe ◽  
Yang Fei ◽  
Wang Xiao-Hua ◽  
Ma Qiang ◽  
...  

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