To explore the human body thermal comfort under radiative cooling air conditioning system
the heat transfer mechanism of radiative cooling air conditioning system is investigated. The relationship of the thermal comfort indicator with the human body's sensible heat loss and the ratio of radiative heat loss to convective heat loss is achieved. Both experimental and numerical results show that the human body thermal comfort index
i.e.
predicted mean vote(PMV)
is approximately linear with the sensible heat loss of human body under the radiative cooling air conditioning system. Thus
the human body thermal comfort could be directly evaluated by the human body thermal balance according to the obtained linear relationship. Furthermore
it is found that the ratio of radiative heat loss to convective heat loss of human body has no effect on PMV. Therefore
on the basis of maintaining human body thermal comfort
it is conceivable that the higher ratio of radiative heat loss to convective heat loss
which means larger radiative area or higher air supply temperature
could be beneficial to energy conservation. This study may provide a reference for both assessment of human body thermal comfort and system design of radiative cooling air conditioning system.
XU Xiangyang, YANG Jie, ZHANG Qiqi, et al. Experimental study of room temperature and humidity distribution of radiant air-conditioning system in summer [J]. Fluid Machinery, 2013, 41(2): 53-57.
ZHAO Yugen, LI Qiangmin. Characteristics and application of cooling ceiling system [J]. Building Energy Environment, 1999, 18(1): 30-32.
CATALINA T, VIRGONE J, KUZNIK F. Evaluation of thermal comfort using combined CFD and experimentation study in a test room equipped with a cooling ceiling [J]. Building Environment, 2009, 44(8): 1740-1750.
FANGER P O. Thermal environment: human requirements [J]. Environmentalist, 1986, 6(4): 275-278.
American Society of Heating, Refrigerating, and Air Conditioning Engineers. ASHRAE handbook of fundamentals [M]. Atlanta, USA: ASHRAE, 2009: 170-200.
KEIL D, GOLDIN D. Study on indoor thermal environment of office space controlled by cooling panel system using field measurement and the numerical simulation [J]. Building Environment, 2005, 40(3): 301-310.
MEMOM R A, CHIRARATTANANON S, VANGTOOK P. Thermal comfort assessment and application of radiant cooling: a case study [J]. Building Environment, 2008, 43(7): 1185-1196.
SIMMONDS P. Practical applications of radiant heating and cooling to maintain comfort conditions [J]. ASHRAE Transactions, 1996, 102(1): 650-675.
GAN G. Numerical method for a full assessment of indoor thermal comfort [J]. Indoor Air, 1994, 4(3): 154-168.
GAN G. Evaluation of room air distribution systems using computational fluid dynamics [J]. Energy and Buildings, 1995, 23(2): 83-93.
ZHU Neng, LIU Shan. Thermal comfort with displacement ventilation combined with chilled ceiling system [J]. Journal of Refrigeration, 2000, 21(4): 64-70.
HODDER S, LOVEDAY D, PARSONS K, et al. Thermal comfort in chilled ceiling and displacement ventilation environments: vertical radiant temperature asymmetry effects [J]. Energy and Buildings, 1998, 27(2): 167-173.
LOVRDAY D, PARSONS K, TAKI A, et al. Displacement ventilation environments with chilled ceilings: thermal comfort design within the context of the BS EN ISO7730 versus adaptive debate [J]. Energy and Buildings, 2002, 34(6): 573-579.
LIN Z, DENG S. A study on the thermal comfort in sleeping environments in the subtropics: developing a thermal comfort model for sleeping environments [J]. Building and Environment, 2008, 43(1): 70-81.
BURTON A C, EDHOLM O G. Man in a cold environment [J]. American Journal of Physical Anthropology, 1956, 14(2): 337-339.
MURAKAMI S, KATO S, ZENG J. Combined simulation of airflow, radiation and moisture transport for heat release from a human body [J]. Building Environment, 1998, 35(6): 489-500.
DE DEAR R J, ARENS E, HUI Z, et al. Convective and radiative heat transfer coefficients for individual human body segments [J]. International Journal of Biometeorology, 1997, 40(3): 141-156.
GAGGE A P, BURTON A C, BAZETT H C. A practical system of units for the description of the heat exchange of man with his environment [J]. Science, 1941, 94(2445): 428-430.