| As a new type of energy saving and comfort air-conditioning, radiant cooling technologyhas pressing prospects of application. Radiant cooling environment belongs to typicalnon-uniform thermal environment, and the laying mode of radiant terminal units has a highlyeffect on the heterogeneous characteristics of thermal environment, while most engineeringdesigners does not clearly recognize the caused effect of different laying mode from theaspects of thermal comfort. In this paper, thermal comfort of human body in the non-uniformradiant cooling environment was studied around thermal comfort and thermal discomfortcaused by radiation asymmetry and the main researches were developed as follows:Firstly, the residential buildings with radiant cooling system were experimentally studied.Practical running result of the application combining radiant cooling and dedicated outdoorair was analyzed in detail under stable and intermittent operation condition, and indoorthermal environment and human thermal comfort in two cases were evaluated, whichprovided theoretical basis and experimental verification for subsequent numerical models.Secondly, the real human thermal sensation test was carried out on radiant cooling systemby the TSV model, considering the general thermal sensation and local thermal sensation, andthe value evaluating thermal environment was summarized to compare with the calculatedvalue from the PMV-PPD model of thermal comfort. Studies have shown that TSV isgenerally higher than that of PMV index calculation, the average difference of about0.8, thetime of test，physical quality and psychological expectations were the main reasons for thedeviation.Thirdly, the numerical model of radiant cooling was built，and the effectiveness wasverified by using the measured data, the four assembly cases that the terminal units ofradiation cooling system were in ceiling, floor, side wall, were numerically simulated. Thecalculated result was analyzed and discussed mainly from the three aspects, indoor thermalenvironment, human body thermal comfort and local thermal discomfort. It was indicated thatindoor vertical temperature distribution was the most uniform when the terminal units was setin ceiling, and the cooling efficiency on human active area when set in the floor was themaximum with the mean temperature lower about0.3℃than setting in the ceiling in therange of0.1~1.1m high. The predicted indoor thermal sensation index satisfied therequirement of comfort zone. Fourthly, the cases with different laying areas under ceiling and floor radiant coolingconditions were compared and researched from thermal comfort aspect, and the effect onindoor thermal environment and human body thermal comfort was analyzed. It turned out thatwhen the laying rate of ceiling and floor radiation plate were below40%and20%respectively, the temperature difference between the cold plate wall and indoor meanradiation was too large, and the asymmetry of radiation would cause local thermal discomfortin the face of the cold plate, in addition, the inhomogeneity of indoor temperature distributionwas more serious. Therefore it can be concluded that laying rate of ceiling and floor radiationplate within60%~100%and60%~80%respectively was relatively rational.At last, the individual control of local cooling on thermal environment was researched tooptimally design the tall office buildings which needed local temperature controlling. It showsthat in the case of decreasing cooling by40%, compared with the fully laid end of the floorradiation, local cooling can reduce the temperature around people in office section about1.5~2℃and reach better thermal comfort. Increasing the supply air and applying local wallcooling can reduce the vertical temperature gradient and decrease local thermal discomfort.The research result obtained in this paper can provide theoretical reference for designingterminal units of radiant cooling system and drive the promotion of radiant coolingair-conditioning. |
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