Fan Man, Wang Jia, Zhang Lanlan, Li Han, Kong Xiangfei, Zheng Chenxiao
School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401 China.
State Key Laboratory of Building Safety and Built Environment, Beijing, 100013 China.
Build Simul. 2022;15(7):1309-1321. doi: 10.1007/s12273-021-0856-x. Epub 2021 Nov 25.
The couple of radiation with convection heating owned advantages of less energy utilization, healthier and more comfortable indoor environment. However, local thermal discomfort was often induced by large vertical temperature difference and radiation asymmetry temperature. This work studied indoor thermal environment characteristics under different coupling ways of radiation and convection heating terminals through experiments and CFD simulation. The studied five scenarios were denoted as: (I) lateral air supply + adjacent side wall radiation, (II) lateral air supply + opposite side wall radiation, (III) lateral air supply + floor radiation, (IV) lateral air supply + adjacent side wall radiation + floor radiation, and (V) lateral air supply + opposite side wall radiation + floor radiation. The overall thermal comfort indices (including air diffusion performance index (ADPI), predicted mean vote (PMV), and predicted percent of dissatisfaction (PPD)) and local thermal comfort indices under different scenarios were investigated. For Scenarios I-III, the local dissatisfaction rates caused by vertical air temperature difference were 0.4%, 0.1%, and 0.2%, respectively, which belonged to "A" class according to the ISO-7730 Standard. While the vertical asymmetric radiation temperature of Scenario I/II was about 6.5 °C lower than that of Scenario III/IV/V. The ADPI for Scenarios III-V were about respectively 5.7%, 16.7%, and 21.0% higher than that of Scenarios I-II, indicating that a large radiation area and radiation angle coefficient could reduce the discomfort caused by radiant temperature asymmetry. The coupling mode improved local discomfort by decreasing vertical temperature difference and radiation asymmetry temperature wherefore improving the PMV from -1.6 to -1. The lateral air supply coupled with asymmetric radiation heating could potentially improve the thermal comfort of occupied area, while the comprehensive effect of thermal environmental improvement, energy-saving, and cost-effectiveness needes to be further investigated.
辐射与对流耦合供暖具有能源利用率低、室内环境更健康舒适等优点。然而，较大的垂直温差和辐射不对称温度常常会引起局部热不适。本研究通过实验和CFD模拟，研究了辐射与对流供暖末端不同耦合方式下的室内热环境特性。所研究的五种工况分别为：（I）侧向送风+相邻侧壁辐射，（II）侧向送风+相对侧壁辐射，（III）侧向送风+地板辐射，（IV）侧向送风+相邻侧壁辐射+地板辐射，以及（V）侧向送风+相对侧壁辐射+地板辐射。研究了不同工况下的整体热舒适指标（包括空气扩散性能指标（ADPI）、预测平均评价（PMV）和预测不满意百分比（PPD））以及局部热舒适指标。对于工况I-III，由垂直空气温差引起的局部不满意率分别为0.4%、0.1%和0.2%，根据ISO-7730标准属于“A”级。而工况I/II的垂直不对称辐射温度比工况III/IV/V低约6.5℃。工况III-V的ADPI分别比工况I-II高约5.7%、16.7%和21.0%，表明较大的辐射面积和辐射角系数可以减少辐射温度不对称引起的不适。耦合模式通过降低垂直温差和辐射不对称温度改善了局部不适，从而将PMV从-1.6提高到-1。侧向送风与不对称辐射供暖相结合有可能提高居住区域的热舒适性，而热环境改善、节能和成本效益的综合效果仍需进一步研究。
