地板辐射与下送风复合式供冷系统运行特性实验研究

Experimental study on operating performance of radiant floor cooling combined with underfloor ventilation system

测量地板辐射与下送风复合式供冷系统运行过程中的室内空气温湿度、围护结构表面温度等室内环境参数,分析室内温湿度、热舒适性、系统换热量的变化规律,并对室内空气环境进行影响因素分析。实验结果表明:室内空气绝对湿度较室内空气温度达到稳定需要的时间更短;MRT(mean radian temperature)、OT(operation temperature)和PMV-PPD值在系统开启后第1.0 h减小速率最大,1.5 h后逐渐趋于稳定,此时,PMV约为0.49,PPD约为10%,在热舒适范围内;地板净辐射换热量、对流换热量和总换热量在系统开启后的1.5 h内递增,然后趋于稳定,此时,地板辐射换热量约为37 W/m^2,占总换热量的47%;室内空气温度和作用温度均随室外综合温度、室内发热量、供回水平均温度和送风温度的增加而增加,当室外综合温度较低或较高,或室内发热量较低,或供回水平均温度较低时,室内空气温度和作用温度变化梯度较小,室内空气温度和作用温度随送风温度增加而增加的速率近似呈线性。

In radiant floor cooling combined with underfloor air conditioning system,indoor air temperatures and wall surface temperatures are measured.The variations of indoor air temperature and humidity,thermal comfort,heat-transfer capacity,and indoor air environment influencing factors are analyzed.Experimental results show that indoor air humidity costs less time to reach stable than indoor air temperature does due to the faster response of underfloor ventilation system,which is in charge of dehumidification and latent heat of the system,than radiant floor cooling system.MRT,OT and PMV-PPD value decrease rapidly in the first 1 h after the system operation and tend toward stability after 1.5 h.Under stable condition,PMV and PPD are approximately 0.49 and 10%,respectively,which are in the range of thermal comfort recommended value in ISO7730.Radiant,convective,and total heat transfer quantity increase in the first 1.5 h after the system operation,and then tend toward stability.Under stable condition,radiant heat transfer quantity is 37 W/m^2,which occupies 47%of the total.Indoor air temperature(IAT)and operative temperature(OT)increase with the increasing of disturbance and manipulated variables.The increasing ratio of IAT and OT are relatively small when comprehensive outdoor air temperature is relatively high or low,and indoor heat quantity or average water temperature is relatively low.IAT and OT increase approximately linearly with the increasing of supply air temperature.