Thermo-dynamic Performance Of Concrete Core Cooling Slab

The radiant cooling air conditioning system has attracted more and more attention in the engineering and academic circles due to its advantages of energy saving and comfort.In the concrete core cooling slab systems,due to the intervention of large capacity regenerator,the dynamic heat transfer process becomes complicated.Only by mastering the dynamic response characteristics of concrete core cooling slab systems and getting full use in engineer practice,the energy saving effect of concrete core cooling slab systems can be achieved.In this paper,the advantages of frequency-domain regression method are determined by analyzing the existing simplified heat transfer model.Based on the identification theory and reaction coefficient method,two-dimensional unsteady heat transfer model of concrete core cooling slab is established.In this model,the thermal response factors of concrete core cooling slab are calculated by frequency-domain regression method.Then heat transfer process model along pipe is also made.The simplified heat transfer model was validated by the experimental data of steady state and unsteady state.At last,the thermo-dynamic performance of concrete core cooling slab is analyzed by the model.The following conclusions were obtained.Firstly,the two-dimensional and three-dimensional unsteady heat transfer model of concrete core cooling slab is established by frequency-domain regression method.The model was validated with the experiments data.The error of slab surface heat flux and surface temperature is within 6% and 0.3℃ in steady conditions and within 9% and 0.7℃ in unsteady conditions;Secondly,using simplified heat transfer model,the thermo-dynamic performance of concrete core cooling slab was calculated,the results show that the heat storage layer thickness of commonly engineering structure forms was calculated: 50-130 mm in no thermal insulation layer;On the contrary,the layer thickness is 100-200 mm;Thirdly,in the condition of that indoor reference temperature and the heat gain have same changes,the calculation formula which responses the conversion of heat gain and cooling load in concrete core cooling slab system of the attenuation coefficient and the delay time is determined.All of conclusion can provide reference for the load calculation and operation strategy of concrete core cooling slab system.