Effect Of Solar Radiation On Floor Cooling Performance

Large space office buildings have the characteristics of multiple transparent enclosure structures,strong solar radiation incident indoors,and high wall temperature of the enclosure structure.When the radiation cooling system based on radiation heat exchange is applied in these occasions,the radiation terminal can directly absorb the solar short-wave radiation,so that its cooling capacity is enhanced,and at the same time,there is no need to design a complicated airflow organization.Therefore,this paper systematically analyzes the influence of solar radiation heat gain on radiant floor cooling capacity,the design capacity of the fan-coil system used as a supplementary cooling source,and the energy consumption of the building under different window-to-wall ratios.First,the theoretical analysis of the heat transfer characteristics of the radiant floor cooling system is carried out,the current norms and methods for calculating the heat transfer heat flow and cooling capacity of the radiant floor surface are summarized.And points out that applying the existing manual calculation method to the occasions where the incident solar radiation is relatively strong will cause the calculation result to be smaller.Secondly,based on an experimental room in Changsha area,a numerical model of the experimental room using radiant floor combined with fan-coil cooling system is established based on EnergyPlus software.By comparing the simulation results of the numerical model under the actual outdoor meteorological parameters and solar radiation intensity with the measured results,the correctness of the established numerical model and related parameter settings and the reliability of the simulation software are verified.Then,the numerical models under different window-to-wall ratios and outdoor solar radiation intensity conditions were simulated,the influence of solar radiation on the cooling capacity of the radiant floor and the design capacity of the fan coil system were analyzed.Furthermore,a simplified calculation method for radiant floor cooling capacity with window-to-wall ratio and total solar radiation intensity as independent variables is proposed by curve fitting,which provides a certain reference basis for the capacity design of different radiant floors combined with fan-coil cooling systems.Finally,Ecotect software combined with EnergyPlus software are used to make a detailed analysis of the indoor lighting condition,construction energy consumption and air conditioning energy efficiency ratio of the numerical models under different window-to-wall ratios on summer design days.Considering the human body’s demand for natural lighting and the total energy consumption of construction,it is proposed that the rational glazing ratio range of the south exterior window of the building using radiant floor combined with fan-coil cooling system is 0.3-0.6,And the window-to-wall ratio is best controlled at about 0.5.