Proof Of Concept And Thermal Characteristics Study Of Window Of Partitioned Cavities With Gravity Driven Enhanced Cooling By Simulation

As one of the building envelope,the exterior windows have great potential in energy saving.Conventional air conditioning system handles the different heat and cooling loads in a unified framework,but the heat or cooling loads from the exterior windows are low-grade loads that can be handled by low-grade heat source or sink.Therefore,this thesis proposes a window of partitioned cavities with gravity driven enhanced cooling,which can make use of high-temperature heat sink and effectively block the air conditioning load from exterior windows of buildings in summer.Firstly,the structure and heat transfer mechanism of window of partitioned cavities with enhanced cooling are analyzed,based on which a numerical model of window of partitioned cavities with enhanced cooling is established using ANSYS Fluent software to provide a basis for subsequent simulation and comparison.Then numerical simulation is used to verify the feasibility of this window of partitioned cavities with enhanced cooling.Secondly,the influence of the structural parameters of window of partitioned cavities with enhanced cooling on its heat transfer characteristics is analyzed and compared,including the thermal conductivity of the film,the width of the cavity,the temperature of the heat sink,the number of cooling pipes,the presence or absence of fins.The heat flow rate transferred to the room is used as the main index to evaluate the performance of window of partitioned cavities with enhanced cooling,and the main factors and trends affecting the performance of window of partitioned cavities with enhanced cooling in summer are derived based on the simulation results.Among them,the number of cooling tubes has a greater effect on the heat transfer through the windows as 3.8%～5.9%,while the thermal conductivity of the membrane has a smaller effect,less than 1%.Finally,for the thermal response of window of partitioned cavities with enhanced cooling,empirical formulas for convenient calculation are obtained under steady-state and nonsteady-state conditions respectively.The thermal response of the window under steady-state conditions can be calculated by the linear equation about the outdoor air temperature,solar radiation and heat sink temperature where the error does not exceed 5 W;the thermal response under non-steady-state conditions can be calculated by using the virtual RC model with the weighted sum of the thermal response of the window corresponding to the steadystate boundary conditions at the current moment and the previous moment and the average relative error is about 13%.Through the above research,this thesis provides a proof of concept and parameters analysis for window of partitioned cavities with enhanced cooling,which provides basis for further research.