Study On The Optical And Thermal Transmission Characteristics Of A Roof Tile Type Parabolic Non Tracking Solar Aggregator

With the increasing of the building volume and the continuous development of the function,it has an important application prospect to reduce the energy consumption of the building hot water and air conditioning,and to construct the solar energy conversion and the integration of the building.Based on the geometrical optics principle of non-tracking solar energy aggregation transmission and the photothermal conversion technology,a non-tracking solar energy aggregator is developed,which takes into account solar energy collection,rainwater excretion and restrains the energy consumption of the top air conditioning.By means of theoretical analysis,numerical simulation and experimental measurement,the characteristics of non-tracking solar energy aggregation transmission and photothermal conversion are studied and analyzed.According to the characteristics of solar motion trajectory and the geometrical optics theory of directional radiation transmission of two-dimensional paraboloid aggregator,a new structure design scheme of two-dimensional long strip improved parabolic non-tracking aggregator is proposed.The endothermic tube of the non-tracking aggregator is at the top of the aggregator and can also collect and utilize solar radiation energy when the solar angle is low(the morning and evening).A plurality of non-tracking aggregators are assembled to form a wave-type roof tile structure.On the basis of this,a tile-type accumulator device is developed and the experimental platform of photothermal conversion is established.The optical path transmission model of non-tracking concentrator is established.The angle of conical angle,surface error,installation angle and non-tracking inclined incident angle are taken into account.The Monte Carlo ray tracing method(MCRTM:Monte Carlo Ray Tracing Method)is used to simulate and analyze the non-tracking solar light aggregation characteristics of the non-tracking aggregator,and the dynamic aggregation energy flow density distribution characteristics at different times are obtained.The heat flux input condition is provided for the photothermal conversion of the non-tracking aggregator.According to the principle of photothermal energy conservation,considering the thermal interaction between the dynamic incident external heat source of solar light and the internal tube,external tube,fluid in the vacuum tube,and the external environment,a one-dimensional quasi-steady coupled heat transfer model of the tile collector is established.The characteristics of endothermic heating of fluid in pipe are calculated and analyzed by programming code.At the same time,the characteristics of endothermic heating of fluid in the tube were measured on the platform of photothermal conversion of tile aggregator.By comparing the experimental results with the simulation results,the coupled heat transfer model is perfected and the reliability of the calculation model is verified.Based on the experimental measurement scheme and research method of heat transfer,a measuring device for heat conversion characteristics was established,and the heat transfer performance of tile collector was studied experimentally.At the same time,compared with the traditional two kinds of solar vacuum collector,the instantaneous thermal efficiency of the tile type collector is improved and the daily average thermal efficiency is improved about 12%.The feasibility of optical transmission design of tile aggregator is verified.In this paper,the design method of the tile type non tracking aggregator and the characteristics of the heat transfer are studied and analyzed.The main influencing factors of the optical heat transfer efficiency and the improvement methods are revealed.The related conclusions provide technical support for the development of the non tracking solar aggregator technology and the new energy development of the building.