The Study Of PV/T System Based On Thin Linear Fresnel Transmission Condenser

At present,the environmental pollution is getting more and more serious and the energy dilemma is going to come in our society.The development and value of new energy has become the focus of attention of all mankind.As a widely distributed and renewable clean energy,solar energy is the research focus of new energy.In the development and value of solar power,photovoltaic power technology and solar warm technology has been the most important two directions in solar energy application research.On the one hand the application of the integrated solar energy can improve energy density per unit area,improve the efficiency of battery power,reduce the area of battery.On the other hand it can also be cooled by solar energy conversion system.Then it can collect heat to improve the comprehensive utilization efficiency of PV/T system.After summarizing and analyzing the research results of the existing solar transmission PV/T system,this paper presents a new PV/T system based on the thin linear Fresnel concentrator.The experimental device is designed and the performance of the device is evaluated through the detailed theoretical analysis and system simulation.Finally,the device is tested experimentally,and the results of experiment and theory are compared,pointing out the direction of system improvement.The main points of this paper are as follows:The variation of the system reception efficiency with the azimuth and elevation angle tracking errors is obtained.The design and the optical simulation of the secondary condenser are put into practice.The secondary condenser which it is the CPC structure and the Fresnel condenser are combined.When the design and optical simulation of the linear Fresnel condenser are completed on the basis of the north-south arrangement of the whole device,it can be seen from the optical simulation that the altitude angle tracking error is between 0°-15° and the azimuth angle tracking error is within the range of 0°-0.4°,the condenser’s receiving efficiency can be guaranteed to be over 80%.And we take into account the selection of condenser battery,the theoretical analysis of the system on the tracking angle requirements.We design cooling system which based on heat recovery,then we test the device.The mathematical model of PV/T system for linear Fresnel transmission concentrating was established.Using matlab to solve the model,we get the temperature change of the hot plate and the cell under different solar irradiance.And we get the change of the system thermoelectric efficiency and total utilization efficiency with solar irradiance.The transmission concentrating PV/T system based on thin-plate linear Fresnel concentrator is studied.The voltammetric characteristics of the concentrator battery under concentrated and un-concentrated conditions,the volt-ampere characteristics under different irradiance values and the output power under different load resistances are tested.And we test battery temperature with the radiation intensity changes under concentrated and un-concentrated conditions in the actual weather.The relationship between the short-circuit current and irradiance,the open-circuit voltage and the battery temperature under condenser condition are also tested.The flare condition of the thin linear Fresnel condenser under different bending conditions and actual weather conditions is also tested.Finally,the temperature distribution of the heat-pipe aluminum isothermal plate is tested according to the PV/T system.And the change of thermal/electric power,the thermoelectric efficiency and the total utilization efficiency are also tested under actual weather conditions.The experimental and simulation results of temperature,thermoelectric efficiency and total efficiency of the system are compared and analyzed.The test results show that: the thermal efficiency of system almost reached a maximum of 32.0%,electrical efficiency almost reached to 25.0%,and the total efficiency almost reached to 57.0% at noon.