Experimental Research On The Thermal Performance Of A Type Trough Solar Concentrator

Solar thermal power generation technology is one kind of technology for power generation that coverts solar radiation energy into electrical energy. It is an important development direction of solar energy utilization. At present, trough solar thermal power plants almost accounted for 90% of the total solar thermal power capacity. However, the cost of the trough solar collector accounted for more than 40% of the total investment of the power plant at the beginning. Therefore, improvement the performance of the trough solar collector is the key to improving the power generation efficiency of the power station and reducing the cost of power generation. A series of experimental research on the thermal performance of a new type of trough solar collector, which is developed by Southeast University. The main research contents and conclusions are summarized as follows:Firstly, the main components and features of trough solar collector are introduced in detail, including the vacuum collector tube, the parabolic reflecting mirror, tracking mechanism, stents and other auxiliary device. At the same time, the main characteristic parameters of the trough solar collector were analyzed, including the concentration ratio, receiving angle, interception factor, optical efficiency and so on.Secondly, the method which is adopted by the experiment is the quasi steady state equilibrium. According to the actual situation of outdoor circuit operation build the same loop in indoor to study the thermal performance of solar vacuum tube. Experimental results show that the radiation heat loss is the main collector heat loss, accounted for more than 80%. the heat loss of insulation layer on the surface of invalid optical length accounted for only 1.66%～4.04%; the oil inlet temperature and mass flow rate have a great effect on heat loss and the section temperature, they increase with the increase of the oil inlet temperature, increased first and then decreased trend with increase of mass flow, and the maximum difference of the section temperature reaches 9.6 degrees. It is concluded that on the surface of invalid optical length package thermal insulation layer in the process of the tube operation can reduce effectively the heat loss and the working environment will influence the heat flow density distribution inside of vacuum collector tube, appropriately increase the metal heat absorbing tube wall thickness, structure optimization of tube and improve the increase fluid flow can prevent effectively the occurrence of fatigue damage and tube bending deformation. Under the actual situation, selecting the fluid flow should consider the change of the heat loss and the economy of the system.Thirdly, the experimental system of the new trough solar collector which is used to do the thermal performance test is determined. Then the main components of the experimental test system were the creativity and design, including the deflection surface mirror, conformal bracket, control system of the collector and water tank, at the same time the measurement system and measurement method is expatiated respectively.At last, experimental study on the thermal performance of a new type of trough solar collector, the effect of water flow rate and solar radiation intensity on the thermal performance of the solar collector was researched. The experimental results show that:the water flow rate and the solar radiation intensity have great influence on the thermal efficiency of the collector. The heat efficiency of the collector is the same with the change of the solar radiation intensity, and the maximum efficiency of the collector is 46.6%. It is pointed out that it is effective way to improve the thermal efficiency of the system by fully automatic real-time tracking control, optimizing the design of the condenser group, the location of the power station and the suitable flow rate.