Study on trough receiver for linear concentrating solar collector

In this paper, a trough black body cavity receiver for linear concentrating collector, which has potential application at moderate working temperatures (near 100 degrees C) or higher temperature (above 1.80 degrees C), has been studied. Four different shapes of the receiver have been proposed and tested. The optical efficiencies of the four receivers are simulated by using light tracking method. The thermal performances of the cavity receivers are tested under temperature levels, 90 degrees C and 150 degrees C, where the concentrated solar radiation is simulated by electric heating film. Both optical and thermal analysis illustrates that the triangle trough receiver is the best choice. To reduce the thermal losses, three kinds of glass cover are fixed on the cavity receiver. The thermal losses of the three different receivers with glass cover have been tested, when the inlet temperature varies from 35 degrees C to 95 degrees C. The experimental results indicate that the glass cover can reduce the thermal losses effectively. The semicircular cavity is tested in an linear concentrating solar collector, in which the sunlight is concentrated by a linear Fresnel lens(aperture width is 0.4m and optical efficiency is 0.7) and scatters on the semicircular cavity wall, absorbed by the copper tube and transmitted to working fluid. The highest average efficiency can reach 43% when the inlet temperature of the working fluid is 90 degrees C. It is found from experimental results that the efficiency of this designed cavity receiver is a little lower than that of evacuated tube, but has good potential in application because it is cheap and can be manufactured easily.