Performance analysis of a novel sun-tracking CPC heat pipe evacuated tubular collector

A tracking compound parabolic concentrating (TCPC) solar collector with concentration ratio of 2.3, which combine the CPC, heat pipe evacuated tubular receiver and crank rod transmission mechanism together, was developed and studied in this paper. A theoretical model was created to simulate the solar incident angles and the optical performance of the TCPC collector. In addition, thermal performances of the TCPC collector at different operation modes were investigated experimentally. The simulation results show that, the transversal projection angle (θ_t) is the vital factor that affects the optical performance. When θ_t is within the range of -23.5°and 23.5°, the incident angle modifier (IAM) of the TCPC collector reaches 0.95∼1.14. By means of tracking, the average optical efficiency is over 60%, while it is decreased to 30% under the fixed mode (FM). The output energy of the TCPC collectors during the test period can be highly increased, which is 1.9∼2.3 times higher than that at the FM. Furthermore, the intermittent tracking mode (ITM) is more power frugal and efficient as the average optical efficiency is 3.6% higher than that at the Continuous tracking mode (CTM). These verify that the ITM is the optimal operation mode for the TCPC collectors.