Experimental investigation of performance for the novel flat plate solar collector with micro-channel heat pipe array (MHPA-FPC)

A novel flat plate solar collector with micro-channel heat pipe array (MHPA-FPC) is presented in this paper. Firstly, a preliminary test was conducted to investigate the thermal performance of the MHPA. It has been found that the surface temperature along the length of MHPA can get stable within 2 min. The temperature difference between the evaporator and condenser sections was less than 1 °C, which indicates that the MHPA has excellent isothermal ability and quick thermal respond speed. Based on these advantages, the MHPA was applied to the development of a novel solar collector. The performance test was conducted following the Chinese standard GB/T4271-2007, and a linear correlation between the instantaneous efficiency η and the reduced temperature parameter (Twi−Ta)·I−1 was established. The maximum instantaneous efficiency was found to be 80%, and the slope was −4.72. These values are 11.4% and 21.3% superior to the technical required values of the Chinese national standard. Test results were further compared with 6 groups of 15 samples coming either from either open literature or commercial products. The comparisons indicated that the maximum instantaneous efficiency of the MHPA-FPC surpassed 25% over the average level of those selected samples and better thermal insulation ability was presented by the MHPA-FPC. These results from this study demonstrate that the novel MHPA-FPC is one of the top level solar collectors among the current products.