Experimental investigation and performance evaluation of a vacuum tube solar air collector based on micro heat pipe arrays

An experimental study was conducted to evaluate the thermal performance of a vacuum tube solar air collector that is based on micro heat pipe arrays (MHPA) and features wavelike fins attached to the condenser section of the MHPA. The experimental results were used to analyze the thermal performance of the collector, particularly the temperature distribution in the different localizations of the air collector. The heat loss analysis provided a useful parameter to evaluate the heat loss of the collector. Results showed that a decrease in the inlet, will led to an increase in efficiency because of the reduced heat losses to the environment. The daily thermal efficiency varied between 50% and 70%. In the performance analysis of the MHPA collector, varying flow rates were employed to observe the change in efficiency, outlet temperature, MHPA temperature behavior variation vs. solar radiation, and air flow rate. The utilization of the collector can reduce the amount of emissions of gaseous waste emissions, which has large energy saving potential and environmental benefits. The proposed MHPA-based vacuum tube solar air collector shows good potential in large-scale applications, such as in the room heating of farmhouses, industrial buildings, and remote outposts, as well as in the agricultural sector. (C) 2016 Elsevier Ltd. All rights reserved.