Design, fabrication and experimental study of a solar photovoltaic/loop-heat-pipe based heat pump system

• Published in: Solar energy 2013-11, Vol.97, p.551-568
• Main Authors: Zhang, Xingxing, Zhao, Xudong, Shen, Jingchun, Hu, Xi, Liu, Xuezhi, Xu, Jihuan
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Applied sciences; Devices using thermal energy; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electricity generation; Energy; Energy. Thermal use of fuels; Equipments, installations and applications; Exact sciences and technology; Experiment; Fabrication; Heat pumps; Loop heat pipe; Natural energy; Photoelectric conversion; Photovoltaic cells; Photovoltaic conversion; Photovoltaic/thermal; Solar cells. Photoelectrochemical cells; Solar energy; Solar thermal conversion; Temperature effects
• ISSN: 0038-092X; 1471-1257; 1471-1257
• DOI: 10.1016/j.solener.2013.09.022

•We apply a novel loop heat pipe into photovoltaic/thermal (PV/T) concept.•PV panel performs better with a coated aluminium-alloy sheet as its baseboard.•We evaluated the system in outdoor weather conditions for about one week.•This system performs better than some conventional solar/air energy systems.•Simple analysis of economic and environmental benefits is made. In this paper, a novel solar photovoltaic/loop-heat-pipe (PV/LHP) module-based heat pump system was designed and fabricated for both electricity and hot water generation. A coated aluminium-alloy (Al-alloy) sheet was applied as the baseboard of PV cells for enhanced heat dissipation to the surroundings, which was characterised by a series of laboratory-controlled conditions over the conventional Tedlar–Polyester–Tedlar (TPT) baseboard. The whole prototype system was subsequently evaluated in outdoor weather conditions throughout a consecutive period for about one week. Impact of several external parameters to the PV panel with different baseboards was discussed and the results showed that weaker incident radiation, lower air temperature, higher wind speed, and ground mounting solution, were propitious to the PV electrical performance. Given the specific indoor testing conditions, temperature of the Al-alloy based PV cells was observed at about 62.4°C, which was 5.2°C lower than that of the TPT based PV cells, and its corresponding PV efficiency was about 9.18%, nearly 0.26% higher than the TPT based type. During the outdoor testing, the mean daily electrical, thermal and overall energetic and exergetic efficiencies of the PV/LHP module were measured at 9.13%, 39.25%, 48.37% and 15.02% respectively. The basic-thermal system performance coefficient (COPth) was found at 5.51 and the advanced system performance coefficient (COPPV/T) was nearly 8.71. A simple comparison was also conducted between the PV/LHP based heat-pump system and those conventional solar/air energy systems, which indicated that this advanced system harvests larger amount of solar energy and therefore enables enhanced solar efficiency and system performance. Basic analysis into the economic and environmental benefits of this prototype system further demonstrated such technology will be competitive in the future energy supply industry with a payback period of 16 (9) years and a life-cycle carbon reduction of 12.06 (2.94) tons in Shanghai (London).