An open-loop hybrid photovoltaic solar thermal evacuated tube energy system: A new configuration to enhance techno economic of conventional photovoltaic solar thermal system

Abstract

One inherent problem of the conventional hybrid photovoltaic solar thermal system is the gradual loss of module power efficiency with low energy harvesting due to steady increase in module temperature with repeated circulation of the cooling water as a result of its closed loop configuration. This poor energy harvesting couple with high initial investment has made investment in this technology unattractive. This study proposes an enhanced hybridisation of the Photovoltaic Solar Thermal System collector with an evacuated tube based on an open-loop cooling configuration and unique flow control strategy. The aim is to improve cooling of solar panel leading to higher energy harvesting and utilisation that improves economic viability that will promote faster adoption. A numerical model is formulated using TRNSYS 18 software to assess the techno economics of the hybrid system. The model is validated using the verification and experimental methods. Overall, the findings show that the enhanced hybridisation and flow control strategy has resulted in higher annual renewable power generation and utilisation by 10 % than the basic hybrid Photovoltaic Solar Thermal system. This has resulted in significant economic savings, cutting operating expenses by 48 %. The ability to tailor the intended use of the system to meet with hot water and electrical power demand of different residential building is another attribute of proposed system that improve its energy harvesting reducing it payback period and doubling it economic benefit hence promoting it fast adaptability.