Energetic and economic optimisation of a novel hybrid pv-thermal system for domestic combined heating and power

Abstract

Techno-economic performance calculations have been performed for a hybrid photovoltaic-thermal (PVT) collector design, featuring a novel polycarbonate flat-box absorber-exchanger configuration, integrated into a solar combined heat and power (S-CHP) system for the simultaneous provision of domestic hot water (DHW), space heating and power. The demands for electricity (including for lighting, cooling, and other home appliances), DHW and space heating from a single-family house located in two different climates, Zaragoza (Spain) and London (UK), were estimated and considered together with the local climate conditions in the S-CHP system performance analysis. The S-CHP system model used in this analysis includes the governing equations of the PVT unit, a hot-water storage tank, a water pump and a tank bypass. The capital (investment) cost of the system and the utility (electricity, natural gas) costs are also integrated into the model. The PVT array area and storage tank volume were sized to meet a minimum requirement for thermal energy demand coverage at each geographical location, and a seasonal optimisation of the collector flow-rate was performed to minimise the levelised production cost (LPC) of electrical and thermal energy and the levelised emissions displacement cost (LEDC). The results show that the S-CHP system optimised for Zaragoza with an array of 14 PVT collectors (covering 22 m2, with a 3.4-kWe peak electrical power rating) can provide 77% of the total household thermal demand and 145% of its electrical demand, averaged over the four seasons, with the surplus electricity exported to the grid, generating additional income. With the system optimised for London and an array of 17 PVT collectors (covering 26 m2, with a 4.1-kWe peak electrical power rating), the system provides 55% and 153% of the household thermal and electrical demands, respectively.