Techno-economic assessment and environmental impact of photovoltaic and conventional solar water heating systems in cold climates

Nowadays, solar energy is a viable solution for producing domestic hot water and reducing greenhouse gas emissions in remote regions that rely on fossil fuels for this purpose. In this context, the current research work compares the performance of flat-plate, evacuated tube, and photovoltaic solar water heating systems. The objective is to determine which solar water heater is the most efficient from a techno-economic and environmental point of view. The analysis of the energy, economic and environmental performances of these three systems was carried out using energy simulation tools (MATLAB and TRNSYS) and a life cycle analysis tool (SimaPro). Despite the low annual thermal efficiency of the PV water heater, the results show that it is more efficient from a techno-economic point of view since its levelized cost of heat (LCOH) varies between 0.14 and 0.23 $CAD/kWh. Although the photovoltaic water heater is carbon neutral compared to fuel-fired water heaters, the life cycle analysis reveals that it has a higher environmental impact than its solar thermal counterparts. Specifically, it emits three times more CO2 during its life cycle, equivalent to 4.3 tCO2.