A comparative analysis of thermosolar and photovoltaic systems for meeting residential hot water demands

Abstract

Electric Shower Heads (ESHs) are commonly employed for bathing In Brazil and other developing nations, given their installation and maintenance affordability. However, these devices consume a significant amount of electricity to heat the water, leading to higher household electricity bills. Renewable alternatives like thermal and solar photovoltaic energy could be used to provide hot water solutions for residential buildings. While other energy sources e.g., piped natural gas (NG) or liquefied petroleum gas (LPG), can also be used to heat water, their practicality of use is limited in Brazil. In this paper, we study the cost-effectiveness of residential thermosolar systems versus electric shower heating systems. Here we studied residential buildings equipped with self-generation photovoltaic systems connected to the electricity distribution grid operating under Brazil's Distributed Generation (DG) rules, compared to residences without these systems. Our economic analyses employed the Payback, Net Present Value (NPV), Internal Rate of Return (IRR), and Levelized Cost of Electricity (LCOE). The findings indicate that the most economically viable option for residential units was using ESHs together with photovoltaic generation systems. This resulted in an NPV of US$ 1078.2, an IRR of 13.1 % and an LCOE of 0.0782 US$/kWh over 25 years.