Feasibility Study of Using Domestic Solar Hot Water Systems as Alternative to Reduce the Electricity Peak Demand in Brazil

Abstract

Brazil is one of the few countries where the water heating for bath is performed by using electric showerheads. The widespread use of these devices is the mainly responsible for the high peak on the electricity demand of the residential sector, observed between 18:00 and 21:00 hours. As a consequence of that, costs and service quality are undermined, affecting consumers and the electricity sector in general. In attempt to deal with this issue, solar hot water systems have been proposed as an option to reduce the electricity consumption of the showerheads. However, despite of the high incidence of solar radiation on the Brazilian territory indicates a significant economy, currently there is no technical assessment quantifying the economic benefits on the region. The present study estimates the economic impacts resulting by the deployment of solar hot water systems in Brazilian households. Hence, the feasibility study allows assessing the potential of solar water heating as alternative to reduce the peak on the electricity demand in Brazil. In order to perform the proposed analysis, long-term performance simulations were performed on an hourly basis using the TRNSYS software as computational tool and typical meteorological year (TMY) files as input data. The TRNSYS component (Type 45) relating the solar water heating equipment had been experimentally validated, whereas the weather data was obtained from the SWERA database. Also, a time dependent profile of the heating demand is considered, according the measurements collected in previous studies. The thermal performance is evaluated in terms of solar fraction. On the other hand, the economic impacts are quantified in terms of three criteria for economic feasibility, such as payback period, internal rate of return and life cycle savings. In order to explore the benefits arising from different policies, four tariff scenarios are considered. The economic evaluation is positive over all scenarios analyzed, showing savings for both, the consumers and the electricity sector. The results of this analysis can be used as support tool for target setting the adoption or spread the use solar water heaters, or even to create policies for its diffusion.

An analysis of the economic viability and greenhouse gas emissions reductions resulting from the use of solar water heaters in a typical Brazilian dwelling

“…This study is consistent with other studies conducted in Brazil, that demonstrate the economic viability of solar water heaters, with capital payback between 1 and 10 years (Oliveira et al, 2008;Naspolini and Ruther, 2012;Martins et al, 2012;Passos et al, 2014). Based on the values presented above, the capital payback time can vary greatly depending on the local parameters, such as incident solar radiation, cost of solar heater and price of electric energy tariff.…”

Energy performance enhancement of a collective hot water production process equipped with a centralized storage tank

“…The authors used hourly dynamic simulations to decrease the electric energy peak demand due to the extensive use of electric showerheads (ESH ) in households. Moreover, Passos et al [15] studied the feasibility of using domestic SWHs as alternative solution to decrease the electricity peak demand in Brazil.…”

“…In this case, the flow rate of the pumps can be fixed or variable (match-flow system). In fact, the system stops the circulation if the temperature of the storage tank or the temperature of the collector is higher than the respective maximum safety temperatures [15].…”

Towards Systems-Oriented Energy Solutions: A Multilevel Analysis of a Low-Income Energy Efficiency Program in Brazil

“…Although electric showerheads are low-cost devices, they account for 20% of the residential energy consumption in a household [65], which therefore accounts for a considerable part of the household expenditure on electricity. Moreover, these devices present a significant peak load problem for energy utilities because they account for 43% of the consumption peak between 6 and 9 pm [66]. For these reasons, in low-income households, a heat recovery system for electric showerheads has been proposed as a solution for increasing energy efficiency and decreasing the negative consequences of high peak demand on the quality of the electricity supply at peak time.…”