Estudo técnico-econômico de sistemas solares combinados a bomba de calor para aquecimento de água

Abstract

This paper analyzes the technical-economic feasibility and the performance of solar water heating systems, applied to large scale domestic consumption in the city of Natal-RN. This analysis aims to stimulate the harnessing of solar resource as thermal energy, as a sustainable alternative to electric heating. Two conventional configurations are studied, as well as two configurations combined with heat pumps. The conventional systems differ from each other in terms of thermal storage volume, by which the first system contains a single storage tank, whose volume varies according to the area of installed solar collectors, whereas the second system uses two separate storage tanks with fixed volume. The systems associated with heat pumps are similar to the second case, and differ from each other in that one of them uses an air-to-water heat pump as an auxiliary heater, while the other relies on a water-to-water heat pump and a bypass valve to connect its two storage tanks. Weather data pertaining to the studied location is implemented in the format of a typical meteorological year (TMY). A methodology for mathematical modeling and transient numerical simulation is applied using the MATLAB software. The economical analysis is based on the P1 − P2 method, applied through MATLAB. Its goal is to estimate the net return provided to the user by each system, throughout its life-cycle. According to the results of both energy efficiency and financial return, all of the configurations analyzed in this paper prove advantageous. For applications with a reduced area of solar collectors, the combined system using an air-to-water heat pump is optimal, whereas the first conventional system shows the best cost-benefit ratio in cases where a larger area of collectors may be installed.