Automation and energy optimization of a domestic solar heating unit

This paper presents a domestic solar heating unit with high level of automation, specially designed to reduce energy consumption in Brazilian residences, where almost 25% of electrical energy is spent to heat water for bathing. The system is composed basically by solar plates, a boiler and an electric shower. Automatic valves and power controllers are used to regulate the temperature and flow during the bath. A microcontroller is responsible for defining optimal set-points of the system aiming energy optimization, minimizing the waste of water, and increasing comfort for the user. A mathematical model was developed and a prototype was used to validate it. The proposed system proved to be economically viable, saving expressive quantities of electrical energy and water if compared to traditional systems.