Energy management system design oriented for energy cost optimization in electric water heaters

Energy consumption in homes with Electric Water Heaters accounts currently means up to 30% of the total energy consumption. Their low cost and easy installation are priority factors for users, despite the high cost of electricity consumption in these equipments. The aim of this paper is to develop a modular and low cost Energy Management System which minimizes the electricity bill without compromising the level of comfort. An algorithm is developed that estimates the appropriate hours of operation of the Electric Water Heater that guarantees comfort based on the consumption habits, the monitorization of temperatures and dynamic electricity prices. Another of the functionalities implemented in the Energy Management System is to manage the instantaneous power demanded at homes by disconnecting certain non-priority loads when the maximum contracted power is going to be exceded and to reduce the fixed cost of the bill. The Energy Management System has been installed in a home and results of cost optimization are provided. The device uses free distribution software with Raspberry/NodeMCU platforms and allows monitoring and control of the system through a web page.