Smart electric water heaters: a system architecture proposal for scalable IoT

Abstract

Energy and water are scarce resources in South Africa, and the management thereof is receiving increased attention. One rare place where energy and water coincide is in water heaters, which consume over 30% of household energy in South Africa and collectively pass over 500 billion litres of water annually. These resource-hungry devices are not well managed and tend to be physically inaccessible and difficult to understand for users. The advent of wireless and cloud computing technology brought expectations of simple management of a multitude of devices and the so-called Internet of Things. A few solutions have been proposed for remote water heater management, but these are not scalable, and have not been benchmarked for scalability above tens of units. This paper proposes an end-to-end architecture to monitor and control EWHs based on MQTT, and specific emphasis is placed on the technologies suitable for large-scale cross-domain interoperability. The performance of the system with 10,000 connections and the results of a pilot deployment are presented.