Design of Low-cost Thermoelectric Generators for Autonomous Sensors and Actuators in Domestic Hot Water Systems

Roy, Geoffrey [UCL] Ségolène Vannerem [UCL] Marchal-Marchant, Valentin [UCL] Poncelet, Olivier [UCL] Van Der Rest, Camille [UCL] Jacques, Pascal [UCL]

The fast emergence of the “Internet of Things” (IoT) will lead to a massive dissemination of billions of connected devices in the world during the coming years. Especially in the domestic hot water system sector’s, smart devices such as smart thermostat or intelligent thermostatic radiator valve can improve comfort while decreasing energy consumption. The main drawback of these systems is their energy dependency to batteries. This limits the system lifetime and its recyclability. An alternative to batteries is the use of energy harvesting systems that can harvest heat from the hot water and convert it in electricity using thermoelectricity. The proof-of-concept has been realised with off-the-shell component such as commercial Peltier cooler as generator limiting the performances of the system. Specific thermoelectric generators have also been designed using micro-fabrication techniques, but this solution remains costly. The present work follows a global design approach to develop a high-performance thermoelectric system for autonomous sensors and actuators in domestic hot water systems. By designing the whole system, mainly the heat sink and the thermoelectric generator, there are more degrees of freedom for optimising the performances. Moreover, the cost of the system can be dramatically decreased owing to the use of a low-cost thermoelectric materials based on earth-abundant elements, the Fe2VAl compound. The original design approach will be presented and comforted by the experimental characterisation of a prototype on a domestic hot water system test bench.