Energy harvester for a wireless sensor in a boiler environment

Wireless sensors have become a focus of study in the field of measurement technologies. The power supply of many wireless sensors is based on batteries or external power sources. However, there is increasing interest in finding solutions where the batteries can be leaved away and the power for the wireless sensors is produced from the environment in which the sensors operate. The technologies required are called energy harvesting or scavenging technologies.This paper introduces the principles, modeling and a practical implementation of a self-powering solution for a wireless sensor for energy boilers or other hot reactor vessels. With the aid of energy solution introduced, the wireless sensor can operate autonomously without any batteries. One of the design targets in this work was that the top part of harvester’s mechanics must fit to the opening or assembly tube of diameter less than 15 mm in the boiler wall reserved for standard instrument assemblies. So the top of harvester collects and conducts thermal energy to element generating electricity from it. The harvester and further the measuring and communication electronics are mounted outside the hot area.The harvester solution introduced in the paper can produce about 114 mW power, when top of harvester mechanics was inserted to the test oven heated to temperature of +500 °C. The sensor function or type is not defined nor limited in this study. The electric energy generated by harvester can be used to power, for example, temperature, heat flux, flow, vibration or other little energy needing sensors.