With the Internet of Things expanding to more locations across our planet, power becomes the main factor affecting device longevity. There is a need for more novel energy harvesting systems that are able to power remote devices for sustained periods. This publication presents one such device. Based on a novel actuator that utilises off-the-shelf gas mixtures to generate a variable force from temperature change, this publication presents a device capable of generating up to 150mJper diurnal temperature cycle; this is enough electrical energy to send up to three LoRaWAN transmissions per day using slowly changing environmental temperatures.