Development of a small temperature difference generator by using the dissociation and expansion characteristics of a CO2 hydrate

The introduction of distributed generation systems using renewable energy has been advancing in Japan mainly driven by the influence of the Fukushima Daiichi nuclear accident. In this work, a distributed energy system which exploits the unique state-change property of a CO2 hydrate through a heat cycle is proposed. The proposed system is environmentally friendly because no fossil fuel is burnt and no carbon dioxide is emitted to the atmosphere. Furthermore, the inputs of heat energy are supplied by renewable sources such as the outdoor cold air and the geothermal heat, as cold and hot mediums, respectively. In this study, we determined the characteristics of the output of the proposed generation system by experiments performed in a prototype constructed in our laboratory. As a result, a maximum power output of 30W and a maximum efficiency of 2.15% were obtained.