Development of small temperature difference gas hydrate power generation system using scroll expansion machine

Abstract

Gas hydrate has gas molecules in cage-like water molecules, large pressure difference by the change of state is obtained to a small temperature change. This study propose a power generation system that utilizes unique state change characteristics by thermal cycle of gas hydrate. The required energy for operation of the proposed system is only heat, and the heat source use the waste heat (high temperature heat source) of individual houses and the outside air temperature (low temperature heat source) in the cold district. We developed a trial power generation system which adopts scroll expander for actuator. It uses CO₂ in consideration of safety and convenience. CO₂ hydrate is generated from the contact part between water and CO₂ gas. Therefore, investigate the change in overall efficiency by changing the installation method (contact area) of the reactor in the trial power generation system. As a result, it is expected that the power generation efficiency will reach 11.8% by properly installing the reactor.