Electric power control of a power generator using dissociation expansion of a gas hydrate

The unique dissociation expansion characteristics of gas hydrates allow a large pressure difference to be obtained from a small change in temperature. This suggests that a clean actuator system may be built that can use low temperature heat from the nighttime air and high temperature heat from daytime solar radiation or other sources. This study proposed a generator that could operate using a small temperature difference, by leveraging the change of state of a gas hydrate. The dynamic characteristics of an alternating current power supply from a gas-hydrate power-generation system (GHGS) have not previously been reported. The objective of the study was to achieve an electric power supply of acceptable quality (frequency and voltage) from a GHGS while tracking demand. A pressure regulating valve under P-I control was used to adjust the supply of high-pressure dissociated gas to the actuator. As the GHGS was of the batch type, a hybrid system including a conventional gas-powered generator was also investigated. A numerical analysis showed that, when a flywheel with an inertia constant of 6.9 kg/m2 was installed, the hybrid system was able to provide a stable electricity supply for an individual house.