A system is provided. The system includes at least two heat exchangers that are alternatively cooled by an outlet medium. The system also includes a cooling circuit that provides a cooling medium to the at least two heat exchangers. The cooling circuit provides the cooling medium to a first heat exchanger of the at least two heat exchangers in accordance with a first mode. The cooling circuit provide the cooling medium to a second heat exchanger of the at least two heat exchangers in accordance with a second mode.

A heat generating device includes a container, a heat generating element, and a heater. A hydrogen-based gas contributing to heat generation is introduced into the container. The heat generating element is provided inside the container. The heater is configured to heat the heat generating element. The heat generating element includes a base made of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on a surface of the base. The multilayer film having a stacking configuration of: a first layer that is made of a hydrogen storage metal or a hydrogen storage alloy, and a second layer that is made of a hydrogen storage metal, a hydrogen storage alloy, or ceramics different from that of the first layer. The first layer and the second layer have a layer shape with a thickness of less than 1000 nm.

A heat generating device includes a container, a heat generating element, and a heater. A hydrogen-based gas contributing to heat generation is introduced into the container. The heat generating element is provided inside the container. The heater is configured to heat the heat generating element. The heat generating element includes a base made of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on a surface of the base. The multilayer film having a stacking configuration of: a first layer that is made of a hydrogen storage metal or a hydrogen storage alloy, and a second layer that is made of a hydrogen storage metal, a hydrogen storage alloy, or ceramics different from that of the first layer. The first layer and the second layer have a layer shape with a thickness of less than 1000 nm.

An operating method of a heat-storage system includes the steps of executing a first operating mode to supply heat to a first hydrogen storage alloy in a first tank, to cause movement of hydrogen from the first hydrogen storage alloy in the first tank to a second hydrogen storage alloy in a second tank, the second hydrogen storage alloy being different from the first hydrogen storage alloy in dissociation pressure characteristic with respect to an alloy temperature, and executing a second operating mode to supply cold of outside air to the first hydrogen storage alloy, to cause movement of hydrogen from the second hydrogen storage alloy in the second tank to the first hydrogen storage alloy in the first tank, in which the step of executing the first operating mode includes a step of storing a temperature generated in the second hydrogen storage alloy in a heat storage device.

An operating method of a heat-storage system includes the steps of executing a first operating mode to supply heat to a first hydrogen storage alloy in a first tank, to cause movement of hydrogen from the first hydrogen storage alloy in the first tank to a second hydrogen storage alloy in a second tank, the second hydrogen storage alloy being different from the first hydrogen storage alloy in dissociation pressure characteristic with respect to an alloy temperature, and executing a second operating mode to supply cold of outside air to the first hydrogen storage alloy, to cause movement of hydrogen from the second hydrogen storage alloy in the second tank to the first hydrogen storage alloy in the first tank, in which the step of executing the first operating mode includes a step of storing a temperature generated in the second hydrogen storage alloy in a heat storage device.

An air changeover system for a metal hydride heat pump is disclosed. The system includes metal hydride reactor modules aligned and separated by a partition; a shell containing the reactor modules, the shell is compartmentalized to define separate insulated chambers for each of the reactor modules; and a bearing assembly supporting the modules at a location about the partition, wherein the bearing assembly rotates said modules about an axis during the absorption and the desorption mode. The system reduces thermal inertia and pressure drop in the heat transfer medium while flowing through the heat pump, to enhance the performance and conserve energy.

An air changeover system for a metal hydride heat pump is disclosed. The system includes metal hydride reactor modules aligned and separated by a partition; a shell containing the reactor modules, the shell is compartmentalized to define separate insulated chambers for each of the reactor modules; and a bearing assembly supporting the modules at a location about the partition, wherein the bearing assembly rotates said modules about an axis during the absorption and the desorption mode. The system reduces thermal inertia and pressure drop in the heat transfer medium while flowing through the heat pump, to enhance the performance and conserve energy.

The community system includes a hydrogen source, a hydrogen storage, an FC power generating facility, a house group that uses electric power supplied from the FC power generating facility and hydrogen supplied from at least one of the hydrogen source and the hydrogen storage, and a management system that manages hydrogen in the community system. Each house in the house group is provided with a cooking-related appliance that uses hydrogen.

The community system includes a hydrogen source, a hydrogen storage, an FC power generating facility, a house group that uses electric power supplied from the FC power generating facility and hydrogen supplied from at least one of the hydrogen source and the hydrogen storage, and a management system that manages hydrogen in the community system. Each house in the house group is provided with a cooking-related appliance that uses hydrogen.

Envisaged is an exhaust gas heat recovery system comprising a heat pump, a mixer and a flow regulating means. The heat pump is configured to pump heat from a refrigerant. The heat pump has an inlet and an outlet wherein the exhaust gas stream leaving the outlet is split into two streams: a stream rejected to atmosphere and a recirculating exhaust stream re-circulated back to the heat pump. The mixer is provided at the inlet of the heat pump to mix an inlet exhaust stream with the recirculating exhaust gas stream to get a resultant exhaust stream at an intermediate temperature of the two streams. The flow regulating means is adapted to compress the recirculating exhaust stream.