A process for liquefying a process gas that includes introducing a heat transfer fluid into an active magnetic regenerative refrigerator apparatus that comprises a single stage comprising dual multilayer regenerators located axially opposite to each other.

A method for operating a caloric heat pump system includes changing a cycle frequency at which a field of a field generator is applied to caloric material in the caloric heat pump system. The method also includes adjusting a speed of a hot side fan in response to the cycle frequency change and adjusting a speed of a cold side fan in response to the cycle frequency change. A respective one of three separate control loops changes the cycle frequency, adjusts the speed of the hot side fan, and adjusts the speed of the cold side fan.

A method for operating a caloric heat pump system includes changing a cycle frequency at which a field of a field generator is applied to caloric material in the caloric heat pump system. The method also includes adjusting a speed of a hot side fan in response to the cycle frequency change and adjusting a speed of a cold side fan in response to the cycle frequency change. A respective one of three separate control loops changes the cycle frequency, adjusts the speed of the hot side fan, and adjusts the speed of the cold side fan.

A heat transfer system (310) is disclosed that includes a first electrocaloric module (62) comprising a first electrocaloric material, a first high-side voltage electrode, and a first low-side voltage electrode, arranged to impart an electric field to the electrocaloric material. The system also includes a second electrocaloric module (64) comprising a second electrocaloric material, a second high-side voltage electrode, and a second low-side voltage electrode, arranged to impart an electric field to the electrocaloric material. A bi-directional power transfer circuit (60) is also included arranged to alternately transfer power from the electrodes of the first electrocaloric module (62) to the second electrocaloric module (64), and from the electrodes of the second electrocaloric module (64) to the first electrocaloric module (62).

A heat transfer system (310) is disclosed that includes a first electrocaloric module (62) comprising a first electrocaloric material, a first high-side voltage electrode, and a first low-side voltage electrode, arranged to impart an electric field to the electrocaloric material. The system also includes a second electrocaloric module (64) comprising a second electrocaloric material, a second high-side voltage electrode, and a second low-side voltage electrode, arranged to impart an electric field to the electrocaloric material. A bi-directional power transfer circuit (60) is also included arranged to alternately transfer power from the electrodes of the first electrocaloric module (62) to the second electrocaloric module (64), and from the electrodes of the second electrocaloric module (64) to the first electrocaloric module (62).

Systems and/or methods can provide for solid-state refrigeration below 1 degree Kelvin. By applying a simple sequence of ac electrical signals to a gated semiconductor device, electrons are cooled in a refrigeration sequence that, in turn, provides cooling directly to the heat load of interest. Electrons in a single subband of a semiconductor quantum well are expanded adiabatically into several subbands, resulting in a temperature drop. Repeated application of this cycle at MHz-GHz frequencies results in a significant cooling power. The anticipated cooling powers can compete with today's standard cryogenic system, the dilution refrigerator, which represents the market standard for achieving cryogenic temperatures.

Systems and/or methods can provide for solid-state refrigeration below 1 degree Kelvin. By applying a simple sequence of ac electrical signals to a gated semiconductor device, electrons are cooled in a refrigeration sequence that, in turn, provides cooling directly to the heat load of interest. Electrons in a single subband of a semiconductor quantum well are expanded adiabatically into several subbands, resulting in a temperature drop. Repeated application of this cycle at MHz-GHz frequencies results in a significant cooling power. The anticipated cooling powers can compete with today's standard cryogenic system, the dilution refrigerator, which represents the market standard for achieving cryogenic temperatures.

A thermoacoustic device includes a stage coupled to a bar, wherein the stage includes a first heating component on a first terminus of the stage. The stage further includes a first cooling component on a second terminus of the stage. A thermal conductivity of the stage is higher than a thermal conductivity of the bar. A heat capacity of the stage is higher than a heat capacity of the bar.

A solid-state refrigeration apparatus includes a solid cooling structure, first and second heat exchangers, a heating medium circuit, a reciprocating conveying mechanism, and a thermal storage section. The solid cooling portion includes a solid refrigerant substance, an internal channel where the solid refrigerant substance is disposed, and an induction section configured to cause the solid refrigerant substance to produce a caloric effect. The heating medium circuit is connected to the first and second heat exchangers, and the internal channel. The heating medium heated by the solid cooling portion dissipates heat in the first heat exchanger and the heating medium cooled by the solid cooling portion absorbs heat in the second heat exchanger a heat application operation. Frost on the second heat exchanger is melted using the heat stored in the thermal storage section in a defrosting operation. The thermal storage section stores heat in the heat application operation.

A solid-state refrigeration apparatus includes a solid cooling structure, first and second heat exchangers, a heating medium circuit, a reciprocating conveying mechanism, and a thermal storage section. The solid cooling portion includes a solid refrigerant substance, an internal channel where the solid refrigerant substance is disposed, and an induction section configured to cause the solid refrigerant substance to produce a caloric effect. The heating medium circuit is connected to the first and second heat exchangers, and the internal channel. The heating medium heated by the solid cooling portion dissipates heat in the first heat exchanger and the heating medium cooled by the solid cooling portion absorbs heat in the second heat exchanger a heat application operation. Frost on the second heat exchanger is melted using the heat stored in the thermal storage section in a defrosting operation. The thermal storage section stores heat in the heat application operation.