A refrigeration system can include a main flow circuit configured to flow a refrigerant therethrough and a heat input disposed in the main flow circuit and configured to receive heat and transfer the heat to the refrigerant in the main flow circuit to output heated refrigerant flow. The system can include a passive pump disposed in the main flow circuit downstream of the heat input configured to receive the heated refrigerant flow from the heat input and to use the heated refrigerant flow to generate a vacuum at a pump port and a condenser disposed in the main flow circuit downstream of the passive pump for receiving flow from the passive pump. The condenser can be configured to receive heat from the heated refrigerant flow and reject heat to cool the heated refrigerant flow to output partially cooled refrigerant flow. An outlet of the condenser can be upstream of the heat input.

A refrigeration system can include a main flow circuit configured to flow a refrigerant therethrough and a heat input disposed in the main flow circuit and configured to receive heat and transfer the heat to the refrigerant in the main flow circuit to output heated refrigerant flow. The system can include a passive pump disposed in the main flow circuit downstream of the heat input configured to receive the heated refrigerant flow from the heat input and to use the heated refrigerant flow to generate a vacuum at a pump port and a condenser disposed in the main flow circuit downstream of the passive pump for receiving flow from the passive pump. The condenser can be configured to receive heat from the heated refrigerant flow and reject heat to cool the heated refrigerant flow to output partially cooled refrigerant flow. An outlet of the condenser can be upstream of the heat input.

A thermal management system for a gas turbine engine includes a primary vapor compression system including a primary evaporator defining thermal communication between a primary refrigerant and a flow of fuel to cool the fuel. A boost vapor compression system includes a boost heat exchanger defining thermal communication between the primary refrigerant. A boost refrigerant cools the primary refrigerant and a boost condenser in thermal communication with an air stream cools the boost refrigerant.

A thermal management system for a gas turbine engine includes a primary vapor compression system including a primary evaporator defining thermal communication between a primary refrigerant and a flow of fuel to cool the fuel. A boost vapor compression system includes a boost heat exchanger defining thermal communication between the primary refrigerant. A boost refrigerant cools the primary refrigerant and a boost condenser in thermal communication with an air stream cools the boost refrigerant.

A heating and cooling system powered by renewable energy and assisted with geothermal energy includes a solar cycling unit, a supercritical carbon dioxide (S—CO.sub.2) unit, and a refrigerant cycling unit. Solar energy obtained at the solar cycling unit may be used to power the S—CO.sub.2 cycling unit. To do so, the solar cycling unit utilizes a solar collector, a thermal energy storage, and a heat exchanger along with a first working fluid which is preferably molten salt or Therminol. Next, the energy generated at the S—CO.sub.2 cycling unit, which preferably circulates S—CO.sub.2 as a second working fluid, may be used to operate the refrigerant cycling unit. In the refrigerant cycling unit, Tetrafluroethene is preferably used as the third working fluid to produce required cooling effects. Additionally, geothermal heat exchangers may be integrated into the system for use during varying weather conditions.

A working medium for a heat cycle includes HFO-1123, HFC-32, and HFO-1234ze. These three components HFO-1123, HFC-32, and HFO-1234ze are present as principal components in a mixture state.

A working medium for a heat cycle includes HFO-1123, HFC-32, and HFO-1234ze. These three components HFO-1123, HFC-32, and HFO-1234ze are present as principal components in a mixture state.

A refrigeration and/or heat transfer device includes a heating section and cooling section, a release member, and a one-way check valve affixed together in a continuous loop so working fluid may flow in one direction therein. The heating section absorbs heat and transfers such heat to the working fluid, thereby heating, expanding and increasing pressure upon the working fluid therein. The pressurized working fluid is released in a regulated manner from the heating section to the cooling section, thereby carrying the heat away. The released working fluid cools and transfers its heat to the surroundings within the cooling section. As released working fluid enters the cooling section, such fluid displaces already cooled working fluid, pushing such fluid through the one-way check valve back into the heating section to absorb heat. The working fluid may undergo a phase change or remain in a single phase throughout to enhance heat transfer.

A refrigeration and/or heat transfer device includes a heating section and cooling section, a release member, and a one-way check valve affixed together in a continuous loop so working fluid may flow in one direction therein. The heating section absorbs heat and transfers such heat to the working fluid, thereby heating, expanding and increasing pressure upon the working fluid therein. The pressurized working fluid is released in a regulated manner from the heating section to the cooling section, thereby carrying the heat away. The released working fluid cools and transfers its heat to the surroundings within the cooling section. As released working fluid enters the cooling section, such fluid displaces already cooled working fluid, pushing such fluid through the one-way check valve back into the heating section to absorb heat. The working fluid may undergo a phase change or remain in a single phase throughout to enhance heat transfer.

An enhanced vapor injection air conditioning system (100) is provided and includes: a vapor injection compressor (1), a direction switching assembly (2), a first outdoor heat exchanger (3), a second outdoor heat exchanger (4) including first and second heat-exchange flow passages (41, 42), and an auxiliary electronic expansion valve assembly. A main electronic expansion valve assembly is connected between a first end (411) of the first heat-exchange flow passage and a second end (32) of the first outdoor heat exchanger. The auxiliary electronic expansion valve assembly has a first end connected with an inlet of the second heat-exchange flow passage (42), and a second end connected to a second end (412) of the first heat-exchange flow passage or between the main electronic expansion valve assembly and the first heat-exchange flow passage (41). A ratio DB of a sum of a caliber of the main electronic expansion valve assembly to that of the auxiliary electronic expansion valve assembly has a value range of 1≦DB≦7.