An air-conditioning apparatus includes an outdoor heat exchanger. The outdoor heat exchanger includes a first heat exchanger and a second heat exchanger. A controller performs a heating operation and a heating-defrosting operation, in which one of the first heat exchanger and the second heat exchanger functions as an evaporator, an other one the first heat exchanger and the second heat exchanger functions as a condenser. When a temperature of the indoor heat exchanger by a temperature detection unit is treated as a first temperature, and a temperature of the indoor heat exchanger by the temperature detection unit is treated as a second temperature, the controller reduces a rotation speed of an indoor fan in a case where the second temperature is lower than the first temperature and where a difference between the first temperature and the second temperature is greater than or equal to a first setting value.

Systems and methods for implementing ejector refrigeration cycles with cascaded evaporation stages that utilize a pump to optimize operation of the ejector and eliminate the need for a compressor between the evaporation stages.

Systems and methods for implementing ejector refrigeration cycles with cascaded evaporation stages that utilize a pump to optimize operation of the ejector and eliminate the need for a compressor between the evaporation stages.

A dual reclaim coil with a smart control application is provided that allows the refrigerant inlet to the HVAC unit switch between the two sides of the condenser is aimed to use the high temperature and pressure of the condenser/gas cooler outlet while a CO.sub.2 refrigerant system is operating above critical point. This occurs in hot ambient conditions, when the need for heating in the space is not as great as in the wintertime and the available heat at the condenser/gas cooler's outlet is sufficient to satisfy the heating load. This also mitigates space overcooling, while increasing the CO.sub.2 transcritical system's efficiency by subcooling the refrigerant for applications involving dehumidification HVAC systems which often results in a phenomenon called “overcooling” during the dehumidification season.

A dual reclaim coil with a smart control application is provided that allows the refrigerant inlet to the HVAC unit switch between the two sides of the condenser is aimed to use the high temperature and pressure of the condenser/gas cooler outlet while a CO.sub.2 refrigerant system is operating above critical point. This occurs in hot ambient conditions, when the need for heating in the space is not as great as in the wintertime and the available heat at the condenser/gas cooler's outlet is sufficient to satisfy the heating load. This also mitigates space overcooling, while increasing the CO.sub.2 transcritical system's efficiency by subcooling the refrigerant for applications involving dehumidification HVAC systems which often results in a phenomenon called “overcooling” during the dehumidification season.

A method for defrosting an external heat exchanger, operated as an air heat pump evaporator, of a cooling system for a motor vehicle. The cooling system includes a refrigerant compressor connected to a primary and secondary section; an external heat exchanger; an evaporator; a heating register; a primary section valve which is closed in the air heat pump operation; and a secondary section valve which is open in the air heat pump operation. The method includes closing of the secondary section valve; opening of the primary section valve, so that refrigerant flows directly from the refrigerant compressor to the external heat exchanger; and setting an inlet-side pressure level of the refrigerant on the external heat exchanger to a target pressure which corresponds to a condensation temperature (Tkond) of the refrigerant in the range: 2° C. ≤ Tkond ≤ 20° C., in particular 4° C. ≤ Tkond ≤ 10° C.

A recreational vehicle air conditioning system supports multiple recreational vehicle air conditioning units having closed air conditioning circuits and a controller that is electronically coupled to each of the recreational vehicle air conditioning units to control each of the closed air conditioning circuits to regulate an overall power consumption of the multiple recreational vehicle air conditioning units. A recreational vehicle air conditioning system may also support multiple recreational vehicle air conditioning units where a refrigerant line set is coupled between the recreational vehicle air conditioning units such that a compressor in one of the recreational vehicle air conditioning units is capable of supplying refrigerant to the evaporators of the multiple recreational vehicle air conditioning units, and such that valves coupled in series with each of the evaporators may be regulated to control cooling by each recreational vehicle air conditioning unit.

The disclosed invention is a relay switch that is capable of controlling the sequence in which a multi-unit heat pump system where the relay device determines which of the units act as primary and which a secondary. The disclosed switch is capable of reconfiguring the sequencing with a mere flip of a switch or a toggle of an actuator. There is a protective case enclosing the actual switch. The casing carries the dual role of insulating the switch and electrical connectors, as well as providing instructions on how to integrate the disclosed device into an existing heat pump system, as well as how to operate the device after successful integration. The wiring to the switch is accomplished via a panel of clearing marked external connectors. The switch can then operate via a mechanical or electronic actuator exposed on the surface of the protective case, or remotely via a connection module.

The disclosed invention is a relay switch that is capable of controlling the sequence in which a multi-unit heat pump system where the relay device determines which of the units act as primary and which a secondary. The disclosed switch is capable of reconfiguring the sequencing with a mere flip of a switch or a toggle of an actuator. There is a protective case enclosing the actual switch. The casing carries the dual role of insulating the switch and electrical connectors, as well as providing instructions on how to integrate the disclosed device into an existing heat pump system, as well as how to operate the device after successful integration. The wiring to the switch is accomplished via a panel of clearing marked external connectors. The switch can then operate via a mechanical or electronic actuator exposed on the surface of the protective case, or remotely via a connection module.

An air-cooled progressively two-stage refrigeration system comprising: a compressor; a condenser; and an evaporator, which is connected to the condenser and the compressor respectively, and the evaporator contains a high-temperature portion, a fan, and a middle-temperature portion, the high-temperature portion and the middle-temperature portion are respectively located on two sides of the evaporator, and the fan is set between the high-temperature portion and the middle-temperature portion, and air enters the evaporator from one side of the high-temperature portion, passes through the fan and then is sent out from one side of the middle-temperature portion, and a first evaporation coil is provided in the high-temperature portion, and a second evaporation coil is provided in the middle-temperature portion; wherein the fan accelerates the cooled air in the high-temperature portion to the middle-temperature portion to undergo another cooling process, so as to reduce the energy consumption of the system.