A heat pump system and a control method therefor are provided. The heat pump system includes an outdoor heat exchanger and an electromagnetic heating assembly. The electromagnetic heating assembly includes an induction heating sheet, an insulation plate, and an electromagnetic induction wire coil. The induction heating sheet is in contact with the outdoor heat exchanger, the electromagnetic induction wire coil is attached to the insulation plate, the insulation plate is connected to the outdoor heat exchanger or the induction heating sheet, the induction heating sheet is coupled with the electromagnetic induction wire coil by communication.

A solar power refrigerant heating device for use in an air conditioning system includes an intake passageway and a plurality of intake valves are in fluid communication with the intake passageway. A plurality of heating chambers are in fluid communication with respective ones of the plurality of intake valves. A plurality of discharge valves are in communication with respective ones of the plurality of heating chambers. A solar powered temperature control device is in thermal communication with the heating chambers for converting solar energy into heat and selectively applying the heat to the heating chambers. The intake valves, the discharge valves, and the solar powered temperature control device are operatively connected to facilitate sequential receipt of refrigerant from the intake passageway into the heating chambers, heating of the received refrigerant within the heating chambers, and discharge of the refrigerant from the heating chambers according to a prescribed operational sequence.

A refrigerating and air-conditioning apparatus that performs defrosting operation, the refrigerating and air-conditioning apparatus including: a refrigerant circuit in which a compressor, a first heat exchanger, an expansion device, a second heat exchanger, and a four-way valve are connected to each other by pipes to allow refrigerant to circulate through the refrigerant circuit; a temperature sensor configured to measure a temperature of the compressor; and a heat generation control unit configured to increase a temperature of the compressor when the heat generation control unit detects a decrease in a value measured by the temperature sensor in defrosting operation performed on the first heat exchanger.

A refrigeration apparatus includes: a refrigerant circuit through which refrigerant circulates; a controller to execute a plurality of refrigerant shortage sensing functions of sensing a shortage of an amount of the refrigerant; and an input device through which an operation mode to be set is input into the controller. The operation mode includes: a first mode in which energy-saving performance is emphasized; and a second mode in which the refrigeration apparatus is permitted to operate in a range in which reliability is ensured. In accordance with the operation mode set through the input device, the controller determines which one of sensing results obtained by the refrigerant shortage sensing functions is enabled and which one of sensing results obtained by the refrigerant shortage sensing functions is disabled. When a sensing result determined to be enabled shows a refrigerant shortage, the controller gives a notification about the refrigerant shortage.

A system for a heat pump that allows the heat pump to work efficiently in extreme cold weathers. The system includes an evaporator in fluid communication with an expansion valve, the expansion valve can receive a liquid refrigerant from a condenser of the heat pump. The evaporator contains a pool of liquid refrigerant and an electric resistance heating source dipped in the pool of liquid refrigerant. The electric resistance heating source can heat the liquid refrigerant of the pool to generate vapors and thus maintaining a desired pressure within the heat pump.

A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

A method for conditioning a fluid in a temperature-insulated test space and a test space of a test chamber for receiving test materials. A cascading cooling device creates a particular temperature range within the test space, and the cooling device has a first cooling circuit comprising a cascading heat exchanger, a first compressor, a condenser and a first expanding element, and a second cooling circuit comprising a heat exchanger, a second compressor, the cascading heat exchanger and a second expanding element. The cascading heat exchanger is cooled by the first cooling circuit, the heat exchanger is cooled by a bypass passing through the heat exchanger and bridging the cascading heat exchanger, the first compressor is turned off, and a first refrigerant is conducted and condensed in a gaseous state in the cascading heat exchanger on a low-pressure side of the bypass.

A system for measuring oil circulation ratio in a vapor-compression refrigeration system (VCRS) is provided. The system may include an oil separator configured to receive the refrigerant and oil flow from the low-pressure line of the VCRS and output a oil flow and a refrigerant flow. The system may further include an oil collector configured to receive the separated oil flow provided by the oil separator. A valve may control an oil flow from the oil collector to the low-pressure line. A level sensor may measure oil level in the oil collector. The system may close, in response to the oil being at or less than a first level, the valve to collect oil in the oil collector. The system may open, in response to the oil being at or greater than a second level, the valve to release oil from the oil collector to the low-pressure line.

A method of operating a refrigeration system. The method includes operating a multi-temperature refrigeration system that has a plurality of heat absorption heat exchangers in a single temperature mode. A number of the plurality of heat absorption heat exchangers are determined that require defrosting a single heat absorption heat exchanger is directed into a different operational state when the number of heat absorption heat exchangers that require defrosting is equal to one. E of the plurality of heat absorption heat exchangers is directed into a defrost mode when the number of heat absorption heat exchangers that requires defrosting is more than one.

A heat exchanger within an insulated enclosure receives primary refrigerant at a high pressure and cools the primary refrigerant using a secondary refrigerant from a secondary refrigeration system. An expansion unit within the insulated enclosure receives the primary refrigerant at the high pressure from the heat exchanger and discharges the primary refrigerant at a low pressure. A supply line delivers the primary refrigerant at the low pressure to the load and a return line returns the primary refrigerant from the load to the primary refrigeration system. A system control unit controls operation of at least one of the primary refrigeration system and the secondary refrigeration system to provide a variable refrigeration capacity to the load based on at least one of: a pressure of the primary refrigerant delivered to the load, and at least one temperature of the load.