A refrigerator includes a compressor configured to compress a refrigerant, a condenser configured to condense the refrigerant compressed in the compressor, an expander configured to depressurize the refrigerant condensed in the condenser, a plurality of evaporators configured to evaporate the refrigerant depressurized in the expander, a first valve configured to be operated to introduce the refrigerant into at least one of the plurality of evaporators, a hot gas valve device disposed at an inlet side of the first valve and configured to guide the refrigerant passed through the compressor or the condenser to the plurality of evaporators, and a hot gas path configured to extend from the hot gas valve device to the plurality of evaporators.

There is provided a HVAC system comprising: a fluid circuit for conveying a refrigerant; a compressor for compressing the refrigerant; three heat exchangers defining an evaporator, an outdoor exchanger and a heat recovery exchanger provided along the fluid circuit; an expansion valve provided along the fluid circuit; and a receiver connected in parallel to the expansion valve, wherein a fill valve is located between the receiver and a connection upstream of the expansion valve and a drain valve is located between the receiver and a connection downstream of the expansion valve; wherein the fluid circuit comprises a plurality of valves which are configured to be controlled based on a selected operating mode such that at least one of the outdoor exchanger and the heat recovery exchanger is connected to a discharge line of the compressor and in series with one of the other heat exchangers which is connected to a suction line of the compressor, with the expansion valve disposed between the heat exchangers; wherein the fill and drain valves are configured to be controlled to store a volume of refrigerant in the receiver so as to provide an effective refrigerant charge in the fluid circuit that corresponds to the selected operating mode.

Systems and methods have demonstrated the capability of rapidly cooling the contents of pods containing the ingredients for food and drinks.

A heat pump system and a control method thereof. The heat pump system includes: a compressor; an indoor heat exchanger; an outdoor heat exchanger configured as an interlaced heat exchanger having at least two refrigerant flow paths; a plurality of throttling elements; and a first type four-way valve and a second type four-way valve; in a local defrosting mode, refrigerant flows sequentially from the exhaust port of the compressor through at least one of the at least two refrigerant flow paths of the outdoor heat exchanger, the throttling element, at least another of the at least two refrigerant flow paths of the outdoor heat exchanger and the suction port of the compressor.

A heat pump system includes a compressor; an indoor heat exchanger; an outdoor heat exchanger configured as an interlaced heat exchanger having at least two refrigerant flow paths; a plurality of throttling elements; and a first type four-way valve and a second type four-way valve, with ports thereof respectively connected to the inlet and the outlet of the compressor, the indoor heat exchanger, and one of the at least two refrigerant flow paths of the outdoor heat exchanger; in a local defrosting mode, refrigerant from the outlet of the compressor flows respectively through the indoor heat exchanger and at least one of the at least two refrigerant flow paths of the outdoor heat exchanger, and then sequentially through the throttling elements, at least the other of the at least two refrigerant flow paths of the outdoor heat exchanger, and the inlet of the compressor.

A method for terminating defrosting of an evaporator (104) is disclosed. The evaporator (104) is part of a vapour compression system (100). The vapour compression system (100) further comprises a compressor unit (101), a heat rejecting heat exchanger (102), and an expansion device (103). The compressor unit (101), the heat rejecting heat exchanger (102), the expansion device (103) and the evaporator (104) are arranged in a refrigerant path, and an air flow is flowing across the evaporator (104). When ice is accumulated on the evaporator (104), the vapour compression system (100) operates in a defrosting mode. At least one temperature sensor (305) monitors a temperature T.sub.air, of air leaving the evaporator (104). A rate of change of T.sub.air is monitored and defrosting is terminated when the rate of change of the temperature, T.sub.air, approaches zero.

A continuous heating control system and method, and an air-conditioning device. The system includes a defrosting solenoid valve (1) arranged on a bypass pipeline, wherein one end of the bypass pipeline is connected to an oil separator (2), and the other end of the bypass pipeline is connected to an outdoor heat exchanger (3); and a heating structure which is arranged at the bottom of a gas separator (4) and used for heating the gas separator (4).

Disclosed are a carbon dioxide overlapping type heating system and a control method therefor. The heating system comprises a low-temperature stage loop, a high-temperature stage loop and a heat supply loop, wherein a low-temperature stage compressor (3) and a high-temperature stage compressor (7) are both variable-frequency compressors; and a water pump (10) is a variable-frequency water pump.

A heat pump system with a refrigerant flow path comprising, in the heating mode of operation: a compressor coupled to receive refrigerant from a heating mode first refrigerant stream and a heating mode second refrigerant stream of the refrigerant flow path; the condenser coupled to receive refrigerant from the compressor; and a heat exchanger for transferring heat between the heating mode first refrigerant stream and the heating mode second refrigerant stream, wherein the heating mode first refrigerant stream comprises: the first expansion valve coupled to receive refrigerant from the condenser; the first evaporator coupled to receive refrigerant from the first expansion valve; and the heat exchanger coupling the heating mode first refrigerant stream from the first evaporator to the compressor, wherein the heating mode second refrigerant stream comprises: the second expansion valve; the heat exchanger coupling the heating mode second refrigerant stream from the condenser to the second expansion valve; and the second evaporator being coupled to communicate refrigerant from the second expansion valve to the compressor, wherein the first evaporator is in a first air flow conduit with a first air inlet for receiving a first air flow, and the second evaporator is in a second air flow conduit coupled to receive the first air flow.

A heating, ventilation, and/or air conditioning (HVAC) system includes a compressor having an impeller configured to rotate and drive a working fluid through a working fluid circuit of the HVAC system in an active operating mode. The HVAC system further includes a controller configured to, in response to receiving an input indicative of a transition to operate in an inactive operating mode, suspend the active operating mode by interrupting a supply of power to the compressor, adjust pre-rotation vanes of the compressor, a variable geometry diffuser of the compressor to a first position, or both to enable a backflow of the working fluid through the compressor for a first interval of time, and, after the first interval of time has elapsed, adjust the pre-rotation vanes, the variable geometry diffuser, or both to a second position to block the backflow of the working fluid through the compressor.