A hot gas bypass circuit that connects a discharge side of the compressor and a portion between the heat source side heat exchanger and the expansion valve, an on-off valve that opens and closes a channel of the hot gas bypass circuit, and a control device performing control to select one of hot gas bypass defrosting and reverse cycle defrosting according to a frosting amount on the heat source side heat exchanger and perform defrosting. The control device controls to open the on-off valve of the hot gas bypass circuit such that a part of a refrigerant discharged from the compressor is supplied to the heat source side heat exchanger via the hot gas bypass circuit and, the control device switches switch the four-way valve such that the refrigerant discharged from the compressor is supplied to the heat source side heat exchanger after passing through the four-way valve.

Provided is a refrigeration apparatus in which a decrease in a temperature of an indoor heat exchanger can be suppressed as much as possible while depletion of refrigerator oil in a compressor is also suppressed. An air-conditioning apparatus configured from a parallel connection of a plurality of outdoor units to an indoor unit, wherein when a predetermined defrosting condition has been fulfilled, a controller includes at least one processor programmed to selectively execute a reverse-cycle defrost mode when a predetermined outflow condition pertaining to an outflow integrated quantity of refrigerator oil has also been fulfilled, and selectively execute an alternating defrost mode, in which the outdoor unit that is to be defrosted is changed in sequence, when the predetermined outflow condition has not been fulfilled.

A refrigerator, provided with: a storage compartment, at least divided into a refrigerating compartment (3) and a freezing compartment (4); a first evaporator (22), provided in a cooling chamber (8) connected to the storage compartment (3, 4) by means of a supply duct (9, 10); a second evaporator (23) provided inside of the freezing compartment (4); a switch valve (25), used for switching a refrigerant to flow or not flow to a refrigerant passage connected to the second evaporator (23); a fan (13), used for flowing air cooled by the first evaporator (22) from the cooling chamber (8) to the storage compartment (3, 4); a first duct shutter (11), inserted in the supply duct (9) connected to the refrigerating compartment (3); and a second duct shutter (12), inserted in the supply duct (9) connected to the freezing compartment (4). The refrigerator may prevent the storage compartment (3, 4) from becoming dry, thereby reducing defrost instances and power consumption.

A cold storage includes a compartment, a first evaporator chamber in fluid communication with the compartment, a second evaporator chamber in fluid communication with the compartment, a first cooling system and a second cooling system, each cooling system comprising a compressor unit, a condenser structure, a first evaporator, a second evaporator, and a controller configured to control flow of refrigerant from the condenser structure to one or both of the first and second evaporators. To allow full operation with one of the two cooling systems and thereby preserve the other cooling system as a spare system, the first evaporators are arranged in the first evaporator chamber, and the second evaporators are arranged in the second evaporator chamber, allowing both chambers to be operated with each of the two cooling systems.

A refrigerating and air-conditioning system includes a plurality of independent refrigerating and air-conditioning apparatuses each including a refrigerant circuit and a defrosting unit, and further includes a system controller managing the apparatuses in an integrative manner. The system controller includes a defrosting operation control unit. When a time interval between an estimated defrosting start time calculated for a given refrigerating and air-conditioning apparatus and a subsequent estimated defrosting start time calculated for another refrigerating and air-conditioning apparatus is less than or equal to a predetermined target start time interval, the defrosting operation control unit transmits a defrosting start instruction signal to the defrosting unit of the given refrigerating and air-conditioning apparatus.

A refrigeration system includes a controllable valve positioned downstream from one or more low-temperature compressors. The controllable valve receives compressed refrigerant from the low-temperature compressors and directs flow of the refrigerant to one or both of (i) medium-temperature compressors downstream from the controllable valve and (ii) one or more evaporators based on an operation mode of the evaporators. A pressure-regulating valve is disposed in refrigerant conduit coupling a first flash tank to a second flash tank. After determining to operate a first evaporator in a defrost mode, a controller adjusts the controllable valve to direct a portion of refrigerant to the first evaporator and adjusts the pressure-regulating valve to increase a pressure of the first flash tank relative to that of the second flash tank.

A refrigeration cycle apparatus including a refrigerant circuit including a compressor, an indoor heat exchanger, an expansion device, an outdoor heat exchanger, an outside air temperature sensor, and a controller configured to perform a hot gas defrosting operation and a reverse-defrosting operation based on a temperature obtained by the outside air temperature sensor. In the hot gas defrosting operation, hot gas discharged from the compressor without passing through the indoor heat exchanger is supplied to the outdoor heat exchanger. In the reverse-defrosting operation, refrigerant passing through the indoor heat exchanger is supplied from the compressor to the outdoor heat exchanger. The controller has at least a mixed defrosting operation mode in which the hot gas defrosting operation and the reverse-defrosting operation are performed in sequence. The controller is configured to start the mixed defrosting operation mode when the temperature obtained by the outside air temperature sensor satisfies a preset condition.

A refrigeration cycle apparatus includes a refrigerant circuit including a compressor, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger connected to each other via refrigerant pipes. The outdoor heat exchanger includes a heat transfer pipe, and a plurality of fins. The outdoor heat exchanger is configured so that a ratio of a heat capacity of the plurality of fins to a total of heat capacities of the heat transfer pipe and the plurality of fins is not more than 50%. The refrigeration cycle apparatus has a mixed defrosting operation mode in which a hot gas defrosting operation and a reverse-defrosting operation are performed in sequence. In the hot gas defrosting operation, hot gas discharged from the compressor is supplied to the outdoor heat exchanger. In the reverse-defrosting operation, refrigerant passing through the indoor heat exchanger is supplied from the compressor to the outdoor heat exchanger.

A refrigerator and method utilize a pair of tandem evaporators to provide cooling for both a compartment and an ice making system of a refrigerator. An upstream evaporator in the pair of tandem evaporators provides cooling for a compartment such as a freezer, fresh food, flexible cooling, or quick cooling compartment, while a downstream evaporator is in fluid communication with the upstream evaporator to receive a portion of the air cooled by the upstream evaporator and further cool the received portion for use in cooling one or more components of the ice making system.

An air-to-water heat pump system is disclosed comprising a lower heat source unit and an upper heat source unit connected in a thermodynamic cycle, wherein the lower heat source unit is supplied with external air and the lower heat source has at least two alternating evaporators (1, 2) forming the lower heat source with a fan mounted axially in relation to the lower heat source unit in its upper part, provided with a defrosting unit in which it is possible to implement the defrosting and drying process of the evaporator heat exchange surface, as well as improve the energy efficiency of the heat pump system.