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.

Cooling systems and methods of operation are provided. The cooling system may comprise a two-phase pumped loop (TPPL). The two-phase pumped loop may include, a receiver, a pump downstream from the receiver, a heat load downstream from the pump, a TPPL tee downstream from the heat load, a TPPL check valve downstream from the TPPL tee, and a heat exchanger downstream from the TPPL check valve and upstream from the receiver. The cooling system may further include a vapor cycle system (VCS) loop. The vapor cycle system loop may include the receiver, a compressor downstream from a vapor outlet of the receiver, a compressor check valve downstream from the compressor and upstream of the heat exchanger, the heat exchanger, and the heat load downstream from a liquid outlet of the receiver.

Cooling systems and methods of operation are provided. The cooling system may comprise a two-phase pumped loop (TPPL). The two-phase pumped loop may include, a receiver, a pump downstream from the receiver, a heat load downstream from the pump, a TPPL tee downstream from the heat load, a TPPL check valve downstream from the TPPL tee, and a heat exchanger downstream from the TPPL check valve and upstream from the receiver. The cooling system may further include a vapor cycle system (VCS) loop. The vapor cycle system loop may include the receiver, a compressor downstream from a vapor outlet of the receiver, a compressor check valve downstream from the compressor and upstream of the heat exchanger, the heat exchanger, and the heat load downstream from a liquid outlet of the receiver.

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.

Provided are a fluid circulation system and a method for operating same, a computer-readable medium, and a controller. The fluid circulation system comprises: a scroll expander, and an external fluid circulation path, which comprises a high-pressure fluid pipe and a low-pressure fluid pipe. The operation method comprises the following steps: before fluid is supplied to the scroll expander, making the fluid pressure in the high-pressure fluid pipe higher than the fluid pressure in the low-pressure fluid pipe by a pre-determined pressure difference; and after the pre-determined pressure difference is realized, starting the scroll expander and supplying fluid to the scroll expander. According to the present disclosure, the technical problem of a scroll expander being unable to be normally started and work can be avoided, and the invention is simple, practical, convenient, and easily implemented.

Described is a regulation apparatus for a refrigeration plant having defined therein a refrigerant fluid path and a plurality of devices arranged along the refrigerant fluid path. The regulation apparatus includes a first sensor arranged in a first point (P1) and a second sensor arranged in a second point (P3), each along the fluid path of the refrigeration plant, a control unit and an actuation device. The control unit controls a first value measured by the first sensor and obtains a first regulation request deriving from the first measured value as well as a second value measured by the second sensor and derives a second regulation request deriving from the second measured value, compares the first and second regulation requests, and establishes which regulation request is greater. The control unit also commands the actuation device to actuate the most effective regulation request of the refrigeration plant devices.

Described is a regulation apparatus for a refrigeration plant having defined therein a refrigerant fluid path and a plurality of devices arranged along the refrigerant fluid path. The regulation apparatus includes a first sensor arranged in a first point (P1) and a second sensor arranged in a second point (P3), each along the fluid path of the refrigeration plant, a control unit and an actuation device. The control unit controls a first value measured by the first sensor and obtains a first regulation request deriving from the first measured value as well as a second value measured by the second sensor and derives a second regulation request deriving from the second measured value, compares the first and second regulation requests, and establishes which regulation request is greater. The control unit also commands the actuation device to actuate the most effective regulation request of the refrigeration plant devices.

A refrigeration system includes a dedicated defrost-mode compressor that delivers high pressure, high temperature refrigerant to one or more evaporators to defrost the evaporators.

A refrigeration system includes a dedicated defrost-mode compressor that delivers high pressure, high temperature refrigerant to one or more evaporators to defrost the evaporators.

A refrigeration system includes an expansion valve downstream of one or more medium temperature compressors. The expansion valve is configured to decrease pressure of a portion of refrigerant output by the one or more medium temperature compressors. When defrost operation of an evaporator is indicated, the refrigerant with decreased pressure from the expansion valve is provided to the evaporator for at least a period of time sufficient to defrost the evaporator.