Abstract: A transcritical R-744 refrigeration system with a medium temperature section having a plurality of circuits, at least one evaporator receiving an R-744 refrigerant in a medium-pressure liquid state from a receiver and feeding at least one transcritical compressor to compress the R-744 refrigerant from a low-pressure gaseous state into a high-pressure gaseous state to feed a gas cooler and a throttling device to partially condense the R-744 refrigerant into a medium-pressure gaseous-liquid state, the system comprising a pressure reducing valve connected to a discharge conduit of the at least one transcritical compressor and feeding hot gas to a defrost manifold to defrost one of the plurality of circuits of the medium temperature section, wherein the hot gas being fed to the defrost manifold has a pressure value less than or equal to a maximum operating pressure of the at least one evaporator.

Abstract: A transcritical R-744 refrigeration system comprising at least one first compressor for compressing an R-744 refrigerant, a gas cooler for cooling the R-744 refrigerant compressed by the at least one first compressor, a throttling device for decreasing the pressure of the cooled R-744 refrigerant, a receiver for separating the R-744 refrigerant, a first heat exchanger for exchanging heat between the cooled R-744 refrigerant and the R-744 vapors separated by the receiver before the R-744 vapors are transported to the at least one first compressor, and an integrated R-744 refrigerant-based air-conditioning assembly comprising a second plurality of compressors and an air conditioner comprising a second heat exchanger and an evaporator, wherein the system is operatable in a dehumidification mode wherein the R-744 vapors exiting the gas cooler are fed through the second heat exchanger to heat and dehumidify the passing ambient air before being fed to the receiver.

Abstract: A mechanical subcooling system operatively connectable to a transcritical R-744 refrigeration system resulting in an energy efficiency ratio of a level comparable to that of refrigeration systems using common refrigerants. Mechanical subcooling increases the refrigeration capacity without increasing the power consumption of the refrigeration system's compressors. The compressors used to provide the refrigeration capacity for the subcooling process operate at much more favorable conditions, thus having a very high energy efficiency ratio. The result is higher refrigeration capacity and lower power consumption.

Abstract: A transcritical R-744 refrigeration system comprising at least one first compressor for compressing an R-744 refrigerant, a gas cooler for cooling the R-744 refrigerant compressed by the at least one first compressor, a throttling device for decreasing the pressure of the cooled R-744 refrigerant, a receiver for separating the R-744 refrigerant, a first heat exchanger for exchanging heat between the cooled R-744 refrigerant and the R-744 vapors separated by the receiver before the R-744 vapors are transported to the at least one first compressor, and an integrated R-744 refrigerant-based air-conditioning assembly comprising a second plurality of compressors and an air conditioner comprising a second heat exchanger and an evaporator, wherein the system is operatable in a dehumidification mode wherein the R-744 vapors exiting the gas cooler are fed through the second heat exchanger to heat and dehumidify the passing ambient air before being fed to the receiver.

Abstract: A mechanical subcooling system operatively connectable to a transcritical R-744 refrigeration system resulting in an energy efficiency ratio of a level comparable to that of refrigeration systems using common refrigerants. Mechanical subcooling increases the refrigeration capacity without increasing the power consumption of the refrigeration system's compressors. The compressors used to provide the refrigeration capacity for the subcooling process operate at much more favorable conditions, thus having a very high energy efficiency ratio. The result is higher refrigeration capacity and lower power consumption.

Abstract: A transcritical R-744 refrigeration system with a medium temperature section having a plurality of circuits, at least one evaporator receiving an R-744 refrigerant in a medium-pressure liquid state from a receiver and feeding at least one transcritical compressor to compress the R-744 refrigerant from a low-pressure gaseous state into a high-pressure gaseous state to feed a gas cooler and a throttling device to partially condense the R-744 refrigerant into a medium-pressure gaseous-liquid state, the system comprising a pressure reducing valve connected to a discharge conduit of the at least one transcritical compressor and feeding hot gas to a defrost manifold to defrost one of the plurality of circuits of the medium temperature section, wherein the hot gas being fed to the defrost manifold has a pressure value less than or equal to a maximum operating pressure of the at least one evaporator.

Abstract: A mechanical subcooling system operatively connectable to a transcritical R-744 refrigeration system resulting in an energy efficiency ratio of a level comparable to that of refrigeration systems using common refrigerants. Mechanical subcooling increases the refrigeration capacity without increasing the power consumption of the refrigeration system's compressors. The compressors used to provide the refrigeration capacity for the subcooling process operate at much more favorable conditions, thus having a very high energy efficiency ratio. The result is higher refrigeration capacity and lower power consumption.

Abstract: A transcritical R-744 refrigeration system, especially used for refrigerating a skating rink, has a heat exchanger between the gas cooler followed by a throttling device and the flash tank (or receiver), in order to eliminate the need of a flash-gas bypass. The heat exchanger connects to an external mechanical refrigeration system operating at a higher evaporating temperature than the transcritical R-744 refrigeration system, and generally totally condenses the vapor of the R-744 refrigerant before it reaches the flask tank. A method for improving the energy efficiency of the transcritical R-744 refrigeration system is also disclosed.

Abstract: A transcritical R-744 refrigeration systems for supermarkets with dehumidifying capability where the heat of the R-744 leaving the gas cooler is used for dehumidifying. The same heat exchanger is used for heat reclaim and dehumidifying purposes.

Abstract: A transcritical R-744 refrigeration system with an energy efficiency ratio of a level comparable to that of refrigeration systems using common refrigerants by mechanically subcooling of the R-744 refrigerant. Mechanical subcooling increases the refrigeration capacity without increasing the power consumption of the refrigeration system's compressors. The compressors used to provide the refrigeration capacity for the subcooling process operate at much more favorable conditions, therefore have a very high energy efficiency ratio. The result is higher refrigeration capacity and lower power consumption.

Abstract: A transcritical R-744 refrigeration system, especially used for refrigerating a skating rink, has a heat exchanger between the gas cooler followed by a throttling device and the flash tank (or receiver), in order to eliminate the need of a flash-gas bypass. The heat exchanger connects to an external mechanical refrigeration system operating at a higher evaporating temperature than the transcritical R-744 refrigeration system, and generally totally condenses the vapor of the R-744 refrigerant before it reaches the flask tank. A method for improving the energy efficiency of the transcritical R-744 refrigeration system is also disclosed.

Abstract: A cascade refrigeration system using a first refrigerant or a high stage and a second, R-744, refrigerant for low stage refrigeration has a defrost system including a defrost compressor, a defrost inlet heat exchanger and defrost outlet heat exchanger. The defrost inlet heat exchanger receives a defrost portion of second refrigerant and adds an additional defrost heat load thereto from first refrigerant, thus evaporating defrost portion. Defrost portion is then compressed into high pressure defrost vapor portion in the defrost compressor. The defrost vapor portion is then circulated through a selected evaporator, where a defrost heat, augmented by additional defrost heat load, defrosts selected evaporator, defrost vapor being at least partially condensed into defrost condensed portion which is liquefied in defrost outlet heat exchanger.

Abstract: A transcritical R-744 refrigeration system with an energy efficiency ratio of a level comparable to that of refrigeration systems using common refrigerants by mechanically subcooling of the R-744 refrigerant. Mechanical subcooling increases the refrigeration capacity without increasing the power consumption of the refrigeration system's compressors. The compressors used to provide the refrigeration capacity for the subcooling process operate at much more favorable conditions, therefore have a very high energy efficiency ratio. The result is higher refrigeration capacity and lower power consumption.

Abstract: A suction compressor temperature regulator device, for use with at least one compressor of a R-744 refrigeration system, includes a heating mechanism located upstream of the at least one compressor of the refrigeration system, in a suction line thereof, for locally controlling the temperature of a R-744 fluid of the refrigeration system. The heating mechanism is typically in a form of a heat exchanger connected to the suction line and using a heating fluid to transfer heat therefrom to the R-744 fluid at the heat exchanger.

Abstract: A cascade refrigeration system using a first refrigerant or a high stage and a second, R-744, refrigerant for low stage refrigeration has a defrost system including a defrost compressor, a defrost inlet heat exchanger and defrost outlet heat exchanger. The defrost inlet heat exchanger receives a defrost portion of second refrigerant and adds an additional defrost heat load thereto from first refrigerant, thus evaporating defrost portion. Defrost portion is then compressed into high pressure defrost vapor potion in the defrost compressor. The defrost vapor portion is then circulated through a selected evaporator, where a defrost heat, augmented by additional defrost heat load, defrosts selected evaporator, defrost vapor being at least partially condensed into defrost condensed portion which is liquefied in defrost outlet heat exchanger.

Abstract: A dual refrigerant refrigerating system provides a refrigeration cycle in which a primary refrigerant cools a secondary refrigerant in a primary evaporator into a partially frozen state, in which a fusion portion thereof is frozen. The primary refrigerant thus absorbs a secondary latent heat from secondary refrigerant, including a latent heat of fusion required for freezing the fusion portion. Secondary refrigerant is subsequently at least partially thawed, in a secondary evaporator, by re-absorption thereby of secondary latent heat from material proximal to secondary evaporator. Evaporation in secondary evaporator requires at least partial thawing of fusion portion, and thus latent heat of fusion is at least partially re-absorbed by secondary refrigerant, thus increasing secondary heat absorbed from material and facilitating refrigeration thereof. The system also provides defrost and heat reclaim capabilities.

Abstract: A subcooling heat exchanger and subcooling expansion valve in a refrigeration system provide subcooling of a pre-subcooled portion, for refrigerating a thermal load, of condensed refrigerant liquid by a pre-subcooling portion of the condensed refrigerant liquid. The amount of subcooling of the pre-subcooled portion is determined by measuring, with a pressure sensor, refrigerating suction pressure exerted by refrigerating compressors of the system. A controller then controls, based on the refrigerating suction pressure, modulation of mass of pre-subcooling portion, relative pre-subcooled portion, and expansion thereof in the subcooling expansion valve, which controls the amount of refrigerant heat exchanged, and therefore subcooling of pre-subcooled portion, between the pre-subcooling portion and the pre-subcooled portion in the subcooling heat exchanger. The pre-subcooling portion is then subsequently compressed by a subcooling compressor.

Abstract: A heat reclaim refrigeration system uses a first compressor to elevate the amount of latent heat reclaimable by the system and to reclaim this heat using heat reclaim means, such as heat reclaim coils, for practical applications, such as heating a building. In addition, the system reduces pressure required from a second compressor used for refrigeration, and energy consumed thereby, especially during cold periods of the year when a refrigerant condensing means has lower condensing requirements.

Abstract: A dual refrigerant refrigerating system provides a refrigeration cycle in which a primary refrigerant cools a secondary refrigerant in a primary evaporator into a partially frozen state, in which a fusion portion thereof is frozen. The primary refrigerant thus absorbs a secondary latent heat from secondary refrigerant, including a latent heat of fusion required for freezing the fusion portion. Secondary refrigerant is subsequently at least partially thawed, in a secondary evaporator, by re-absorption thereby of secondary latent heat from material proximal to secondary evaporator. Evaporation in secondary evaporator requires at least partial thawing of fusion portion, and thus latent heat of fusion is at least partially re-absorbed by secondary refrigerant, thus increasing secondary heat absorbed from material and facilitating refrigeration thereof. The system also provides defrost and heat reclaim capabilities.

Abstract: A heat reclaim refrigeration system uses a first compressor to elevate the amount of latent heat reclaimable by the system and to reclaim this heat using heat reclaim means, such as heat reclaim coils, for practical applications, such as heating a building. In addition, the system reduces pressure required from a second compressor used for refrigeration, and energy consumed thereby, especially during cold periods of the year when a refrigerant condensing means has lower condensing requirements.