Disclosed is a refrigeration unit having an accumulator, a refrigeration system and a method for controlling a refrigeration unit having an accumulator, wherein the refrigeration unit has a refrigeration chamber for receiving and storing goods to be refrigerated, an accumulator having an accumulator holder in which a storage medium is accommodated, a heat exchanger, a controller and a coolant line arrangement which can be connected to a coolant supply network via connections. The coolant line arrangement is guided through the accumulator holder, and the heat exchanger is thermally coupled to the storage medium accommodated in the accumulator holder. A coolant control device is arranged in the flow pipe of the coolant arrangement, wherein the storage medium accommodated in the accumulator holder is cooled via a coolant in the coolant line arrangement, and the heat exchanger is cooled via the storage medium.

A refrigeration system for a temperature-controlled storage device includes a refrigeration circuit, a cooling circuit, and a controller. The refrigeration circuit includes a compressor driven by a brushless DC motor operable at multiple different speeds, a first heat exchanger, an expansion device, and a cooling unit in fluid communication via a first working fluid. The cooling circuit includes a pump and a second heat exchanger in fluid communication with the first heat exchanger via a second working fluid such that the first heat exchanger is liquid-cooled by the second working fluid. The controller operates the brushless DC motor at multiple different speeds to accommodate multiple different thermal loads experienced by the refrigeration system. Each of the speeds corresponds to a different thermal load. The controller modulates the speed of the brushless DC motor to maintain a desired temperature of a temperature-controlled space within the temperature-controlled device.

The present invention provides a refrigerant composition comprising: (a) from about 65% by weight to about 90% by weight of HFO-1234ze (E); (b) from about 10% by weight to about 35% by weight of HFO-1336mzz (E); and optionally (c) from about 0% to about 4.4% by weight of HFC-227ea for use in a variety of refrigeration applications, including air conditioning and/or refrigeration and particularly cooling products such as fruits, vegetables and beverages without exposing those articles to temperatures below the freezing point of water.

A refrigeration plant with a cooling circuit, comprising at least one peripheral unit having a refrigeration machine for refrigerating a storage compartment; the refrigeration machine having a heat exchanger connected to the cooling circuit for dissipating heat to a secondary fluid flowing therein; a cooling apparatus connected to the cooling circuit for cooling the secondary fluid; a control device connected to the cooling apparatus and configured to operate the cooling apparatus so as to maintain at least an operating temperature of the secondary fluid within at least a corresponding reference range or to equalize it to at least a corresponding target value.

A refrigeration system includes an evaporator within which a refrigerant absorbs heat, a gas cooler/condenser within which the refrigerant rejects heat, a compressor operable to circulate the refrigerant between the evaporator and the gas cooler/condenser, a high pressure valve operable to control a pressure of the refrigerant at an outlet of the gas cooler/condenser, and a controller. The controller is configured to automatically generate a setpoint for a measured or calculated variable of the refrigeration system based on a measured temperature of the refrigerant at the outlet of the gas cooler/condenser. The setpoint is generated using a stored relationship between the measured temperature and a maximum estimated coefficient of performance (COP) that can be achieved at the measured temperature. The controller is configured to operate the high pressure valve to drive the measured or calculated variable toward the setpoint.

The present invention provides a refrigerant composition comprising: (a) from about 65% by weight to about 90% by weight of HFO-1234ze(E); (b) from about 10% by weight to about 35% by weight of HFO-1336mzz (E); and optionally (c) from about 0% to about 4.4% by weight of HFC-227ea for use in a variety of refrigeration applications, including air conditioning and/or refrigeration and particularly cooling products such as fruits, vegetables and beverages without exposing those articles to temperatures below the freezing point of water.

Systems and methods for controlling pressure in a CO.sub.2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO.sub.2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO.sub.2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO.sub.2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

A refrigeration system for a temperature-controlled storage device includes a refrigeration circuit that circulates a refrigerant, a separate cooling circuit that circulates a coolant, and a controller. The refrigeration circuit includes a compressor, a condenser, an expansion device, and an evaporator. The cooling circuit includes a pump, a control valve, and a heat removing device in fluid communication with the condenser via the coolant. The controller is operatively coupled to the control valve and configured to identify a coolant temperature differential setpoint, monitor a temperature of the coolant provided to the condenser by the cooling circuit, calculate a coolant temperature differential based on the temperature of the coolant provided to the condenser, and operate the control valve to modulate a flow of the coolant through the condenser to drive the coolant temperature differential to the coolant temperature differential setpoint.

A freezer case includes a refrigeration system and a controller. The controller is configured to store a plurality of setpoint instruction sets associated with a plurality of possible operating modes, select a current operating mode from the plurality of possible operating modes, assign a value for the superheat setpoint by executing the setpoint instruction set associated with the current operating mode, control the refrigeration system in accordance with the superheat setpoint.

A refrigerated display case having a housing defining a temperature controlled space and a refrigeration system coupled to the housing is provided. The refrigeration system is configured to be operable to affect a temperature of the temperature controlled space. The refrigeration system includes an actuator, a controller, and a sensor. The controller is configured to continuously update a stored position of the actuator based on measurement of an electric current provided to the actuator, retrieve the stored position after a power failure, and restart control based on the stored position of the actuator. The sensor is configured to communicate with the controller.