Abstract: A method for operating a refrigeration system in order to perform temperature control of a closed volume is disclosed. The refrigeration system comprising a compressor, a condenser, an expansion device and an evaporator connected in series in a refrigerant flow path. The refrigeration system further comprises one or more fans arranged to cause a flow of air across the evaporator. The compressor is controlled by switching the compressor on or off in accordance with a measured temperature, Tsup, of air which has passed across the evaporator and is being supplied to the closed volume, and in order to achieve a set point temperature, Tset, in the closed volume. During this a compressor switching pattern is determined. Temperature fluctuations inside the closed volume are minimized, and energy is conserved.

Abstract: Temperature is controlled in a refrigerated transport container comprising a transport volume, a control unit, a cooling space, one or more fans providing air flow through the cooling space, where air passing through the cooling space passes a return air temperature sensor, a cooling unit, and a supply air temperature sensor. Supply air temperature (Tsup) is controlled to bring temperatures in the transport volume within a desired temperature range around a first temperature set point (Tset). The supply air temperature (Tsup) or a time-averaged function thereof is controlled to reach a temperature below the set point (Tset) during a first limited time period; and the supply air temperature (Tsup) is increased during a second limited time period following said first time period, so that the supply air temperature (Tsup) or a time-averaged function thereof at the end of said second time period is within said desired temperature range.

Abstract: A valve (4) for a refrigeration system. Comprises two diaphragms (8, 10) being operatively connected. One diaphragm (8) is in contact with the refrigerant, the other (10) is in contact with the filling fluid. The two diaphragms (8, 10) may have different active areas. In combination with the connection between the two diaphragms (8, 10) this provides a ‘pressure gearing’ between the filling fluid and the refrigerant. Allows the pressure of the filling fluid to be relatively low even when the pressure of the refrigerant is high, while ensuring that the valve (4) can function properly. Particularly suitable for high pressure refrigeration systems, such as CO2 systems.

Abstract: Temperature is controlled in a refrigerated transport container comprising a transport volume, a control unit, a cooling space, one or more fans providing air flow through the cooling space, where air passing through the cooling space passes a return air temperature sensor, a cooling unit, and a supply air temperature sensor. Supply air temperature (Tsup) is controlled to bring temperatures in the transport volume within a desired temperature range around a first temperature set point (Tset). The supply air temperature (Tsup) or a time-averaged function thereof is controlled to reach a temperature below the set point (Tset) during a first limited time period; and the supply air temperature (Tsup) is increased during a second limited time period following said first time period, so that the supply air temperature (Tsup) or a time-averaged function thereof at the end of said second time period is within said desired temperature range.

Abstract: A valve (4) for a refrigeration system. Comprises two diaphragms (8, 10) being operatively connected. One diaphragm (8) is in contact with the refrigerant, the other (10) is in contact with the filling fluid. The two diaphragms (8, 10) may have different active areas. In combination with the connection between the two diaphragms (8, 10) this provides a ‘pressure gearing’ between the filling fluid and the refrigerant. Allows the pressure of the filling fluid to be relatively low even when the pressure of the refrigerant is high, while ensuring that the valve (4) can function properly. Particularly suitable for high pressure refrigeration systems, such as CO2 systems.

Abstract: A method for regulating a most loaded circuit of a refrigeration system is provided. Each circuit includes at least one case and an EEPR valve. At least one controller communicates with the EEPR valves for receiving signals from the circuits corresponding to operating conditions for each circuit, and for issuing command signals to the EEPR valves and compressor. The operation of each circuit is monitored and a load signal is calculated for each circuit. The load signals for each circuit are compared and the most loaded circuit is determined. The EEPR valve of the most loaded circuit is adjusted to be approximately 100 percent open and a suction pressure of the compressor is adjusted to move a circuit temperature of the most loaded circuit to a target temperature. The process of selecting and regulating the most loaded circuit is repeated after a predetermined period of time.

Abstract: A controller for an expansion valve of a refrigeration system for cooling a medium is configured to include, in the generation of a control signal, a measure of the evaporation temperature (T0) of the refrigerant in an evaporator and a measure of a property of the cooled medium, preferably without influence from a measure of the superheat temperature (SH) of the refrigerant. The controller comprises a PI-element for integrating and for producing a control signal for the expansion valve for controlling the flow of refrigerant into the evaporator, the PI-element being arranged in an inner control loop, a reference for which is produced by an outer control loop. The controller allows for fast response to disturbances and/or fast response of the medium temperature when the operating conditions of the refrigeration system are changed and/or fast response during start-up of the refrigeration system and maintains stable operation conditions with low, but positive superheating and a stable evaporation pressure.

Abstract: A controller for an expansion valve of a refrigeration system for cooling a medium is configured to include, in the generation of a control signal, a measure of the evaporation temperature (T0) of the refrigerant in an evaporator and a measure of a property of the cooled medium, preferably without influence from a measure of the superheat temperature (SH) of the refrigerant. The controller comprises a PI-element for integrating and for producing a control signal for the expansion valve for controlling the flow of refrigerant into the evaporator, the PI-element being arranged in an inner control loop, a reference for which is produced by an outer control loop. The controller allows for fast response to disturbances and/or fast response of the medium temperature when the operating conditions of the refrigeration system are changed and/or fast response during start-up of the refrigeration system and maintains stable operation conditions with low, but positive superheating and a stable evaporation pressure.