Patent application number | Description | Published |
20090217686 | SYSTEM AND METHOD FOR SECONDARY COOLANT PUMP CONTROL FOR A REFRIGERATION SYSTEM - A system and method is provided for controlling the operation of secondary coolant pump(s) in a refrigeration system having a secondary coolant system that circulates the coolant to applicable cooling loads, and a primary refrigeration system that chills the coolant in the secondary coolant system. The system and method for controlling the pumps measures the pressure of the plurality of secondary coolant fluid loops, sorts the measurements to identify a secondary coolant fluid loop with a pressure farthest from a setpoint, and adjusts pump speed to compensate for the critical loop (i.e., the secondary coolant fluid loop with a pressure furthest from the setpoint). | 09-03-2009 |
20090260381 | FREE COOLING CASCADE ARRANGEMENT FOR REFRIGERATION SYSTEM - A refrigeration system includes a medium temperature subsystem circulating a coolant in a closed loop between at least one medium temperature chiller and at least one medium temperature load and at least one cascade heat exchanger, and a low temperature subsystem circulating a coolant in a closed loop between at least one low temperature chiller and at least one low temperature load. A cooling circuit is provided for circulating a coolant and includes a first pump and a second pump and a fluid cooler and a valve, and interfaces with the medium temperature chiller and the low temperature chiller. The valve is movable to a closed position to define a first flow path and a second flow path, where the first flow path includes the first pump and the medium temperature chiller and fluid cooler, and the second flow path including the second pump and the low temperature chiller and the cascade heat exchanger. | 10-22-2009 |
20090293517 | REFRIGERATION SYSTEM WITH A CHARGING LOOP - A refrigeration system includes a primary loop that cools a secondary loop that circulates a coolant through a refrigeration load. The secondary loop includes a suction header to receive the coolant from the load, and a discharge header to direct the coolant to the heat exchanger, and a pump to pump the coolant from the suction to the discharge header. A charging loop maintains a pressure of the coolant in the supply header within a predetermined range, and includes an inlet from the discharge header and an outlet to the suction header. A flow nozzle and a valve are located between the inlet and the outlet, and a reservoir of make-up coolant communicates with the flow nozzle. Upon a low pressure condition in the suction header, the valve opens to permit flow of coolant through the flow nozzle to draw in make-up coolant from the reservoir. | 12-03-2009 |
20090293523 | SYSTEM AND METHOD FOR USING A PHOTOVOLTAIC POWER SOURCE WITH A SECONDARY COOLANT REFRIGERATION SYSTEM - A secondary coolant refrigeration system powered primarily by a photovoltaic source and by an alternating current (AC) source as a backup is disclosed. The secondary coolant refrigeration system has a pump for pumping secondary coolant fluid through a secondary coolant fluid loop. The system includes a variable frequency drive for controlling the speed of the pump. The variable frequency drive includes drive circuitry configured to provide variable frequency power to the pump via an output interface. The variable frequency drive also includes a first interface configured to receive power from the photovoltaic source and a second interface configured to receive power from the AC source. The variable frequency drive further includes a circuit configured to switch between providing power to the drive circuitry from the first interface and providing power to the drive circuitry from the second interface. The circuit is further configured to cause the variable speed drive to be powered by the photovoltaic source when the power received from the first interface is adequate and by the AC source when the power received from the first interface is not adequate. | 12-03-2009 |
20100023171 | REFRIGERATION CONTROL SYSTEMS AND METHODS FOR MODULAR COMPACT CHILLER UNITS - A controller for a modular compact chiller unit configured for integration into a refrigeration system utilizing a plurality of modular compact chiller units is shown and described. The controller includes a processing circuit configured to provide startup control, operational control, and shutdown control for the modular compact chiller unit. | 01-28-2010 |
20110167847 | FREE COOLING CASCADE ARRANGEMENT FOR REFRIGERATION SYSTEM - A refrigeration system includes a medium temperature subsystem circulating a coolant in a closed loop between at least one medium temperature chiller and at least one medium temperature load and at least one cascade heat exchanger, and a low temperature subsystem circulating a coolant in a closed loop between at least one low temperature heat exchanger and at least one low temperature load. A cooling circuit is provided for circulating a coolant and includes a first pump and a second pump and a fluid cooler and a valve, and interfaces with the medium temperature chiller and the low temperature chiller. The valve is movable to a closed position to define a first flow path and a second flow path, where the first flow path includes the first pump and the medium temperature chiller and fluid cooler, and the second flow path including the second pump and the low temperature heat exchanger and the cascade heat exchanger. | 07-14-2011 |
20110185757 | REFRIGERATION SYSTEM WITH MULTI-FUNCTION HEAT EXCHANGER - A refrigeration system with a multi-function heat exchanger has a first heat exchanger with an internal partition defining a condenser, a subcooler and an evaporator. An expansion device is located external of the heat exchanger and receives condensed refrigerant from the subcooler and provides expanded refrigerant to the evaporator. A compressor circulates the refrigerant through the condenser, the subcooler, and the evaporator. A secondary coolant circulates through the subcooler, the evaporator and the loads. A control system receives refrigerant temperature and pressure signals, and provides a control signal to the expansion device to maintain a temperature of the refrigerant within a predetermined range. A second heat exchanger cools a condensing fluid circulating through the condenser to condense the refrigerant. | 08-04-2011 |
20120117996 | CASCADE REFRIGERATION SYSTEM WITH MODULAR AMMONIA CHILLER UNITS - A cascade refrigeration system includes an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant mixed with a soluble oil circulates within the refrigerant circuit. A control device may be programmed to modulate the position of the expansion device so that a superheat temperature of the ammonia refrigerant near an outlet of the evaporator fluctuates within a substantially predetermined superheat temperature range to positively return soluble oil from the evaporator to the compressor. | 05-17-2012 |
20130091891 | CASCADE REFRIGERATION SYSTEM WITH MODULAR AMMONIA CHILLER UNITS - A cascade refrigeration system including an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant which may have entrained oil from the compressor circulates within the refrigerant circuit. An oil recycling circuit removes some oil from the ammonia refrigerant for return to the compressor. An oil pot collects oil accumulated in the evaporator and an oil return line drains oil from the oil pot to an ammonia accumulator or directly to the compressor. | 04-18-2013 |
20130263613 | SYSTEM AND METHOD FOR USING A PHOTOVOLTAIC POWER SOURCE WITH A SECONDARY COOLANT REFRIGERATION SYSTEM - A secondary coolant refrigeration system powered primarily by a photovoltaic source and by an alternating current (AC) source as a backup is disclosed. The secondary coolant refrigeration system has a pump for pumping secondary coolant fluid through a secondary coolant fluid loop. The system includes a variable frequency drive for controlling the speed of the pump. The variable frequency drive includes drive circuitry configured to provide variable frequency power to the pump via an output interface. The variable frequency drive also includes a first interface configured to receive power from the photovoltaic source and a second interface configured to receive power from the AC source. The circuit is further configured to cause the variable speed drive to be powered by the photovoltaic source when the power received from the first interface is adequate and by the AC source when the power received from the first interface is not adequate. | 10-10-2013 |
20140352343 | CO2 REFRIGERATION SYSTEM WITH HOT GAS DEFROST - A C02 refrigeration system has an LT system with LT compressors and LT evaporators, and an MT system with MT compressors and MT evaporators, operating in a refrigeration mode and a defrost mode using C02 hot gas discharge from the MT and/or the LT compressors to defrost the LT evaporators. A C02 refrigerant circuit directs C02 refrigerant through the system and has an LT compressor discharge line with a hot gas discharge valve, a C02 hot gas defrost supply header directing C02 hot gas discharge from the LT and/or the MT compressors to the LT evaporators, a flash tank supplying C02 refrigerant to the MT and LT evaporators during the refrigeration mode, and receiving the C02 hot gas discharge from the LT evaporators during the defrost mode, and a control system directing the C02 hot gas discharge through the LT evaporators and to the flash tank during the defrost mode. | 12-04-2014 |