Abstract: A system including a setpoint module, a summer, a control module, and an expansion valve module. The setpoint module is configured to indirectly control sub-cooling of a condenser by adjusting a superheat setpoint based on (i) a return air temperature setpoint or a supply air temperature setpoint, and (ii) an outdoor ambient temperature. The summer is configured to determine an error between the superheat setpoint and a superheat level of a compressor. The control module is configured to generate a control signal based on the error. The expansion valve module is configured to electronically control a state of an expansion valve based on the control signal.

Abstract: A cooling system has a cabinet and a plurality of separate cooling stages including an upstream cooling stage and a downstream cooling stage. At least the upstream cooling state is a variable capacity cooling stage. Each cooling stage has a cooling circuit. Evaporators of the cooling circuits are arranged in the cabinet so that air passes over them in serial fashion. A controller when a Call for Cooling first reaches a point where cooling is needed, operating the upstream cooling circuit to provide cooling and not the downstream cooling circuit. When the Call for Cooling has increased to a second point, the controller additionally operates the downstream cooling circuit to provide cooling. The cooling capacity at which the upstream cooling circuit is being operated is less than its full capacity when the Call for Cooling reaches the second point.

Abstract: A cooling system has a direct expansion mode and a pumped refrigerant economizer mode and a controller. The controller includes a load estimator that estimates real-time indoor load on the cooling system and uses the estimated real-time indoor load to determine whether to operate the cooling system in the pumped refrigerant economizer mode or in the direct expansion mode.

Abstract: A system includes an error module configured to integrate a difference between a superheat signal and a superheat setpoint to generate an error signal, wherein the superheat signal indicates suction superheat values of a compressor. A comparison module is configured to compare the error signal to a first predetermined threshold to generate a first comparison signal based on the comparison. A zero-crossing module is configured to compare a first count value to a second predetermined threshold to generate a second comparison signal. The first count value is generated based on at least one comparison between the superheat signal and the superheat setpoint. A setpoint module is configured to adjust the superheat setpoint based on the first comparison signal and the second comparison signal.

Abstract: A cooling system has a plurality of separate cooling stages including an upstream cooling stage having an upstream cooling circuit and a downstream cooling stage including a downstream cooling circuit, which are each a direct expansion cooling circuit including a tandem compressor. Each tandem compressor includes a fixed capacity compressor and a variable capacity compressor. A controller controls the fixed capacity compressor and variable capacity compressor of each tandem compressor based on a Call for Cooling, which of a plurality of ranges the Call for Cooling falls within, and whether the Call for Cooling is ramping up or ramping down.

Abstract: A cooling system has a cooling circuit that includes an evaporator disposed in a cabinet, a condenser, a compressor, a liquid/vapor separator tank and a liquid pump. The cooling circuit has a mode wherein the compressor and liquid pump are both on with the liquid pump pumping refrigerant through the evaporator with the refrigerant leaving the evaporator circulated to an inlet of the liquid/vapor separator tank and not to an inlet of the condenser. The cooling circuit also has a pumped refrigerant economizer mode wherein the liquid pump is on and the compressor is off and bypassed with the refrigerant leaving the evaporator circulated to the inlet of the condenser and not to the inlet of the liquid/vapor separator tank.

Abstract: A cooling system has a cabinet and a plurality of separate cooling stages including an upstream cooling stage and a downstream cooling stage. At least the upstream cooling state is a variable capacity cooling stage. Each cooling stage has a cooling circuit. Evaporators of the cooling circuits are arranged in the cabinet so that air passes over them in serial fashion. A controller when a Call for Cooling first reaches a point where cooling is needed, operating the upstream cooling circuit to provide cooling and not the downstream cooling circuit. When the Call for Cooling has increased to a second point, the controller additionally operates the downstream cooling circuit to provide cooling. The cooling capacity at which the upstream cooling circuit is being operated is less than its full capacity when the Call for Cooling reaches the second point.

Abstract: An air conditioner system including a condenser fan, an ambient temperature sensor, a refrigerant pressure sensor, and a controller. The ambient temperature sensor is to sense ambient temperature at the system. The refrigerant pressure sensor is to sense pressure of a refrigerant of the system. The target refrigerant pressure module is to identify an optimum pressure of the refrigerant in the system. The controller is to generate an output representing a speed of the condenser fan operable to maintain the pressure of the refrigerant at about the optimum pressure as the ambient temperature of the system changes.

Abstract: A cooling system has a cabinet and a plurality of separate cooling stages including an upstream cooling stage and a downstream cooling stage. At least the upstream cooling state is a variable capacity cooling stage. Each cooling stage has a cooling circuit. Evaporators of the cooling circuits are arranged in the cabinet so that air passes over them in serial fashion. A controller when a Call for Cooling first reaches a point where cooling is needed, operating the upstream cooling circuit to provide cooling and not the downstream cooling circuit. When the Call for Cooling has increased to a second point, the controller additionally operates the downstream cooling circuit to provide cooling. The cooling capacity at which the upstream cooling circuit is being operated is less than its full capacity when the Call for Cooling reaches the second point.

Abstract: A cooling system has a cooling circuit that includes an evaporator disposed in a cabinet, a condenser, a compressor, an electronic expansion valve and a liquid pump. a direct expansion mode and a pumped refrigerant economizer mode. When the cooling system is in the pumped refrigerant economizer mode, the controller controls a temperature of the refrigerant to a refrigerant temperature set point by regulating a speed of a fan of the condenser, controls a temperature of air in a room in which the cabinet is disposed to a room air temperature setpoint by regulating a speed of the liquid pump, and maintains a pressure differential across the liquid pump within a given range by regulating an open position of an electronic expansion valve.

Abstract: A cooling system has a plurality of separate cooling stages including an upstream cooling stage having an upstream cooling circuit and a downstream cooling stage including a downstream cooling circuit, which are each a direct expansion cooling circuit including a tandem compressor. Each tandem compressor includes a fixed capacity compressor and a variable capacity compressor. A controller controls the fixed capacity compressor and variable capacity compressor of each tandem compressor based on a Call for Cooling, which of a plurality of ranges the Call for Cooling falls within, and whether the Call for Cooling is ramping up or ramping down.

Abstract: A variable flow refrigerant system having a compressor and one or a plurality of evaporators. The suction at one or the plurality of evaporators for the input to the compressor is monitored and generally corresponds to the minimum pressure of the refrigerant. The pressure is associated with a temperature and is controlled to always be above the dew point temperature of the room.

Abstract: A universal control panel for controlling operation of a cooling component. The universal control panel may have a variable frequency drive (VFD) that incorporates an input voltage and frequency sensing circuit; and logic, memory and communications circuits. The VFD accepts a plurality of differing input signals, analyzes the input signals and generates an output signal having a desired voltage and frequency to provide real time control over an electrical component operably associated with the cooling component. The VFD controls the cooling component in relation to changes in at least one of sensed pressure and a sensed temperature of a fluid, to dampen response of the electrical component, to thus achieve more efficient use of the cooling component being used to cool the fluid.

Abstract: A universal control panel for controlling operation of a cooling component. The universal control panel may have a variable frequency drive (VFD) that incorporates an input voltage and frequency sensing circuit; and logic, memory and communications circuits. The VFD accepts a plurality of differing input signals, analyzes the input signals and generates an output signal having a desired voltage and frequency to provide real time control over an electrical component operably associated with the cooling component. The VFD controls the cooling component in relation to changes in at least one of sensed pressure and a sensed temperature of a fluid, to dampen response of the electrical component, to thus achieve more efficient use of the cooling component being used to cool the fluid.

Abstract: A liquid refrigerant drainage mechanism is described for use in a flooded evaporator to mitigate liquid carryover. The drainage mechanism can trap liquid refrigerant droplets, create a liquid column to overcome a pressure difference across the mechanism and drain liquid back to the pool in the evaporator. The drainage mechanism is disposed in a suction baffle, and has a mesh pad and a tapered pipe secured to the bottom of the baffle. The pipe has a drainage aperture at one end to allow the accumulated liquid refrigerant to return to the refrigerant pool below. The mesh pad helps to separate liquid droplets that coalesce and fall into the tapered pipe. By using this liquid drainage mechanism in conjunction with a suction baffle, liquid carryover can be reduced and chiller performance improved.

Abstract: A liquid refrigerant drainage mechanism is described for use in a flooded evaporator to mitigate liquid carryover. The drainage mechanism can trap liquid refrigerant droplets, create a liquid column to overcome a pressure difference across the mechanism and drain liquid back to the pool in the evaporator. The drainage mechanism is disposed in a suction baffle, and has a mesh pad and a tapered pipe secured to the bottom of the baffle. The pipe has a drainage aperture at one end to allow the accumulated liquid refrigerant to return to the refrigerant pool below. The mesh pad helps to separate liquid droplets that coalesce and fall into the tapered pipe. By using this liquid drainage mechanism in conjunction with a suction baffle, liquid carryover can be reduced and chiller performance improved.

Abstract: A software module for a building automation system includes a plurality of software modules. A first module is configured to compute energy consumption characteristics of a building. A second module is configured to determine at least one alternate hardware configuration for the building, and to provide an estimated performance level associated with each of the at least one alternate hardware configuration. A third module is configured to recommend one of the at least one hardware configurations based on at least one predetermined financial criteria.

Abstract: In a closed loop refrigerant system and method, a refrigerant liquid filter is provided downstream of the condenser to receive and clean high pressure, high temperature liquid refrigerant. The invention provides means for cooling liquid refrigerant so as to render otherwise soluble contaminants insoluble before leaving the filter. The means for cooling preferably includes a refrigerant line provided in thermal contact with the liquid refrigerant in the filter. The refrigerant line contains expanded refrigerant gas or expanded liquid/gas mixture, which is at a lower temperature than the liquid refrigerant received from the condenser. Condensed liquid refrigerant is provided to the filter, which filter further includes a filter element for removing contaminants that have been rendered insoluble by the cooling of the liquid refrigerant.

Abstract: A system and method are provided for variable speed operation of a screw compressor to obtain increased capacity and efficiency. The screw compressor is connected to an induction motor driven by a variable speed drive, wherein the screw compressor has a variable output capacity that is dependent on the output speed of the motor. To obtain increased capacity and efficiency, the screw compressor is operated at a speed greater than the screw compressor's rated speed and does not include a slide valve. The maximum operating speed of the screw compressor, which speed is greater than the rated speed, is related to the maximum operating speed of the motor when operated at a voltage and frequency provided by the variable speed drive that is greater than the motor's rated voltage and frequency in a constant flux or constant volts/Hz mode.

Abstract: A chiller system includes a refrigerant loop, the refrigerant loop further including a compressor, an air-cooled condenser arrangement and an evaporator arrangement connected in a first closed refrigerant loop. A motor is connected to the compressor to drive the compressor, a drive is connected to the motor to power the motor and a power/control panel controls the refrigerant loop. The power/control panel and the condenser arrangement are connected in a second closed coolant loop. The second closed coolant loop provides cooling to the enclosure and/or components within the enclosure disposed on a chill plate. Condensation is substantially prevented from forming inside the enclosure, despite the enclosure lacking a humidity control device.