Abstract: A cooling system has both pumped refrigerant economization and direct expansion cooling. When outside air temperature is low enough that pumped refrigerant economization can provide enough cooling to satisfy cooling demand, only pumped refrigerant economization cooling is used to provide cooling. When outside air temperature is low enough that pumped refrigerant economization can provide some but not all of the cooling needed to satisfy cooling demand, the pumped refrigerant economization is operated at one hundred percent capacity and the direct expansion cooling is operated at a capacity to provide any supplemental cooling that is needed. If the outside air temperature is high enough that pumped refrigerant economization cannot provide any cooling, then only direct expansion cooling is used to provide cooling.

Abstract: A cooling system for an equipment closet in a building has a direct expansion cooling circuit. The cooling system has two basic modes of operation. A first mode where the direct expansion cooling circuit is off and transfer air from an area of the building outside the equipment closet is used to cool the interior of the equipment closet without any cooling provided by the direct expansion cooling circuit and a second mode where the direct expansion cooling circuit is on and provides direct expansion cooling that is used to cool the interior of the equipment closet.

Abstract: A cooling system has both pumped refrigerant economization and direct expansion cooling. When outside air temperature is low enough that pumped refrigerant economization can provide enough cooling to satisfy cooling demand, only pumped refrigerant economization cooling is used to provide cooling. When outside air temperature is low enough that pumped refrigerant economization can provide some but not all of the cooling needed to satisfy cooling demand, the pumped refrigerant economization is operated at one hundred percent capacity and the direct expansion cooling is operated at a capacity to provide any supplemental cooling that is needed. If the outside air temperature is high enough that pumped refrigerant economization cannot provide any cooling, then only direct expansion cooling is used to provide cooling.

Abstract: A cooling system has both pumped refrigerant economization and direct expansion cooling. When outside air temperature is low enough that pumped refrigerant economization can provide enough cooling to satisfy cooling demand, only pumped refrigerant economization cooling is used to provide cooling. When outside air temperature is low enough that pumped refrigerant economization can provide some but not all of the cooling needed to satisfy cooling demand, the pumped refrigerant economization is operated at one hundred percent capacity and the direct expansion cooling is operated at a capacity to provide any supplemental cooling that is needed. If the outside air temperature is high enough that pumped refrigerant economization cannot provide any cooling, then only direct expansion cooling is used to provide cooling.

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: In an aspect, a cooling system has a cooling circuit that includes an evaporator, a condenser, a compressor, a sub-cooler and an expansion device configured in a direct expansion cooling circuit with the sub-cooler coupled in series between an outlet of the condenser and an inlet of the expansion device. The condenser has a micro-channel cooling coil and the sub-cooler has a fin-and-tube cooling coil. In an aspect, the fin-and-tube cooling coil of the sub-cooler has a total hydraulic volume equivalent to the total hydraulic volume of the micro-channel cooling coil of the condenser but the fin-and-tube cooling coil of the sub-cooler has a face area more than two times smaller than a face area of the micro-channel cooling coil of the condenser.

Abstract: A method including: determining a cooling value; and comparing the cooling value to an activation point of a lead compressor. The lead compressor is in a tandem set of scroll compressors of a cooling system. The tandem set of compressors comprises a lag compressor. The method further includes: activating the lead compressor when the cooling value is greater than the activation point; activating the lag compressor subsequent to activating the lead compressor; and determining whether conditions exist including: an alarm associated with the lag compressor being generated, and the lead compressor being deactivated. The method further includes deactivating the lag compressor when at least one of the conditions exists in the cooling system.

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 for an equipment closet in a building has a direct expansion cooling circuit. The cooling system has two basic modes of operation. A first mode where the direct expansion cooling circuit is off and transfer air from an area of the building outside the equipment closet is used to cool the interior of the equipment closet without any cooling provided by the direct expansion cooling circuit and a second mode where the direct expansion cooling circuit is on and provides direct expansion cooling that is used to cool the interior of the equipment closet.

Abstract: A cooling system has both pumped refrigerant economization and direct expansion cooling. When outside air temperature is low enough that pumped refrigerant economization can provide enough cooling to satisfy cooling demand, only pumped refrigerant economization cooling is used to provide cooling. When outside air temperature is low enough that pumped refrigerant economization can provide some but not all of the cooling needed to satisfy cooling demand, the pumped refrigerant economization is operated at one hundred percent capacity and the direct expansion cooling is operated at a capacity to provide any supplemental cooling that is needed. If the outside air temperature is high enough that pumped refrigerant economization cannot provide any cooling, then only direct expansion cooling is used to provide cooling.

Abstract: A method including determining whether an OFF criterion is satisfied for a lag compressor of a tandem set of scroll compressors. The tandem set of scroll compressors includes a lead compressor. The method further includes: initiating at least one process when the OFF criterion is satisfied; and maintaining the lag compressor in an ON state for a predetermined period subsequent to the OFF criterion being satisfied. The at least one process includes at least one of: operating the lead compressor at a maximum level; overriding a motor overload protection method, wherein the motor overload protection method protects motors of the lead compressor and the lag compressor; and overriding a proportional integral derivative (PID) method to reduce a speed of a condenser fan. The PID method controls the speed of the condenser fan. A system including the lag compressor module and the lead compressor module.

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: In an aspect, a cooling system has a cooling circuit that includes an evaporator, a condenser, a compressor, a sub-cooler and an expansion device configured in a direct expansion cooling circuit with the sub-cooler coupled in series between an outlet of the condenser and an inlet of the expansion device. The condenser has a micro-channel cooling coil and the sub-cooler has a fin-and-tube cooling coil. In an aspect, the fin-and-tube cooling coil of the sub-cooler has a total hydraulic volume equivalent to the total hydraulic volume of the micro-channel cooling coil of the condenser but the fin-and-tube cooling coil of the sub-cooler has a face area more than two times smaller than a face area of the micro-channel cooling coil of the condenser.

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 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 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 method including: determining a cooling value; and comparing the cooling value to an activation point of a lead compressor. The lead compressor is in a tandem set of scroll compressors of a cooling system. The tandem set of compressors comprises a lag compressor. The method further includes: activating the lead compressor when the cooling value is greater than the activation point; activating the lag compressor subsequent to activating the lead compressor; and determining whether conditions exist including: an alarm associated with the lag compressor being generated, and the lead compressor being deactivated. The method further includes deactivating the lag compressor when at least one of the conditions exists in the cooling system.

Abstract: A method including determining whether an OFF criterion is satisfied for a lag compressor of a tandem set of scroll compressors. The tandem set of scroll compressors includes a lead compressor. The method further includes: initiating at least one process when the OFF criterion is satisfied; and maintaining the lag compressor in an ON state for a predetermined period subsequent to the OFF criterion being satisfied. The at least one process includes at least one of: operating the lead compressor at a maximum level; overriding a motor overload protection method, wherein the motor overload protection method protects motors of the lead compressor and the lag compressor; and overriding a proportional integral derivative (PID) method to reduce a speed of a condenser fan. The PID method controls the speed of the condenser fan.

Abstract: In a cooling system having a plurality of identical cooling circuits, fault detection is determined by a controller if monitored operating parameters of the cooling circuits differ from each other by an appreciable amount. In an aspect, the controller uses a comparison of the operating parameters of a cooling circuit to a snapshot of the operating parameters of that cooling circuit taken after the cooling circuit is determined to be operating properly after start-up. In an aspect, the controller uses known operating parameters of a cooling circuit and a system model of the cooling circuit to calculate remaining operating parameters of the cooling circuit (system model operating parameters) and uses a comparison of the system model operating parameters to the monitored operating parameters.