Liebert Corporation

Vertiv Corporation

Roger Noll

Daniel J Schutte

Gary A Helmink

Lou Monnier

Zhiyong Lin

Benedict J Dolcich

John Francis Judge

Timothy J Schrader

Pierpaolo Barbato

Giuseppe Dalla Mana

Stephen C Sillato

Greg Haggy

Thomas Harvey

Zongtao Lu

Matthew Raven

John R Birchmeier

Stephen Sillato

The present disclosure relates to a method for controlling a level of superheat during a pump mode of operation of a refrigeration system, wherein the refrigeration system can operate in either the pump mode or a compressor mode, and has an electronically controlled expansion valve (EEV). A controller obtains a stored, predetermined pump differential pressure range able to be produced by a pump of the system. The controller also obtains a stored, predetermined superheat range, and detects a superheat level. When the detected superheat level is outside of the superheat temperature range, the controller commands adjusting at least one of the EEV and a speed of the pump based on whether the detected superheat level is above or below the superheat range, and whether a current pump differential pressure is above or below the predetermined pump differential pressure range.

System and method to maintain evaporator superheat during pumped refrigerant economizer operation

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.

High efficiency cooling system

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.

Scroll compressor differential pressure control during compressor startup transitions

A method includes determining a pressure difference across a scroll compressor of a cooling system. The pressure difference is compared to a minimum differential pressure value. Pressure differences across the scroll compressor that are less than the minimum differential pressure value are associated with unloading the scroll compressor. Parameters including a pressure set point value and an absolute minimum pressure value are increased when the pressure difference is less than the minimum differential pressure value. Subsequent to the increasing of the parameters, the parameters are decreased when the pressure difference is greater than a sum of the minimum differential pressure value and a hysteresis value.

Methods of controlling a cooling system based on pressure differences across a scroll compressor

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.

Scroll compressor differential pressure control during compressor shutdown transitions

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.

Multi-stage cooling system with tandem compressors and optimized control of sensible cooling and dehumidification

A cooling system has a tandem compressor, a condenser, an electronic expansion valve and an evaporator arranged in a direct expansion cooling circuit. The tandem compressor includes a variable capacity compressor and a fixed capacity compressor. A controller controls the electronic expansion valve and selects which of a plurality of superheat control modes to use in operating the electronic expansion valve based on control parameters and a current operating status of each of the variable capacity compressor and fixed capacity compressor of the tandem compressor.

Growing community of inventors

Gahanna, OH, United States of America

Roger Noll