Liebert Corporation

Greg Haggy

Stephen C Sillato

Timothy J Schrader

John Francis Judge

Zhiyong Lin

Benedict J Dolcich

Daniel J Schutte

Roger Noll

Gary A Helmink

Lou Monnier

Pierpaolo Barbato

Giuseppe Dalla Mana

Zongtao Lu

Thomas Harvey

Stephen Sillato

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 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.

Load estimator for control of vapor compression cooling system with pumped refrigerant economization

A cooling system includes a cooling circuit having an evaporator, a condenser, a compressor, an expansion device, a liquid pump, and a receiver/surge tank coupled between the condenser and the liquid pump. The cooling system has a direct expansion mode and a pumped refrigerant economizer mode. When the cooling system switches from the direct expansion mode to the pumped refrigerant economizer mode, refrigerant is flushed from the refrigerant/surge tank so that the cooling circuit is overcharged when it begins operating in the pumped refrigerant economizer mode.

Receiver tank purge in vapor compression cooling system with pumped refrigerant economization

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Gahanna, OH, United States of America

Greg Haggy