Cooling, heating and power system with an integrated part-load, active, redundant chiller

Abstract

A cooling, heating and power system (10) includes a prime mover (12) for producing electricity having a thermal output (18) and an electrical output (20) coupled to an absorption chiller (24). A part-load, active, redundant chiller (26) is thermally coupled to the absorption chiller (24) for receiving a cooling-heating fluid from the absorption chiller (24). The part-load chiller (26) operates at maximum efficiency at between about forty percent and about sixty percent of a maximum cooling load of the chiller (26) to thereby generate large volumes of cooling very efficiently. The system (10) may direct the cooling into a multi-zone cooling-heating circuit (40) including a critical zone (42) and a utility zone (44) thermally coupled to the chiller (26) for selectively delivering the cooling-heating fluid to at least one of the critical zone (42) and the utility zone (44) of the circuit (40).

Description

CROSS REFERENCE TO RELATED APPLICATION [0001]This Application claims the benefit of U.S. Provisional Patent Application Ser. No. 61 / 069,276 that was filed on Mar. 12, 2008, entitled “Redundant Cooling Integrated with CHP”.TECHNICAL FIELD [0002]The present disclosure relates generally to use of cooling, heating and power systems (occasionally referred to as “CHP”, or “CCHP” for “combined cooling, heating and power”) that include a prime mover for producing electrical and / or mechanical energy that is thermally and electrically coupled with an absorption chiller for producing cooling and heating for such things as buildings having data centers, hospitals, etc. More particularly, the disclosure includes such a CHP system with an integrated part-load, active, redundant electric chiller and a system controller to provide more efficient cooling with a capacity for more efficient peak and back up cooling capacity.BACKGROUND ART [0003]Providing cooling, heating and power to modern structures...

AI Technical Summary

Benefits of technology

[0012]By integrating the part-load, active redundant chiller to operate downstream from the absorption chiller so that it receives the cooling-heating fluid after it has been cooled by the absorption chiller, the part-load, active redundant chiller may operate at a very high rate of efficiency compared to the part-load, active, redundant chiller operating alone to achieve a required decrease in temperature of the cooling-heating fluid. For example, if the circulating cooling-heating fluid must be reduced in temperature by a total of 10 degrees by the cooling, heating and power system, and the absorption chiller first reduces the temperature by 5 degrees, the part-load, active, redundant chiller can be sized to reduce the cooling-heating fluid the additional 5 degrees while operating at between about 40% to about 60% of its capacity or “load”, which is a highest efficiency operating point of the part-load, active, redundant chiller. (For purposes herein, the word “about” is to mean plus or minus 10%.) This permits the part-load, active, redundant chiller to operate at a very high rate of efficiency by reducing mechanical work required by the part-load, active, redundant chiller. Then, if operation of the absorption chiller is interrupted, the part-load, active, redundant chiller may be controlled to operate at about one-hundred percent load to satisfy the cooling demands of the critical zone. More importantly, during normal operation of the system, by having the electrically powered part-load, active, redundant chiller operate downstream from the absorption chiller, both chillers may be sized for minimal cost and maximum operating efficiency to thereby deliver cooling to the multi-zone cooling-heating circuit at a very low kilowatt per refrigeration ton (“kW / ton”) value, while providing enhanced cooling backup. In a preferred embodiment, the part-load, active, redundant chiller is a high efficiency, tri-screw electric chiller.

[0013]Integrating the part-load, active, redundant chiller downstream from the absorption chiller also permits efficient sizing of the absorption chiller so that the absorption chiller does not have to be substantially over sized beyond normal load conditions to meet peak loads described above. Instead, the part-load, active, redundant chiller is dimensioned to be responsive to normal loads on the system while operating at between about 40% to about 60% load, and during peak load conditions, the part-load, active, redundant chiller is controlled to increase cooling capacity to meet the peak load conditions. If operation of the absorption chiller is interrupted producing offnormal load conditions, the part-load, active, redundant chiller may be controlled to increase its cooling capacity from the efficient 40% to 60% load to a load between about 60% and 100% to meet the offnormal condition. Integration of the part-load, active, redundant chiller with the absorption chiller and prime mover therefore provides enormous efficiencies in manufacture, cost and operation of the cooling, heating and power system of the present disclosure.

Problems solved by technology

A CHP system with a prime mover that is electrically and thermally coupled to an absorption chiller nonetheless gives rise to substantial concerns.

Alternatively if operation of the prime mover was interrupted, the absorption chiller depending upon the waste heat from the prime mover, would then also be unable to operate, again requiring the overall cooling supply of the structure to include alternative backup cooling sources.

For example, during a heat wave in a metropolitan area, it is known that a grid supply may suffer “brown-outs” while cooling demand is at an absolute peak due to the heat wave.

Design of a CHP system to satisfy such a circumstance mandates that the absorption chiller be uneconomically sized to perform occasionally at outputs substantially beyond normal load operations.

This adds further cost and complexity to the CHP system and to an overall system that provides all of the cooling, heating and power demands of the structure.

In the event operation of the prime mover is interrupted which would terminate the thermal flow from the prime mover into the absorption chiller thereby disrupting operation of the absorption chiller, the part-load, active, redundant chiller may continue to operate while receiving electricity from an alternative source outside of the cooling, heating and power source, such as the external grid supply of electricity.

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