Demand flow pumping
First Claim
1. A method for efficient operation of a chilled water plant comprising:
- identifying a pre-determined chilled water Delta T;
setting a chilled water Delta T based on the pre-determined chilled water Delta T, the chilled water Delta T comprising a chilled water entering temperature and a chilled water leaving temperature at one or more components of the chilled water plant;
controlling chilled water flow rate through the one or more components to maintain the chilled water Delta T across the one or more components, wherein the chilled water flow rate is controlled by one or more chilled water pumps; and
performing a critical zone reset to adjust the chilled water Delta T when one or more triggering events occur, wherein the chilled water Delta T is reset by an action selected from the group consisting of adjusting the chilled water entering temperature and adjusting the chilled water leaving temperature;
wherein the control of chilled water flow rate through the one or more components to maintain the chilled water Delta T reduces Low Delta T Syndrome at the chilled water plant.
2 Assignments
0 Petitions
Accused Products
Abstract
Demand Flow operates chilled water plants at substantially improved efficiency, regardless of plant load conditions. In general, Demand Flow utilizes an operating strategy which controls chilled and condenser water pumping according to a constant Delta T line, which is typically near or at design Delta T. This reduces or eliminates Low Delta T Syndrome and reduces energy usage by chilled and condenser water pumps for given load conditions. Operation of chilled water pumps in this manner creates a synergy which generally balances flow rates throughout the plant, reducing undesirable bypass mixing and energy usage at air handler fans and other components of the chilled water plant. At plant chillers, application of Demand Flow increases the refrigeration effect through refrigerant sub-cooling and superheating, while preventing stacking. Demand Flow includes a critical zone reset feature which allows the constant Delta T line to be reset to adjust to changing load conditions.
57 Citations
20 Claims
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1. A method for efficient operation of a chilled water plant comprising:
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identifying a pre-determined chilled water Delta T; setting a chilled water Delta T based on the pre-determined chilled water Delta T, the chilled water Delta T comprising a chilled water entering temperature and a chilled water leaving temperature at one or more components of the chilled water plant; controlling chilled water flow rate through the one or more components to maintain the chilled water Delta T across the one or more components, wherein the chilled water flow rate is controlled by one or more chilled water pumps; and performing a critical zone reset to adjust the chilled water Delta T when one or more triggering events occur, wherein the chilled water Delta T is reset by an action selected from the group consisting of adjusting the chilled water entering temperature and adjusting the chilled water leaving temperature; wherein the control of chilled water flow rate through the one or more components to maintain the chilled water Delta T reduces Low Delta T Syndrome at the chilled water plant. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A controller for controlling one or more pumps of a chilled water plant comprising:
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an input configured to receive sensor information from one or more sensors; a processor configured to control a flow rate provided by the one or more pumps to maintain a Delta T across a component of the chilled water plant, wherein the processor increases or decreases the flow rate to maintain the Delta T based on the sensor information and generates one or more signals to control the flow rate provided by the one or more pumps, the Delta T comprising an entering temperature and a leaving temperature; and
wherein the processor is configured to perform a critical zone reset by lowering the Delta T in response to sensor information indicating additional cooling capacity is desired at the component; andan output configured to send the one or more signals to the one or more pumps. - View Dependent Claims (8, 9, 10, 11)
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12. A method for efficient operation of a chilled water plant comprising:
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setting a chilled water Delta T comprising a chilled water entering temperature and a chilled water leaving temperature at one or more components of the chilled water plant; controlling chilled water flow rate through the one or more components to maintain the chilled water Delta T across the one or more components, wherein the chilled water flow rate is controlled by one or more chilled water pumps; and performing a critical zone reset to adjust the chilled water Delta T when one or more triggering events occur, wherein the chilled water Delta T is reset by an action selected from the group consisting of adjusting the chilled water entering temperature and adjusting the chilled water leaving temperature; wherein the control of chilled water flow rate through the one or more components to maintain the chilled water Delta T reduces Low Delta T Syndrome at the chilled water plant, and wherein the chilled water Delta T at the one or more chilled water plant components is maintained by increasing the chilled water flow rate or decreasing the chilled water flow rate. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification