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US 7,581,515 B2Granted
Control scheme for an evaporator operating at conditions approaching thermodynamic limits
AssigneeHamilton Sundstrand Corporation
InventorEdward W. O'Connor
Life of this patent
Estimating the term…
Abstract
A heat exchanger assembly includes a plurality of evaporative heat exchangers that are selectively feed evaporant to tailor operation to current heat load in order to maintain operation in thermodynamically extreme operating conditions.
Claims17
A method of controlling an evaporative heat exchanger assembly comprising the steps of:
- a) directing a heat carrying medium through a plurality of evaporative heat exchangers in series;
- b) determining a temperature of the heat carrying medium at an inlet to the plurality of evaporative heat exchangers;
- c) directing a liquid evaporant separately through each of the evaporative heat exchangers that vaporizes while accepting heat from the heat carrying medium;
- d) exhausting the vaporized evaporant from each active one of the plurality of evaporative heat exchangers;
- and
- e) selectively controlling evaporant flow to each of the plurality of evaporative heat exchangers responsive to the temperature of the heat carrying medium at the inlet to mitigate potential freezing of the evaporant within each of the plurality of evaporative heat exchangers.
3 more elements
An evaporative heat exchanger assembly comprising:
- a plurality of evaporative heat exchanger cores each including an evaporant inlet, an evaporant exhaust, and an inlet for receiving a heat transfer medium, wherein subsequent ones of the evaporative heat exchangers receive heat transfer medium from a preceding one of the plurality of evaporative heat exchangers such that the heat transfer medium flows through each of the plurality of heat exchangers in series;
- an evaporant control valve associated with each of the plurality of heat exchangers for controlling evaporant flow;
- a variable control valve for controlling evaporant flow to each of the evaporant control valves;
- an inlet temperature sensor disposed at the inlet for receiving the heat transfer medium;
- and
- a controller for actuating the evaporant control valves and the variable control valve responsive to a temperature of the heat transfer medium measured by the inlet temperature sensor to maintain a desired pressure at the evaporant exhaust of each of the plurality of evaporative heat exchanger to prevent freezing of the evaporant flow within each of the plurality of evaporative heat exchangers.
3 more elements
Dependencies are inferred from the claim text.