Closed-loop microchannel cooling system
First Claim
1. A closed-loop fluid cooling system for a heat-generating device comprising:
- a powered pump for pumping the fluid through the closed-loop system;
a temperature control circuit capable of regulating a device temperature by adjusting a fluid flow rate;
a first heat exchanger including an enclosed microchannel and coupled to the heat-generating device for transferring heat to the fluid, the fluid entering the heat exchanger in a liquid state and exiting in a liquid-vapor state, wherein the microchannel has a cross section, defined by a width and a height, that varies along a length thereof to reduce a temperature variation along the length when compared to a microchannel having a constant cross section;
a second heat exchanger coupled to ambient for transferring heat from the fluid to an external environment; and
wherein the static pressure is below the ambient pressure in at least one location in the closed-loop.
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Accused Products
Abstract
Apparatus and methods according to the present invention utilize micropumps that are capable of generating high pressure and flow without moving mechanical parts and the associated generation of unacceptable electrical and acoustic noise, as well as the associated reduction in reliability. These micropumps are fabricated with materials and structures that improve performance, efficiency, and reduce weight and manufacturing cost relative to presently available micropumps. These micropumps also can allow for recapture of evolved gases and deposited materials, which may provide for long-term closed-loop operation. Apparatus and methods according to the present invention also allow active regulation of the temperature of the device through electrical control of the flow through the pump and can utilize multiple cooling loops to allow independent regulation of the spatial and temporal characteristics of the device temperature profiles. Novel enclosed microchannel structures are also described.
323 Citations
37 Claims
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1. A closed-loop fluid cooling system for a heat-generating device comprising:
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a powered pump for pumping the fluid through the closed-loop system; a temperature control circuit capable of regulating a device temperature by adjusting a fluid flow rate; a first heat exchanger including an enclosed microchannel and coupled to the heat-generating device for transferring heat to the fluid, the fluid entering the heat exchanger in a liquid state and exiting in a liquid-vapor state, wherein the microchannel has a cross section, defined by a width and a height, that varies along a length thereof to reduce a temperature variation along the length when compared to a microchannel having a constant cross section; a second heat exchanger coupled to ambient for transferring heat from the fluid to an external environment; and wherein the static pressure is below the ambient pressure in at least one location in the closed-loop. - View Dependent Claims (2, 3, 4)
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5. A closed-loop cooling system for a heat-generating device, comprising:
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a powered pump; a substrate including at least a portion of a microchannel enclosed therein, the microchannel having a varying cross-sectional dimension between an inlet and an outlet, the substrate disposed on the heat-generating device to transfer thermal energy from the heat-generating device to the substrate, and the further transfer of thermal energy to a fluid disposed within the microchannel; and wherein the microchannel is configured to provide flow of the fluid therethrough, wherein the microchannel cross section, defined by a width and a height, varies along a length of the microchannel so as to reduce an overall pressure drop when compared to the pressure drop that occurs with a microchannel having fixed dimensions. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for transferring heat from a heat-generating device to a heat exchanger in a closed-loop cooling system including a powered pump, the heat exchanger including an enclosed microchannel having a varying cross-section that can transfer a fluid therethrough, the fluid entering the microchannel in a liquid state and exiting in a liquid-vapor state, the method comprising the steps of:
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determining a plurality of dimensions of the microchannel such that the fluid exits at sub-atmospheric pressure and sufficient thermal energy is transferred to the fluid to maintain the temperature of the heat-generating device below an operational limit; wherein the step of determining the plurality of dimensions includes selecting a cross section, defined by a width and a height, that varies with position along a length of the microchannel; and coupling the microchannel with the determined dimensions to the heat-generating device. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An apparatus for use with a closed-loop cooling system, including a powered pump, that operates using a fluid having both a liquid phase and a liquid-vapor phase, comprising:
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a heat generating device including a heat generating element and a temperature control circuit, wherein the temperature control circuit is capable of regulating a device temperature by adjusting a fluid flow rate; a substrate physically connected to the heat generating device, the substrate enclosing at least a portion of a microchannel and providing for the transfer of thermal energy to the fluid disposed within the microchannel, the microchannel configured to provide flow of the fluid through the microchannel, wherein the fluid is in the liquid phase when entering and in the liquid-vapor phase when exiting the microchannel. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification