Microelectronics cooling system

Abstract

In one general aspect, a microelectronics cooling device can include a microchannel heat exchanger within an enclosure that houses the device at a heat absorbing end and another heat exchanger which is optionally also a microchannel heat exchanger at a heat sink end outside the enclosure. One or more pipes flowably connect the two ends for transporting liquid working fluid to the heat absorber and vaporized working fluid to the heat sink. The heat pipes may also be used to transfer heat outside a room that contains the electronic devices.

1 . A microelectronics cooling system, comprising:
 a) a microchannel heat absorber located proximate a microelectronic device within an electronic device enclosure and comprising at least one layer defining a plurality of microchannels having a cross-sectional dimension of less than 1000 microns and terminating at a first end thereof in a cool side manifold and at a second end thereof in a warm side manifold, the microchannels adapted to contain a liquid working fluid that absorbs heat from the microelectronic device and forms a vapor upon flowing therethrough from the first end to the second end,   b) a heat sink located outside of the enclosure for receiving and condensing the vapor to reform the liquid working fluid and for discharging the liquid working fluid, and   c) one or more pipes flowably connecting the warm side manifold of the heat absorber to the heat sink and flowably connecting the cool side manifold of the heat absorber to the heat sink, wherein the one or more pipes are connected so as to permit simultaneous flow of the vapor from the heat absorber to the heat sink and of the liquid working fluid from the heat sink to the heat absorber when heat is applied to the heat absorber.   
     
     
         2 . The microelectronics cooling system of  claim 1 , wherein the heat sink is installed outside of a room housing the electronic device enclosure. 
     
     
         3 . The microelectronics cooling system of  claim 1  wherein the heat sink is installed in a cooling duct that flows to a location outside of a room housing the electronic device enclosure, wherein a cooling medium flowing through the duct includes air or water. 
     
     
         4 . The microelectronics cooling system of  claim 1 , wherein the one or more pipes comprises a first pipe flowably connecting the warm side manifold of the heat absorber to the heat sink and a second pipe flowably connecting the cool side manifold of the heat absorber to the heat sink. 
     
     
         5 . The microelectronics cooling system of  claim 1 , wherein the one or more pipes comprises only a single pipe. 
     
     
         6 . The microelectronics cooling system of  claim 1 , wherein the single pipe comprises a porous coaxial wick. 
     
     
         7 . The microelectronics cooling system of  claim 1 , wherein the single pipe comprises an annular band of a porous wicking material. 
     
     
         8 . The microelectronics cooling system of  claim 1 , wherein the heat sink is a microchannel heat sink. 
     
     
         9 . The microelectronics cooling system of  claim 1 , wherein the microchannels are substantially rectangular channels, wherein the cross-sectional dimension of the microchannels is a shorter of two different cross-sectional dimensions for the microchannels, and wherein the shorter cross-sectional dimensions are aligned perpendicular to a surface of a heat source. 
     
     
         10 . The microelectronics cooling system of  claim 1 , wherein the microchannel heat absorber is a parallel flow microchannel heat absorber. 
     
     
         11 . The microelectronics cooling system of  claim 1 , wherein the microchannel heat absorber is a cross-flow microchannel heat absorber. 
     
     
         12 . The microelectronics cooling system of  claim 1 , wherein the thermal conductivity of material in the layer that defines the microchannels is greater than 170 watts/m-° C. and the microchannels have a largest cross-sectional dimension of less than 250 microns. 
     
     
         13 . The microelectronics cooling system of  claim 1 , wherein the heat pipe is entirely passive. 
     
     
         14 . The microelectronics cooling system of  claim 1 , wherein the thermal coupling of the microelectronic device to the heat absorber is achieved by using the heat absorber as the substrate for one or more layers of active microelectronic elements. 
     
     
         15 . The microelectronics cooling system of  claim 1 , wherein the microchannel heat absorbers comprise channels integrally fabricated within a semiconductor substrate of the microelectronic devices, such as a silicon substrate, to facilitate the direct transfer and removal of heat from within the microelectronic device to the working fluid. 
     
     
         16 . The microelectronics cooling system of  claim 15  further comprising at least one more integrated microelectronic devices and at least one more microchannel heat absorber, wherein the microchannel heat absorbers are connected via common manifolds to the heat sink, and wherein the heat sink is of sufficient size to reject the combined heat load of the multiply connected integrated microelectronic devices and microchannel heat absorbers. 
     
     
         17 . The microelectronics cooling system of  claim 15 , wherein multiple layers of microelectronic components fabricated within an integrated assembly are cooled by interspersing one or more layers or the microchannel fabricated within the integrated multi-layer device, facilitating the direct transfer and removal of heat from within the multiple microelectronic devices to the working fluid. 
     
     
         18 . The microelectronics cooling system of  claim 17  further comprising at least one more multi-layered microelectronic devices and at least one more microchannel heat absorber, wherein the microchannel heat absorbers are connected via common manifolds to the heat sink, and wherein the heat sink is of sufficient size to reject the combined heat load of the multiply connected integrated microelectronic devices and microchannel heat absorbers. 
     
     
         19 . The microelectronics cooling system of  claim 1  further comprising at least one more microelectronic device and at least one more microchannel heat absorber, wherein the microchannel heat absorbers are connected via common manifolds to the heat sink, and wherein the heat sink is of sufficient size to reject the combined heat load of the multiply connected microelectronic devices and microchannel heat absorbers. 
     
     
         20 . A microelectronics cooling system comprising two or more of multi-layer integrated microelectronic devices and microchannel heat absorbers of  claim 16 , are connected via common manifolds to the heat sink of  claim 16 , wherein the heat sink is of sufficient size to reject the combined heat load of the multiply connected microelectronic devices and microchannel heat absorbers. 
     
     
         21 . A method of cooling a microelectronic device housed inside an enclosure, comprising:
 i) providing
 a) a microchannel heat absorber comprising at least one layer defining a plurality of microchannels having a cross-sectional dimension of less than 1000 microns and terminating at a first end thereof in a cool side manifold and at a second end thereof in a warm side manifold, the microchannels containing a liquid working fluid that absorbs heat and forms a vapor upon flowing therethrough from the first end to the second end, 
 b) a heat sink for receiving and condensing the vapor to reform the liquid working fluid and for discharging the liquid working fluid, and 
 c) one or more pipes flowably connecting the warm side manifold of the heat absorber to the heat sink and flowably connecting the cool side manifold of the heat absorber to the heat sink, wherein the one or more pipes are connected so as to permit simultaneous flow of the vapor from the heat absorber to the heat sink and of the liquid working fluid from the heat sink to the heat absorber when heat is applied to the heat absorber, 
   ii) installing the microchannel heat absorber inside the enclosure, and   iii) installing the heat sink outside the enclosure.   
     
     
         22 . The microelectronics cooling method of  claim 4 , wherein the step of providing provides a heat sink that is installed outside of a room housing the electronic device enclosure or in a cooling duct that flows to a location outside of the room, and wherein the cooling medium flowing through the duct is air or water. 
     
     
         23 . The microelectronics cooling method of  claim 4 , wherein the step of providing provides the layer that defines the microchannels with a thermal conductivity that is greater than 170 watts/m-° C. and the microchannels have a largest cross-sectional dimension of less than 250 microns. 
     
     
         24 . The microelectronics cooling method of  claim 4 , wherein the step of providing provides an entirely passive microelectronics cooling system. 
     
     
         25 . A method of cooling a microelectronic device housed inside an enclosure, comprising
 causing a liquid working fluid to flow through a plurality of microchannels that are proximate the microelectronic device within a microelectronic device enclosure and having a cross-sectional dimension to the center of the channel that is about equal to or less than the thermal boundary layer thickness for a working fluid,   causing at least some of the working fluid to form a vapor and absorb heat from the microelectronic device,   receiving and condensing the working fluid vapor to discharge heat from the fluid outside the enclosure and reform the liquid working fluid, and   continuously returning the condensed working fluid from outside of the enclosure back into the enclosure.   
     
     
         26 . The microelectronics cooling method of  claim 25 , wherein the step of causing the working fluid to form a vapor takes place in the microchannels. 
     
     
         27 . The microelectronics cooling method of  claim 25 , wherein the step of condensing takes place in the microchannels. 
     
     
         28 . The microelectronics cooling method of  claim 25 , wherein the working fluid is conveyed substantially only passively. 
     
     
         29 . A microelectronics cooling system, comprising:
 means for absorbing heat from a microelectronic device in a microelectronic device enclosure through evaporation of a working fluid by a plurality of microchannels that are proximate the microelectronic device within the enclosure and having a cross-sectional dimension to the center of the channel that is about equal to or less than the thermal boundary layer thickness for a working fluid,   means for receiving and condensing the working fluid vapor to discharge heat from the fluid outside the enclosure and reform the liquid working fluid, and   means for continuously returning the condensed working fluid from outside of the enclosure back into the enclosure.   
     
     
         30 . The microelectronics cooling system of  claim 29 , wherein the means for continuously returning the working fluid operates substantially only passively.