High efficiency flat panel microchannel heat exchanger

Abstract

An apparatus providing high efficiency heat exchange between two fluids is disclosed. The apparatus most commonly comprises a flat panel with microchannels directing the flow of the two fluids, specifically: with a small hydraulic diameter in order to increase the heat transfer effect; while, at the same time, the flow length and cross-section of the microchannels are controlled to reduce the pressure losses normally associated with such small hydraulic diameters.

1 . A heat exchanger for transferring heat between a first fluid and a second fluid, comprising: 
 a. A first set of fluid channels through which the first fluid may flow, in which each channel is substantially identical to the others in cross sectional dimensions and length; and    b. A second set of fluid channels through which the second fluid may flow; each channel having a flow length less than 8.0 mm; and having a value of said channel flow length divided by the square of the channel hydraulic diameter between 5 mm −1  and 30 mm − .    
   
   
       2 . The heat exchanger as recited in  claim 1 , in which each channel of the second set of fluid channels has a length less than 4.0 mm.  
   
   
       3 . The heat exchanger as recited in  claim 1 , in which the second set of fluid channels directs the second fluid flow in paths which are not parallel to the first set of fluid channels.  
   
   
       4 . The heat exchanger as recited in  claim 1 , in which the second set of fluid channels is comprised of individual channels, each with a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       5 . The heat exchanger as recited in  claim 3 , in which the second set of fluid channels is comprised of individual channels, each with a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       6 . The heat exchanger as recited in  claim 1 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       7 . The heat exchanger as recited in  claim 3 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       8 . The heat exchanger as recited in  claim 7 , in which the individual channels of the second set of fluid channels each have a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       9 . The heat exchanger as recited in  claim 7 , in which the cross section of each channel of the second set of fluid channels is oriented so that its longest side is substantially parallel to the direction of fluid flow through the first set of fluid channels.  
   
   
       10 . The heat exchanger as recited in  claim 9 , in which the cross section of each channel of the second set of fluid channels has a smallest dimension measuring between 0.125 mm and 1.0 mm.  
   
   
       11 . The heat exchanger as recited in  claim 1 , in which the first set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       12 . The heat exchanger as recited in  claim 11 , in which the cross section of each channel of the first set of fluid channels has a longest side substantially parallel to the direction of the fluid flow through the second set of fluid channels.  
   
   
       13 . The heat exchanger as recited in  claim 1 , in which the first set of fluid channels is arranged substantially in a single plane, defined by the general direction of fluid flow through said first set of fluid channels.  
   
   
       14 . The heat exchanger as recited in  claim 13 , in which the second set of fluid channels is interspersed throughout the first set of fluid channels, providing flow through the second set of fluid channels that intersects the plane of the first set of fluid channels.  
   
   
       15 . The heat exchanger as recited in  claim 13 , in which the second set of fluid channels provides fluid flow substantially parallel to the normal of the single plane of the first set of fluid channels.  
   
   
       16 . The heat exchanger as recited in  claim 15 , in which the first set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       17 . The heat exchanger as recited in  claim 16 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       18 . The heat exchanger as recited in  claim 17 , in which the individual channels of both the first and second set of fluid channels have a smallest cross sectional dimension less than 1.0 mm.  
   
   
       19 . The heat exchanger as recited in  claim 17 , in which the individual channels of both the first and second set of fluid channels have a smallest cross sectional dimension less than 0.50 mm.  
   
   
       20 . The heat exchanger as recited in  claim 1 , in which the first set of fluid channels and the second set of fluid channels are contained in a unitary body panel which separates the sets of fluid channels with walls.  
   
   
       21 . The heat exchanger as recited in  claim 20 , in which the wall thickness between the first set of fluid channels and the second set of fluid channels is less than 0.250 mm.  
   
   
       22 . The heat exchanger as recited in  claim 20 , in which the wall thickness between the first set of fluid channels and the second set of fluid channels is less than 0.100 mm.  
   
   
       23 . The heat exchanger as recited in  claim 18 , in which the first set of fluid channels and the second set of fluid channels are contained in a unitary body panel which separates the sets of fluid channels with walls.  
   
   
       24 . The heat exchanger as recited in  claim 23 , in which the wall thickness between the first set of fluid channels and the second set of fluid channels is less than 0.250 mm.  
   
   
       25 . The heat exchanger as recited in  claim 23 , in which the wall thickness between the first set of fluid channels and the second set of fluid channels is less than 0.100 mm.  
   
   
       26 . A heat exchanger that transfers heat between two fluids, comprising: 
 a. A first set of fluid channels, arrayed substantially in a plane, which directs the first fluid flow;    b. A second set of fluid channels, interspersed throughout the plane of the first set of fluid channels, which directs the second fluid flow to intersect the plane of the first fluid channels, and in which the second set of fluid channels is made up of individual channels with hydraulic diameter of less than 1.0 mm, and in which the individual channels of the second set of fluid channels each have a ratio of flow length to hydraulic diameter less than one half of the same ratio in the individual channels of the first set of fluid channels.    
   
   
       27 . The heat exchanger as recited in  claim 26 , in which each channel of the second set of fluid channels has a flow length less than 8.0 mm.  
   
   
       28 . The heat exchanger as recited in  claim 26 , in which each channel of the second set of fluid channels has a flow length less than 4.0 mm.  
   
   
       29 . The heat exchanger as recited in  claim 26 , in which each channel of the second set of fluid channels has a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       30 . The heat exchanger as recited in  claim 27 , in which each channel of the second set of fluid channels has a hydraulic diameter less than 2.0 mm.  
   
   
       31 . The heat exchanger as recited in  claim 26 , in which the second set of fluid channels in comprised of individual channels with substantially rectangular cross section.  
   
   
       32 . The heat exchanger as recited in  claim 30 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       33 . The heat exchanger as recited in  claim 31 , in which the cross-sectional area of each channel of the second set of fluid channels has a longest dimension substantially parallel to the direction of the first fluid flow.  
   
   
       34 . The heat exchanger as recited in  claim 31 , in which the rectangular cross section of each channel of the second set of fluid channels has a smallest dimension between 0.125 mm and 1.0 mm.  
   
   
       35 . The heat exchanger as recited in  claim 35 , in which the cross-sectional area of each channel of the second set of fluid channels has a longest dimension substantially parallel to the direction of the first fluid flow.  
   
   
       36 . The heat exchanger as recited in  claim 35 , in which the rectangular cross section of each channel of the second set of fluid channels has a smallest dimension less than 1.0 mm.  
   
   
       37 . The heat exchanger as recited in  claim 26 , in which the first set of fluid channels consists of individual channels with substantially rectangular cross section, intermittently connected to adjacent channels.  
   
   
       38 . The heat exchanger as recited in  claim 37 , in which the cross-sectional area of each channel of the first set of fluid channels has a longest dimension substantially parallel to the direction of the second fluid flow.  
   
   
       39 . The heat exchanger as recited in  claim 38 , in which each channel of the second set of fluid channels has a flow length less than 8.0 mm.  
   
   
       40 . The heat exchanger as recited in  claim 39 , in which each channel of the second set of fluid channels has a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       41 . The heat exchanger as recited in  claim 40 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       42 . The heat exchanger as recited in  claim 26 , in which the first set of fluid channels and the second set of fluid channels are comprised by a unitary body flat panel, which separates the sets of fluid channels with walls.  
   
   
       43 . The heat exchanger as recited in  claim 42 , in which the walls are no thicker than 0.250 mm.  
   
   
       44 . The heat exchanger as recited in  claim 26 , in which the individual channels of the second set of fluid channels each have a ratio of flow length to hydraulic diameter less than one fifth of the same ratio in the individual channels of the first set of fluid channels.  
   
   
       45 . The heat exchanger as recited in  claim 44 , in which the first set of fluid channels and the second set of fluid channels are comprised by a unitary body flat panel, which separates the sets of fluid channels with walls.  
   
   
       46 . The heat exchanger as recited in  claim 45 , in which the walls are no thicker than 0.250 mm.  
   
   
       47 . The heat exchanger of  claim 26 , in which the individual channels of the second set of fluid channels each have a ratio of flow length to hydraulic diameter less than one tenth of the same ratio in the individual channels of the first set of fluid channels.  
   
   
       48 . The heat exchanger as recited in  claim 47 , in which the first set of fluid channels and the second set of fluid channels are comprised by a unitary body flat panel, which separates the sets of fluid channels with walls.  
   
   
       49 . The heat exchanger as recited in  claim 48 , in which the walls are no thicker than 0.250 mm.  
   
   
       50 . A primary surface heat exchanger that transfers heat between two fluids, comprising: 
 a. A first set of fluid channels, arrayed substantially in a plane, which directs a first fluid flow and in which the hydraulic diameter of the individual first fluid channels is less than 1.0 mm;    b. A second set of fluid channels which directs a second fluid flow so that it intersects the plane of the first fluid channels and in which the hydraulic diameter of the individual second fluid channels is less than 1.0 mm; and which provides an open area to the second fluid of more than 25%.    
   
   
       51 . The heat exchanger as recited in  claim 50 , in which the first set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       52 . The heat exchanger as recited in  claim 50 , in which each channel in the first set of fluid channels has a hydraulic diameter between 0.250 mm and 1.0 mm.  
   
   
       53 . The heat exchanger as recited in  claim 50 , in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       54 . The heat exchanger as recited in  claim 50 , in which each channel in the second set of fluid channels has a hydraulic diameter between 0.250 and 1.0 mm.  
   
   
       55 . The heat exchanger as recited in  claim 50 , in which the first set of fluid channels is comprised of individual channels with substantially rectangular cross section, and in which the second set of fluid channels is comprised of individual channels with substantially rectangular cross section.  
   
   
       56 . The heat exchanger as recited in  claim 55 , in which the individual channels in the first set of fluid channels each have a hydraulic diameter between 0.250 and 1.0 mm, and in which the individual channels in the second set of fluid channels each have a hydraulic diameter between 0.250 and 1.0 mm.  
   
   
       57 . The heat exchanger as recited in  claim 50 , in which the second set of fluid channels is comprised of individual channels with a flow length less than 8.0 mm.  
   
   
       58 . The heat exchanger as recited in  claim 50 , in which the second set of fluid channels is comprised of individual channels with a flow length less than 4.0 mm.  
   
   
       59 . The heat exchanger as recited in  claim 56 , in which the individual channels in the second set of fluid channels each have a flow length less than 8.0 mm.  
   
   
       60 . The heat exchanger as recited in  claim 56 , in which the individual channels in the second set of fluid channels each have a flow length less than 4.0 mm.  
   
   
       61 . The heat exchanger as recited in  claim 50 , wherein the second set of fluid channels provides an open area to the second fluid between 25% and 50%.  
   
   
       62 . The heat exchanger as recited in  claim 50 , wherein the second set of fluid channels provides an open area to the second fluid between 30% and 45%.  
   
   
       63 . The heat exchanger as recited in  claim 59 , wherein the second set of fluid channels provides an open area to the second fluid between 25% and 50%.  
   
   
       64 . The heat exchanger as recited in  claim 59 , wherein the second set of fluid channels provides an open area to the second fluid between 30% and 45%.  
   
   
       65 . A primary surface heat exchanger for transferring heat between a first fluid and a second fluid, comprising: 
 a. A first set of fluid channels, arrayed substantially in a plane, which directs the first fluid flow; and    b. A second set of fluid channels, interspersed throughout the plane of the first set of fluid channels, which directs the second fluid flow to intersect the plane of the first fluid channels; and in which each channel of the second set of fluid channels has a value of length to hydraulic diameter which is less than the ratio of length to hydraulic diameter of each channel of the first set; and in which each channel of the second set of fluid channels has both a flow length of less than 8.0 mm, and a value of said flow length divided by the square of the channel's hydraulic diameter between 5 mm −1  and 30 mm −1 .    
   
   
       66 . The heat exchanger as recited in  claim 65 , in which each channel of the second set of fluid channels has a flow length less than 4.0 mm.  
   
   
       67 . The heat exchanger as recited in  claim 65 , in which each channel in the first set of fluid channels has a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       68 . The heat exchanger as recited in  claim 65 , in which each channel in the second set of fluid channels has a hydraulic diameter between 0.250 mm and 2.0 mm.  
   
   
       69 . The heat exchanger as recited in  claim 65 , in which the second set of fluid channels comprises individual channels with substantially rectangular cross section.  
   
   
       70 . The heat exchanger as recited in  claim 69 , in which each channel in the second set of fluid channels has a cross sectional dimension substantially parallel to the direction of fluid flow in the first set of channels.  
   
   
       71 . The heat exchanger as recited in  claim 69 , in which each channel in the second set of fluid channels has a smallest cross sectional dimension measuring between 0.125 mm and 1.0 mm.  
   
   
       72 . The heat exchanger as recited in  claim 68 , in which the second set of fluid channels consists of individual channels with substantially rectangular cross section.  
   
   
       73 . The heat exchanger as recited in  claim 72 , in which each channel in the second set of fluid channels has a smallest cross sectional dimension measuring between 0.250 mm and 0.50 mm.  
   
   
       74 . The heat exchanger as recited in  claim 65 , in which the first set of fluid channels consists of individual channels with substantially rectangular cross section.  
   
   
       75 . The heat exchanger as recited in  claim 74 , in which each channel in the first set of fluid channels has a cross sectional dimension substantially parallel to the direction of fluid flow through the second set of fluid channels.  
   
   
       76 . The heat exchanger as recited in  claim 73 , in which the first set of fluid channels consists of individual channels with substantially rectangular cross section.  
   
   
       77 . The heat exchanger as recited in  claim 76 , in which the cross section of each channel in the first set of fluid channels has a longest side substantially parallel to the direction of fluid flow through the second set of fluid channels.  
   
   
       78 . The heat exchanger as recited in  claim 77 , in which each channel in the first set of fluid channels has a smallest cross sectional dimension measuring between 0.250 mm and 0.50 mm.  
   
   
       79 . The heat exchanger as recited in  claim 65 , in which the first set of fluid channels and the second set of fluid channels are comprised by a unitary body flat panel and separated from one another by walls.  
   
   
       80 . The heat exchanger as recited in  claim 79 , in which the walls have a thickness less than 0.250 mm.  
   
   
       81 . The heat exchanger as recited in  claim 78 , in which the first set of fluid channels and the second set of fluid channels are contained in a unitary body flat panel and separated from one another by walls.  
   
   
       82 . The heat exchangers as recited in  claim 81 , in which the walls have a thickness less than 0.250 mm.  
   
   
       83 . The heat exchanger as recited in  claim 65 , in which each channel in the second set of fluid channels has a value of flow length divided by hydraulic diameter less than one half of the ratio of flow length divided by hydraulic diameter provided by each channel in the first set of fluid channels.  
   
   
       84 . The heat exchanger as recited in  claim 65 , in which each channel in the second set of fluid channels has a value of flow length divided by hydraulic diameter less than one fifth the ratio of flow length divided by hydraulic diameter provided by each channel in the first set of fluid channels.  
   
   
       85 . The heat exchanger as recited in  claim 82 , in which each channel in the second set of fluid channels has a value of flow length divided by hydraulic diameter less than one half of the ratio of flow length divided by hydraulic diameter provided by each channel in the first set of fluid channels.  
   
   
       86 . The heat exchanger as recited in  claim 82 , in which each channel in the second set of fluid channels has a value of length divided by hydraulic diameter less than one fifth of the ratio of flow length divided by hydraulic diameter provided by the first set of fluid channels.  
   
   
       87 . A primary surface heat exchanger for transferring heat between a first fluid and a second fluid, comprising: 
 a. A network of fluid channels consisting of substantially parallel channels defining a primary direction of flow for the first fluid, in which said channels are intermittently connected to one another by channels allowing secondary flow substantially perpendicular to the primary direction of the first fluid; and    b. A set of fluid channels, arrayed throughout the network of fluid channels, which directs the second fluid flow to intersect with the plane defined by the primary and secondary flow through the network; and in which each channel of the second set of fluid channels has both a flow length of less than 8.0 mm and a nominal hydraulic diameter less than 2.0 mm.    c. A plurality of walls separating the set of fluid channels from the network, each wall providing a potential conduit of heat transfer between the first fluid and the second fluid.    
   
   
       88 . The heat exchanger as recited in  claim 87 , wherein the set of fluid channels provides an open area to the second fluid between 25% and 50%.  
   
   
       89 . The heat exchanger as recited in  claim 87 , wherein the set of fluid channels provides an open area to the second fluid between 30% and 45%.  
   
   
       90 . The heat exchanger as recited in  claim 87 , wherein the set of fluid channels is comprised of individual channels with a substantially rectangular cross section.  
   
   
       91 . The heat exchanger as recited in  claim 88 , wherein the set of fluid channels is comprised of individual channels with a substantially rectangular cross section.  
   
   
       92 . The heat exchanger as recited in  claim 87 , in which the set of fluid channels directs the second fluid flow to be substantially parallel to the normal of the first fluid flow through the network of fluid channels.  
   
   
       93 . The heat exchanger as recited in  claim 92 , in which the set of fluid channels provides an open area to the second fluid between 25% and 50%.  
   
   
       94 . The heat exchanger as recited in  claim 92 , in which the set of fluid channels provides an open area to the second fluid between 30% and 45%.  
   
   
       95 . The heat exchanger as recited in  claim 94 , in which the set of fluid channels is comprised of individual channels with a substantially rectangular cross section.