Indirect heat exchange device and method of exchanging heat

Abstract

Indirect heat exchange device comprising heat exchanger tubes arranged in at least 2 layers each of which layers comprises at least 2 heat exchanger tubes wherein the heat exchanger tubes are eccentrically finned ( 53 ) heat exchanger tubes having a ratio of surface area of the fins to surface area of the tube of at least 5, and in which device the heat exchanger tubes have similar eccentricity; and method of exchanging heat with the help of such device.

1 . Indirect heat exchange device comprising heat exchanger tubes arranged in at least 2 layers each of which layers comprises at least 2 heat exchanger tubes wherein the heat exchanger tubes are eccentrically finned heat exchanger tubes having a ratio of surface area of the fins to surface area of the tube of at least 5, and in which device the heat exchanger tubes have similar eccentricity. 
     
     
         2 . Indirect heat exchange device according to  claim 1 , wherein the ratio of surface area of the fins to surface area of the tube is at least 7. 
     
     
         3 . Indirect heat exchange device according to  claim 2 , wherein the direction of the eccentricity is parallel to the direction in which fluid outside the tube normally flows. 
     
     
         4 . Indirect heat exchange device according to  claim 3  further comprising a fan having a blow or suck direction across the heat exchanger tubes and defining an upstream side of the heat exchanger tubes, wherein the geometric centroid of the cross-section of the envelope defined by the fins of the heat exchanger tubes is arranged upstream from the axis of the tubes. 
     
     
         5 . The indirect heat exchange device according to  claim 3  arranged in a heater having flow direction of heating fluid across the heat exchanger tubes and defining a downstream side of the heat exchanger tubes, wherein the geometric centroid of the cross-section of the envelope defined by the fins is arranged downstream from the axis of the tubes. 
     
     
         6 . A method of exchanging heat between a first fluid and a second fluid, the method comprising:
 providing a indirect heat exchange device according to any one of  claim 1 ;   passing first fluid through the heat exchanger tubes of the device; and   passing second fluid along a flow direction across the indirect heat exchange device, wherein the eccentricity of the heat exchanger tubes is parallel to the flow direction of second fluid.   
     
     
         7 . The method according to  claim 6 , wherein the first fluid is a cooling fluid, in particular air, and wherein the geometric centroid of the fins of each of the heat exchanger tubes is arranged upstream from the axis of the tubes. 
     
     
         8 . The method according to  claim 6 , wherein the first fluid is a heating fluid, in particular comprising combustion products, and wherein the geometric centroid of the fins of each of the heat exchanger tubes is arranged downstream from the axis of the tubes. 
     
     
         9 . The method according to  claim 8 , wherein the upstream and downstream differential temperatures at the tip of the fins of the heat exchanger tubes are substantially equal.