Air cycle condenser cold inlet heating using internally finned hot bars

Abstract

An environmental control system (ECS) includes an air cycle machine with an expansion turbine and a condenser having a cold air inlet connected to receive air from the expansion turbine. The condenser has hollow, internally finned hot bars positioned at the cold air inlet to prevent ice formation at the cold air inlet.

1 . An environmental control system (ECS) comprising:
 an air cycle machine with an expansion turbine; and   a condenser having a cold air inlet connected to receive air from the expansion turbine,   the condenser having hollow, internally finned hot bars positioned at the cold air inlet.   
     
     
         2 . The ECS of  claim 1  wherein the condenser is a plate-fin condenser. 
     
     
         3 . The ECS of  claim 1  wherein the hot bars are positioned transversely across the cold air inlet. 
     
     
         4 . The ECS of  claim 1  wherein the hot bars are connected to a bleed-air plenum. 
     
     
         5 . The ECS of  claim 4  further comprising a bleed air inlet connected to the plenum. 
     
     
         6 . The ECS of  claim 5  further comprising a flow regulator connected to the bleed air inlet. 
     
     
         7 . A condenser for an aircraft ECS comprising:
 a plate-fin core having a cold-inlet side; and   hollow internally finned hot bars disposed transversely across the cold-inlet side of the core.   
     
     
         8 . The condenser of  claim 7  further comprising:
 layers of cold fins, 
 the hot bars having rounded leading surface elements, 
 the hot bars being attached to the cold fins at the cold-inlet side so that the rounded leading surface elements project outwardly from the cold fins. 
 
     
     
         9 . The condenser of  claim 7  wherein the hot bars are aluminum extrusions. 
     
     
         10 . The condenser of  claim 7  further comprising a bleed-air plenum connected to the hot bars. 
     
     
         11 . The condenser of  claim 10  wherein the bleed-air plenum is bounded by a divider bar attached to the condenser and a frame member of the condenser. 
     
     
         12 . The condenser of  claim 7  wherein the hot bar comprises:
 outer-surface elements surrounding a passageway; 
 fins attached to one or more of the outer-surface elements and projecting into the passageway. 
 
     
     
         13 . The condenser of  claim 12  wherein the fins are attached to opposed lateral surface elements and the fins extend along an entire length of the hot bar. 
     
     
         14 . The condenser of  claim 12  wherein the passageway has front-to-back width of about 0.25 inch and a height of about 0.15 inch. 
     
     
         15 . The condenser of  claim 12  wherein the fin has a length of about 0.045 inch and a thickness of about 0.030 inch. 
     
     
         16 . The condenser of  claim 12  wherein:
 a first set of two of the fins projects from a first one of the lateral surface elements; 
 a second set of two of the fins projects from a second one of the lateral surface elements: and 
 the fins of the first set do not touch the fins of the second set. 
 
     
     
         17 . A method for conditioning air for delivery to an aircraft cabin comprising the steps of:
 passing the air through an expansion turbine to cool the air;   heating the air by passing the air over hollow internally finned hot bars attached to a cold-inlet side of a condenser;   passing the air into a cold-inlet side of a condenser; and   passing the air into the cabin.   
     
     
         18 . The method of  claim 17  further comprising passing heated gas into and through the hot bars to heat the hot bars. 
     
     
         19 . The method of  claim 17  further comprising the step of maintaining temperature of a leading outer surface element of the hot bars at a temperature above a freezing point of water. 
     
     
         20 . The method of  claim 19  wherein the step of maintaining temperature of the leading outer surface comprises transferring heat from bleed of an engine of the aircraft into internal fins within a hollow passageway of the hot bar.