Hot water recovery

Abstract

The concepts relate to reducing energy loss associated with hot water systems. One example is manifest as a selective hot water isolation device that is configured to be connected in fluid flowing relation with a first water line and a second water line and where the selective hot water isolation device is configured to control water cross-over from the second water line into the first water line based upon water flow through the first water line.

1 . A selective hot water isolation device that is configured to be connected in fluid flowing relation with a hot water line and a cold water line and where the selective hot water isolation device is configured to control cold water cross-over from the cold water line into the hot water line based upon water flow through the hot water line. 
     
     
         2 . The selective hot water isolation device of  claim 1 , wherein the selective hot water isolation device is further configured to allow the cold water cross-over for a window of time after water flow through the first water line stops. 
     
     
         3 . The selective hot water isolation device of  claim 2 , wherein the window of time starts immediately after water flow through the hot water line stops or wherein the window of time starts after a delay period. 
     
     
         4 . The selective hot water isolation device of  claim 1 , wherein the selective hot water isolation device is configured to function as a valve such that the cold water cross-over occurs subsequent to the water flow through the hot water line. 
     
     
         5 . The selective hot water isolation device of  claim 1 , wherein the selective hot water isolation device is configured to function as a delay valve such that the cold water cross-over is delayed by a defined duration after cessation of the water flow through the hot water line. 
     
     
         6 . The selective hot water isolation device of  claim 5 , wherein the defined duration is defined, at least in part, by a relationship between a volume of the selective hot water isolation device and a dimension of a bleed hole within the selective hot water isolation device. 
     
     
         7 . A cross-over device that is configured to be connected in fluid flowing relation with a hot water line and a cold water line and where the cross-over device is configured to allow cold water to flow from the cold water line to the hot water line.