Drainpipe heat exchanger

Abstract

The present invention is a jacket-type heat exchanger which may, for example, be used to replace or fit over a section of drainpipe to heat fresh cold water using the waste heat in the drainwater. Normal cold water pressure is used to create an internal-expanding force on the inner thermal contact wall of the jacket, which, in turn, creates an enormous heat-transfer clamping force on the drainpipe for fast heat transfer. A longitudinal gap in the jacket (or a two-piece jacket) enables clamping movement. An external sleeve with clamps resists bulging of the outer jacket wall. The heated cold water is plumbed to a faucet or water heater so as to reduce hot water use, which, in turn, reduces energy use and related environmental damage. Double-wall construction and venting for visible leak detection satisfies plumbing code requirements. A horizontal embodiment discloses a two-piece plastic-copper drainwater heat exchanger. Use on vehicular exhaust pipes is also contemplated for providing instant interior heat and/or motor warm-up.

1 . A heat exchanger for heat transfer with a fluid within a conduit, said heat exchanger comprising:
 a chamber having a portion thereof for contacting at least a portion of said conduit, said chamber having spaced inner and outer walls defining a cavity therebetween;   a fluid inlet to said cavity for a second fluid;   a fluid outlet from said cavity for said second fluid;   attachment means exterior of said outer wall for securing said chamber to said conduit;   
     the arrangement being that said inner wall is tightened against said conduit by said attachment means. 
   
   
       2 . The heat exchanger of  claim 1  including flow directing means to direct said second fluid to flow over substantially the entire inner surface of said inner wall. 
   
   
       3 . The heat exchanger of  claim 1  where, when said second fluid is supplied under pressure said inner wall is further tightened against said conduit. 
   
   
       4 . The heat exchanger of  claim 2  wherein said portion is formed into a recess to receive at least a portion of said conduit. 
   
   
       5 . The heat exchanger of  claim 4  wherein said chamber has a substantially cylindrical configuration. 
   
   
       6 . The heat exchanger of  claim 5  wherein said portion comprises a passageway through said chamber. 
   
   
       7 . The heat exchanger of  claim 2  wherein said chamber has a C-shaped configuration. 
   
   
       8 . The heat exchanger of  claim 2  wherein said chamber has a U-shaped configuration. 
   
   
       9 . The heat exchanger of  claim 2  wherein said chamber has a bar-shaped configuration. 
   
   
       10 . The heat exchanger of  claim 7  wherein said cylindrical chamber has a gap to permit tightening of said inner wall onto said conduit. 
   
   
       11 . In a building having a plumbing system including a hot water supply, a cold water supply and a drainage pipe, the improvement comprising a heat exchanger mounted about said drainage pipe, said heat exchanger comprising:
 a chamber having a portion thereof for receiving said drainage pipe, said chamber having spaced inner and outer walls defining a cavity, a fluid inlet connected to said cavity, said fluid inlet being connected to said cold water supply;   a fluid outlet from said chamber being connected to a water fitting; and   attachment means for securing said inner wall adjacent to said drainage pipe.   
   
   
       12 . The improvement of  claim 10  wherein said chamber has fluid directing means within said chamber being arranged to direct fluid flowing from said fluid inlet to cause maximum heat transfer between fluid in said chamber and fluid flowing through said drainage pipe. 
   
   
       13 . The improvement of  claim 11  wherein said drainage pipe has a horizontal portion, said chamber being secured to said horizontal portion. 
   
   
       14 . The improvement of  claim 11  wherein said drainage pipe has a vertical portion, said chamber being secured to said vertical portion. 
   
   
       15 . The improvement of  claim 12  wherein said chamber has a substantially cylindrical configuration, said chamber having a gap therein to permit tightening said inner wall onto said drainage pipe. 
   
   
       16 . In a vehicle having an interior compartment requiring heat and an exhaust pipe through which flows hot exhaust gases, the improvement comprising a heat exchanger mounted about said exhaust pipe, said heat exchanger comprising:
 at least one chamber having a portion thereof for receiving said exhaust pipe, said chamber having spaced inner and outer walls defining a cavity, a fluid inlet to said cavity, said fluid inlet being connected to a fluid supply to be heated;   a fluid outlet from said cavity being connected to said interior compartment, and   attachment means for securing said inner wall adjacent to said exhaust pipe.   
   
   
       17 . The improvement of  claim 14  wherein said chamber has fluid directing means within said chamber arranged to maximize heat transfer between said fluid and said exhaust pipe; 
   
   
       18 . The improvement of  claim 14  wherein said chamber has a substantially cylindrical configuration, said chamber having a gap therein to permit tightening said inner wall onto said exhaust pipe.