Patent ID: 8104532

Claim:
A shower heat exchanger system comprising: a tub/shower stall with a single drain for draining grey waste water; a shower in said tub/shower stall having a shower head, sources of incoming cold and hot water including cold and hot water valves with handles, respectively; a mixing area for the incoming cold and hot water prior to delivery to said shower head; a heat exchange system for preheating incoming cold water to said cold water valve located below said tub/shower stall; said heat exchange system comprising a housing containing a flat plate of thermally conductive material having a gray water chamber above said flat plate within said housing, and an incoming cold water chamber below said flat plate within said housing; said gray water chamber having an inlet through a top wall of said housing at one end adjacent said drain for receiving said gray water being discharged through said drain, and having an outlet through a wall of said housing at an opposite end of said gray water chamber discharging the gray water directly into a sewer system, said gray water spreading over a complete width and length of said flat plate in a straight and uninterrupted flow path as said gray water moves from said inlet to said outlet of said gray water chamber, said heat exchange system being a dry base structure thereby avoiding any leaking gray water from intruding into potable water; said gray water chamber inlet, the height throughout said gray water chamber, and said gray water outlet being sufficiently large as to accommodate a ball of about two inches in diameter to accommodate a snaking cable to remove any clog, in accordance with requirements of the Uniform Plumbing Code; said gray water chamber having means for guiding said snaking cable into the outlet of said gray water chamber to facilitate any removal of a clog; said incoming cold water chamber having an inlet adjacent the outlet of said gray water chamber and an outlet adjacent the inlet of said gray water chamber so that flows in both chambers are countercurrent to each other; said incoming cold water chamber having a serpentine flow pattern and being insulated from below; whereby heat is transferred from the grey waste water spreading over said flat plate to preheat the incoming cold water flowing underneath said flat plate in contact with a bottom surface of said flat plate; said cold water valve directing flow of said preheated incoming cold water from said incoming cold water chamber to said mixing area so that hot water from a water heater is mixed with said preheated incoming cold water in said mixing area as a substitute for the incoming cold water that would be normally plumbed to the discharge shower head, thereby reducing the amount of hot water flow required to achieve the desired showering temperature.