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Method and apparatus for utilizing waste heat in hot water heaters

  • US 4,821,682 A
  • Filed: 07/24/1987
  • Issued: 04/18/1989
  • Est. Priority Date: 05/08/1986
  • Status: Expired due to Fees
First Claim
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1. In a hot water heating system having a main tank, a cold water inlet pipe connected with a supply of cold water to be heated, a fuel fired main burner for heating water in the main tank, a fuel fired pilot burner for igniting the main burner, and a flue in the main tank for discharging combustion gases, the improvement comprising:

  • a storage tank for holding water which is to be preheated prior to transfer to the main tank, said cold wate rinlet pipe discharging into said storage tank to deliver thereto incoming cold water to be heated;

    a conduit loop having an inlet end communicating with said storage tank to receive water therefrom and an outlet end communicating with said storage tank to return preheated water thereto, said conduit loop having an intermediate portion thereof extending in said flue in a generally spiral configuration to extract heat from the flue for preheating of water circulating in the conduit loop; and

    a transfer conduit extending from said storage tank to said main tank to deliver preheated water from the storage tank to the main tank to replace hot water drawn out of the main tank.

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