Patent ID: 8371251

Claim:
A method of heating a fluid, comprising: providing a closed loop heat transfer system comprising: a internal combustion engine adapted to convert chemical energy into at least mechanical energy and waste heat energy; a rotary heating device operatively coupled to the engine and adapted to heat a liquid flowing there through by converting mechanical energy from the engine into thermal energy; a tank vented to the atmosphere and fluidly coupled to the rotary heating device and adapted to contain a portion the liquid in the closed loop system; a circulation pump adapted to pump the liquid through the closed loop system; a exhaust heat exchanger fluidly coupled to the tank and adapted to transfer thermal energy from a first portion of the waste heat to the liquid; a portion of a fluid-to-fluid heat exchanger fluidly coupled to the exhaust heat exchanger and to the rotary heating device; and wherein the closed loop heat transfer system is configured to operate at atmospheric pressure and to heat the liquid to less than an atmospheric boiling point of the liquid; providing an open system comprising: a third heat exchanger adapted to transfer thermal energy from another portion of the waste heat to the fluid; a second portion of the fluid-to-fluid heat exchanger fluidly coupled to the third heat exchanger; and a pump adapted to pump the fluid through the open system so that thermal energy in the closed-loop liquid is transferred across the fluid-to-fluid heat exchanger to the fluid; operating the closed loop system to heat the liquid to below its boiling point; pumping the fluid through the open system; and transferring thermal energy from the closed-loop liquid to the open system fluid, thereby heating the fluid.