| abstract |
A storage fluid heater for heating a fluid, employs a heat storage unit, a heating element thermally coupled to the heat storage unit, and a heat recovery tube thermally coupled to the heat storage unit. The recovery tube is made from a material having a coefficient of thermal expansion so that as the average temperature of the heat storage unit near the heat recovery tube increases, the surface area of gaps between the heat recovery tube and the storage unit increases, causing the contact resistance between the heat storage unit and the heat recovery tube to increase. The temperature of the fluid flowing within the heat recovery tube is thereby limited to a predetermined maximum. A structure that relieves excess pressure when the flow of fluid through the tube is stopped has an expansion tank connected to the fluid inlet of the tube. |