Two-stage water heater assembly

Abstract

A two stage water heater assembly comprising a tankless stage, which preheats water, and water storage tank stage, which stores the preheated water and maintains the water at a desire temperature. This water heater assembly provides the user with an unlimited supply of hot water on demand while doing so in a more energy efficient manner than either an inline tankless water heater or a traditional tank-type water heater.

1 . A two-stage water heater assembly comprising:
 a tankless stage comprising an entrance chamber with an elongated, coiled tube located within said entrance chamber, said tube connected in fluid receiving relation to a cold water inlet and located above first heating means, said first heating means are adapted for heating water that flows through said tube, said water being allowed to exit the tankless stage through a hot water outlet;   a storage stage comprising an upright thermally insulated cylindrical water storage tank with a hot water inlet port connected in fluid receiving relation to the hot water outlet of said tankless stage and attached to a flow control valve, second heating means for heating the water within the storage tank, temperature sensing means for said water storage tank, said temperature sensing means producing a signal indicative of the water temperature in said water storage tank, tank water level sensing means, said tank water level sensing means producing a signal indicative of the water level in said water storage tank, said water being allowed to exit the storage stage through a second hot water outlet; and   control means connected to said flow control valve and responsive to the signals produced by said tank water level sensing means to maintain the water stored in the water storage tank at a certain level by activating the hot water inlet port only if the tank water level sensing means indicate that the water is below the required water level; and   control means connected to said second heating means and responsive to the signals produced by said temperature sensing means to maintain the water stored in the water storage tank and released through said second hot water outlet at a desired temperature by activating the heating element in the storage stage only if the water temperature sensing means indicate that the water is below the desired outlet temperature as selected by an outlet temperature selecting means.   
   
   
       2 . The two stage water heater assembly of  claim 1  wherein the heating means is electrical. 
   
   
       3 . The two stage water heater assembly of  claim 1  wherein the heating means is natural gas.