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.

Description

FIELD OF THE INVENTION

The invention relates to a dual stage water heater assembly which combines the advantages of a tankless water heater and a more traditional tank-type water heater.

BACKGROUND OF THE INVENTION

Tankless inline water heaters are designed to heat a continuous supply of water on demand of the user. They accomplish this in several different ways. In the most common embodiment, the water travels a circuitous route past a heating element or elements, which heat the water to a desired temperature. Tankless inline water heaters are more fuel efficient than traditional tank water heaters. One disadvantage of this type of system, however, is that in many cases it cannot keep up with demand, with the result that water of an undesirably low temperature is encountered. The size of the heating element or elements in a tankless water heater limits the amount of hot water that can be provided at one time. Without a large heating element, a tankless water heater can only provide hot water to one or two users. In addition, the heating element or elements in a tankless water heater only begin heating the water when the hot water is demanded. In a tankless water heater, small demands, unintended to call for hot water, can activate the heating element or elements unless a delay mechanism is used. Use of a delay mechanism, however, substantially lengthens the response time when hot water is actually desired. During cold weather, cooler water entering a tankless water heater may not be heated quickly enough or hot enough for the intended use, resulting in a cold shower or other such inconvenience.

Traditional tank-type water heaters are able to provide water on demand, as hot as the user may desire. But, in order to provide hot water on demand, a large amount of energy must be used to heat and maintain the water in the tank at a desired temperature. A tank water heater also is limited in the amount of hot water it can supply. If a number of users desire hot water at the same time, a tank water heater may quickly run out of its available supply of hot water, unless a larger tank, requiring more energy, is utilized.

SUMMARY OF THE INVENTION

To solve the problems with existing inline tankless water heaters and traditional tank-type water heaters, I have designed an improved two stage water heater assembly. The invention comprises a tankless inline water heater stage and a traditional tank-type water heater stage in a way that provides the user with unlimited hot water on demand and with energy savings because a much smaller tank can be used with the tank water heater stage.

Water is heated in the tankless stage and enters the tank stage at a temperature at or near the temperature selected by the user. As a result, the tank is smaller and requires less energy to maintain the water at a desired temperature. Consequently, a virtually unlimited supply of water can be provided at a desired high temperature by using a modest amount of energy and smaller tank in the tank stage.

In addition, the present invention can be easily retrofitted into an existing home because it takes up about the same amount of space as a traditional tank-type water heater. Because installation of the present invention does not require extensive modification of an existing home, it is much less expensive to install than existing two stage water heaters. As such, the present invention provides an inexpensive means for increasing energy savings by reducing the amount of energy that is needed to heat water in a residential or commercial setting.

In one aspect of this invention, it provides a hot water heater assembly wherein the desirable features of tankless inline water heater are combined with the desirable features of a traditional tank-type water heater, commonly used in the United Sates.

In another aspect of this invention, it provides an improved hot water heater assembly, which provides an unlimited supply of hot water on demand while using less energy and can be installed inexpensively in an existing home.

To the accomplishment of the above and related aspects, the invention may be embodied in the form illustrated in the accompanying drawings. The drawings, however, are illustrative only. Variations are contemplated as being part of the invention, limited only by the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the apparatus of the invention.

FIG. 2 is a perspective view of the apparatus of the invention.

FIG. 3 is a top view of the tankless stage of the apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a two stage water heater assembly 1, comprising a tankless stage 2 and a storage stage 3. Water 4 enters the tankless stage through cold water inlet 5. The water 4 circulates through entrance chamber 6 through coiled tubing 7 and is heated by a first heating means 8. In FIG. 1, a natural gas burner is used as the heating means although the heating means could also include a propane burner, a heating oil burner or electric heating elements. Heating means 8 is connected to control valve 9. Exhaust gas from heating means 8 is vented to the atmosphere through exhaust flue 24. After being heated by heating means 8, pre-heated water 14 exits tankless stage 2 through hot water outlet 10. Pre-heated water 14 then enters storage stage 3 through hot water inlet port 11, which is connected to flow control valve 12. Pre-heated water 14 is stored in water storage tank 13 until it is desired for use. Pre-heated water 14 is maintained at a desired temperature by second heating means 15, which is located beneath lower wall 17 and connected to control valve 16. Exhaust from heating means 15 is vented to the atmosphere through exhaust flue 18. Heated water 19 exits storage stage 3 for use by the user through hot water outlet 20, which is activated by hot water flow control valve 21. Temperature sensing means 22 and tank water level sensing means 23 are located within storage tank 13. Temperature sensing means 22 is connected to control valve 16, which activates heating means 15 when temperature sensing means 22 indicates that the temperature of pre-heated water 14 in storage tank 13 is below a temperature selected by the user. Tank water level sensing means 23 is connected to flow control valve 12, which activates hot water inlet port 11 when tank water level sensing means 23 indicates that pre-heated water 14 has dropped below a certain level within storage tank 13. Flow control valve 12 is connected to control valve 9. When flow control valve 12 activates hot water inlet port 11, it also sends a signal to control valve 9, which in turn activates heating means 8, which heats water 4 flowing through coiled tubing 7.

When the user desires hot water and turns on a hot water tap, control valve 21 is activated and opens hot water outlet 20 permitting hot water 19 to flow through pipes to the user. This will result in a drop in the water level within storage tank 13 causing tank water level sensing means 23 to send a signal to flow control valve 12, which then permits pre-heated water 14 to enter storage tank 13 through hot water inlet port 11.

The assembly is approximately the same size as traditional tank-type water heater, which is predominantly used in the U.S., so it can easily fit into the space that was previously occupied by a traditional tank-type water heater. Thus, it provides a cheaper, more efficient, more reliable option to either an inline tankless water heater or a traditional tank-type water heater.

The description of the invention above should not be interpreted as limiting the invention to the disclosed embodiment because those who are skilled in the art to which the invention relates will be able to devise other equivalent forms thereof within the scope of the invention. Variations and changes, which are obvious to one skilled in the art, are intended to be within the scope and nature of the present invention.

Claims

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.