Field of the Invention

The present invention related to a water heater and a method of operating same. The invention has been primarily developed to be used with a domestic water heater with an internal electric heating element and associated solar panel and will be described hereinafter with reference to this application.

However, the invention is not limited to this particular application and is also suitable for hot water systems using gas burners and without associated solar panels.

Background of the Invention

The tank of a water heater is a pressure vessel and, for safety, is required by the regulatory authorities of many countries to have a pressure temperature relief (PTR) valve which bleeds (i.e. releases) water from the interior of the tank when predetermined pressure or temperature conditions within the tank are exceeded. However, it is estimated that during the course of a single day approximately 10% of the volume of a water heater tank is released through the PTR valve, which hitherto drains to waste. In the case of a tank having a 250 litre volume, this equates to water wastage of about 25 litres per day which is a significant environmental loss.

Further, many water heaters have one or more associated solar panels as an energy saving measure. When enough solar energy is available, such heaters utilise the solar panels in heating the water in the tank in preference to the tank's gas or electric heating element. Some solar panels incorporate a drain line and associated valving which, when the ambient temperature falls below a predetermined level, drains the water from the solar panel so that it does not freeze in the solar panel and cause damage. The water drained from solar panels also hitherto drains to waste and is thus also an environmental loss.

Object of the Invention

It is an object of the present invention to substantially overcome or at least ameliorate the water wastage described above. Summary of the Invention

Accordingly, in a first aspect, the present invention provides a water heater including:

a tank;

a pressure temperature relief (PTR) valve adapted to release water from the tank when predetermined pressure or temperature conditions in the tank are exceeded, the PTR valve having an outlet; and

a reservoir, open to atmosphere, having an inlet, in gravity fed fluid communication with the PTR valve outlet, and an outlet.

In a second aspect, the present invention provides a water heater including: a tank;

a solar panel with a drain line adapted to release water from the solar panel when predetermined temperature conditions in the solar panel are exceeded, the drain line valve having an outlet; and

a reservoir, open to atmosphere, having an inlet, in gravity fed fluid communication with the drain line outlet, and an outlet.

In a third aspect, the present invention provides a water heater including:

a tank;

a pressure temperature relief (PTR) valve adapted to release water from the tank when predetermined pressure or temperature conditions in the tank are exceeded, the PTR valve having an outlet;

a solar panel with a drain line adapted to release water from the solar panel when predetermined temperature conditions in the solar panel are exceeded, the drain line valve haying an outlet; and

a reservoir, open to atmosphere, having an inlet, in gravity fed fluid communication with the PTR valve outlet and the drain line outlet, and an outlet.

The reservoir is preferably mounted to the exterior of the tank. The reservoir preferably has a volume of about 25 litres.

The reservoir is preferably mounted at a height that positions the reservoir outlet high enough for gravity fed flow to other locations.

The reservoir outlet is preferably in fluid communication with a toilet cistern. The reservoir outlet is preferably in fluid communication with a garden outlet. The reservoir outlet is preferably in fluid communication with a washing machine.

In a fourth aspect, the present invention provides a method of operating a water heater, the method including the steps of: releasing water from a tank via a pressure temperature relief (PTR) valve when predetermined pressure or temperature conditions in the tank are exceeded;

directing, via gravity, the released water to a reservoir, open to atmosphere, associated with the tank.

In a fifth aspect, the present invention provides a method of operating a water heater, the method including the steps of:

releasing water from a solar panel via a drain line when predetermined temperature conditions in the solar panel are exceeded; and

directing, via gravity, the released water to a reservoir, open to atmosphere, associated with the solar panel.

In a sixth aspect, the present invention provides a method of operating a water heater, the method including the steps of:

releasing water from a tank via a pressure temperature relief (PTR) valve when predetermined pressure or temperature conditions in the tank are exceeded;

releasing wateT from a solar panel via a drain line when predetermined temperature conditions in the solar panel are exceeded; and

directing, via gravity, the released water from the tank and/or the solar panel to a reservoir, open to atmosphere, associated with the tank. Brief Description of the Drawings

A preferred embodiment of the invention will now be described, by way of an example only, with reference to the accompanying drawing in which:

Fig. 1 is a perspective view of an embodiment of a water heater. Detailed Description of the Preferred Embodiments

Fig. 1 shows an embodiment of a domestic water heater 10 of 250 litre capacity. The water heater 10 has an insulated casing 12 within which is provided a water tank. A PTR valve 1 is connected to the water tank. The water heater 10 also has an associated solar panel 16 with a drain line 18. The water heater 10 also includes a cabinet 20 within which is housed power and control componentry. '

A reservoir 22 of approximately 25 litres in volume is mounted above the cabinet 20. For aesthetic considerations, the reservoir 22 has a shape substantially common to that of the cabinet 20. The reservoir 20 has an inlet in the form of an opening 24 in its upper surface, which is open to atmosphere. Put another way, the reservoir 20 is not pressurised. The reservoir 22 also has an outlet 26. A PTR valve has an outlet pipe 28 which is in fluid communication, via gravity, with the reservoir opening 24. The drain line 18 also has an outlet pipe 30 which is similarly in gravity fed fluid communication with the inlet 24 of the reservoir 22.

A more detailed description of the solar panel draining process can be found in the Applicant's International PCT Patent Application No. PCT/AU2008/001476, the contents of which are incorporated herein by cross-reference.

The water heater 10 also includes a mains water inlet 32 and a heated water outlet 34.

The operation of the water heater 10 will now be described. Upon sensing that predetermined pressure or temperature conditions in the tank of the water heater 10 have been exceeded, the PTR valve 14 opens. As a result, water is released from the tank and flows through the PTR valve 14 into and through the outlet pipe 28 and, under the influence of gravity, into the reservoir 22. The water collected in the reservoir 22 can be used in numerous non-potable applications including: the flushing of toilet cisterns; the watering of gardens; and the washing of clothes in washing machines, thereby providing an environmental benefit in reducing a household's or business' overall water consumption.

Similarly, if the ambient temperature falls below a predetermined level, water is drained from the solar panel 16, via the drain line 18 which, under influence of gravity, then flows through outlet pipe 30 into the reservoir 22. This collected water can be similarly reused in non-potable applications with a similar environmental benefit as that previously described.

Although the invention has been described with reference to a preferred embodiment, it will be understood by persons skilled in the art that the invention can be embodied in many other forms.