AU2010200835B2

AU2010200835B2 - A Controllable Water Heater

Info

Publication number: AU2010200835B2
Application number: AU2010200835A
Authority: AU
Inventors: Brendan Vincent Bourke
Original assignee: Rheem Australia Pty Ltd
Current assignee: Rheem Australia Pty Ltd
Priority date: 2006-12-12
Filing date: 2010-03-04
Publication date: 2011-10-06
Anticipated expiration: 2027-12-11
Also published as: AU2007332141B2; AU2007332141A1; NZ583763A; WO2008070906A1; NZ577168A; AU2010200835A1

Abstract

A water heating system including a main water heater and a hot water storage container delivering heated water within a first predetermined temperature range, including the following: Water maintained in the hot water storage container at a temperature within a second pre-determined temperature range; The outlet of the main water heater connected to the outlet of the water heating system through the hot water storage container and directly through an alternative by-passing circuit, Including at least one automatically operating valve capable of directing water flow through the hot water storage container or the by-pass circuit. 1-11 1.07 0 1.050 -- 1.071 1.034,,,, 1.021 1.022 10 1.009 1.004 1.016A 1.0101.0 1.0

Description

C10029 A Method and Arrangement for Heating Water Field of the invention [001] This is a divisional patent application based on our co-pending Australian patent application AU2007332141 [002] This invention relates to a method and arrangement for heating water. [003] The invention is applicable to water heating systems where cold water can be delivered on starting of the flow of water. The invention is particularly suitable for use with instantaneous hot water systems. Background of the invention [004] A problem can occur in instantaneous water heaters, which can be heated rapidly by gas or electricity etc. Such heaters contain a heating section comprising, in the case of a gas heater, a heat exchanger, usually including a comparatively small volume of water. The heating source is only turned on when the user operates a tap to cause water to run through the heater. A flow sensor is used to detect the opening of the tap. When the tap is closed, the water flow stops and the heater is turned off. The water in the heat exchanger will cool to atmospheric temperature when the gas is turned off. Such heaters differ from storage water heaters which heat a significantly larger volume of water which is maintained within a desired temperature range by thermostatic control. Thus, the water initially delivered by the instantaneous heater will not be within the designed operating temperature range. [005] It is desirable to provide an instantaneous water heating system which reduces the volume of water delivered below a desired temperature. Summary of the invention [006] According to an embodiment of the invention, there is provided a water heating system having a system inlet and a system outlet, the system including: a first water heater having a first inlet and a first outlet; a second water heater having a second inlet and a second outlet; and a flow direction control valve; wherein the first water heater and the second water heater are connected to the flow control valve to deliver water to the system outlet either via the second outlet (being C 10029 2 the outlet of the second water heater) or directly from the first outlet (being the outlet of the first water heater). [007] According to an embodiment of the invention, there is provided a water heating system including a main water heater delivering heated water within a first predetermined temperature range and a hot water storage container, including the following: Water maintained in the hot water storage container at a temperature within a second pre-determined temperature range; The outlet of the main water heater connected to the outlet of the water heating system through the hot water storage container and directly through an alternative by-passing circuit, Including at least one automatically operating valve capable of directing water flow through the hot water storage container or the by-pass circuit. [008] The outlet of the main water heater can connect to a temperature sensitive diversion valve which directs the flow of water through the hot water storage container when the water temperature is below the first pre-determined temperature range and through the by-pass circuit when the water temperature is with-in or greater than the first pre-determined temperature range. [009] The outlet of the hot water storage container and the by-pass circuit can connect to the inlet of a temperature limiting valve which directs the flow from the hot water storage container to the system outlet when the water temperature is below the first pre-determined temperature range and the flow through the by-pass circuit when the water temperature is within or greater than the first pre-determined temperature range. [010] The water heating system can minimise the time delay in delivery of hot water at a desired temperature to the system outlet. [011] The valves can contain integral sensors and actuators which operate to direct water flow. [012] The water flow can be directed by at least one valve controlled by an electronic controller responding to at least one sensor. [013] The main water heater can be a tankless instantaneous gas water heater.

C 10029 3 [0141 The hot water store can be a water storage tank with an electric heating element. [015] According to a further embodiment of the invention, there is provided a hot water supply system having a system inlet and a system outlet, the system including a main water heater having a first inlet and a first outlet and an auxiliary water heater having a second inlet and a second outlet, wherein: the auxiliary heater and the main heater are connected in series or in bypass configuration. [016] The inlet of the auxiliary heater can be connected to the outlet of the main heater. [017] The inlet auxiliary heater can be connected to the outlet of the main heater by a switchable valve having an inlet port and first and second outlet ports, the outlet of the auxiliary heater being connected to the system outlet, the outlet of the main heater being connected to the inlet port, and the inlet of the auxiliary heater being connected to the first outlet port, and the second outlet port being connected to the system outlet. [018] The outlet of the auxiliary heater can be connected to the inlet of the main heater. [019] The outlet of the auxiliary heater can be connected to the inlet of the main heater via a bypass path including a switchable valve. [020] The outlet of the auxiliary heater can be connected to the outlet of the system via a bypass path. [021] The inlet of the auxiliary heater can be connected to the outlet of the main heater. [022] The system can include an auxiliary heater temperature sensor to sense the temperature of the stored water. [023] The system can include an outlet temperature sensor adapted to sense the temperature of the outlet water. [024] The system can include a main heater temperature sensor adapted to sense the temperature of the hot water in the main heater. [025] The system can include a controller responsive to a flow sensor to activate the main heater.

C 10029 4 [026] The system can include an on-demand main heater and a booster heater, wherein the outlet of the main heater and the outlet of the booster heater are connected as inputs to a controllable valve which is adapted to produce an outlet flow within a predetermined temperature range. [027] The system can include control means responsive to the temperature of the water supplied from the main heater to switch off the booster heater or to close off the flow of from the booster heater via the controllable valve when the main heater outlet temperature reaches a predetermined value. Brief description of the drawings [028] An embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [029] Figure 1 is a schematic illustration of a water heating system according to an embodiment of the invention; [030] Figure 2 is a schematic illustration of an alternative embodiment of the invention. [031] Figure 3 is a schematic illustration of a further alternative embodiment of the invention and is applicable to both versions shown in Figure 1 and Figure 2. [032] The numbering convention used in the drawings is that the digits in front of the full stop indicate the drawing number, and the digits after the full stop are the element reference numbers. Where possible, the same element reference number is used in different drawings to indicate corresponding elements. [033] It is understood that, unless indicated otherwise, the drawings are intended to be illustrative rather than exact representations, and are not necessarily drawn to scale. The orientation of the drawings is chosen to illustrate the features of the objects shown, and does not necessarily represent the orientation of the objects in use. Detailed description of the embodiment or embodiments [034] The invention will be described with reference to the embodiments shown in the drawings. [035] Figure 1 shows a water heating system including a first water heater 1.030 and a second water heater 1.002. A thermally actuated 3-way valve 1.070 having three ports: an input port 1.075 and two output ports 1.071, 1.073. The input port 1.075 is connected to the output 1.036 of the first water heater 1.030. The first C 10029 5 output 1.071 of the valve 1.070 is connected to the input 1.021 of the second heater 1.002. The second output valve 1.073 is connected to the system output 1.050. The output 1.014 of the second heater 1.002 is also connected to the system output 1.050. [036] The valve 1.070 can be an autonomously controlled device with integral temperature sensor and operating mechanism. Alternatively the valve can include a flow control mechanism which is controlled via an external temperature sensor such as 1.042 and a controller such as 1.004. [037] Alternatively, individual controllable valves can be used to implement the flow control. [0381 The second heater 1.002 can be a storage heater adapted to maintain a volume of water within a predetermined temperature range. The second water heater is thermostatically controlled. A stored water temperature sensor provides an indication of the temperature eof the water in the second heater. The second heater can be set to operate in the same temperature range as the first heater or in a different temperature range. [039] A water flow sensor 1.022 is connected in the permanent flow path of the system so that it detects the magnitude of the flow or absence of flow of water. The flow sensor can initiate the heater of the first water heater 1.030. [040] The first water heater 1.030 can be an instantaneous gas heater. The second heater 1.002 can be an electric storage water heater. The volume of the storage heater can be sufficient to contain the cooled water from the first heater 1.030. [041] The storage water heater 1.002 can have a thermostatic control arrangement designed to maintain the temperature of the water in the storage tank within the predetermined temperature range. The thermostatic control arrangement is shown schematically as a temperature sensor 1.006 connected to the mains switch 1.010 which controls the delivery of electric power from the mains 1.008 to the heating element 1.009. [042] Of course, other thermostatic arrangements can be used without departing from the inventive concept. For example, thermostatic control can include an electronic controller responsive to the temperature sensor 1.006 to operate the power switch 1.010. the connected to controller 1.004, the controller operating the electric switch 1.010 C10029 6 [043] In operation, the second heater 1.002 maintains water in its container within a predetermined storage temperature range. When the flow sensor detects the flow of water it turns the first water heater 1.030 on. Because the initial water flow from the first water heater 1.030 is below the threshold, the thermally activated valve 1.070 initially directs the water from the first heater outlet 1.036 to the inlet 1.021 of the second heater 1.002. This displaces the water in the second water heater through its outlet 1.014 to the system outlet 1.050. Thus the water in the second heater is delivered to the system outlet 1.050, while the cooled water from the first heater 1.030 is stored in the second water heater. When the first heater 1.030 has heated its outlet water to the predetermine threshold temperature, the thermally activated valve 1.070 switches the flow to its second output port 1.073 and thence to the system outlet 1.050, and closes off the flow via its first outlet port 1.071. Thus the flow through the second water heater 1.002 is stopped. [044] Thus, when the output temperature of the first heater 1.030 is below the trigger temperature of the thermally actuated valve 1.070, water is delivered to the system outlet 1.050 from the second heater 1.002, and when the output temperature of the first heater 1.030 is above the trigger temperature of the thermally actuated valve, the second heater is bypassed, and water is delivered to the system outlet 1.050 from the outlet 1.036 of the first heater 1.030. [045] The thermostatic control of the second water heater then causes the second heater to heat the stored water to the predetermined storage temperature range and to maintain it within that temperature range. [046] Thus the second heater should have a capacity sufficient to contain the water delivered from the first heater before the first heater reaches the trigger temperature of the valve 1.070. [047] Figure 2 illustrates an alternative embodiment of the invention. A first heater 2.030 and a second heater 2.002 have their respective outlets 2.036 and 2.014 connected to inlets 2.083, 2.081 respectively of a two-inlet port/one outlet port thermally actuated valve 2.080. [048] In this arrangement, the thermally actuated valve 2.080 acts to block flow via its inlet port 2.083 and to permit flow via its second inlet port 2.081 to its outlet port 2.085 and hence to the system outlet 2.050 when the temperature of the water from the outlet 2.014 of the second heater is above the trigger temperature of the valve 2.080. When the temperature at outlet 2.014 falls below the trigger temperature, the valve 2.080 blocks flow via its second inlet port 2.081 and permits C10029 7 flow to its outlet port 2.085 and hence to the system outlet 2.050 via the inlet port 2.083. Thus, the cooled water from the first heater is again delivered to the storage bottle of the second water heater 2.002 until the first heater reaches the trigger temperature of the valve. Valve 2.080 can be mounted in close proximity to the outlet 2.014 of the second heater 2.002. (049] The second water heater 2.002 is thermostatically controlled to maintain the water within a predetermined temperature range. [050] Figure 3 is an alternative arrangement of the system of Figure 1 adapted to contain an auxiliary heater 3.002 and main heater 3.030 within a single housing 3.120. This reduces the length of connecting pipe between which is external to both heaters. As shown in Figure 3, the auxiliary heater 3.002 and the main heater 3.030 can be closely mounted side by side. The auxiliary heater can be placed proximate to, adjacent to, or contiguous with the main heater so that the length of the connecting pipe can be reduced or minimized. The connecting pipe 3.102 can be substantially contained within the main heater, delivering water from the hottest part of the heat exchanger system, and optionally can be part of the heat exchanger of the main heater, and deliver heated water to the auxiliary tank via a short connexion. [051] In this specification, reference to a document, disclosure, or other publication or use is not an admission that the document, disclosure, publication or use forms part of the common general knowledge of the skilled worker in the field of this invention at the priority date of this specification, unless otherwise stated. [052] In this specification, terms indicating orientation or direction, such as "up", "down", "vertical", "horizontal", "left", "right" "upright", "transverse" etc. are not intended to be absolute terms unless the context requires or indicates otherwise. These terms will normally refer to orientations shown in the drawings. [053] Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of". A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear. [054] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.

C10029 8 [055] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

Claims

1. A water heating system having a system inlet and a system outlet, the system including: a first water heater having a first inlet and a first outlet; a second water heater having a second inlet and a second outlet; and a flow direction control valve; wherein the first outlet is connected to the flow direction control valve, and wherein the flow direction valve controls the flow of water from the first heater so that water from the first heater flows to the second inlet or directly to the system outlet.

2. A water heating system as claimed in claim 1, wherein the flow direction control valve has a first port being an inlet port, and a second port being a first outlet port, and a third port being a second outlet port, and wherein the first outlet is connected to the first port, the first outlet port of the flow direction valve is connected to the second inlet, and the second outlet port and the second outlet are connected to the system outlet.

3. A water heating system as claimed in claim 1, wherein the flow direction control valve has a first inlet port, a second inlet port, and an outlet port, and wherein the first outlet is connected to the first inlet port, the second inlet port is connected to the second outlet, and the outlet port is connected to the system outlet.

4. A water heating system including a main water heater delivering heated water within a first predetermined temperature range and a hot water storage container; the hot water storage container maintaining water at a temperature within a second pre-determined temperature range; the water heating system including at least one automatically operating valve capable of directing water flow through the hot water storage container or to a by pass circuit; whereby the outlet of the main water heater is connected by the automatically operating valve to the outlet of the water heating system through the hot water storage container or directly through the by-pass circuit. 10

5. A water heating system as claimed in claim 4, wherein the automatically operating valve is a temperature sensitive diversion valve adapted to cause water from the first water heater to flow through the hot water storage container when the water temperature is below the first pre-determined temperature range and through the by-pass circuit when the water temperature is with-in or greater than the first pre-determined temperature range.

6. A water heating system as claimed in claim 4, wherein the automatically operating valve is a temperature sensitive mixing valve having first and second inlet ports and an outlet port, and wherein the outlet of the hot water storage container is connected to the second inlet port and the by-pass circuit is connected to the first inlet port , wherein the temperature sensitive mixing valve directs the flow from the hot water storage container to the system outlet when the water temperature in the by-pass path is below the first pre-determined temperature range and the flow from the by-pass circuit to the system outlet when the water temperature in the by-pass path is within or greater than the first pre determined temperature range.

7. A water heating system as claimed in any one of the preceding claims, wherein the water heating system is adapted to minimise the time delay in delivery of hot water at a second pre-determined temperature to the system outlet.

8. A water heating system as claimed in any one of claims 4 to 7, wherein the automatically operating valve contains an integral temperature sensor and actuators which operate to direct water flow in response to the sensor.

9. A water heating system as claimed in any one of claims 4 to 7, wherein the water flow can be directed by at least one valve controlled by an electronic controller responding to at least one temperature sensor.

10. A water heating system as claimed in any one of the preceding claims, wherein the first or main water heater is an instantaneous gas water heater.

11. A water heating system as claimed in any one of the preceding claims, wherein the hot water store is a water storage tank with an electric heating element.

12. A hot water supply system having a system inlet and a system outlet, the system including a main water heater having a first inlet and a first outlet and an 11 auxiliary water heater having a second inlet and a second outlet, and a flow direction control valve, wherein: the auxiliary heater and the main heater are connected in series or in bypass configuration by the flow direction control valve, whereby water from the main water heater flows to the system outlet either via the auxiliary heater or directly.

13. A hot water supply system as claimed in claim 12, including a first temperature sensor sensing the temperature of water from the main heater, the flow direction control valve being responsive to the first temperature sensor.

14. A hot water supply system as claimed in claim 12 or claim 13, wherein the flow direction control valve is a switchable valve having an inlet port and first and second outlet ports, the inlet of the auxiliary heater is connected to the outlet of the main heater by the switchable valve, the outlet of the main heater being connected to the inlet port, the outlet of the auxiliary heater being connected to the system outlet, and the inlet of the auxiliary heater being connected to the first outlet port, and the second outlet port being connected to the system outlet.

15. A system as claimed in any one of claims 12 to 14, including an auxiliary heater temperature sensor to sense the temperature of the stored water.

16. A system as claimed in any one of claims 12 to 15, including a flow sensor arranged to detect the flow of water through the system, and a controller responsive to the flow sensor to activate the main heater.

17. A water heating module including a water heating system as claimed in any one of the preceding claims, contained in a single housing.

18. A heated water supply system substantially as herein described with reference to the accompanying drawings.

19. A method of delivering heated water to a water heating system outlet, the method including the steps of: heating water in a first water heater; storing heated water from the first heater in a heated water store, in response to a use of water from the water heating system, diverting water from the first water heater into the heated water store when the temperature of the water from the first heater is below a first temperature while delivering water from the heated water store to the system outlet, and 12 delivering water from the first heater to the system outlet when the temperature of the water from the first heater is greater than the first temperature.