AU2011201539A1 - Storage Water Heater - Google Patents

Abstract

A water or fluid heater including: a chamber housing a heating means such as a burner; a storage tank mounted above the chamber; a heat exchanger tube mounted within the chamber forming part of a fluid circulation path between the storage tank and the heat exchanger tube, the heat exchanger tube being inclined or vertically orientated to induce natural convective movement of fluid through the circulation path (i.e. thermosyphoning); a chamber flue path in thermal connection with the storage tank to allow hot gases from the chamber to heat a surface of the storage tank. Preferably, the storage tank further incorporates a section utilised as a solar heat storage reservoir and an air bladder to provide pressure relief within the tank.

Description

1 Storage Water Heater Field of the Invention 5 The present invention relates to a gas or oil fuelled storage water heater. The present invention has been developed particularly for use as a storage water heater and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular use and may also be used to heat other fluids, such as oil. 0 Background of the Invention Conventional gas or oil fuelled storage water heaters work on a principle of a gas or oil fuelled burner which creates heat after the gas or oil fuel is mixed with air and burnt in a combustion chamber. The hot combustion products are directed upwards and into contact with the tanks external or internal flue passage walls so that the heat energy is passed into the 5 water in the tank. The combustion efficiency of conventional gas or oil fuelled storage water heaters is limited by the temperature of the water in the tank. As the water in the tank heats up the combustion products ability to pass the heat energy into the water inside the tank diminishes and consequently the combustion products temperature exiting the water heater cannot be '0 lower than the water temperature in the tank. The design and operating principles of conventional gas or oil fuelled storage water heaters only enable the units to achieve a high efficiency condensing performance in the initial stages of the heat up period of the water in the tank. The combustion efficiency of conventional gas or oil fuelled storage water heaters is therefore in the range of 75 to 85% as they cannot maintain a condensing state throughout the 25 entire heating up period of the water in the tank. Many conventional gas or oil fuelled storage water heaters also use a pilot flame mechanism to enable the unit to ignite the main burner when the unit's thermostat controller / gas valve turns on the main burner. The combustion efficiency of the pilot flame is also limited by the water temperature inside the tank. 30 Pilot flames also cause a thermal draft through the unit as the hot burnt combustion products flow up from the combustion chamber, through the heat exchanging areas of the tank and finally exit the unit.

2 This slow draft can over time be the cause of significant heat loss from the stored hot water in the tank which will require the main burner to activate and reheat the water up to its desired ,5 storage temperature. In order to overcome the pilot flame heat losses some conventional gas or oil fuelled storage water heaters use an electrically powered automatic ignition device to light the main burner however these devices add significant cost to the manufacturing price and installation cost of the unit. -0 Electrically powered gas or oil fuelled storage water heaters will not function if there is an electricity power supply failure as they require electricity to turn on the main burner, conventional pilot flame water heaters do not require any electricity to function normally. Because Conventional gas or oil fuelled storage water heaters utilise allocated sections of the tanks wall as a primary and secondary heat exchanging surfaces their design -5 requires dedicated areas and passages on the tank itself to enable the burnt combustion products to flow past and through to ensure that adequate heat exchanging occurs. These heat exchanging areas and passages add complexity and cost to the manufacturing process of the heater. Conventional gas or oil fuelled storage water heaters generally use the bottom of the .0 tank as the primary heat exchanging area which forms the top lid or section of the combustion chamber. This design function can also cause serious issues when the heater is exposed to a water supply which contains contaminants such as mud, silt or high levels of minerals. The contaminants in the water supply tend to accumulate or settle in the bottom of the tank and consequently over time build up and form a layer over the bottom section of the tank. This 55 layer of contaminants will over time reduce the heat exchanging process on the bottom of the tank which will initially lower the combustion efficiency of the unit. In time this issue will cause the bottom of the tank to overheat and eventually rupture due to heat stress. It is common to find accumulated layers of contaminants up to 200 / 300mm in the bottom of storage water heaters exposed to contaminated water supplies which causes a terminal tank 60 failure and destroys the unit. Conventional gas or oil fuelled storage water heaters which operate at high pressure generally use a relief valve to ensure the pressure in the tank remains safe during the heat up period of the water in the tank. During the heat up period the water in the tank expands and there is a corresponding increase in pressure which must be relieved so that the tank does not 65 rupture. The pressure relief valve opens intermittently as the pressure increases and ejects water and heat energy from the unit which is discarded and not used by the user.

3 These water and energy losses on average equate to 5 litres per day on a domestic use pattern and over the life of the heater are responsible for significant water and energy losses from the unit. F0 In summary conventional gas or oil fuelled storage water heaters have the following design deficiencies which are common to all units. a) Inability to maintain a high combustion efficiency due to the water temperature relationship with the exiting combustion products. b) Heat losses which are caused by the pilot flame thermal draft through the unit. F5 c) Complexity of design in relation to the flue passages and heat exchanging areas of the tank which requires expensive components to enable the hot combustion products to heat the water in the tank. d) Early unit failure in circumstances whereby the unit is supplied with poor quality water which contains contaminates or impurities which accumulates in the bottom 0 of the tank. e) Water and energy losses which are caused by the pressure relief valve in normal operation. Object of the Invention It is the object of the present invention to substantially overcome and in many cases eliminate 5 the design deficiencies of the prior art as has been described above. 90 95 00 4 Summary of the Invention Accordingly, in a first aspect the present invention provides a storage water heater comprising: a chamber; 5 a heating means within the chamber, at least one primary heat exchanger mounted within the chamber above the heating means; a fluid inlet for supplying fluid to said one heat exchanger; a fluid outlet from said one heat exchanger; 0 a flue outlet which is connected to the heating means; a storage tank which is mounted above the chamber which is fitted with a fluid inlet and fluid outlet which is connected to the said heat exchanger, a fluid inlet and fluid outlet which are mounted on the tank for external connection and use and a section of the tank surface area which is utilised as a secondary combustion products heat 5 exchanger. The heating means is preferably a burner, most preferably a gas or oil burner and the chamber is a combustion chamber. The primary heat exchanger is preferably a finned type with multiple pipes running in parallel though the heat exchanger. It is positioned above the burner in an inclined or vertical '0 orientation so as to cause an upward thermal flow of the fluid within the in parallel pipes when the burner or pilot flame is on and heat is being absorbed by the water within the primary heat exchange pipes. As the water in the inclined or vertical primary heat exchanger pipes heats up it rises and flows upwards through the heat exchanger and exits via an outlet fitting at the top. After 25 exiting the top fitting the thermally flowing hot water enters an inclined / vertical connection pipe which delivers it into the storage tank. The thermal flow which is created inside the inclined primary finned heat exchanger also causes water inside the storage tank to be sucked down a separate connection pipe which delivers the cold tank water into the bottom finned heat exchanger inlet fitting. 30 The thermal flow which is created by the burner and the inclined primary finned heat exchanger is sufficient to cause the cold water inside the tank to be circulated thought the heat exchanger, heated as it passes through, and returned to the tank.

5 As the tank water heats up the water being delivered into the bottom fitting of the inclined primary finned heat exchanger becomes hotter and conversely the hot water exiting ,5 the top fitting becomes hotter as well. As the hot water enters the tank it mixes with the water within the tank which creates a mean tank temperature which is significantly lower than the water temperature which is flowing out of the primary heat exchanger. A thermal current is created in the storage tank which is caused by the thermal flow -0 from the inclined primary finned heat exchanger which causes the tank water to maintain a consistent temperature throughout the water heating process inside the tank which does not cause hot spots or stratification. The burner preferably includes a fuel valve with a thermostat sensor for supplying fuel thereto and inlet vents to allow air to enter the combustion chamber to mix with the fuel. -5 The fuel valve thermostat sensor and the thermal return and delivery pipes from the inclined primary finned heat exchanger are positioned on the tank so as to ensure that the bottom section of the tank is not heated and thereby remains colder. After the combustion products have passed through the primary inclined finned heat exchanger they are directed into a secondary heat exchanging cavity which is positioned on .0 the bottom of the storage tank which is the section of the tank which contains the water which is not heated by the primary combustion products and is thereby colder. Some small heat contribution from the secondary combustion products from the main burner and pilot flame will add heat energy to the cold section of the tank however if the heater is used in a normal domestic use pattern the bottom cold section of the tank will be consistently replaced with 55 cold water as hot water is drawn off / used from the top hot section of the tank. The tank wall in the secondary heat exchanging cavity is exposed to the secondary combustion products which flow through the cavity and cause the remaining heat energy from the secondary combustion products to be passed into the colder water which is adjacent to the exposed tank wall in the secondary heat exchanging cavity. 60 The large temperature differential between the secondary combustion products and the dedicated colder water section of the secondary heat exchanging cavity causes condensation of the combustion products to occur which ensures that a high combustion / thermal efficiency is maintained throughout the tank heating process. After the secondary combustion products pass through the secondary heat exchanging 65 cavity they are directed into a vertically orientated flue duct which delivers the flue products to a flue terminal which discharges the combustion products from the unit.

6 The storage tank is fitted with an air balloon / bladder mounted inside the tank which has a set volume of air contained in the sealed balloon / bladder. The balloon / bladder has a sufficient air volume inside it that compresses when the pressure rises inside the tank due to '0 the water temperature rise and subsequent expansion. The compressing air within the balloon / bladder prevents the storage tanks pressure relief valve from opening during normal operation and thereby saves water and energy which is normally wasted in conventional gas / oil fuelled storage water heaters. The same air compression principle may be achieved by trapping air in the top section of the tank. F5 In a second aspect, the present invention provides a storage water heater comprising: a chamber; a heating means within the chamber, at least one primary heat exchanger mounted within the chamber above the heating means; 0 a fluid inlet for supplying fluid to said one heat exchanger; a fluid outlet from said one heat exchanger; a flue outlet which is connected to the heating means; a storage tank which is mounted above the chamber which is fitted with a fluid inlet and fluid outlet which is connected to the said heat exchanger, a fluid inlet and fluid 5 outlet which are mounted on the tank for external connection and use, a fluid inlet and fluid outlet fitting which can be connected to a solar heater, a lower section of the tank which is dedicated for use as a solar water storage reservoir and a section of the tank surface area which is utilised as a secondary combustion products heat exchanger. 90 The second aspect models function is identical to the first aspect models function except for the addition of a section of the storage tank to be utilised as a solar storage reservoir. The section of the tank which is dedicated as the solar storage reservoir is below the controlling thermostats temperature sensor and the return and delivery connection pipes from 95 the primary inclined finned heat exchanger. This configuration ensures that the solar reservoir is not heated by the primary combustion products and thereby is primarily heated by the solar heater when the sun is contributing heat energy.

7 0 Some small heat contribution from the secondary combustion products from the main burner and pilot flame will add heat energy to the solar reservoir however if the heater is used in a normal domestic use pattern the bottom section of the tank will be consistently replaced with cold water as hot water is drawn off / used from the top hot water section of the tank. The solar reservoir section of the tank functions as a pre heater of the water prior to its 5 elevation into the top section of the tank which occurs during a hot water draw off / use. Any energy contributed by the solar heater will create a fuel saving. In some circumstances the solar heater can raise the entire tank temperature well above the burners controlling thermostat temperature setting which effectively increase the solar storage capacity to the full tank volume. 0 Both the first and second aspect of the invention as described above do not require the air balloon / bladder or air gap principle to function however they will eject water and energy via the pressure relief valve as conventional storage units do. Conversely the air balloon / bladder or air gap principle can be applied to any pressure tank which holds a fluid which expands upon being heated by any energy source. 5 To achieve a higher combustion efficiency a second finned heat exchanger can be fitted to both the first and second aspect of the invention's vertical flue duct after the second heat exchanger cavity. This second finned heat exchanger would receive the incoming cold water prior to the water entering the storage tank so that it would absorb heat energy from the combustion products after they have passed through the second heat exchanging cavity. This '0 second finned heat exchanger will only recover heat energy when the water is flowing into the tank and the mains burner and pilot flame are burning. This configuration can deliver combustion products out of the flue terminal outlet at a temperature which is lower than the ambient air temperature and thereby achieve a very high combustion / thermal efficiency. 25 30 8 Brief Description of the Drawings ,5 Preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic front view of a first embodiment of a gas or oil fuelled storage water heater showing all inlet and outlet pipe fixtures, flue terminal outlets and air inlet vent. Fig. 2 is a schematic left side view of a first embodiment of a gas or oil fuelled -0 storage water heater showing the left side inlet and outlet pipe fixtures, flue terminal outlet and air inlet vent. Fig. 3 is a front sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the internal components of the heater. Fig. 4 is a left side sectional view of a first embodiment of a gas or oil fuelled storage -5 water heater showing the internal components of the heater. Fig. 5 is a left side sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the combustion products pathway through the combustion chamber, secondary heat exchanging cavity, flue duct and flue terminal during main burner and pilot flame operation. .0 Fig. 6 is a left side sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the combustion products pathway through the combustion chamber, secondary heat exchanging cavity, flue duct and flue terminal during pilot flame operation. Fig. 7 is a front sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the combustion products pathway through the secondary heat .5 exchanging cavity, flue duct and flue terminal during main burner and pilot flame operation. Fig. 8 is a left side sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the cold and hot water flow paths during the main burner operation mode when the tank is full of cold water. Fig. 9 is a front sectional view of a first embodiment of a gas or oil fuelled storage 60 water heater showing the cold and hot water flow paths during the main burner operation mode when the tank is full of cold water. Fig. 10 is a left side sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the warm and hot water flow paths during the main burner operation mode when the tank is partially heated. 65 Fig. 11 is a sectional view of A - A in the direction of the arrows from Fig. 10 showing the gas valve position and the delivery outlet and return inlet from the combustion chamber finned heat exchanger.

9 Fig. 12 is a front sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the secondary heat exchanging cavity combustion products pathways '0 during the main burner / pilot flame operation. Fig. 13 is a front sectional view of a first embodiment of a gas or oil fuelled storage water heater showing the condensation droplet pathways during the main burner operation. Fig.14 is a schematic front view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing all inlet and outlet pipe '5 fixtures, flue terminal outlets and air inlet vent. Fig. 15 is a schematic front view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the internal components of the heater. Fig. 16 is a schematic left side view of a second embodiment of a gas or oil fuelled 0 storage water heater with a solar pre heating tank section showing all the left side inlet and outlet pipe fixtures, flue terminal outlet and air inlet vent. Fig. 17 is a left side sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the internal components of the heater. 5 Fig. 18 is a left side sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the combustion products pathway through the combustion chamber, secondary heat exchanging cavity, flue duct and flue terminal during main burner and pilot flame operation. Fig. 19 is a left side sectional view of a second embodiment of a gas or oil fuelled 90 storage water heater with a solar pre heating tank section showing the combustion products pathway through the combustion chamber, secondary heat exchanging cavity, flue duct and flue terminal during pilot flame operation. Fig. 20 is a front sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the combustion products pathway 95 through the secondary heat exchanging cavity, flue duct and flue terminal during main burner and pilot flame operation. Fig. 21 is a left side sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the cold and hot water flow paths during the main burner operation mode when the tank is full of cold water.

10 0 Fig. 22 is a front sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the cold and hot water flow paths during the main burner operation mode when the tank is full of cold water. Fig.23 is a left side sectional view of a second embodiment of a gas or oil fuelled storage water heater with a solar pre heating tank section showing the warm and hot water 5 flow paths during the main burner operation mode when the tank is partially heated. Detailed Description of the Preferred Embodiments Figs. 1 to 13 show a gas or oil fuelled storage water heater 1 according to a first preferred embodiment of the present invention. 0 As shown in Figs. 3 and 4 the water heater 1 comprises a combustion chamber 2 housing a gas burner 3 and pilot flame 11 at a lower portion thereof, a first inclined finned heat exchanger 4 is located directly above the gas burner 3 and a second heat exchanging cavity 5 is located directly above the first finned heat exchanger 4. The second heat exchanging cavity 5 is fitted with a condensate drain pipe 18 which enables the condensate 5 which occurs in the second heat exchanging cavity 5 to be removed from the water heater 1 via outlet fitting 19. A flue duct pipe 7 is connected to the second heat exchanging cavity 5 which is also connected to an outlet flue terminal 8. An insulated tank 6 is mounted above the combustion chamber 2 and is connected to the first inclined finned heat exchanger 4 via hot delivery connection pipe 9 and cold delivery connection pipe 10 to the bottom of the first '0 inclined finned heat exchanger 4. The combustion chamber 2 is mounted in an insulated case 23 which supports the insulated tank 6. A gas valve 12 is mounted on the insulated tank 6 which is fitted with a temperature sensor which activates and deactivates the gas valve 12. The gas valve 12 is also connected to a gas inlet fitting 22 via a connecting pipe. The insulated tank 6 has a water inlet connection 13 which is connected to a pipe 14 which directs 25 the incoming water towards the bottom of the insulated tank 6. Water inlet 13 is also connected to an inlet fitting 20 via a connecting pipe. The insulated tank 6 also has a water outlet connection 15 which is the hot outlet port for the hot water in the insulated tank 6. Water outlet connection 15 also is connected to an outlet fitting 21 via a connecting pipe. The insulated tank 6 is covered by a protective outer case 16 and a front cover 17 which protects 30 the water heater 1 from weather. The front cover 17 is fitted with air inlet vents 24 which supplies air to the burner 3 and pilot flame 11.

11 The burner 3 is most preferably a gas or oil burner and the combustion chamber 2 is ,5 mounted in an insulated case 23 which supports the insulated tank 6 and prevents heat loss from the water heater 1 during burner 3 and pilot flame 11 operations. As shown in Figs. 3 and 4 the primary heat exchanger 4 is preferably a finned type with multiple pipes running in parallel though the primary heat exchanger 4. It is positioned above the burner 3 in an inclined or vertical orientation so as to cause an upward thermal -0 flow of the fluid within the in parallel pipes when the burner 3 or pilot flame 11 is on and heat is being absorbed by the water within the primary heat exchange 4 pipes. As shown in Figs. 8, 9, 10 and l Ithe water in the inclined or vertical primary heat exchanger 4 pipes flows upwards as it is heated through the heat exchanger and exits via an outlet fitting at the top. After exiting the top fitting the thermally flowing hot water enters an -5 inclined / vertical connection pipe 9 which delivers it into the insulated storage tank 6. The thermal flow which is created inside the inclined primary finned heat exchanger 4 also causes water inside the insulated storage tank 6 to be sucked down a separate connection pipe 10 which delivers the cold tank water into the bottom of the primary finned heat exchanger 4 inlet fitting. .0 The position of the thermal flow tank connection fittings 25 and 26 are such that the hot water entering the insulated storage tank 6 via entry fitting 25 is below and diagonally opposed to the cold suck delivery fitting 26, this causes some of the hot water flowing into the insulated storage tank 6 from fitting 25 to be draw / sucked into fitting 26 which ensures that the water flowing into the first primary finned heat exchanger 4 is preheated to an extent .5 that its temperature is raised enough to prevent condensation occurring inside the combustion chamber 2. The thermal flow which is created by the burner 3, pilot flame 11 and the inclined primary finned heat exchanger 4 is sufficient to cause the cold water inside the insulated storage tank 6 to be circulated thought the inclined primary finned heat exchanger 4, heated 60 as it passes through, and returned to the insulated storage tank 6. As the insulated storage tank 6 water heats up the water being delivered into the bottom fitting of the inclined primary finned heat exchanger 4 becomes hotter and conversely the hot water exiting the top fitting becomes hotter as well. As the hot water enters the insulated storage tank 6 it mixes with the water within the 65 insulated storage tank 6 which creates a mean tank temperature which is significantly lower than the water temperature which is flowing out of the primary finned heat exchanger 4.

12 A thermal current is created in the insulated storage tank 6 which is caused by the thermal flow from the inclined primary finned heat exchanger 4 which causes the insulated storage tank 6 water to maintain a consistent temperature throughout the water heating '0 process inside the insulated storage tank 6 which does not cause hot spots or stratification. As shown in Figs. 5, 6 and 7 the burner 3 preferably includes a fuel valve 12 with a thermostat sensor for supplying fuel thereto and inlet vents 24 to allow air to enter the combustion chamber 2 to mix with the fuel. The fuel valve 12 thermostat sensor and the thermal return and delivery pipes 10 and '5 9 from the inclined primary finned heat exchanger 4 are positioned on the insulated storage tank 6 so as to ensure that the bottom section of the insulated storage tank 6 is not heated and thereby remains colder. After the combustion products have passed through the primary inclined finned heat exchanger 4 they are directed into a secondary heat exchanging cavity 5 which is positioned 0 on the bottom of the insulated storage tank 6 which is the section of the insulated storage tank 6 which contains the water which is not heated by the primary combustion products and is thereby colder. Some small heat contribution from the secondary combustion products from the burner 3 and pilot flame 11 will add heat energy to the cold section of the insulated storage tank 6 however if the heater is used in a normal domestic use pattern the bottom cold 5 section of the insulated storage tank 6 will be consistently replaced with cold water as hot water is drawn off / used from the top hot section of the insulated storage tank 6. As shown in Fig 12 the tank wall in the secondary heat exchanging cavity 5 is exposed to the secondary combustion products which flow through the secondary heat exchanging cavity 5 and recovers heat energy from the from those secondary combustion 90 products which is passed into the colder water which is adjacent to the exposed insulated storage tank 6 wall in the secondary heat exchanging cavity 5. As shown in Fig 13 the large temperature differential between the secondary combustion products and the dedicated colder water section of the secondary heat exchanging cavity 5 causes condensation of the combustion products to occur which ensures that a high 95 combustion / thermal efficiency is maintained throughout the insulated storage tank 6 heating process. After the secondary combustion products pass through the secondary heat exchanging cavity 5 they are directed into a vertically orientated flue duct 7 which delivers the flue products to a flue terminal 8 which discharges the combustion products from the water heater 00 1.

13 The insulated storage tank 6 is fitted with an air balloon / bladder mounted inside the tank (not shown in drawings) which has a set volume of air contained in the sealed balloon / bladder. The balloon / bladder has a sufficient air volume inside it that compresses when the pressure rises inside the insulated storage tank 6 due to the water temperature rise and 5 subsequent expansion. The compressing air within the balloon / bladder prevents the insulated storage tank 6 pressure relief valve from opening during normal operation and thereby saves water and energy which is normally wasted in conventional gas / oil fuelled storage water heaters. The same air compression principle may be achieved by trapping air in the top section of the tank 0 (not shown in drawings). Figs. 14 to 23 show a solar boosted gas or oil fuelled storage water heater 2 according to a second preferred embodiment of the present invention. The same reference numerals apply in the same context as the water heater 1 Figs 5 with the addition of some new numerals to denote the solar boosting function. The water heater 2 gas combustion functions are identical to the water heater 1 embodiment except for the addition of a section of the insulated storage tank 6 to be utilised as a solar storage reservoir as shown in Fig. 15 by the area defined by the arrows and reference lines 27. 10 The solar reservoir section of the tank 27 which is dedicated as the solar storage reservoir is below the controlling thermostats temperature sensor 12 and the return and delivery connection fittings 20 and 21 into the insulated storage tank 6 from the primary inclined finned heat exchanger 4 . This configuration ensures that the solar reservoir section of the tank 27 is not heated by the primary combustion products and thereby is primarily 25 heated by the solar heater (not shown) when the sun is contributing heat energy. Some small heat contribution from the secondary combustion products from the burner 3 and pilot flame 11 will add heat energy to the solar reservoir section of the tank 27 however if the water heater 2 is used in a normal domestic use pattern the bottom section of the insulated storage tank 6 will be consistently replaced with cold water as hot water is 30 drawn off / used from the top hot water section of the insulated storage tank 6. The solar reservoir section of the tank 27 functions as a pre heater of the water prior to its elevation into the top section of the insulated storage tank 6 which occurs during a hot water draw off / use. Any energy contributed by the solar heater will create a fuel saving.

14 Fig. 15 shows the solar heater (not shown) delivery and return fittings on the insulated ,5 storage tank 6. Water from the solar reservoir section of the tank 27 is sucked out of fitting 29 and circulated through the solar heater (not shown) and then returned to the solar reservoir section of the tank 27 via fitting 28. Both fittings 28 and 29 are connected to connecting pipes and connection fittings on the water heater 2 front cover 17 as shown in Figs 14 and 15. The flow circuit ensures that the entire water volume of the solar reservoir section of the tank 27 -0 is heated by the solar heater (not shown) when the sun is contributing heat energy. In some circumstances the solar heater (not shown) can raise the entire tank temperature well above the water heater 2's controlling thermostat temperature setting which effectively increase the solar storage capacity to the full insulated storage tank 6 volume. The solar reservoir section of the tank 27 can also be utilised for other forms of heat -5 recovery which are not solar based where available. All embodiments of the water heater described above can be amended to use electronic controls and components such as combustion fans and water circulation pumps which may provide some benefit for particular applications of the invention. Although preferred embodiments of the present invention have been described, it will .0 be apparent to skilled persons that modifications can be made to the above embodiments and to the operation thereof. .5 60 65

Claims (21)

1. A water or fluid heater including a chamber; 5 a heating means disposed within the chamber, at least one primary inclined or vertically orientated in parallel tube finned heat exchanger mounted within the chamber above the heating means; a fluid inlet for supplying fluid to bottom inlet fitting of said one heat exchanger; a fluid outlet from the top of the said one heat exchanger; 0 a flue outlet which is connected to the secondary heat exchanging cavity; an insulated storage tank which is mounted above the chamber which is fitted with a fluid inlet and fluid outlet which is connected to an inclined or vertically orientated in parallel tube finned heat exchanger, a fluid inlet and fluid outlet which are mounted on the tank for external connection and use and a section of the tank surface area 5 which is utilised as a secondary combustion products heat exchanger.

2. The water heater as claimed in claim 1, wherein the heating means is a burner and the chamber is a combustion chamber. 10

3. The water heater as claimed in claim 2, wherein the heating means is a gas or oil burner.

4. The water heater as claimed in claim 1, 2 or 3, wherein the heating means is disposed at a lower section of the combustion chamber. 25

5. The water heater as claimed in any one of the preceding claims, wherein the finned heat exchanger is inclined or vertically orientated with a series of in parallel tubes within the finned heat exchanger so as to cause a thermal flow of fluid when heated. 30

6. The water heater as claimed in any one of the preceding claims, wherein a plate heat exchanger is inclined or vertically orientated so as to cause a thermal flow of fluid when heated. 2 '5

7. The water heater as claimed in any one of the preceding claims, wherein the water / fluid path is circulated from a thermally flowing heat exchanger to and from a storage tank / vessel. -0

8. The water heater as claimed in any one of the preceding claims, wherein the water / fluid path is from a thermally flowing heat exchanger to a storage tank / vessel.

9. The water heater as claimed in any one of the preceding claims, wherein the storage tank is connected to a mains water supply -5

10. The water heater as claimed in any one of the preceding claims, wherein the burner includes a fuel valve for supplying fuel thereto and inlet vents for allowing air to enter the combustion chamber to mix with the fuel. .0

11. The water heater as claimed in any one of the preceding claims, wherein the fuel valve temperature sensor / thermostat and the delivery and return thermal flow water pipes which are connected to the thermal flow heat exchanger are positioned above the bottom section of the tank to ensure the bottom section of the tank is not heated directly by the primary combustion products and thereby remains cooler and more 5 conducive to heat recovery on the secondary combustion products which circulate through the secondary heat exchanger cavity.

12. The water heater as claimed in any one of the preceding claims, wherein the cold return pipe to the thermal flow heat exchanger entrains some of the hot water from the 60 delivery pipe from the thermal flow heat exchanger so that the temperature of the cold water in the return pipe to the heat exchanger is raised to a temperature that will stop any condensation occurring in the combustion chamber.

13. The water heater as claimed in claim 11, wherein the bottom section of the storage tank is cooled by the incoming water which occurs during any hot water draw off 65 from the top of the tank. This ensures that the bottom section of the tank is regularly cooled to improve heat transfer in the secondary heat exchanging cavity. 3

14. The water heater as claimed in any one of the preceding claims, wherein the means for circulating heat through the water heater is a combination of thermal heat rises F0 which occur in the combustion chamber, series of heat exchangers, flue duct and flue terminal.

15. The water heater as claimed in any one of the preceding claims, wherein a drain pipe collects condensation products from the base of the second heat exchanging cavity, F5 flue duct and the flue terminal and discharged them externally to the unit.

16. The water heater as claimed in any one of the preceding claims, wherein the fluid inside the storage tank is used to supply heated heating fluid to an external heating circuit, wherein a return inlet is provided in the tank for the return of the heating fluid 0 from the external heating circuit.

17. The water heater as claimed in any one of the preceding claims, wherein the eternal heating circuit is a hydronic heating circuit. 5

18. The water heater as claimed in any one of the preceding claims, can be fitted or formatted with a compressible air reservoir which is capable of absorbing the extra water volume which is caused by the water temperature rise which occurs during the heating process, and by so doing prevents the pressure in the tank from activating the pressure relief valve which saves water and energy.

19. A solar boosted water or fluid heater including a chamber; a heating means disposed within the chamber, at least one primary inclined or vertically orientated in parallel tube finned heat 95 exchanger mounted within the chamber above the heating means; a fluid inlet for supplying fluid to bottom inlet fitting of said one heat exchanger; a fluid outlet from the top of the said one heat exchanger; a flue outlet which is connected to the secondary heat exchanging cavity; an insulated storage tank which is mounted above the chamber which has a lower 00 section of the tank which is utilised as a solar heater storage reservoir and the tank is fitted with a fluid inlet and fluid outlet which is connected to an inclined or vertically 4 orientated in parallel tube finned heat exchanger which has entry points into the tank above the solar reservoir section of the tank, a fluid inlet and fluid outlet which are mounted on the tank for external connection and use, a fluid inlet and fluid outlet 5 which are mounted on the tank for connection to a solar heater, a section of the tank surface area which is utilised as a secondary combustion products heat exchanger.

20. The solar boosted water or fluid heater as claimed in claim 19, wherein the solar heater can contribute heat energy above the temperature of the gas heated top section 0 of the tank and thereby increase the storage capacity of the solar tank section to that of the entire tank volume.

21. 5