WO2020100131A1

WO2020100131A1 - Hot water tank

Info

Publication number: WO2020100131A1
Application number: PCT/IL2018/051240
Authority: WO
Inventors: Sharon Harel
Original assignee: Sharon Harel
Priority date: 2018-11-18
Filing date: 2018-11-18
Publication date: 2020-05-22

Abstract

A hot water storage tank (10) includes a water storage chamber (11) mountable in an upright orientation defining a lower end (12), a sidewall (13) and an upper end (14). The chamber has a hot water inlet connector (15) for coupling to an outlet (16) of a solar heater panel (17) and a hot water outlet connector (18) for coupling to a hot water supply in a building. The hot water inlet and outlet connectors (15, 18) are both mounted in the upper end for coupling to respective tubes (19, 20) that are external to the chamber without requiring a tube inside the chamber. In another embodiment, the tank has a single water inlet and outlet, both mounted in the base. The water outlet is coupled to a hot water outlet connector mounted in the top of the tank via a tube that is external to the tank thus avoiding cooling of the hot water as it is drawn out from the tank.

Description

Hot Water Tank

FIELD OF THE INVENTION

This invention relates to hot water tanks, particularly for solar heating systems.

BACKGROUND OF THE INVENTION

Conventional solar water heater systems comprise a solar panel connected by pipes to a hot water storage tank for thermosyphonic circulation of water. The tank has a cold water inlet for coupling to a pressurized main water supply and a hot water outlet for delivering hot water to a consumer. Typically the hot water outlet has a coupling in a flange at the base of the tank to which a feed pipe is connected and extends inside the tank toward its upper end. Water in the tank is heated either by an electric immersion heater or by solar energy and the hot water rises in close proximity to the feed pipe, thus creating a temperature gradient in the tank with the hottest water at the top and the coldest water at the base. When the hot water tap in the premises is opened, cold water from the mains supply enters the tank under pressure and urges the hot water through the feed pipe through which it descends inside the tank to the hot water outlet from where it is directed to the user premises. At the same time, the incoming cold water cools the feed pipe, which in turn cools the hot water as it descends through the tank to the hot water outlet. This may give rise to significant heat loss as hot water is drawn from the tank and, of course, it is wasteful of energy.

Many hot water tanks are formed of steel, which being metal is corrodes by the water stored therein. In order to protect against such corrosion there is commonly employed what is known as a‘sacrificial anode’ which is formed of a metal that is more reactive than steel. It is also referred to as being‘nobler’ than steel because it allows itself to corrode in order to prevent corrosion to the steel tank.

However, it has also been proposed to form the tank from non-metallic materials, which do not corrode. For example, US Patent No. 6,898,373 discloses a filament-wound pressure tank, such as those incorporated in various types of water heaters, constructed using an inner tank body which may be representatively of a blow-molded plastic construction. An electric heating element extends into the interior of the tank through a wall opening therein.

US Patent No. 5,923,819 discloses a molded polymeric fluid storage tank, and method of manufacture.

US Patent No. 4,865,220 discloses a double wall glass fiber reinforced plastic underground storage tank having an inner and outer wall between which there is an annular space.

US Patent No. 5,668,922 discloses an electric water heater whose body structure is formed from a coaxially and sealingly joined series of one-piece molded plastic body sections including opposite end sections having closed outer ends. Also disclosed are tanks that are externally insulated by wrapping the tank with an appropriate insulation material, such as fiberglass blanket insulation, and then placing a metal jacket structure outwardly around the insulation material to hold it in place and shield it from damage. Alternatively, the blanket insulation may be omitted and foam insulation injected into the space between the tank and jacket structure.

US 20160201944 discloses a water heater having a water storage chamber in an upper portion of which are fixed a water inlet for delivering unheated water into the storage chamber for heating and a water outlet for discharging heated water for use.

Thus, although it is certainly well-known to form water tanks from plastics and thereby avoid the need for a sacrificial anode and although double-wall tanks are also known, conventional hot water tanks suffer from the principal drawback that hot water is fed out of the tank via a tube that extends through the inside of the tank and is thereby cooled during its exit.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a hot water tank that overcomes this limitation.

This object is realized in accordance with the invention by a hot water tank having the features of the independent claims. BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 is a sectional view through a longitudinal axis of a hot water storage tank according to an embodiment of the invention;

Fig. 2 is a perspective view showing an internal detail of the tank;

Figs. 3 and 4 show in perspective respective plan and base views of the tank;

Fig. 5 is a perspective view showing a further internal detail of the tank and external connection of an immersion heater;

Fig. 6 is a sectional view of the tank through the base;

Fig. 7 shows an enlarged detail of the cold water inlet and the immersion heater;

Fig. 8a shows an embodiment of the water tank connected to a solar panel;

Fig. 8b is an enlarged detail showing connection of the water tank to the cold water inlet of the solar panel;

Fig. 9a shows connection of the cold water inlet pipe and of the cold water outlet pipe to the tank;

Fig. 9b is an enlarged detail of a threaded connector fixed to the cold water inlet and to the cold water outlet for external coupling thereto; and

Fig. 9c is an exploded view showing a detail of the threaded connector and a mounting plate for securing to the base of the tank.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to the figures there is shown a hot water storage tank 10 for a solar heating system. The tank 10 comprises a water storage chamber 11 configured for mounting in an upright orientation as shown in Figs. 1, 2 and 5 defining a lower end 12, a sidewall 13 and an upper end 14. The chamber 11 has a hot water inlet connector 15 for coupling to an outlet 16 of a solar panel 17 (shown in Fig. 8 a) and a hot water outlet connector 18 for coupling to a hot water supply (not shown) in a building. The hot water inlet connector 15 and the hot water outlet connector 18 are both mounted in the upper end 14 for coupling to respective tubes 19 and 20 that are external to the chamber. As best seen in Fig. 1, an outer jacket 21 surrounds at least the sidewall 13 of the chamber 11 thereby defining between an inner wall surface of the jacket and an outer wall surface of the chamber an air gap 22, which may be filled with thermally insulating material such as polyurethane 23. The hot water inlet connector 15 and the hot water outlet connector 18 are respectively coupled via the tubes 19 and 20 to a hot water outlet 24 and a hot water inlet 25 both mounted toward the lower end of the chamber. Preferably, the outer jacket 21 is a domed vessel that surrounds the chamber and conceals the tubes 19 and 20, which extend along the upper end 14 and down the sides of the chamber, where they are respectively connected to the hot water outlet 24 and the hot water inlet 25 mounted in a base 28 of the tank fixed to a lower rim of the outer jacket 21.

Preferably, as shown in Figs. 4 and 5, a cold water inlet 29 is mounted in the base 28 and is adapted for connection to a main water supply. Likewise, a cold water outlet 30 mounted in the base is adapted for connection to an inlet 31 of the solar panel 16 (shown in Fig. 8b). In a preferred embodiment, the cold water inlet 29 and the cold water outlet 30 comprise respective pipes 32 and 33 that are integrally molded with the chamber 11 and are anchored to respective couplers 34 shown in Fig. 9a that are fixedly supported on the base 28. The couplers 34 include internal threads 35 to which external pipes 36 can be threadably attached via connectors 37 in known manner. Tightening the connectors 37 requires significant torque, which if applied unchecked to the couplers 34 would possibly rupture the pipes 32 where they are attached to the chamber 11. To prevent this from happening, the couplers 34 are supported by faceplates 38 that are anchored to the base 28 and have hexagonal apertures 39 that accommodate the hexa gonal body of the couplers 34 and prevent them from rotating.

Referring to Fig. 7, it is seen that the pipe 32 of the cold water inlet 29 protrudes slightly inside the chamber 11. The end 40 of the pipe is sealed, an exit aperture 41 being formed in a sidewall of the pipe 32 from which cold water entering the pipe 32 under pressure exits so that it circulates toward the lower end of the chamber. This avoids the problem associated with conventional inlet pipes where cold water is forced upward under pressure so that it rises toward the hotter water, which cooled by the incoming cold water. An electrical immersion heater element 42 may be removably mounted in the sidewall 13 via a junction box 43 that is affixed to the outer wall surface of the jacket and from which a flexible conduit 44 may convey electrical connections to the base.

Preferably, the chamber 11 is formed of reinforced plastics, which as well as being light, avoids the need for a sacrificial anode. The reinforcement may be by means of fiberglass or carbon fibers which can be molded integrally with the chamber. Additionally or alternatively, the chamber may be covered with a fiberglass or carbon fiber coating.

Such an arrangement offers a number of advantages over hitherto-proposed water tanks. First, the two hot water connections are mounted at the top of the tank, where the water is hottest, since hot water rises. Secondly, and most importantly, the hot water outlet connector is coupled to the hot water outlet at the base of the tank via a tube that is external to the tank and is therefore not subject to cooling via the cold water in the tank, which replenishes the hot water as it is drawn out of the tank. Thirdly, since the tube is preferably enclosed within the air gap between the water storage chamber and the outer jacket and since the air gap is preferably filled with thermally insulating material, the hot water fed from the hot water outlet connector at the top of the tank reaches the hot water outlet at the base of the tank with substantially no loss in temperature. This translates to a significant saving in energy over time, particularly when the hot water is heated electrically. Furthermore, having the two water inlets and the two water outlets mounted in and therefore accessible from the base of the tank, facilitates connection to the tank. This is of particular benefit when the tank is part of a thermosyphonic solar system, which requires the tank to be mounted higher than the solar panel so that the water heated by the solar panel rises owing to its decreased density. In such systems, the tank is mounted on the roof of a building and the easy access to the connections from the base of the tank facilitates coupling to the solar panel.

The hot water storage tank has been described with particular reference to a solar heating system wherein the cold water outlet 30 is connected to an inlet of the solar panel and the hot water inlet 25 is coupled to an outlet of the solar panel and hot water inlet 25. The solar panel thus receives cold water from the hot water storage tank and returns hot water back to the hot water storage tank. However, many of the benefits of the invention are equally applicable to hot water storage tanks adapted for non-solar applications. Such a tank may be identical to that described above except for the fact that it requires only a single water inlet and a single water outlet, both of which are mounted in the base. The water inlet is adapted for connection to the mains water supply and the water outlet is adapted for connection to the hot water supply in the user’s premises and is coupled to a hot water outlet connector mounted in the top of the tank via a tube that is external to the tank and thus avoids cooling of the hot water as it is drawn out from the tank.

In accordance in with this embodiment, there is thus provided a hot water storage tank, comprising

a water storage chamber configured for mounting in an upright orientation defining a lower end, a sidewall and an upper end of the chamber,

an outer jacket surrounding at least the sidewall of the chamber and defining an air gap between an inner wall surface of the jacket and an outer wall surface of the chamber,

a hot water outlet mounted toward the lower end of the chamber, and a hot water connector mounted in said upper end and coupled to the hot water outlet via a tube extending through the air gap.

All other details are the same as for the embodiment described above and may include insulating material in the air gap and an electrical immersion heater element removably mounted in the sidewall. The chamber may likewise be formed of plastics thus avoiding the need for a sacrificial anode.

It will be understood that changes may readily be made to the hot water tank without departing from the scope of the appended claims. For example, the cold water inlet and outlet pipes do not need to integrally molded with the chamber and the couplers may be prevented from rotating relative to the inlet and outlet pipes other than the specific faceplate as shown in the figures. Clearly, the couplers do not need to have a hexagonal body or the faceplates hexagonal apertures.

Claims

CLAIMS:

1. A hot water storage tank for a solar heating system, said hot water storage tank comprising:

a water storage chamber configured for mounting in an upright orientation defining a lower end, a sidewall and an upper end of the chamber, said chamber having a hot water inlet connector for coupling to an outlet of a solar heater panel and a hot water outlet connector for coupling to a hot water supply in a premises;

said hot water inlet connector and said hot water outlet connector both being mounted in said upper end for coupling to respective tubes that are external to the chamber without requiring a tube inside the chamber.

2. The hot water storage tank according to claim 1, further including an outer jacket surrounding at least the sidewall of the chamber and defining an air gap between an inner wall surface of the jacket and an outer wall surface of the chamber.

3. The hot water storage tank according to claim 2, wherein the hot water inlet connector and the hot water outlet connector are respectively coupled via said tubes to a hot water outlet and a hot water inlet both mounted toward the lower end of the chamber.

4. The hot water storage tank according to claim 3, further including a base in which the hot water outlet and the hot water inlet are mounted.

5. The hot water storage tank according to claim 4, wherein there are further mounted in the base a cold water inlet and a cold water outlet, the cold water inlet being adapted for connection to a main water supply and the cold water outlet being adapted for connection to an inlet of the solar panel.

6. The hot water storage tank according to claim 5, wherein the cold water inlet includes a pipe that protrudes inside the chamber and terminates in a sealed end, there being an exit aperture formed in a sidewall of the pipe.

7. The hot water storage tank according to claim 5 or 6, wherein the water storage chamber is formed of molded plastics and the cold water inlet and the cold water outlet are integrally molded with the chamber.

8. The hot water storage tank according to claim 7, wherein the cold water inlet and the cold water outlet comprise respective pipes that are integrally molded with the chamber and are anchored to respective couplers that are fixedly supported on the base.

9. The hot water storage tank according to claim 8, wherein the couplers are configured for threaded attachment to external pipe connectors and are supported by faceplates that are anchored to the base and prevent the couplers from rotating.

10. The hot water storage tank according to any one of claims 3 to 9, wherein the base is fixed to a lower rim of the outer jacket.

11. The hot water storage tank according to any one of claims 2 to 10, further including thermally insulating material in the air gap.

12. A hot water storage tank, comprising:

13. The hot water storage tank according to claim 12, wherein a lower rim of the outer jacket is fixed to a base in which the hot water outlet is mounted.

14. The hot water storage tank according to claim 13, wherein there is further mounted in the base a cold water inlet adapted for connection to a main water supply.

15. The hot water storage tank according to claim 14, wherein the cold water inlet includes a pipe that protrudes inside the chamber and terminates in a sealed end, there being an exit aperture formed in a sidewall of the pipe.

16. The hot water storage tank according to claim 14 or 15, wherein the water storage chamber is formed of molded plastics integrally molded with the cold water inlet.

17. The hot water storage tank according to claim 16, wherein the cold water inlet includes a pipe that is integrally molded with the chamber and is anchored to a coupler that is fixedly supported on the base.

18. The hot water storage tank according to claim 17, wherein the coupler is configured for threaded attachment to an external pipe connector and is supported by a faceplate that is anchored to the base and prevents the coupler from rotating.

19. The hot water storage tank according to any one of claims 12 to 18, further including thermally insulating material in the air gap.

20. The hot water storage tank according to any one of the preceding claims having an electrical immersion heater element removably mounted in said sidewall.

21. The hot water storage tank according to any one of the preceding claims, wherein the water storage chamber is formed of plastics.