WO2010071903A2

WO2010071903A2 - Solar geysers

Info

Publication number: WO2010071903A2
Application number: PCT/ZA2009/000102
Authority: WO
Inventors: Sven Ian Jacobsen
Original assignee: Sven Ian Jacobsen
Priority date: 2008-11-17
Filing date: 2009-11-17
Publication date: 2010-06-24
Also published as: WO2010071903A3; AU2009327343A1; ZA201104435B; AP2011005759A0

Abstract

A solar geyser (10), especially for use in parts of the word with high levels of solar radiation, the geyser comprising a spherical container (12) housed within a translucent shell (14) and a vacuum providing insulation between the shell and the container. The container being painted black to ensure maximum absorption of solar radiation, and the geyser including an inner reservoir (30) for storage of warm water (16) and means for monitoring the heat of the water in the inner reservoir - if the temperature reaches a predetermined maximum more water is added to the outer tank. If a predetermined minimum temperature is reached the flow of water into the outer container will be interrupted to ensure that the available water reaches the desired temperature.

Description

SOLAR GEYSERS

TECHNICAL FIELD OF THE INVENTION

This invention relates to solar geysers.

BACKGROUND ART

The climate change linked to excessive Green House gas emissions presents very serious global risks, and demands an urgent response. The energy generating industry is responsible for an estimated 24% of all emissions on a global scale.

Electrical demand is escalating and it is estimated that domestic electricity consumption constitutes at least 18% of the total used in South Africa.

One of the most effective ways to reduce the electrical demand is the mass application of Solar Water Heating systems.

These types of heating systems conventionally consist of a Solar Heater Gathering Panel or Solar Heating Gathering Tubes (which are sometimes incorporated in a low pressure or a vacuum) and an insulated water tank to hold the heated water.

Many of these solar water heating systems or geysers have limited efficiencies due to a flat surface area which has to be installed at a specific angle and direction to allow for an average optimum sunlight angle to fall on them. The angle of sunlight changes throughout the day and year i.e. early morning through to late afternoon and summer through to winter.

The heating of the water is achieved by the gathering panels or tubes transferring this heated water to the insulated Water Tank. In some the prior art other liquids (Ethylene Glycol for e.g.) are heated in the panels and tubes and then through the use of a heat exchanger system transfers the solar heat into the water which is then kept in the insulated water tank. A principle disadvantage associated with the manufacturing of the above heaters is the amount of materials, labour and energy used to produce them for the heating, storing and insulating of the heated water.

It is the object of this invention to provide a solar water heater which is more cost effective and simpler to construct and install than those described above.

DISCLOSURE OF THE INVENTION

According to the invention a solar geyser consists of a container for liquid housed within a translucent shell, the container including an inner reservoir; the container and the shell being held in a spaced apart relationship; the area between the shell and the container comprising a zone of reduced pressure; the container being heated by solar radiation which in turn heats the liquid by conduction, the heated liquid being diverted to and stored in the reservoir.

The area between the shell and the container may comprise a vacuum to act as an insulator to ensure the minimum heat loss.

In the preferred form of the invention the container is spherical to maximise exposure to solar radiation.

The arrangement may further include an insulation tube around the extraction pipe to ensure minimal heat loss. The tube may include a vacuum for this purpose.

The vacuum zone between the container and the translucent shell may include an outlet to maintain the vacuum or to seal it.

In the preferred form of the invention this outlet includes a gauge to monitor the vacuum.

The reservoir may comprise a further tank that may be incorporated at the centre of the above arrangement in order to facilitate storage of heated water. In this form of the invention the geyser includes means for measuring the temperature of the stored water. The means may be connected to a regulator which allows water to flow into the tank if the temperature reaches a predetermined maximum, or to interrupt the flow of water if the temperature reaches a predetermined minimum. In the preferred form of the invention the container is filled with water, but in an alternative form of the invention the tank is filled with a liquid which has a higher boiling point than water, for example ethylene glycol. In this form the geyser includes a tube which passes through the liquid and through which water passes, cold water entering at the beginning of the tube and warmed water exiting at the other end.

The water may be heated through the tube by the warm surrounding liquid. The tube may be in a spiral form to ensure the maximum heat exposure of the water.

In the preferred form of the invention the geyser is placed on a pole or the like at a point higher than where the warm water is supplied, thus using gravitational forced to distribute the warm water. This system may be adapted to include a pump if necessary.

The shell may comprise glass or reinforced methyl methacrylate while the container may comprise metal - preferably stainless steel.

The container may be painted black to attract the maximum solar radiation and may include a plumbing arrangement adapted to extract warm liquid from the upper part of the container while unheated liquid is introduced from the bottom of the container.

An electrical booster or element may be added to the tank to substitute solar energy if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is described below with reference to the accompanying drawings in which:

Figure 1 is a sectional side view of a solar geyser according to the invention; And Figure 2 is a similar view of an alternative form of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawing a spherical geyser 10 comprises a container 12 and a translucent outer shell 14. The container is painted in a dark colour, preferably black, in order to attract the most solar energy.

The container is filled with water 16 which is replenished from a source 18 near the bottom 20 of the tank. Heated or warm water is extracted through an outlet 22 near the top 24 of the tank.

Heated water 28 cascades into an inner reservoir 30 from where warmed water is extracted through a downwardly depending pipe 31.

The geyser further includes a vacuum zone 26 between the tank and the shell. The zone acts as a heat insulator. The conduit is located near the top of the tank to make manufacturing thereof easier.

The vacuum is maintained through an outlet 32 which includes a valve 34 and a gauge (not shown).

The geyser also includes an overflow (not shown).

In use the geyser is mounted on a pole 40 or the like. Solar radiation passes through the translucent shell and heats the black surface of the tank - which in turn heats the water within the tank. The vacuums ensure the minimum possible heat loss.

Heated water rises to the top of the spherical tank and is extracted by a pipe close to the top, ensuring the warmest water is extracted first. The heated water is stored in the inner reservoir until it is extracted for use.

Electric means (not shown) is provided for monitoring the heat of the water in the inner reservoir — if the temperature reaches a predetermined maximum more water is added to the outer tank. If a predetermined minimum temperature is reached the flow of water into the outer container will be interrupted to ensure that the available water reaches the desired temperature. The shape of the tank is important to ensure maximum exposure to direct sunlight during the day, irrespective of the angle at which it is installed.

In Figure 2 an inner tank 50 is provided and filled partially with a liquid 51 (preferably water) in order to ensure a pneumatic pressure rather than a hydraulic pressure is provided.

Entrapped air (or gas) 52 compresses in this inner expansion tank to take up the expansion of the liquid 56 as the temperature rises, thus creating a pneumatic pressure and not a hydraulic pressure, which also acts as a shock absorber.

In this figure a heat exchange system is provided in the tank which includes a spiral tube 52 through which water 54 passes. The tube is located within the tank which is filled with ethylene glycol 58 in this form of the invention. Solar energy heats the ethylene glycol in a similar fashion as in figure 1 , and the heat is transferred to the water within the heat conductive tube.

Claims

CLAIMS:

1. A solar geyser (10) characterised in that it consists of a container (12) for liquid (16) housed within a translucent shell (14), the container including an inner reservoir (30); the container and the shell being held in a spaced apart relationship; the area between the shell and the container (26) comprising a zone of reduced pressure; the container being heated by solar radiation which in turn heats the liquid by conduction, the heated liquid (28) being diverted to and stored in the reservoir.

2. A solar geyser according to claim 1 characterised in that area between the shell and the container (26) comprises a vacuum.

3. A solar geyser according to claims 1 or 2 characterised in that the container (12) is spherical.

4. A solar geyser according to any of claims 1 to 3 characterised in that the geyser includes an insulation tube creating a vacuum around an extraction pipe.

5. A solar geyser according to any of claims 1 to 4 characterised in that the vacuum between the container and shell includes an outlet (32) to maintain the vacuum and to seal it.

6. A solar geyser according to claim 5 characterised in that the outlet includes a gauge to monitor the vacuum.

7. A solar geyser according to any of claims 1 to 6 characterised in that the reservoir comprises a further tank (30) which is incorporated at the centre of the container.

8. A solar geyser according to claim 7 characterised in that the container and the tank are filled with water (16)

9. A solar geyser according to any of claims 1 to 8 characterised in that the means is provided for measuring the temperature of the stored water; the means being connected to a regulator which allows water to flow into the tank if the temperature reaches a predetermined maximum, or to interrupt the flow of water if the temperature reaches a predetermined minimum.

10. A solar geyser according to any of claims 1 to 6 characterised in that the container is filled with a liquid (58) which has a higher boiling point than water and a tube (52) is provided which passes through the liquid and through which water (54) passes, cold water entering at the beginning (18) of the tube and warmed water exiting at the other end.

11. A solar geyser according to claim 10 characterised in that the liquid is ethylene glycol.

12. A solar geyser according to claims 10 or 11 characterised in that the tube (52) is in a spiral form within the spherical container (12).

13. A solar geyser according to any of claims 1 to 12 characterised in that the geyser is placed on a pole (40) at a point higher than where the warm water is supplied.

14. A solar geyser according to any of claims 1 to 12 characterised in that the geyser is adapted to include a pump.

15. A solar geyser according to any of claims 1 to 14 characterised in that the shell (14) comprises reinforced methyl methacrylate and the container (12) comprises stainless steel.

16. A solar geyser according to any of claims 1 to 15 characterised in that the container is black

17. A solar geyser according to any of claims 1 to 16 characterised in that the container includes a plumbing arrangement adapted to extract warm liquid from the upper part (24) of the container while unheated liquid is introduced from the bottom (20) of the container.

18. A solar geyser according to any of claims 1 to 17 characterised in that an electrical booster or element is provided to substitute solar energy if required.