This invention relates to a solar electric power generator. BACKGROUND ART There are a few types of sun light concentrators and converters to produce electricity from solar energy.

Sunlight concentrators

Glass lenses focus sun light very well and they are long-lasting, but expensive to manufacture. Cheap plastic lenses are inexpensive, but not long lasting due to gradual degradation of plastic. Parabolic concentrators are quite expensive because of mechanical and optical requirement such as an accurate shape, fine polishing and reflecting capabilities. Unfortunately, all these devices have one basic problem: they require some systems to track and adjust to the sun's position to extract maximum of energy. If not, their performance decreases with the decrease of incident angle of sun lights.

Therefore, they are unable produce a lot of very hot water or hot air needed for some domestic or industrial needs.

Traditionally, solar heaters are used to heat water. Typically, they use lenses, such as disclosed in Ref [1] or parabolic concentrators. The majority of domestic heaters have a plane shape like in Ref [2]. Just a few models have semi-spherical shape like in Ref [3], where a semi-sphere filled with water used to absorb heat with absorbing material at the bottom.

Some of these models include dark absorbing particles like those disclosed in Ref [4]. The applicant has found just a few spherical systems. One of those in Ref [5] uses and absorbing ball heated by a set of spaced focusing lenses.

Another one in Ref [6] uses a bladder ball. However, the bladder doesn't play the role of a lens and has no collector having a spherical top surface.

The prior art systems can't produce a lot of very hot water needed for some domestic applications (to warm a spa, for example) and industrial applications like milk pasteurisation or methanol/spirit extraction from organic materials.

For example, High Temperature Shot Time (HTST) pasteurization requires 78C, Ultra High Temperature (UHT) pasteurization is being conducted at 89 to 100 C depending on time of exposure. Dry milk power production requires similar temperatures. Methanol /sprits extraction from water solutions is being kept at 60- 9OC, depending on type of production.

Electric power generators

A commonly used approach is to

(1) to heat water and produce very hot steam (~400C) using various types of sunlight concentrators and (2) then to inject this steam into a gas turbine to generate electricity. However, there are many places on our planet, deserts for example, where is a very little water or no water at all. Just a few models use hot air to produce electricity like in Ref [7]. There, hot air is used in combination with a water injector to spin a wheel. This is very different from our device. Another example is Ref [8], where a turbine is used to receive heated air, produce rotary motion and to convert the rotary motion into electric power. As for direct solar energy convertors to produce electricity, silicon panels for example, they are still too expensive to be widely used commercially. The cost of solar energy is too high as compared with traditional carbon or gas power stations producing CO2. The extraction coefficient (ratio electric power to sun radiation power) is quite low for solar panels. The best panels can achieve just 10% of such the conversion.

The applicant offers a very simple idea to derive electrical energy from the sun's radiation. It seems to be cost effective, and is at least compatible with the best solar panels or significantly cheaper.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

DISCLOSURE OF INVENTION The Solar Electric Power Generator includes a solar air heating module and a hot air engine.

The solar air heating module consists of a transparent glass or plastic spherical ball filled with water (it is the only place where water is used) or another transparent liquid. The ball is suspended over a metal container absorbing the sunlight and thus its heat. Herewith, the ball plays the role of a lens.

The main requirement is that the container has to have a substantially spherical upper surface. This upper surface should be understood to mean the sunlight contact surface.

The centre of curvature of this sunlight contact surface should be substantially coincident with the ball's centre. The distance between the ball and the container's surface should be the same and adjusted in such the way as to achieve maximum sun energy concentration on the focused sunspot.

The main advantage of this system is that it doesn't require tracking and adjusting to the sun's position. This is done automatically due to the geometry/symmetry of the system. The container should be oriented in such a way as to keep the daily trajectory of the sun focused spot on its surface.

Hot pressurised air produced in the container is then supplied to the engine to generate electricity. The applicant has measured the temperature of this hot air and found that it can easily reach 300C and higher. This means that pressure in the container can be at least twice higher than atmospheric.

The fully symmetrical container can be trimmed to reduce cost of manufacturing. However, the main requirements remain the same: • the centre of curvature of the top of the container's surface should be substantially coincident with the ball's centre;

• the distance between the ball and the container's surface should be the same and adjusted in such a way to achieve maximal sun energy concentration on the focused light spot; • the trimmed container may be oriented in such the way to keep the sun's focussed spot on its surface for the whole year. Then, it will not require the tracking system or further adjustment to the sun's position.

In an alternative embodiment of the present invention, the fully symmetrical container may be replaced by a curved pipe. In this embodiment, the main requirements are:

• the centre of curvature of that pipe should be substantially coincident with the ball's centre;

• distance between the ball and the pipe should be the same and adjusted in such the way to achieve maximal sun energy concentration on the focused light spot;

• the pipe may be oriented in such the way to keep the sun's focussed spot on its surface for the whole day according to the sun's daily trajectory. This will not require the tracking system. But, it will require just a small daily adjustment (or, once in a few days) to fit the sunspot's trajectory. The container may be built in various modifications.

However, the main requirement remains the same: centre of curvature of the top container's surface should coincide with the ball's centre. Distance between the ball and the container's surface should be the same and adjusted in such a way as to achieve maximal sun energy concentration on the focused light spot. The container should be oriented in such a way as to keep the daily trajectory of the sun focused spot on its surface.

The hot air engine may include (a) a cylinder, (b) a piston coupled with (c) permanent magnet through (d) a pushrod, (c) a spring, which is being contracted, when the piston is moving upwards and expanded, when the piston is moving downwards, (e) inlet and (T) outlet valves, (g) an external coil, in which electric current is generated due to induction when the permanent magnet begins to oscillate. It should be appreciated that the magnet-coil system presents a linear generator. Persons skilled in the art will appreciate that the hot air engine may be modified according to the requirements of the user, and such modifications are not outside the scope of the present invention.

The main advantages of this system are:

• The glass or plastic ball is put symmetrically above the surface of the container. Because of this, it may not require a tracking system to compensate for the movement of the sun.

• The ball is cheap to manufacture and doesn't require expensive optical equipment to make a suitable lens or refractor. It does not need to be perfectly symmetrical.

• Water has refractive index 1.33, which is similar to glass (1.4 for Pyrex, 1.49 for Acrylic glass, 1.52 for Crown glass, 1.488 for Plexiglas, etc) and focuses sun light into a very small hot spot. For example, diameter of the spot (see Fig 1) is just a couple of mm for a ball of diameter 20 cm.

The Solar Electric Power Generator is designed for the Earth's regions which receives a lot of sun, but has very little or no water (deserts, for example). It doesn't use steam or gas turbines and doesn't produce any carbon dioxide. Thus, it is an environmentally friendly method of generating electricity.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

BRIEF DESCRIPTION OF THE DRAWINGS Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

FIG 1 is a perspective view of the solar air heating module in accordance with the present invention. FIG 2 is a side view of the hot air engine using the solar air heating module in accordance with the invention.

FIG 3 illustrates Step 1 of the present invention's operation. FIG 4 illustrates Step 2 of the present invention's operation. FIG 5 illustrates Step 3 of the present invention's operation. FIG 6 is a side view of the solar heating module in a frame assembly in accordance with the invention. FIG 7 shows a side view of a plurality of solar heating modules in a frame assembly in accordance with the invention.

FIG 8 is a view of the solar heating module with an insulation system to prevent thermal losses in accordance with the invention. FIG 9 is a view of an alternative embodiment of the solar heating module in accordance with the invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Figure 1 is a perspective view of the solar air heating module (generally indicated by arrow 1) in accordance with the invention. 2 is a spherical lens, 3 is metal container, 4 is module's outlet pipe, 5 is module's inlet pipe, 6 is focused sunspot and 7 is the line of the focused spot's daily trajectory.

The spherical lens (2) focuses the solar rays (20) into the focused sunspot (6) which heats the interior (not shown) of the container (3).

Figure 2 is a side view of the hot air engine (8) using the solar air heating module (not shown) in accordance with the invention. 9 is the cylinder, 10 is the piston, 11 is the spring, 12 is engine's inlet valve, 13 is engine's outlet valve, 14 is engine's inlet pipe, 15 is engine's outlet pipe, 16 is permanent magnet, 17 is induction coil and 18 is pushrod.

Figure 3 presents Step 1 of the engine's (8) operation. The valves (12, 19) of the engine (8) and solar air heating module (1) respectively are closed and valve (13) is open.

The solar rays (20) are focused by the spherical lens (2) onto the container (3). This results in air (not shown) being heated inside the container (3) until its temperature and pressure reaches its maximum. 9 is the cylinder, 10 is the piston, 11 is the spring, 12 is engine's inlet valve, 13 is engine's outlet valve, 14 is engine's inlet pipe, 15 is engine's outlet pipe, 16 is permanent magnet, 17 is induction coil, 18 is pushrod and 19 is the container's (3) inlet valve.

Figure 4 presents Step 2 of the engine's (8) operation. When the temperature and pressure of the air (not shown) inside the container (3) reaches its maximum, valves (19, 13) are closed and valve (12) opens. Hot air is injected (arrow 21) into the cylinder (9) and pushes piston (10) and magnet (16) upwards, compressing the spring (11).

Figure 5 presents Step 3 of the engine's (8) operation. When the magnet (16) reaches its maximum position and the spring (11) is fully compressed, valve (12) is closed, while valves (13) and (19) open. Hot air (not shown) escapes outside through the outlet pipe (15).

Both piston (10) and magnet (16) fall down under gravity and starts to oscillate creating electric current in coil (17) due to induction. The rest of the hot air (not shown) in the container (3) goes outside through valve (19) and pressure inside the container (3) comes to equilibrium with outside pressure.

Then, Steps 1 , 2 and 3 are repeated and so on.

The spherical lens (2) may be mounted in a frame assembly (22) as depicted in Figure 6. The container (3), with an inlet (4) and outlet (5) is also secured in the frame (22). This forms a frame assembly (23)

A number of these frame assemblies (23) may integrated into a module (24), as depicted in Figure 7. Each assembly (23) has pipes (25, 26) connecting the various inlets (4) and outlets (5) of each container (3). Figure 8 is a view of the solar heating module (1) with an insulation system to prevent thermal losses from the container (3). 27 is top glass cover creating air gap (28) between the container (3) and cover (27). 29 are insulating panels.

The container may be refined as necessary to reduce fabrication costs. An alternative embodiment of the container (30) is illustrated in Figure 9, in which the fully symmetrical container (not shown) is replaced by a curved pipe (30).

2 is spherical lens filled with water (32), 30 is the curved pipe, 5 is inlet, 4 is outlet, 6 is focused sunspot. The daily trajectory of the sunspot (6) is in line with the curved pipe (30). Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

REFERENCES

1. US Patent 6,763,826, July 20, 2004, Gumm , et al, Solar water heater. 2. US patent 6,526,965 B1 , Mar 4, 2003, Clyde W. Devore, Solar Energy Collection Panel for heating pools of water.

3. US Patent 4,537,180, Aug 27, 1985, John W. Minor, Solar Heating and Storage Unit.

4. US Patent 6,082,354, JuI 4, 2000, John Rekstad, Solar Collector.

5. US Patent 4,327,552, May 4, 1982, Joseph Dukess, Solar Heat Apparatus.

6. US Patent 4,690,128, Sep 1 , 1987, Carl B. Gibbons, Insulated Flexible Bladder Solar Collector.

7. US Patent 7,481 ,057, Jan 27, 2009, Patwardhan, Niket Keshav, Low cost solar energy extraction.

8. US Patent 7,325,401 , February 5, 2008, Kesseli; James B., Wolf; Thomas L.,

Power conversion systems.