AU2012201047B2

AU2012201047B2 - Solar cooking appliances

Info

Publication number: AU2012201047B2
Application number: AU2012201047A
Authority: AU
Inventors: Huazi Lin
Original assignee: W&E International Canada Corp
Current assignee: W&E International Canada Corp
Priority date: 2009-07-23
Filing date: 2012-02-23
Publication date: 2014-06-05
Anticipated expiration: 2030-07-19
Also published as: AU2012201047A1

Abstract

A solar cooking appliance comprising a solar heat collector to collect and store solar heat, a heat storage and conducting material partially filling said solar heat collector and a set of solar cooking utensils, where each utensil is sized to fit a shape and size of the internal shape and size of the solar heat collector. The utensil has a wall which is heatingly connected to the heat storage and conducting material and an internal wall of the solar heat collector to receive solar heat for cooking food. The utensil further comprises a removable part for opening and closing said utensils during cooking. m . . . . . . .

Description

pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Solar cooking appliances The following statement is a full description of this invention, including the best method of performing it known to us: P11 1AHAU/0710 SOLAR COOKING APPLIANCES FIELD OF TECHNOLOGY The present disclosure relates to solar heat application field, especially related to solar cooking appliances to cook the food in the solar heat collector. BACKGROUND [0002] For all kinds of existing energy sources in the earth, solar energy is the most widespread, the richest and the most uniformly distributed energy source. Solar energy can be used very easily. It is available every day, everywhere and for every body. 10003] For all kinds of human energy consuming activities, cooking food and beverage is the most often activity and has the longest history. Every body in anywhere needs to cook the foods every day. [00041 It is very interesting and valuable topic to use solar energy for food cooking. There are many efforts in this field. (Please refer to the existing patents). [00051 The solar power on a unit earth area is not very large. The solar radiation intensity is varied from North to South and from morning to afternoon. It depends on the weather and is also different in four seasons, so that to develop an economic solar cooking appliance is always a challenge and need continue efforts. [00051 In view of these difficulties, some solar cooking appliances tried to make the sunlight receiving area as large as possible. But the heat insulation for the received heat is difficult. Some solar cooking appliances follow and focus the sunlight using expensive automation system and need additional power to run the system. Some solar cooking appliances also use the heat storage materials. The materials may be expensive and not easy to get. [0006] Therefore, it is an important topic for the industry to further develop and improve applications of the solar cooking technology to develop a set of economic and practicable solar cooking appliances. SUMMARY 10007] The object of this disclosure is to improve the existing technologies and provide a solar cooking appliance that is economy, easy to manufacture and use and high efficient. The invention in various embodiments takes following optional steps to overcome the difficulties of applying solar energy for food cooking: [0008] To use the evacuated solar heat collector for optimum heat collecting; 1 [0009] To fill solid heat storage and conducting material in the evacuated solar heat collector for storing and saving heat. It not only to provide a continue and stable cooking heat, but also to provide a cookingtemperature higher than the water boiling and steam temperature for more cooking purposes. To use second heat conducting/transferring material to transfer the heat faster from solar heat collector to solar cooking utensil; [09101 A light reflector focuses the surrounding light to the cooking appliances; [00111 A sundial indicates the light direction, an adjustable and rotatable fixing and supporting trestle allows to receiving the highest solar power; 100121 An electric power supply provides a backup power source when the solar power is not enough. Further more, the solar cooking appliances also provide backup heat source or energy storage equipment at low electricity price period for cooking at electric power outage. [00131 Following are the detailed summary of present disclosure. [00141 In accordance with one aspect of the present disclosure there is provided a solar cooking appliance, comprising: a tubular solar heat collector to collect and store solar heat, having: a heat storage and conducting material partially filling said solar heat collector, wherein said solar heat collector can heat said first heat storage and conducting material; a solar cooking utensil removably locatable within the solar heat collector, wherein said solar cooking utensil is sized to fit a size and shape of the internal size and shape of the solar heat collector, and said utensil having a wall which is thermally connected to the internal wall of the solar heat collector and the first heat storage and conducting material to transfer heat to the utensil, and said utensil having a removable part for opening and closing said utensil; and a removable part to cover the top of the tubular solar collector. [0014b] Preferably, a second heat conducting/transferring material is located within said solar heat collector and thennally connected said first heat storage and conducting material for faster transferring the solar heat to said cooking utensil, wherein said second heat conducting/transferring material is selected from a group of: a heat tube, a metal conductor, an alloy conductor and a heat conductive conductor able faster transferring heat, and the necessary accessories that including a fixing and supporting trestle with a rotatable base and adjustable incidence angle that arrange and support the each part of the solar cooking appliances at a proper situation; the light reflecting object and a cone bar attached to the solar heat collector perpendicularly to show the angle of sun light. [0015] Preferably, the said solar heat collector is a evacuated-tube solar heat collector; or a group of modular evacuated-tube solar heat collectors that mounted in a certain shape, e.g. in parallel row, in full or partial cone-shaped column, etc; the said heat storage and conducting material can be a solid material, or a liquid material or a chemical or change head storage materials, or the combination of two or more materials mentioned above. The said heat conducting material can be a heat tube, or a heat conductor. For 2 safety reason, transparent cover or evacuated toughened-glass tube solar heat collector are suggested. [00161 In accordance with another aspect of the present disclosure there is provided a set of solar cooking utensils, each of said utensil is a cylinder container made of stainless steel, that is located in an evacuated-tube solar heat collector, having a removable and detachable handle at the inner wall; said container having a diameter near but not bigger than the inner diameter of said evacuated-tube solar heat collector; a pleated structure on the wall of said container from the top to the bottom to provide a gap and patch for air exchange and allow a minor adjustable diameter for said container. These utensils can be a solar coffee/tea maker, a steamer, a solar cooking fryer; a cooking wok or pot, a boiler, a cooking pan etc. [0017] In accordance with another aspect of the present disclosure there is provided a set of solar cooking appliances that mainly use the solar heat, but use electricity as a backup, comprising, a solar heat collector to collect and store solar heat; a first solid heat storage and conducting material partially filling said solar heat collector, wherein said solar heat collector can heat said first solid heat storage and conducting material to a temperature higher than the water boiling temperature; a solar cooking utensil located within the solar heat collector, wherein said solar cooking utensil is sized to fit a size and shape of the internal size and shape of the solar heat collector, and said utensil having a wall which is thermally connected to the internal wall of the solar heat collector and the first solid heat storage and conducting material to transfer heat to the utensil, and said utensil having a removable part for opening and closing said utensil; and an electric heater providing a back up of heating source and electric heat storage, comprising: an electric heating element located under the solar cooking utensil and within said first solid heat storage and conducting material; and the necessary accessories that including a fixing and supporting trestle with a rotatable base and adjustable incidence angle that arrange and support the each part of the solar cooking appliances at a proper situation; the light reflecting object and a cone bar attached to the solar heat collector perpendicularly to show the angle of sun light; a electric heat element with power supply and a measuring, indication and controlling systems for the solar cooking appliance's operating characteristic parameter, e.g. timing, temperature, pressure, moisture etc. [0018] Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DISCRIPTION OF T HE DRAWINGS [0019] In the figures which illustrate exemplary embodiments of this invention: [00201 Fig. 1 is a schematic diagram illustrating a evacuated-tube solar cooking appliances in vertical section and cross section view in accordance with a first embodiment; 3 [0021] Fig. 2 is a set of solar cooking appliances is illustrated schematically in a perspective view; [0022] Fig. 3 illustrates schematically a set of exemplary solar heat collectors in vertical section view; 10022a] Fig 4 is a schematic diagram illustrating an exemplary solar coffee/tea maker in vertical section in accordance with the second embodiment; and [0022b] Fig 5 is a schematic illustrating a solar/electric coffee maker in vertical section in accordance with the third embodiment DETAILED DESCRIPTION [0023] In the first embodiment, referring to Fig. 1, an evacuated-tube solar cooking appliance is illustrated in vertical section and cross section view during use. [0024] The solar cooking appliance 100 includes a solar heat collector 110, the first heat storage and conducting material 120, a second heat conducting/transferring medium 121, a solar cooking utensil 130, a removable part 114 of I10 and a removable part 131 for 130, and a electric heat element 150 with power supply. [0025] Solar heat collector may be any kind of solar heat collector that can heat the first heat storage and conducting material 120 to the temperature higher than the water boiling temperature, In this case, the solar heat collector 110 is an evacuated-tube solar heat collector. It may also is a group of modular evacuated-tube solar heat collectors that mounted in a certain shape, e.g. in parallel row, in full or partial cone-shaped column as its one of the examples shown in Fig 2. The solar heat collector 110 has a removable part 114 with two holes 1141 and 1142. The hole 1141 is a path of power cable and air. The holel 142 is to continue the hole 1311 for releasing of cooking steam. 100261 The evacuated-tube solar heat collectors 110 has transparent outer layer 111 and inner layer 112. It is evacuated in between. The inner layer 112 has a heat absorbing coating that does not show in the Fig 1. The evacuated-tube solar heat collector 110 has the same material and manufacture processing as the evacuated-tube solar heat collector that used for solar water heating. But the evacuated-tube solar heat collector used in solar cooking has a larger diameter and comparing to the regular evacuated-tube. 100271 The evacuated-tube solar heat collector 110 is made of glass. In case the glass tube is broken, the glass piece is dangers for the user. So the solar heat collector has a transparent (e.g. plastic) cover for safety reason. (not shown in Fig. 1). The transparent plastic cover can be either the mantles for each tube or a protective cover for an entire collector panel. But the plastic protective mantles may reduce the efficiency of the solar heat collector. So an evacuated toughened-glass tube solar heat collector is a better solution. 4 100281 The first heat storage and conducting material 120 in this case is salt or quartz sand for storing the solar heat and transferring heat to the cooking utensil 130. In fact, many kinds of the materials can be used as the solar heat storage and conducting material. For example, they are solid materials such as salt and sand, liquid material such as water and oil, including cooking oil and petroleum products, phase change material, such as paraffin and metals. The cook takes place in the tube wherein utensil is located, so the food safety needs to put special attention. In this invention, we prefer the salt, quartz or basalt sand, and large piece of metal. For the first heat storage and conducting materials, further to the materials mentioned above, metal or alloy conductors and heat tube are suggested. [00291 In Fig.1 there is second heat conducting/transffering material 121. In this case, this is a copper conductor in T shape inserted in the heat storage and conducting material 120 for faster transferring the solar heat to the cooking utensil 130. The conductor 121 can be any other heat conductivity conductor or a heat tube. The second heat conducting/transferring material 121 is not a necessary component. In many cases, without the heat conducting material 121, the solar cooking appliances work well. [0030] The cooking utensil 130 is a cylinder container located inside of solar heat collector 110 upper the salt or sand 120. It made of stainless steel. The cooking utensil 130 has a removable part 131 with a hole 1311, it is a stopper inserted in the cooking utensil 130. The utensil has a diameter near but not bigger than the inner diameter of the evacuated-tube solar heat collector 110. A pleated structure 133 is on the wall of the container from the top to the bottom to provide a gap and patch for air exchange and power cable 151. Furthermore it allows a minor adjustable diameter for the container 130. The cooking utensil 130 further includes a removable and detachable handle 135 at the inner wall for removing the utensil 130 from the solar heat collector 110. [00311 In Fig.1, the utensil 130 is a food steamer. Three layers of steam basket are arranged in the utensil upper the water in the bottom. The food is cooked on the steam basket. In fact, the cylinder container, i.e. the utensil 130, can be many kinds of the utensils. We can have a set of cylinder containers for different cooking purposes. For example, second container can have water and coffee or tea for cooking. It is a solar coffee/tea maker. Third container can have a wire mesh container to hold food when frying and drain them after cooked. It is a solar cooking fryer. Fourth container can have a whisker net made of several curved and intersecting steel wires used to press the food sheets close to the inner wall of container for roasting or baking. Fifth container can back and roast breads and cookies. Of cause, if in the container food and water are arranged for braising or boiling. It is a cooking wok or pot. Based on above descriptions, it is believed that other modifications to the utensils used in this solar heat collector 110 will be apparent to those skilled in the art and, therefore, the invention is defined in the claims. [0032] A removable part 114 covers the top of solar heat collector 110. It has two holes 1141 and 1142. The first hole 1141 connects to said gap and path for air exchange and power cable 133. The second hole 1142 continues the hole 1311 in the stopper 131 of the container 130. The stopper may be a plant fibril cork with an air gap or a hole. 5 {0033] The electric heat element 150 with power supply is a very low power electric heat element. It located under the cooking utensil 130 and/or within heat storage and conducting material 120. A power cable 151 has very high resistive heat temperature that connects the electric heat element 150 to power supply plug 152 outside of the solar heat collector 110, through the path formed by a pleated structurel33 on the walls of the utensil 130. The electric heat element 150 may further includes a measuring, indicating and controlling systems for the solar cooking appliance's operating characteristic parameter, e.g. timing, temperature, pressure, moisture etc. These equipments are not shown in Fig. 1. The electric heat element with power supply can be in solar cooking utensil or removed from the set of cooking appliance. In this case the set of solar cooking appliances is still a complete cooking appliances that use solar heat as only energy source. Fig. 3 shows the solar heat collectors without electric heat element. [0034] Some time the evacuated-tubes are mounted in a row for cooking several foods at the same time. [00351 Refer to Fig. 2, a set of solar cooking appliances 200 is illustrated schematically in a perspective view. Five evacuated tube solar heat collector 201, 202, 203, 204 and 205 are mounted in a parallel row. 100361 A fixing and supporting trestle 206 arranges and supports the five solar heat collectors at the proper locations and situations. The movable support 207 allows the adjustment of the incidence angle of the solar heat collector 210 to the sunlight. Four wheels 241, 242, 243 and 244 are installed in the four bottom corners of the supporting trestle 206 for adjust the direction of the solar heat collector 210. (243 and 244 are not shown in Fig.2). A sundial (not shown in Fig. 2) is a cone bar. It attaches to the solar heat collector 210 perpendicularly for indicating the incidence angle of sunlight; [00371 A light reflecting object (not shown in Fig. 2) is equipped under the evacuated tube for focusing the surrounding sun light to the solar heat collector; [0038] When the solar light shines on the solar heat collector 210, the cooking processing in each utensil is the same as the processing mentioned in Fig. 1, and will not be further described. t00391 In the second embodiment, referring to Fig.4, a schematic exemplary solar coffee/tea maker 400 is illustrated in vertical section view. The solar coffee/tea maker 400 includes a solar coffee/tea pot 460, a solar heat collector 410 and their connecting conduit 471. The solar heat collector 410 is filled with heat storage and conducting material 420. [0040] The solar coffee/tea pot 460 is a liquid container with a lid 462. In this case it is a vacuum glass bottle 461. But the stainless steel and synthetic material are also often be used. A coffee/tea holder 466 is disposed in the pot 460. The coffee/tea holder 466 has its lower part of tea basket 467 with removable lid 4671. The upper part of the coffee/tea 6 holder 466 is a punched coffee holder 468. A stand 469 supports the coffee holder 468 and tea holder 467. All three parts of coffee holder, tea holder and its lid can be moved through the axis 469. Based on the cooking requirement, either coffee holder or tea holder or both of them can be stayed in or removed out from the pot 460. 10041] A hot water shower head 464 is arranged at the center of lid 462. A hot water conduit 463 passes through and is hidden in the lid 464 and the handle 465 of the pot 460. The hot water conduit 463 connects the water shower head 464 at one end. The opposite end of the hot water conduit 463 is connected to a fitting 470 that is at a lower part of the handle 465. The fitting 470 is for receiving a hot water conduit 471 from a solar water heater 410; [0042J Solar heat collector 410 may be any kind of solar heat collector that can heat the heat storage and conducting material 420 to the temperature more than the water boiling temperature. In this case the solar heat collector 410 is an evacuated-tube solar heat collector. It may also is a group of modular evacuated-tube solar heat collectors mounted in a certain shape, e.g. in parallel row or in full or partial cone-shaped column as of the examples shown in Fig 2. The solar heat collector 410 has a removable part 414 with two holes 4141 and 4142. The hole 4141 is a path for power cable 451 and air exchange. The hole 4142 is to continue the hole 4311 for a hot water conduit 471 to go through. [0043] The evacuated-tube solar heat collectors 410 has transparent outer layer 411 and inner layer 412. It is evacuated in between. The inner layer 412 has a heat absorbing coating that does not show in the Fig 4. The evacuated-tube solar heat collector 410 has the same material and manufacture processing as the evacuated-tube solar heat collector that used for solar water heating. But the evacuated-tube solar heat collector 410 used in solar cooking has a larger diameter and a shorter length comparing to the regular evacuated-tube for solar hot water. [0044] The evacuated-tube solar heat collector 410 is made of glass. In case the glass tube is broken, the glass piece is dangers for the user. So the solar heat collector 410 has a transparent plastic cover for safety reason. (It is not shown in Fig. 4). If the solar heat collector 410 is a group of evacuated-tubes mounted in row, the transparent plastic cover may cover each tube or a plastic protective mantle may cover entire raw. But the plastic protective mantle may reduce the efficiency of the solar heat collector 410. So an evacuated toughened-glass tube solar heat collector is a better solution. [00451 The evacuated-tube solar heat collector 410 is filled with a heat storage and conduction material 420. The heat storage and conducting material 420 in this case is salt or stone sand for storing and transferring the solar heat to the water container 430. In fact, many kinds of the materials can be used as the solar heat storage and conducting material. For example, they are solid materials such as salt, sand, graphite and turves. They can be liquid material, such as water and oil including cooking oil and petroleum products. They also can be phase change material, such as paraffin. The combination of different materials, such as bean oil in quartz sand, is also a choice. 7 [0046] The water container 430 is a cylinder container located inside of solar heat collector 410 upper the heat storage and conducting material 420. It made of stainless steel. The cooking utensil 430 has a removable part 431 with a hole 4311, it is a stopper inserted in the cooking utensil 430. The utensil has a diameter near but not bigger than the inner diameter of the evacuated-tube 410. A pleated structure 433 is on the wall of the container from the top to the bottom to provide a gap and patch for air exchange and power cable 451. Furthennore, it allows a minor adjustable diameter for the container 430. The cooking utensil 430 further includes a removable and detachable handle 434 at the inner wall for remove the utensil 430 from the solar heat collector 410. [0047] A removable part 414 covers the top of solar heat collector 410. It has two holes 4141 and 4142. The first hole 4141 connects to said gap and path for air exchange and power cable. The second hole 4142 continues the hole 4311 in the stopper 431 of the container 430. [048] The electric heat element 450 with power supply is a very low power electric heat element. It located under the water container 430 and within heat storage and conducting material 420. A power cable 451 has very high resistive heat temperature that connects the electric heat element to power supply plug 452 outside of the solar heat collector 410, through the path formed by a pleated structure 433 on the walls of the utensil 430. The electric heat element 450 may further includes a measuring, indicating and controlling systems for the solar cooking appliances operating characteristic parameter, e.g. timing, temperature, pressure, moisture etc. These are not shown in Fig 4. The electric heat element with power supply can be removed from the set of cooking appliance. In this case the set of solar cooking appliances is still a complete cooking appliances that use solar heat as only energy source. 100491 A hot water connecting conduit 471 is extended into said airtight solar heated water container through the holes 4142 and 4311. Its one end is submerged under the water level 435 in heated water container 430. The opposite end of said hot water connecting conduit 471 is connected with a conduit connecting fitting 470 at said handle 465 of coffee/tea pot 460. [0050] When the solar light 401 shines on the solar heat collector 410, the solar heat collector absorbs the solar heat and stores it in the sand 420. When the water container 430 is put into the solar heat collector 410 and the cool water is poured in, the solar heat is transferred to the solar water container 430 through the inner wall 412, heated sand 420 and heats the water. The conduit 471's end 4711 is submerged under the water level 435 in water container 430. The water container 430 is airtight. When the water is heated to boiling, the water steam gathered in the upper space of the container 430 forces the hot water flows up the conduit 471 and 463. Then the hot water is dispersed to drip evenly on the coffee grounds waiting on the coffee holder 468 through the shower head 464. The hot water picks up the coffee essence and down into the coffee bottle 461. A coffee making processing is completed. A similar processing can be used for making tea. In this case the tea or tea bag can be put in the tea basket 467. 8 [0051J We can also replace the water container by using the evacuated-tube 110 itself In this case, there are no water container 430, its stopper 431 and heat storage and conducting material 420 inside of the solar heat collector 410. The removable part 414 needs to make the collector 410 becomes an airtight container. When the solar heats the water in the evacuated tube 410 to boiling, the water steam in the evacuated tube 410 presses the water upward and through the conduit 471 and 463 to make coffee. In this case the speed and quantity of coffee making are dependent on the real time solar power. It may be not continued and stable. When we use the water container 430 located in a evacuated tube 460 filled with heat storage and contacting material 420, we can use the stored heat to make coffee and tea at any time continuously and stably. [0052] When the solar heat is not enough for cooking, electric element 450 heats the water container inside of the solar heat collector 410. Because the tube 410 has very good heat insulation feature, so the required electric power is very low. In this case, the electricity has very high cooking efficiency. [00531 Based on the idea of a solar coffee/tea maker mentioned above and in Fig. 4, a solar/electric coffee maker can be easily manufactured by making a minor change to an electric heated drip coffee maker or by reequipping a existing electric heated drip coffee maker. In the third embodiment referring to Fig. 5, a schematic solar/electric coffee maker 500 is illustrated in vertical section view. To make the description simpler, the solar heat collector 510 including the filled heat storage and conducting material 520, the solar water boiler 530 and the connection conduit 571 are the same as mentioned in Fig. 4. [00541 An electric coffee maker 560 has its cool water reservoir 561, electric heated tube 562, hot water tube 563, hot water shower head 564, punched coffee holder 565, coffee pot 566 and first one-way valve 567. These parts mentioned above are as the regular parts that any electric drip coffee maker may have. Comparing to the regular electric drip coffee maker, the major changes of a solar/electric coffee maker are as follows: [0055] A hot water tube 563 continues the electric heated tube 562 and leads the water up from the base of reservoir 561 to the drip area 565. This hot water tube 563 has a bypass tube 568 located upper the first one-way valve 567 and electric heated tube 562, but lower the shower head 564; 100561 A second one-way valve 570 for preventing hot water flowing backward to solar heat collector 510 is added. Its one end connects to the end of said bypass tube 568 and its opposite end connects to a connecting fitting 569 at said electric drip coffee maker 560 through third tube 572. The connecting fitting 569 is for receiving a hot water tube 571 from a solar water container 530. 9 [0057] A third one-way valve 573 is equipped at the hot water tube 563 between the bypass 568 and electric heated tube 562 for preventing hot water from solar heat collector flows toward electric heated tube 562; [0058] A hot water connecting conduit 571 is extended into said airtight solar heated water container 530 through the holes 5142 and 5311. Its one end is submerged under the water level 535 in heated water container 530. The opposite end of said hot water connecting conduit 571 is connected with said conduit connecting fitting 569 at electric drip coffee maker 560, 100591 When the solar light 501 shines on the solar heat collector 510, the solar heat collector absorbs the solar heat and stores it in the heat storage and conduction material 520. When the water container 530 is put into the solar heat collector 510 and the cool water is poured in, the solar heat is transferred to the solar water container 530 through the inner wall 512, heat storage and conducting material 520 and heats the water. The conduit's 571 end 5711 is submerged under the water in the water container 530. The water container 530 is airtight. When the water is heated to boiling, the water steam gathered in the upper space of the container forces the hot water flows up the conduit 571 and 563. Then the hot water is dispersed to drip evenly on the coffee grounds waiting on the coffee holder 565 through the shower head 564. The hot water picks up the coffee essence and down into the coffee port 566. A coffee making processing is completed. When solar heat collector 510 works, the added one-way valve 573 prevents the water flows toward electric heated tube 562. [00601 When the solar energy is not enough, plug the electric heated tube 562. The cool water from 561 flows through the first one way valve 567 and is heated in electric heated tube 562 until boiling. The bubble in boiled water forces the hot water up to the shower head 564 through hot water tube 563 to make coffee. The processing is the same as the processing in any kind of electric drip coffee maker. 10061] When solar heat collector 510 works, the one-way valve 573 prevents the water flows toward electric heated tube 562. When electric drip coffee maker 560 works, the added one-way valve 572 prevents the water flows toward solar heat collector 510. If necessary, two heating sources also can work together. [00621 As mentioned in Fig. 4, an empty solar heat collector tube 510 can replace the hot water container 530 to heat the water and make coffee. [00631 Referring to Fig. 3, a set of exemplary solar heat collectors are illustrated schematically in vertical sections, which can be used in any of the embodiments. [0064] Fig. 3 A is a schematic vertical section view of an evacuated-tube solar heat collector partially filled with liquid heat storage and conduction material, e.g. water or oil. In some cases, water can also be a heat transferring medium for food cooking. 10 [0065] Fig. 3 B is a schematic vertical section view of an evacuated-tube solar heat collector partially filled with first solid heat storage and conduction material, e.g. ore stone or turves. [00661 Fig. 3 C is a schematic vertical section view of an evacuated-tube solar heat collector partially filled with sand and having a heat tube or a heat conductor as the second heat conducting/transferring material . [00671 Fig. 3 D is a schematic vertical section view of an evacuated-tube solar heat collector partially filled with a combination of solid and liquid heat storage and conducting materials, e.g. quartz sand and cooking oil; [0068] Fig. 3 E is a schematic partial vertical section view of a group of modular evacuated-tube solar heat collectors that mounted in a vertical parallel raw; [0069] Fig. 3 F is a schematic partial vertical section view of a group of modular evacuated-tube solar heat collectors that mounted in a horizontal parallel raw; [0070] When set up a solar cooking appliance, not only these kinds of solar heat collectors but also more kinds of their varieties and combinations can be selected and used. [0071] Based on the detailed description of the samples, other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims. 11

Claims

1. A solar cooking appliance, comprising: a tubular solar heat collector to collect and store solar heat, having: a heat storage and conducting material partially filling said tubular solar heat collector, wherein said tubular solar heat collector can heat said solid heat storage and conducting material; a solar cooking utensil removably locatable within the tubular solar heat collector, wherein said solar cooking utensil is sized to fit a size and shape of the internal size and shape of the solar heat collector, and said utensil having a wall which is thermally connected to the internal wall of the solar heat collector and the heat storage and conducting material to transfer heat to the utensil, and said utensil having a removable part for opening and closing said utensil; and a removable part to cover the top of the tubular solar collector.

2. A solar cooking appliance as claimed in claim 1, including: an electric heater providing a back up of heating source and electric heat storage, comprising: an electric heating element located under the solar cooking utensil and within said solid heat storage and conducting material.

3. A solar cooking appliance as claimed in claim 1 or 2, wherein said tubular solar heat collector is an evacuated-tube solar heat collector.

4. A solar cooking appliance as claimed in any one of the preceding claims, wherein said heat storage and conducting material is selected from a group of: salt, sand, quartz sand, a solid chemical material, a solid multi- H20 chemical material, a basalt 12 sand, a metal conductor, copper conductor, heat conductive alloy, ore stone, turves, liquid material such as water or oil, cooking oil or petroleum products, phase change material such as paraffin or metals, and a combination of two or more above mentioned heat storage and conducting materials.

5. A solar cooking appliances as claimed in any one of the preceding claims, wherein said heat storage and conducting material is selected from a group of: a combination of two or more different solid materials mixed with some liquid material, wherein said liquid material can be heated to a temperature higher than the water boiling temperature, the group including quartz sand containing colza oil, and basalt sand containing bean oil.

6. A solar cooking appliance as claimed in any one of the preceding claims, wherein said solar cooking utensil is selected from a group of: a stainless steel container having a removable and detachable handle at an internal wall and a pleated structure on a external wall to provide a gap and path for air exchange and allow a minor adjustable diameter for said container; a coffee maker; a tea maker; a steamer; a fryer with a wire mesh for frying and draining a food; a whisker net to press the food to an internal wall of said utensil for food roasting and baking; a wok; a pot, and a pan.

7. A solar cooking appliance as claimed in any one of the preceding claims, including a further heat conducting/transferring material located within said solar heat collector and thermally connected to said solid heat storage and conducting material for faster 13 transferring the solar heat to said cooking utensil, wherein said further heat conducting/transferring material is selected from a group of: a heat tube, a metal conductor, an alloy conductor and a heat conductive conductor.

8. A cooking appliance as claimed in any one of the preceding claims, wherein a plurality of tubular solar heat collectors in the form of evacuated tubes are arranged in a module and are supported by a trestle having an inclining structure for adjusting angle of said solar heat collector to sunlight, a directional structure for adjusting direction of said solar heat collector to sunlight, a light reflector to focus surrounding sunlight to the solar heat collector, and a sundial attached to the solar heat collector perpendicularly for showing the angle of the sun light.

9. A solar cooking appliance as claimed in any one of the preceding claims as dependent on claim 2, wherein said removable part of the utensil and said removable part of the solar collector are both formed with holes; and wherein said electric heater comprises a power cable having very high heat resistant temperature connected to an electric heating element via a power supply plug outside of the solar heat collector through a path formed by a pleated structure on the walls of the containers and the holes in the removable parts of the utensil and solar collector.

10. A solar cooking appliance as claimed in any of the preceding claims, wherein the solar cooking utensil includes a separate container remote from the solar collector and a connecting conduit extending at one end into the solar utensil and at the other end to the separate container to allow hot water to flow from solar utensil on heating to the separate container.

11. A solar cooking appliance as claimed in claim 10, wherein the removable part of the solar collector makes the solar collector airtight. 14

12. A solar cooking appliance as claimed in claim 10 or 11, wherein the separate container is a coffee or tea maker. 15