NZ203081A

NZ203081A - Heating or cooking unit with solar collector;upwards sloping heat pipe;heat storage block;and a heating and cooking element

Info

Publication number: NZ203081A
Application number: NZ203081A
Authority: NZ
Inventors: Bernd Stoy; Erich Poehlmann
Original assignee: Bernd Stoy; Erich Poehlmann
Priority date: 1982-07-17
Filing date: 1983-01-25
Publication date: 1986-06-11
Also published as: DE3275119D1; ES8308038A1; AU1070283A; CA1240892A; EP0099423A3; JPS5914830A; IN155654B; BR8300353A; GR77377B; EP0099423B1; EP0099423A2; DE3226782A1; ATE24962T1; AU567866B2; ES517529A0; DE3226782C2

Abstract

1. A heating and/or cooking appliance (1) with a solar collector (2) for the absorption of heat and a storage block (3) for its storage, at least one heat tube (4) connecting the solar collector (2) to the storage block (3) and to a heating and/or cooking unit (5) in which the heat tube (4) is led upwards from the solar collector (2) to the storage block (3), at least during the absorption of heat, characterized in that either the heating and/or cooking unit (5) is connected to the storage block (3) by the heat tube (4) that also connects the solar collector (2) to the storage block (3) and for heating and/or cooking the heat tube (4) is led upwards from the storage block (3) to the heating and/or cooking unit (5), or the heating and/or cooking unit (5) is connected to the storage block (3) via a further heat tube (10) and that for heating and/or cooking the further heat tube (10) is led upwards from the storage block (3) to the heating and/or cooking unit (5).

Description

<div class="application article clearfix" id="description"> 203081 Priority Date(s): I J..7.. Complete Specification Filed: . I. Class: Y.V.L/0.3. /.Q1? Publication Date: .. .(■'! .1 M6 P.O. Jotsrnal, No: ... ........... i Patents Form No. 5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION ""HEATING OR COOKING-DEVICE WITH A SOLAR COLLECTOR" WE, DR.-ING. BERND STOY, of Am Scharfenstein 6, 4030 Ratingen 8, West Germany and ERICH POHLMANN, of Kadalohbeinsweg 1, 8650 Kulmbach, West Germany, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement - 1 - (followed by page 1A) 203081 The invention relates to a heating or cooking-device with a solar collector for the absorption of heat, a storage block for storing heat, at least one heat-pipe connecting the solar collector to the storage block and a heating and cooking-element, in which case the heat-tube at least during the absorption of heat slopes upwards from the solar collector to the storage block. In the present state of the art from which the invention starts out, there is a known heating device of the previously described type in which a heat.pump is coupled to the storage block and the heating element is coupled in turn to the heat pump. The problem to be solved by the invention is to configure the known heating device and to develop it further in such a way that it can operate without the need for using the heat pump and indeed not only as a heating device but also and in particular as a cooking device. According to the present invention a heating or cooking device comprises a solar collector for heat absorption, a storage block for heat storage, a heat pipe connecting the solar collector with the storage block and a heating and cooking element in heat communication with the storage block, the heat pipe connecting the solar collector to the storage block being arranged to slope upwards towards the storage block during a heat-absorption ' and -storage mode, characterized in that the solar collector, storage block, heating and cooking element, and heat pipe are -rranged in a fixed relative relationship and the device can °^Jbe manually converted to a heating or cooking mode. la 203081 In one arrangement the solar collector and the heating and cooking element are constructed as a sub-unit which is connected with the storage block by the heat pipe and the device can be converted to the heating or cooking mode by being turned upside down as a unit so that the heat pipe from the storage block to the sub-unit slopes upwards to the heating and cooking element of the sub-unit. In another arrangement the heating and cooking element and the storage block are constructed as a sub-unit. In a further arrangement the heating and cooking element is connected to the storage block by an additional heat pipe and the device can be converted to the heating or cooking mode wherein the additional heat pipe slopes upwards towards the heating and cooking element for thepurpose of heating or cooking. The heating or cooking-device is intended particulary for torrid zones of the earth, for desert regions or the like and is adaptable to these regions. In contrast to the heating or cooking-devices which have been known now for a long time and which have foldable parabolic mirrors, there is no necessity with this present heating or cooking-device to carry on heating or cooking 2 2030*1 immediately during the time of solar irradiation. Much rather than this there is storage block provided for storing the energy coming from the sun which has been transformed into heat, so that heating / cooking can always be carried on during the cooler hours of the evening. In the case of the heat pipe which has been referred to earlier it is a matter of a tube made from suitable material which is closed at both ends which is partly filled to a small extent with a liquid cooling medium. This cooling medium does not have an all too high boiling point. If the heat pipe is arranged with a definite least slope, the ascent angle, then heat can be transported from its lower end to the end which is situated at a higher level. This happens because the cooling medium at the lower warm end of the tube begins to vaporize and the evolved vapor ascends to the upper cooler end of the tube where it condenses and releases its heat. The condensate flows back to the lower end of the tube so that a heat transfer circulation is established. Transfer of heat from the upper end to the lower end of the tube is naturally not possible. Furthermore, it has been demonstrated that an ascent angle of at least 6° to 7° is necessary to ensure the adequate flowback of the condensate. In the form of embodiment where the heating and' cooking-element in accordance with the invention is connected to the storage block by means of the heat pipe which also connects the solar collector to the storage block, it is a simple matter to reverse the direction of heat transport just bv tilting the heat pipe.> For ntbde ' mode changing of the heat-absorption and -storage/toheating or cooking/the unit can simply be used as consisting of solar collector, storage block, heat pipe and heating' amd "; cooking-element, so that the heat pipe for heating or cooking is arranged to pass upwards from the storage block to the heating-and cooking-element. The heat which has been stored during tine day can then be transported through the heat pipe to the heating- and cooking-slemenc to be used there for heating or cooking. 203081 The heating - or cooking-device in accordance with the invention, in which the heating- and .cooking-element is connected to the storage block by means of the heat pipe which connects the solar collector to the storage block , represents very considerable improvement over the known heating or cooking-devices with foidable parabolic mirrors because now the cooking or heating can be done at any desired time during the day. It is possible to store up to A to 5 kWH of energy in the form of heat without having a storage block of excessive dimensions. If it be borne in mind that a family of four people requires about 1 kWH of energy for the preparation of a meal then it is an easy matter to provide the heat for the heating or cooking-device in accordance with the invention for the large families which are the general rule in the torrid zones of the earth. & With the heating or. cooking-device in accordance with the invention, in which the heating and cooking-element is connected to the storage block by means of the heat pipe which connects the solar collector to the storage block , in which case the solar collector and the heating- and - cooking-element are constructed as a unit, the heat from the storage block can be transferred to the heating and cooking-element during heating or cooking as desired on the one hand, and if it is not desired to do this then, on the other hand the heat can be transferred to the solar collector. Thus heat would be lost through the solar collector during heating or cooking. An improved form of embodiment taking this disadvantage into account is characterized by the fact that a heat insulation element is provided so that during heating atMfrfor cooking the solar collector can be covered over by this heat insulation element and preferably the heating and cooking-element can be covered over by this heat insulation element during the period of heat absorption and storage. Here it is recognized that transfer of heat from the storage block to the solar collector during heating or cooking cannot be prevented but that it is possible to a very large extent to prevent the loss of heat from the solar collector to the surroundings at this time by the use of the heat insulation element which is provided additionally. Under these circumstances use is made of the fact that the heating or cooking-device under discussion for cooking or heating needs to have the heating and , cooking-element along with the associated solar collector raised up with respect to the storage block in order to obtain the requisite ascent angle for the heat pipe. It it be started out from the premise that the storage block must remain on the ground all the time because of its weight, then the solar collector and the heating- and cooking-element, turned through 180° with respect to heat absorption and storage, must be raised up above the ground level. In this way the heat insulation element can be pushed under the solar collector without any trouble. If the construction is appropriately and skilfully carried out then the heat insulation element can be used in both functional situations - heat-absorption and -storage on the one hand, and heating or cooking on the other hand - so that during heat-absorption and -storage the heating- and>*e^ cooking-element is covered over by the heat insulation. In the form of embodiment of the heating- or \ cooking-device in accordance with the invention in which the heating--, and cooking-element is connected directly to the storage block , the storage block can be provided with a removable cover and insulation plate for heating and^or cooking, preferably on its upper side. It is recognized here, in accordance with the invention , that it would be possible to dispense with a heating and cooking-element which is separated from the storage block if the heating and cooking-element is implemented as a functional-integral component of the storage block. With this form of heating-■ei'id^'or cooking-device the heat is therefore derived directly from the storage block, because the storage block is exposed simply by taking off the cover- and insulation-plate which is preferably located on Its upper side. The type of construction which has just been described has the special advantage that the heating or cooking-device is really optimal from the manipulative-technical point of view, because there is no need for a turning around of the unit consisting of the solar collector, storage block , heat pipe and heating, and cooking-element . This type of construction is also optimal from the point of view of minimizing heat loss because the heat is withdrawn directly from the storage block. - 5 - 2030S1 In the pre;vioiusly described heating or cooking device, in which the heating-and ' , cooking-element is thus preferably located beneath the removable cover-and insulation-plate, after removal of the cover- and insulation-plate a saucepan or frying pan or the like can be placed on the heating and., cooking-element which represents the upper limiting surface of the storage core. This is however still not optimal because the temperature of the interior of the storage block, that is to say the temperature of the storage core is not particularly high. Even when it is taken into consideration that the storage core itself during the course of the day can become heated up to the so-called idling-temperature of the solar collector, this temperature does not exceed 500 K to any considerable extent. This is far below the temperature which is attained with cooking devices which are operated on gas or electricity. When using a saucepan, a frying pan .or the like, temperature differences occurring between the heating and cooking-element and the saucepan , frying pan or the like is disadvantageous. Consequently a further concept of the invention consists of configuring the heating- and cooking-element directly as a cooking-trough or the like, thus providing a saucepan, frying pan or the like as an integral component of the heating and cooking-elepent. If a plurality of cooking-troughs are present in the heating and cooking-element then it is possible to cook various kinds of cooking materials at the same time. In the previously described heating- and/or cooking-device certain problems can arise because of the cover- and insulation-plate of the storage block located on the storage block itself, so that it is not possible to achieve optimal heat insulation and so optimal heat storage also cannot be achieved. Besides this, it is not possible with this heating -or. cooking-device to alter the heating- and cooking-temperature in the way that this can be done with separate heating- and • cooking-element by inclining the heat pipe at different angles. In the form of embodiment of the heating or cooking-device in accordance with the invention, in which the heating and " cooking-element is connected to the storage block by a further heat pipe, a heating- and * cooking-element which is separate not only from the solar collector but also from the -xcT- -4 2.030S1 from the storage.block may be implemented which is connected to the storage block with a heat pipe of its own. The necessary alteration to the ascent angle of this heat pipe for changing over from heat-absorption and -storage to heating aod>*or cooking can be achieved by having the heat pipe attached to the storage block by means of a pivoting bearing connection. This is especially possible when a liquid or a salt with low melting-point is used as the storage medium in the storage block. Different ascent angles of the heat pipe can then lead to different heating- 'anchor cooking-temperatures at the heating- and»^«fr cocking-element. The previously mentioned pivoted bearing connection of the heat pipe of the heating- and cooking-element to the storage block is technically not without problems. A type of construction of the heating or cooking-device in accordance with the invention which recommends itself as a simple alternative is characterized in that the storage block is provided with a plurality of openings into one of which openings the heat pipe can be selectably inserted to achieve different ascent angles for the heat pipe connecting the heating and cooking-element to the storage block. Up till now the discussion has been confined to the situation where only one heating- and cooking-element is provided and where the heat pipe of this heating-and«*» cooking-element can be adjusted at different ascent angles for heating-and/or cooking as circumstances .demand. Naturally it is also possible to provide a plurality of heating and, cooking-elements, each one of which is connected .to the storage block by heat pipes of their own which are inclined at different ascent angles, or else to adopt procedures which lead to the appropriate locating of the heat pipes. In this way it is thus possible to attain different temperatures on the various separate heating and - cooking-elements. According to a further theoretical concept of the invention in the form as just discussed which is of particular importance, the ascent angle of the heat pipe -7- connecting the heating and , cooking-element with the storage block is less than the ascent angle of the heat pipe connecting the solar collector with the storage block and for changing over from heat-absorption and -storage to heating or" cooking the unit consisting of solar collector, storage block, heating-and • cooking-element and heat pipe may be tilted by raising of the solar collector in relation to the storage block by at most the ascent angle of the heat pipe connecting the solar collector with the storage block. This construction is particularly simple because the solar collector, the storage block, the heating-■and cooking-element and the heat pipes can be arranged in a fixed spatial configuration with respect to one another. By lifting up the solar collector the heating- and^®s»cooking-element is also lifted up at the same time; Because the ascent angle of the heat pipe connecting the heating- -and ■ cooking-element with the storage block during heat-absorption and -storage is less than the ascent angle of the heat pipe connecting the solar collector with the storage block, it so happens that the heat pipe between storage block and)heating and cooking-element will be ascending towards the heating- and ./ cooking-element at the latest when the heat pipe between solar collector and storage block has arrived at a horizontal position. By lifting up the solar collector in relation to the storage block in the manner of handling a "wheelbarrow", a "switching-over" from heat-absorption and -storage to heating and/or cooking is achieved. The previously described form of embodiment of a heating- «w^or cooking-device is extremely simple to manipulate technically, and it likewise presents all,the technical-servicing advantages of a separately arranged heating- and cooking-elemer The construction can also be utilized in a corresponding fashion even with a heating- or cooking-device without separate heating- and cooking-element so that heat is obtained directly from the storage block, which means that the transfer of heat from the solar collector to the storage block can be interrupted. In a further configuration of the form of embodiment which has just been discussed for a heating- or- cooking-device it is recommended that the solar collector 203081 be provided with a support foot of appropriate length which may be swung into position. Instead of such a swing-out foot a telescopic type of foot or the like can also be used. By varying the length of the support foot it is quite easy to alter the ascent angle of the heat pipe. Preferably the storage block also has a support foot, in which case this foot, and in certain circumstances, also the foot on the solar collector are provided with roller casters. Thus it is possible to transport the whole heating- nanaMor cooking-device from place to place without . much effort. It will have become clear from the foregoing discussion that the heat transfer between the storage block and the heating- and' cooking-element or else from solar collector to storage block can be influenced by the ascent angle between the storage block and the heating- and .cooking-element. Making use of this fact I there is a further theoretical concept of the invention that the ascent angle between the solar collector and the storage block and/or the ascent angle between the storage block and the heating and cocking-eiement can be regulated in dependence upon the temperature, so that the heat transfer between storage block and the heating- and cooking-element and/or the heat transfer between the solar collector and the storage block can be regulated and/or the storage temperature and the heating or cooking temperature can be controlled or regulated. This control can be effected by the use of bimetal-elements. So far nothing has been said as to how the solar collector of the heating- or cooking-device in accordance with the invention can be most expediently configured. There are already actual solar collectors of the type being discussed which are known in the most diverse forms of embodiment. Particularly simple from a constructional point of view is a heat-tube - flat-collector with a large area of blackened absorption surface. With such a heat-tube - flat-collector it is possible 2 to attain heat-efficiencies of ca. 200 W/m . The idling-temperature of such types 203081 of solar collectors is somewhere about 470 to 500 K. In order to achieve the greatest possible specific efficiency and to increase the idling-temperature, it is recommended that the solar collector should be configured as a vacuum - flat-collector. Such a vacuum - flat-collector consists of a plurality of parallel, evacuated glass tubes which are provided with selective absorption layers on the bottom half of their internal surfaces. The solar energy is for the most part converted to heat in the absorption layers which is transferred through the thin walls of the glass tubes to the heat tubes which run along underneath the glass tubes. With this type of vacuum - flat-collectors, which are technically relatively expensive, it is possible 2 to attain specific heat efficiencies of up to 400 W/m and idling-temperatures of up to 530 K and more. The media to be considered as heat-storage medium for the storage block include appropriate liquids, salts with appropriate melting-points, etc., as well as various solid materials which are known for use as he3t-storage media. I Even though there has been reference in the foregoing description to the alternatives of heat-absorption and -storage on the one hand and cooking on the other hand, this naturally does not signify that both of these processes cannot take place concurrently with the appropriate construction of the heating- .DnnVor cooking-device. This represents a very real possibility according to the concept of the invention which has just been expounded. For example, the heating- and cooking-element can be provided with attachable ribs or the like so that, particularly on cooler nights, the heating or cooking-device can be used as a heat radiator subsequent to its use in cooking operations . In the material which follows the invention will once again be explained in detail for a single example of embodiment with reference to the drawings where there is depicted in : Fig. 1 a diagrammatic section of a first example of embodiment of a heating-&ne¥or cooking-device in accordance with the invention, - IO - 2 03 OS 1 Fig. 2 a diagrammatic sectionof a second example of embodiment of a heating- 'gnd/or cooking-device in accordance with the invention, Fig. 3 a diagrammatic section of a third example of embodiment of a ■ heating- onriifor cooking-device in accordance with the invention and Fig. 4 a representation of the object of Fig. 3 in another position. The heating or • cooking-devices 1 depicted in Fig. 1 and Fig. 4 are in the cooking position, whereas the heating- .aniAfor cooking-devices depicted in Fig. 2 and Fig. 3 are in the heat-absorption and -storage positions. The heating or , cooking-device 1 depicted in Fig. 1 possesses a solar collector 2 for the absorption of heat, a storage block 3 for the storage of heat, a heat pipe 4 connecting the solar collector 2 with the storage block 3 and a heating and cooking-element 5. The solar collector 2, storage block 3 and the heat pipe 4 are surrounded as indicated by heat insulation material 7. It cannot be seen in Fig. 1 that the heat pipe 4 rises from the solar collector 2 towards the storage block 3 during the process of heat-absorption and -storage. What can be seen in Fig. 1 is that for cooking, namely in the depicted cooking position, the heat pipe 4 does ascend from the storage block 3 towards the heating- andj^ cooking-element 5. In order to prevent the undesirable loss of heat from the solar collector 2 to the surrounding atmosphere during the cooking process, a heat-insulation element 6 is provided for covering over the solar collector 2 during the cocking process. In Fig. 1 it can be seen that the heat-insulation element 6 has been pushed into place between the solar collector 2 and the surface of the ground. -J*- 203081 In addition to this, Fig. 1 shows that in order to improve the heat transfer to the heat storage medium which is not depicted in the diagram the heat pipe 4 is provided with heat-distribution ribs 8 inside the storage block 3. The heating- or cooking-device 1 as depicted in Fig. 2 also has a solar collector 2 for heat absorption, a storage block 3 for heat storage, a heat pipe A connecting the solar collector 2 with the storage blo^k^ and a heating and cooking-element During the heat-absorption and -storage/ the heat pipe 4 is inclined upwards from the solar collector 2 to the storage block 3. The characteristic feature here is that the storage block 3 has a removable cover- and insulating-plate 9 on its upper side and beneath the removable cover- and insulating-plate, 9 is located the heating-and . cooking-element 5 and this heating- and cooking-element 5 is constructed in the form of a cooking trough. In the case of the heating or - ,■ cooking-device 1 as depicted in Fig. 3 and Fig.4 along with the solar collector 2, the storage block 3, the corresponding heat pipe 4 and the heating and cooking-element 5 which have already been referred to repeatedly, there is also provision for an additional heat pipe 10; thus in this case the heating 'and cooking-element 5 is connected to the storage block 3 by way of the additional heat pipe 10. The heat pipe 10 connecting the heating and cooking-element 5 with the storage block 3 slopes upwards towards the storage block 3 during the heat-absorption and -storage process. The ascent angle of the heat pipe connecting the heating and cooking-element 5 with the storage block 3 in this case is less than the ascent angle of the heat pipe 4 connecting the solar collector 2 with the storage block 3. By comparing Fig. 3 with Fiq. 4 it can be seen that in order to change over from "mode mode heat-absorption and -storage/to heating owdji'or cooking.Ahe unit consisting of the solar collector 2, the storage block 3, the heating- and cooking-element 5 and the heat pipes 4, 10 may be tilted up by raising the solar collector 2 in relation to the storage block 3 making use of the heat pipe 4 connecting them. -,wr- - \2 - 203081 For the maintenance of the cooking position as depicted in Fig. 4 the solar collector 2 is provided with a fold-out support foot 11 of appropriate length. The storage block 3 is also provided with a support foot 12 which for its part is provided with a roller caster 13. In the introductory description it was stated that the heat pipe is partly filled with a liquid cooling medium. Instead of this cooling medium (in the restricted meaning of the term) it is also possible to use water if well-defined requirements are complied with. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 203061 WHAT WE CLAIM IS:

1. A heating or cooking device which comprises a solar collector for heat absorption, a storage block for heat storage, a heat pipe connecting the solar collector with the storage block and a heating and cooking element in heat communication with the storage block, the heat pipe connecting the solar collector to the storage block being arranged to slope upwards towards the storage block during a heat-absorption and -storage mode, characterized in that the solar collector, storage block, heating and cooking element, and heat pipe are arranged in a fixed relative relationship and the device can be manually converted to a heating or cooking mode.

2. A heating or cooking device as claimed in claim 1 in which the solar collector and the heating and cooking element are constructed as a sub-unit which is connected with the storage block by the heat pipe and the device can be converted to the heating or cooking mode by being turned upside down as a unit so that the heat pipe from the storage block to the sub-unit slopes upwards to the heating and cooking element of the sub-unit.

3. A heating or cooking device as claimed in claim 1 characterized in that the heating and cooking element and the storage block are constructed as a sub-unit.

4. A heating or cooking device as claimed in claim 1 characterized in that the heating and cooking element is 2.03081 ,^ the device can be converted to the heating or cooking mode wherein the additional heat pipe slopes upwards towards the heating and cooking element for the purpose of heating or cooking.

5. A heating or cooking device in accordance with claim 2, characterized in that a removable heat-insulation element is provided and during the heating or cooking mode the solar collector of the sub-unit can be covered over with the heat-insulation element and to convert it to the heat-absorption and -storage mode the heating and cooking element thereof can be covered over with the heat-insulation element.

6. A heating or cooking device in accordance with claim 3, characterized in that the sub-unit is provided when in the heat-absorption and -storage mode with a removable cover- and ptcxta, insulating-plate, on an upper surface,whichAcan be removed to convert it to the heating or cooking mode.

7. A heating or cooking device in accordance with claim 6, characterized in that the heating and cooking element is located beneath the removable cover- and insulating-plate and can be configured as a cooking trough. > » j

8. A heating or cooking device in accordance with claim 4, characterized in that the storage block is provided with a plurality of openings for the inserton of the additional heat pipe connecting the heatingand cooking element with the storage-, block to provide for different ascent angles of said additional heat pipe. // * o * if ^ - 15 - 14 MAR 1986-V. 203081

9. A heating or cooking device in accordance with claim 4, or 8/ characterized in that a plurality of heating and cooking elements are provided each one of them being connected to the storage block with at least one additional heat pipe and the additional heat pipes have different ascent angles or can be so adjusted.

10. A heating or cooking device in accordance with claim 4, characterized in that the additional heat pipe is arranged in fixed "Q'pojfea-al relationship to the storage block and the ascent angle of the additional heat pipe connecting the heating and cooking element with the storage block is less than the ascent angle of the heat pipe connecting the solar collector with the storage block and for changing over from the heat-absorption and -storage mode to the heating or cooking mode the device can be tipped up by raising the solar collector with respect to the far end of the storage block by an angle which is at most equal to the ascent angle of the heat pipe connecting the solar collector with the storage block.

11. A heating or cooking device in accordance with any one of the claims 1 to 10, characterized in that the solar collector is provided with a support foot which is of a fold-out type.

12. A heating or cooking device in accordance with any one of the claims 1 to 11, characterized in that the storage block is provided with a support foot which can be furnished with a roller caster. 203081

13. A heating or cooking device arranged, constructed and adapted to operate substantially as hereinbefore described with reference to any one of the embodiments shown in the accompanying drawings. ERND STOY and tcprneys & CAREY </div>