CA1240892A - Heating and/or cooking device using solar energy - Google Patents
Heating and/or cooking device using solar energyInfo
- Publication number
- CA1240892A CA1240892A CA000421860A CA421860A CA1240892A CA 1240892 A CA1240892 A CA 1240892A CA 000421860 A CA000421860 A CA 000421860A CA 421860 A CA421860 A CA 421860A CA 1240892 A CA1240892 A CA 1240892A
- Authority
- CA
- Canada
- Prior art keywords
- heat
- storage block
- solar collector
- heat storage
- heat pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S10/00—Solar heat collectors using working fluids
- F24S10/40—Solar heat collectors using working fluids in absorbing elements surrounded by transparent enclosures, e.g. evacuated solar collectors
- F24S10/45—Solar heat collectors using working fluids in absorbing elements surrounded by transparent enclosures, e.g. evacuated solar collectors the enclosure being cylindrical
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S20/00—Solar heat collectors specially adapted for particular uses or environments
- F24S20/30—Solar heat collectors for heating objects, e.g. solar cookers or solar furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S60/00—Arrangements for storing heat collected by solar heat collectors
- F24S60/30—Arrangements for storing heat collected by solar heat collectors storing heat in liquids
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
- Y02B40/18—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers using renewables, e.g. solar cooking stoves, furnaces or solar heating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/44—Heat exchange systems
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Combustion & Propulsion (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Cookers (AREA)
- Electric Stoves And Ranges (AREA)
- General Preparation And Processing Of Foods (AREA)
- Central Heating Systems (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
- Secondary Cells (AREA)
- Baking, Grill, Roasting (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A device to be used for space heating and/or cooking compris a solar collector connected via an inclined heat pipe to a heat store.
A thermal load, in the form of a heat-emitting plate, either is in direct contact with the solar collector or the heat store or is connected to that store via another heat pipe. The emission of heat can be controlled by changing the angle of inclination of the last--mentioned heat pipe or of the entire unit.
A device to be used for space heating and/or cooking compris a solar collector connected via an inclined heat pipe to a heat store.
A thermal load, in the form of a heat-emitting plate, either is in direct contact with the solar collector or the heat store or is connected to that store via another heat pipe. The emission of heat can be controlled by changing the angle of inclination of the last--mentioned heat pipe or of the entire unit.
Description
~LZ ~L~ 9 2 HEATING AND/OR COOKING DEVICE USING SOLAR ENERGY
SPECIFICATION
Field of the Invention Our present invention relates to a device for the utili-zation of solar energy, particularly for cooking and/or space heating.
Background of the Invention -Devices are known in which thermal energy, absorbed from the sun's rays by a solar collector, is stored in a heat reser-voir or tank connected through a heat pump to a thermal load such as a radiating element. Such a device has been described in lJ. S. patent No. 4,267,825 that also teaches the use of a pivoted heat pipe which in one angular position transmits heat from the collector to the reservoir and in another angular posi-~ 15 tion allows the withdrawal of heat from the reservoir to the col-''. ~
lector. Also known are devices in which incident sunlight is captured by a collapsible parabolic reflector for immediate uti-: .
~ ~ lization in a heater or cooker.
. .
The present disclusure provides a device for the purpose described which does not require a heat pump and, even when dimensioned to have a substantial heat-storing capacity, is of simple and relatively inexpensive construction.
Also disclosed are means in such a device For conveniently controlling the amount of stores thermal energy emitted in its operation as a heatlng or cooking stove.
~ 1 ~L~ 8~3~
A device here described comprises heat-transfer means linking its reservoir with a solar collector and its thermal load, the heat-transfer means including a partly liquid-filled conduit or heat pipe which has one of its ends disposed in heat-exchanging S relationship with the reservoir and its other end disposed in heat-exchangingrelationship with the load for transmitting thermal energ~ thereto in a heat-emitting position wherein that conduit is inclined to the horizontal at such an angle that the first-mentioned end lies at a level lower than that of the other end.
As is well known in the art, e.g. from the aforementioned U~ S. patent No. 4,267,825, the liquid partly filling the conduit referred to (which could be water but preferably is a fluid of lower melting point) is vaporized by a heat source at its lower end, the vapors rising to the upper end where they are condensed by an adjoining heat sink so that the heat carrier returns to the source in liquid form. The minimum angle of inclination of the conduit to the horizontal is usually about 6 or 7 degrees;
heat cannot be transmitted from the upper end to the lower one.
This property of one-way heat transfer is utilized, in accordance with a more particular feature of our invention, to minimize losses of stored thermal energy during idle periods in which heat is neither accumulated nor withdrawn. In a simple embodiment, in which one and the same conduit is used for -the transfer of thermal energy from the collector to the reservoir in a heat-absorbing position and from the reservoir to the load
SPECIFICATION
Field of the Invention Our present invention relates to a device for the utili-zation of solar energy, particularly for cooking and/or space heating.
Background of the Invention -Devices are known in which thermal energy, absorbed from the sun's rays by a solar collector, is stored in a heat reser-voir or tank connected through a heat pump to a thermal load such as a radiating element. Such a device has been described in lJ. S. patent No. 4,267,825 that also teaches the use of a pivoted heat pipe which in one angular position transmits heat from the collector to the reservoir and in another angular posi-~ 15 tion allows the withdrawal of heat from the reservoir to the col-''. ~
lector. Also known are devices in which incident sunlight is captured by a collapsible parabolic reflector for immediate uti-: .
~ ~ lization in a heater or cooker.
. .
The present disclusure provides a device for the purpose described which does not require a heat pump and, even when dimensioned to have a substantial heat-storing capacity, is of simple and relatively inexpensive construction.
Also disclosed are means in such a device For conveniently controlling the amount of stores thermal energy emitted in its operation as a heatlng or cooking stove.
~ 1 ~L~ 8~3~
A device here described comprises heat-transfer means linking its reservoir with a solar collector and its thermal load, the heat-transfer means including a partly liquid-filled conduit or heat pipe which has one of its ends disposed in heat-exchanging S relationship with the reservoir and its other end disposed in heat-exchangingrelationship with the load for transmitting thermal energ~ thereto in a heat-emitting position wherein that conduit is inclined to the horizontal at such an angle that the first-mentioned end lies at a level lower than that of the other end.
As is well known in the art, e.g. from the aforementioned U~ S. patent No. 4,267,825, the liquid partly filling the conduit referred to (which could be water but preferably is a fluid of lower melting point) is vaporized by a heat source at its lower end, the vapors rising to the upper end where they are condensed by an adjoining heat sink so that the heat carrier returns to the source in liquid form. The minimum angle of inclination of the conduit to the horizontal is usually about 6 or 7 degrees;
heat cannot be transmitted from the upper end to the lower one.
This property of one-way heat transfer is utilized, in accordance with a more particular feature of our invention, to minimize losses of stored thermal energy during idle periods in which heat is neither accumulated nor withdrawn. In a simple embodiment, in which one and the same conduit is used for -the transfer of thermal energy from the collector to the reservoir in a heat-absorbing position and from the reservoir to the load
- 2 -13~32 ~LZ~89;2~
in a heat-emittlng position, the collector and the load adjoin each other so as to be both in heat-exchanging relationship with the proximal end of that conduit. Depending on whether this end lies at a lower or a higher level than the end in con-tact with the reservoir, heat ~Jill travel either from the col-lector to the reservoir or from the reservoir to the load. In the latter position, some of the stored heat will also be use-lessly radiated into space by the collector which constitutes an element distinct from the thermal load, this loss can be minimized with the aid of a suitable heat shield covering the working surface of the collector in that position as more fully described hereinafter.
According to another simple embodimen,t requiring but a single conduit, the load is integrated with the reservoir so as to be directly heated thereby. In order to minimize wasteful heat emission during periods of absorption or idleness, we prefer to cover the load with a removable heat shield during such per-iods~ The load, in that instance, may be designed as a substanti-ally horizontal heating plate forming an upper boundary of the ~0 heat reservoir. The plate, in fact, may be provided with one or more dished formations to be used directly as cooking vessels for a more efficient heat transfer.
In a more elaborate embodiment of our invention, different pipes are used to transfer heat from the reservoir to the load and from the collector to tne reservoir, respectively. The first pipe, which corresponds to the heat-transfer conduit discussed above, diverges angularly from the second pipe, i.e. from the one linking the collector with the reservoir, in a heat-absorbing ``` ~L2~
position in which thermal energy is to travel from the collector to the reservoir. This second pipe rises inclinedly toward that reservoir while the firs-t pipe preferably slopes down from the reservoir to the load at an angle to the horizontal which is of opposite sign to and of lesser magnitude than the rise angle of the second pipe. This enables the collector, the reservoir and the load to be constructed as a unit which can be bodily tilted by not more than the rise angle of the second pipe into its heat--emitting position in which the first pipe slopes upward toward the load while the second pipe is at most horizontal so as to prevent a return of thermal energy to the collector. More gener-ally, the angle of inclination of the first pipe can be made adjustable in order to vary the rate of heat transfer between the reservoir and the load in the heat-emitting position; this could be accomplished by a swivelable mounting of that first pipe, through the provision of several differently inclined sockets into which that pipe can be selectively inserted, or by a change in the tilt of the aforementioned unit. In some instances it may also be convenient to have several thermal loads, e.g. heat-ing or cooking plates, connected with the reservoir via respec-tive heat-transfer pipes inclined at different angles; in that case, of course, means would have to be provided for selectively covering or otherwise deactivating the load or loads other than the one desired to be used.
Embodiments of our invention will now be described in detail with reference -to the accompanying drawings in which:
FIG. lA is a cross-sectional view of a device embodying our invention shown in a heat-absorbing position;
FIG. lB is an elevational view, partly in section, show-ing the device of FIG. lA in a heat-emitting position;
FIG. 2 is a view similar to that of FIG. lA, illustrating another embodiment;
FIGS. 3A and 3B are views respectively similar to FIGS. lA
; andlB, showing yet another device embodying our invention in a heat-absorbing and a heat-emitting position, respectively;
FIG. 4 is a fragmentary side-elevational view illustrating a modification of the device oF FIGs 3A and 3B; and FIG. 5 is a fragmentary sectional view illustrating another modification of that device.
Specific Description The device 1 shown in FIGS. lA and lB comprises a solar ; collector 2 of conventional type including, for example, a flat glass panel (or a plurality of such panels) with an evacuated internal space bounded by a blackened heat-absorbing inner sur-face 2'. In the position of FIG. lA, in which the working sur-face of the collector 2 is at the top for irradiation by incident sunlight, the absorbing surface 2' is located at the bottom of the evacuated space and overlies a meandering or coiled extension 4' of a heat pipe 4 rising at an angle of at least 7 into a heat reservoir 3 filled with brine or other heat-storing liquid.
;~ Solid substances are also available for such storage. Fins 8 at the upper end of conduit 4 serve for an effective heat trans-fer between the contents of that conduit, i.e. a vaporizable ~4~
13~-liquid, and the contents of reservoir 3. A thermal load, cGn-stituted by a heating or cooking plate 5, is also in contact with the coiled extensi.on 4' of pipe 4 and has a working surface opposite that of collector 2. The assembly of elements 2 - 5 is enveloped, except at the aforementioned working surfaces, by thermal insulation 7.
The underside of the thermally insulated heat reservoir 3, as viewed in the heat-absorbing position of FIG. lA, is coplanar : with the working surface of plate 5 whereby the entire unit can rest flat on a support 20. When the device is to be used for cooking or space heating, the unit is inverted by 180 as illu-~ strated in FIG. lB whereby plate 5 becomes accessible and collec-;~ tor 2 faces downward. In this heat-emitting position, in which thermal energy stored in reservoir 3 is transmitted via conduit , 15 4 to plate 5, some of that energy unavoidably goes also to col-: lector 2. In order to minimize the heat l~oss through that collec-.~ tor, we prefer to provide the device with a heat shield 6 in the form of a prismatic pad interposable in the position of FIG. lB
between the collector 2 and the supDort 20, this pad will also stabilize the unit in the latter position. I the support 20 is not of sufficiently heat-insulating character, the pad 6 (or a similar heat shield) could also be placed beneath the plate 5 in the heat-absorbing position of FIG. lA, in that case, for the sake of stability, the reservoir 3 would also have to be elevated above support 20 by a suitable insert or possibly by an exten-sible foot as shown, for example, in FIGS. 3A and 3B described hereinafter.
~ Solar collectors of the type described can be designed to : operate with a heat-absorbing capacity ranging between about 200 138~ ~2~
and 400 W/~ and with no-load temperatures between about 470 and 530 K or 100~ and 160~C. Reference may also be made to U. S. patent No. 4,150,657 disclosing a solar collector whose heat-absorbing panel is integral with underlying fluid-conduc-tlng conduits.
In FIG. 2 we have illustrated a modified device 101 wherein the thermal load 5, juxtaposed with collector 2 in the preceding embodiment, has been replaced by an upper wall 105 of a heat reservoir 103 which in the heat-absorbing phase is cover-ed by a heat shield 9 of poor thermal conductivity. Plate 105 can be used directly as a cooking stove, being formed for this purpose with several dished depressions 105', 105" of different depth and volume. As further shown in FIG. 2, reservoir 103 is provided wi.th an undercarriage 12 having wheels or rollers 13 . .15 which facilitate the transportation of the~unit on support 20 in the manner of a wheelbarrow.
Such a wheeled undercarriage 12, 13 is also provided on the heat reservoir 3 of a device 201 illustrated in FIGS. 3A
and 3B. 'rhe thermal load in this instance is a plate 205 sepa-rated from both the collector 2 and the reservoir 3 while being linked with the latter through another heat pipe 10. In the heat-absorbing position of FIG. 3A, pipes 4 and 10 rise toward the reservoir 3 at respective angles of inclination +~ and -~, with~¦considerably smaller than 1~1 ~ In that position, therefore, heat stored in reservoir 3 cannot flow back to either collector 2 or load 205. When the unit 2 - 4, 10 and 205 is tilted about its wheel base into a heat-emittinq position as illustrated in FIG. 3B
the incl.ination of pipe 10 is reversed so that thermal energy can ~L~ 8~3~
now flow from reservoir 3 toward plate 205 for emission as radiant heat or for the cooking of foods placed on that substantially horizontal plate. Pipe 4, however, s-till slopes upwardly toward reservoir 3 at a positive rise angle (or is at most horizontal) so that heat cannot escape via collector 2.
In order to maintain the collector in its elevated position shown in FIG. 3B, a foot 11 articulated thereto at 11' is used for propping it against the support 20. Foot 11 is representative of a variety of retractable bracing means including, for example, a telescoped prop as shown in FIG. 4. The latter prop, which could be duplicated on opposite sides of collector 2, comprises a cyl-inder 18 from which a multisection piston 19 is fluidically exten-sible under the control of apressure regulator 17 responsive to an output signal from a temperature sensor 15 connected thereto via a cable 16. Sensor 15, secured to load 205 so as -to detect its temperature, may be a thermostat of the usual bimetallic type ~ which commands the regulator 17 to lower the collector 2 when that ; temperature exceeds a certain threshold, thereby reducing the rate of heat extraction from reservoir 3. It is, of course, also possible to make the effective length of the prop manually adjust-able for varying the emitted heat.
Heat emission from the load can also be adjusted by a pivotal mounting of pipe 10 in the manner described in the afore-mentioned U. S. patent No. 4,267,825. Such a complex mounting, on the other hand, could be avoided by providing the reservoir 3 and its insulating envelope 7 with severeal apertures of sockets 21, 22 inclined at different angles to the horizontal in both the heat-absorbing and the heat-emitting position of FIGS. 3A
~2qL~
1383~
and 3B. With pipe 21 selectively insertable into the reservoir via any of these sockets, those not used ought to be closed by plugs as indicated at 14. In that instance, furthermore, it is no longer necessary to observe the angular relationship described with reference to FIG. 3A since all the apertures can be plugged in the heat-absorbing position to prevent losses of thermal energy through the load.
It is also possible to provide the device 201 with a plur-ality of loads 205 permanently connected with reservoir 3 via respective heat pipes all having negative angles of inclination, differing among one another, in the position of FIG. 3A. Therm-ally insulating aps or covers, similar to the heat shield 9 of FIG. 2, could then be attached to any load not being utilized ; -- e.g. for cooking purposes -- in the heat-emitting position.
Although the thermal loads 5 and 205 have been illustrated as simple flat plates, they could be provided with removable radiating attachments to improve their effectiveness as space heaters.
A device according to our invention is particularly useful in tropical or subtropical regions where a lot of solar energy is available in daytime but where cooler temperatures at night may require heating aside from cooking. h~e have found that a heat reservoir of moderate dimensions can readily store 4 to 5 kWh of thermal energy which, with about 1 kWh needed in the 2$ preparation of a meal for one person, would cover the cooking requirements of a family of four.
. ~ .
in a heat-emittlng position, the collector and the load adjoin each other so as to be both in heat-exchanging relationship with the proximal end of that conduit. Depending on whether this end lies at a lower or a higher level than the end in con-tact with the reservoir, heat ~Jill travel either from the col-lector to the reservoir or from the reservoir to the load. In the latter position, some of the stored heat will also be use-lessly radiated into space by the collector which constitutes an element distinct from the thermal load, this loss can be minimized with the aid of a suitable heat shield covering the working surface of the collector in that position as more fully described hereinafter.
According to another simple embodimen,t requiring but a single conduit, the load is integrated with the reservoir so as to be directly heated thereby. In order to minimize wasteful heat emission during periods of absorption or idleness, we prefer to cover the load with a removable heat shield during such per-iods~ The load, in that instance, may be designed as a substanti-ally horizontal heating plate forming an upper boundary of the ~0 heat reservoir. The plate, in fact, may be provided with one or more dished formations to be used directly as cooking vessels for a more efficient heat transfer.
In a more elaborate embodiment of our invention, different pipes are used to transfer heat from the reservoir to the load and from the collector to tne reservoir, respectively. The first pipe, which corresponds to the heat-transfer conduit discussed above, diverges angularly from the second pipe, i.e. from the one linking the collector with the reservoir, in a heat-absorbing ``` ~L2~
position in which thermal energy is to travel from the collector to the reservoir. This second pipe rises inclinedly toward that reservoir while the firs-t pipe preferably slopes down from the reservoir to the load at an angle to the horizontal which is of opposite sign to and of lesser magnitude than the rise angle of the second pipe. This enables the collector, the reservoir and the load to be constructed as a unit which can be bodily tilted by not more than the rise angle of the second pipe into its heat--emitting position in which the first pipe slopes upward toward the load while the second pipe is at most horizontal so as to prevent a return of thermal energy to the collector. More gener-ally, the angle of inclination of the first pipe can be made adjustable in order to vary the rate of heat transfer between the reservoir and the load in the heat-emitting position; this could be accomplished by a swivelable mounting of that first pipe, through the provision of several differently inclined sockets into which that pipe can be selectively inserted, or by a change in the tilt of the aforementioned unit. In some instances it may also be convenient to have several thermal loads, e.g. heat-ing or cooking plates, connected with the reservoir via respec-tive heat-transfer pipes inclined at different angles; in that case, of course, means would have to be provided for selectively covering or otherwise deactivating the load or loads other than the one desired to be used.
Embodiments of our invention will now be described in detail with reference -to the accompanying drawings in which:
FIG. lA is a cross-sectional view of a device embodying our invention shown in a heat-absorbing position;
FIG. lB is an elevational view, partly in section, show-ing the device of FIG. lA in a heat-emitting position;
FIG. 2 is a view similar to that of FIG. lA, illustrating another embodiment;
FIGS. 3A and 3B are views respectively similar to FIGS. lA
; andlB, showing yet another device embodying our invention in a heat-absorbing and a heat-emitting position, respectively;
FIG. 4 is a fragmentary side-elevational view illustrating a modification of the device oF FIGs 3A and 3B; and FIG. 5 is a fragmentary sectional view illustrating another modification of that device.
Specific Description The device 1 shown in FIGS. lA and lB comprises a solar ; collector 2 of conventional type including, for example, a flat glass panel (or a plurality of such panels) with an evacuated internal space bounded by a blackened heat-absorbing inner sur-face 2'. In the position of FIG. lA, in which the working sur-face of the collector 2 is at the top for irradiation by incident sunlight, the absorbing surface 2' is located at the bottom of the evacuated space and overlies a meandering or coiled extension 4' of a heat pipe 4 rising at an angle of at least 7 into a heat reservoir 3 filled with brine or other heat-storing liquid.
;~ Solid substances are also available for such storage. Fins 8 at the upper end of conduit 4 serve for an effective heat trans-fer between the contents of that conduit, i.e. a vaporizable ~4~
13~-liquid, and the contents of reservoir 3. A thermal load, cGn-stituted by a heating or cooking plate 5, is also in contact with the coiled extensi.on 4' of pipe 4 and has a working surface opposite that of collector 2. The assembly of elements 2 - 5 is enveloped, except at the aforementioned working surfaces, by thermal insulation 7.
The underside of the thermally insulated heat reservoir 3, as viewed in the heat-absorbing position of FIG. lA, is coplanar : with the working surface of plate 5 whereby the entire unit can rest flat on a support 20. When the device is to be used for cooking or space heating, the unit is inverted by 180 as illu-~ strated in FIG. lB whereby plate 5 becomes accessible and collec-;~ tor 2 faces downward. In this heat-emitting position, in which thermal energy stored in reservoir 3 is transmitted via conduit , 15 4 to plate 5, some of that energy unavoidably goes also to col-: lector 2. In order to minimize the heat l~oss through that collec-.~ tor, we prefer to provide the device with a heat shield 6 in the form of a prismatic pad interposable in the position of FIG. lB
between the collector 2 and the supDort 20, this pad will also stabilize the unit in the latter position. I the support 20 is not of sufficiently heat-insulating character, the pad 6 (or a similar heat shield) could also be placed beneath the plate 5 in the heat-absorbing position of FIG. lA, in that case, for the sake of stability, the reservoir 3 would also have to be elevated above support 20 by a suitable insert or possibly by an exten-sible foot as shown, for example, in FIGS. 3A and 3B described hereinafter.
~ Solar collectors of the type described can be designed to : operate with a heat-absorbing capacity ranging between about 200 138~ ~2~
and 400 W/~ and with no-load temperatures between about 470 and 530 K or 100~ and 160~C. Reference may also be made to U. S. patent No. 4,150,657 disclosing a solar collector whose heat-absorbing panel is integral with underlying fluid-conduc-tlng conduits.
In FIG. 2 we have illustrated a modified device 101 wherein the thermal load 5, juxtaposed with collector 2 in the preceding embodiment, has been replaced by an upper wall 105 of a heat reservoir 103 which in the heat-absorbing phase is cover-ed by a heat shield 9 of poor thermal conductivity. Plate 105 can be used directly as a cooking stove, being formed for this purpose with several dished depressions 105', 105" of different depth and volume. As further shown in FIG. 2, reservoir 103 is provided wi.th an undercarriage 12 having wheels or rollers 13 . .15 which facilitate the transportation of the~unit on support 20 in the manner of a wheelbarrow.
Such a wheeled undercarriage 12, 13 is also provided on the heat reservoir 3 of a device 201 illustrated in FIGS. 3A
and 3B. 'rhe thermal load in this instance is a plate 205 sepa-rated from both the collector 2 and the reservoir 3 while being linked with the latter through another heat pipe 10. In the heat-absorbing position of FIG. 3A, pipes 4 and 10 rise toward the reservoir 3 at respective angles of inclination +~ and -~, with~¦considerably smaller than 1~1 ~ In that position, therefore, heat stored in reservoir 3 cannot flow back to either collector 2 or load 205. When the unit 2 - 4, 10 and 205 is tilted about its wheel base into a heat-emittinq position as illustrated in FIG. 3B
the incl.ination of pipe 10 is reversed so that thermal energy can ~L~ 8~3~
now flow from reservoir 3 toward plate 205 for emission as radiant heat or for the cooking of foods placed on that substantially horizontal plate. Pipe 4, however, s-till slopes upwardly toward reservoir 3 at a positive rise angle (or is at most horizontal) so that heat cannot escape via collector 2.
In order to maintain the collector in its elevated position shown in FIG. 3B, a foot 11 articulated thereto at 11' is used for propping it against the support 20. Foot 11 is representative of a variety of retractable bracing means including, for example, a telescoped prop as shown in FIG. 4. The latter prop, which could be duplicated on opposite sides of collector 2, comprises a cyl-inder 18 from which a multisection piston 19 is fluidically exten-sible under the control of apressure regulator 17 responsive to an output signal from a temperature sensor 15 connected thereto via a cable 16. Sensor 15, secured to load 205 so as -to detect its temperature, may be a thermostat of the usual bimetallic type ~ which commands the regulator 17 to lower the collector 2 when that ; temperature exceeds a certain threshold, thereby reducing the rate of heat extraction from reservoir 3. It is, of course, also possible to make the effective length of the prop manually adjust-able for varying the emitted heat.
Heat emission from the load can also be adjusted by a pivotal mounting of pipe 10 in the manner described in the afore-mentioned U. S. patent No. 4,267,825. Such a complex mounting, on the other hand, could be avoided by providing the reservoir 3 and its insulating envelope 7 with severeal apertures of sockets 21, 22 inclined at different angles to the horizontal in both the heat-absorbing and the heat-emitting position of FIGS. 3A
~2qL~
1383~
and 3B. With pipe 21 selectively insertable into the reservoir via any of these sockets, those not used ought to be closed by plugs as indicated at 14. In that instance, furthermore, it is no longer necessary to observe the angular relationship described with reference to FIG. 3A since all the apertures can be plugged in the heat-absorbing position to prevent losses of thermal energy through the load.
It is also possible to provide the device 201 with a plur-ality of loads 205 permanently connected with reservoir 3 via respective heat pipes all having negative angles of inclination, differing among one another, in the position of FIG. 3A. Therm-ally insulating aps or covers, similar to the heat shield 9 of FIG. 2, could then be attached to any load not being utilized ; -- e.g. for cooking purposes -- in the heat-emitting position.
Although the thermal loads 5 and 205 have been illustrated as simple flat plates, they could be provided with removable radiating attachments to improve their effectiveness as space heaters.
A device according to our invention is particularly useful in tropical or subtropical regions where a lot of solar energy is available in daytime but where cooler temperatures at night may require heating aside from cooking. h~e have found that a heat reservoir of moderate dimensions can readily store 4 to 5 kWh of thermal energy which, with about 1 kWh needed in the 2$ preparation of a meal for one person, would cover the cooking requirements of a family of four.
. ~ .
Claims (9)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for the utilization of solar heat, comprising:
a solar collector for heat absorption;
an insulated heat storage block; and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit;
a heat emission means in direct thermal connection with said solar collector, adapted to be connected to said heat storage block by way of said heat pipe means, thermal energy from said heat storage block being transmissible to said heat emission means in a heat emitting position wherein said heat pipe is positioned to extend upwardly from said heat storage block towards said heat emission means, said unit being changeable from the heat absorbing position to the heat emitting position by physical inversion.
a solar collector for heat absorption;
an insulated heat storage block; and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit;
a heat emission means in direct thermal connection with said solar collector, adapted to be connected to said heat storage block by way of said heat pipe means, thermal energy from said heat storage block being transmissible to said heat emission means in a heat emitting position wherein said heat pipe is positioned to extend upwardly from said heat storage block towards said heat emission means, said unit being changeable from the heat absorbing position to the heat emitting position by physical inversion.
2. The device as claimed in claim 1, including a heat-insulation element, said heat emission means being coverable with said heat-insulation element in the heat absorbing position, and said solar collector being coverable with said heat-insulation element in said heat emitting position.
3. A device for the utilization of solar heat, comprising:
a solar collector for heat absorption;
a heat storage block: and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit:
a heat emission means in direct thermal connection with said heat storage block a removable insulating cover plate for said heat storage block, said heat emission means being located beneath said removable cover.
a solar collector for heat absorption;
a heat storage block: and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit:
a heat emission means in direct thermal connection with said heat storage block a removable insulating cover plate for said heat storage block, said heat emission means being located beneath said removable cover.
4. A device for the utilization of solar heat, comprising:
a solar collector for heat absorption;
an insulated heat storage block; and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block and for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit:
a heat emission means connected to said heat storage block by way of an additional heat pipe, thermal energy from said heat storage block being transmissible to said heat emission means in a heat emitting position wherein said additional heat pipe is positioned to extend upwardly from said heat storage block towards said heat emission means, the angle of elevation of said additional heat pipe connecting said heat emission means with said heat storage block being less than the angle of elevation of the first mentioned heat pipe connecting said solar collector with said heat storage block, and wherein for changing over from the heat absorbing position to the heat emitting position said unit is tilled up by raising said solar collector with respect to said heat storage block through an angle not more than the angle of elevation of said first mentioned heat pipe.
a solar collector for heat absorption;
an insulated heat storage block; and a heat pipe means with at least one heat pipe connecting said solar collector with said heat storage block and for transmitting thermal energy from said solar collector to said heat storage block in a heat absorbing position in which said heat pipe is positioned to extend upwardly from said solar collector towards said heat storage block; said collector, said storage block and said heat pipe means being arranged in a fixed spatial relationship as a unit:
a heat emission means connected to said heat storage block by way of an additional heat pipe, thermal energy from said heat storage block being transmissible to said heat emission means in a heat emitting position wherein said additional heat pipe is positioned to extend upwardly from said heat storage block towards said heat emission means, the angle of elevation of said additional heat pipe connecting said heat emission means with said heat storage block being less than the angle of elevation of the first mentioned heat pipe connecting said solar collector with said heat storage block, and wherein for changing over from the heat absorbing position to the heat emitting position said unit is tilled up by raising said solar collector with respect to said heat storage block through an angle not more than the angle of elevation of said first mentioned heat pipe.
5. The device as claimed in claim 3, wherein said solar collector is provided with a fold-out support foot of chosen length.
6. The device as claimed in claim 3, wherein said heat storage block is provided with a support foot adapted for receiving a roller caster thereon.
7. The device as claimed in claim 4, wherein said solar collector is provided with a fold-out support foot of chosen length.
8. The device as claimed in claim 4, wherein said heat storage block is provided with a support foot which is adapted for receiving a roller caster thereon.
9. The device as claimed in claim 5, wherein said heat storage block is provided with a support foot which is adapted for receiving a roller caster thereon.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3226782.7 | 1982-07-17 | ||
| DE3226782A DE3226782C2 (en) | 1982-07-17 | 1982-07-17 | Heating and / or cooking device with a solar collector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1240892A true CA1240892A (en) | 1988-08-23 |
Family
ID=6168658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000421860A Expired CA1240892A (en) | 1982-07-17 | 1983-02-17 | Heating and/or cooking device using solar energy |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0099423B1 (en) |
| JP (1) | JPS5914830A (en) |
| AT (1) | ATE24962T1 (en) |
| AU (1) | AU567866B2 (en) |
| BR (1) | BR8300353A (en) |
| CA (1) | CA1240892A (en) |
| DE (2) | DE3226782C2 (en) |
| ES (1) | ES517529A0 (en) |
| GR (1) | GR77377B (en) |
| IN (1) | IN155654B (en) |
| NZ (1) | NZ203081A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3521027A1 (en) * | 1985-06-12 | 1986-12-18 | Walter 2000 Hamburg Müller | Electrically heated or solar-heated cooker with heat accumulator |
| DE3528779A1 (en) * | 1985-08-10 | 1987-02-19 | Otmato Ag | STOVE POWERED BY SOLAR ENERGY |
| DE3544039A1 (en) * | 1985-11-08 | 1987-05-27 | Erich Poehlmann | HEATING AND / OR COOKING DEVICE WITH A HEAT STORAGE BLOCK |
| DE3542011A1 (en) * | 1985-11-28 | 1987-06-04 | Grotjan Hartmut | Device for heat recovery from in particular spatially extensive heat sources |
| DE4338736A1 (en) * | 1993-11-12 | 1995-05-24 | Arnold Prof Dip Wietrzichowski | Solar powered cooker and/or heater with heat energy storage |
| AU688392B2 (en) * | 1993-11-22 | 1998-03-12 | Technisearch Ltd. | Solar-powered hot water systems |
| CA2672760C (en) * | 2009-07-23 | 2017-10-17 | Huazi Lin | Solar coffee/tea maker and cooking appliances |
| CA2673703C (en) * | 2009-07-23 | 2015-05-05 | Huazi Lin | Solar cooking appliances |
| FR2954818A1 (en) * | 2009-12-29 | 2011-07-01 | C3Tech | Stored solar thermal energy generator for generating thermal energy to cook food in e.g. desert, has coaxial tank provided with heat insulator, where solar energy is stored and restored by two exothermic and endothermic reactions |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3643648A (en) | 1970-08-21 | 1972-02-22 | Adnan S Tarcici | Solar heating devices |
| DE2402999A1 (en) * | 1974-01-23 | 1975-07-31 | Rhein Westfael Elect Werk Ag | Solar heat utilisation plant - has heat collector with intermediate heat carrier led to heat exchanger |
| JPS51134965A (en) * | 1975-05-19 | 1976-11-22 | Okuma Howa Kikai Kk | Heat recovering device |
| JPS5525786A (en) * | 1978-08-16 | 1980-02-23 | Babcock Hitachi Kk | Energy trapper |
| US4267825A (en) * | 1979-06-27 | 1981-05-19 | Entec Products Corporation | Solar heat collector with heat pipes |
| DE3011254A1 (en) * | 1980-03-24 | 1981-10-01 | Hubert 5010 Bergheim Herpers | Energy converter and solar heat collector - has large surface area with fins forming wind passages |
| DE3033123A1 (en) * | 1980-09-03 | 1982-04-08 | Antonius 2945 Sande Pollmann | Solar-heated cooking pan - has black energy-absorbing lid with conductor pins or plates leading to inside insulated pan |
| DE3044192A1 (en) * | 1980-11-24 | 1982-06-03 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München | Solar energy utilising cooker - incorporates one or more solar radiation concentrators |
| US4438759A (en) * | 1980-12-24 | 1984-03-27 | Matsushita Electric Industrial Co., Ltd. | Heat-pipe type solar water heater |
| DE3120520C2 (en) * | 1981-05-22 | 1984-05-24 | Erich 8650 Kulmbach Pöhlmann | Heating device with a solar collector |
-
1982
- 1982-07-17 DE DE3226782A patent/DE3226782C2/en not_active Expired
- 1982-10-28 AT AT82109980T patent/ATE24962T1/en not_active IP Right Cessation
- 1982-10-28 EP EP82109980A patent/EP0099423B1/en not_active Expired
- 1982-10-28 DE DE8282109980T patent/DE3275119D1/en not_active Expired
- 1982-11-03 GR GR69709A patent/GR77377B/el unknown
- 1982-11-19 ES ES517529A patent/ES517529A0/en active Granted
-
1983
- 1983-01-24 IN IN93/CAL/83A patent/IN155654B/en unknown
- 1983-01-24 AU AU10702/83A patent/AU567866B2/en not_active Ceased
- 1983-01-24 JP JP58008833A patent/JPS5914830A/en active Pending
- 1983-01-25 NZ NZ203081A patent/NZ203081A/en unknown
- 1983-01-25 BR BR8300353A patent/BR8300353A/en unknown
- 1983-02-17 CA CA000421860A patent/CA1240892A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ATE24962T1 (en) | 1987-01-15 |
| AU567866B2 (en) | 1987-12-10 |
| DE3226782C2 (en) | 1984-10-25 |
| BR8300353A (en) | 1984-05-02 |
| GR77377B (en) | 1984-09-11 |
| DE3275119D1 (en) | 1987-02-19 |
| EP0099423A2 (en) | 1984-02-01 |
| EP0099423B1 (en) | 1987-01-14 |
| EP0099423A3 (en) | 1984-08-01 |
| ES8308038A1 (en) | 1983-08-16 |
| NZ203081A (en) | 1986-06-11 |
| AU1070283A (en) | 1984-01-19 |
| ES517529A0 (en) | 1983-08-16 |
| IN155654B (en) | 1985-02-16 |
| JPS5914830A (en) | 1984-01-25 |
| DE3226782A1 (en) | 1984-01-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |