AU2009301361B2

AU2009301361B2 - Device for absorbing electromagnetic radiation

Info

Publication number: AU2009301361B2
Application number: AU2009301361A
Authority: AU
Inventors: Roland Kuffer
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-09
Filing date: 2009-10-08
Publication date: 2014-07-10
Anticipated expiration: 2029-10-08
Also published as: US20110197878A1; WO2010040525A3; DE102008050618B3; ES2468340T3; AU2009301361A1; DK2366083T3; WO2010040525A2; EP2366083A2; PL2366083T3; EP2366083B1

Abstract

The invention relates to a device (3) for absorbing electromagnetic radiation, in particular solar radiation. The device (3) has at least one flexible film pocket (4) that is divided into chambers (15). Said chambers (15) are connected to at least one feed element (5) and at least one discharge element (6), by means of which a heat transfer medium can be fed to and discharged from the chambers (15). To prevent a build-up of pressure in the heat transfer medium caused by gravity and thus unwanted stress on the film material, at least one pressure reducing element (21) is provided between at least two of the chambers (15) or film pockets (4). Said pressure reducing element (21) limits the pressure of the heat transfer medium in the individual chambers.

Description

1 Device for absorbing electromagnetic radiation The invention relates to a device for absorbing electromagnetic radiation, in particular solar radiation. 5 The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of 10 the material referred to was published, known or part of the common general knowledge as at the priority date of the application. DE 32 24 688 Al discloses a solar collector of the type in 15 question which is formed by welded-together sheets of plastic. The sheets of plastic are divided by weld seams into chambers. These chambers can be flowed through by a heat transfer medium in the form of water. For this purpose, the chambers are connected in a communicating manner to a common inlet and a 20 common outlet. This known device has been successfully used for forming solar collectors on flat roofs and is particularly distinguished by its low-cost construction. However, use of such a solar 25 collector on sloping roofs is precluded, since in this case the heat transfer medium separates into layers. In the region of the lower chambers especially, this causes pressures that can no longer be withstood by this sheet type of structure. Consequently, this known solar collector has only a moderate 30 application range. Furthermore, there is the fundamental problem that this known solar collector is usually operated in a closed cycle, allowing unfavorable pressure conditions to occur during operation even in the case of collectors that are lying flat.

2 DE 42 37 228 C2 discloses an absorber for solar collectors that is distinguished by particularly high energy efficiency. For this purpose, the actual absorber is surrounded on the 5 underside and around the periphery by a heat insulating material. On the upper side, facing the sun, there is a vacuum insulation, which is closed off by a window. In this way, good heat insulation is obtained around the absorber, so that this absorber can generate high temperatures in the heat transfer 10 medium even when the ambient air is cold, such as for example in winter. However, it is not possible for this known solar collector to be formed from sheets in accordance with the aforementioned document, since a vacuum insulation cannot be obtained with sheets because of the lack of dimensional 15 stability. DE 27 20 755 Al discloses a further solar collector, which has a radiation-absorbent liquid as a heat transfer medium. This measure is intended in particular to prevent problems of 20 overheating during the operation of the solar collector. DE 88 10 095 Ul discloses an autonomous solar device for providing hot water. The device comprises a thin-walled sheet collector which is connected to a service water line. Since the 25 collector cannot withstand the pressure in the service water line, a pressure reducer is provided between the service water line and the collector. However, this pressure reducer serves exclusively for lowering the pressure in the water line, and consequently cannot limit differences in pressure within the 30 collector system. It is therefore desirable to provide a device that can be used universally while being of a low-cost construction.

2a According to the present invention there is provided a device for absorbing electromagnetic radiation, the device having at least one flexible sheet pocket, which is divided into chambers, which are connected to at least one supply line for 5 introducing a heat transfer medium and at least one discharge line for letting out the heat transfer medium, wherein the device has at least one pressure reducer on the inlet side between at least two of the chambers and/or sheet pockets which limits the pressure of the heat transfer medium. 10 The device serves for absorbing electromagnetic radiation, in particular solar rays. The main intended use of this device is in the area of WO 2010/040525 PCT/EP2009/007226 - 3 solar collectors for the conversion of sunlight into heat. To make the device inexpensive, it has at least one flexible sheet pocket, which is divided into chambers. This sheet pocket is in this case flowed 5 through by a heat transfer medium. The construction in the form of sheets offers the advantage that the device can be transported very easily. In particular, this device can be rolled or folded up. Sheets can be produced at very low cost, since they use only little 10 material. The sheets preferably consist of a polymer material, not only pure polymers but also mixed polymers being suitable for use. Polyvinyl chloride, polyethylene and polyurethane have been found to be particularly successful. To form the sheet pockets, one 15 sheet may be folded over. It is alternatively possible for two sheets to be welded together. Dividing the sheet pocket into chambers allows heat transfer medium to flow uniformly through the sheet pocket and increased stability of the sheet pocket to be achieved. 20 This is important for making optimum use of the sunlight. The division may be obtained by weld seams and/or by spaced-apart weld spots. A silicone oil, which remains well below its boiling point under operating conditions, is preferably used as the heat 25 transfer medium. In this way, increases in pressure caused by boiling effects in the heat transfer medium are reliably avoided. For supplying and discharging the heat transfer medium, the sheet pocket has at least one inlet and at least one outlet. These communicate with 30 the chambers of the sheet pocket. If the sheet pockets described are laid on a sloping roof, there is the fundamental problem that different pressures are obtained within the sheet pocket. In 35 particular, owing to gravity, a much greater pressure is obtained in the region of the lower end of the roof than in the region of the ridge, which leads to considerable pressure loading and stressing of the 4 sheet pocket in the lower region. In principle, this situation could be counteracted by forming the sheet pocket with correspondingly thick walls. However, this measure is contrary to the stated desired outcome of the invention. Furthermore, in 5 this way the sheet pocket becomes flexurally more rigid, which makes it considerably more difficult to handle. To solve this problem, at least one pressure reducer is provided on the inlet side between at least two of the chambers 10 or sheet pockets and reduces the pressure of the heat transfer medium in the chamber. This measure appears to be contrary to the stated object, since the pressure reducers do in fact represent a considerable cost factor. For example, a roof height of 3 m and a maximum pressure of the heat transfer 15 medium of 2 kPa would require an arrangement of at least 14 pressure reducers, which makes a significant difference to the cost of the overall installation of the solar collector. However, it must be taken into consideration in this respect that only one pressure reducer is required for each section 20 over the height of the solar collector, since no gravity induced pressure differences can build up in a chamber extending horizontally over the entire length of the roof. Furthermore, the pressure reducers can be of a very simple construction, since the aim is essentially for the heat 25 transfer medium to be transported pressurelessly through the device. In order to prevent pressures from building up between the chambers as a result of the communicating connection on the 30 outlet side, it is advantageous if at least one fluid diode or at least one pressure reducer is provided on the outlet side between at least two chambers or sheet pockets. A fluid diode has a low flow resistance in the preferential direction but a great flow resistance in the opposite direction. This prevents 5 the outlet of a higher-lying chamber being able to force the heat transfer medium out on the outlet side into the chamber lying thereunder. In order to prevent corresponding pressures from being able to build up when the heat transfer medium is 5 stationary, it is enough in this case to provide a sufficiently large storage tank, so that the heat transfer medium can always flow away unhindered. Consequently, the heat transfer medium is only stationary when the chambers are virtually empty. This measure at the same time prevents the device from overheating 10 when the heat transfer medium is stationary. Alternatively, a pressure reducer may also be provided on the outlet side and reliably exclude the possibility of excessive pressures occurring. These pressure reducers also work when the heat transfer medium is stationary. 15 A simple way of creating the pressure reducer is in the form of a section of pipe with foam or fibrous material inserted in it. This material provides the corresponding flow resistance, so that no pressures can build up. The foam or the fibrous 20 material is preferably dimensioned in such a way that it has a capillary effect. Alternatively or in addition, the pressure reducer may be formed by a drip chamber. This drip chamber interrupts the 25 communicating connection between the individual chambers, so that no pressures can build up from one chamber to the next. Alternatively or in addition, the pressure reducer may also be formed by a section of pipe with rungs running transversely in 30 relation to the direction of flow. These rungs produce a cascade, which likewise has a pressure-reducing effect.

6 It is advantageous if the pressure reducer is formed by at least one meander, which likewise has a pressure-reducing effect by increasing the length of the line. 5 To achieve a high final temperature of the heat transfer medium, it is important to keep heat losses as low as possible. The main heat loss of a solar collector is formed by the conduction of heat into the ambient air. This heat conduction becomes all the greater the cooler the ambient air is. However, 10 it is particularly when the ambient air is cold that the greatest heating power is required. It is therefore expedient to keep down this loss mechanism. It is proposed, for this purpose, to cover at least the underside of the sheet with at least one heat insulator. The underside of the sheet has no 15 radiation coupling-in function and can therefore be thermally insulated in any way desired. However, the underside of the sheet has a large surface area in relation to the end faces, and therefore contributes considerably to the heat loss. For this reason, insulation of the underside of the sheet is 20 particularly effective. Apart from that, it is expedient also to insulate additionally the end faces of the sheet pocket. To obtain a further increase in the final temperature of the heat transfer medium, it is advantageous if the sheet pockets 25 are covered with a heat insulation, at least on the upper side. The insulation of the upper side is particularly expedient because this side is exposed directly to the ambient air. In addition, winds can also blow along the upper side of the sheet pocket and these winds can lead to an increased loss of heat. 30 In order on the other hand not to impair the radiation absorption too much, however, it is important in the case of insulation on the upper side to form it from a transparent heat insulator.

7 Heat insulating materials that are often used are sensitive to wet and lose a considerable part of their insulating effect in the wet state. For this reason, it is favorable if the heat insulator is surrounded by a protective film. This protective 5 film essentially has the task of keeping wet, especially rain, away from the heat insulation. To obtain a further improvement in the insulating effect, it is favorable if the protective film is gas-filled. This has the 10 effect that the protective film lifts off slightly from the heat insulation, so that the protective film acts like a greenhouse. In addition, good protection from hail is obtained in this way. 15 As a simple way of creating the chambers and the inlet and outlet, it is advantageous to structure the sheet pocket by means of weld seams. In particular, these weld seams can be produced on a running web of sheet, which makes production particularly inexpensive. 20 It is considered in principle to make the side of the sheet pockets that is facing the radiation source transparent and to color the side facing away black. This achieves the effect that the electromagnetic radiation penetrates through the facing 25 sheet and is absorbed by the sheet facing away. The heat produced in this way in the sheet is then transferred to the heat transfer medium. It is more favorable to form the heat transfer medium itself as radiation-absorbent. This also brings into consideration, along with the configuration described 30 above of the sheet pockets, an alternative in which, for example, both sides of the sheet pocket are transparently formed. The use of a radiation-absorbent heat transfer medium means that the heat is generated directly in the heat transfer medium, so that heat conduction between the absorber surface 8 and the heat transfer medium is no longer required. In this case, the absorption of the device can also be controlled. If, for example, a circulating pump for the heat transfer medium fails, there is in principle the risk of the heat transfer 5 medium overheating, which could lead to the sheet becoming damaged. If it is provided that the heat transfer medium can in this case flow out of the sheet pocket unhindered, the system regulates itself to the extent that, in the event of failure of the circulating pump, the absorptivity of the device is also 10 reduced. In this case, the device protects itself from overheating. In order to shorten the response time of the overheating protection, it is favorable to use a heat transfer medium with 15 temperature-dependent radiation absorption. In this case, as the temperature increases, the absorption of the heat transfer medium decreases, possibly abruptly. In the case of imminent overheating of the heat transfer medium, for example if the circulating pump is at a standstill, the radiation absorption 20 is reduced in this way, since the heat transfer medium becomes increasingly more transparent. This, however, also reduces the energy input into the heat transfer medium, which prevents overheating. 25 It is favorable to make the sheet pocket or the protective film UV-resistant or gnaw-proof. Conventional UV stabilizers are used for this. It is additionally considered to incorporate odorous substances in the polymer, which deter animals that could bite into the sheet. Examples of such animals are martens 30 and raccoons. To improve the energy yield, it is advantageous if the sheet pocket or the protective film has at least one photovoltaic cell of semiconducting material. This allows part of the 9 sunlight to be converted directly into electrical energy, while the portion of the solar energy that cannot be used for this is converted into heat. This portion then serves for heating up the heat transfer medium, to allow it in this way to be put to 5 further use. In this way, a favorable synergistic effect is obtained, since the heat transfer medium cools the photovoltaic cells, and consequently also increases their efficiency. It is advantageous if at least one valve influencing the 10 through-flow of the heat transfer medium or at least one circulating pump is provided in the supply line or discharge line. It is thereby possible in a simple way to set or control the through-flow rate of the heat transfer medium, in order to obtain an adaptation to ambient conditions. In particular, it 15 is considered to increase the through-flow rate of the heat transfer medium when there is strong solar irradiation, in order in this way to obtain more heat. When there is reduced solar irradiation, on the other hand, the through-flow rate of the heat transfer medium is reduced, in order to ensure a 20 sufficiently high temperature level. This valve or this circulating pump is preferably in operative connection with at least one sensor, so that closed-loop control can be achieved in this way. In the simplest case, the temperature of the heat transfer medium in the outlet line is controlled to a value 25 that still makes it possible for the heat to be used for the planned purpose. Alternatively, however, more complex closed loop controls are also conceivable, for example controls which optimize the energy conversion of the overall system. It is also considered to use the at least one sensor to sense when 30 the collector is covered with snow, in order to reverse the heat flow of the heat transfer medium. In this way, when the collector is covered with snow, the heat transfer medium can introduce heat into the collector, in order to melt the snow 10 that is on the collector, so that it can subsequently slide off. Finally, it is favorable if the device is adhesively fixed on a 5 base. This has the advantage of ruling out movement of the device in relation to the base that could lead to abrasion caused by scraping effects, and consequently to destruction of the device. Furthermore, in this case the device can always be mounted in the same way irrespective of the actual form of the 10 roof. In particular, it is not necessary for fastening means to be adapted to the actual form of the roof. The subject matter of the invention is explained by way of example on the basis of the drawing, without restricting the 15 scope of protection. Further advantages and features of the present invention are presented in the following detailed description on the basis of the associated figures, in which a number of exemplary 20 embodiments of the present invention are contained. However, it should be understood that the drawing serves only for the purpose of representing the invention and does not restrict the scope of protection of the invention. 25 In the drawing: Figure 1 shows a schematic representation of a house with a solar collector system, Figure 2 shows a three-dimensional view of a device for 30 absorbing electromagnetic radiation, WO 2010/040525 PCT/EP2009/007226 - 11 Figure 3 shows a sectional representation through the device according to Figure 2 along the sectional line III-III, Figure 4 shows a schematic representation of a first 5 embodiment of a pressure reducer, Figure 5 shows a schematic representation of a second embodiment of a pressure reducer and Figure 6 shows a schematic representation of a third embodiment of a pressure reducer. 10 Figure 1 shows a schematic representation of a house 1 with a roof 2. Fitted on the roof 2 is a device 3 for absorbing solar radiation, which is formed by a number of sheet pockets 4. These sheet pockets 4 are in 15 connection via supply lines 5 and discharge lines 6. The supply line 5 is in this case in connection with a pressure side of a circulating pump 7, which pumps a heat transfer medium from a storage tank 8 into the supply line 5. The discharge line 6, on the other hand, 20 is in connection with a heat exchanger 9, which extracts from the heat transfer medium the heat absorbed, in order to make it usable in the house 1. From the heat exchanger 9, the heat transfer medium returns to the storage tank 8. 25 Installed in the discharge line 6 is a valve 31, which influences the through-flow of the heat transfer medium through the discharge line 6. This valve 31 is in operative connection with a controller 34, which is 30 influenced by sensors 32, 33. The sensor 32 is in this case a pure temperature sensor, which senses the temperature of the heat transfer medium in the discharge line 6. The sensor 33, on the other hand, is a snow sensor, which may, for example, be formed as a 35 light-sensitive sensor and determines whether the sheet pockets 4 are covered with snow. In addition, the controller 34 influences the circulating pump 7 in the sense of reversing the direction of rotation.

WO 2010/040525 PCT/EP2009/007226 - 12 In the simplest case, the controller 34 may effect a temperature control of the heat transfer medium in the discharge line 6. In this case, the flow of the heat 5 transfer medium is controlled in such a way that a constant temperature of the heat transfer medium is obtained at the location of the temperature sensor 32. Furthermore, the controller 34 is influenced by the snow sensor 33, which in the simplest case effects the 10 reversal of the direction of rotation of the circulating pump 7. If snow is covering the sheet pockets 4, in this case the heat transfer medium is reversed in its direction of flow, so that it does not give off heat in the heat exchanger 9 but is heated up 15 in it. This heat is then introduced into the sheet pockets 4, in order to melt the snow lying on them, and thereby restore the function of the device 3. The snow sensor 33 is preferably constructed in such a way that, apart from sensing the thickness of the snow, it also 20 senses snowfall, in order to prevent the sheet pockets 4 from being thawed out the whole time when there is continuous snowfall. This provides increased energy efficiency of the device 3. 25 Figures 2 and 3 show a three-dimensional view of the sheet pocket 4 with shortened longitudinal extent in relation to Figure 1. The sheet pocket 4 comprises an upper sheet 10 and a lower sheet 11. The two sheets 10, 11 are transparent, so that sunlight can penetrate 30 through the entire sheet pocket 4 unhindered. The sheet pocket 4 is provided at the periphery with peripheral weld seams 12, which close the sheet pocket 4 on all sides apart from openings 13 for the supply 35 line 5 and the discharge line 6. In order to be easily able to cascade the sheet pockets 4, the sheet pocket 4 has two openings 13 for the supply line 5 and two openings 13 for the discharge line 6.

WO 2010/040525 PCT/EP2009/007226 - 13 The sheet pocket 4 also has separating weld seams 14, which separate the sheet pocket 4 into individual chambers 15. These chambers 15 are distributed two 5 dimensionally over virtually the entire sheet pocket 4 and are charged via the supply line 5 with a heat transfer medium (not represented), which can flow away via the discharge line 6. Consequently, the heat transfer medium, guided by the separating weld seams 10 14, can essentially only flow through the chambers 15 in the direction of flow 16. Pressure reducers (not represented) may be fitted in the supply line 5 and discharge line 6 from chamber 15 15 to chamber 15. In addition, it is also conceivable to provide a pressure reducer respectively between only a certain number of chambers 15. It is also considered to arrange a pressure reducer respectively between at least two sheet pockets 4 in the region of the supply 20 line 5 and the discharge line 6. In the region of the discharge line 6, a simple fluid diode may be used instead of a pressure reducer. To reduce the losses from heat conduction with the 25 surrounding air, the sheet pocket 4 is surrounded on all sides by a heat insulator 17. This heat insulator 17 is transparent, at least on the upper side, in order to keep reflection of the incident electromagnetic radiation as small as possible. On the underside of the 30 sheet pocket 4, any desired heat insulator 17 may be used. In order to prevent the heat insulator 17 from becoming soaked through, and consequently being restricted in 35 its insulating capability, the entire arrangement is encased in a protective film 18, which in turn is peripherally sealed off by weld seams 19. Distributed in these weld seams 19 are eyelets 20, which allow WO 2010/040525 PCT/EP2009/007226 - 14 simple fastening of the sheet pocket 4 to the roof 2 of the house 1 by lashing. Alternatively or in addition, the sheet pocket 4 may also be adhesively attached to the roof 2. On at least one longitudinal side, the 5 sheet pocket 4 is drawn out until it overlaps with the weld seam 19 and is provided with flush eyelets 20. In this way, the sheet pocket 4 is kept in position within the protective film 18. The drawn-out periphery is preferably located at the higher longitudinal edge. 10 Figure 4 shows a schematic representation of a first embodiment of a pressure reducer 21. The supply line 5 is in connection with a branch line 22, which is led directly into a chamber 15. The supply line 5 is closed 15 at the end by a plate 23, in order to prevent an increasing pressure from building up from chamber 15 to chamber 15 owing to gravity. Arranged in the supply line 5 is a valve 24, which sits 20 on a membrane 25. The membrane 25 is loaded from the outside with air pressure of the ambient air and in this way forms a pressure sensor. On the left side, the membrane 25 is acted upon by the heat transfer medium, so that the valve 24 closes whenever the pressure of 25 the heat transfer medium in a membrane chamber 26 exceeds a specific value. In this way, a defined fluid pressure is obtained in the membrane chamber 26. The membrane chamber 26 is in connection via an opening 27 with the supply line 5 of the following pressure 30 reducer 21. Figure 5 shows an alternative embodiment of a pressure reducer 21. In the case of this embodiment, a supply line 5 with increased cross section is used. Inside the 35 pressure line 5 there is a foam or fibrous material 28, which has capillary effects. This capillary effect excludes the possibility of gravity-induced pressures building up via the supply line 5.

WO 2010/040525 PCT/EP2009/007226 - 15 Finally, Figure 6 shows a further alternative embodiment of a pressure reducer 21. In this case, the supply line 5 has a cross-sectional narrowing 29 at its 5 free end. This cross-sectional narrowing 29 provides a drip system, through which a drip chamber 30 is filled with the heat transfer medium. On account of the drop in height caused by the drip system, the individual branch lines 22 are no longer connected in a 10 communicating manner by the heat transfer medium. Since some exemplary embodiments of the present invention are not shown or described, it should be understood that many changes and modifications to these 15 described exemplary embodiments are possible, without departing from the essential concept and protective scope of the invention that is established by the claims .

WO 2010/040525 PCT/EP2009/007226 - 16 List of designations 1 House 30 Drip chamber 2 Roof 31 Valve 3 Device 32 Temperature sensor 4 Sheet pocket 33 Snow sensor 5 Supply line 34 Controller 6 Discharge line 7 Circulating pump 8 Storage tank 9 Heat exchanger 10 Upper sheet 11 Lower sheet 12 Peripheral weld seam 13 Opening 14 Separating weld seam 15 Chamber 16 Direction of flow 17 Heat insulator 18 Protective film 19 Weld seam 20 Eyelet 21 Pressure reducer 22 Branch line 23 Plate 24 Valve 25 Membrane 26 Membrane chamber 27 Opening 28 Foam or fibrous part 29 Cross-sectional narrowing

Claims

1. A device for absorbing electromagnetic radiation, the device having at least one flexible sheet pocket, which is 5 divided into chambers, which are connected to at least one supply line for introducing a heat transfer medium and at least one discharge line for letting out the heat transfer medium, wherein the device has at least one pressure reducer on the inlet side between at least two of the chambers and/or sheet 10 pockets , which limits the pressure of the heat transfer medium.

2. The device as claimed in claim 1, the electromagnetic radiation being solar radiation. 15

3. The device as claimed in claim 1 or 2, wherein at least one fluid diode and/or at least one pressure reducer is provided on the outlet side between at least two of the chambers and/or sheet pockets. 20

4. The device as claimed in any one of claims 1 to 3, wherein the pressure reducer is formed by a section of pipe into which a foam and/or fibrous material has been inserted. 25

5. The device as claimed in any one of claims 1 to 3, wherein the pressure reducer is formed by a drip chamber.

6. The device as claimed in any one of claims 1 to 3, wherein the pressure reducer is formed by a section of pipe with rungs 30 running transversely in relation to the direction of flow.

7. The device as claimed in any one of claims 1 to 3, wherein the pressure reducer is formed by a meander. 18

8. The device as claimed in at least any one of claims 1 to 7, wherein the sheet pocket is covered with at least one heat insulator, at least on the underside. 5

9 The device as claimed in at least any one of claims 1 to 8, wherein the sheet pocket is covered with at least one transparent heat insulator, at least on the upper side.

10. The device as claimed in claim 8 or 9, wherein the heat 10 insulator is surrounded by a protective film.

11. The device as claimed in claim 10, wherein the protective film is gas-filled. 15

12. The device as claimed in at least any one of claims 1 to 11, wherein the sheet pocket is divided into chambers and/or sections of pipe by separating weld seams.

13. The device as claimed in at least any one of claims 1 to 20 12, wherein the heat transfer medium is radiation-absorbent.

14. The device as claimed in claim 13, wherein the heat transfer medium has a temperature-dependent radiation absorption, the absorption of which decreases with increasing 25 temperature.

15. The device as claimed in at least any one of claims 1 to 14, wherein the sheet pocket and/or the protective film is made UV-resistant and/or gnaw-proof. 30

16. The device as claimed in at least any one of claims 1 to 15, wherein the sheet pocket and/or the protective film has at least one photovoltaic cell of semiconducting material. 19

17. The device as claimed in at least any one of claims 1 to 16, wherein, to influence the through-flow of the heat transfer medium, at least one valve and/or at least one circulating pump is provided in the supply line and/or discharge line. 5

18. The device according to claim 17, wherein the at least one valve and/or at least one circulating pump is in operative connection with at least one sensor. 10

19. The device as claimed in at least one of claims 1 to 18, wherein the device is adhesively fixed on a base.

20. A device for absorbing electromagnetic radiation substantially as herein described with reference to any one of 15 the accompanying drawings of an embodiment of the invention.