GB2436360A

GB2436360A - Solar energy collector comprising a fluid black body heat absorber that can set, cure or harden to a solid

Info

Publication number: GB2436360A
Application number: GB0605840A
Authority: GB
Inventors: Martyn Johnson-Townley
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-03-23
Filing date: 2006-03-23
Publication date: 2007-09-26
Also published as: GB0605840D0

Abstract

A black body device 2 that is a component of a solar energy collector absorbs heat energy from sunlight; the black body device is a fluid means that can set or harden or cure over time being selected by virtue of its black body characteristics and thermal conductivity, or the black body device can be a carrier fluid means that can set or harden or cure over time being intimately mixed with one or several types of filler means that are selected by virtue of their black body characteristics and thermal conductivity. Heat energy is transferred from the black body device to a flow of water through a system of manifolds or pipe work 3 that are in intimate contact with the black body device. The black body device is illuminated by sunlight through the glazing 5 of the solar energy collector. The black body device can be decanted or poured or deployed by a pressurised delivery system onto an insulating substrate 4 or support means 6. The carrier fluid means may comprise a polymer, a colloid, a gel, an epoxy, a resin or an adhesive. The filler means may comprise particles of talc, magnetite, chromite sand, barite, copper powder or filings, tungsten carbide, silicon carbide, graphite impregnated silicon carbide or glass fibre.

Description

A black body device This invention relates to technology to facilitate

the easier fabrication of solar energy driven water-heating units. Much prior art refers to devices that use solar energy to heat water, thereby achieving useful work from the energy in sunlight. To present, the take up of such devices has not been impressive, despite the obvious environmental and economic benefits.

The main issue with prior art is one of expense. The present invention addresses a technology that leads to easier manufacture of these devices thereby improving the economic case for more widespread application.

The present invention proposes a black body device that is a component of a solar energy collector said black body device absorbs heat energy from sunlight said black body device is a fluid means that can set or harden or cure over time said fluid means being selected by virtue of its back body characteristics and by virtue of its thermal conductivity or said black body device can be a carrier fluid means that can set or harden over time said carrier fluid means being intimately mixed with one or several types of filler means said filler means being selected by virtue of their back body characteristics and by virtue of their thermal conductivity heat energy is transferred from the black body device to a flow of water through a system of manifolds that are in intimate contact with said black body device said black body device is illuminated by sunlight though the glazing of the solar energy collection device.

Many devices described in prior art use a fluid as a heat exchange medium, so called "indirect systems". This heat exchange fluid is conveyed to a solar collector array that is optimised to capture heat from the sun and then permit the heat energy to be transferred to the fluid. The heat contained in the fluid is then available to do useflul work, for instance, by transferring its heat energy to water. The water is then made available as part of a hot water supply system.

Many devices described in prior art are "direct systems". Water is conveyed directly to a solar collector array that is optimised to capture heat from the sun and then permit the heat energy to be transferred to the water. The water is then made available as part of a hot water supply system.

Both direct and indirect systems described in prior art use specific configurations of glass or metal fabrication consisting of networks of tubes to carly heat away from a black body within the solar collector array. The present invention can manifest itself as a direct or an indirect system.

The present invention proposes a black body device for use in such systems. The present invention implies several cost effective methods of constructing solar energy collectors. Said black body device also lends itself to a plurality of mass production methodologies.

Many collectors constructed from prior art consist of a manifold of pipe work affixed to a heat conducting flat plate. The flat plate is painted black or has a specialised black coating in order to make it a good absorber of the sun's radiation. The manifold can be a single fluid circuit or several fluid circuits in parallel. The fixing of the manifold to the flat plate is by brazing or welding. The flat plate is insulated to prevent heat loss on its lower face. This lower face is face down against a roof or other structure. The surface of the flat plate facing the sun is usually glazed thus providing air gap insulation between the manifold / plate fabrication and the glazing. The glazing assists in heat capture by the greenhouse effect.

The flat plate is usually made of expensive copper or aluminium. The flat plate is usually the heaviest component of a collector constructed from prior art.

The black body device is a carrier fluid means mixed with a particle filling means.

In some manifestations of the present invention there may be only one type of particle filling means in the black body device. In other manifestations of the present invention the particle filling means can be a composite of several different particle tilling means.

For example metals or metal oxides or ceramics or minerals or a mixture of several of these can be added to a carrier fluid means in order to create a black body device and vary the thermal and black body properties of the carrier fluid means.

The present invention proposes replacing the flat plate with the black body device. The carrier fluid means can be a polymer or colloid or solution or fluid or adhesive or epoxy or resin or gel. The carrier fluid means can be any fluid that cures over time to become solid.

The particle tilling means or combination of several particle filling means is chosen or engineered to have desirable black body characteristics and thermal characteristics. Desirable black body characteristics include high absorbtion of solar energy be it selectively by wavelength or non selectively. Desirable thermal characteristics include high thermal conductivity. Another desirable characteristic is the thermal interconnectivity of the particle filling means in the cured black body device. That is to say, the degree to which particles of the filler are thermally connected once the black body device has cured.

Candidates for particle filling means include the following: talc, magnetite, chromite sand, barite, copper powder or filings, tungsten carbide, silicon carbide, graphite impregnated silicon carbide and glass fibre.

The material of the black body device is exposed to sunlight that passes through the glazing thereby absorbing energy from sunlight.

A typical production process would begin with preparing a flat insulating layer means -such as a polycarbonate sheet that incorporates air gap insulation. The manifold or pipe work means is placed accurately on the flat insulating layer means, possibly with some temporary fixing. A dam is provided around the periphery of the flat insulating layer means. This dam can be the final insulating walls of the finished solar collector. The black body device is then poured onto the flat insulating layer means to a depth sufficient to support and fix in place the manifold or pipe work means. The depth of the black body device must be sufficient to make good thermal contact with the pipe work of the manifold or pipe work means. The viscosity of the carrier fluid means is engineered such that the black body device fully encloses the pipe work before setting solid. In this fashion heat transfer from the black body device to the pipe and thus to the fluid in the pipe is more fully promoted. In any case, the meniscus of the carrier fluid means component of the black body device will assist the process of embedding the pipes of the manifold or pipe work means more fully in the black body device thus making full use of the potential to transfer heat from the black body device to the pipe work means and thus to the fluid in the pipe work means.

This "pouring" process can replace a fabrication intensive welding of the manifold to the flat plate in conventional construction and prior art. In this fashion the present invention has

replaced the flat plate in prior art.

The black body device will take up any tolerance in the flatness of the insulating layer relative to the flatness of the manifold or pipe work means.

Once solidified or cured the black body device serves three main functions: I) Absorbing heat energy from sunlight.

2) Conducting said heat energy to the manifold or pipe work.

3) Fixing the manifold or pipe work to the substrate.

In another manifestation of the present invention the carrier fluid itself can be engineered to have desirable black body and thermal transport characteristics -in this case there is no need for a filler means.

In a further manifestation of the present invention the carrier fluid means remains in a liquid state and does not cure or harden over time. The carrier fluid means must be contained in a fluid proof container means that has a transparent surface facing the sun. The manifold or pipe work means enters and leaves the container means though fluid proof glands. In this manifestation there can be a filler in colloidal suspension. In another manifestation the carrier fluid is a gel that can be filled or unfilled.

The water or heat exchange fluid to be heated flows through the manifold or pipe work means. Heat flow takes place from the black body device through the walls of the tube that forms the manifold or pipe work means and then to the water or fluid. The completed solar collector will also be provided with sensors to detect water or fluid temperature, and devices to guard against over heating and frost damage, and devices to control water or heat exchange

fluid flow as is well described in prior art.

In a further embodiment of the present invention it may be cost effective to deposit a coating means on top of the layer of black body device. Said coating means is one of the coatings designed to improve the black body characteristics of a given surface. This refinement will increase the efficiency of the black body device.

The invention will now be described by way of different implementations and with reference to the accompanying drawing in which: -Figure 1 shows a cross section of the solar collector according to the present invention.

The pipes of the manifold or pipe work means 3 of the solar collector are shown in cross section. Heat exchange fluid flows down these pipes. The number of pipes and the vertical scaling are purely conventional. The viscosity and pouring pattern during production of the black body device 2 has been chosen so that after having cured it encloses the pipes of the manifold or pipe work means 3 completely. There is a transparent glazing means 5. There is an insulation means 4. There is substrate or support means 6 that may or may not be flilly integral with the insulation means. The substrate means 6 can be omitted if the insulation means is sufficiently strong and sufficiently impermeable to the black body device in its liquid phase. The black body device 2 adheres to the insulationl support means 6 and supports the manifold or pipe work means 3.

Claims

Claims 1. A black body device that isa component of a solar energy

collector said black body device absorbs heat energy from sunlight said black body device is a fluid means that can set or harden or cure over time said fluid means being selected by virtue of its back body characteristics and by virtue of its thermal conductivity or said black body device can be a carrier fluid means that can set or harden over time said carrier fluid means being intimately mixed with one or several types of filler means said filler means being selected by virtue of their back body characteristics and by virtue of their thermal conductivity heat energy is transferred from the black body device to a flow of water through a system of manifolds that are in intimate contact with said black body device said black body device is illuminated by sunlight though the glazing of the solar energy collection device.

2. A black body device according to claim I that is deployed in a solar energy collector device such that said black body device is exposed to sunlight.

3. A black body device according to claim 2 that has a carrier fluid means.

4. A black body device according to claim 3 in which said carrier fluid means cures over time to become solid.

5. A black body device according to claim 4 in which said carrier fluid means is engineered to exhibit desired black body characteristics.

6. A black body device according to claim 5 in which said carrier fluid means is engineered to exhibit desired thermal transport properties and heat capacity.

7. A black body device according to claim 6 in which said carrier fluid means is a polymer means.

8. A black body device according to claim 6 in which said carrier fluid means is a colloidal means.

9. A black body device according to claim 6 in which said carrier fluid means is a solution means.

10. A black body device according to claim 6 in which said carrier fluid means is a geJ means.

11. A black body device according to claim 6 in which said carrier fluid means is an epoxy means.

12. A black body device according to claim 6 in which said carrier fluid means is a resin means.

13. A black body device according to claim 6 in which said carrier fluid means is an adhesive means.

14. A black body device according to claim 4 that has a carrier fluid means mixed with a particle filling means.

15. A black body device according to claim 14 in which the particle filling means is engineered to exhibit desired black body characteristics.

16. A black body device according to claim 15 in which the particle filling means is engineered to exhibit desired thermal transport properties and heat capacity.

17. A black body device according to claim 16 in which the particle filling means is chosen for its ability to absorb heat selectively by wavelength.

18. A black body device according to claim 16 in which the particle filling means is chosen for its ability to absorb heat non-selectively by wavelength.

19. A black body device according to claim 14 in which the fraction of particle filling means is chosen to achieve the desired degree of thermal interconnectivity in the cured black body device.

20. A black body device according to claim 15 through claim 19 to which two or more particle filling means have been added in order to beneficially vary the thermal and black body properties of the carrier fluid means.

21. A black body device according to claim 2 that absorbs useful heat energy from sunlight.

22. A black body device according to claim 21 such that heat transfer means are provided in order to transport away heat absorbed by said black body device so that said heat can do useful work.

23. A black body device according to claim 22 in which the heat transfer means is a manifold of pipe work means deployed on the surface of the insulation means said manifold of pipe work means are embedded in the black body device.

24. A black body device according to claim 23 in which heat energy is transferred from the black body device to water flowing in the pipe means.

25. A black body device according to claim 2 that is deployed by painting spraying or some such process directly onto the insulation means that ordinarily form the base structure or substrate of a solar collector means.

26. A black body device according to claim 2 and claim 22 that acts when cured or solidified such as to secure the heat transfer means to the insulation means of a solar collector.

27. A black body device that serves as the heat-absorbing medium in a solar energy collection device said black body device is a fluid means that can harden or cure or toughen over time said black body device is decanted or poured or deployed by pressurised delivery system onto the insulating substrate means or support means that ordinarily forms part of a solar energy collection device said fluid means has itself suitable black body characteristics and coefficient of thermal conductivity for a solar collector or said fluid has a filler means that has suitable black body characteristics and coefficient of thermal conductivity for a solar collector heat energy is transferred from the black body device to a flow of water inside a manifold or pipe work that is in intimate contact with said black body device.

28. A black body device according to claim 27 that is deployed in a solar energy collector device such that said black body device is exposed to sunlight.

29. A black body device according to claim 28 that has a carrier fluid means.

30. A black body device according to claim 29 in which said carrier fluid means cures over time to become solid.

31. A black body device according to claim 30 in which said carrier fluid means is engineered to exhibit desired black body characteristics.

32. A black body device according to claim 31 in which said carrier fluid means is engineered to exhibit desired thermal transport properties and heat capacity.

33. A black body device according to claim 32 in which said carrier fluid means is a polymer means.

34. A black body device according to claim 32 in which said carrier fluid means is a colloidal means.

35. A black body device according to claim 32 in which said carrier fluid means is a solution means.

36. A black body device according to claim 32 in which said carrier fluid means is a gel means.

37. A black body device according to claim 32 in which said carrier fluid means is an epoxy means.

38. A black body device according to claim 32 in which said carrier fluid means is a resin means.

39. A black body device according to claim 32 in which said carrier fluid means is an adhesive means.

40. A black body device according to claim 30 that has a carrier fluid means mixed with a particle filling means.

41. A black body device according to claim 40 in which the particle filling means is engineered to exhibit desired black body characteristics.

42. A black body device according to claim 41 in which the particle filling means is engineered to exhibit desired thermal transport properties and heat capacity.

43. A black body device according to claim 42 in which the particle filling means is chosen for its ability to absorb heat selectively by wavelength.

44. A black body device according to claim 42 in which the particle filling means is chosen for its ability to absorb heat non-selectively by wavelength.

45. A black body device according to claim 40 in which the fraction of particle filling means is chosen to achieve the desired degree of thermal interconnectivity in the cured black body device.

46. A black body device according to claim 41 through claim 45 to which two or more particle filling means have been added in order to beneficially vary the thermal and black body properties of the carrier fluid means.

47. A black body device according to claim 28 that absorbs useful heat energy from sunlight.

48. A black body device according to claim 47 such that heat transfer means are provided in order to transport away heat absorbed by said black body device so that said heat can do useful work.

49. A black body device according to claim 48 in which the heat transfer means is a manifold of pipe work means deployed on the surface of the insulation means said manifold of pipe work means are embedded in the black body device.

50. A black body device according to claim 49 in which heat energy is transferred from the black body device to water flowing in the pipe means.

SI. A black body device according to claim 28 that is deployed by painting spraying or some such process directly onto the insulation means that ordinarily form the base structure or substrate of a solar collector means.

52. A black body device according to claim 28 and claim 48 that acts when cured or solidified such as to secure the heat transfer means to the insulation means of a solar collector.

53. A black body device substantially as herein described above and illustrated in the accompanying drawing.