GB1602737A

GB1602737A - Solar energy receiving apparatus

Info

Publication number: GB1602737A
Application number: GB34784/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-08-18
Filing date: 1977-08-18
Publication date: 1981-11-18
Also published as: FR2400677A1; DE2836167A1; BR7805315A; CH634912A5

Abstract

The collector element has a transparent tubular sheath (1) which is sealed by a hood (2) made from a thermally conductive material, in order to form a low-pressure evaporating and condensing system. A wick (3) made from a metallic wire mesh having a radiation-absorbing coating is inserted inside the tubular sheath (1). The system thus formed is partly filled with a heat-transfer medium (4) in such a way that in an evaporating region bounded by the transparent sheath (1) the medium is evaporated by irradiated heat (R) and rises to a condensation region in the hood (2) where it condenses with the release of heat and is guided back to the evaporating region by gravity and/or capillary action of the wick (3). The heat is led off for use from the hood (2) by means of a further heat-transport medium. Such a solar collector element has a high efficiency. <IMAGE>

Description

(54) SOLAR ENERGY RECEIVING APPARATUS (71) I, NIGEL GEOFFREY ALAN COB HAM, a British Subject, of Chilverbridge House, Arlington, Polegate Sussex, and DAVID PETER WALKER, a British Subject, of 121, Milton Road, Eastbourne, Sussex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for receiving solar energy and converting it into useful heat. In particular the invention relates to a solar radiation receiving element intended to form at least part of such apparatus.

Thus in accordance with the invention in its widest aspect a solar radiation receiving element comprises a transparent tubular section which is closed at one end and having at its other end a tubular section or cap of thermally conductive material, there being contained within the transparent tubular section a solar radiation absorptive wick and a vaporisable liquid, the assembly thus formed constituting a sealed low pressure boiling and condensing system by which useful heat is transmitted to the thermally conductive tubular section or cap by vapour condensation whilst utilising capillary action with or without gravity - depending on orientation of the element - for return of condensation to the tubular section.

Normally the wick is a gauze of a high thermal conductivity material such as copper mesh, touching or in close adjacency to the inside surface of the transparent tubular section. This wick may also touch or be in close adjacency to the inside surface of the copper section. This wick may have a selective radiation coating such as black chromium or some other radiative absorptive coating such as matt black paint or enamel.

Further it may be arranged that the high thermal conductivity tubular section material may taper towards its end in order to concentrate thermal output and facilitate connection to a heat receptive member.

A particular and at present preferred embodiment of the invention is hereinafter described, by way of example with reference to the diagrammatic drawings accompanying the Provisional Specification in which: Figure 1 is a plan view of a typical solar radiation receiving element; Figure 2 is a section on line II-II of Figure 1; Figure 3 is an enlarged section on line III-III of Figure 2; Figure 4 is an enlarged section on line IV-IV of Figure 2; Figure 5 is an enlarged section on line V-V of Figure 2; and Figure 6 is a plan view of a solar radiation receiving apparatus comprised of a plurality of elements as aforesaid.

Referring now to Figures 1 to 5, there is shown a solar radiation receiving element in the form of a heat pipe comprising a cylindrical tubular section 1 which is made of glass and closed at its lower end. Attached to the upper end of the tubular section 1 is a cylindrical tubular section or cap 2 made of high thermal conductivity material such as copper. The tubular section 1 is lined internally with a copper gauze 3, radiation absorptive with in the form of and contains at the bottom a liquid 4. The envelope thus formed is evacuated and sealed. The tubular section 1 may be double walled if desired.

The area exposed to solar radiation R is normally the transparent section 1 of the pipe.

When radiation passes through this section it impinges on the gauze 3, and now in the form of thermal energy it causes the liquid in the section 1 to boil and vaporise to the top of the section where, upon touching the cap 2, it condenses and yields up its heat to the cap 2.

The condensate then returns to the section 1 by capillary action with or without the association of gravity. Thus the gauze fulfills two purposes: it provides the capillary action for the return of the condensate and acts as an absorber of solar radiation.

Solar radiation elements as aforesaid will normally be arranged side by side and parallel as shown in Figure 6 and the heat may be removed from the top of the heat pipe caps 2 by a fluid flowing past in contact with the top of the heat pipe, as shown in Figure 6. A currently preferred alternative embodiment of the invention could have an outer transparent tube for a further insulating jacket and/or could use a reflection surface of some kind to redirect solar radiation onto the element.

WHAT WE CLAIM IS:- 1. A solar radiation receiving element comprising a transparent tubular section which is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) SOLAR ENERGY RECEIVING APPARATUS (71) I, NIGEL GEOFFREY ALAN COB HAM, a British Subject, of Chilverbridge House, Arlington, Polegate Sussex, and DAVID PETER WALKER, a British Subject, of 121, Milton Road, Eastbourne, Sussex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for receiving solar energy and converting it into useful heat. In particular the invention relates to a solar radiation receiving element intended to form at least part of such apparatus. Thus in accordance with the invention in its widest aspect a solar radiation receiving element comprises a transparent tubular section which is closed at one end and having at its other end a tubular section or cap of thermally conductive material, there being contained within the transparent tubular section a solar radiation absorptive wick and a vaporisable liquid, the assembly thus formed constituting a sealed low pressure boiling and condensing system by which useful heat is transmitted to the thermally conductive tubular section or cap by vapour condensation whilst utilising capillary action with or without gravity - depending on orientation of the element - for return of condensation to the tubular section. Normally the wick is a gauze of a high thermal conductivity material such as copper mesh, touching or in close adjacency to the inside surface of the transparent tubular section. This wick may also touch or be in close adjacency to the inside surface of the copper section. This wick may have a selective radiation coating such as black chromium or some other radiative absorptive coating such as matt black paint or enamel. Further it may be arranged that the high thermal conductivity tubular section material may taper towards its end in order to concentrate thermal output and facilitate connection to a heat receptive member. A particular and at present preferred embodiment of the invention is hereinafter described, by way of example with reference to the diagrammatic drawings accompanying the Provisional Specification in which: Figure 1 is a plan view of a typical solar radiation receiving element; Figure 2 is a section on line II-II of Figure 1; Figure 3 is an enlarged section on line III-III of Figure 2; Figure 4 is an enlarged section on line IV-IV of Figure 2; Figure 5 is an enlarged section on line V-V of Figure 2; and Figure 6 is a plan view of a solar radiation receiving apparatus comprised of a plurality of elements as aforesaid. Referring now to Figures 1 to 5, there is shown a solar radiation receiving element in the form of a heat pipe comprising a cylindrical tubular section 1 which is made of glass and closed at its lower end. Attached to the upper end of the tubular section 1 is a cylindrical tubular section or cap 2 made of high thermal conductivity material such as copper. The tubular section 1 is lined internally with a copper gauze 3, radiation absorptive with in the form of and contains at the bottom a liquid 4. The envelope thus formed is evacuated and sealed. The tubular section 1 may be double walled if desired. The area exposed to solar radiation R is normally the transparent section 1 of the pipe. When radiation passes through this section it impinges on the gauze 3, and now in the form of thermal energy it causes the liquid in the section 1 to boil and vaporise to the top of the section where, upon touching the cap 2, it condenses and yields up its heat to the cap 2. The condensate then returns to the section 1 by capillary action with or without the association of gravity. Thus the gauze fulfills two purposes: it provides the capillary action for the return of the condensate and acts as an absorber of solar radiation. Solar radiation elements as aforesaid will normally be arranged side by side and parallel as shown in Figure 6 and the heat may be removed from the top of the heat pipe caps 2 by a fluid flowing past in contact with the top of the heat pipe, as shown in Figure 6. A currently preferred alternative embodiment of the invention could have an outer transparent tube for a further insulating jacket and/or could use a reflection surface of some kind to redirect solar radiation onto the element. WHAT WE CLAIM IS:-

1. A solar radiation receiving element comprising a transparent tubular section which is closed at one end and having at its other end a tubular section or cap of thermally conductive material, there being contained within the transport tubular section a solar radiation absorptive wick and a vaporisable liquid, the assembly thus formed consituting a sealed low pressure boiling and condensing system by which useful heat is transmitted to the thermally conductive tubular section or cap by vapour condensation whilst utilizing capillary action with or without gravity - depending on orientation of the element - for return of condensate to the tubular section.

2. A solar radiation receiving element according to Claim 1 wherein the wick is a gauze of a high thermal conductivity metal having a radiation absorptive coating.

3. A solar radiation receiving element according to Claim 2 wherein the coating is a selective radiation coating.

4. A solar radiation receiving element according to any of Claims 1 to 3 wherein the tubular section tapers towards its closed end.

5. A solar radiation receiving element according to any of Claims 1 to 4 wherein the transparent tubular envelope is double walled.

6. A solar energy receiving apparatus comprising a plurality of elements as claimed in any of the preceding claims disposed side by side and coupled in series by a flow tube which permits flow of fluid successively past the high thermal conductivity tubular sections.

7. A solar radiation receiving element substantially as hereinbefore described with reference to and as shown in, any of Figures 1 to 5 of the drawings accompanying the Provisional Specification.

8. A solar energy receiving apparatus substantially as hereinbefore described with reference to, and as shown in, Figure 6 of the drawings accompanying the Provisional Specification.