GB1591209A

GB1591209A - Solar heat collector

Info

Publication number: GB1591209A
Application number: GB7543/78A
Authority: GB
Original assignee: Oerlikon Contraves AG
Current assignee: Rheinmetall Air Defence AG
Priority date: 1977-03-02
Filing date: 1978-02-24
Publication date: 1981-06-17
Also published as: CH600267A5; AU513275B2; IT1092817B; IN148442B; IL54083A0; ES467252A1; SE435962B; SU760902A3; FR2382653A1; DE2807804B2; SE7802229L; NL7801731A; BR7801246A; AT365330B; ATA113878A; BE864172A; FR2382653B1; MX147325A; JPS53109238A; DK84778A

Description

(54) A SOLAR HEAT COLLECTOR (71) We, CONTRAVES AG., a Swiss company, of Schaffhauserstrasse 580, 8052 Zurich, Switzerland, 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: The present invention relates to solar heat collectors.

According to one aspect of the invention there is provided a solar heat collector comprising: a liquid inflow conduit and a liquid outflow conduit which are arranged spaced apart from one another, a chamber comprising a front wall made of material which allows solar radiation to pass through it, a rear wall opposite said front wall, and side walls which are made of heat insulating material and which form a framework for supporting the front and rear walls, said inflow conduit and said outflow conduit being embedded within two respective ones of said side walls so as to reinforce them, and so that the embedded sections of said conduits constitute respective liquid manifold chambers within the said two side walls, a plurality of spaced apart interconnection conduits interconnecting the manifold chambers of said inflow and outflow conduits such that the interconnection conduits are within said chamber and such that, in use of the solar heat collector, liquid entering the inflow conduit can pass through the interconnection conduits to the outflow conduit, and means, including solar radiation collection means, for converting solar radiation which enters said chamber via said front wall thereof and impinges upon said collection means into heat energy to heat said liquid as it passes through the interconnection conduits.

Advantageously, said rear wall of said chamber comprises heat insulating material.

Conveniently, the means for converting solar radiation to heat energy comprises means for focussing solar radiation which enters said chamber via said front wall thereof onto the interconnection conduits.

In a preferred arrangement the focussing means comprises, for each said interconnection conduit, a respective associated parabolo-cylindrical reflecting member arranged so that its focal axis coincides with the axis of the associated interconnection conduit, each reflecting member being able to be turned by drive means about its focal axis so as to ensure, for varying angles of incidence of solar radiation onto the collector, focussing of solar radiation received by the member onto the associated interconnection conduit.

Part of the inside surface of the chamber may be blackened.

At least part of said rear wall of the chamber may comprise material which transmits light.

According to another aspect of the invention, there is provided a solar heat collector as described above when installed in its position of use, said position of use being such that said inflow conduit, which is preferably horizontal, is below the outflow conduit so that liquid can flow from the inflow conduit via the interconnection conduits to the outflow conduit by convection caused by heating of the liquid when it is in the interconnection conduits.

By way of example, the aforementioned heat insulating material may be plastics material, foamed plastics material, or other foam material.

In the embodiment of the invention to be described with reference to the drawings the side walls of the collector are made of light-weight constructional material, for example plastic material, foamed plastics material or other foam material. Such materials may not be very strong and rigid inherently and so reinforcement of the walls is preferably provided. By embedding the main liquid inflow and outflow conduits in two of the walls, the cost of providing the necessary strength and rigidity can be reduced. In the embodiment, it will be noticed that the liquid flow conduits and the chamber walls are not all designed and assembled independently of one another.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of part of a solar heat collector according to the invention, Figure 2 is a sectional view of aprt of a practical embodiment of the Figure 1 heat collector, and Figure 3 is another sectional view corresponding to Figure 2.

The heat collector of Figure 1 comprises a horizontal main water inflow conduit 11 and, parallel thereto, a main water outflow conduit 12 for heated water. The heat collector further comprises a totally enclosed chamber having front, rear and side walls none of which are shown in Figure 1 but will be described with reference to Figures 2 and 3. In use of the heat collector, the conduit 11 is positioned at a lower level than the conduit 12. Disposed transversely of the two main conduits and spaced apart from one another in a plane are radiation-absorbing conduits or tubes 13. The axis of each tube 13 coincides with the focusing axis of an associated parabolo-cylindrical mirror 14 which is turned by drive means (not shown in Figure 1) to follow the position of the sun so that, when the sun shines, the sunlight incident on the mirror surface is focussed onto the associated tube 13.The water in the tubes 12 therefore heats up and rises by convection into the main outflow conduit 12.

Figure 2 is a sectional view of part of a practical embodiment of the heat collector looking in the direction along the axis of the conduit 12. Thus there can be seen here one of the tubes 13, the mirror 14 associated with that tube 13, and, in cross-section, the main outflow conduit 12. In contrast to Figure 1, each tube 13 is positioned slightly above the conduit 12 and its end bends into the conduit 12. The heat collector comprises a flat rectangular totally enclosed chamber formed by a front wall 21, a rear wall 22, two longitudinal side walls 23 (only one of which can be seen) and two transverse side walls 24 (of which, again, only one can be seen). The conduits and tubes are arranged so that the tubes 13 and the mirrors 14 lie in the interior 2 of the chamber.The front wall 21 faces the sun in use and is in the form of a glass window 21 which, for improved insulation, can be a double-glazed window. The rear wall 22 consists of a heat-insulating hard foam panel or the like whose inside has been blackened.

The two longitudinal walls 23 and the two transverse walls 24 which are made e.g. of a heat-insulating hard foam material, form a self-supporting frame construction which forms the bearing structure for the front and rear walls 21 and 22. The conduits 11 and 12 extend in the same direction as the longitudinal walls 23 and are, in fact, embedded within these longitudinal walls 23 so as to reinforce them and make them more rigid. The embedded sections of the conduits 11, 12 within the walls 23 constitute respective liquid manifold chambers where the tubes 13 are connected with the conduits 12.

A sprocket wheel 31 having a hub 32 is rotatably mounted on each tube 13 by way of a hub bearing. The hub 32 of each sprocket wheel 31 is secured to an end wall 140 of the associated mirror 14, for example by a threaded portion of the hub extending through a hole in the end wall 140 and a nut 33 being screwed onto the threaded portion as illustrated. A single sprocket chain engages the teeth of each sprocket wheel 31 and also a driving wheel (not shown) which can be rotated by a drive motor (not shown) so that, driven by the common drive motor, the mirrors 14 can be turned in unison to follow the changing position of the sun.

Figure 3 is a sectional view looking in the direction of the axis of the tube 13 which can be seen in Figure 2. Thus there can be seen here the said tube 13 in cross-section and the associated mirror 14 also in crosssection. In elevation, there can be seen the end wall 140 of the mirror, the sprocket 31 with its nut 32 and the common sprocket drive chain 310. The drive chain 310 is enclosed in a channel shaped member which can also be seen in Figure 2. Figure 3 also shows how during the day the mirror 14 is pivoted from its morning position M through its midday position (shown in solid lines) into its evening position A and how the mirror 14 focuses the sunlight S on the associated tube 13. As mentioned ealier the rear wall 22 is blackened. Part or all of the interior surface of the side walls could also be blackened. The function of this blackening is to cause any solar radiation which enters the chamber but is not reflected by the mirrors 14 onto the tubes 13 and any scattered radiation to be absorbed and hence to produce heat which helps to raise the temperature inside the chamber and hence to improve the efficiency of the collector.

As an alternative, however, the rear wall 22 could be made, at least partly, of a transparent material so as to transmit scattered light in the daytime to an area, room or space below or behind the collector. Special conditions can be catered for by choosing varying extents of the blackening of the inside walls of the chamber and the proportion of stray light allowed to pass. Substan tially any light-transmitting plastics, e.g.

acrylic glass or transparent polyvinyl chloride, can be used as a light-transmitting and heat-insulating material.

The solar heat collector shown can be constructed with overall heights of less than from approximately 25 to 30 cm as handy portable roof elements for buildings; all that is necessary is for the outsides of the windows 21 to be cleaned occasionally.

WHAT WE CLAIM IS: 1. A solar heat collector comprising: a liquid inflow conduit and a liquid outflow conduit which are arranged spaced apart from one another, a chamber comprising a front wall made of material which allows solar radiation to pass through it, a rear wall opposite said front wall, and side walls which are made of heat insulating material and which form a framework for supporting the front and rear walls, said inflow conduit and said outflow conduit being embedded within two respective ones of said side walls so as to reinforce them, and so that the embedded sections of said conduits constitute respective liquid manifold chambers within the said two side walls, a plurality of spaced apart interconnection conduits interconnecting the manifold chambers of said inflow and outflow conduits such that the interconnection conduits are within said chamber and such that, in use of the solar heat collector, liquid entering the inflow conduits can pass through the interconnection conduits to the outflow conduit, and means, including solar radiation collection means, for converting solar radiation which enters said chamber via said front wall thereof and impinges upon said collection means into heat energy to heat said liquid as it passes through the interconnection conduits.

2. A solar heat collector according to claim 1, wherein said rear wall of said chamber comprises heat insulating material.

3. A solar heat collector according to claim 1 or 2, wherein said inflow and outflow conduits are substantially parallel to one another and the side walls in which they are embedded are opposite one another.

4. A solar heat collector according to claim 1, 2 or 3, wherein said heat insulating material comprises plastics material, foamed plastics material, or other foamed material.

5. A solar heat collector according to any preceding claim, wherein the means for converting solar radiation to heat energy comprises means for focussing solar radiation which enters said chamber via said front wall thereof onto the interconnection conduits.

6. A solar heat collector according to claim 5, wherein said focussing means comprises, for each said interconnection conduit, a respective associated parabolocylindrical reflecting member arranged so that its focal axis coincides with the axis of the associated interconnection conduit, each reflecting member being able to be turned by drive means about its focal axis so as to ensure, for varying angles of incidence of solar radiation onto the collector, focussing of solar radiation received by the member onto the associated interconnection conduit.

7. A solar heat collector according to any preceding claim, wherein part of the inside surface of the chamber is blackened.

8. A solar heat collector according to any preceding claim, wherein at least part of said rear wall of the chamber comprises material which transmits light.

9. A solar heat collector substantially as hereinbefore described with reference to the accompanying drawings.

10. A solar heat collector according to any preceding claim when installed in its position of use, said position of use being such that said inflow conduit is below the outflow conduit so that liquid can flow from the inflow conduit via the interconnection conduits to the outflow conduit by convection caused by heating the liquid when it is in the interconnection conduits.

11. A solar heat collector installed in its position of use as claimed in claim 10, the said inflow conduit being substantially horizontal.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tially any light-transmitting plastics, e.g. acrylic glass or transparent polyvinyl chloride, can be used as a light-transmitting and heat-insulating material. The solar heat collector shown can be constructed with overall heights of less than from approximately 25 to 30 cm as handy portable roof elements for buildings; all that is necessary is for the outsides of the windows 21 to be cleaned occasionally. WHAT WE CLAIM IS:

1. A solar heat collector comprising: a liquid inflow conduit and a liquid outflow conduit which are arranged spaced apart from one another, a chamber comprising a front wall made of material which allows solar radiation to pass through it, a rear wall opposite said front wall, and side walls which are made of heat insulating material and which form a framework for supporting the front and rear walls, said inflow conduit and said outflow conduit being embedded within two respective ones of said side walls so as to reinforce them, and so that the embedded sections of said conduits constitute respective liquid manifold chambers within the said two side walls, a plurality of spaced apart interconnection conduits interconnecting the manifold chambers of said inflow and outflow conduits such that the interconnection conduits are within said chamber and such that, in use of the solar heat collector, liquid entering the inflow conduits can pass through the interconnection conduits to the outflow conduit, and means, including solar radiation collection means, for converting solar radiation which enters said chamber via said front wall thereof and impinges upon said collection means into heat energy to heat said liquid as it passes through the interconnection conduits.