EP0956483A1

EP0956483A1 - Frame structure of a solar energy collector

Info

Publication number: EP0956483A1
Application number: EP97947755A
Authority: EP
Inventors: Toivo Kärnä; Seppo Peltola; Esko Savolainen
Original assignee: Neste Oyj
Current assignee: Neste Oyj
Priority date: 1996-12-27
Filing date: 1997-12-18
Publication date: 1999-11-17
Also published as: FI101642B1; FI965213A0; NO993166L; FI101642B; WO1998029698A1; AU5400598A; NO993166D0

Abstract

The invention relates to a solar energy collector that comprises at least a cover (11) penetrable by light, an absorber, a system of flow ducts in the absorber, and a frame structure formed of edge profiles (15). The frame structure of the solar energy collector is composed of at least one corner joint, each corner joint comprising at least one insert (17) fitted inside an edge profile (15) and at least one prebent lock pin (18). The inserts (17) are provided with holes (21) for the lock pins (18), said hole (21) including a plane face and said lock pin (18) including a plane face (18a). The joint can be tightened by turning the lock pins (18) such that the plane face (18a) of the lock pins (18) is locked to the plane face of the hole (21) situated in the insert (17).

Description

Frame structure of a solar energy collector

The invention relates to a solar energy collector comprising at least a cover penetrable by light, an absorber, a system of flow ducts in the absorber, and a frame structure formed of edge profiles.

The solar energy collectors known today are, as a rule, manufactured as follows. The collector comprises absorber elements placed inside an insulated box-like structure. In a collector constructed in this way, the cover material of the side absorbing sunlight, i.e. the cover penetrable by light, is either glass or a plastic having good optical properties, such as, for example, PC plastic. The absorbers are manufactured as separate elements. The construction of an absorber element may be, for example, plate-like or narrow, strip-shaped, depending on the mode of manufacture. A pressure-proof liquid space in the interior of absorber elements is either tubular or a space of a wider surface situated between two plates. Various metals, such as, for example, aluminium, stainless steel, copper, etc. may be used as the construction material of absorber elements. Also various plastic and composite materials may come into question. The face receiving thermal radiation of the sun in the absorber elements is treated with a coating that absorbs well, such as, for example, black chromium, black nickel, a special paint or a special tape.

It is known in prior art to form the frame structure of a solar energy collector, for example, out of edge profiles of aluminium, which are attached to one another either by means of a screw joint or by means of a glue joint. The screw joint and the glue joint are labourious mode of joining and, in addition, the glue joint cannot be dismantled. The appearance of the modes of joining known today is also unfavourable. Although the screw joint is a joint that can be dismantled in principle, this kind of frame structure in a solar energy collector is a poor design from the point of view of servicing. The object of the invention is to provide an improvement over the prior-art frame structures of a solar energy collector.

A specific object of the invention is to provide a frame structure of a solar energy collector which can be formed by joining edge profiles to one another in such a way that the servicing, replaceability of components and appearance of the solar energy collector are considerably improved.

The objectives of the invention are achieved by a frame structure of a solar energy collector which is characterized in that the frame structure of the solar energy collector is composed of at least one joint, each joint comprising at least one insert fitted inside an edge profile and at least one prebent lock pin, that an intermediate support or a projection and the insert in the edge profile are provided with a hole for the lock pin, at least one of said holes including a plane face and said lock pin including a plane face, whereby the joint can be tightened by turning the lock pins such that the plane face of the lock pins is locked to the plane face in said hole.

The basic components of the corner joint or corner construction of the solar energy collector in accordance with the invention are edge profiles, preferably e.g. edge profiles of aluminium, metal corner inserts and prebent cotter bolts which are preferably made of spring steel and machined into a plane face at one side at support points. The corner construction may additionally comprise a lead-through piece for a connection tube, or an inlet header, of a system of flow ducts in an absorber.

The corner construction in accordance with the invention functions as an attachment member for the solar energy collector during assembly. The lead-through piece compensates for the thermal movements of unequal size in the absorber and the collector circuit of the solar energy collector and serves as a turning-preventing member that facilitates mounting of a system of flow ducts in the solar energy collector. The frame structure and the corner construction of a solar energy collector in accordance with the invention provide a number of significant advantages in the manufacture and assembly of a solar energy collector. The corner joint which can be readily dismantled facilitates the service of the solar energy collector and makes it possible to replace components of the solar energy collector, for example, a cover glass, an absorber, etc. Owing to the corner insert used in the joint in accordance with the invention, the assembly of the solar energy collector is very quick and simple as compared, for example, with conventional screw joint methods. The play allowed by the lead-through piece reduces the stresses directed to the system of flow tubes and to the absorber while the operating temperature of the solar energy collector varies in the temperature range of even about 200°C. When made out of plastic, in addition to compensating for stresses, the lead-through piece also functions as a heat-insulating element between the frame and the absorber of the solar energy collector. The connection of the tube systems in the solar energy collector to one another on the roof of a building can be accomplished simply by using one key while the lead-through piece simultaneously prevents the turning of the inlet header. The turning-preventing property achieved by means of the structure in accordance with the invention protects the soldered seams of the absorber from twists during assembly or detachment. The corner insert employed in the joint in accordance with the invention serves as an attachment member during assembly, facilitating the installation work often performed in difficult conditions on a pitched roof.

The invention will be described in detail with reference to some preferred embodiments of the invention illustrated in the figures of the accompanying drawings, to which embodiments the invention is, however, not intended to be exclusively confined.

Fig. 1 illustrates a solar energy collector in accordance with the invention viewed from above.

Fig. 2 shows a section along the line II-— II in Fig. 1. Fig. 3 shows a section along the line III— III in Fig. 1.

Fig. 4 illustrates a detail A in Fig. 1 on an enlarged scale.

Fig. 5 is a schematic sectional view of one preferred embodiment of the corner construction of the frame structure in the solar energy collector in accordance with the invention before final tightening of the joint.

Fig. 6 is a schematic sectional view of the embodiment depicted in Fig. 5 after final tightening of the joint.

Fig. 7 shows a section along the line VII— VII in Fig. 6.

Fig. 8 is a schematic sectional view of a second preferred embodiment of the corner construction of the frame structure in the solar energy collector in accordance with the invention before final tightening of the joint.

Fig. 9 is a schematic sectional view of a third preferred embodiment of the corner construction of the frame structure in the solar energy collector in accordance with the invention before final tightening of the joint.

In Figs. 1—8, the solar energy collector in accordance with the invention is denoted generally with the reference numeral 10. The principal components of the solar energy collector 10 are a cover 11 penetrable by light and a plate-like absorber 12. The cover 11 penetrable by light may be a cover part, for example, made of tempered glass. A heat transfer medium flows in a system of flow ducts 13 in the absorber 12. The flow-duct system 13 may be, for example, a system of copper tubes, and as the heat transfer medium it is possible to use water, a mixture of water and glycol, heat transfer fluids, etc.

The heat transfer medium is passed into the system of flow ducts 13 in the solar energy collector 10 by means of a distributing member 14, which may be, for instance, an inlet header. The frame structure of the solar energy collector 10 consists of edge profiles 15. An intermediate support situated in the edge profile 15 is denoted with the reference numeral 15a and slots situated in the edge profile 15 are denoted with the reference numeral 15b. In order to form the frame structure of the solar energy collector 10, edge profiles 15 are cut into a desired angle, preferably, for example, into an angle of substantially 45°, thereby enabling a so-called mitre joint to me made.

The corner construction according to the invention comprises metal corner inserts 17 and prebent cotter bolts 18. The corner construction may additionally comprise a lead-through piece 19 for the inlet header 14. For the lead-through piece 19, a hole suitable for the lead-through piece 19 is machined into the edge profile 15.

The edge profiles 15 are cut into an angle of substantially 45° and, when needed, a hole is machined into the edge profile 15 for the lead-through piece 19. Through- holes 20 are bored in the edge profiles 15 for the cotter pins 18. The holes 20 are bored, for example, in the intermediate support 15a of the edge profile 15. The inserts 17 are provided with holes 21 for the cotter pins 18. The hole 21 in the insert 17 has a plane face 21a and, similarly, the prebent cotter pins 18 have a plane face 18a at one end of the cotter pin 18.

The frame structure of the solar energy collector 10 in accordance with the invention and the corner construction, or the joint, in accordance with the invention are formed in the following way. Corner inserts 17 are placed in the slots 15b inside the edge profiles 15, for example, two inserts for each corner. Next, the lead-through piece 19 (e.g. a heat-resistant injection-moulded plastic part) of the inlet header 14 is mounted in place. Finally, prebent lock pins 18, for example, two, preferably four pins for each corner, are put in place. As the last work phase, the cotter bolts 18 are turned by means of a special key substantially through 180°. The cotter bolts 18 are locked in place while their plane faces 18a lie against the plane faces 21a of the holes 21. Owing to the prebending of the lock pin 18, the joint tightens to a suitable tightness, forming a very strong corner joint which, however, can be easily dismantled.

In the embodiment depicted in Figs. 5—7, as the lead-through piece 19 is used a lead-through piece that comprises a flange part 19a, a lug part 19b and a base part

19c. This kind of lead-through piece 19 compensates for the thermal movements of the absorber 12 and the collector circuit in the solar energy collector 10 and, at the same time, functions as a turning-preventing member that facilitates the assembly of the flow duct system of the solar energy collector. The lead-through piece 19 is mounted in a machined hole situated in the edge profile 15 such that the lead- through piece 19 has play which reduces the stresses acting on the system of flow tubes 13 and on the absorber 12 while the operating temperature of the solar energy collector

10 varies within a relatively large temperature range. When made of plastic, the lead-through piece 19 additionally serves as a heat-insulating element between the frame and the absorber 12 of the solar energy collector 10.

The embodiment depicted in Fig. 8 is otherwise the same as the embodiment depicted in Fig. 5 but in the embodiment of Fig. 8 only one insert 17 is used.

In the embodiment depicted in Fig. 9, the shape of a lead-through piece 19 enables the prevention of rotation. In this embodiment, cotter bolts 18 rest on both sides against a straight face 19d of the lead-through piece 19. In the embodiment illustrated in Fig. 7, the lug part 19b prevents only the lead-through piece 19 from coming out of its hole when the cotter bolts 18 are in place. In the embodiment illustrated in Fig. 9, the cotter bolts 18 are thus placed such that they rest on the straight face 19d of the lead-through piece 19. The cotter bolts 18, then, prevent the turning of the lead-through piece 19 effectively.

The holes 21 may be situated in the insert 17 and/or in the intermediate support 15a and/or in an intermediate projection. Similarly, the holes 20 for the lock pin 18 may be situated in the intermediate support 15a or in the intermediate projection and in the insert 17 of the edge profile 15. Only some preferred embodiments of the invention have been described above, and it is obvious to a person skilled in the art that numerous modifications may be made to them within the inventive idea presented in the accompanying claims.

Claims

1. A solar energy collector (10) comprising at least a cover (11) penetrable by light, an absorber (12), a system of flow ducts (13) in the absorber, and a frame structure formed of edge profiles (15), characterized in that the frame structure of the solar energy collector (10) is composed of at least one joint, each joint comprising at least one insert (17) fitted inside an edge profile (15) and at least one prebent lock pin (18), that an intermediate support (15a) or a projection and the insert (17) in the edge profile (15) are provided with a hole (20,21) for the lock pin (18), at least one of said holes (21) including a plane face (21a) and said lock pin (18) including a plane face (18a), whereby the joint can be tightened by turning the lock pins (18) such that the plane face (18a) of the lock pins (18) is locked to the plane face (21a) in said hole (21).

2. A frame structure of the solar energy collector as claimed in claim 1, characterized in that the edge profiles (15) to be joined to one another are cut into substantially the same angle.

3. A frame structure of the solar energy collector as claimed in claim 1 or 2, characterized in that the edge profile (15) is provided with a lead-through piece (19) for passing a heat transfer medium into a system of flow ducts (13) by means of a distributing member (14).

4. A frame structure of the solar energy collector as claimed in claim 3, character- ized in that the lead-through piece (19) comprises a flange part (19a), a lug part

(19b) and a base part (19c).

5. A frame structure of the solar energy collector as claimed in claim 3 or 4, characterized in that the lead-through piece (19) is made of a heat- insulating material, preferably a plastic material, whereby the lead-through piece (19) functions as a heat- insulating element between the frame and the absorber (12) in the solar energy collector (10).

6. A frame structure of the solar energy collector as claimed in any one of claims 3 to 5, characterized in that the lock pins (18) are arranged to prevent the turning of the lead-through piece (19).

7. A frame structure of the solar energy collector as claimed in claim 6, characterized in that the lead-through piece (19) has straight faces (19d).