DE2643746C2 - Solar collector - Google Patents

Description

15th

20 '

The invention relates to a solar collector according to the preamble of the claim.

The increasing cost of primary energy is forcing cheaper sources to be used for heating purposes. The solar energy represents an 'inexhaustible reservoir.

There are already many attempts to use solar energy more economically. In addition to the direct conversion into electrical current through junction Photocells play the exploitation of the thermal properties of solar energy *: a promising role, because the radiant energy can easily and almost completely be retracted with other flat-plate collectors. This absorbed energy can be immediate used to heat water. The latter also offers convenient transport and Storage medium.

A number of different designs for collectors have already been proposed and implemented. the. From US 30 22 781 a solar collector is known which consists of elastic plastic films, which to folded into a single flat rectangular piece and welded together at the edge. The top slide is connected to the lower film along dividing lines that form flow channels between them for the water serving as the heat transfer medium.

In order to increase the absorption of the sun rays hitting the target collector, at least a plastic film provided with black color or colored by black pigments in the plastic mass.

However, this solar collector has considerable disadvantages of various kinds. First is an off Thermoplastic film welded together to form tube parts after the manufacturing process no longer changeable. Such a solar collector can no longer be subdivided because it is not visible is how the connections for inlet and outlet lines should be made. The cold river, a typical 6 (1 Property of thermoplastics, hardly allows a temperature occurring under solar radiation to last longer Time to. Pressures, such as those that are common in a pumping process, can quickly cause the foils to burst at higher temperatures. Another disadvantage is 6:> ßerdem that the production as z. B. from the drawing of US 30 22 781 is to be assumed, only to one in its size leads to a fixed element forever.

Finally, it is also disadvantageous that this previously known solar collector only has a reduced degree of efficiency can have, since there is no security against heat radiation downwards. Such a heat shield is of considerable importance.

From DE-OS 25 10 321 a nominal collector is known, which can consist of continuously extruded plastic profiles cut to length as required. Natural or synthetic rubber come as materials as well PVC, PMMA and others Plastics in question, which among other things have sufficient weather resistance as well Have resistance to UV light.

The collector can be made as a co-extrudate from two plastics - that is, in one piece - and have several channels for a heat transfer medium. One However, such co-extrusion is extremely difficult, since transparent plastics show a considerably different extrusion behavior than they do with rubber mixtures of the usual type. Also, they are only extrudable and at the same time translucent, elastic plastics to a small extent lightfast.

The object of the invention is therefore to create a solar collector whose absorber is made of a highly flexible material and can be shaped in a variety of ways with regard to the surface geometry, there is a problem-free absorption of thermal dimensional changes can and still has a high stability even in long-term use.

According to the invention, the object is achieved in that the profiles forming the absorber are used as the upper part are integrally connected to a support plate that the channels at the profile ends can be connected to one another by means of connecting hoses and the absorber of surrounded by an insulated housing and covered with a radiation-permeable film.

After vulcanization, the pipe system and support plate are available as a coherent component.

Because of the small amount compared to the rest of the world Thermal conductivity of elastomers, care must be taken that the wall thickness of the flow channel on the the side facing the sun is not oversized. Since this is an almost pressureless circuit, the water pressure should not exceed 2 bar appear.

It is therefore sufficient to limit the wall thickness on this side to about 1 mm.

Flat-plate collectors of this type can be prefabricated in large .1 lengths. The prefabricated systems allow a comparatively simple laying technique and adaptation to the geometric conditions. It Several units can also be combined by connecting them with coupling pieces (e.g. made of plastic), connects with each other. The multiple throughflow in the circuit is achieved by connecting hoses between adjacent channels. In In cases in which a whole multiple of the prefabricated flat-plate collectors does not allow optimal use of space, it is possible to use these collector elements to be shortened to the required dimensions by cutting with suitable devices.

The elastomeric materials used are to remain elastic in the temperature range from -30 to +120 ⁰ C. With regard to the long-term operating conditions, there should also be a high thermo-oxidative and photochemical resistance in connection with water resistance, even with the addition of protective agents against corrosion, freezing, algae and fungal attack. There are therefore elastomers based on rubbers

H add no or in the polymeric main chain

ά contain only a few reactive double bonds. If-

| j probably with this goal also unsaturated AIl-

[I purpose rubber can be used like natural

Il rubber. Polybutadiene, styrene-butadiene mixed poly-

|| merisate. Polyisoprene, homopolymers of chlorine

§J tadicn etc when using non-water extractables

If stabilizers are protected, it is the one to demand

p the long-term resistance because of safer, rubbers

I of the R-Class according to ASTM D-1418 by others to be required set.

H The only exceptions are butyl rubber,

Äi copolymers of isobutylene with a few pro

tS percentages of isoprene and its halogenated derivatives chlorobutyl or bromobutyl or bromobutyl

H tyl rubber. In addition to these two special rubbers

ff from the R series, however, because of the saturated

Pity of their main chain and thus their chemical indifgj especially rubbers, which according to the noun

II class of ASTM-D! 418 to be classified in the »M group« are. These are primarily the copolymers

|| from ethylene and propylene with small amounts of one

i * | dienic monomer (double bond fork in the

f | Side chain), the chlorosulfonated polyethylene, CSSM

|| and possibly the copolymers of ethylene and vinyl

|? | acetate (EVA rubbers) and fluorinated olefins

ft (CFM) and acrylate rubbers (ACH). For special cases

fi can also refer to the mostly expensive rubber

Γ types are thought to conform to ASTM-D 1408, in the

ί Class of CO and U class fall, i.e. heteroatoms

contained in the polymer main chain, such as oxygen ¹ (O) and nitrogen (N). Belong to the former group

for example the polymers of propylene oxide and their copolymers with epichlorohydrin and Seg-Z-, ment copolymers made from terephthalate esters and polybutyl

ienoxiden. The latter group includes mainly 1-borrowed the elastomers made of polyester and possibly polyether

• urethanes. Finally call as the last group of the silicone rubber οι, but which may play a training \ takeover role due to its high price and its lack of resistance to hydrolysis at best for the intended purpose.

The invention is illustrated in connection with three figures.

The A b b. 1 shows a cross section through the collector - gate housing. This consists of the housing 1 with base 2 and the film 3 for covering. Housing and Floors are characterized by good thermal insulation and are preferably made of rigid polyurethane-based foam. The good isolation can be improved by the closed-pore structure. Housing 1

■ and booths 2 can with a layer of aluminum 4

be lined. The radiation-permeable film 3 has the effect that the radiation energy can enter unhindered can. This film is fastened in the housing 1 by a clamping profile 5. The absorber is located in the housing 6. This consists of a profile which has tubular channels 7 on the surface.

A b b. 2 again shows the absorber 6 with the channels 7 from a different point of view.

According to A b b. 3 the channels 7 on the Profilendeii j are connected to one another by means of connecting hoses 8.

For this purpose 3 sheets of drawings

Claims (1)

Claim: Solar collector, consisting of extruded profiles made of rubber or with several parallel channels adjusted to suitable lengths elastic plastic with increased resistance to weathering and UV light, whereby Black-colored profiles through which a heat transfer medium flows form the absorber, characterized in that the profiles forming the absorber (6) are integral with it as an upper part a support plate are connected so that the channels (7) at the profile ends by means of connecting hoses (8) can be connected to one another and the absorber (6) is surrounded by an insulated housing (1) and with a radiation-permeable film (3) is covered. 10 '