DE10239371B3 - Insulation for a solar energy collector under a glass cover has a hard foam core with a metal foil lamination to withstand high temperatures without gassing - Google Patents

Abstract

The insulation (1) for a solar energy collector with a covering glass plate (10) has a core (11) of a hard polyisocyanate foam with an aluminum foil lamination (12) on the side towards the glass cover. The insulation (1) for a solar energy collector with a covering glass plate (10) has a core (11) of a hard polyisocyanate foam with an aluminum foil lamination (12) on the side towards the glass cover. The core has a durable thermal resistance of 150-220 degrees C and a thermal conductivity index at most 0.025 W/K.m. The side of the insulation towards the covering glass is covered by a layer (13) of a non-gassing mineral material, using glass or rock wool under a cladding of aluminum foil (14).

Description

The invention relates to a solar panel specified in the preamble of claim 1.

Such a solar collector is from, for example DE 100 59 453 A1 known.

The qualitative now achieved Improvements in the absorber and the glass covers can help Collector standstill, at which no heat dissipation takes place, to temperatures from above Lead 200 ° C. Collector shutdowns occur especially in systems that support heating and consequently for operation in summer, when there is no heat for heating is retrieved, oversized are.

The high temperatures that occur here to lead that the overheated insulation materials outgas. The gases beat on the inside of the Collector glass cover, causing deterioration of the performance, namely the efficiency of the solar collector.

Currently used as core materials aluminum-laminated polyurethane rigid foam panels used, the permanent temperature resistance is a maximum of 110 ° C.

To overheat the core materials and In order to avoid outgassing, aluminum-laminated rigid polyurethane foam panels are used, in which on the glass cover of the collector Mineral insulation materials are upset. The thickness of these layers of insulation must be relative be great overheating to avoid the core material. For example, the insulation layers must have a thickness of have at least 25 mm to ensure that the maximum temperature of 110 ° C not exceeded in the core becomes. Leading to the insulation element is relatively thick, which is both optical and technical establish integration in building areas, in particular Roof areas, difficult.

Added to this is that with increasing layer thickness the risk of outgassing increases, in particular if the mineral insulation Contain binders or, for this sheep's wool, flax or other natural products can be used.

The use is even more problematic such insulation elements for so-called inner roof collectors, where the collectors are integrated into the roof skin and so that they lie directly on the insulation of the roof. Here boundary layer temperatures can of far more than 150 ° C occur, so that outgassing is unavoidable.

The present invention lies based on the task for to create an insulating element for the application mentioned which on the one hand also with higher ones Temperatures no outgassing occurs and the other one if possible low overall strength of the solar collector.

This task is solved if as suggested by claim 1, high temperature resistant polyisocyanurate foam with a permanent temperature resistance between 150 ° C and 220 ° C and a thermal conductivity below 0.025 W / K.m is used. Even with this insulation element is, as is known per se, the core on the cover glass of the collector facing side with a metal, preferably aluminum foil coated.

Such an insulation element can be dimensioned in this way that a permanent temperature resistance of up to 200 ° C is achieved becomes.

Is the insulation element, as with claim 2 proposed, on the opposite side of the cover slip with a Provided a layer of a non-outgassing, mineral material, can at one possible Collector standstill temperature differences of 30 ° C are permitted.

This insulation layer exists according to claim 3 advantageously made of glass or rock wool and has according to claim 5 with a total strength of insulating element less than 50 mm a layer thickness of less than 25 mm.

According to the proposal according to claim 4 the layer is punctiform or over the entire surface of the insulation element, namely which is the insulation element upwardly covering metal foil, glued gas-tight according to claim 6.

However, it can also be according to claim 7 merely placed on the metal foil and with an upper metal foil be defined and covered, which itself with the insulation element is connected gas-tight. Conveniently, the upper metal foil with the underside of the insulation element connected gastight, preferably glued. Here is the adhesive bond, which tends to outgas, in a cooler area.

To further reduce the coefficient of thermal conductivity the core can be designed as a vacuum element.

For this purpose, according to claim 10 the core made of at least partially open-pore rigid polyisocyanurate foam manufactured and with a gas-tight metal or plastic jacket envelops, so that a vacuum of preferably about 0.5 bar can be generated.

This coat can according to claim 11 from a metal cassette with a wall thickness of 0.6 to 2.0 mm exist.

As far as metal foils are used, they should improve the construction of the insulation melementes be dimensioned according to claim 9 so that they are self-supporting, which is achieved with a film thickness of more than 50 μ.

The object of the invention is below using a schematically shown in the drawing embodiment explained.

The drawing shows the partial section of an insulation element according to the invention 1 that below the coverslip 10 a solar panel is arranged.

This insulation element essentially consists of a core 11 Made of polyisocyanurate foam, which is covered on both sides with aluminum foils 12 and 15 is covered.

On the top of the middle aluminum foil 12 there is a layer 13 made of glass or rock wool, which in turn with an upper aluminum foil 14 covered and thus fixed. This aluminum foil 14 sits in a side section 14a continued with the bottom slide 15 is glued. This ensures that the adhesive layer tends to outgas 16 in a cover slip 10 facing away from the area is provided, which experiences less heating.

1

insulating element

10

cover glass

11

core

12

middle aluminum foil

13

Glass- or rock wool layer

14

upper aluminum foil

14a

side section of the film 14

15

lower aluminum foil

16

adhesive layer

Claims (11)

Insulating element for a solar collector with a glass cover, consisting of a rigid polyurethane foam core that is laminated with a metal foil, characterized in that the core ( 11 ) made of rigid polyisocyanurate foam with a permanent temperature resistance between 150 ° C and 220 ° C and with a coefficient of thermal conductivity below 0.025 W / Km and that the core ( 11 ) on the cover slip ( 10 ) the side facing the collector with a metal, preferably aluminum foil ( 12 ) is coated. Insulating element according to claim 1, characterized by a on the cover glass ( 10 ) opposite side applied layer ( 13 ) made of non-degassing, mineral material. Insulating element according to claim 2, characterized in that the layer ( 13 ) consists of glass or rock wool. Insulating element according to claim 2 or 3, characterized in that the layer ( 13 ) is glued on at points or over the entire surface. Insulating element according to claim 3 or 4, characterized in that the thickness of the glass or rock wool layer ( 13 ) with a total thickness of the insulation element ( 1 ) of less than 50 mm is less than 25 mm. Insulating element according to one of claims 2 to 5, characterized in that the layer ( 13 ) made of mineral material on the cover slip ( 10 ) facing side with a metal foil, preferably an aluminum foil ( 14 ), is covered, preferably gas-tight with the insulation element ( 1 ) is glued. Insulating element according to claim 6, characterized in that the layer ( 13 ) made of mineral material loosely between those on the top of the insulation element ( 1 ) metal foil ( 12 ) is inserted and the upper metal foil with the underside of the insulation element ( 1 ) connected gastight, preferably glued. Insulating element according to one of claims 1 to 7, characterized by a metal, preferably aluminum foil attached to the underside ( 15 ). Insulating element according to one of claims 1 to 8, characterized in that the metal foils ( 12 . 14 . 15 ) are self-supporting, preferably have a thickness of more than 50 u. Insulating element according to one of claims 1 to 9, characterized in that the core ( 11 ) consists of at least partially open-pored rigid polyisocyanurate foam, is covered with a gas-tight metal or plastic jacket and a negative pressure of preferably about 0.5 bar prevails in the interior of the jacket. insulating element according to claim 10, characterized in that the jacket with a metal cassette a wall thickness from 0.6 to 2 mm.