SE1351539A1 - Light absorbing unit - Google Patents

Abstract

The present invention relates to a light absorbing unit (I) for heating via a light transmissive layer (70) at least one liquid medium (L) by solar energy comprising a channel configuration (22) within said light transmissive layer (70) in which said liquid medium (L) ) is arranged to flow for said heating, wherein light absorbing means (30) are configured to substantially accommodate said channel configuration (22), said light transmissive layer (70) comprising a semi-transparent solar cell element (76). (Fig. 2)

Description

TECHNICAL FIELD The invention relates to a light-absorbing unit according to the preamble of claim 1.

BACKGROUND Light-absorbing units are available in a myriad of designs in which a liquid medium, for example, water or a gaseous medium, for example, air is heated by light radiation than the sun. An advantage of a water-borne system compared to an air-borne system is, among other things, that it is easier to connect it to an already existing water-borne system, as opposed to interacting between an air-borne and a water-borne system. Liquid is also more energy-efficient than air, whereby higher efficiency is achieved if the interaction between air and water can be avoided.

A variant of a light-absorbing unit is a so-called flat solar collector - a charge-like construction with an outer glass plate that lets through light radiation, whereby a liquid-shaped medium is circulated in a tube system in a substantially closed space under the glass plate, whereby the medium is heated by said light radiation.

Such devices are intended to be stationary placed on house walls / roofs, whereby the heated medium can be used, for example, to heat the air in the building or to produce domestic hot water.

FR2499693A1 discloses a light absorbing unit for heating a liquid medium via a transparent surface layer by solar energy comprising a channel configuration in the form of hoses within said transparent surface layer in which said liquid medium is arranged to flow for said heating, the light absorbing parts of the hose shaped and the hoses enclosing the upper and lower plate forming thermal contact are present. The unit further comprises an inner transparent layer for thermally insulating said duct configuration of said liquid medium against the ambient air. The light-absorbing unit is intended to form an integral part of a roof construction. The light-absorbing unit is arranged to support roof tiles.

OBJECT OF THE INVENTION An object of the present invention is to provide a light-absorbing unit for a liquid-shaped medium which enables flexible and efficient energy exchange.

SUMMARY OF THE INVENTION This and other objects, which will become apparent from the following description, are accomplished by means of a light absorbing unit of the kind initially indicated and further having the features set forth in the characterizing part of the appended independent claims 1. Preferred embodiments of the light absorbing unit are defined patent claims.

According to the invention, the objects are achieved with a light absorbing unit for heating via a light transmissive layer at least one liquid medium by solar energy comprising a channel configuration within said light transmissive layer in which said liquid medium is arranged to flow for said heating means. said channel configuration, said light transmissive layer comprising a semi-transparent solar cell element. This makes it possible, in addition to generating thermal energy by letting solar energy in the form of direct sunlight, to relax through the semi-transparent solar cell element to the light-absorbing means for generating electrical energy where the proportion of thermal energy and electrical energy is determined by the degree of light transmittance of the semi-transparent solar cell element. The greater the transparency, ie. the greater the light transmittance of the semi-transparent solar cell element, the greater the share of thermal energy and the relatively smaller share of electrical energy and vice versa. As a result, two functions are obtained in one and true unit in that both thermal energy and electrical energy are generated so that a hybrid solution is obtained. This makes it possible for a set of such light-absorbing units arranged, integrated according to a variant, in, for example, a roof construction or cradle construction to have different degrees of light transmittance in different units. Furthermore, the degree of light transmittance can be adapted to geographical position by, for example, in warmer climates having a greater degree of generation of electrical energy and in cooler climates having a greater degree of generation of thermal energy. Consequently, the semi-transparent solar cell element enables flexible and efficient energy exchange.

According to an embodiment of the light absorbing unit, said semi-transparent solar cell element comprises a thin film solar cell for generating electrical energy. This enables efficient generation of electricity in a compact design. According to one variant, said thin film solar cell includes cadnium Tellurid, CdTe.

According to an embodiment of the light-absorbing unit, said light-transmissive layers comprise two transparent layers in which the said solar cell elements are arranged. This results in a stable and robust and for good sealing adapted semi-transparent solar cell element which can thereby form the outer layer when used outdoors. According to an embodiment of the light-absorbing unit, at least one of said transparent layers is constituted by a glass material. Glass is a breathable material that is robust and has good light transmittance.

According to an embodiment of the light-absorbing unit, said light-transmissive layers are arranged at a distance from said light-absorbing means for forming an insulating space. This enables the depleted generation of thermal energy in that heat losses can be avoided by the thus formed insulating space / insulating layer.

According to an embodiment of the light-absorbing unit, said light-transmissive layers are arranged to abut against said light-absorbing means in a heat-exchanging configuration. By thus lazing the light-transmissive layer, i.e. the sennitransparent solar cell element, abutting against the light-absorbing agent, thermal contact is created between them leading to heat exchange. This results in a relatively lower generation of thermal energy compared to the variant with the insulating layer created by having the light-transmissive layer at a distance from the light-absorbing means, but a higher generation of electrical energy as the temperature due to the heat exchange will be lower in the solar cell element. Consequently, a cooling effect is obtained for higher efficiency in the semi-transparent solar cell element. Furthermore, a relatively lower light-absorbing unit is obtained, which enables a total height which substantially corresponds to the height of a traditional barlact on a roof, which makes it possible to install such light-absorbing units on an existing roof by replacing the existing barlact with one or more on the roof. light-absorbing devices according to this variant.

According to one embodiment of the light absorbing unit, said light absorbing unit is substantially parallelepipedically configured. A well-designed light-absorbing unit facilitates construction and installation, for example during installation for integration into roof or cradle construction.

According to one embodiment, the light-absorbing unit is intended to form an integral part of a roof, cradle, balcony or balcony construction. By integrating a set of such light-absorbing units, it is possible to have different degrees or the same degree of light transmittance in different units. By thus integrating the light-absorbing unit, an aesthetically attractive construction is obtained in that a construction and shape are obtained which are essentially no different from the building. Because they are perfectly integrated, they are consequently responsible for deflecting and consequently responsible for stealing. Because they are integrated and consequently not exposed, they also do not collect dirt, leaves or the like to the same extent as a unit arranged on a roof or road. By integrally integrating the light-absorbing unit, the service life is required.

According to one embodiment, the light-absorbing unit is intended to form an integral part of one in a roof construction, the roof construction comprising transparent roof tiles. By thus integrating the light-absorbing unit, an aesthetically attractive construction is obtained in that a construction and shape are obtained which are essentially no different from the building. Because they are integrated and consequently not exposed, they also do not collect dirt, leaves or the like to the same extent as a unit arranged on a roof or road. By integrally integrating the light-absorbing unit, the service life is required.

DESCRIPTION OF THE DRAWINGS The present invention will be better understood by reference to the following detailed description of the drawings taken in conjunction with the accompanying drawings, in which like reference numerals appear in like manner throughout the many views, and in which: Fig. 1 schematically illustrates a perspective view of a light absorbing unit. according to an embodiment of the present invention; Fig. 2 schematically illustrates a cross-sectional end view of a part of the light-absorbing unit; Fig. 3 schematically illustrates a cross-sectional end view of a portion of a light absorbing unit according to an embodiment of the present invention; Fig. 4 schematically illustrates a perspective view of light absorbing units according to Fig. 1 integrated in a roof construction; Fig. 5a schematically illustrates a gable view of the light absorbing unit of Fig. 1 integrated in a roof structure; Fig. 5b schematically illustrates a cross-sectional end view of the light absorbing unit integrated in a roof structure; and Fig. 5c schematically illustrates a gable view of a light absorbing unit in Fig. 1 integrated in a roof structure.

DESCRIPTION OF EMBODIMENTS Fig. 1 schematically illustrates a perspective view of a light absorbing unit I according to an embodiment of the present invention, and Fig. 2 is a cross-sectional end view of a portion of the light absorbing unit I.

The light absorbing unit I is intended to heat at least one liquid-shaped medium L by means of solar energy via a light-transmissive layer 70.

The light absorbing unit I comprises a channel configuration 21, 22 within said light transmissive layer 70 in which said liquid medium L is arranged to flow for said heating.

The light absorbing unit I comprises light absorbing means 30 configured to substantially accommodate said channel configuration 21, 22. The light absorbing means 30 is arranged for generating thermal energy 7 by letting solar energy in the form of direct sunlight is passed through the light transmissive layer 70 to the light absorbing means. For heating said liquid medium.

The light absorbing unit I further comprises means, for example a pump device (not shown), arranged to effect said flow of the liquid-shaped medium L.

Said light transmissive layer 70 comprises a semi-transparent solar cell element 76.

Said semi-transparent solar cell element 76 includes a thin film solar cell 76 for generating electrical energy. According to one variant, said thin film solar cell 76 includes cadmium Telluride, CdTe.

The light absorbing unit I is hereby arranged to generate electrical energy by means of said semi-transparent solar cell elements 76 and by light radiation in the form of direct sunlight which is allowed to relax through the semi-transparent solar cell element 76 by means of the light absorbing means heating the liquid generating medium circulating of thermal energy. Consequently, in addition to the generation of thermal energy, it is also possible to generate electrical energy where the proportion of thermal energy and electrical energy is determined by the degree of light transmittance of the semi-transparent solar cell element.

Said light-transmissive layers 70 have two transparent layers 72, 74 between which said solar cell elements 76 are arranged.

Said transparent layer 72, 74 comprises an outer transparent layer 72 intended to be arranged externally of the solar cell element and consequently against incoming sunlight. Said transparent layer 72, 74 comprises an inner transparent layer 74 intended to be arranged inside the solar cell element and consequently accustomed to said light-absorbing means 30. At least one of said transparent layers 72, 74, preferably! The layers 72, 74, consist of a glass material .

Said light-transmissive layer 70 arranged at a distance from said light-absorbing means 30 for forming an insulating space 3 / insulating layer 3. Said light-transmissive layer 70 arranged at a distance from said light-absorbing means 30 so that heat loss through heat bridges is avoided.

Said light-transmissive layer 70 is hereby arranged to thermally insulate said duct configuration 21, 22 of said liquid-shaped medium L against the ambient air.

Said light-transmissive layer 70 is arranged in connection with and at said distance D1 from said channel configuration 21, 22 and consequently light-absorbing means 30 for allowing efficient heating of said liquid-shaped medium L by means of solar energy.

The light-transmissive layer 70 of the light-absorbing unit I arranged at a distance D1 from the light-absorbing means 30 is configured to provide functionality such as thermal insulation / seal to provide a high thermal energy yield in the light-absorbing unit I.

According to this embodiment, the light-transmissive layer 70 is arranged to thermally insulate the channel configuration 21, 22 of the flowing medium L.

According to one embodiment, the light transmissive layer 70 is arranged in such a manner including sealing / insulating thermal and distance D1 from the light absorbing means that thermal energy transfer according to the type described above in the light absorbing unit I per unit time is maximized for a given light transmission of the semi-transparent cell 76. of the light-transmissive layer 70. The said light-absorbing unit I is substantially parallelepipedically configured. The said light-absorbing unit I consequently has a charged configuration.

The light absorbing unit I is elongate and has two parallel and spaced long sides 42, 44, two parallel and spaced short sides 46, 48 connected to the long sides 42, 44 forming a substantially rectangular shape. Furthermore, the light absorbing unit I has a sub-side 45 connecting the long sides 42, 44 and the short sides 46, 48. The thus connected long sides, the short sides and the bottom side thereby form a charging unit 40 arranged to receive and accommodate said channel configuration 21, 22 and said light absorbing means 30.

The light absorbing unit I comprises insulating means 50 with insulating properties. Said insulating means 50 is arranged in said charge-shaped unit 40 of the light-absorbing unit I.

Said insulating means 50 comprises an insulating layer 52.

The insulating layer 52 is formed according to a variant of a rock wool mat. The insulating layer 52 is configured to be disposed on the bottom of the charge-shaped unit.

Said insulating means 50 comprises side insulating elements 54, 56 arranged for insulating the long sides 42, 44 of the light absorbing unit I. Said side insulating elements 54, 56 comprise a first side insulating element 54 arranged in the charge-shaped unit to abut substantially against and run along one long side 42 and a second side insulating elements 56 arranged in the charge-shaped unit to abut substantially against and run along the second long side 44 of the light absorbing unit I. The first and second side insulating elements 54, 56 have a height which substantially corresponds to the height of the first and second long sides 42, 44. insulation means 50 further comprises end insulation means (not shown) arranged for insulating the short sides 46, 48. The light absorbing unit I comprises a bar layer 60 which is included in the second long side 44. The bar layer 60 is described in more detail below with reference to Figs. 4, 5a and 5b and Fig. 2.

The insulating layer 52 is arranged to be housed between the first and second side insulating elements 54, 56.

The light absorbing means 30 together with the channel configuration 21, 22 form an absorber means 35. The absorber means 35 has an elongate shape. The absorber means 35 has a surface which is black, or dark as dark gray, dark blue, dark green or the like for said light absorption.

In this case, said liquid-shaped medium L is intended to flow in said thirsty and second channel portion for heating. The first and second duct portions 21, 22 are formed according to a variant of copper pipes with good heat conduction.

In addition, the light absorbing unit comprises annular sealing portions Ti, 12 arranged to enclose the respective channel portion 21, 22 and substantially abut against the short side 46, 48 in connection with the channel portion 21, 22.

Through said sealing portions Ti, 12 good sealing is obtained in the light-absorbing unit I. Furthermore, substances such as pollen, leaves or the like are prevented from entering and coming into contact with the light-absorbing means 30 so that the absorption is impaired. Furthermore, the risk of fire due to incoming flammable substances such as dry leaves or the like is avoided. Furthermore, better sealing preserves better heat retention and consequently a more energy-efficient light-absorbing unit I. In addition, simple assembly is achieved.

Fig. 3 schematically illustrates a cross-sectional end view of a part of a light absorbing unit II according to an embodiment of the present invention.

The light absorbing unit II according to the embodiment illustrated in Fig. 3 differs from the light absorbing unit I according to the embodiments 11 illustrated in Figs. 1 and 2 mainly by the orientation of the light-transmissive layer 70.

According to the embodiment of the light-absorbing unit II in Fig. 3, said light-transmissive layers 70 are arranged abutting against said light-absorbing means in a heat-exchanging configuration.

The light transmissive layer 70 with the semi-transparent solar cell element 76 is arranged to abut the light absorbing means 30 so that thermal contact is created therebetween for the heat exchanging configuration. This results in a relatively lower generation of thermal energy compared to having the light-transmissive layer 70 at a distance from the light-absorbing means 30. Thanks to the heat exchange, the temperature will be lower in the solar cell element, which means a higher generation of electrical energy.

The height H2 of the light-absorbing unit II then becomes lower than the height H1 of the light-absorbing unit I, see Fig. 2. This enables a total height H2 which essentially corresponds to the height H2 of a traditional bar roof on a roof, which makes it possible to install on an existing roof. such light-absorbing units II by replacing the existing bar layer with one or more light-absorbing units according to this variant at the desired location on the roof.

Fig. 4 illustrates a perspective view and Figs. 5a-b end views of arrays of the light absorbing unit I integrated in a roof structure 100.

The light-absorbing unit I according to this embodiment is intended to heat a liquid-shaped medium L by means of solar energy via a transparent surface layer 10 in the form of a roof covering, where the roof covering comprises transparent roof tiles 10, according to a variant glass tiles. In that said roofing comprises transparent roof tiles 10, an aesthetically pleasing light-absorbing device is made possible where the light-absorbing unit I is integrated in a roof structure 100 and the light-absorbing unit I 12 consequently forms an integral part of the roof structure 100, where the light-absorbing unit includes is easy to replace or redesign.

The transparent surface layer 10, i.e. the roof tiles 10, provide functionality as mechanical protection against fOrennal, e.g. falling tree branches or hail, or condition, e.g. wind forces, etc., as well as insulation.

The light-absorbing device I comprises a space 2 inside said roof covering in which said liquid-shaped medium L is arranged to flow.

The light-transmissive layer 70 is thus arranged between the thermally insulated channel configuration 21, 22 and the surface layer 10 in the space 2. In this case, the transparent surface layer 10 in the form of said roof tiles 10 forms an outer transparent layer and the light-transmissive layer 70 an inner light-transmissive layer for possible of generation of thermal energy and electrical energy.

The underside 45 is intended to be water against and lie on vertical lacquer portions 104, so-called strolact 104, of a roof as shown in Fig. 5a.

Said transparent roof tiles 10 of said transparent surface layer are arranged to be supported by the bar layer 60 of the light-absorbing unit I.

Said bar layer 60 is arranged to form part of said light-absorbing unit I in said roof structure 100, said bar layer 60 being arranged to be applied in said roof construction 100 with said light-absorbing unit I.

As can be seen from Fig. 2, among others, said bar lacquer 60 has a substantially L-shaped cross section transverse to its longitudinal direction. Said bar sheet 60 comprises an upper portion 62 as a support for roof tiles 10. Said upper portion 62 having the bar sheet 60 is arranged to protrude above a top side 70 of said light-absorbing unit I.

Said bar layer 60 further comprises a foot portion 64 of said L-shaped cross section.

Said upper portion 62 is shorter transverse to the longitudinal direction of the bar axis 60 than said foot portion 64. Consequently, said upper portion 62 has an extension S1 transverse to the longitudinal direction of the bar axis 60 which is shorter than the extension S2 of the foot portion 64 transverse to the longitudinal direction of the bar 60.

Said bar sheet 60 has an intermediate 44 portion intended to constitute one long side 44 of the light absorbing unit I.

Said upper portion 62 has a downwardly open substantially U-shaped configuration. Said upper portion 62 comprises a flat top portion 62a arranged to project in the direction from the long side 44 of the light-absorbing unit I.

Said upper portion 62 further comprises a hook portion 62b directed neatly at an angle, according to a variant substantially perpendicular, from said flat top portion 62a, running parallel to and spaced from said intermediate portion 44.

Said foot portion 64 has an raised Open substantially U-shaped configuration. Said foot portion 64 comprises a flat bottom portion 64a arranged to project in the direction Than the long side of the light-absorbing unit I. Said foot portion 64 is according to the embodiment illustrated in Fig. 4 intended to lie against a transverse lacquer portion 104 of the roof structure 100 running. 64 further includes a stop portion 64b directed upwardly at an angle, according to a variant substantially perpendicular, from said flat bottom portion 64a, running parallel to and spaced from said intermediate portion 44. Said stop portion 64b of the foot portion 64 is arranged to constitute a stop for the light absorbing the unit I said that it is not moved. Between the stop portion 64b of bar lacquer 60 of a light absorbing unit I and an adjacent light absorbing unit is a spacer 80 in the form of an element running between 14 adjacent light absorbing units. This avoids overlapping of roof tiles, which optimizes the light input towards the light-transmissive layer. Instead of providing spacers 80 as illustrated in Figures 5a and 5b, the bottom portion 64a of the bar act 60 may be widened so that the stop portion 64b abuts adjacent light absorbing unit and thus forms spacers. Alternatively, as illustrated in Fig. 5c, the light absorbing unit may be widened so that the stop portion 64b abuts adjacent light absorbing unit.

Said L-shaped cross-section of the bar sheet 60 is according to an embodiment 10 arranged to be produced by extrusion.

Said bar lacquer could, according to an alternative variant, constitute a separate unit and be arranged to be fastened at the bottom by means of a fixed or screw joint at one long side of the light-absorbing unit.

From the respective long side 42, 44 a support portion 42a, 44a is arranged to project in the direction from the long side 42, 44 of the light-absorbing unit I towards each other and arranged to run along the respective long side 42, 44. Respective support portions 42a, 44a are arranged to support the light-transmissive layer 70. The light-transmissive layer 70 is wedge-likely arranged to rest on and is supported by said support portions 42a, 44a. The respective support portion 42a, 44a further comprises a hook portion 42b, 44b directed downwardly from the respective support portion 42a, 44a to facilitate retention of said side insulating elements 54, 56.

From the respective long side 42, 44 a bottom fixed portion 42c, 44c is arranged to project in the direction from the long side 42, 44 of the light absorbing unit I towards each other and arranged to run at a height with the underside 45 along the respective long side 42, 44. Respective bottom fixed portion 42c, 44c are arranged to form a fixed portion for the underside 45, where the underside is constituted by a bottom plate 45. The respective bottom fixed portion 42c, 44c has a recess against which the bottom plate is arranged to be fixed by means of fixed elements, according to a variant by means of double-sided adhesive tape.

According to a variant, the respective short side 46, 48 has a corresponding support portion for supporting the light-transmissive layer 70 and a bottom fixing portion for fixing the bottom disc 45 which the long side 42 has. According to a variant, the long side 42 and the short sides 46, 48 form a unit which during manufacture has been a straight long unit which has since been cut so that the short side 46, 48 and the long side 42 are formed by bending the short sides 46, 48 perpendicular to the long side 42 so that the long side and the short sides form a U-shape seen in a plan view.

Fig. 5a shows the light absorbing unit I with a part of a roof structure 100. The roof structure comprises a bottom layer 102 including a roof layer which according to a variant comprises conventional roofing felt.

On the bottom layer 102, conventional vertical lactate portions 104, so-called strolact or strollact portions 104, are arranged at a distance from each other. Vertical roof sections refer to roof sections that run along the roof structure from the eaves to the ridge perpendicular to the horizontal direction.

Fig. 5c schematically illustrates a gable view of a light absorbing unit III in Fig. 1 integrated in a roof construction.

The light-absorbing unit III according to Fig. 5c differs from the light-absorbing unit I for example according to Fig. 5a in that the light-absorbing unit III is slightly wider than the light-absorbing unit I so that the foot portion of the bar layer 60 forms a spacer between two adjacent light-absorbing units III. A slightly larger surface of the light-transmissive layer 70, not shown in Fig. 5c, is obtained for improved energy yield. Figs. 4, 5a and 5b show the light absorbing unit I integrated in a roof construction. The light absorbing unit II illustrated in Fig. 2 can also advantageously form an integral part in a roof construction.

Named light absorbing unit I; II; III is arranged so that said channel portions 21, 22 run substantially parallel to each other and parallel to the horizontal bar layers 60 and at such a distance that the bar layers 60 do not shade the channels 21, 22. This results in more efficient heating of the liquid-shaped medium L.

A light-absorbing unit is connectable at the sieve end portion via the projecting channel portions 21, 22 by connecting channel portions of the one light-absorbing unit I; II; Ill with channel portions of an additional light-absorbing unit in each other's longitudinal extension.

A set of joined light absorbing units integrated in a roof structure has at least one inlet and at least one outlet.

Accordingly, the liquid medium L is arranged to flow between the inlet and the outlet of the configuration of channels 21, 22 for heating the same.

The light absorbing unit I; II; III according to the present invention may be used for heating one or more liquid media for any desired purpose. For example, the light absorbing unit can be used to heat hot water for domestic hot water, hot water in accumulator tanks to run against heating systems such as radiators, liquid air convectors or underfloor heating, and to regenerate energy wells and / or hot pool water.

The light absorbing unit I; II; Ill as above have two parallel and spaced apart channel portions 21, 22 running along the longitudinal extent of the light absorbing unit. The light absorbing unit I could alternatively have one channel portion or more than two channel portions running in the longitudinal direction of the light absorbing unit. Above, an embodiment of a light absorbing means 30 has been described for heating the liquid-like diet. However, the light absorbing means may have any suitable design for heating by solar energy and is not limited to the light absorbing means 30 according to the described embodiments.

The corresponding light-absorbing unit could alternatively form an integral part of a cradle structure, an integral part of a balcony structure or an integral part of a balcony structure.

The light absorbing unit I; II; III according to the present invention may alternatively constitute a non-integrated light-absorbing unit and can consequently be applied, for example, to a roof or a cradle for said generation of thermal and electrical energy.

The light absorbing unit I; II; III according to the embodiments of the present invention has a substantially parallelepipedic shape. However, the light absorbing unit according to the present invention may have which son is a suitable geometric shape for said generation of thermal and electrical energy.

The light absorbing unit I; II; III according to the embodiments of the present invention has a bar lacquer 60. The light absorbing unit according to the present invention can be designed without bar lacquer, which is suitable for integration in a cradle construction or balcony construction and for non-integrated variants.

The above description of the preferred embodiments of the present invention has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the variations described. Obviously, many modifications and variations will occur to those skilled in the art. The embodiments have been selected and described in order to best explain the principles of the invention and its practical applications, thereby enabling one skilled in the art to understand the invention 18 for different embodiments and with the various modifications which are appropriate to the intended use. 19

Claims (9)

PATENT REQUIREMENTS A light absorbing unit (I; II; III) for heating via a light transmissive layer (70) at least one liquid medium (L) by solar energy comprising a channel configuration (21, 22) within said light transmissive layer (70) in which said liquid medium (L) is arranged to flow for said heating, wherein light absorbing means (30) are configured to substantially enclose said channel configuration (21, 22), characterized in that said light transmissive layer (70) comprises a semi-transparent solar cell element (76). The light absorbing unit according to claim 1, wherein said semi-transparent solar cell element (76) comprises a thin film solar cell (76) for generating electrical energy. A light absorbing unit according to claim 1 or 2, wherein said light transmissive layer (70) comprises two transparent layers (72, 74) between which said solar cell element (76) is arranged. A light absorbing unit according to claim 3, wherein at least one of said transparent layers (72, 74) is constituted by a glass material. A light absorbing unit according to any one of claims 1-4, wherein said light transmissive layer (70) is arranged at a distance (D1) from said light absorbing means (30) for forming an insulating space. A light absorbing unit according to any one of claims 1-4, wherein said light transmissive layer (70) is arranged abutting against said light absorbing means (30) in a heat exchanging configuration. A light absorbing unit according to any one of claims 1-6, wherein said light absorbing unit (I; II; III) is substantially parallelepipedically configured. A light-absorbing unit according to any one of claims 1-7, which light-absorbing unit (I; II; III) is intended to form an integral part of a roof (100; 200), cradle, balcony or balcony construction. A light absorbing unit according to any one of claims 1-7, which light absorbing unit (I; II; III) is intended to form an integral part of a roof structure (100; 200), the roof structure comprising transparent roof tiles (10).