DE102008020621A1 - Solar wall element - Google Patents

Abstract

The invention relates to a solar wall element (1) for heat recovery from solar radiation energy (2), in particular for use as part of an outer building envelope comprising a body (3) and / or hollow body of at least partially transparent or at least translucent and / or light-conducting materials , It is envisaged that the materials have heat-insulating properties due to their material properties and / or due to their structural design. The invention further relates to a building with at least one such solar wall element. It is provided that the wall element (1) is fully or partially integrated in a heat-storable building envelope, however, so that at least one side of the body (3) is arranged on the outer surface (8) that it reaches from the sunlight (2) becomes.

Description

The The present invention relates to a solar wall element having the features of the preamble of claim 1. In the present invention It is a new development in the field of construction technology. she finds particular application in buildings made of exposed concrete and buildings storage walls from other materials. The invention, in the following context referred to as solar wall element, wall heating element or shorter than solar stone, should be in exterior walls or roofs one Energy saving through the use of solar energy to heat the Allow component. For this purpose, the transparent solar stone is installed in the wall or shed that heat contained in the solar radiation in a heat storing part of the component to be initiated.

in the Area of transparent thermal insulation is Researched for many years and there are now some products on the market. However, this technology is not widely used. Reasons are below other high costs, as well as technical difficulties during installation and the maintenance of the elements. There is also a striking and thus difficult to integrate external appearance.

So far The potential of concrete as a heat-storing building material only inadequate exhausted. The integration of transparent thermal insulation as a method of heat recovery from sunlight, and their forwarding via the house wall into the interior, has not prevailed widely. Created so far in connection with transparent thermal insulation usually large-scale glass facades, which, contrary to expectations, do not constitute an opening of the building, but rather are opaque.

at buildings in exposed concrete is the application of transparent thermal insulation so far a contradiction, mainly due to the usual constructive execution in core insulation, which prevents the transmission of the heat gained in the interior. But at the same time of course also due to the appearance of the outer shell of concrete, which by Glass would be replaced.

• – Das Dämmmaterial muss das einfallende Licht möglichst verlustarm bis zum Absorber weiterleiten (Transmissionsgrad) sowie insgesamt einen hohen Energietransmissionswert aufweisen.
• – Die Wärmeleitfähigkeit des Dämmmaterials sollte möglichst gering sein.
• – Die Wärmeleitfähigkeit der Wand sollte möglichst hoch sein.
• – Der Absorber muss einen möglichst hohen thermischen Absorptionsgrad aufweisen.
• – Das System muss dicht sein um einen Wärmeverlust nach Außen und Kondensationsfeuchte im Bauteilinnern zu verhindern. Fast alle Produkte auf dem Markt lösen dies durch eine Glasscheibe als abschließendes Element.

The principle of transparent thermal insulation is based on a reversal of the heat flow. In the case of a normal building, as much insulation as possible is used to give as little heat as possible to the outside. On the other hand, the transparent thermal insulation works like a heat trap and passes on the sunlight to a mostly black absorber layer, where the light is converted into heat energy. The wall is warmed up. The fact that this heat is passed on into the interior depends on the material properties of the insulation and the wall. The wall must be made of a material that conducts heat as well as possible (concrete or masonry are possible, for example), whereas the transparent thermal insulation must be made of a material which is as heat-imperfect as possible in order to prevent the heat being dissipated to the outside. This leads to the following prerequisites for a functioning system:

• - The insulating material must transmit the incident light as low loss as possible to the absorber (transmittance) and have a high overall energy transmission value.
• - The thermal conductivity of the insulating material should be as low as possible.
• - The thermal conductivity of the wall should be as high as possible.
• - The absorber must have the highest possible degree of thermal absorption.
• - The system must be tight to prevent heat loss to the outside and condensation moisture inside the component. Almost all products on the market solve this with a glass pane as a final element.

basic Requirements to apply such a system are a location with high radiation in winter and south - facing outer walls of the Building. The south facade must to be unshaded in the winter, but in the summer must be a shade ensures the transparent insulation be because the building is otherwise undesirable heating up. Most of the existing systems therefore have one in the insulating element integrated sun protection, often in the form of a roller blind. Just this Shading elements behind the glass plane and thus behind the level of tightness lie and as internal sunscreen func tioning, but require a relatively high maintenance and cause costs in case of a defect.

transparent thermal insulation are for the most part made of sensitive elements made of glass tubes or plastic honeycombs realized. Because these elements are installed with special care have to, this complicates the construction process. There are still relatively few specialist companies for a professional Installation.

Of the The present invention is therefore based on the object, a building element and / or a building available with wall elements to provide the solar radiation energy in an effective way heat recovery for the Use the interior of the building and / or contribute to improving the energy balance of the building can.

This task is done with the objects reached the independent claims. Features of advantageous developments of the invention will become apparent from the dependent claims. In particular, the invention is achieved with a solar wall element for heat recovery from solar radiation energy having the features of the preamble of independent claim 1. The solar wall element is used in particular for use as part of an outer building shell. It comprises a body and / or hollow body of at least partially transparent or at least translucent and / or light-conducting materials. Due to their material properties and / or due to their structural design, the materials have heat-insulating properties. With the present invention, a structurally very simple and completely dispensing with any moving parts and / or control devices component is provided, which can significantly improve the thermal energy balance and the energy balance of a building as an integral part of an outer building wall.

at a preferred embodiment of the solar wall element has a geometric wrapping element of the body in an outer area a reflective surface facing the inside of the element. In addition, the geometric envelope element of the body in an inner region having an absorbent cap on the energy of solar radiation is converted into thermal energy. The solar radiation can be either angle-selective in this way be forwarded to the absorber cap, or not reach and be reflected back again, based on the geometric shape of the element in conjunction with the reflective layer in the front area. Preferably exists at least between the absorber layer and the surrounding storage mass an intimate connection, what the improved heat introduction into the component serves.

Optional can also be an arrangement of several such solar wall elements according to a the embodiments described above be formed.

The The invention also relates to a building with at least one solar wall element according to one of the previously described Embodiments. in this connection if the wall element is completely or partially integrated in a heat-storable building envelope, however, such that at least one side of the body is disposed on the outer surface is that it is reached by the sunlight. Optionally, at a such building also several wall elements according to a the embodiments described above in at least one building exterior wall be arranged.

In summary It should be emphasized that the problems listed above for the construction process, the cost and maintenance by a translation of the principle of transparent insulation in an element that is in a concrete wall, a precast or in another Heat-storing Component is poured or used, for the most part solved or can be improved.

The The effect of the element is based on the following principle: sunlight meets a highly transparent or at least translucent body and gets into it. With the penetration becomes a portion of the Radiation in heat transformed. The remaining portion is replaced by a reflective surface in the area of the inner element envelope further in the body into steered. In the area behind, the inner surface is radiation absorbent coated. The heat absorbed in this layer becomes forwarded by an intimate connection to the concrete wall or storage mass. There it spreads and warms the component.

The Principle allows a temperature amplitude attenuation, first there is solar heat is stored in the wall and after several hours, normally about 6 to 8 hours later Out of phase is delivered to the interior. The generated large-scale heat dissipation a comfortable room climate. At the same time, operating and investment costs can be increased for the Saved heating system. Last but not least, the saved emissions benefit the environment.

Of the technical structure is as follows: The solar stone consists of a body made of plastic, glass or other transparent materials. Of the reflective area can be finished by surface treatment (polishing) or application of a reflective material (coating) become. The absorbing area can be achieved by surface treatment (matting, sand blasting) or by applying an absorbent Material (coating) are produced. The surface must robust and intimately connected to the solid component or the hollow body be. The component can be used as a single element in the concrete or the solid component be introduced. It can also by means of a die, which in the component remains or a grid or structural element are positioned.

Of the technical structure is not limited to the outlined dimensions, he Can also be applied to much smaller or larger dimensions of the solar stone body become.

The body of the solar stone is shaped in such a way that its geometry directs defined solar irradiation angles onto the absorbing surface or else defined Einstrahlwinkel reflected. Thus, heating of the component is enabled or prevented depending on the angle of incidence of the solar radiation. Depending on the location and the season, the geometry may vary.

The Optionally geometry can also be clearly distinguished from the sketched shapes differ. The principle may vary depending on the position of the sun, location and desired heat output be modified.

Of the Solar stone is preferably corresponding to a solid component thermal conductivity built-in. This can be a precast concrete element, an in-situ concrete wall or also a brick element or otherwise massive component. The massive In the area between the absorber and the inner surface of the component outer wall a thermal conductivity on that a heat flow towards the inner surface allows. The massive component has in the area between the absorber and the outer surface of the outer wall a thermal conductivity on that a heat flow minimized towards the outer surface.

Of the body of the solar stone, for example, made of cast Plexiglas be. Plexiglas has 92% higher light transmission than Glass. Its total energy transmission is 85%. Furthermore owns it has a relatively low thermal conductivity of 0.19 W / mK. Glass has compared over a thermal conductivity of 1.0 W / mK. The material is weather and aging resistant, good workable and withstands continuous use temperatures up to 80 ° C.

The Curved shape of the specimen in the Section and floor plan form a geometry that can be adapted to the location. Due to the inclination of the stone, the size of the light aperture as well the depth of the reflection surface is achieved that the radiation between 5-40 ° further reflected to the absorber will, higher Irradiation angle from 40 °, however, reflected back become. Here, the example of the sample body refers to the location Upper Bavaria. It was determined that the low solar radiation in the winter is within the heating period between 5 ° and 40 °. The sunshine outside the heating season, which the building undesirable would heat up, is over 40 °.

The Drop shape in the view is not mandatory. Other formulations of the element are conceivable as long as the previously described principle is followed in section and floor plan.

Of the towards the outside wall lying area of the sample body can, for example, have a metallic coating, for example. In the form an aluminum coating which has a total reflection of About 95% of the sunlight continues to reflect.

The absorber surface may be formed by a dark or black cap, for example, the z. B. may consist of copper sheet or steel. The shape of the Cap guarantees a larger surface than a level completion of the solar stone and thus guarantees a larger area transmission the heat the wall. The absorber potential of a black coating is 95%.

Of the pattern body is preferably poured into a concrete wall whose structural physical Properties through porous Shares (light aggregate from, for example, expanded clay spheres - Liapor and expanded glass granules - Liaver) and PCM materials (eg Rubitherm GR 27 or Micronal) in favor the process of heat flow and heat storage are optimized. The principle is also in deviating components applicable.

Further variants are conceivable. In addition to pouring In-situ concrete offers the production of prefabricated panels at. It allows a relieved pouring and a more accurate positioning of the solar elements. It should the solar stones are not completely shed, but the absorber caps still free. The precast panels can be considered as lost formwork be used, whereby it is ensured that the protruding from the plates Caps are poured into the in-situ concrete and thus a flawless heat transfer possible is. Furthermore, the installation in brick or aerated concrete components as an application possible.

meaningful can a solar area share of about 30%. This will cause an optical predominance of one of the two Prevents building materials. The percentage of solar stones the façade surface can vary according to need and appearance.

The effect of the solar stone is that it serves the use of solar gains to heat the component at defined seasons. For the exemplary calculation of the solar gains for the sample body, the location-based radiation offers were determined during the heating season. The locations Oberbayern and Chur were chosen. The following values for a wall structure of 45 cm and a solar area proportion of 30% were determined:
Concrete wall: u = 0.65 W / m ² K
Concrete + Plexiglas: u = 0,56 W / m ² K
Total: u = 0.62 W / m ² K

For the location of Upper Bavaria, the solar yields per m ² solar area (equivalent to 37 solar blocks) amounted to 219 kWh / a, for Chur 253 kWh / a.

The Solarstein uses the principle of obtaining heat energy from direct sunlight radiation. The recovered heat energy is introduced into the component and emitted to the interior of the surface facing the component. In addition, the heated component reduces the heat flow in the direction of the temperature gradient to the outside. Both effects reduce heat losses in the heating period and the attenuation of the temperature amplitudes produces optimized radiation over the course of the day.

The Geometry is designed so that solar gains only in certain Seasons (heating season) are registered. In seasons with middle and higher Temperatures are less or no heat input, causing unwanted heating or overheating of the component or the entire building is avoided.

The System is intended as a support to the Heating system It offers the novel possibility for exposed concrete structures implement the principle of wall heating. Compared to existing ones Products of transparent thermal insulation is The Solarstein an insensitive element, which during the Construction process is robust enough and durable. The materials are sustainable and have one long life span. The system works maintenance-free and continuously. It allows beside Energy efficiency improves the indoor climate Inside rooms, Overall, by applying the principle of solar stone heating energy saved from other energy sources.

Further Features, objects and advantages of the present invention will be apparent The following detailed description of a preferred embodiment the invention, which serves as a non-limiting example and on the attached drawing Refers.

1 describes the position of the solar elements in the component. The distance between the insert elements and the dimensions of the component and elements can vary.

2 clarifies the position of the absorber layer

3 clarifies the position of the reflective layer

4 shows schematically the solar irradiation angle in the course of the year.

5 shows exemplary prefabricated panels in section and view with a solar area of 30%.

An embodiment of a solar wall element according to the invention 1 is determined by the following 1 to 5 explained in more detail. The mode of action of the wall element 1 is based on the following principle: sunlight 2 meets a highly transparent or at least translucent body 3 and gets into it. With the penetration becomes a portion of the radiation 2 converted into heat. The remaining portion is due to a reflective surface in the region of an inner element envelope surface 4 further into the body 3 into steered. In the area behind, the inner surface has a radiation absorbing coating 5 on. The in this coating 5 absorbed heat is transmitted through an intimate connection to a concrete wall 6 or storage mass 7 forwarded. There it spreads and warms the component.

The exploded view of the 2 clarifies the position of the absorber layer 5 in the rear part of the front, ie to the outer wall 8th of the building (cf. 1 ) open body 3 , The exploded view of the 3 on the other hand illustrates the position of the reflective layer 4 that the front, tubular part of the body 3 envelops.

The technical structure can be as follows. The solar brick or the wall element 1 consists of a body 3 made of plastic, glass or other transparent materials. The reflective area 4 can be made by surface treatment (polishing) or application of a reflective material (coating). The absorbing area 5 can be produced by surface treatment (matting, sand blasting) or by applying an absorbent material (coating). The surface must be robust and intimately connected to the solid component or the hollow body. The component 3 can as a single element 1 in the concrete 6 or the solid component 7 be introduced. It can also be positioned by means of a die which remains in the component or a grid or structural element. The technical structure is not limited to the outlined dimensions, it can also be applied to much smaller or larger dimensions of the solar stone body.

The body of the solar stone or wall element 1 is shaped so that its geometry defines solar irradiation angles on the absorbing surface 5 deflects or other defined Einstrahlwinkel reflected. This will cause the component to heat up 1 depending on the angle of incidence of the solar radiation 2 allows or prevents. Depending on the location and the season, the geometry may vary. The geometry may differ significantly from the sketched shapes. The principle can be modified depending on the position of the sun, the location and the desired heat yield.

The solar stone 1 can be installed in a solid component of appropriate thermal conductivity. This can be a precast concrete element, an in-situ concrete wall or even a brick element or other solid component. The massive component points in the area between the absorber 5 and inner surface of the outer wall 8th a thermal conductivity that causes a heat flow towards the inner surface 9 allows. The massive component 1 points in the area between absorber 5 and outer surface of the outer wall 8th a thermal conductivity that causes a heat flow in the direction of the outer surface 8th minimized.

The in the 1 to 5 illustrated solar stone 1 is a sample body as an exemplary application of the principle. This consists of cast Plexiglas. Plexiglas has 92% higher light transmission than glass. Its total energy transmission is 85%. Furthermore, it has a relatively low thermal conductivity of 0.19 W / mK. In comparison, glass has a thermal conductivity of 1.0 W / mK. The material is weather and aging resistant, easy to machine and withstands continuous use temperatures up to 80 ° C.

The curved shape of the sample body in section and floor plan produces the geometry corresponding to the location. Due to the inclination of the stone, the size of the light opening and the depth of the reflection surface 4 it is achieved that the radiation continues between 5-40 ° to the absorber 5 is reflected, higher radiation angles from 40 °, however, be reflected back. Here, the example of the sample body refers to the location of Upper Bavaria. It was determined that the low solar radiation in winter in the heating period between 5 ° and 40 °. The sunlight outside the heating period, which would heat the building undesirable, is over 40 °.

The Drop shape in the view is not mandatory. Other formulations of the element are conceivable as long as the previously described principle is followed in section and floor plan.

The direction outer wall 8th lying region of the sample body has an aluminum coating 4 , which reflects the sun light with a total reflection of about 95%. The absorber surface 5 consists of a black cap z. B. copper sheet or steel. The shape of the cap guarantees a larger surface than a flat finish of the solar stone 1 and thus guarantees a larger-scale transfer of heat to the wall 6 , The absorber potential of a black coating 5 is 95%.

The pattern body is in a concrete wall 6 whose physical properties are optimized by porous components (lightweight aggregate of eg expanded clay spheres (Liapor) and expanded glass granulate (Liaver)) and PCM materials (eg Rubitherm GR 27 or Micronal) in favor of the process of heat flow and heat storage. The principle is also applicable in deviating components.

In addition to pouring into in-situ concrete, the production of prefabricated panels is also suitable. It allows easier pouring and a more accurate positioning of the solar elements 1 , It should be the solar stones 1 not completely shed, but the absorber caps 5 still be free, like this in 5 is shown. The precast panels 10 with a plurality of wall elements embedded therein 1 can be used as a permanent formwork, making sure that from the plates 10 protruding caps 5 poured into the in-situ concrete and thus a perfect heat transfer is possible. Furthermore, installation in brick or aerated concrete components is possible as an application.

In the illustrated examples of semi-finished parts (see. 5 ), a solar area share of 30% was chosen. As a result, an optical predominance of one of the two building materials is prevented. The percentage of solar stones 1 on the facade surface can vary according to need and appearance.

The solar stone according to the invention 1 serves the use of solar gains to heat the component at defined seasons. For the exemplary calculation of the solar gains for the sample body, the location-based radiation offers were determined during the heating season. The locations Oberbayern and Chur were chosen. The following values for a wall structure of 45 cm and a solar area proportion of 30% were determined:
Concrete wall: u = 0.65 W / m ² K
Concrete + Plexiglas: u = 0,56 W / m ² K
Total: u = 0.62 W / m ² K

For the location of Upper Bavaria, the solar yields per m ² solar area (equivalent to 37 solar blocks) amounted to 219 kWh / a, for Chur 253 kWh / a.

The four representations of 4 show schematically the solar irradiation angle during the year. The drawings a) and b) represent the situation in winter during the heating season. The drawings c) and d) represent the situation during the summer months.

The principle allows a temperature amplitude attenuation, since first solar heat is stored in the wall and is discharged about 6-8 hours later out of phase to the interior. This generates the large-scale heat dissipation a comfortable room climate. At the same time operating and investment costs for the heating system can be saved. Finally, the saved emissions benefit the environment.

Of the Solar stone is a principle for the production of heat energy from direct sunshine. The recovered heat energy is introduced into the component and facing the interior surface of the component radiated. About that Beyond is heated by the Component of heat flow in the direction of the temperature gradient outward reduced. Both effects reduce heat losses in the heating season and by the damping the temperature amplitudes are optimized in the daytime course Radiation.

The Geometry is designed so that solar gains only in certain Seasons (heating season) are registered. In seasons with middle and higher Temperatures are less or no heat input, causing unwanted heating or overheating of the component or the entire building is avoided.

The System is intended as a support to the Heating system It offers the novel possibility for exposed concrete structures implement the principle of wall heating. Compared to existing ones Products of transparent thermal insulation is The Solarstein an insensitive element, which during the Construction process is robust enough and durable. The materials are sustainable and have one long life span. The system works maintenance-free and continuously. It allows beside Energy efficiency improves the indoor climate Inside rooms, Overall, by applying the principle of solar stone heating energy saved from other energy sources.

The The invention is not limited to the above embodiments. Much more is a variety of variants and modifications conceivable by the idea according to the invention Use and therefore also fall within the scope of protection.

1

wall element

2

sunlight

3

body

4

inner Envelope / reflective layer

5

absorbing Coating / absorber cap

6

concrete wall

7

storage mass

8th

outer wall

9

palm

10

Precast concrete slab

Claims (8)

Solar wall element ( 1 ) for heat recovery from solar radiation energy ( 2 ), in particular for use as part of an external building envelope, comprising a body ( 3 ) and / or hollow body of at least partially transparent or at least translucent and / or light-conducting materials, characterized in that the materials have heat-insulating properties due to their material properties and / or due to their constructive structure. Solar wall element according to claim 1, characterized in that a geometric envelope element of the body ( 3 ) in an outer area one to the inside of the element ( 1 ) reflective surface ( 4 ) having. Solar wall element according to claim 1 or 2, characterized in that the geometric envelope element of the body ( 3 ) in an inner region an absorbent cap ( 5 ) for converting the energy of solar radiation into heat energy. Solar wall element according to one of claims 1 to 3, characterized in that the solar radiation ( 2 ) angle selective either to the absorber cap ( 5 ) or is not reached and reflected back, based on the geometric shape of the element ( 1 ) in conjunction with the reflective layer ( 4 ) in the front area. Solar wall element according to one of claims 1 to 4, characterized in that at least between the absorber layer ( 5 ) and the surrounding storage mass ( 7 ) There is an intimate connection, for heat introduction into the component. Arrangement of several solar wall elements ( 1 ) according to one of claims 1 to 5. Building with at least one solar wall element according to one of claims 1 to 5, characterized in that the wall element ( 1 ) is fully or partially integrated in a heat-storable building envelope, but such that at least one side of the body ( 3 ) so on the outer surface ( 8th ) is arranged to be away from sunlight ( 2 ) is achieved. Building according to claim 7, characterized in that several wall elements ( 1 ) according to one of claims 1 to 6 in at least one building exterior wall ( 8th ) are arranged.