DE202007005302U1 - Collector e.g. hybrid collector, for generating electrical and thermal energy from solar energy, has photovoltaic module and solar thermal module arranged in common housing, where insulation space is arranged between two modules - Google Patents

Abstract

The collector has a semitransparent photovoltaic module arranged in a common housing, where the photovoltaic module is formed by an upper part of the collector. A solar thermal module is arranged in the common housing, where the solar thermal module is formed by a lower part of the collector. An insulation space (4) is arranged between the photovoltaic module and the solar thermal module. The photovoltaic module is formed from a transparent carrier (1), where a photovoltaic unit is arranged at an inner side of the photovoltaic module.

Description

The The invention relates to a collector semitransparent design for Generation of electrical and thermal energy from exclusively solar radiation energy.

Under Solar thermal systems are technical systems for the heating of Heating and service water with the help of solar radiation energy. These usually consist of collectors, a connecting piping system, a heat transfer medium and a storage tank with heat exchangers for hot water. There are also measuring, control and regulating devices.

The heart such a plant form the collectors. Here are basically two Types available.

To the one of the vacuum tube collectors, which consists of evacuated glass tubes consists.

in the Inside the tube there is a second tube or tube system, the actual absorber surface represents and from the heat transfer medium is flowed through.

The inner tube is specially coated and is the focus of laterally mounted Reflect. This type of collector can deliver very high temperatures and has a high efficiency. He is very expensive and not for design reasons a combination with photovoltaic suitable.

Of the second collector type is the so-called flat collector. This guy consists of a specially coated aluminum or copper foil, at the back a pipe system, preferably of aluminum or copper, meandering or harp shaped is applied.

To the Protection against environmental influences is this collector with a glass plate or similar transparent materials covered at the top.

These Cover leaves the radiation emitted by the sun almost lossless through. The under the absorber surface applied piping system is traversed by a heat transfer medium and thus transports the heat towards the storage system. The heat transfer medium is usually a water-glycol mixture used for frost damage submissions.

photovoltaics refers to the direct conversion of solar radiation into electrical Energy due to the release of charge carriers in solids.

For this be according to the state The technique used semiconductors, i. Fabrics close to the absolute Isolate the zero point of the temperature, but at higher temperatures, more targeted disorder of the crystal lattice or by external energy input conductivity gain.

Around Architectural concerns such as optics, thermal insulation, shading, aesthetics and glare control in conjunction with photovoltaics, have been so-called semi-transparent solar modules for some time for the Building Integration (GIPV) available.

in this connection they are preferably thin-film cells, in particular amorphous, polycrystalline or even CIS cells.

Thereby Is it possible, Produce PV modules with 1% to 99% light transmittance. In concrete means that the photovoltaic part can be freely scaled.

So facades are possible which absorb 90% of the light in certain places and others Make only 10%, with all modules but the same output voltage have to conventionally interconnect them.

These Semitransparent cells have a variety of problems. That's the stability of the cells during the manufacture and the introduction of the breakthroughs in the Wafer is a particular risk factor that makes mass production difficult designed.

The Problems with semitransparent cells with inserted between glass plates Wafers are more of a visual nature.

These Technology leaves only light in small areas, due to the used Wafer the remaining areas throw big shadows. Another one The problem is the use of expensive silicon wafers and the high weight due to two glass plates used.

According to the state technology becomes solutions proposed which the known photovoltaic assemblies with those of solar thermal connect so that a heat transfer from the heated ones Wafern by direct contact by heat conduction to the solar thermal Module is made.

This results in disadvantages in terms of tightness of the solar thermal module in conjunction with the electrically conductive photovoltaic module and the feedback of the thermal conductivity of the photovoltaic module to the absorber and order swept in changing weather conditions.

Of Another disadvantage is that all in the combined collector used materials have different thermal expansion coefficients and thus mechanical problems can occur in the system.

Of Another is the direct connection between the solar thermal collector and the semitransparent PV module associated with high thermal losses, because heat energy by direct contact of the solar thermal absorber to the PV cells and thus released to the environment.

task The invention is known problems of tightness and foreclosure Solarthermiekollektors the photovoltaic elements to solve to avoid short circuits, To minimize thermal losses, and the known disadvantages of the prior art.

Of Furthermore, the resulting loss of efficiency in the combination of Photovoltaic and solar thermal minimize as well as the mechanical To eliminate problems.

The solution the task of the invention arises from the characterizing features of claim 1 in Connection with the characteristics of the generic term. Further advantageous Embodiments of the invention will become apparent from the dependent claims.

The collector of the invention will be described below with reference to the 1 and 2 be explained in more detail.

The collector according to the invention consists of a housing 9 , which forms the bottom and the side walls of the collector and receives all other components and components of the collector and a transparent support 1 , which closes the collector at the top and at the same time forms a protection against external influences from this direction.

alternative can the solar thermal collector in the double chamber profile with vacuum accomplished be, or evacuated the interior of the housing as such be.

By means of a sealing carried out according to the prior art 10 are housings 9 and transparent carrier 1 connected with each other.

The upper part of the collector according to the invention forms a semitransparent photovoltaic module 11 while the lower part of the collector is a solar thermal module 12 equivalent.

At the bottom and thus inside of the transparent carrier 1 are photovoltaic elements 2 arranged, which preferably by means of a transparent fixing layer for PV elements 3 on the inside of the transparent support 1 be fixed.

These photovoltaic elements 2 According to the prior art, semitransparent hybrid collectors are arranged such that they cover only a part of the irradiation surface and thus allow solar radiation into the collector.

Below this fixing layer 3 is an isolation space according to the invention 4 arranged, which is executed in its depth according to the specific territorial requirements or the transmittance of the semitransparent photovoltaic module 11 was adjusted.

The height of the isolation room 4 is determined by the degree of transparency. Measurements have shown that it is advantageous to increase the height of the insulation space, if the degree of transparency is increased, since the effect of the PV layer as a thermal shield was only limited detectable here.

Increases the proportion of photovoltaics, the degree of transparency decreases. Here It is advantageous to reduce the distance, as the PV layer acts as a thermal shield and additionally the heated photovoltaic cells Heat by means of Heat radiation at transfer distance to the absorber layer more easily.

The isolation room 4 closes an absorber 5 , preferably with an effect-improving coating, a pipeline 6 for the medium carrying the heat energy, a reflection layer 7 and an insulation disposed thereunder 8th at.

Likewise, the reflection layer 7 be arranged as Absorbtionsschicht and the insulation 8th gets a reflection layer.

The photovoltaic elements 2 emit heat energy into the interior of the collector, since the outer semitransparent photovoltaic assembly form a thermal shield due to a higher temperature potential than the solar thermal absorber, which prevents heat loss to the environment.

Thermalization is a loss mechanism that means extreme heating of the cells. The heating caused by the infrared portion of the sunlight produces so-called lattice vibrations. These in turn ensure that photons not involved in the charge separation process are more likely to collide with the lattice structure. These photons, with energy larger than the energy gap, excite charge carriers to states that are above the band edge. The difference between energy of the excited state and the energy of the band edge is given as thermal energy to the crystal lattice.

The photovoltaic assembly thus has in operation for comparison with the absorber 5 a higher temperature, whereby a heat dissipation in this direction is prevented.

The isolation room 4 , which prevents convective heat loss, but lets heat radiation through, defines the distance of the photovoltaic assembly to the installation direction under the insulation space 4 arranged solar thermal assembly.

Will the isolation room 4 maximized in height, increases the electrical efficiency of the photovoltaic assembly, as less heat energy from the solar thermal absorber 5 to the semitransparent PV module 2 is transferred.

Will the isolation room 4 minimized in height, so is a higher heat transfer from the solar thermal assembly 5 in the photovoltaic module 2 realized and the electrical efficiency is minimized because the operation of photovoltaic elements over standard test conditions of 25 ° C cell temperature is lossy.

Thus, it is possible by means of the selection of the height of the isolation space 4 to set the collector according to the invention according to the respective needs.

ever after the appropriate request, a setting after the respective demand for electrical energy or heat energy take place.

This is done by choosing the distance between solar thermal absorber 5 and the photovoltaic module 2 Another option is to select the degree of transparency of the photovoltaic module 2 ,

Also included among the scope is the possibility of elimination of the transparent fixation layer 3 if the photovoltaic layer 2 in a different way with the transparent carrier 1 is connected.

Below is the solution of the invention based on embodiments and the 3 to 6 be explained in more detail.

An embodiment of the invention is in 3 shown. Here, for example, a transparency of 60% of the total surface is shown.

This is distributed by the evenly distributed Arranging silicon wafers or by large-scale deposition of thin-film solar cells, which subsequently by appropriate procedures in many individual photovoltaic areas are achieved.

The degree of transparency is advantageously freely scalable in the case of thin-film technology, whereas the degree of transparency is determined by the size of the wafers used when silicon wafers are used. So can, as in 3 By using 5 inch wafers, a degree of transparency of 60% can be achieved, whereas 6 inch wafers achieve a degree of transparency of 30%, as in 4 shown.

The Determining the transmittance can also be done by a local photovoltaic sector and a transparent sector become. An advantageous design of the solution according to the invention can For example, consist in the photovoltaic part in one Concentrate part of the collector.

It would be again advantageous to arrange the photovoltaic part below, as in 5 shown.

One positive effect would be this is a lower thermal load of the photovoltaic Cells at standstill or low heat loss, as a solar thermal collector Due to the design, the lowest heat development has at this point.

in the In contrast, you can also choose an opposite flow, creating a other distribution of photovoltaic elements is made possible.

6 shows a prior art solar thermal collector. This is changed by the fact that the transparent layer 1 is replaced by a corresponding semitransparent photovoltaic carrier layer.

Thereby is it possible to retrofit already installed solar thermal collectors so that created a collector according to the inventive solution becomes.

Claims (15)

Semitransparent collector for generating electrical and thermal energy exclusively from solar energy, characterized in that in a common housing forming the upper part of the collector a semitransparent photovoltaic module ( 11 ) and not mechanically connected to each other forming the lower part of the collector is a solar thermal module ( 12 ) and between these modules an isolation space ( 4 ), which allows convective heat losses to prevent thermal radiation, and the collector to the irradiation direction by means of a transparent support ( 1 ) is closed. Collector according to claim 1, characterized in that the photovoltaic module is formed of a transparent support ( 1 ), at the bottom and thus inside photovoltaic elements ( 2 ) are arranged. Collector according to claim 1, characterized in that the solar thermal module is formed from an absorber ( 5 ), a pipeline ( 6 ) for the medium carrying the heat energy, a reflection layer ( 7 ) and an insulation ( 8th ). Collector according to claim 3, characterized in that the absorber ( 5 ) is provided with a coating improving its effect. Collector according to claim 4, characterized in that the coating of the absorber ( 5 ) works selectively and thus solar radiation completely through and from the absorber ( 5 ) emitted infrared heat radiation in the absorber ( 5 ) throws back. Collector according to claim 1, characterized in that the insulation space ( 4 ) in its depth according to the special territorial requirements. Collector according to claim 1, characterized in that the insulation space ( 4 ) in depth according to the transmittance of the photovoltaic elements ( 2 ) is to vary. Collector according to claim 1, characterized in that the insulation space ( 4 ) in depth according to the transmittance of the photovoltaic elements ( 2 ) and the specific territorial requirements. Collector according to claim 1, characterized in that the Achieving the transparency of the photovoltaic module the applied Solar cells are arranged at a distance. Collector according to claim 1, characterized in that the applied solar cells are crystalline silicon solar cells. Collector according to claim 1, characterized in that behind the solar cells of the photovoltaic element of the absorber ( 5 ) has no coating and thus radiant energy from the photovoltaic element 2 to absorb. Collector according to claim 1, characterized in that the reflection layer ( 7 ) as the absorption layer and the insulation ( 8th ) is provided with a reflection layer. Collector according to claim 1, characterized in that the absorber ( 5 ) is provided with a selective coating to minimize the heat losses to the environment. Collector according to claim 1, characterized in that the transparent layer ( 1 ) of a solar thermal collector is replaced by a corresponding semitransparent photovoltaic support layer. Collector according to claim 1, characterized in that the Collector a local photovoltaic sector and a transparent Sector.