Note: Descriptions are shown in the official language in which they were submitted.
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STRUCTURE WITH TRANSPARENT ENCLOSING SURFACES
Structures havin~ large and often predominantly transparent enclosing surfaces
are usually known as conservatories and solariums but may also, for example,
include greenhouses.
5 Conservatories and solariums are usually glassed-in extensions attached to onewall of a building and they enclose self-contained rooms which are
interconnected with the rooms of the building situated to the rear of the
structure. In these glassed-in extensions, the non-transparent enclosing
surfaces are formed by the adjacent walls of the building and the floor of the
10 structure. On the other hand, in the case of greenhouses only the floor is a
non-transparent enclosing surface.
It is characteristic of such structures with transparent enclosing surfaces that,
depending on the angle of arrival of the incident solar energy, the latter enters
into the structure by passing through a transparent enclosing surface and then
15 emerges from the structure either directly by passing through an opposite
enclosing surface or it is reflected in all directions by surfaces located inside
the room. Sunlight therefore to a large extent passes through such structures.
Glassed-in extensions have been enjoying increasing popularity especially in
recent years. This is probably due on the one hand to the opportunity they
20 offer to experience an unimpeded view of the surroundin~ world while
remaining protected from climatic conditions, and on the other hand their
popularity is due to people's need for sunshine and the warmth of the sun.
Glassed-in extensions are regarded as thermal buffer zones for the attached
buildings or also as passively heated solar collectors whose thermal energy
25 passes into the adjacent living spaces via room-air convection. However, it has
been found that the thermal benefits of such glassed-in extensions fall far short
of meeting the physical expectations placed in them by their designers.
~ ........... . . . .
Measurements conducted on experimental structures have revealed that in the
most favourable of cases the attached buildings save no more than up to 15%
heating energy. But also, cases were found in which a negative thermal
balance existed and where the benefits of the glassed-in structures, which
5 were erected to compensate for winter heat losses, were limited merely to the
additional living space that was gained and to the experience of living close tonature.
In general, the limited habitability of rooms having large or predominantly
transparent enclosing surfaces has proved to be disadvantageous. In order to
10 ensure that such glass-enclosed spaces remain habitable in the summer months
it is usually necessary to provide which afford protection from the sun and
which ventilate the structure. In the winter months, on the other hand, and in
many instances also in the transitional periods between seasons, it is necessaryto provide heat by means of additional heating systems even when highly
15 efficient sealed double-glazing units with heat transmission values of, for
example, k < 1.2 W/qmK are used.
In view of these inadequate--aspects of the current state of the art, the
underlying task of the invention is to design structures with lar0e and
predominantly transparent enclosing surfaces, such as conservatories or other
20 glassed-in extensions, but also greenhouses, which are rendered pleasantly
habitable in the transitional periods between the seasons and in particular ~ -during the winter by efficient conversion of the incident radiant energy from
the sun, without it being necessary to interfere with the architectural
appearance of the structure. According to the invention, therefore, the energy
25 characteristics of glassed-in extensions would be optimized and the structures
would be designed in such a way that they form efficient facilities for capturin~
solar radiant ener0y and thermally converting it in any adjacent rooms.
This task is solved in the following manner: In a structure havin~ one room,
which is at least partially enclosed by transparent surfaces, in particular a
~O glazed extension in the form of a conservatory, a solarium or similar, the
transparent enclosing surfaces are equipped with filters which for the most part .
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selectively absorb the non-visible spectral components of the incident solar
energy and convert them into long-wave thermal radiation, while allowing the
visible components of the solar radiation for the most part to pass through
unimpeded.
5 The object of the invention is thus, in particular, by means of selectively
absorptive filters in the enclosing element, to convert into long-wave thermal
radiation the non-visible components of the short-wave solar radiation
impinging on a structure, right at the moment when the solar radiation passes
through the transparent enclosing surface. The transparent surfaces enclosing
10 the room are approximately opaque to the solar energy entering the room in the
form of long-wave thermal radiation. If the entire transparent enclosing surfaceof a glassed-in extension is equipped with absorptive filters, the non-visible
portions of the incident solar energy are almost totally absorbed. This is what
happens in particular in the case of glassed-in extensions in which the incident15 solar radiation passes through two sets of filters as it travels through the
structure.
Since glass is opaque to long-wave thermal radiation, almost 50 % of the solar
energy passing through such glassed-in extensions remains inside the
transparently enclosed space. This is in particular the case when, in
20 accordance with a further embodiment of the invention, the transparent
enclosing surfaces are equipped on their outer sides with a coating which
reduces the emission of thermal radiation.
Such a coating, which is transparent to the solar spectrum, is thermally
beneficial iri two ways. On the one hand it reduces the emission back into the
25 outside world of the thermal energy which is absorbed as the solar radiation
passes through the transparent enclosing surface; and, on the other hand, it
brings about a general increase in the thermal resistance of the glass enclosingsurfaces of the structure.
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The coating which reduces the emission of thermal radiation may
advantageously be a tin oxide coating which is pyrolytically applied to the
transparent enclosing surfaces.
Such coatings are preferably applied to the surfaces which are exposed,
5 without protection, to the external atmosphere because the coatings possess
excellent scratch resistance and are resistant to aging. On the other hantl, in
the case of coatings which are protected against abrasion, such as coatings
applied to the inner surfaces of the two panes of glass in sealed double glazin~units, it is possible to use less resistant semi-conductor or metal coatings
10 applied as a vapour in a vacuum and having induced transmission in the visible
spectral range; or also structural coatings of organic substances may be
applied; these latter coatings generally possess a lower emissivity than the
pyrolytically applied tin oxide coatings.
Within the scope of the invention, the absorptive filters may be designed in
particular as panes of glass or plastic having a core which is coloured or ;
enriched with selectively absorptive substances and through which the visible
spectral components of solar energy can pass substantially unimpeded. The
absorptive filters may also, however, take the form of selectively acting
coatings of inorganic or organic material which are applied to the sides of the
20 transparent enclosiny surfaces facing inwards to the enclosed space. ~ ~ u
Within the scope of the invention the transparent enclosing surfaces may also
take the form of composite elements having at least two panes joined to~ether
with on another at their surfaces by means of an adhesive foil.
Advantageously, one of these panes is an adsorptively acting filter panel and
25 the other pane is equipped on the side facing away from tne filter panel with the coating which reduces the emission of thermal radiation.
As an alternative to designing the enclosing surfaces as composite elements
having an adsorptively acting filter panel, the adhesive layer between the two
panes may also be formed as a filter layer which selectively absorbs solar
30 radiation in the non-visible range. Selectively absorptive, inorganic or organic
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pigments may be embedded in the adhesive foil or the adhesive foil may be a
compound foil having an integral, embedded filter foil containing inorganic or
organic pigments.
It has proved particularly advantageous to design the large-area transparent
5 enclosing surfaces of greenhouses and glassed-in extensions as sealed glazing
units having two or more panes, which are very effective thermal insulators.
Advantageously, the panes facing towards the enclosed space are designed as
absorptive filter panels while the other panes are made of material which is
highly transparent to the sun's rays.
10 When the panes of material which are highly transparent to solar radiation are
made of glass, it has proved particularly advantageous according to a further
embodiment of the invention to use clear, colourless flint glass because this
type of glass is more transparent to the solar spectrum than conventional
window glass.
15 Flint glass is a glass having an extremely low iron oxide content; in the visible
range of the solar radiation spectrum the glass causes a barely perceptible
increase in transparency, but in the non-visible, short-wave, infrared spectral
ran~e the transmissivity for solar energy radiation is increased by approximately
10 %. Up until now, such glass has only been used as the covering glass of
20 solar collectors.
~ :
So far, in the case of structures having transparent enclosing surfaces, the
benefits of such special glasses have by no means been appreciated because
they only marginally increase the transparency to light; on the other hand, in
the summer months they can increase the already excessive input of radiation
25 energy, which is barely tolerable unless measures are taken to protect against
the sunshine.
A double-pane, highly efficient thermal glazing system helps to achieve
considerable heat gains in a glass-enclosed space. This is of considerable
benefit to the habitability of the space both in the transitional seasons of the
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year as well as in the winter months. In the summer on the other hand, when
glass-enclosed spaces can easily become uninhabitable due to excessive heat
build-up in strong sunshine, an effective protection against solar radiation is
required and this usually takes the form of a sun blind.
5 According to another important embodiment of the invention, the enclosing
surfaces are inclined outward from the ground up. The angle of inclination
from the vertical is less than 30 and preferably between 10 and 15.
Such a measure has proved particularly advantageous in that, in the case of
summer solar radiation, a large part of the directional solar radiation which
10 impinges at a steep angle, is reflected away from the structure due to the
phenomenon of total reflection. On the other hand, under winter conditions,
because of the low angle of incidence of the sunlight, almost all of the
directional solar energy radiation passes through into the structure. Also, the
diffuse radiation input is increased by reflection from the surface of the ~round,
15 particularly when snow has fallen.
.
When the panes are inclined to the surface of the ground, the radiant heat
losses from the room are reduced. In view of the hemispherical radiation, the
surfaces of the ground and of the surrounding buildings or of the surrounding
vegetation play a greater role as radiation partners of the panes. These
20 radiation partners have an incomparably higher radiation temperature than the extremely cold sky.
Compared also with the outdoor air in the winter months, the surfaces of the
ground and the surfaces of surrounding buildings usually have a much hisher
temperature level because of the solar radiation received during the day and
25 because of their ability to store this heat during the night. The same applies
also to layers of snow in winter time.
::
Another important advantage of the invention is that, according to another ~-
embodiment, the transparent enclosing surfaces are desiyned as reversible ~ ~
.... . . .
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elements and may be adjusted as desired with one or the other of their sides
facing towards the enclosed space or towards the outside.
Thus, by designing the enclosing surfaces as reversible elements it is possible,during the seasons of the year when there is no need to convert solar energy
5 into heat, to protect a structure enclosed by transparent enclosing surfaces
from excessive insolation by turning the enclosing surfaces so that the sides
which face inwards during the transitional seasons of the year and in winter
now face outwards.
Because a selective filter pane which absorbs primarily the non-visible solar
10 spectrum is coated on one side with a coating which is transparent for short-wave solar radiation, but reduces the emissions of long-wave thermal radiation,
the pane performs the function of a dark glass protecting against the sun when
it is rotated by 180 compared with the position it occupies durin~ winter
operation. Once the pane has been reversed, the emission-reducin~ coating is
15 positioned on the rear surface of the filter pane relative to the direction of the
incident sunlight, i.e. on the side facing towards the enclosed space. In turn,
the non-visible portion of the incident solar radiation is absorbed by the filter
pane, as happens during winter operation. The thermal energy ~enerated in the
filter pane is then for the most part radiated outwards because of the emission-
20 reducing coating which is positioned to the inside, facing the room.
When sealed double glazing units are used for the enclosing surfaces ofglassed-in structures, this effect is naturally considerably enhanced because
the air or gas layer enclosed between the panes forms a thermal barrier for
heat transfer via convection and thermal conductivity, without affecting the
25 specific energetic radiation functions. The thermal barrier function of a sealed
double-glazed element thus has proved to be extremely advantageous both in
the winter and in the summer positions of the pane.
One embodiment of a structure according to the invention, having transparent
enclosing surfaces, as well as various means of configuring these enclosing
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surfaces, will now be explained on the basis of the attached drawing, which ~ -
contains the following diagrammatic views: ~ -
Fig. 1 shows a conservatory designed as a glassed-in extension, with
transparent enclosing surfaces attached to a fixed structure.
Fig. 2 shows a monolithic transparent panel element with a two-layer
coating. ~ -
Fig. 3 shows a transparent enc!osing element in the form of a
monolithic coloured filter pane made of glass or plastic and having
a coating which reduces the emission of thermal radiation.
~ - .
Fi~. 4 is a transparent enclosing element in the form of a colourless
window glass or float glass having a selective filter coating on - ~ -
one side and a coating which reduces the emission of thermal
radiation on the other side. ~ ;
Fig. 5 shows a transparent composite enclosin~ element built up of two
colourless glass panes joined together with one another by means
of an adhesive foil.
Fig. 6 shows an enclosing element also designed in the form of a
composite element, in which one of the panes is designed as a
filter pane and
.
20 Fig. 7 shows an enclosing element designed as a sealed double-glazed ~ -
unit with two panes spaced a certain distance apart.
~, ...
The conservatory 10 illustrated in Fi3. 1 is a glassed-in extension attached to
a wall 11 of a fixed structure 12; it comprises a skeleton framework, which is -
not of any further interest here, and transparent enclosing surfaces mounted
25 in this framework structure. The glassed-in extension possesses in each case
two sidewalls 13, 13' extending at a right angle from the wall 11 of the
.
. .. - . . - . - .
. . .
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structure 12 and a longitudinal wall 14 runnin~ at a distance from this wall of
the structure, as well as a roof surface 15 inclined at an angle from the wall
11 of the structure down to the longitudinal wall 14 of the conservatory. The
roof surface consists of several roof trusses 16 spaced a certain distance apart5 and running parallel to each other, between which is fitted an enclosin~
element 17 which closes off the upper side of the room enclosed by the
glassed-in porch. The sidewalls 13, 13' and the longitudinal wall 14 running
parallel to the wall 11 of the structure are formed from casement elements 18
which can be pivoted by 180 around a vertical axis between a summer and
10 a winter position; the transparent enclosure elements, which will be described
in detail below, are fitted in the frames 19 of these casement elements.
The enclosing element illustrated in Fig. 2 is a monolithic panel element 20
comprising a transparent pane 21 and a two-layer coating made up of the
layers 21, 23. The coating 22 is applied directly to the pane and performs a
15 selective absorption function, while the second layer is applied on top of the
absorptive layer and takes the form of a low-E coating which reduces the
emission to the outside atmosphere of the thermal energy captured by the
selective absorbing layer 22.
In such panel elements with a two-layer coating, care should be taken to
20 ensure that the coating is always applied to the panel element in such a way
that the low-E coating 23 is applied on top of the absorption layer 22 (also
referred to as a filter), which in turn is applied directly to the pane 21.
, .
The enclosing element 25 shown in Fig. 3 is a monolithic coloured filter pane
26 having applied to one side of it a low-E coating 27 which reduces the
25 emission of thermal radiation. The monolithic coloured filter pane may be a
pane of pre-tensioned or partially pre-tensioned glass or it may also be a pane
of plastic material. When an unprotected coating is applied to monolithic glass
panes, it is recommended to use hard cover coatings which consist of tin
oxide-based coatin~s applied pyrolytically to float glass.
~,, .
, . .. , ., . . . ~ . . - . . .
2 1 1 0 8 3 0
The enclosing element 30 illustrated in Fig. 4 comprises a pane 31 of highly
transparent colourless flint glass containing extremely low amounts of iron
oxides. On one side, this enclosing element is provided with a selective filter
layer 32, consisting of inorganic or organic substances, which absorbs
5 disproportionately high amounts of solar radiation in the non-visible range. The
other side of the glass pane is provided, in a similar manner to that used for the
enclosing element according to Fig. 3, with a low-E coating 33 which reduces
the emission of thermal radiation.
Instead of using a pane of colourless flint glass 31, it is also possible to use a
10 transparent plastic panel which may then incorporate appropriately acting
pigments. When a transparent plastic panel equipped in this manner is used
it is not necessary to apply the selective filter coating which absorbs solar
radiation in the non-visible ranges, and the coating on the other side of the
pane may be a layer of semi-conductor material or noble metal, preferably
15 covered with an extremely thin protective layer of plastic film through which thermal radiation can pass.
The composite element 35 illustrated in Fig. 5 consists of two colourless glass
panes 36, 37, which are joined together with one another by means of a
composite adhesive foil 38 designed as a filter layer. For this purpose,
20 selectively absorptive inorganic or organic pigments are embedded in the
composite adhesive foil. Alternatively, the adhesive foil may also be a
composite foil incorporating a filter foil in which inorganic or organic pigments
are embedded. On the side facing away from the adhesive foil the pane 36 is
provided wi~h a low-E coating 39.
25 The composite element 40 shown in Fig. 6 possesses a pane of glass or plasticmaterial, of the type described above in connection with Fig. 3, designed as a
colour filter 41 which is connected over its entire surface to a pane 43 of
colourless flint glass using a PVB or PU adhesive foil 42. A low-E coating 44,
of the kind already dealt with above in connection with Figs. 2 to 5, is in turn30 applied to the other side of the pane of colourless flint glass.
.. , .' .
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The enclosing element 45 seen in Fig. 7 is a sealed double-glazed element
having two panes 46, 47 arranged at a certain distance from each other and
containing an inert gas filling in the space 48 enclosed between the panes.
Again, as in the embodiments illustrated in Figs. 3 and 6, one of the outer
5 panes is designed as a coloured filter in the form of a pane of glass or plastic
material 46 having a low-E coating 49 on the side facing the space between
the panes. In contrast, the other pane 47 is designed as a pane of colourless
flint glass which is held at a certain distance from the other pane in the manner
indicated by the spacer section 50. The components 22, 26, 32, 38, 41, 46
10 are also cumulatively referred to as "filters". The aforesaid components 23,
27, 33, 39, 44, 49 are cummulatively referred to as "a coatin~"
:
The panel elements described above in connection with Figs. 2 to 7 may be
used individually, but they may also be combined, for example into composite
panes or sealed double-glazed units. In each case, care should be taken to
15 ensure that the low-E coating remains open to the surrounding atmosphere, i.e.
forms the outer or non-covered surface of a monolithic panel element. An
exception from this rule is permitted only if this coating is possibly covered
over by a protective coating which, like air or inert gas, is permeable to thermal
radiation in the wavelength range from 2.5 I~m to 15 ~Im. This requirement is
20 met, for example, by certain relatively wear-resistant plastic materials such as
polyvinyl chloride applied in a thickness of less than 50 IJm.
Fig. 1 shows one of the casement elements 18, which can be pivoted by 180
around a vertical axis between a winter and a summer position, in the open
position in the longitudinal wall 14 of the conservatory 10. In the winter
25 setting the pivoting elements are adjusted in such a manner that the filter
coatings or filter panes in each case face towards the room, behind the low-E
coatings, which are on the side facing the incoming solar radiation, so that the ~ -
thermal energy induced in the filter layers is primarily emitted into the room.
On the other hand, in the summer setting the pivoting elements are rotated by
30 180 around their vertical axes so that the filter layers or filter panes are facing
the incoming solar radiation in front of the low-E coatings, which then face
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inwards towards the room. In this settin~ the thermal ener~y induced in the
filter panes is primarily emitted to the outside and in addition is also removed :
convectively to the outside.
.
