Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Partition and method for controlling the temperature in an area
The present invention relates to a partition for separating two areas,
comprising two
translucent separation walls located a distance (a) of more than 5 mm apart,
wherein means
are provided for moving a liquid between said separation walls, said means
comprising
liquid dispensing means arranged to provide a liquid film, wherein one of said
separation
walls is an external separation wall and the other of said separation walls is
an internal
separation wall, wherein said liquid film moves over said internal separation
wall.
In US 4 2~6 576 A a vertically positioned panel for a solar collector with two
spaced
separation walls located is described, between which separation walls an
auxiliary wall has
been placed. A liquid is introduced into the two spaces thus produced. This
construction
serves for the storage of solar energy and is translucent.
A "solar boiler" is described in European application 022 389. That is to say,
two
walls a small distance apart are fitted in a roof element and the space
between them is
completely filled with liquid, such as water. Feat can then be extracted by
solar radiation.
A space remains on either side between the walls and the actual roof element.
In horticulture, but also in other building constructions, there is the
problem that on
irradiation with sunlight a rise in temperature takes place in the area
concerned. It is, of
course, possible to eliminate this rise in temperature by ventilation,
assuming that the
ambient temperature is sufficiently low. However, this produces an open
communication to
the surroundings, which under certain circumstances is not desirable.
Idloreover, it is very
well possible that the outside temperature is so high or low that active
cooling or heating,
respectively, is required.
'The aim of the present a~~vention is to provide a laartition and x~~ethod~
respecti~iel~r, by
2~ iamam of v,~hich active cooling, or alternatively laasfing, is possible
anal as a, result of v~hich
$arll~er ~ex~tilation or heating cm be dispensed v~ith. The aim of the present
in~enti~an is,
furthmxnore, to implmamnt cooling/heati2~g in s~~ch a way that there is nca or
~legligible loss
of light from any luminous radiation passing through the partition.
This aim is realised according to the invention with a partition as described
above,
wherein one of said separation walls is an external separation wall and the
other of said
separation walls is an internal separation wall, wherein said liquid film
moves over said
internal separation wall and there is a thermally insulating space between
said liquid film
and the external separation wall.
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The invention can be used both with vertically positioned partitions and with
partitions at an angle. In the case of partitions at an angle, the angle with
respect to the
horizontal is preferably at least 20°. An example of such a partition
can be found in the roof
construction for a greenhouse.
The present invention relates to a separation wall between two areas and not
to a
solar collector that can be installed independently. The thermally insulating
space
preferably comprises a space for accommodating an insulating gas, such as air.
According to a particular embodiment of the invention, in contrast to the
constructions known to date, a liquid film is fed over the internal separation
wall. However,
such a liquid film has such small dimensions that a free space or cavity that
provides
insulating properties remains between the top face of the liquid film and the
external
separation wall. That is to say, the effect of the heating of water disclosed
in European
application 022 359, which has been described above, does not arise in the
case of the
present invention because the water is not in contact with thee external
separation wall and
is even insulated with respect to that separation wall. If water or another
crystal-clear liquid
is used, in principle the light will be transmitted without substantial loss,
that is to say with
an efficiency of more than 95 °f° and more particularly with an
efficiency of more than
99 %, as a result of which negligible heating of the water caused by solar
radiation talces
place.
Eecause, however, the water flows over the internal separation wall, the
temperature
of the internal separation wall will approach the temperature of the water.
After all, if made
of plastic, such separation walls are generally made thin-walled with a wall
thickness of
less than 3 mm and in particular less than 1 mm and more particularly
approximately 0.2
a~~a2o This ~,rall thicla~ess is depe~~der~t ~n the gna.terial used and for
polycarbor~ate~ for
2~ e~~ala2ple, is approximately 0.S ~maad for T'~ is approximately '? n~~~ and
for film is
~ppro~~i~~a~ately 0.07 nn~~.
Eecause tlae vmll assumes the temperature of the cool or was~a~ vrateay
acti~ie cooling
of the area is produced. If humidity is relatively highs condensation, that is
to say
relinquishing of heat, will occur at the wall. Such formation of condensation
on the inside
of the wall can lead to water droplets that drip from the separation wall in
an undesirable
manner. This can be avoided by providing the inside of a wall with additives
or coating that
lower the surface tension. Tt is also possible to promote droplet
formation/condensation
with the aid of targeted circulation along the inside of the partition. ~ther
meaa~s to
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promote condensation that is as distributed as much as possible can be used,
such as
vibration means. Because of the presence of the "cavity" above the water layer
and below
the external separation wall, a cavity that has an insulating effect is
produced. As a result of
this insulation the absorption of heat by the building construction will be
prevented by the
presence of the cooling flow of water. Any condensation in the space inside
the building
construction will be restricted to a minimum and will always occur at the
coldest point, that
is to say at the internal separation wall.
To ensure that the water or other liquid, such as glycol, is distributed as
far as
possible over the surface of the internal separation wall, agents that lower
the surface
tension, such as types of soap, can be used. These can be present both in the
liquid
concerned and on the internal separation wall over which the water flows. It
will be
understood that said internal separation wall does not always have to be
fitted at an
inclination. This can also be vertical.
The liquid can also have a high viscosity, that is to say this is relatively
viscous.
Starting with water, this can, for example, be achieved by adding thickeners
thereto.
Between the top of the water surface and the bottom of the top or external
separation
wall there can be either air or a liquid sealing layer. This can be a
permanent further
intennediate panel completely filled with the liquid. It is also possible to
use a flexible
film, in which case the water "creeps" between the film and the top of the
internal
separation wall. The thickness of the liquid film is preferably less than 5
mm, such as 3
mm, or less than 1 mm. Such a liquid sealing layer is preferably used in
combination with a
partition positioned at an inclination. Instead of the film described above,
this can also
comprise a non-woven made of any material that floats on the liquid.
The n~echaz~i~~~~ of tlae pre-empt incyention is preferably such that the flow
rate of the
~~ liquid and tl~e temperat.~re contr~1 the quaaatit~ of heat absorbed or
released. In principle9 a
basic qa~~ntit'~ oaf liquid is always present as separator.
'fhe liquid used Ivas a preferably relati~~ely low temperatureo ~-L
ten~peratuz-e of
between 5 ~~ a~~d 1~ ~C is mentioned as an ea~ample. By this meaa~s it is
possible to absorb
and to remove a large amount of heat from the building construction. The
heated/cooled
water can, for example, be returned to a heat sink, which, for example, can be
an
underground water store. In the winter this water that has been heated to some
extent can
be used again to heat the building construction, either directly or via a heat
pump. In the
shorter terns, such as duriizg the light, it is possible to provide for
further cooling of the
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water previously used. ~ther constructions with storage vessels, heat pumps
and heat
exchangers can be envisaged by those skilled in the art and fall within the
scope of the
appended claims.
The liquid released can be discharged in any manner known in the state of the
art.
According to a particular embodiment of the present invention, a series of
nozzles is
provided along the top boundary of the panel concerned, each of which
dispenses a
distributed stream of water. It is also possible to provide for continuous
dispensing using
special dispensing hoses or tubes designed for this purpose. Moreover, the
supply and
discharge, respectively, can be integrated in a panel that forms the
partition. In particular,
the panel can be provided with a frame at the bottom and top for
discharge/supply.
According to a further variant of the invention, the external panel is
permanently
fitted in a building construction and the internal panel over which the liquid
flows is fitted
such that it can be displaced. In this context, consideration can be given to
a screen or film
layer over which the liquid moves and which can be removed as required, for
example by
rolling up. Preferably, some of the liquid is also included when rolling up,
to facilitate
realisation of the water filirl at a later stage by the liquid that is then
present between the
windings. The material of such an interxlal separation wall is preferably a
polyamide and
more particulaaly polyalnide 6.6. It must be understood that this can also be
used for the
other walls comprising the liquid sealing layer. ~ther plastic materials known
in the state
of the art, but also glass, can be used for the separation walls.
The inventi~n also relates to a method for controlling the temperature in an
area,
which area is provided with an inclined, translucent partition consisting of
transparent
separation walls at least 5 mrrl apaa-t, wherein one separation wall
constitutes the boundary
~,~ith sa,~d area, ,and the other separation vrall constitutes the boundary
~3it11 said
'~S sulxoundings, ~rherein a liquid flllm is aplalied on tlxe top of the
separati~an ~~a11 fleet
constitutes the boundary with the area, such that the top of the liquid film
is some distance
away from tlm bottom of tl2e other separation ~a~all, ~,~laerein an
insulatilag g,~s, s~~cl~l a air, is
arranged in said space, wherein the heat transpol-t to/from said area, is
determined by
controlling the amount of liquid suppliedldischarged. According to the
invention a liquid
film is, in principle, continuously present and the temperature within said
area can be
influenced by changing the flow rate, in combination with the temperature. The
insulation
with the other separation wall preferably consists of a space filled with gas,
such as arl air-
filled space.
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It has been indicated above that in principle the liquid used is crystal-
clear, that is to
say has no influence on the light transmitted. However, it is possible to
provide for
influence by means of additives in the liquid and/or coatings on the walls.
Additives that influence the wavelength of the light are mentioned as an
example. In
5 particular when cultivating plants in greenhouses it has been found that
certain parts of the
light spectrum are important and other parts are less important for growth.
Apart 'from
influencing the wavelength, it is possible to keep out certain undesirable
frequencies.
Moreover, a continuously variable control of the light transmission and/or
reflection can be
provided in that a continuous stream of water moves over the internal
separation wall of the
panel. It will also be understood that, in contrast to what has been described
above,
absorption of heat can take place by the addition of pigment and other
substances and/or
the provision of coatings.
It is also possible to influence the emergence of light from the building
construction
by introducing additives. In greenhouses, for example, screens are used at
night to restrict
the emergence of light. These could be replaced by (temporarily) introducing
additives into
the liquid. At a later stage these additives can be chemically or physically
removed in a
simple manner. In addition, it is, moreover, possible by means of these
additives to recover
the heat that is produced by lighting (assimilation lighting) by absorption.
Another
possibility at relatively high temperature is to cool down this heat using the
liquid
according to the invention.
Moreover, it is possible to introduce additives into the liquid by means of
which
chemical/physical processes are possible under the influence of radiation,
such as forms of
photosynthesis. Another example is the introduction of additives that react to
an electric
cunrea~t that as applied to the liquid film.
'~5 Instead ~f or in additioai to the additi~ie~ that inouen ce the
che~nica~physical
prolaerties of tlae liqui~l$ in the case of the use of a film layer car the
like that encapsulates
the liqu.id~ it is p~ssible to provide this fih~a layer vrith properties that
give rise to, influence
or intensify the effect of the additives that has been described above. Tn
this contempt such a
film can, for example, be fitted such that it can be displaced. That is to
say, a film may or
may not be present in the space delimited between the separation walls.
The heat transfer to the interior of the building construction can be managed
by
controlling the flow rate, the temperatuxe and the layer thickness of the
water. The layer
thiclc~mss of the liquid stream teal also be influenced by means of additives.
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Agents that restrict or stimulate thermal radiation can also be added to the
liquid.
This can, of course, also be achieved in the form of a coating on one of the
separation walls.
Eecause the water flow is supplied individually at different locations,
different
conditions can be achieved at different positions in the building
construction. Certain
advantageous situations can be achieved in this way.
According to a further advantageous embodiment of the invention, the entire
space
between the two separation walls can be temporarily filled with liquid. In
such a case a
construction similar to a solar boiler is produced by means of which heat can
be extracted.
In the case of complete filling the effect of cooling is produced at night.
The walls, and in
particular the internal separation wall, can be provided with means to improve
the heat
transfer. Examples of these are ribs, black-coloured parts and the like.
The invention will be explained in more detail below with reference to an
illustrative
embodiment shown in the drawing. In the drawing:
Fig. 1 shows, highly diagrammatically, a building construction;
1 S Fig. 2 shows, in detail, part of the roof of the construction,
Fig. 3 shows a further variant of a partition wall in cross-section, and
Fig. 4. shows another embodiment of the constx-uction according to the
invention.
In Fig. 1 a building construction such as a greenhouse is indicated by 1. The
roof or
cover is indicated by 2. As can be seen from Fig. 2, this consists of
partitions 3. Each
partition consists of an external separation wall 4 and an internal separation
wall S. With
this arrangement the external separation wall 4 is the wall that is in contact
with the
surroundings and the internal separation wall ~ is the wall that is in
conununication with
the area. The distance between the walls 4 and 5 is indicated by a and is
greater than 5 mm
aa~r~ preferably greater than 1 crr~. The v~alls can be rr~ade of glass or a
pl~.stic material of
~.~a small wall tl~icl~ness. For glass the wall thacl~~e~~ is preferablg~ less
than ~ nax~a aid for
plastic is leas than ~ r~~n~ and more particularly less than 1 nu~9 such as
0.1 lnm.
Folyc~~bon ate polymethyl nmtl~acrylate, polya~nide2 such as polyami~le ~.G~
and the like
are mention ed as e~~amples for the plastic.
At the top of the cover there is a water supply line 7 with dispensing nobbles
6. )3y
dispensing water a water layer 10 that extends over a large proportion of the
surface of the
internal separation wall 5 is produced over the latter. This water layer 10
has a relatively
small thickness9 that is to say a thickness of less than 2 mm and preferably
appro~~imately 1
nuu. In any event the thickness of the water layer that is indicated by b is
substantially less
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than the abovementioned distance a, so that a free space remains between the
top of the
water layer 10 and the external separation wall 4, which space is filled with
gas, such as air.
This space acts as insulation.
Water preferably flows over the sloping parts of the internal separation wall
5. A
wide, relatively thin water layer can be ensured by using agents that lower
the surface
tension. The effects described above in the preamble to the description can be
obtained
with the aid of this water layer. That is to say, in contrast to constructions
according to the
state of the art, no heating of the water takes place because this is in
principle crystal-clear.
Of course, other crystal-clear liquids can be used instead of water. ~y the
use of/additives
in the water, the light transmission characteristics can be influenced and
heat can optionally
be absorbed or released or the incidence/radiation of light can be influenced.
A further embodiment of the invention is shown in Fig. 3. The panel is
indicated in
its entirety by 13 and forms part of a building construction. There is an
inclined upper or
external separation wall 14 and, arranged a distance a away from the latter, a
lower or
internal separation wall 15 extending essentially parallel thereto. A liquid
film that has a
thickness b is indicated by 20. This liquid is dispensed from nozzles 17 and
flows
downwards under gravity. A layer of film 21 "floats" on the liquid. A distance
c that is
filled with gas, such as air, remains between the top of the film layer 21 and
the bottom of
the upper panel 14. The resulting space is indicated by 18 and provides
insulation. This
film can be an oriented polyamide with, for example a thickness of 25 pm.
With this construction it is possible to move a continuous Olin of water with
a
thickness of from 0.5 mm downwards. The thickness of the filin of water can be
greater if a
film layer or other encapsulating layer is used. A value of 2 - 3 mm is
mentioned as an
er~aa~ple. I~~ the embodiments shov~rn here9 tl~e top of the lower separation
~rJall is lareferably
essentially flat that is to say there are n~ ribs ~r chaamel ~t~-~ctu~e. The
flm used here9 on
its ova~n ~r iia combination with the liqui~9 ca~~ hare changing optical
properties, for
e~a~mple under the influence of an electrical voltage applied theret~.
1~'loreo~er9 it is
possible to prevent a growth of matter by means of such a voltage.
It is also possible to change the optical properties of the incident light by
means of
suitable additives to either the filin layer or the liquid. One of the
possibilities is to change
the angle of reflection such that light is no longer able to leave the
greenhouse via the
liquid and/or fih~n. l~loreover, the various aspects can be implemented in
such a way that
radiation of the infrared component of the light is counteracted.
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In Fig. 4 part of the construction according to the present invention that is
located
close to a gutter is shown as an alternative. It will be understood that the
same construction
can be incorporated in any other location in a building construction, such as
at a girder
where there is a frame for collecting liquid, which optionally is integrated
in a housing,
which contains the roll-up section as to be described for Fig. 4. This gutter
is indicated by
25. The external separation walls are indicated by 26 and 27, respectively.
There is a
window 28 that can be swung open in one external separation wall 26. The
operation of
this window can be effected by means of any construction known in the state of
the art.
According to a particular embodiment according to the invention, with this
arrangement
use is made of a scissor-like construction that is located in the plane of the
external
separation wall 26, as a result of which the liquid stream remains unimpeded.
The internal
separation wall is indicated by 30 and 31, respectively. The liquid flows over
this. There is
a roller construction 32 by means of which the internal separation wall can be
rolled up,
that is to say can be removed. Preferably, rolling up takes place in a
situation in which the
internal separation wall is damp, so that subsequent unrolling is facilitated.
After the
internal separation wall has been rolled up, this will not constitute any
impediment to the
light passing through.
The gutter 25 is a special construction. This contains an upper channel 32 for
removing rainwater. For this purpose there is an opening 33 in cover 34.
Furthem~ore, there
are channels 35 that, via the openings 36, collect and remove the liquid
originating from
the liquid film that is moving over the internal separation wall. This takes
place separately
on the left and the right. There is a further channel 37 for the condensation
collecting on the
inside of the internal separation wall 30, 31. A fixing for the internal
separation wall 31
that ca~~ lae rolled up is indicated by 33. That is to ~a~- the roller 32
na~a~res tov,~ar~s tla_e
firing 3~ vrhen r~lling up at~d ava%ay from the fagging 33 ~~heu unrollinge
hr the examples described alao~e the water nm~res over the ig~terr~a.l
separation vrall of
the lam-titi~a~~. ~~~~,rc~~er~ it is als~ possible to m~~re the liq~~id over
the e~cteraml ex,~al1 that is to
say over wall 27 in Fig. 4..
In the embodiment according to Fig. 4, it will still be possible to move a
liquid film
over internal separation wall 30 when the window 28 is opened. This liquid
enters into
interaction with the surroundings when window 2~ is opened.
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In the embodiment shown here, where the water moves over the internal
separation
wall, the external separation wall can be provided with a coating that
counteracts
condensation in order thus to influence the translucency as little as
possible.
As a result of the use of plastic panels, a relatively small wall thickness
can suffice,
as indicated above. Because plastic can be made more translucent than glass
and as a result
of the smaller wall thickness thereof, a particularly high light transmission
can be obtained
in combination with a crystal-clear liquid. Moreover, the weight of the
construction can be
limited appreciably compared with constructions that are made up of double
glazing.
However, the use of glass is still a practical option.
The water or other liquid is preferably fed from the nozzles 6 at a relatively
low
temperature if it is desired to cool the interior of the building
construction. A temperature
of 5 - 12 °C is mentioned as an example if the aim is for a rise in
temperature of the liquid
film 10 of more than 20 and preferably approximately 30 - 40 °C. The
temperature of the
water must not be so low that fieezing can occur.
By temporarily filling the space between the walls 4 and 5, a conventional
solar
boiler or cooling construction can be provided.
Although the invention has been described above with reference to a preferred
embodiment, it will be understood by those skilled in the art that numerous
modifications
can be made thereto without going beyond the scope of the present application
as described
in appended claims.
