Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present inventi.on relates -to an arranyemen-t
in windows Eor bringiny -the surface oE an innermost window-
pane to a suitable -tempera-ture Erom a comfort aspect, said
window-pane toyether with a further window-pane being
arranged -to deflne a substan-tially closed space.
The comfort cri-terion of a hea-ted room is the so-
called directive operative -te:mperature. The value of this
temperature is determined by the radiation climate and the
air temperature at selec-ted reference points in the room.
; 10 The radiation climate is a:Efec-ted negatively by room surfaces
which are cold due to transmission losses, especially windows,
since such surfaces obtain temperatures whicll are lower than
the desired room tempera-ture. ~y means of an arranyement
of one or more hermetically sealed spaces between panes of
ylass, i.e. one or more so-called ~hermo-glass* panes, which
.. are available under the trade mark "Thermopane", it has
been possible to sliyhtly raise the temperature of -the inner
window-pane as compared -to conventional, coupled double-
ylazed windows. The temperature of the inner window-pane,
however, will be relatively low and the pane will have a
cooling effect, if only such passive measures are taken.
A better result is obtained when the space be-tween
the innermost panes is flushed wi-th warm air, suitably sup-
ply air or exhaust air. Because of the heat los-t to the
external surroundings, it is necesary for the air to flow
at a high rate, so that the temperature of the flowiny air,
and therewith also the temperature of the innermost window-
pane, does not fail beneath room tempera-ture on the outlet
side. The heat losses and the difficul-ties of achieving
requisite flow rates in -the confined space available in a
window s-tructure, which window must also be capable of being
opened and has coupled frames to enable the surEaces of -the
glass contacted by the air to be cleaned, have meant that
solu-tions of this kind are no-t totally realistic.
It is highly desirable to find a solution to the
problem of maintaining the inner window-pane at a sufficien-tly
high temperature, since tests have shown tha-t -the room tem-
perature can be lowered one or two degrees while maintaining
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a com.Eor-table climate, iE the radiation of cold from the
wlndow can be totally ellminated, by bringing the tempera
ture of the inner window-pane to the same temperature as
the room, or sliyh-tly higher. In this la-tter case, -the cold-
generatiny inner window-pane has become a heat emitter. 'rhis
enables other heat-emit-ters in the room to be reduced in
number, or to be totally omitted.
According to the present invention, there is
provided a window arrangement comprising a window frame, an
innermost window-panc and a further window pane dLsposed in
the frame and spaced apart from each other, an in-termediate
window-pane disposed between the innermost window-pane and
the fur-ther window-pane so as to deine an inner cavity
between the innermos-t window-pane and -the intermediate
window-pane and an outer cavity between the intermediate
window pane and the further w:indow~pane, a passageway
disposed in one end of the frame and affordiny communica-tion
between the inner and outer cavities,..an inlet opening
disposed in -the other end of the frame and communicating
with -the inner cavity and an ou-tlet opening disposed in the
other end of the frame and communica-ting wi-th the outer
cavity, means Eor causing warm air to flow through the
inlet opening into the inner cavity and thence by way o~ the
passageway into the outer cavity finally exitiny through the
outlet opening, and means for controlling -the temperature
and rate of flow of the warm air such that, in use oE the
window arrangemen-t, the warm air entering the inle-t opening
i5 at mos-t a few degrees above the temperature of room air
on the inside oE the window arrangement and tha-t air exiting
30 the inner cavity is at a temperature substantially equal
-to the temperature of the room air.
~ he tempera-ture curve followed by the air circula-
ting around the intermediate window-paner the surface
temperature of the inner window pane and the total trans-
mission loss are determined by a number of different para-
meters. ~mong these parameters can be mentioned the original
K-value of the window, the internal radiation charac-teristics
of the double cavity, the resistance to thermal transmission,
air
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replacement, and the :Lnle-t tempera-ture of the air. ~y pass-
ing the aix (either in total or in part) through the air
gap lyiny neares-t the innermos-t cavity, subsequen-t to said
air having passed the innermost air gap, the pane lying
between the two cavities is he:Ld at a higher temperature
than is -the case when air is passed solely through the inner-
most cavity Sin the case of a single cavity). This means
that when the air passes through the innermost cavity, said
air is not cooled as greatly as i-t would be in -the case of
a single cavity. Conse~uentl~ the air flow can be lowered,
or alternatively the inlet temperature can be lowered, while
still maint~ininy the temperature of the innermos-t pane at
the same level as in the single-cavity case.
At an external temperature of, for example, -20C and
a desired room temperature oE, Eor example 20C, the tempera-
ture of the air at the inlet to the substantially closed
space need only be abou-t 23C, to fall to about 20C subse-
quent to passing -the inside of the intermediate pane. Sub-
sequent to passing the outside of the intermediate pane,
i.e. at the outlet of the space, the air temperature will
have fallen to about 11C. In order to re-heat the air to
23C, ~or example by means of hot water, in an effective
heat exchanger, the temperature of the water entering the
heat exchanger need, ideally, only be in the region of 23.5
C~ the temperature of the water exiting from -the heat ex-
changer being, ideally, for example 11.5C, i.e. the tempera-
ture of the return water lies far beneath the room tempera-
ture, despite the fact that the whole of the inner pane has
been brought to a temperature which does not lie beneath
the room temperature of 20C.
As will readil~ be understood, this provides unsuspec-
ted possibilities of utilizing low-grade energy, such as
low-temperature waste heat, solar energy, heat ~rom storage
batteries etc. A solar-energy collector, which~may operate'
with an inlet temperature or outlet temperature o~ the cir-
culating heat carrler o~ only 11-15C or 23-27C respective-
ly obtain a much higher efficiency than is normally usual.
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When the arrancJement according to the inventlon is
used in a build.ing havlng low K-values in the walls, and
optionally a hea-t-e~changer for the inpu-t./output-air of the
building, it is -thought that in many cases no fur-ther heat-
emi-tting apparatus would be required or hea-ting -the build-
ing, in addition to the aforementioned approximately 23-
27/11-15C-water system. Wi-th a -temperature differential
between the ingoing and outgoing circulation-water of about
12C, an equally large water flow can be used as i5 normal
practice in existing buildings. Thus, when renovating such
buildings, the arran~emen-t accordillg -to the inven-tion can
be connected directly to the pipelines of the existing heat-
ing system, with or without existing radiators.
The :Lnvention will now be described in more detail
with reference to a number of embodiments of arrangements
according to -the invention illustrated schematically :Ln the
accompanying drawings, in which
Figure 1 is a cross-sectional view of a window with
a heat-exchanger incorporated ~n the window frame,
Figure 2 is a cross-sectional view oE a window with
the heat-exchanger and a fan incorporated in a window sill,
Figure 3 is a cross-sectional view of a window which
is provided with two substantially sealed spaces and which
is connected to a warm-air line arld a return line, the re-
turn line being connected to a heating plant, and
Figure 4 is a diagram illustrating ~he temperature
conditions in, for example, the embodiment illustrated in
Figure 1.
In Figure 1 there is shown an outer wall 1 having a
window opening 2, in which a window frame 3 is fitted. Hung
in the window frame 3 is an outer casement 4 having a conven-
tional Thermopane* 5 compr.ising two panes of glass. Inwardly
hereof are arranged two further casements 6, 7, of which
the casement 6 carries a Thermopane 8, comprising two glass
panes, such as to form a cavity 9 between the Thermopanes
5 and 8, and so as to form a cavity 10 between said Thermo-
: pane 8 and an inner pane 11 fitted to the casement 7.
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Be-tween -the upper parts of the casements ~ and 6 and
-the casemen-t~ 6 and 7 are arranged deep slots 12, while chan
nels 13 which connect the slo-ts 12 are arranged in -the upper
part of the casement 6, immedia-tely above the upper edge
S ~f the Thermopane ~.
Arranged between the casements 4, 6 and 7 ~re through-
passing slots 14, which terminate in corresponding slots
15, 16 i.n the lower part of the frame 3, in which frame there
is also arranged a chamher 17 which connects the slots 15,
16 along practically the whole wid-th of the wi.ndow. Arrang~
ecl in the chamber 17 is an elongate, hiyhly ef:Eective counter-
flow heat-exchanger 18, having transversely extending, fine
passages which connect the sl.ots 15, 16, and optionally a
fan means 19, which directs a relatively slow air flow up
into the cavity 10, while drawing air from the cavity 9 via
the heat-exchanger 18. The heat-exchanger 18 is provided,
in a conventional manner, with a tube-coil 20, -the ends of
which are connected to a hot-water line 21 and to a return
line 22 respectively.
The air heated in the heat-exchanger 1~ flows slowly
upwards through the slot lS, and into the cavity 10, option
: ally with the back-up of :Ean 19. As the warm air leaves
the cavity 10 it passes through the slots 12 and the pass-
ages 13 in the upper part of the window, and then flows down
through the cavity g while being cooled so~newhat by the re-
:~ latively cold panes 5. The cooled air is drawn down through
the slot 16 and passes through the heat-exchanger 18, where
it is re-heated.
As previously described, and as will be made more clear
~ 30 hereinafter with reerence to Figure 4, the inner window-
: pane 11 can be brought to a surface temperature which is
almost egual to the intended xoom temperature of r for ex-
ample, 20gC over the whole of the surface of said pane, while
using a water temperature of 23-27C in the input line, and
.: 35 a water temperature as low as 11-15C in the return line.
The embodiment illustrated in Figure 2 differs from
the Figure 1 embodiment, in that a single window-pane 25
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i9 used instead of the ~hermopane 8 in Figure 1, and in that
the heat-exchanger 18 has been moved out and placed in a
chamber 26 located in a window sill 27.
~ he embodiment illustrat~ed in Fiyure 3 has a further
double-cavity 31, 32 defined by two Eurther window-panes
29, 30 and formed in the same manner as the cavities 9, 10.
Slots and passages in casements and window frame are so
arranged and so connected to a hot-air passage 33 and a re-
turn passaye 34 that warm air will rise up through the inner-
most cavity 10, down through the cavity 9, through the cavi-
ty 31, and down through the outermos-t cavi-ty 32. As will
be understood, the ternperature difference in this case is
still greater than the diEEerence of approxima-tely 12C
assumed in the previously described embodiments.
Figure 4 illustrates the temperature distribution from
the outer window-pane 5 to the inner window-pane 11 and in
the two air cavities 9 and 10 along the whole height (m)
of the window. The outside temperature is assumed to be
-20C (T) and the inside temperature ~20C. The temperature
of the air when flowing in to the cavity 10 is 23C, and
when exiting from the cavity 9 is only 11C. Despite this
low temperature of the inflowing airt the surface tempera-
ture of the bottom part of the inner window-pane will be
21.2C and at the upper part of said pane 19.7~C, i.e. tem-
peratures practically e~ual to the inside temperature.
With a window of this kind, so-called cold slide will
not occur, and the window will not be considered as a cold
surface. When the surface temperature is raised through
about 1C, the window may also be considered as a warm sur-
face, and if such windows are arranged in a low-energy build-
ing, additional heat-emitting devices may be more or less
superfluous
In the event of powerful solar radiation, for example
in the summertime, the watex temperature may, of course,
be lowered somewhat, in which case the window arrangement
according to the invention can alternately be used to keep
the room cool.
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In order to prevent condensation, the cavitie~ are
ventilated to ambient air through a fine passage/ in a con-
ventional rnanner.
As will be understoodl the fan and heat-exchanger need
not be placed adjacent one another and, if so desired, the
ian may be incorporated~ for example, in the upper part of
the window Erame.
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