CA1215588A - Arrangement in windows - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A window arrangement is disclosed by means of which an innermost window-pane is brought to a surface temperature suitable from a comfort aspect, the innermost window-pane and a further window-pane being arranged in a window frame to define a generally closed space. The novel features of the invention include means for causing the air in the afore-mentioned space to flow from an inlet to an outlet around an intermediate window-pane arranged in the space with means provided for warming the air prior to entering the cavity between the innermost window-pane and the intermediate window-pane.

Description

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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 *trademark ---~
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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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~SS~38 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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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A window arrangement comprising:
a window frame;
an innermost window-pane and a further window-pane disposed in said frame and spaced apart from each other;
an intermediate window-pane disposed between said innermost window-pane and said further window-pane so as to define an inner cavity between the innermost window-pane and the intermediate window-pane and an outer cavity between the intermediate window-pane and the further window pane;
a passageway disposed in one end of said frame and affording communication between said inner and outer cavities;
an inlet opening disposed in the other end of said frame and communicating with said inner cavity and an outlet opening disposed in said other end of said frame and communicating with said outer cavity;
means for causing warm air to flow through said inlet opening into said inner cavity and thence by way of said passageway into said outer cavity finally exiting through said outlet opening;
and means for controlling the temperature and rate of flow of said warm air such that, in use of the window arrangement, the warm air entering said inlet opening is at most a few degrees above the temperature of room air on the inside of the window arrangement and that air exiting the.
inner cavity is at a temperature substantially equal to the temperature of said room air.

2. An arrangement according to claim 1, wherein said passageway and said inlet and outlet openings extend over substantially the whole width of the window-panes.

3. An arrangement according to claim 1, wherein the means for causing air flow into and. through said cavities comprises a fan which is active over the whole width of the window-panes.

4. An arrangement according to Claim 1, 2 or 3, wherein a counter-flow heat-exchanger is incorporated beneath a window sill forming part of the window-frame.

5. An arrangement according to Claim 1, 2 or 3, wherein the intermediate window-pane comprises a pane having good heat insulating properties.

6. An arrangement according to Claim 1, 2 or 3, and including two further, outwardly lying cavities separated by a further intermediate window-pane around which air is arranged to flow from said outer cavity.