Title:
Window device
Technical field:
The present invention relates to a window device with a pane arranged to delimit the radiation from one side to a larger extent than from the other side, whereby the pane is intended to be turned into different positions dependent of the seasonal variations of the intensity of solar-radiation.
With windows there are two problems, that are related to the energy transmission through the pane. One of these problems is how to obtain a high thermal insulation when the outer temperature is so low that heating is required indoors in order to uphold the chosen room temperature. It is thereby known to give the window an improved quality of thermal insulation by providing it with a plurality of panes placed after each other, so that interspaced air or gas, trapped between the panes, being a relatively poor thermal conductor, operates as insulation, so that transmission through conduction is reduced at the same time that the relatively small gaps between the panes counteract thermal transmission by convection.
However, these mechanisms of insulation does not constitute the object of the invention, even if said arrangement can be used together with the window according the invention. Instead, the invention is orientated towards thermal transmission through radiation. Here, it is known to provide the window pane with a so called low emission film, a thin, transparent metal-layer, decreasing the thermal radiation from the inside of the window to the colder surrounding. Thus it is known to use such low emission films on window panes in order to decrease the thermal transport.
The other problem is that when direct sunlight or strong reflected radiation is radiated in through the pane, one obtains too strong indoor heating. It is known to decrease this radiation by so called heat-absorbing glass-panes, consisting of a glass compound into which is mixed a thermal-radiation absorbing substance such as a metal oxide. A glass-pane of this kind decreases the direct radiation and thereby the unwanted heating inside the pane.
In areas with a need for heating during a large extent of the year, the first kind of windows are normally used, which thus are set for insulation against heat leakage. In areas with little or no need for heating, but with strong radiation, the latter kind of windows are used, which thus are to decrease heating by radiation. In this case one can of course also use multiple-layer panes, but this would then be intended to decrease heat transmission from the outside to rooms cooled by air-conditioning.
In areas with a cold and a warm season, one often choose the first kind of windows with the intent of decreasing heating costs. This causes difficulties during the summer season because of strong solar radiation. This situation has been further accentuated by increased window sizes, sometimes to entire glass facades, and by the fact that the number of office machines has increased in today's office environment, resulting in increasing room heating.
Background:
A window device would therefore be desirable, which could be adapted in such a way, that it provided high thermal insulation, when the outer temperature makes this desirable, and that the sunlight is made use of for room heating, the window being at the same time usuable for sun-deflection during the warmer season.
It has also proved possible, to combine both said effects by way of a window-pane having a rectifying or diode-effect on the radiattion. On radiation from one side it will delimit this radiation and thus work as an insulation against thermal radiation, whilst it to a considerably larger extent lets through radiation from the other side. If such a pane is placed with the first side inwards and the other side outwards in a building, it will have the effect of an insulating pane suitable for use at a low outer temperature. The radiation from the inside of the heated building is thus inhibited whilst solar radiation from the outside during sunny days, is let through. If, on the other hand, the pane is turned completely around, so that the diode-effect will work in the opposite direction, the pane will work as an insulation against solar radiation from the outside.
In this position, the pane is thus suited for use during that part of the year, when the outdoor temperature is relatively high and the solar radiation is strong.
Of this kind of windows, one is known from US-A-4 235 048, which is suggested to be turnable. It consists of a pane comprising a transparent under-layer, one side of which has a reflecting film covered with an absorbing film, in its turn finally covered with an antireflecting material. Furthermore, US-A-4 180 954 shows a pane of glass, covered with double layers, that is an absorbing layer closest to the surface of the pane, covered with a reflecting layer. The pane is suggested to be a part of a turnable window with multiple panes.
Technical problem:
The known technique thus discloses windows having a diode-effect, which windows are suggested to be turnable between a winter and a summer position. It has thereby been suggested that the diodeeffect can be achieved by a pane covered with a plurality of layers. Such-layer covering is a process demanding great accuracy and large investments in manufacturing equipment.
The solution:
The pane according to the invention comprises a supporting base layer of a material being radiation-absorbing and transparent, such as glass, which encloses particles delimiting the transmission of radiation through the material. At one side of said layer, there is a layer composed of a film of the type having a low thermal emission, such as a metal film letting through radiation.
This composition of layers provides for a larger ability to inhibit the transmission of radiation from that side, on which the first-mentioned, absorbing layer is positioned, than when the radiation comes from the opposite side, where the low emission layer is positioned.
Advantages:
By the invention is provided a pane, able to create a diodeeffect in a window, preferably a turnable window, in which pane the effect is achieved by the covering with one single layer, which considerably simplifies manufacture and makes possible a lower manufacturing cost.
Brief description of drawings:
In the following, an embodiment of the invention is described by example only and with reference to the accompanying drawings.
In the drawings, figure 1 diagrammatically shows a cross-section through an insulating window with two panes and an interstitial interspace, the window being positioned in a summer position;
Figure 2 shows the window in the same manner as positioned in a winter position; In figure 3 the window is shown in a crosssection together with sash, jamb and mountings, intended to facilitate the turning of the window, and in figure 4 along with figure 5 a diagram is shown over the energy efficiency of a window according to the invention.
Best mode of carrying out the invention:
According to figure 1 and 2 an insulating window 1 comprises a first pane 2 of clear glass, which hereinafter will be-referred to as the clear glass-pane, and a second pane 3 having diodeeffect, hereinafter referred to as the diode-pane. In a customary way both panes are joined together with a frame 4, leaving an interspace 5 between the panes in which a layer of gas is hermetically enclosed. The unit consisting of the panes 2 and 3 and the frame 4 is in its turn mounted in a window-sash 6.
A clear glass-pane 2 will not be further described here, as it can consist of clear glass of a conventional type. However, the device according to the invention does not exclude that the pane 2 may be of another type; it can for instance be provided with a thin metal layer of a low-emission type.
The device according to the invention more specifically relates to the diode-pane 3. This pane consists of a supporting layer 7 of a transparent material, preferably glass. The supporting part 7 of the pane has a thickness in the range of 3-6 mm depending on the size of the pane as well as its application. The material in the supporting layer 7 of the pane is absorbant in the near-infrared range. Data concerning the material will be given in the examples hereinafter.
On the supporting layer 7 of the pane 3 there is a layer 8 in the form of a thin film. This layer is reflecting and is thus of a low-emission type. This quality can be achieved by using a layer that consists of a metal layer, being so thin that it is transparent. As will be seen from figure 1 and 2, the layer 8 is faced inwards towards the hermetically enclosed space 5 and is thus protected from direct touch. More specific data concerning the layer will be given in the examples hereinafter.
In figure 1 and 2 it is assumed that the window, which is presumed to be placed in the outer-wall of a building, has the interior of the building on the right hand side in the figures and the outer surrounding on the left hand side. Accordingly, figure 1 shows the position, into which the window will be turned during the summer season. In this position the incoming solar-radiation from the outside is absorbed by the solar-absorbing glass of the layer 7. The glass is hereby heated. The low-emission layer 8, being applied on the inside of the layer 7 towards the space 5, now prevents re-emission of the absorbed solar radiation to the right in figure 1 (in a direction towards the room).
Thus one obtains a re-emission of the absorbed solar-radiation directed towards the outside. Furthermore, there is a thermalinsulating effect caused by the gas i the gap 5. The interior of the building is thus insulated from too strong a heating by incoming radiation and the need for air-conditioning or other cooling can be eliminated or decreased.
During the winter season, on the other hand, the window is turned in the way shown in figure 2. Hereby the solar-radiation from the outside (from the left) will first hit the low-emission layer 8 without passing through the supporting, absorbing layer 7, but after passing the clear-glass window 2 and the gas-gap 5. A certain amount of the thermal radiation from the inside is re-emitted in the surface of the layer 7. The part of the solar-radiation from the outside that is aborbed in the layer 7 is re-emitted into the building.
In the described winter position the outward bound thermal radiation is affected to a high extent, so that a good insulation is achieved, whilst the inward bound thermal radiation is affected to a lesser extent, whereby the heating from the sunlight can be made use of, when such radiation exists in the wintertime. Hereby, one obtains a heat-increase in the room by the absorbed solar-radiation in the window.
In figure 3 is shown an example of how the described window 1 can be mounted. The window 1, thus consists of the panes 2 and 3 with the frame 4, and the sash 6, can also be seen in figure 3. This window-sash shall fit into a jamb 10, in which a rebate 11 is taken up for the window 1. The window is presumed to be rectangular and the sash 6 has a first horizontal edge 12 and a second horizontal edge 13 along with hereto perpendicular, vertical side-edges, which are parallel to the plane of the paper in figure 3. At each one of these side-edges is pivotably mounted a stay 15 by way of pins 16. The stays 15 reach out to pivotingpins 17 at the top end of the rebate. Along the side-edges of the rebate, of which one is shown i figure 3, runs a track 18.
In each one of these tracks there is a movably arranged runner 19. The runners 19 are pivotably mounted with one mounting 20 each at the side-edges of the sash 6 by the top edge 12.
If the window is turned anti-clockwise from the half-open position in figure 3, the runner 19 will be moved in the track 18 to its top end during pivoting of the two stays 15 until the sash settles inside the rebate 11, whereby side-space has been saved for the stays 15. If, on the other hand, the sash is pivoted clockwise, the runner 19 will follow the track 18 to its lower edge and the sash settles in an opposite position in the rebate 11 compared to what happens when the window is pivoted anticlockwise. The window can thus be put into operating positions in the rebate 11 with either the first or the other side facing outwards. This makes possible such a turning of the window between a summer- and a winter position as described in connection with figures 1 and 2.
The summer position (figure 1) is thereby obtained by the described anti-clockwise turning and the winter position (figure 2) by the clockwise turning according to figure 3.
Example 1
The diode-pane 3 has the following embodiment:
The supporting layer 7: Glass of the plane-glass type in which the glass-compund is added with solar-absorbing particles, preferably metal-oxide particles. The particles can exist in such a tightness, that the aborption ability regarding penetrating solar radiation (a in figure 4, 5) is preferably between 10 and 80 %.
The layer 8. A film of thermal low-emission type, a metal comprising layer with a thickness not below 500 Angstrom. The layer can consist of a metal-oxide or a metal for instance applied by steaming. The thermal reflectance shall be in the range of 50 to near 100 t. Concerning the thermal radiation the reflectance for achieving a good effect should be high and can in this regard be 100 t. It is however practically difficult to reach this level without reducing the transmission in the visible spectrum to an unacceptable extent.
The result
For the heat-transport in a window with two panes, model calculations have been carried out regarding summer- and winter circumstances. The heat-transport is hereby compared in correctly and incorrectly turned windows according to the circumstances in question. The correctly turned summer-position is thereby the position shown in figure 1 (corresponding to the line with reference A in figure 4, 5) and the incorrectly turned summer-position is the position shown in figure 2 (line B) and incorrectly turned in figure 1 (line A).
From calculations carried out with the heat-balance equation one gets a heat-transport during summer circumstances, which is graphically shown in figure 4. Hereby is shown two fully drawn curves designated A for the heat-transport in the correctly turned position (according to figure 1) and with dashed curves designated B for the incorrect position (according to figure 2). The upper pair of curves thereby relates to a higher intensity of radiation: 500 Wm2 and the lower pair of curves: 100 Wm'2 This is thus the outer heat-flow. The inner heat-flow is indicated on the y-axis.
It is dependent of the solar-absorptance a which in turn is dependant of the embodiment of the absorbing pane 7; the amount of particles in the same. a is thereby the proportional value for radiation penetration: a = 0, no radiation effection a = 1, total blackout.
The curves clearly indicates how the desired decrease of the inner heat-flow to a high extent is achieved with the window in the correctly turned position, whilst affection is small with the window in the incorrectly turned position.
Figure 5 shows winter-circumstances. Here, one desires little affection of the inner heat-flow in relation to the outer. This is also obtained at different levels of absorptance a with a correctly turned pane, position B, fully drawn line (thus according to figure 2). When using an incorrectly turned pane, on the other hand, position A, dashed line, one obtains high affection on the inner heat-flow, thus a small let-through of solar-radiation, which in this case is undesirable.
The calculations and the curves representing them thus clearly shows that the desired effects are achieved by the invention.