DE2619793A1 - Greenhouse with shade and temp. control - has panes partially covered and sliding panels for remainder of area (NL181176) - Google Patents

Abstract

A greenhouse has a sloping roof with a large number of panes of glass, some of which carry reflective sheets and others which have reflective sheets over half their area so that the brightness and heating effect inside is reduced. The half sheets may be controlled by a drive so that they can be moved to cover the remainder of the uncovered area of the panes. They may be aluminium strips attached to the inside of the panes or may be movable sheets mounted underneath, to travel on runners. In another form, the panels may increase the heat of the sun passing through. In the first form, they may also act as heat insulation. The fixed sheets may occupy about half of the total glazed area.

Description

DipJ.-lng. Ludewig Dipl.-Phys. Montzel

Patentsw J ta
56 Wuppertal-Barmen

Unterdörnen 114 Tel. 553611/12

April 28, 19 76 RS / kh

GEBR. GYSI AG, CH- 6340 Baar (Switzerland)

Shading device on a greenhouse

The invention relates to a shading device on a greenhouse.

It is known to use shading devices in greenhouses in order, on the one hand, to increase the temperature in summer and on the other hand to achieve better crop yields. In particular, obligatory shade plants do not tolerate any high light intensities and thrive better in shaded greenhouses.

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It has been shown that fully permanent shading systems, e.g. B. applying shading paint to the entire roof area, are disadvantageous compared to mobile shading devices. The disadvantage is permanent shadow that in cloudy weather the light intensity in the greenhouse is too low. Furthermore, through the shading medium the spectral quality of the light can be influenced, which also leads to growth depressions in the plants can.

Blinds or cover foils, for example, are known as mobile shading devices, but their temporary attachment is labor-intensive and has no thermal insulation properties whatsoever. The huge increase in heating costs in horticulture has led to new considerations in this regard and aroused the desire for a shading device which also serves as thermal insulation in the greenhouse.

Otherwise, today's fuel prices could force the gardener to To leave conventional greenhouses and to move to isolated culture rooms with a smaller proportion of glass.

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INSPECTED

The invention has set itself the task of a shading device to create in which the disadvantages of known devices are avoided and their use a saving in heating costs in the operation of the greenhouse. In addition, newer knowledge about the need for light and the Light intensities are taken into account during plant growth.

According to the invention, this is achieved in such a way that the device consists of light and heat rays reflecting elements, which on the underside of the roof surface and / or in the same are arranged, and that at least some of these elements are stationary and attached at a distance from one another by at least to cause permanent partial shading of the interior.

The considerations that led to this solution went assume that permanent partial shading is cheaper than temporary shading. Through a reflective Shading is also achieved that the quality of light, expressed in the spectral composition of the light, is not is greatly changed and influenced and, even in cloudy weather, the plants can still be cultivated properly in the greenhouse allowed. Compared to known measures to design the interior shading as thermal insulation, the reflection the thermal radiation achieves higher heating cost savings.

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In an advantageous embodiment of the greenhouse aluminum foil is laid in strips or in a checkerboard pattern on the underside of the roof surface, creating a high Scattering of light and heat radiation is achieved.

Depending on the position of the sun, the plants are periodically in front of direct through the wandering, strip-shaped shadows Protected from exposure to light. These "recovery phases", during which only the reflected light affects the plants, are conducive to plant growth.

In the case of light-sensitive cultures, it would be desirable to change the shading also to change as a function of the radiation intensity and the outside temperature, as it has been shown that in the case of the fixedly arranged elements, the duration of the direct irradiation with an approximately vertical position of the sun can get too big.

In an advantageous embodiment of the invention the shading device is therefore supplemented in such a way that the remaining elements produce full shading between a first one Position and a second, the partial shading causing position are movably arranged, and that means for displacement these elements are provided between their two layers.

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Exemplary embodiments are described below with reference to the drawings the invention explained in more detail. Show it:

Fig. 1 is a view of a greenhouse from the front,

FIG. 2 shows a side view of the greenhouse according to FIG. 1, whereby on the left side an execution of the shading with foils is shown and the right side for illustration with solar collector elements arranged in the longitudinal direction is provided

FIG. 3 is a top view of the greenhouse according to FIG. 1, and

4 shows the greenhouse according to FIG. 1 in section.

The greenhouse shown in the figures consists of a known Way from a framework 1, which is anchored in a foundation 2 and to which glass panes 3 and a door 7 are attached are.

Ventilation blades 4 arranged in the ridge 8 serve to ventilate the greenhouse,

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Strips of aluminum foils 5a are located under the roof surface Fixed installed, which reduces the incidence of light. Instead of laying them in strips, the aluminum foils could be used also be laid out like a chessboard or in some other way. The width of the foils can be around 50-100 cm.

The film is expediently creased in order to achieve the greatest possible scattering of the light and heat radiation. The reduction in brightness in the greenhouse compared to outdoor brightness is around 65% with diffuse light. It is assumed that around 50 % of the roof area is covered. An air layer can be provided between the film and the glass, which aims to provide good thermal insulation.

Instead of covering individual panes of glass on the roof with aluminum foil, It is also possible to use reflective, heat-insulating panels instead of the glass panes in the roof to use. These plates are expediently designed as solar collector elements 6a, which further save energy enable.

In addition to the stationary shading 5a, 6a, a mobile shading 5b, 6b can now be provided, which is in function the radiation intensity and the outside temperature is adjustable.

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The mobile shading 5b consists of rectangular frames covered with aluminum foil, which are on the underside of the roof are displaceable in the longitudinal direction of the greenhouse. The frames run on rails 9 and are not shown in detail Way driven by a motor through a shaft and a rack.

The size of the frames and their mutual spacing correspond the formation of the stationary film strips 5a in such a way that the mobile shading 5b is in a first end position can be pushed completely under the stationary shade 5a.

The mobile shading can be regulated automatically by a control device. The control unit can have a brightness sensor which can be set to a low and a high light intensity setpoint. With light intensities, which are below the lower setpoint, the mobile Shading automatically moved to its first end position. In the case of very intense irradiation above the upper target value the mobile shading is moved towards its second end position, achieving complete coverage of the greenhouse will.

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In the second end position, when the greenhouse is completely shaded, the light only penetrates from the side. It it has been shown that such phases of relaxation and rest especially during lunchtime when there is intense radiation, which are conducive to plant growth.

If the light intensity is between the two target values, the mobile shading is cycled through the control unit is fully open and fully closed, with the opening interval per cycle proportional to the measured light intensity is.

In the light-sensitive plants of the lower setpoint to 5 ¹ OOO Lux and the 'upper setpoint to 15,000 lux, for example, set at the control device. If the brightness meter z. B. a momentary irradiation of 10 ¹ 000 Lux measured, and the cycle time is set to 20 minutes, the mobile shading is kept fully open by the control unit for 10 minutes and kept fully closed for 10 minutes according to the measured 50% intense radiation intensity.

Although shorter cycle times than 20 minutes would be cheaper, this interval should not be significantly undercut, taking into account the wear and tear

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The setpoints to be set on the brightness meter must be determined empirically. With less' sensitive plants z. B. values of 10'0OO Lux or 20 ¹ OOO Lux proven.

In another embodiment, there is mobile shading 6b from below reflecting plates 10, the size and arrangement of which corresponds to the collector elements 6a. The plates, which are covered in their first end position by the elements 10, can by pulling cables 11 against their second, a complete Covering the greenhouse causing the end position to be pulled.

The full coverage of the greenhouse during the night brings with it considerable energy savings, on the one hand the heat rays are reflected and, on the other hand, a high insulating effect due to the air layer between the film and glass is achieved. When using plates, these are expediently made of heat-insulating material.

Before carrying out the above-described shading device, the difficult question was asked about that required by plants Discuss minimum amount of light for healthy growth. This in particular also with regard to permanent partial shading, which must not impair growth even with low outdoor light intensities in winter.

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According to the classical understanding of the theory of plants about the light needs of plants, these require maximum light intensities. But if one interprets the experiments of the last few years and takes into account the fact that the Plant leaves only about 1-21 of the incident light is photosynthetically bound, one can come to the conclusion that lower light intensities are also permissible. Special the experiments with strong and weak flashes of light, which led to the same assimilation rates, and the resulting derived assumption that in the first light reaction only every 500th chlorophy! molecule is active, also show in this direction. They liked the solution with the aluminum foil laid in strips or in a checkerboard pattern guided on the underside of the roof surface.

Experiments with plants that require light, such as poinsettia and geraniums, have shown normal or very good growth in the months with very little light. It is essential that the panes that are not covered are absolutely clean and do not cause selective absorption or reflection. Due to the very low emission number of aluminum (0.049), almost all heat rays are reflected on the film and radiated back into the greenhouse space. In addition, the air layer between the film and glass achieves a high insulating effect. The heat savings were shown in tests to be 40-50 % .

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In greenhouses without mobile shading, the uncovered panes remain unshaded. Here the fact is exploited that the light wanders constantly, and the shadow strips from the covered panes direct the plants in front of them Protect radiation completely. The plants can recover in full shade and so survive the short-term, full one Irradiation.

In greenhouses with additional, mobile shading, the plant growth, especially of sensitive plants, promoted by the additional light / dark cycles.

In summary, it can be stated that the new The shading system also provides a low level of light due to the permanent partial shading of plants that need light leads to good growth. The interaction of full light and full shade in summer leads to climate modulation, which can have a good influence on the plant. In addition, the fuel savings with the new shading system very high.

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Claims (9)

2819793 claims 1.J shading device on a greenhouse, characterized in that the device consists of light and Elements (5a, 5b, 6a, 6b), which are arranged on the underside of the roof surface and / or in the same, and that at least individual (5a, 6a) of these elements (5a, 5b, 6a, 6b) fixed and attached at a distance from one another are to effect at least a permanent partial shading of the interior. 2. Shading device according to claim 1, characterized in that the remaining elements (5b, 6b) between a first layer producing full shading and a second layer producing partial shading Position are movably arranged, and that means for moving these elements (5b, 6b) between their two layers are provided. 3. Shading device according to claims 1 and 2, characterized in that the elements foils (5a, 5b) or plates (6a, 6b), and that the movable foils (5a) or plates (6a) are completely in the second layer can be pushed under the stationary foils (5b) or plates (6b). 609848/0255 4. Shading device according to claim 1, characterized in that the stationary elements (6a) as solar collectors are trained. 5. Shading device according to claim 1, characterized in that that the stationary elements are aluminum foils, which are in strips or in a checkered pattern on the Are laid on the underside of the roof area. 6. Shading device according to claim 1, characterized in that about 50 % of the roof area are covered by the stationary elements. 7. shading device according to claim 1, characterized in that the elements made of heat-insulating material are made, and that the interior facing surfaces are covered with reflective material. 8. A method for operating the shading device according to claims 1 and 2, characterized in that the
Means for displacing the movable elements are automatically controlled by a brightness sensor, that the brightness sensor is set to a low and a high light intensity setpoint, that 609848/0255 in the case of irradiation below the low setpoint, the movable elements move into the partially shaded one Position are shifted, and that with an irradiation which is above the high setpoint, the movable Elements can be moved to the fully shaded position. 9. The method according to claim 8, characterized in that with an irradiation which is between the two sol - evaluate lies, the movable elements clockwise alternating in the half-shaded and the fully-shaded Position are shifted, their respective temporal stay in the fully shaded position proportional to the measured irradiation is. The representative: 609848/0255 Blank page