DE3026845A1 - Greenhouse air conditioning system - has roof outlet conduit connected by passages leading downwards to heat accumulator - Google Patents

Abstract

The greenhouse air-conditioning system comprises an outlet in the roof and an inlet below it, the former consisting of a transparent flat air conduit extending for the entire length and breadth of the roof. This conduit (11) is connected via downwards passages (31) to a heat accumulator (28a,32,28), whose outlet (25) is connected to the inlet (19). The roof conduit has one or more inlet ports (30) from the greenhouse interior and which can be shut off, and there are similar ports (29) in the passages (31) near the floor (9). The passages can be at the walls, while the conduit inlets can be near the roof ridge.

Description

3026645

Vera Kiesel, née Rothkegel 8700 Würzburg

Air conditioning system in greenhouses

The invention relates to a system for conditioning the air in greenhouses with an exhaust air device in the Roof area of the greenhouse and a supply air device below the exhaust air device, the exhaust air device a transparent, extending essentially over the entire length and width of the roof of the greenhouse, Has flat air duct.

Such a system is known from DE-AS 2,721,434 become. With this system, the upper greenhouse zone can be effectively ventilated in "summer operation" Excess heat can be dissipated by cooling the roof surfaces, while in "winter operation" the roof-side Air duct converted into a heat-insulating double jacket is or forms a thermal insulation zone below the greenhouse roof, which prevents the heat loss of the Reduced roof area and consequently also the heating energy requirement. The amount of heat dissipated with this system when exposed to sunlight however, is lost. This is especially true in the transition period, when there is strong sunlight during the day

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can, so that ventilated and consequently heat dissipated and heated at night because of the relatively low outside temperatures must be, uneconomical.

There are also systems known in which with solar panels installed inside or outside the greenhouse, some of which are movable, the amount of heat radiated in is recorded. However, these constructions are very expensive and shade, if they are arranged inside the greenhouse, the plant crops in an undesirable manner.

The invention is based on the object of developing the system of the type mentioned in such a way that the in the greenhouse, especially in the transitional period, by exposure to sunlight Superfluous amount of heat introduced during the day is recorded and stored in such a way that it can be used when the outside temperature drops can be used again to heat the greenhouse in order to save energy costs.

According to the invention, this object is achieved in that the roof-side air duct extends over downward Air ducts are connected to a heat accumulator, the output of which is connected to the supply air device, wherein in As is known, the roof-side air duct has at least one closable room air inlet opening and also the downwardly extending air ducts at least near the

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Greenhouse floor with closable room air inlet openings are provided. If, for example, there is relatively strong solar radiation during the transition period, there is room air sucked into this through the inlet opening (s) on the underside of the ceiling-side air duct. That air has there if it is taken from the top of the greenhouse, it is already at a relatively high temperature and it is also heated when flowing through the roof-side air duct on its walls. This relatively strongly heated air is then advantageous Passed through the air ducts extending downwards into the heat accumulator in order to heat it up. The on this Cooled air is passed on to the supply air device and thus fed back into the greenhouse interior, to cool it.

When there is no solar radiation and the outside temperature drops If the greenhouse needs to be heated, the heat flow is reversed, i.e. that in the heat exchanger The stored amount of heat is given off to the air flowing through it and the air heated in this way is released via the supply air device reintroduced into the greenhouse in order to heat it in whole or in part. In this operating mode, the The indoor air inlet opening of the roof-side air duct is closed, while the indoor air inlet openings are in the air ducts extending below are open. Since these are close to the greenhouse floor, the circulating air becomes relative

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sucked deep and a temperature stratification avoided. The roof-side air duct forms one in this operating mode thermal insulation.

An expedient embodiment of the invention is characterized in that the air duct is itself connected at its two longitudinal edges with the area of the greenhouse walls by err below stretching air channels and having in the ridge area the closable air inlet opening (s).

If, according to yet another embodiment of the invention, the Heat storage is arranged under the greenhouse floor in the ground and / or in heat-storing mineral materials Reduced heat loss.

A further expedient embodiment of the invention is thereby characterized in that the heat accumulator has lateral longitudinal channels to which the air channels leading downward are connected are, as well as having a collecting channel connected to the supply air device between these longitudinal channels, and that the longitudinal channels are connected to the collecting channel by a plurality of heat exchange channels. The through these heat exchange channels, which can consist of drainage pipes, for example, heat the amount of heat given off - the adjacent soil and / or a heat-retaining mineral, which accordingly

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the thermal conductivity and the specific heat of the same a certain amount of heat is stored. The material in which the heat exchange channels are embedded, so should have good thermal conductivity and storage capacity for heat exchange to improve. The collecting channel is expediently arranged in the middle under the floor of the greenhouse.

If according to yet another embodiment of the invention in roof-side air duct a flat material, e.g. shading or heat protection material, e.g. in the form of foils and / or fabric is pulled through by means of ropes and rollers or the like in the direction from the ridge to the eaves or vice versa, the effectiveness of the circulating air heating in the roof-side air duct during storage operation and at the same time also the Improved thermal protection of the plants. Such "intermediate roof shading" causes a large part of the Heat conversion takes place in sunlight in the roof-side air duct. The result of the conversion from short to Long-wave radiation on this shading material converted and released amount of heat can be used in storage operation fed to the heat storage tank or, if the sunshine is too great in summer operation, with the exhaust air without any disadvantageous effects Impairment of the greenhouse climate discharged into the open air will.

Another additional advantage achieved by this measure is that, since most of the in heat

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converted radiation through the circulating air directly from the roof-side Air duct is discharged, the shading material can be more translucent than with the previously known Systems. This in turn means that more light is available in the greenhouse at the optimum temperature for plant growth.

According to a further embodiment of the invention, the heat exchange during storage cooling operation is further improved by that the sheet-like shading material in his Light and thermal radiation transmission is graded. This gradation is expediently carried out in the longitudinal direction of the Shading roller. It is thereby possible, especially in the Transition time the solar radiation depends on the outside temperature to be used in an optimal way for storage without having to accept great losses of light for the plants have to.

The invention will then be explained in more detail with reference to the drawings of exemplary embodiments. It shows:

Fig. 1 is a schematic cross section of a greenhouse with the system according to the invention, set to storage cooling operation;

Fig. 2 a horizontal section through the heat accumulator below of the greenhouse floor in the same mode of operation;

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Fig. 3 is a cross-section similar to Fig. 1, but accordingly the system works in storage heating mode;

Fig. 4 shows a horizontal section of the heat accumulator similar to Fig. 2 for the mode of operation according to Fig. 3 and

Fig. 5 is a schematic cross-section through a roof half of the greenhouse, which has a shading device in the roof-side Air duct shows.

The greenhouse 10 has an exhaust air device in the roof area, which extends over the entire length and width of the roof includes extending flat air duct 11, which is up through the greenhouse roof 12 and down through an air guide element 13 made of translucent material, e.g. acrylic glass, is limited. This air guide element 13 has in the ridge area one or more room air inlet openings 30, the by flaps 15 or inflatable film tubes (not shown) is or are lockable.

The air duct 11 is on both of its longitudinal edges in the eaves area connected to vertical air ducts 31 which extend down along the greenhouse side walls. In the longitudinal direction of the greenhouse, numerous such vertical air ducts 31 can be provided on both sides or one can Such an air duct can also be continuous over the entire length of the greenhouse. (In the illustrations, there are two

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only one vertical air duct 31 is shown by way of example.) Each air duct 31 has room air inlet openings 14 and 29, which are in the area of the eaves or near the greenhouse floor 9 arranged and can be closed by flaps 15, film tubes, or similar devices.

According to the invention, there is a heat accumulator under the greenhouse floor 9 arranged. This heat accumulator comprises two lateral ones Longitudinal channels 28 a, which can extend over the entire length of the greenhouse and on which the vertical air channels 31 are connected. In the middle between these longitudinal channels 28a, a collecting channel 28 is arranged, which laterally communicates with the longitudinal channels 28a through a plurality of heat exchange channels 32. All channels 28, 28a and 32 are embedded in the ground 33 and / or in heat-storing minerals. The collecting channel 28 is on one End through a vertical channel 25 with a supply air channel 19, expediently designed as a film tube, connected to the forms part of the supply air device and is arranged essentially over the length of the greenhouse below the air duct 11 is. Between the vertical channel 25 and the supply air channel 19 is an air conditioner (not shown) with a fan Air circulation switched on. There are also air ducts on the roof side 11 on the front side in the ridge area or directly on the ridge exhaust air fans (for summer operation).

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3Q26845

In Figs. 1 and 2 the system is set to storage cooling mode. Through the entry opening 3Q in the ridge area of the Greenhouse 10 is sucked in room air, which after both Pages flows through the air duct 11, delimiting the air duct from those warmed up by the solar radiation Areas, namely the greenhouse roof 12 and the air guide element 13 is heated. The air heated in this way then flows through the vertical air ducts 31 (which also extend over the entire length of the greenhouse, e.g. in the form of a double wall can) down into the longitudinal channels 28a of the heat accumulator. The room air inlet openings or intake openings 14 and 29 are closed in this operating mode. The heated air flows from the longitudinal channels 28a in the direction of the arrow due to the numerous heat exchange channels 32 with a relatively small cross section, however, overall large surface area for Collective duct 28 and through this via the vertical duct 25 and the air conditioning unit (not shown) to the supply air duct 19.

When the heated air flows through the exchange channels 32, it is cooled by the colder surrounding soil 33. Of the The area of the soil below the greenhouse floor 9 is thereby heated and it stores during this mode of operation a certain amount of heat, which in the other operating mode, namely the storage heating mode, returns to the greenhouse interior is fed.

In Figs. 3 and 4 the system is set to storage heating mode. The room air inlet openings 30 and 14 are

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closed, the room air inlet openings 29 near the greenhouse floor 9 are open. The roof-side air duct and the vertical air ducts 31 or double walls become a heat-insulating double jacket in this operating mode repurposed. As a result, heat losses to the outside atmosphere are reduced in this operating mode, which is important is when there is no solar radiation and the outside temperature drops, especially in the transition period at night. To avoid from temperature stratifications in the greenhouse, the room air is also above the floor 9 through the inlet openings 29 sucked in and via the lateral longitudinal channels 28a through the heat exchange channels 32 to the collecting channel 28, and from there guided via the air conditioning unit, not shown, into line 19 of the air intake device. The influences described above cooled air takes in the heat exchange channels 32 heat from the surrounding, during the storage cooling operation warmed up soil and is used in whole or in part to heat the greenhouse at correspondingly lower outside temperatures.

Fig. 5 shows a shading device 39, which a sheet-like shading material 35, for example in the form of a Has film, which is unrolled by means of a pull rope 36 via a roll-up device 37 from the roll 38 and into the Roof-side air duct 11 can be drawn in such that the film on both sides (or on one side) with the one flowing through the duct Comes into contact with air. Depending on how far this

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Shading foil is drawn into the channel 11, the amount of heat entering the greenhouse is reduced, with the Air flowing past during storage cooling mode (Fig. 1 and 2) also absorbs heat from the shading film and transported into the heat storage.

In "summer operation", fresh air is introduced into the greenhouse from outside through the supply air device and through the open Inlet openings 14 are sucked off through the air duct 11 towards the ridge. The room air inlet openings 29 are at this operating mode is closed, as is the opening 30.

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Claims (6)

Claims 1. System for conditioning the air in greenhouses with an exhaust air device in the roof area of the greenhouse and a supply air device below the exhaust air device, wherein the exhaust air device is located essentially on the has the entire roof length and width of the greenhouse extending, transparent, flat air duct, characterized in that, that the roof-side air duct (11) via air ducts (31) extending downwards with a heat accumulator (28a, 32, 28), the output (25) of which is connected to the supply air device (19), the roof-side Air duct (11) has at least one closable room air inlet opening (30) and also extends downwards extending air ducts (31) at least near the greenhouse floor (9) with closable room air inlet openings (29) are provided. 130066/0194 2. System according to claim 1, characterized in that the air duct (11) on its two longitudinal edges with the in the area the greenhouse walls are connected to the air ducts (31) extending downwards and in the ridge area the closable Has room air inlet opening (s) (30). 3. System according to claims 1 and 2, characterized in that the heat accumulator (28a, 32, 28) under the greenhouse floor (9) is arranged in the ground (33) and / or in heat-storing minerals. 4. System according to claim 3, characterized in that the heat accumulator lateral longitudinal channels (28 a) to which the downwardly guided air ducts (31) are connected and between these longitudinal ducts (28a) one with the supply air device (19) connected collecting channel (28), and that the longitudinal channels (28a) with the collecting channel (28) through a plurality of heat exchange channels (32) are connected. 5. System according to claim 1, characterized in that im Roof-side air duct (11) a flat material, e.g. shading or heat protection material (35), e.g. in the form of Sheets and / or fabrics by means of ropes (36) and rollers (37, 38) or the like in the direction from the ridge to the eaves or vice versa, is pulled through. 130066/0194 6. System according to claim 5, characterized in that the sheet material in its light and heat radiation through nonchalance is graded. 130066/0194