Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G9/00—Cultivation in receptacles, forcing-frames or greenhouses; Edging for beds, lawn or the like
  • A01G9/24—Devices or systems for heating, ventilating, regulating temperature, illuminating, or watering, in greenhouses, forcing-frames, or the like
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G9/00—Cultivation in receptacles, forcing-frames or greenhouses; Edging for beds, lawn or the like
  • A01G9/14—Greenhouses
  • A01G9/1469—Greenhouses with double or multiple walls
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
  • E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
  • E04D13/04—Roof drainage; Drainage fittings in flat roofs, balconies or the like
  • E04D13/064—Gutters
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
  • E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
  • E04D13/17—Ventilation of roof coverings not otherwise provided for
  • E04D13/174—Ventilation of roof coverings not otherwise provided for on the ridge of the roof
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F7/00—Ventilation
  • F24F7/02—Roof ventilation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
  • Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
  • Y02A40/25—Greenhouse technology, e.g. cooling systems therefor

Definitions

• the invention relates to a roof structure for a greenhouse or warehouse, comprising gutters extending mutually parallel and in a longitudinal direction and a raised cover extending between the gutters, which cover comprises a support structure supported on the gutters, an outermost translucent cover layer and an innermost translucent cover layer which jointly delimit a cavity.
• Such a roof structure is known from NL-A-8105447.
• the innermost cover layer thereof consists of a film which is tensioned between the mutually parallel frames adjacent to the gutter and the ridge.
• the cavity thus formed between the film and the outermost cover layer of rods and glass panels may be closed to achieve an insulation effect. This may considerably decrease the energy costs associated with heating the greenhouse.
• the cavity may also be open to discharge condensation water from it.
• the cavity may not be very thick and have a thickness of a few centimetres at the most. Also, the thickness of the cavity may be uniform, although that is not necessary. In such a case, it is ensured that a stationary layer of air is formed in the cavity, which has a favourable effect on the insulation.
• This known roof structure also has various disadvantages. As a result of the insulating effect of the cavity, it is difficult to remove snow from the roof structure. In known roof structures with single-layer panels, the snow melts away under the effect of heat in the interior of the greenhouse. The insulating effect of the double cover layers prevents that. However, a snow layer considerably blocks the incidence of light, which hampers cultivation.
• a further disadvantage is that, during the summer, the air in the cavity gets so hot that cooling in the evening and night proceeds too slowly.
• the hot air remains functional as a heat source for a considerable time.
• this is undesirable, as a rapid cooling of the culture overnight is desired.
• Patent FR2600230 describes a greenhouse which is formed by a support structure with two layers of transparent film attached thereto. In between these film layers, a space is formed that is kept under pressure by the outside air, using a fan and a pipe system. The air may be circulated through the intermediate space and be heated if necessary to counteract undesirable moisture condensation on the inside of the greenhouse.
• the pipe system in FR2600230 is unnecessarily complex and installing it is labour- intensive.
• An object of the invention is to provide, according to a first aspect, a roof structure which, on the one hand provides advantages of good insulation and energy saving, and with which on the other hand the above-mentioned disadvantages can be avoided.
• the roof structure according to this first aspect comprises ventilation means which discharge into the cavity and are adapted for ventilating the internal space of the cavity.
• ventilation is associated herein with the displacement of gas, and air in particular (as "ventilation medium").
• ventilation medium Normally, inside the cavity of the roof structure according to this aspect of the invention, a stationary layer of air is present, so as to ensure the desired insulation.
• the ventilation means can be put into operation. The air in the cavity may then be replaced by relatively hot or relatively cold air, depending on the desired effect.
• the roof structure In connection with supplying or discharging the ventilation air, the roof structure is provided with a ventilation duct that extends along the cavity, and which is connected by at least one opening (preferably via a series of openings extending in the
• the ventilation duct forms part of the ventilation means for exchanging a ventilation medium between that channel and the cavity through the at least one opening.
• Gutters exhibiting a tubular shape are known.
• This tubular shape provides the gutter with a certain desired strength and rigidity, at relatively low transverse dimensions. This promotes incidence of sunlight into the greenhouse.
• the tubular duct in the interior of the gutter has the advantage that it can be used to discharge condensation water from the inside of the cover layer.
• these tubular ducts may be exploited by also letting these function as ventilation channel, via which ventilation air can be supplied to, or discharged from, the cavity.
• the use of the already present gutter with tubular shape as a ventilation channel provides a simplification of the ventilation facility, and makes it possible to implement it more robustly.
• the ventilation air may be supplied or discharged uniformly over the entire length of the cavity. Consequently, the outermost cover layer can also be uniformly heated to remove snow.
• the tubular shape of the gutter is also adapted for discharging condensation water from an interior side of at least one cover layer.
• the gutter may be provided with a condensate receiving ledge beneath the outermost cover layer; in that case, the opening(s) or groove may be located at the level of this condensate receiving ledge.
• At least one of the cover layers comprises a film.
• the cover may comprise at opposite sides of the cavity a fastening section with an undercut chamber for the film.
• the film has a respective longitudinal thickening on opposite edges, so that each longitudinal thickening extends into the undercut chamber of the respective fastening section.
• the cavity is compartmentalised in the transverse direction, in other words: provided with partitions oriented in the transverse direction of the ridge towards the gutter.
• the cavity comprises several adjacent compartments extending in a transverse direction, inside each of which an air layer is located.
• Such a compartmentalisation has the advantage that inside these the formation of a stationary air layer is promoted more strongly.
• the greenhouse or the warehouse normally stands on (a very slight) slope, viewed along the longitudinal direction parallel to the gutters and the ridges. The reason for this is to improve drainage from the gutters. As a result of this slope, however, undesirable flows in the longitudinal direction may occur inside the cavity, which reduce the insulation capacity.
• a compartmentalisation wall may extend in the transverse direction inside the cavity, which wall is connected to the outermost and innermost translucent cover layers.
• a compartmentalisation wall may, for example, be formed by a metal profile, or a foil strip or the like.
• the compartmentalisation may be achieved without using such a separate compartmentalisation wall, if the film between both longitudinal edges thereof is attached to the other cover layer by means of a fastening construction which extends in the transverse direction.
• the film may be fastened with suitable clamps to the rods of a cover layer consisting of rods and glass panels.
• valve means are provided for opening or closing the ventilation means.
• the cavity When open, the cavity may be ventilated.
• the valve means When the valve means are closed, the air in the cavity is stationary, so that the insulating effect is ensured.
• valve means it is not always necessary to apply valve means. If the ventilation means have openings for supplying air to and discharging air from the cavity that exhibit a certain throttling effect, then it may be sufficient to switch the ventilation means on or off. Furthermore, supply and discharge openings may be provided at various height levels.
• the valve means for closing or opening the cavity may be implemented in various ways.
• the cavity is delimited by a longitudinal seal running parallel to the gutter, in particular, a closing section extending in the longitudinal direction, with at least one closable or non-closable opening, preferably a series of closable openings or a groove extending in the longitudinal direction of the seal, which discharge(s) into the internal space of the cavity.
• the variant including a series of openings or a groove promotes the uniform flow of ventilation air through the cavity.
• the cover of the greenhouse according to the invention may be implemented in several ways.
• One example is a greenhouse with two cover layers consisting of film, which are supported by rafters that extend between both gutters. These rafters may exhibit a curved shape, so that the highest point of the cover is located in the middle between the case, one gutter may function as supply for a ventilation medium, and the other gutter as discharge for that ventilation medium.
• a ridge may be located at the highest point of such a cover.
• the cover may be implemented in other ways, such as with a ridge located between the gutters at a higher level, an outermost cover layer on opposite sides inclined downwards from the ridge and rods towards an associated gutter for translucent panels between rods parallel to each other and a gutter, in which the innermost cover layer extends under a series of rods and panels on one side or both sides of the ridge.
• the outermost cover layer may be made of glass panels or film.
• the innermost cover layer may also be made of film or glass panels.
• the outermost cover layer consists essentially of glass panels and the innermost cover layer consists essentially of film, wherein the cavity is formed between the glass panels and the film.
• the longitudinal closure may be located at various positions at a distance from the gutter. According to a first option, this longitudinal closure coincides with the ridge. It is also possible to implement the longitudinal closure with a separate section that is located adjacent to or abuts the ridge. According to a further possibility, the longitudinal closure may be implemented as a longitudinal beam or transom resting between the gutter and the ridge. In the latter case, a ventilation window may be provided that is hingedly connected on one edge to the ridge, and cooperates at an opposite edge with the longitudinal beam or the transom, or vice versa.
• this roof structure is implemented such that it is entirely provided with an innermost cover layer as described herein above.
• a further inner layer is provided that extends under the other series of rods and panels to the other side of the ridge, thereby forming a further identical cavity that connects on one side to the further gutter and on the opposite side to a further longitudinal seal, wherein further ventilation means that discharge into the further cavity are provided for ventilating the internal space of the further cavity.
• the ventilation means may comprise an active fan for exchanging ventilation medium with the internal space of the cavity.
• This fan may be connected to the ventilation duct, for example to a tubular duct in the tubular channel mentioned above.
• the active fan may be implemented to be selectively switchable, so that during
• thermal stabilisation time of the air flow may depend strongly on the locations of the ventilation openings and the heating and/or cooling elements, as well as on the thermal properties of the ventilation ducts used. This switchability of the fan allows adjustment of the air flows in such a way that the thermal stabilization time of and/or losses in the air flow can be reduced. However, it is not always necessary to apply an active fan. The desired ventilation would also be achievable if the ventilation means comprise the above-mentioned openings located at various heights.
• the ventilation means may be adapted for exchanging the ventilation medium between the internal space of the cavity and the space enclosed by the roof structure and/or with the space outside the roof structure.
• a second aspect of the invention concerns a method for operating a roof structure for a greenhouse or warehouse.
• the roof structure comprises mutually parallel gutters and a raised cover extending between the gutters, which cover comprises a support structure supported on the gutters, an outermost translucent cover layer as well as an innermost translucent cover layer, which together delimit a cavity and which are supported by the support structure, wherein the roof structure is provided with a ventilation duct that extends along the cavity and that is connected via at least one opening to the interior of the cavity, wherein at least one of the gutters comprises a tubular shape which defines the ventilation duct.
• the method according to this second aspect comprises:
• the air supplied into the cavity may originate from the interior of the greenhouse, for example, in connection with the melting of snow on the roof in winter. It is also possible to supply cold air or conditioned air.
• the method may, to operate a roof structure wherein the ventilation means comprise an active fan for exchanging ventilation medium with the internal space of the cavity, comprise the steps of:
• the openings in the cavity - through which the air enters the cavity and/or leaves the cavity- with a valve or valves may exhibit a throttling effect that, on the one hand, enables passage of air under the effect of the pressure difference generated by the fan, but on the other hand ensures that the air remains in a more or less stationary state when the fan is inactive.
• valve means in connection with operating a roof structure wherein valve means are provided for opening and/or closing ventilation means, may comprise the steps of:
• the supplying and discharging of air during the second time period comprises: discharging air from the cavity via the at least one opening and through the ventilation duct and supplying air directly from an inner part of the greenhouse or the warehouse into the cavity to create the heating effect, the cooling effect and/or the drying effect in the cavity.
• the roof structure encloses or covers an inner region
• heated or cooled air from this inner region may be drawn into the cavity by the underpressure.
• the air does not need to flow through the ventilation duct first, so that any thermal losses and/or supply delays may be reduced.
• Figure 1 schematically shows one half of a roof structure according to an embodiment
• Figure 2 shows the detail II of Figure 1 at a larger scale
• Figure 3 shows detail III of Figure 1 at a larger scale.
• the part of a roof structure shown in Figure 1 consists of a gutter 1 and the cover indicated as a whole with 2, of which only part is shown.
• the gutter 1 may be supported by columns (not shown) in a known way.
• the cover 2 consists of rods 3 extending between the gutter 1 and the ridge 5. Between the gutter 1, the rods 3 and the transom 4 or the ridge 5, glass panels 15 are accommodated.
• Undercut sections 6 are fastened, onto which a film 7 is suspended which extends underneath the glass panels 15 and the rods 3.
• the film 7 has thickenings 9 on the edges, which are accommodated in the chamber of the undercut sections 6.
• an essentially airtight cavity 8 is formed that essentially exhibits a uniform thickness.
• the gutter 1 In connection with the discharging of condensation which accumulates on the underside of the cover 2, the gutter 1 is provided with condensate ledges 10, wherein condensation discharge openings 11 are located.
• the gutter 1 has a tubular duct 12 in which the condensate moisture is discharged.
• the stationary air inside the cavity 8 has an insulating effect on the cover 2.
• the cover 2 is implemented in such a way that the cavity 8 of the cover 2 is connected more or less airtight to the openings 1 1 in the condensation ledge 10 as shown in Figure 2. Furthermore, an active fan 13 is connected to the tubular duct 12 into which the openings 11 discharge. In the transom 4, a closable opening or series of openings 14 is provided as shown in Figure 3.
• the cavity 8 may for example be heated in connection with melting of snow located on the cover 2.
• the active fan 13 may also be adapted for generating a reversed air flow, so that the air through the openings 1 1 can be withdrawn from the cavity 8, so that an underpressure is created inside the cavity 8. As a result of the underpressure, further air can be supplied through the closable opening(s) 14 via opened valve(s) 17 into the cavity 8. In the case that the roof structure encloses or covers an inner region, heated air may be drawn in from this inner region 8 into the cavity as a result of the underpressure. By applying this reversal, any heat losses and/or supply delays of heated air (for example, as a result of a heat capacity of the gutter 1 with tubular duct 12) may be reduced.
• the active fan 13 may even be implemented selectively switchable to reverse the air flow in a controlled way, for example in anticipation of or in response to changing environmental variables that may cause a change in the expected heat losses.
• the ventilation window 16 is rotatably suspended on the ridge 5. When closed, this ventilation window 16 abuts upon the transom 4. If no ventilation is provided, the valve 17 may be closed so that a stationary layer of air is ensured in the cavity 8, which guarantees a good insulation.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Greenhouses (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2014
  • 2014-05-01 NL NL2012731A patent/NL2012731B1/nl not_active IP Right Cessation
• 2015
  • 2015-05-01 EP EP15728205.4A patent/EP3136838A1/en not_active Withdrawn
  • 2015-05-01 WO PCT/NL2015/050298 patent/WO2015167338A1/en active Application Filing

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