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
• • 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

• This invention relates to an arrangement and method, enabling the refrigeration of cooling water needed for dehumidifying and cooling greenhouse air, as well as to a greenhouse equipped with an arrangement of the invention.
• An objective in modern greenhouse production is to regulate the greenhouse climate for making it as consistent as possible with conditions optimal from the standpoint of plant growth.
• the greenhouse In optimal growth conditions, depending on the cultivated plant, the greenhouse has a temperature of about 18-30°C, an air moisture of about 60-90%, and a carbon dioxide concentration of more than 1000 ppm.
• the optimal growth conditions call for a good management of temperature, moisture, and carbon dioxide concentration.
• the climate is regulated by means of vents and/or fans.
• the surplus heat supplied by solar radiation is removed from the greenhouse by means of ventilation.
• the demand of at least partial ventilation exists also in Finland for about 8 months of the year.
• the cooling of greenhouse air is enhanced by spraying the room with water in a mist as fine as possible.
• the evaporating water absorbs heat from greenhouse air and increases the air humidity.
• the effective use of spraying for the cooling of greenhouse air usually requires also ventilation in order to enable a removal of moist air from the room and to enable the spraying to continue.
• the maximum amount of sprayed water is less than 0,5 liters/hour/m 2 of greenhouse.
• Today's greenhouses do not enable a carbon dioxide level optimal from the standpoint of plant growth to be sustained during the period of a high radiation level, at which time it would offer a maximum benefit.
• the carbon dioxide escaping along with ventilation air would increase the required amount of carbon dioxide to such an extent that its distribution is not economically viable.
• Prior known climate management solutions for a closed or semi-closed greenhouse are relatively easy to carry out in conditions with an abundant supply of low-temperature cooling water.
• commercial greenhouse production is predominantly located in regions where sufficiently cold cooling water is not, at least not constantly, available. In many instances, available water can even in this case be refrigerated for cooling water by means of evaporators placed outside the greenhouse.
• Prior known are solutions, among others, in which cooling water is refrigerated in a fan equipped evaporator or a basin installed outside the greenhouse.
• the water used in refrigeration can also be cooled by means of cooling towers common in industrial use.
• a problem with solutions based on the fan equipped evaporator is the high energy consumption and high noise level of fans.
• the water itself is not an object of refrigeration, nor is it used in equipment within a greenhouse for cooling the greenhouse air.
• the indoor air cooling effect of water sprayed on the roof is restricted to cooling the roof surface instead of cooling the water sprayed on the roof and its use in greenhouse air dehumidification and refrigeration equipment.
• This patent application describes a method for the refrigeration of cool water needed in cooling and dehumidifying the air of a closed or semi-closed greenhouse. Likewise described is an arrangement for implementing the method and a greenhouse equipped with an arrangement of the invention.
• the arrangement according to the invention is characterized in that the water collection devices are provided on the greenhouse roof or in its vicinity so as to enable at least some of the water sprayed onto and collected from the roof to be conveyed gravitationally to air cooling and dehumidifying equipment present inside the greenhouse and/or further downward by spraying with nozzles included in the collection devices.
• the method according to the invention is characterized in that, in the method, warmed-up refrigeration water, which has been used for the dehumidifying and cooling of greenhouse air, is conveyed up onto a roof of the greenhouse and refrigerated by spraying it over an external surface of the roof, and also water, which has been refrigerated by spraying, is recovered for reusing it for dehumidifying and cooling the indoor air of the greenhouse.
• the greenhouse according to the invention is characterized in that the collection devices for water sprayed over the greenhouse roof are provided on the roof or in the vicinity of the roof so as to enable at least some of the water sprayed over and recovered from the roof to be conveyed directly to cooling equipment present inside the greenhouse and/or that the water collection devices present on the greenhouse roof are fitted with nozzles for spraying the cooling water further downward.
• the water used for drying and cooling the air space of a greenhouse is refrigerated by spraying it into the air on the greenhouse roof and by collecting water sprayed onto the roof to be reused for cooling and dehumidifying the indoor air of the greenhouse.
• the greenhouse roof functions as a collector of water to be sprayed and partly as an evaporator, the cooling of a roofing material further enhancing the conduction of heat out of the greenhouse.
• the cooling capacity of water in a method of the invention is based on the evaporation of subsequently sprayed water from the absorbing energy, and on the other hand, on the conduction of heat from the cooling water to outdoor air.
• the method according to the invention is applicable whenever the wet-bulb temperature of outdoor air is lower than the desired
• cooling water The required cooling water temperature depends on desired greenhouse conditions. For example, in the cultivation of cucumber, the refrigeration of a greenhouse can be effected by using cooling water with a temperature of about 20°C. The lower the wet-bulb
• the method is not generally applicable in tropical conditions, in which the outdoor air has both a high temperature and a high humidity.
• Performance of the method can be improved by using a cooling water storage whose water can be subjected also to e.g. nighttime refrigeration, at which time the interior of a greenhouse does not generally need cooling and conditions for chilling the water sprayed onto the greenhouse roof are usually more favorable than during the day.
• the water sprayed or conveyed onto the greenhouse roof can also be sprayed from eave-mounted collection devices downward partially or entirely by gravity, whereby the water is further cooled by evaporation. In certain conditions, this may be necessary for enhancing the refrigeration of water.
• the spraying of water from the eaves level into a gutter present at the lower part of a greenhouse wall may be sufficient for chilling the water without spraying water at all onto the greenhouse roof.
• the method can also be supplemented by the use of a heat pump for enhancing the refrigeration of cooling water and/or for recovering the energy of cooling water and making use of it in heating.
• the method comprises cooling simultaneously both water to be sprayed on the roof and the roof surface of a greenhouse.
• the roof surface cooling makes a contribution to greenhouse climate management.
• the arrangement has its effectiveness based on the refrigeration of water so as to enable its use within a greenhouse for cooling and drying the indoor air particularly in applications, wherein the water sprayed on the roof is conveyed directly by gravity to indoor greenhouse air cooling systems, such as Novarbo, thereby minimizing the energy used for pumping water.
• the amount of water to be sprayed onto the roof is very large - typically 50 to 150 liters per square meter of greenhouse in an hour.
• the amount of sprayed water can be regulated according to outdoor air conditions for attaining a required cooling performance.
• the invention enables making use of a roof surface in its entirety or just partially, depending on the conditions and indoor cooling system.
• the arrangement according to the invention comprises an assembly of devices necessary for carrying out the method.
• the arrangement includes: Devices for conveying water onto the roof of a greenhouse (Fig. 1, 1), devices for spraying water over the greenhouse roof, as well as a collection system by means of which the water sprayed over the roof is recovered and re-conveyed into the greenhouse interior to be used in equipment intended for the cooling and dehumidifying of indoor air. Operation of the
• the greenhouse according to the invention is a closed or semi-closed greenhouse, which is equipped with devices of the invention.
• the method and arrangement according to the invention enable cooling water used for the cooling and air humidity management of a partially or totally closed greenhouse to be refrigerated in a substantially more
• the refrigeration of water can be effected by making use of existing greenhouse structures and an extensive greenhouse roof surface area as a collector of sprayed water.
• the only necessary accessories are devices by which the water is conveyed onto the greenhouse roof and sprayed over an external surface of the roof, as well as collection devices by which the sprayed water is recovered and conveyed to be used in equipment intended for the cooling and humidity management of the greenhouse indoor air.
• the water storage included in the invention can be protected from light, whereby maintaining its cleanliness becomes substantially easier.
• the sprayed water refrigerates - depending on the dimensions of jets - towards the wet-bulb temperature of outdoor air, and the thereby chilled water can be used for the cooling and humidity management of greenhouse indoor air.
• the method according to the invention enables reducing greenhouse thermal losses, e.g. during a cold night when the temperature of outdoor air is substantially lower than that of sprayed cooling water.
• Fig. 1 shows an arrangement of the invention in a basic solution, wherein, in order to convey water which has warmed up within a greenhouse, the arrangement includes a piping (1) by means of which the cooling water, which has warmed up within a greenhouse, can be conveyed up onto a roof (6) of the greenhouse.
• the arrangement is further provided with nozzles (2) by means of which the cooling water can be sprayed over the greenhouse roof, as well as a collection gutter (3) by means of which the water, which has been sprayed over the roof and which has chilled during the spraying process, can be recovered and conveyed by way of a piping (4) to cooling equipment present inside the greenhouse or into a basin or water storage (5) associated with the greenhouse.
• Example 2 shows an arrangement comprising, in addition to the devices described in example 1, a piping (7) which enables cooling water to be conveyed gravitationally from the collection devices (3) of water sprayed over the roof (6) directly to nozzles (8) included in cooling equipment present inside the greenhouse.
• Example 3 shows an arrangement comprising, in addition to the devices described in example 1, nozzles (9), which are fixed to a bottom of the gutter (3) present at the eave level of a greenhouse and which enable cooling water accumulating in the gutter to be further sprayed outside the greenhouse along a wall (10) into a collection gutter (11) present at a bottom part of the wall, and to be further conveyed therefrom along a piping to cooling equipment present inside the greenhouse.
• Fig. 4 shows an arrangement, wherein water to be refrigerated is conveyed by means of a piping (1) up onto a roof (13) of the multi-ridge or so-called block greenhouse and sprayed over the roof by means of nozzles (2) included in the piping. The refrigeration of water only takes place over a portion of the block house roof, and the collection of water is effected by making use of a rainwater collection system, the water returning directly to an internal greenhouse cooling system or into a basin or water storage (12) present under the greenhouse.

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• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Greenhouses (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=41263473

Family Applications (1)

Country Status (3)

Families Citing this family (2)

Family Cites Families (5)

• 2009
  • 2009-10-13 FI FI20096057A patent/FI20096057A0/fi not_active Application Discontinuation
• 2010
  • 2010-10-11 WO PCT/FI2010/050790 patent/WO2011045470A1/en not_active Ceased
  • 2010-10-11 EP EP10823101.0A patent/EP2488009A4/de not_active Withdrawn

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