JP6429024B2 - Greenhouse for plant cultivation - Google Patents

Description

  The present invention relates to a greenhouse for plant cultivation using sunlight, and more particularly to a greenhouse that can be supplemented when sunlight is insufficient, such as in winter, and the temperature of a planting area can be easily controlled.

For example, as shown in Patent Document 1, supplementary light using a light source such as a metal halide lamp, a high-pressure sodium lamp, or an extra-high-pressure sodium lamp when sunshine is insufficient has been proposed.
However, it is not practical to use measurement means such as a photon meter for lighting control of an auxiliary light source because the system becomes complicated and expensive.
Further, for example, in the winter season such as the Hokuriku region, there is a case where there is a shortage of sunshine due to rainy weather or the like, but it is necessary to prevent an abnormally high temperature in the greenhouse during a sunny day.
In such temperature management, a complicated system is expensive and therefore not practical, and a system that is as inexpensive as possible considering the production value of plant cultivation is expected.

Japanese Patent Laid-Open No. 10-201368

  An object of the present invention is to provide a practical greenhouse for greenhouse cultivation that has a simple structure and is easy to supplement and control temperature.

  The greenhouse for plant cultivation according to the present invention is a greenhouse body using sunlight, and is disposed inside the greenhouse body, and is a translucent covering a planting area from above so as to form an opening at the bottom. An internal house part composed of a body, a temperature sensor part in an inner ceiling part of the greenhouse main body part, a supplementary light source in the internal house part, and a flashing control of the supplemental light source in the temperature sensor part It is controlled based on the measured value.

Here, the greenhouse main body is also called an agricultural house, etc., and all greenhouse structures used to grow plants, such as those made into a dome with a resin sheet such as a vinyl sheet, or a house framed with glass, etc. Is included.
In the present invention, the internal house part is a planting area where the supplementary light source and the plant under it are cultivated so that heat generated from the supplementary light source installed inside can also be used as heating of the planting area. A structure covered with a cover sheet.
In this case, the lower part of the inner house part is opened so that the planting area does not become abnormally hot.
As described above, the present invention has a double structure of the greenhouse main body portion and the internal house portion arranged inside thereof, and the supplementary light source can be used as a heating means by providing the supplementary light source in the internal house portion. The characteristic is that the intensity of sunshine could be determined by the temperature of the inner ceiling of the greenhouse main body.
Therefore, even without using expensive measuring equipment such as an optical quantum meter, it has versatility such as a temperature sensor and a timer, and can be controlled with inexpensive equipment.

In the present invention, there is a cold air blocking fence around the lower opening of the internal house, and the warm air reflux control for returning the warm air from the inner ceiling to the planting area inside the internal house You may make it have a means.
Using the property that warm air is generated in the upper part and cold air is likely to accumulate in the lower part, the cold air intrusion into the internal house part is blocked by the surrounding cold air shielding fence part, and the warm air in the ceiling part of the greenhouse body part Can be refluxed into the planting area.

In conventional greenhouses, the north side wall is made of glass, vinyl sheet, etc., just like other walls and roofs, but this north side wall surface has no effect on light absorption, but rather dissipates heat to the outside. End up.
Therefore, in the present invention, a heat storage part may be formed on the side wall part located on the north side of the greenhouse main body part.
With this heat storage section, it is possible to prevent the inside of the greenhouse from being lowered in a time zone when the outside air temperature is low in the early morning.
Here, the heat storage unit refers to one that absorbs the heat of sunlight and has heat storage properties. From the viewpoint of being inexpensive, water may be put into a plastic container or the like to form a heat storage unit.

In the present invention, the planting area becomes abnormally hot by having water spray type cold air generating means for preventing the planting area of the internal house part from becoming abnormally high temperature and / or ventilation means with outside air. It is preferable to prevent this.
Here, the water spray spray type cold air generating means is a method of spraying water in the form of a drill and generating cold air by the heat of evaporation of the water. It means to discharge inside air to the outside.

  The greenhouse for plant cultivation according to the present invention can be constructed with a simple system using a combination of a temperature sensor and a timer for temperature control, and is inexpensive and practical.

The structural example of the greenhouse which concerns on this invention is shown. The inside photograph of the greenhouse which concerns on this invention is shown. The control flowchart of the greenhouse which concerns on this invention is shown. A comparative example of Kanazawa City and Utsunomiya City is shown. The temperature survey results inside and outside the greenhouse are shown. The example of the thermal storage layer provided in the north wall is shown. The measurement results of heat quantity and internal water temperature of the heat storage layer are shown. The preliminary experiment of a heat storage layer (tank) is shown. The water temperature change of the thermal storage tank of FIG. 8 is shown.

Irradiation of light necessary for photosynthesis is indispensable for plant growth.
As shown in Figure 4, the Hokuriku region, for example, has a large number of sunny days in the winter, and in Ishikawa Prefecture, the amount of vegetable production is about 10% compared to Tochigi Prefecture in northern Kanto, where the average temperature is lower at the same latitude. (The meteorological data in Fig. 4 is based on the data published by Kanazawa Local Meteorological Observatory and Utsunomiya Meteorological Observatory, and the amount of vegetable production is based on the announcement by the Ministry of Agriculture, Forestry and Fisheries).
On rainy days, the photosynthetic effective photon density (PPFD) is about 60 μmol ⁻² s ^−1, which is insufficient for PPFD 150 μmol ⁻² s ⁻ necessary for promoting photosynthesis.
Since there is an amount of solar radiation of about 60 μmolm ⁻² s ⁻¹ even in winter, etc., the light intensity of supplementary light alone may be set by setting the light source and the distance from the light source to the medium with a target of 90 μmolm ⁻² s ^−1. .
As the supplementary lighting control method, it is desirable to control the lighting when the photon density is 100 μmolm ⁻² s ⁻¹ or less.
However, photon meters are expensive and complicated to control, making them difficult for ordinary farmers to use.
In the present invention, a method is employed in which the light intensity is measured for the temperature of the ceiling of the greenhouse, and supplementary lighting is performed when the temperature falls below a certain value (20 ° C. in the experiment).
As a preliminary survey, the graph of FIG. 5 shows the results of investigating the relationship between the temperature (temperature) of the ceiling of the greenhouse main body in the severe winter season of Hokuriku and the outside air temperature.
From this graph, it can be seen that when there is insufficient sunlight such as snow, it can be determined by the temperature of the ceiling.

<Ceiling warm air recirculation control>
In winter crop cultivation facilities such as Hokuriku, energy must be used for supplementary light, so it is necessary to devise technical measures to control temperature with energy conservation.
As shown in FIG. 5, when there is even a little sunshine, the temperature of the greenhouse rises, and warm air accumulates particularly near the ceiling.
Therefore, FIG. 1 shows an example of a greenhouse structure according to the present invention that uses such characteristics of the greenhouse to compensate for the lack of sunshine with supplementary light, and FIG. 2 shows a photograph of the inside of the greenhouse used for the experimental evaluation.
The shelf was installed in the greenhouse main body part 11 which formed the roof and the four wall parts with the translucent body, and the planting area 20 which consists of a planting shelf was provided.
The height of the planting shelf is set in consideration of workability, the height of the supplementary light source 13, and the like, but is at a level of 0.8 to 1.2 m.
An internal house portion 12 made of a translucent cover is provided so as to cover the upper portion of the planting area 20.
The internal house portion 12 is composed of an upper surface portion 12a and side portions 12b that hang from the peripheral portion and surround the four sides.
At the lower end of the side part 12b, there is an opening 12c having a gap of 0.6 to 0.8 m between the floor 12b and the floor.
Cold air made of a vinyl sheet or the like having a height of 0.9 to 1.0 m is formed in the peripheral portion outside the opening 12c with a horizontal clearance of 0.1 to 0.2 m from the side portion 12b. A barrier fence 14 is erected.
This cold air interception fence part 14 has the effect | action which prevents that the cold air accumulated under flows into the planting area 20 side.
Conversely, when the temperature of the internal house portion is lowered by water spray cold air described later, it acts as cold air retention.
A supplementary light source 13 for compensating for the lack of sunshine is arranged inside the internal house portion 12.
By providing a plurality of supplementary light sources 13 at an appropriate height inside the internal house portion 12, heat generated from the light sources can be used as heating.
A duct 15 having a suction port 15c in the ceiling as a warm air recirculation control means for returning the warm air in the inner ceiling portion of the greenhouse main body 11 into the planting area 20, and a discharge port 15d disposed in the internal house portion 12. Was provided.
In this example, an aluminum foil duct having a diameter of 150 mm was installed from the inner ceiling of the greenhouse main body 11 to the planting area.
A booster fan 15a for returning the ceiling warm air to the thermostat sensor installation position via the duct was installed in the duct 15.
In addition, a ventilation fan 15b that operates when it senses that the thermostat is in the proper temperature range was installed on the floor side of the booster fan.
Thereby, when the temperature is 20 ° C. or more and 32 ° C. or less, the ceiling warm air is refluxed to the vicinity of the medium.

Conventionally, the wall surface on the north side of the greenhouse is generally made of glass or vinyl, like other wall surfaces and roofs.
However, the north side wall of the greenhouse has no effect on light absorption, and has a large heat flow rate, which is a loss in terms of preventing low temperatures.
Therefore, in the present invention, the heat storage member is disposed along the north wall surface, and will be described below.
A shelf is made along the north side wall, and a poly tank filled with water is arranged side by side as shown in FIGS. 6 (a) and 6 (b).
For example, on the north wall of a greenhouse with a length of 50 m and an eave height of 2 m, a total of 538 20L plastic tanks with a length of 137 can be installed with 137 pieces in the length direction and four levels in the height direction.
That is, 10.8 ton of water can be accumulated on the north side wall.
Accumulation of 1300 MJ is possible on the assumption of a sunny day on the winter solstice, and the maximum water temperature in the heat storage tank reaches a maximum of 28.3 ° C on the assumption of a sunny day on the winter solstice.
When heat storage tanks composed of this polytank are arranged on the north wall perpendicular to the floor, they can be calculated as follows, and the calculated values are shown in FIG.
A: The amount of heat absorbed by the heat storage tank.
B: Amount of increase in water temperature due to the amount of absorbed heat Calculation of the amount of absorbed heat in the heat storage tank is as follows.
At: Surface area facing south side of 538 plastic tanks W: Direct solar radiation: 1000 Jm ⁻² S ⁻¹
θ: Solar altitude: Calculateable with position and time k: Greenhouse glass reflection and absorptance: 0.1 (transmitted light is 0.9)
Q = Σ (1-k) · W · At · COSθ
From this, it can be seen that the heat storage effect is higher in the winter period when the incident angle of sunlight is lower.

A structural photograph of a preliminary experiment of a heat storage tank substituted with a PET bottle is shown in FIG.
The measurement results are shown in FIG.
<Preliminary experiment of heat storage tank>
Thermal storage test using four types of PET bottles A. Water is sealed in a transparent PET bottle. Cover individual PET bottles with black vinyl cover and fill with water. Water was enclosed in the same transparent PET bottle as A, and the whole shelf was covered with black vinyl.
D. PET bottle filled with black liquid. Black liquid is 0.5%
Activated carbon, 1% dispersant (polyvinylpyrrolidone), 40% ethylene glycol for freezing prevention and the remaining amount is water.
Even in this preliminary experiment, the heat storage effect can be confirmed. For example, the water temperature of about 10 ° C. is maintained even at the early stage when the temperature is lowered to about 0 ° C. at a height of 1 m in the greenhouse.

<Fence with water spray cooling and cold air retention>
The temperature in the greenhouse exceeds 40 ° C. on a sunny day in winter as shown in FIG.
As a countermeasure against this high temperature, water is sprayed by a one-water spray nozzle for gardening in a space surrounded by a non-woven fabric (Nonwoven) as shown in FIG.
Cool air that has been blown from the outside by a fan (Mist fan) and decreased due to the heat of transpiration of water is blown toward the medium.
Cooling air can be supplied to the vicinity of the medium while preventing water droplets from being applied to the planting with a cooling system that combines the mechanism of water spray cooling and pad and fan.
Since the cold air accumulates below, the high temperature in the vicinity of the planting is prevented by installing the cold air blocking fence 14 up to the height of the planting.
Since the cooling effect of water spray cooling depends on the saturated water vapor pressure of air, it is often the limit to lower the temperature by about 5 ° C.
Therefore, ventilation with outside air is used for the lacking part.
Even if the outside air is directly introduced into the internal house, the phenomenon that the warm air stays upward and the cold air passes from below and the temperature of the entire planting area does not drop occurs.
In order to prevent this, the duct 17 with the fan 17 a for introducing the outside air is installed in the middle stage of the internal house part, and the warm air exhaust fan 16 a is connected from the upper stage of the internal house part 12 to the outside of the greenhouse via the duct 16. The high temperature of the planting part can be avoided.
<Flow chart for controlling temperature and light>
FIG. 3 shows a flow chart for controlling temperature and light. The light source, the fan, and the water supply electromagnetic valve are controlled only by the signals from the timer and the thermistor.
The simple structure is inexpensive and the control reliability is high.
More specific description will be given below.
When the ceiling temperature (Ceiling temp.) Is 20 ° C. or lower between 8:00 and 17:00, the auxiliary light source is turned on.
When the temperature of the planting area exceeds 28 ° C. between 8:00 and 17:00, the watering pump and the mist fan are operated, and the hot air discharge fan and the outside air introduction fan are operated as necessary.
If the temperature of the ceiling is between 20 ° C. and 16:30 and not higher than 32 ° C., the warm air reflux duct fan is operated.

11 Greenhouse Body 12 Internal House 13 Auxiliary Light Source 14 Cold Air Blocking Face 20 Planting Area

Claims (4)

A greenhouse main body using sunlight, and an inner house portion made of a translucent material that is disposed inside the greenhouse main body and covers the planting area from above so as to form an opening in the lower portion,
A temperature sensor on the inner ceiling of the greenhouse body,
Having an auxiliary light source in the internal house part,
The greenhouse for plant cultivation, wherein blinking control of the supplementary light source is controlled based on a measurement value of the temperature sensor unit.   Having a cold air blocking fence around the lower opening of the internal house, and having warm air recirculation control means for recirculating the warm air from the inner ceiling to the planting area inside the internal house. The greenhouse for plant cultivation according to claim 1 characterized by the above-mentioned.   The greenhouse for plant cultivation according to claim 1 or 2, wherein a heat storage part is formed in a side wall part located on a north side of the greenhouse main body part.   The water spray type cold air generating means for preventing the planting area of the internal house part from becoming an abnormally high temperature or / and a ventilation means with outside air according to any one of claims 1 to 3 Greenhouse for plant cultivation.