JP2023114201A - Solar power generation system in agricultural greenhouse - Google Patents

Abstract

To provide a solar power generation system in an agricultural greenhouse that can achieve both a high yield of crops throughout the year and the high-power generation efficiency of green power.SOLUTION: A solar power generation system 1 in an agricultural greenhouse of the present invention comprises: a house body 10 having a frame 11 installed on the ground and a transparent film 12 covering the frame 11 to demarcate a house space S; earth floor concrete 20 installed on a floor surface of the house space S; a cultivation facility 30 capable of being installed in the house space S; a solar power generation panel 40 arranged in contact with an upper surface of the earth floor concrete 20; transformer means 50 capable of converting DC power generated by the solar power generation panel 40 into AC power; heating means 60 capable of heating air in the house space S; and a plurality of power transmission means 70 electrically connecting the solar power generation panel 40 and the transformer means 50, the transformer means 50 and the heating means 60, and the transformer means 50 and an external transmission network G, respectively, wherein the system is configured so that at least a part of a total power generation amount can be selectively transmitted to the external transmission network G.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an in-house photovoltaic power generation system for agriculture, and more particularly to an in-house photovoltaic power generation system for agriculture capable of achieving both a high harvest rate of crops throughout the year and high power generation efficiency of green power.

The SDGs adopted at the United Nations Summit in September 2015 call for concrete measures against climate change caused by the effects of greenhouse gases. In response to these global trends, the Japanese government has set a numerical target of reducing real carbon dioxide emissions by 50% by 2050.
Along with the setting of specific numerical targets, private companies have also begun to take proactive measures to reduce carbon dioxide emissions. One of these efforts is the use of carbon-free, green power such as solar power and wind power.
Among these, in photovoltaic power generation, with the expansion of the feed-in tariff (FIT) system for renewable energy in 2012, large-scale megasolar photovoltaic power generation facilities were built across the country, and the amount of power generated nationwide is rapidly increasing. stretched to However, due to the continuous large-scale development, there is a shortage of land, and there is a nationwide shortage of places where solar panels can be installed.
In response to this situation, farming-type photovoltaic power generation (solar sharing), in which photovoltaic power generation is performed using the sky above agricultural land with a relatively large site area, has recently become widespread.
Cited Documents 1 to 3 disclose a solar-sharing type photovoltaic power generation facility configured by erecting pillars at predetermined intervals in farmland and installing photovoltaic panels on top of the pillars.

Japanese Unexamined Patent Application Publication No. 2020-10632 JP 2020-184987 A Japanese Patent Application Laid-Open No. 2014-236200

The prior art has the following problems.
<1> Since the photovoltaic panels cover the crops, the sunshine on the crops is blocked, which may hinder the growth of the crops and reduce the yield. Conversely, if an attempt is made to ensure sufficient sunshine for the growth of crops, the light-receiving area of the photovoltaic power generation panel will become smaller, making it impossible to obtain a satisfactory amount of power generation. In other words, there is a trade-off relationship between the yield of crops and the amount of power generated by the photovoltaic power generation panel, and both cannot be achieved at the same time. This has had the opposite effect of damaging crop yields in the name of "green power."
<2> Since crops and solar power generation panels are exposed to the open air, they are directly affected by natural phenomena such as typhoons, snowfall, volcanic ash, and yellow sand. As a result, crops may be damaged, and damage such as damage to solar power generation panels and mounts may occur.

An object of the present invention is to provide a photovoltaic power generation system in an agricultural house for solving the above-described problems of the conventional technology.

The in-house photovoltaic power generation system for agricultural use of the present invention comprises a house body having a frame erected on the ground and a translucent film covering the frame to define a house space, and a floor surface of the house space. Installed dirt floor concrete, cultivation equipment that can be installed in the greenhouse space, solar power generation surface material placed in contact with the top surface of the earth floor concrete, and DC power generated by the solar power generation surface material can be converted to AC. A plurality of power transmission systems that electrically connect the transforming means, the heating means capable of heating the air in the house space, the photovoltaic surface material and the transforming means, the transforming means and the heating means, and the transforming means and the external power grid, respectively. means for selectively transmitting at least part of the total power generation to an external power grid.

In the solar power generation system in an agricultural house of the present invention, the earth floor concrete has an installation groove, the solar power generation face material is installed in the installation groove, and the surface of the earth floor concrete and the surface of the solar power generation face material are flush. may be configured.

The solar power generation system in an agricultural house of the present invention is a floor heating facility in which the heating means heats a heat medium and circulates the heat medium in a heat transfer pipe arranged in the concrete floor to heat the concrete floor. There may be.

In the in-house photovoltaic power generation system for agricultural use of the present invention, a plurality of cultivation facilities are arranged along the longitudinal direction of the house body to form a cultivation facility array, and a plurality of photovoltaic surface materials are arranged along the cultivation facility array. They may be arranged to constitute a photovoltaic panel array, and the cultivation facility array may be sandwiched between adjacent photovoltaic panel arrays.

The in-house photovoltaic power generation system for agricultural use of the present invention may include a heat insulating material placed on the bottom surface of the earth floor concrete and a moisture-proof film laid on the bottom surface of the heat insulating material.

The in-house photovoltaic power generation system for agricultural use of the present invention has at least one of the following effects.
<1> Since the photovoltaic panel is placed on the floor of the greenhouse, the solar panel does not block sunlight on the crops. In addition, even if the photovoltaic face material is shaded by crops, the photovoltaic face material can indirectly receive light and generate power through diffused reflection of the film in the house body. Therefore, it is possible to achieve both a high yield of agricultural products and high power generation efficiency of green power.
<2> Since the inside of the house space can be maintained at a constant temperature by the heating means, it is less susceptible to climate and seasons. In addition, by accumulating heat in the earthen floor concrete from sunlight during the day and releasing it as radiant heat at night, the temperature difference between day and night can be reduced. As a result, crops can be grown stably throughout the year.
<3> By transmitting the heat of the photovoltaic face material to the earthen floor concrete, power generation loss due to high heat of the photovoltaic face material can be suppressed, and high power generation efficiency can be maintained.
<4> By achieving both the supply of green power and the harvest of agricultural products, we will achieve the goals of the SDGs: "2. Zero hunger,""7. Affordable and clean energy," and "12. Responsible consumption and production." 13. We can contribute to the achievement of concrete measures against climate change and 15. Let's protect the richness of the land.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing of the solar power generation system in an agricultural house according to the present invention. Explanatory drawing of the house body Explanatory drawing of the internal structure of a solar power generation system in a greenhouse for agriculture Explanatory diagram of cultivation equipment array and photovoltaic surface material array Explanatory diagram of how to operate a solar power generation system in an agricultural house (1) Explanatory diagram (2) of the operation method of the solar power generation system in the greenhouse for agriculture Explanatory diagram of how to operate a solar power generation system in an agricultural house (3)

Hereinafter, the in-house photovoltaic power generation system for agricultural use of the present invention will be described in detail with reference to the drawings. In addition, in order to ensure the visibility and comprehensibility of the drawing, the scale of the cultivation equipment and the like is reduced and the structure of the greenhouse body and the like is simplified and displayed on the drawing.

[Photovoltaic power generation system for agricultural greenhouses]
<1> Overall configuration (Fig. 1)
An agricultural house interior solar power generation system 1 includes a house body 10 having a house space S therein, a dirt floor concrete 20 installed on the floor surface of the house space S, a cultivation facility 30 installed in the house space S, and a dirt floor. At least a photovoltaic panel 40 installed on the upper surface of the concrete 20, a transformer means 50, a heating means 60, and a power transmission means 70 are provided.
The power transmission means 70 electrically connects the photovoltaic power generation surface material 40 and the power transformation means 50, the power transformation means 50 and the heating means 60, and the power transformation means 50 and the external power grid G, respectively. Depending on the design, a power receiving and transforming facility may be installed between the power transforming means 50 and the external power grid G.
The in-house photovoltaic power generation system 1 for agricultural use has one feature in that at least part of the total amount of power generated by the photovoltaic surface material 40 can be transmitted to the external power grid G. As shown in FIG.
The power transmitted to the external power grid G will contribute to the achievement of SDGs by selling it to third parties based on contracts as carbon-free green power, or by self-consignment to factories and offices owned by the company. be able to.

<2> House body (Fig. 2)
The house body 10 has a structure that protects the crops 32 from temperature changes, wind and rain.
The house body 10 includes at least a frame 11 erected on the ground and a translucent coating 12 covering the frame 11 to define a house space S.
In this example, as the house body 10, a pipe house is adopted in which a frame 11 composed mainly of single pipe pipes is covered with a coating 12 of a polyolefin film. is installed.
However, the structure of the house body 10 is not limited to the above. The point is that the film 12 should be translucent and have a structure capable of protecting the crops 32 .

<3> Dirt floor concrete (Fig. 3)
The dirt floor concrete 20 is a structure that constitutes the floor surface of the agricultural house.
The dirt floor concrete 20 is desirably installed over the entire floor surface in the house space S.
In this example, the dirt floor concrete 20 is provided with installation grooves 21 for accommodating the photovoltaic panel 40 . The depth of the installation groove 21 corresponds to the thickness of the photovoltaic panel 40 .
As a result, when the photovoltaic panel 40 is installed in the installation groove 21, the surface of the dirt floor concrete 20 and the surface of the photovoltaic panel 40 are flush with each other. It becomes easy and damage of the photovoltaic power generation surface material 40 can be prevented.
Also, in this example, a heat insulating material 80 is placed on the lower surface of the dirt floor concrete 20, and a moisture-proof film 90 is laid under the heat insulating material 80. As shown in FIG.
As a result, cold air and moisture from the ground under the moisture-proof film 90 can be blocked, and the efficiency of heating the house space S by the heating means 60 can be enhanced.

<3.1> Construction of earth floor concrete The earth floor concrete 20 is constructed, for example, by the following steps.
A gravel work is performed on farmland, and a moisture-proof film 90 is laid on the gravel work.
A heat insulating material 80 is placed on the moisture-proof film 90, and a formwork is placed around the outer periphery of the heat insulating material 80. - 特許庁
A tensile member 22 such as a lath wire mesh is placed on the heat insulating material 80 . The tensile member 22 is placed on the spacer to provide a space between it and the heat insulating member 80 to secure the thickness of the concrete covering.
Concrete is placed in the formwork and cured to build the earth floor concrete 20. - 特許庁

<3.2> Heat Storage Function The dirt floor concrete 20 has a heat storage function due to sunlight.
Since concrete has a high heat storage property, the surface of the dirt floor concrete 20 receives sunlight during the day, and heat is stored inside the concrete and radiated into the house space S as radiant heat over a long period of time. heating efficiency can be increased.
In addition, in this example, since the bottom surface of the photovoltaic panel 40 is in contact with the bottom of the installation groove 21 of the earth floor concrete 20, the heating of the photovoltaic panel 40 due to light reception is transferred to the earth floor concrete 20. As a result, it is possible to prevent the temperature of the photovoltaic power generation surface material 40 from rising, and prevent a decrease in power generation efficiency.

<4> Cultivation equipment (Fig. 3)
Cultivation equipment 30 is equipment for cultivating crops 32 .
In this example, the cultivation facility 30 employs a soil cultivation facility using an elevated planter 31 in which crops 32 are planted. However, the cultivation facility 30 is not limited to this, and may be, for example, a hydroponic cultivation facility.
In this example, the crop 32 is a tomato. However, other fruit vegetables such as cucumbers, eggplants, and strawberries, and leafy vegetables such as Japanese mustard spinach, spinach, and lettuce can also be used.
Since the structure of the cultivation equipment 30 in the agricultural house is known, it will not be described in detail here.
In this example, a plurality of cultivation facilities are arranged along the longitudinal direction of the house body to form a cultivation facility array (FIG. 4).

<5> Photovoltaic surface material (Fig. 3)
The photovoltaic panel 40 is a device that generates power from sunlight.
In this example, as the photovoltaic panel 40, a high-strength crystalline silicon type photovoltaic panel for road installation is adopted. However, the photovoltaic panel 40 is not limited to a photovoltaic panel, and may be a flexible photovoltaic sheet.
The photovoltaic panel 40 is arranged in the installation groove 21 of the dirt floor concrete 20 with the light receiving surface facing upward.
In this example, a plurality of photovoltaic panel members 40 are arranged along the cultivation facility array 30a to form the photovoltaic panel array 40a. 30a (Fig. 4).
The in-house solar power generation system 1 for agricultural use of the present invention has a structure in which the solar power generation surface material 40 is arranged on the floor surface in the house space S. Sunlight is not blocked by the photovoltaic panel 40. - 特許庁
In addition, even if the solar power generation surface material 40 cannot directly receive sunlight due to the shade of the crops 32, the solar power generation surface material 40 can indirectly receive the sunlight through the irregular reflection in the translucent coating 12 can receive light and generate electricity.

<6> Transforming Means The transforming means 50 is a component for converting the electric power generated by the photovoltaic panel 40 into alternating current.
In this example, as the transformer means 50, a power conditioner having an MPPT (maximum power point tracking control) function and a grid connection protection function is adopted.
The power transformation means 50 converts the direct current power (DC) generated by the photovoltaic power generation surface material 40 into alternating current power (AC) and transmits it to the heating means 60, the lighting equipment 13, etc., and transmits surplus power to the external power transmission network G send power to

<7> Heating Means The heating means 60 is a component for heating the air in the house space S. As shown in FIG.
In this example, as the heating means 60, a floor heating system is employed that heats the inside of the house space S through the dirt floor concrete 20 by a combination of a storage battery 61, a heat pump water heater 62, and a heat transfer pipe 63.
Specifically, when the earth floor concrete 20 is molded, the heat transfer pipe 63 is arranged in a loop in the earth floor concrete 20 by folding back the heat transfer pipe 63 throughout the mold. The heat transfer pipe 63 is filled with a heat medium 64 such as water.
Electricity transmitted from the transformer means 50 is stored in the storage battery 61, and the electric power is used to heat the heat medium 64 with the heat pump water heater 62, and the earth floor concrete 20 is heated by circulating the heat medium 64 in the heat transfer pipe 63. to heat the air in the house space S from the surface of the dirt floor concrete 20 .
However, the heating means 60 is not limited to floor heating equipment, and may be, for example, a heat pump air conditioner. Also, the floor heating equipment may be a method of heating a planar heating element arranged in the dirt floor concrete 20 without relying on the circulation of the heat medium 64 .

<8> Operation method of the solar power generation system in the agricultural house The solar power generation system 1 in the agricultural house of the present invention is a combination of the dirt floor concrete 20, the solar power generation surface material 40, and the heating means 60. It is possible to achieve both yield and high power generation efficiency.
The in-house photovoltaic power generation system 1 for agriculture is operated, for example, as follows.

<8.1> Cold period (Fig. 5A)
In the cold season of winter, the total amount or most of the power generated by the solar power generation surface material 40 is used to operate the heating means 60, and the temperature in the house space S is increased by the radiant heat of the heating means 60 and the dirt floor concrete 20. , and maintained at 15-20° C. suitable for growing the crop 32 .
In addition, when the power generation amount of the solar power generation surface material 40 is not sufficient, in addition to the power generation amount of the solar power generation surface material 40, electric power may be additionally supplied from the outside.
In the cold season, the growth of crops 32 is suppressed due to shortened sunshine hours, so the leaf area of crops 32 is reduced. Therefore, the amount of light received by the photovoltaic power generation surface material 40 increases by reducing the area where the leaves of the crops 32 block the light, thereby making it possible to compensate for the decrease in the amount of power generated due to the shortened sunshine hours.
In addition, even if there is snowfall, the temperature in the house space S is always maintained at about 15 to 20 ° C. by the radiant heat of the heating means 60 and the earth floor concrete 20, so that the coating 12 of the house body 10 Snow adhering to the house body 10 can be prevented from accumulating on the house body 10 by immediately melting the snow adhering to the house body 10.例文帳に追加As a result, even in a snowy area, the photovoltaic surface material 40 can always secure sunlight, and a reduction in the amount of power generated can be avoided.

<8.2> Warm period (Fig. 5B)
During the warm season including spring and autumn, part of the power generated by the solar power generation surface material 40 is used to operate the heating means 60, and the radiant heat of the heating means 60 and the dirt floor concrete 20 heats the inside of the house space S. The air temperature is maintained at 15-20° C. suitable for growing crops 32 .
During the warm season, the hours of sunshine are longer than in the cold season, and the amount of power generated by the photovoltaic power generation surface material 40 is increased.
Therefore, of the amount of power generated by the photovoltaic power generation surface material 40, the remaining amount that is not used for the heating means 60 can be transmitted to the external power grid G via the power transmission means 70 and used for selling power or self-consignment. can.

<8.3> Hot season (Fig. 5C)
In the hot season from July to August, the sunshine hours are the longest, the outside temperature rises, and the temperature inside the house space S becomes extremely high.
Therefore, during this period, the cultivation facility 30 is removed from the greenhouse space S, the entire agricultural greenhouse is used as a complete power generation facility, and the total amount of power generated is transmitted to the external power transmission network G and sold or self-consigned. can be used for
In the hot season, strong sunlight directly hits the photovoltaic power generation surface material 40, but the temperature of the photovoltaic power generation surface material 40 rises by transferring heat from the lower surface of the photovoltaic power generation surface material 40 to the inside of the dirt floor concrete 20. It is possible to avoid a decrease in power generation efficiency due to
In addition, a method of using a water supply pipe for the cultivation facility 30 to sprinkle water on the surface of the heated photovoltaic power generation surface material 40 and the earth floor concrete 20, and a method of circulating water in the heat transfer pipe 63 of the heating means 60 By the method of recovering the heat in the concrete 20, the surface temperature of the photovoltaic power generation surface material 40 can be lowered to maintain the power generation efficiency.

1 Photovoltaic Power Generation System in an Agricultural House 10 House Body 11 Frame 12 Coating 13 Lighting Equipment 20 Earth Floor Concrete 21 Installation Ditch 22 Tension Material 30 Cultivation Equipment 30a Cultivation Equipment Array 31 Planter 32 Crop 40 Solar Power Generation Surface Material 40a Solar Power Generation Surface Material array 50 transformer means 60 heating means 61 storage battery 62 heat pump water heater 63 heat transfer pipe 64 heat medium 70 power transmission means
80 Thermal insulation 90 Moisture-proof film S House space G External transmission network

Claims (5)

a house body having a frame erected on the ground and a translucent coating covering the frame to define a house space;
Dirt floor concrete installed on the floor surface of the greenhouse space;
a cultivation facility that can be installed in the greenhouse space;
a photovoltaic face material arranged in contact with the upper surface of the earth floor concrete;
a transformer capable of converting DC power generated by the photovoltaic face material into AC;
a heating means capable of heating the air in the house space;
a plurality of power transmission means electrically connecting the photovoltaic surface material and the power transformation means, the power transformation means and the heating means, and the power transformation means and an external power grid, respectively;
At least part of the total power generation can be selectively transmitted to the external power grid,
A solar power generation system in a greenhouse for agriculture. The earth floor concrete has an installation groove, the solar power generation surface material is installed in the installation groove, and the surface of the earth floor concrete and the surface of the solar power generation surface material are flush with each other. The in-house photovoltaic power generation system for agriculture according to claim 1 . The heating means is a floor heating facility that heats a heat medium and circulates the heat medium in a heat transfer pipe arranged in the earth floor concrete to heat the earth floor concrete. 3. The in-house photovoltaic power generation system for agriculture according to 1 or 2. A plurality of the cultivation facilities are arranged along the longitudinal direction of the house body to constitute a cultivation facility array, and a plurality of the solar power generation surface materials are arranged along the cultivation facility array to form a solar power generation surface material array. and the cultivation equipment array is sandwiched between adjacent solar power generation surface material arrays. power generation system. 5. The agricultural house indoor sun according to any one of claims 1 to 4, characterized by comprising a heat insulating material installed on the lower surface of the earth floor concrete and a moisture-proof film laid on the lower surface of the heat insulating material. photovoltaic system.