JP2012029688A - Apparatus and method for supplying carbon dioxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for sufficiently supplying carbon dioxide semi-persistently and even in a summer season to a carbon dioxide-using chamber using carbon dioxide, such as a plastic greenhouse.SOLUTION: The apparatus for supplying carbon dioxide is such that an intake/exhaust agent 2 causing equilibrium reaction involving intake/exhaust of carbon dioxide is arranged within a blowing path of blowing means 30. The apparatus includes in a first mode, sending open air by the blowing means 30 from a first opening 91 into a carbon dioxide-using chamber 90, and sending out ambient gas in the carbon dioxide-using chamber 90 from a second opening 91, and in a second mode, sending open air by the blowing means 30 from the second opening 92 into the carbon dioxide-using chamber 90, and sending out ambient gas in the carbon dioxide-using chamber 90 from the first opening 91, and alternately repeatedly performing the first mode and the second mode.

Description

  The present invention relates to an apparatus and a method for supplying carbon dioxide into a carbon dioxide using room such as a greenhouse for agriculture and horticulture.

  A greenhouse is known as a greenhouse where plants are grown. The inside of the greenhouse can be a sealed space that is almost isolated from the outside world. However, if the airtightness is high, the carbon dioxide concentration decreases as the crop grows, and the growth reaches its peak. Therefore, carbon dioxide was artificially added (applied) by installing a carbon dioxide cylinder, installing dry ice, or burning fossil fuels such as kerosene.

In Patent Document 1, in order to cultivate a plant in an open place, a carbon dioxide-containing solution is generated by applying a voltage by immersing a pair of carbon electrodes in water, and supplying the carbon dioxide-containing solution to the plant. Yes.
In patent document 2, carbonated water is produced | generated with the carbon dioxide gas and water which were supplied from the carbon dioxide cylinder, and this carbonated water is sprayed on the plant in a house.

Japanese Patent Application Laid-Open No. 08-84529 JP 2008-199920 A

  None of the conventional carbon dioxide supply means can be operated permanently unless the carbon dioxide raw material is periodically replenished. For example, when a carbon dioxide cylinder is used, it is necessary to replenish carbon dioxide in the cylinder or replace the cylinder when the inside of the cylinder is empty. In the case of using dry ice, it was necessary to replenish new dry ice when the dry ice vaporized and disappeared. When burning fossil fuels such as kerosene, it was necessary to replenish when the fuel was exhausted. In patent document 1, when a carbon electrode melt | dissolves, it is thought that it needs to replace | exchange.

Moreover, since the sunlight is strong in summer, plant growth can be greatly promoted if the carbon dioxide concentration in the greenhouse can be increased. However, since the greenhouse usually ventilates the interior by opening a ventilation window in the summer, carbon dioxide supplied from the carbon dioxide supply means escapes outside. In the case of burning fossil fuel such as kerosene, the temperature in the greenhouse becomes too high, so it is not suitable for summer use. Therefore, in spite of the expected growth of plants in the summer, conventional carbon dioxide supply means cannot sufficiently respond to this.
In view of the above circumstances, the present invention is a technology that can be supplied semi-permanently without supplementing carbon dioxide in a carbon dioxide utilization room that uses carbon dioxide such as a greenhouse, and is also suitable for operation in summer. Is to provide.

In view of the above circumstances, the apparatus of the present invention is an apparatus for supplying carbon dioxide to a carbon dioxide utilization chamber having a first opening and a second opening,
An adsorbent / release agent that causes an equilibrium reaction with absorption / release of carbon dioxide, an air blowing means that forms an air flow path through the first opening, the inside of the carbon oxide utilization chamber, and the second opening; Switching means for alternately switching between the first mode and the second mode between the sucking and releasing and the blowing mode of the blowing means, and the absorbing and releasing agent is disposed on the blowing path of the blowing means, In the first mode, the air blowing means sends outside air into the carbon dioxide using chamber from the first opening, and sends atmospheric gas in the carbon dioxide using chamber from the second opening. In the second mode, the blowing means sends outside air into the carbon dioxide utilization chamber from the second opening and sends out the atmospheric gas from the first opening.

  In any of the first and second modes, the outside air can contact the absorption / release agent to release carbon dioxide from the absorption / release agent and supply the carbon dioxide to the carbon dioxide utilization chamber. On the other hand, when the atmospheric gas in the carbon dioxide utilization chamber comes into contact with the absorbent, the carbon dioxide in the atmospheric gas can be absorbed by the absorbent and recovered. By repeating the first mode and the second mode, the absorption / release agent repeats the release and absorption of carbon dioxide. Thus, carbon dioxide can be supplied to the carbon dioxide utilization room over a long period of time or semipermanently. Since the absorption / release agent absorbs carbon dioxide from the air and releases the carbon dioxide, it can be said that carbon dioxide in the air is a carbon dioxide raw material. Therefore, it is not necessary to periodically replenish special carbon dioxide materials such as carbon dioxide cylinders, dry ice, fossil fuels, and carbon electrodes. Therefore, maintenance and management are easy, and running costs can be suppressed. In addition, carbon dioxide can be supplied to the carbon dioxide utilization chamber while ventilating the carbon dioxide utilization chamber by blowing air from the blowing means. Therefore, it is suitable for summer driving. When the carbon dioxide utilization room is for growing plants such as a greenhouse, the growth of plants can be sufficiently promoted in combination with the intensity of sunlight in summer.

  Here, the carbon dioxide utilization room refers to a room that uses carbon dioxide to grow plants, culture / proliferate living organisms and living tissues, and preserve / store / treat / observe living organisms and substances. It includes a greenhouse (green house) for plant growth in horticulture, a fermentation room, a brewing room, a storage room, a storage room, etc. The greenhouse refers to a facility capable of maintaining the room at an appropriate temperature, and includes, for example, a plastic house and a constant temperature room. A greenhouse refers to a facility in which the room is surrounded by a light-transmitting sheet, and the room temperature, humidity, lighting degree, etc. are made suitable for the cultivation of crops and the like. The material of the translucent sheet is, for example, a vinyl resin, but is not limited thereto, and may be a resin other than a vinyl resin, for example, an olefin-based resin such as polyethylene, and is not limited to a flexible film, and is hard. A transparent plate-like resin or glass may be used. The translucent sheet is not limited to being transparent and may be translucent. A part of the outer periphery of the greenhouse may be made of a material that does not have translucency. The greenhouse may be a dark room.

  The absorption / release agent preferably causes an equilibrium reaction involving absorption / release of carbon dioxide and water vapor. That is, it is preferable that the absorption / release agent not only absorbs / releases carbon dioxide but also absorbs / releases water vapor. As a result, the absorbent absorbs and releases carbon dioxide according to the humidity of the outside air (water vapor partial pressure) sent to the carbon dioxide utilization chamber and the humidity of the atmospheric gas (water vapor partial pressure) sent from the carbon dioxide utilization chamber. You can do that.

  Examples of the substance that causes the equilibrium reaction include alkali metal carbonates, ammonium carbonates, amine compound carbonates, and hydrates thereof. The absorption / release agent preferably contains at least one of these substances. Examples of the alkali metal carbonate include alkali metal carbonates such as potassium carbonate, sodium carbonate, and lithium carbonate, and alkali metal sesqui carbonates such as potassium sesquicarbonate, sodium sesquicarbonate, and lithium sesquicarbonate. These carbonates or hydrates thereof coexist in equilibrium with the bicarbonate. For example, potassium carbonate or potassium carbonate hydrate is in equilibrium with potassium bicarbonate. Sodium carbonate or sodium carbonate hydrate is in equilibrium with sodium bicarbonate. Lithium carbonate or lithium carbonate hydrate coexists in equilibrium with lithium hydrogen carbonate. Ammonium carbonate (ammonium carbonate) or ammonium carbonate hydrate coexists in equilibrium with ammonium bicarbonate. The amine carbonate compound (amine compound carbonate) or hydrate thereof coexists in equilibrium with the hydrogen carbonate amine compound. Since amine is easily gasified or liquefied and unstable, it may be fixed by being bonded to the carbon chain of the polymer. As a component of the absorption / release agent, a polymer having a fixed amine carbonate group or a hydrate thereof may be used. Polystyrene is preferred as the polymer.

  It is preferable that the absorption / release agent absorbs water vapor when absorbing carbon dioxide and also releases water vapor when releasing carbon dioxide. Examples of such a substance include equilibrium coexisting substances of the above-mentioned various carbonates and hydrogencarbonates thereof. The absorption / release agent is an equilibrium coexisting substance of potassium carbonate and potassium hydrogen carbonate, an equilibrium coexisting substance of sodium carbonate and sodium hydrogen carbonate, an equilibrium coexisting substance of lithium carbonate and lithium hydrogen carbonate, ammonium carbonate and ammonium hydrogen carbonate. It is preferable to include an equilibrium coexisting substance, an equilibrium coexisting substance of an amine carbonate compound and a hydrogen carbonate amine compound, or a polymer such as polystyrene in which an amine carbonate group and an hydrogen carbonate amine group are fixed to a carbon chain in an equilibrium coexistence state. Accordingly, when the water vapor partial pressure (humidity) of the atmospheric gas in the carbon dioxide utilization chamber is made higher than the water vapor partial pressure (humidity) of the outside air, the carbon dioxide concentration in the carbon dioxide utilization chamber is automatically set from the carbon dioxide concentration in the outside air. Can be kept high. For example, when the carbon dioxide utilization room is a greenhouse such as a greenhouse, the room usually has a higher humidity than the outside air. When contacted, the absorption / release agent releases moisture and also releases carbon dioxide. As a result, the carbon dioxide concentration in the room can be made higher than the carbon dioxide concentration in the outside air. Moreover, when the indoor gas having a relatively high humidity is sent out of the room while being in contact with the absorption / release agent, the absorption / release agent absorbs moisture from the atmospheric gas and also absorbs carbon dioxide. Thereby, carbon dioxide can be recovered.

  The absorption / release agent may release water vapor when absorbing carbon dioxide and absorb water vapor when releasing carbon dioxide. Examples of such substances include equilibrium coexisting substances of the above-mentioned various carbonate hydrates and their hydrogen carbonates. The absorbing / releasing agent is an equilibrium coexisting substance of potassium carbonate hydrate and potassium hydrogen carbonate, an equilibrium coexisting substance of sodium carbonate hydrate and sodium hydrogen carbonate, an equilibrium coexisting substance of lithium carbonate hydrate and lithium hydrogen carbonate. In addition, an equilibrium coexisting substance of ammonium carbonate hydrate and ammonium hydrogencarbonate, an equilibrium coexisting substance of a hydrate of an amine carbonate compound and an amine hydrogencarbonate compound, or a hydrate of the polymer may be included. The absorption / release agent in this case is suitable for use under conditions where the humidity in the carbon dioxide utilization room is lower than the humidity of the outside air. For example, it is suitable for growing a crop suitable for a dry environment in a humid area. That is, when outside air of relatively high humidity is sent into the carbon dioxide utilization chamber and brought into contact with the absorption / release agent, the absorption / release agent absorbs moisture from the input gas and releases carbon dioxide. As a result, the carbon dioxide concentration in the room can be kept higher than the carbon dioxide concentration in the outside air. Further, when the indoor gas having a relatively low humidity is sent out of the room while being in contact with the absorption / release agent, the absorption / release agent releases moisture and absorbs carbon dioxide. Thereby, carbon dioxide can be recovered.

  The absorption / release agent may contain a hygroscopic substance. The absorption / release agent may further contain a hygroscopic substance in addition to the various carbonates. Specifically, the absorption / release agent is a potassium carbonate, sodium carbonate, lithium carbonate, sesquipotassium carbonate, sodium sesquicarbonate, lithium sesquicarbonate, ammonium carbonate, an amine carbonate compound, or a polymer in which an amine carbonate group is fixed. In addition, a hygroscopic substance may be further contained. In this case, it is preferable that the various carbonates or the polymer constitutes a hydrate. The hydrates of the various carbonates preferably exist in equilibrium with the hydrogen carbonate, and the amine carbonate group of the polymer preferably exists in equilibrium with the hydrogen carbonate amine group. Accordingly, when the absorption / release agent absorbs carbon dioxide, water vapor is also absorbed, and when carbon dioxide is released, water vapor is also released. Therefore, when the atmospheric gas in the carbon dioxide utilization chamber has a higher humidity than the outside air, the carbon dioxide concentration of the atmospheric gas can be naturally higher than the carbon dioxide concentration in the outside air. Examples of the hygroscopic substance include lime and silica gel.

A first suction / release means provided in the first opening so as to allow ventilation; and a second suction / release means provided in the second opening so as to allow ventilation, wherein the first and second suction / release means are respectively provided. It is preferable to contain the said absorption / release agent.
As a result, in the first mode, when the outside air contacts the first absorption / release means, carbon dioxide can be released from the first absorption / release means, and this carbon dioxide can be supplied to the carbon dioxide utilization chamber. When the atmospheric gas in the utilization chamber comes into contact with the second absorption / release means, carbon dioxide in the atmospheric gas can be absorbed by the second absorption / release means. In the second mode, when outside air comes into contact with the second absorption / release means, carbon dioxide can be released from the second absorption / release means, and this carbon dioxide can be supplied to the carbon dioxide utilization chamber. When the atmospheric gas comes into contact with the first absorption / release means, carbon dioxide in the atmospheric gas can be absorbed by the first absorption / release means. By alternately repeating the first mode and the second mode, the first and second absorption / release means repeat the release and absorption of carbon dioxide, respectively. As a result, carbon dioxide can be reliably supplied to the carbon dioxide utilization chamber over a long period of time or semipermanently.

The first or second absorbing / releasing means includes a plurality of absorbing / releasing members containing the absorbing / releasing agent arranged in parallel with each other, and a gap between adjacent absorbing / releasing members forms part of the air blowing path. It is preferable.
Thereby, the flow of the outside air or the atmospheric gas can be surely brought into contact with the absorption / release member, and the absorption / release of carbon dioxide can be surely caused.
The first or second absorbing / releasing member is not limited to a flat plate shape, and may be a lattice shape or a porous body. The lattice-shaped first or second absorbing / releasing member may be a honeycomb (hexagonal lattice) structure, a square lattice structure, or a triangular lattice structure.

The absorption / release member may contain a binder that binds the absorption / release agent.
Thereby, even if the absorption / release agent is in a powder form, it can be solidified.

The absorption / release member includes a frame having a space in the frame and a pair of breathable covers stretched on both surfaces of the frame so as to cover the space in the frame, and the absorption / release agent is in a powder state And may be housed in the space in the frame.
The adsorbent / release agent powder can be confined in the space in the frame by the frame and the pair of covers. Outside air and atmospheric gas can pass through the breathable cover and come into contact with the absorbent / release agent powder in the space inside the frame. This makes it possible to reliably cause the carbon dioxide absorption / release reaction by the absorption / release agent powder. Carbon dioxide released from the absorbent / release agent powder passes through the breathable cover and is supplied to the carbon dioxide utilization chamber.

The air blowing means is provided in the first opening to perform the outside air feeding in the first mode, and the second air blowing is provided in the second opening to perform the outside air feeding in the second mode. It is preferable that a part is included.
In the first mode, the outside air can be reliably sent into the carbon dioxide using room through the first opening by the first blower. In the second mode, the outside air can be reliably sent into the carbon dioxide using room through the second opening by the second air blowing section.
The 1st, 2nd ventilation part is comprised by the fan, the blower, etc., for example.

The carbon dioxide supply device may further include a carbon dioxide supplementing unit. The carbon dioxide replenishing means includes a container containing a second absorption / release agent, a suction pump for sucking gas inside the container, and a replenishment path connecting the exhaust port of the suction pump to the inside of the carbon dioxide utilization chamber. Are preferably included.
In general, when the partial pressure of carbon dioxide increases, the equilibrium moves in the direction of absorbing carbon dioxide, and the equilibrium moves in the direction of releasing carbon dioxide when the partial pressure of carbon dioxide decreases. Therefore, when the carbon dioxide concentration in the carbon dioxide utilization chamber decreases, the gas inside the container is sucked by the suction pump. Then, the internal pressure of the container decreases, and carbon dioxide is released from the second absorption / release agent. By sending the gas in the container containing carbon dioxide to the carbon dioxide utilization chamber through the replenishment path, the carbon dioxide utilization chamber can be supplemented. As a result, the carbon dioxide concentration in the carbon dioxide utilization chamber can be further reliably increased. The second absorption / release agent is preferably in the form of powder.

The inside of the container is preferably openable and sealable to the outside, and more preferably the degree of opening to the outside can be adjusted. The container is preferably provided with an open path (or opening) that opens the inside to the outside. The open path is preferably openable / closable, and more preferably adjustable in opening.
During the period when the suction pump is stopped, the outside of the container is opened to the outside, so that outside air enters the inside of the container. The carbon dioxide in the outside air can be absorbed by the second absorption / release agent. Therefore, the outside air can be used as a carbon dioxide raw material, and the carbon dioxide replenishing means can be operated for a long time or semi-permanently without using a special carbon dioxide raw material such as a carbon dioxide cylinder.

The carbon dioxide replenishing means may be provided with an air supply means for sending air into the container. During the period when the suction pump is stopped, the second air-absorbing / releasing agent can absorb carbon dioxide in the air by feeding air into the container by the air feeding means. When driving the air supply means, it is preferable to open the open path and open the inside of the container. As a result, air from the air supply means flows through the inside of the container and is then discharged from the open path. The interior of the container is maintained at approximately atmospheric pressure. The total flow rate of the air from the air supply means in terms of atmospheric pressure can be made equal to or greater than the inner volume of the container, and the second absorbent / release agent can sufficiently absorb carbon dioxide.
The air supply means may be an air supply pump, a blower fan, or a blower.
A pressure pump may be used as the air feeding means, and the outside air may be compressed and fed into the container with the pressure feeding pump while the open path is closed and the inside of the container is sealed.
When the suction pump is operated, that is, when carbon dioxide is replenished to the carbon dioxide utilization chamber, the air supply means is stopped.

The suction pump may be a diaphragm type vacuum pump, a scroll type vacuum pump, or a reciprocating type vacuum pump.
The container may be sealed when the suction pump is operated.
When the vacuum level of the suction pump is small, such as a diaphragm vacuum pump, the suction pump may be driven with the open path half open. Thus, the carbon dioxide-containing gas in the container can be reliably sucked and supplied to the carbon dioxide utilization chamber. During the stop period of the suction pump, the opening degree of the open path may be relatively increased, and during the driving of the suction pump, the opening degree of the open path may be relatively decreased.

A method according to the present invention is a method of supplying carbon dioxide to a carbon dioxide utilization chamber having a first opening and a second opening,
An absorption / release agent that causes an equilibrium reaction with absorption / release of carbon dioxide is placed on the blowing path of the blowing means,
A first step of sending outside air from the first opening to the inside of the carbon dioxide utilization chamber by the blowing means, and sending atmospheric gas in the carbon dioxide utilization chamber from the second opening;
A second step of sending outside air from the second opening to the inside of the carbon dioxide using chamber by the blowing means, and sending atmospheric gas in the carbon dioxide using chamber from the first opening;
Is performed alternately and repeatedly.

  In any one of the first and second steps, the outside air comes into contact with the absorption / release agent to release carbon dioxide from the absorption / release agent, and this carbon dioxide can be supplied to the carbon dioxide utilization chamber. In the other of the first and second steps, the carbon dioxide in the atmospheric gas can be absorbed by the absorption / release agent by contacting the atmospheric gas in the carbon dioxide utilization chamber with the absorption / release agent. By repeating the first step and the second step, the absorption / release agent repeats the release and absorption of carbon dioxide. As a result, carbon dioxide can be supplied to the carbon dioxide utilization room for a long time or semi-permanently. Since the absorption / release agent absorbs carbon dioxide from the air and releases the carbon dioxide, it can be said that carbon dioxide in the air is a carbon dioxide raw material. Therefore, it is not necessary to periodically replenish special carbon dioxide materials such as carbon dioxide cylinders, dry ice, fossil fuels, and carbon electrodes. Therefore, maintenance and management are easy, and running costs can be suppressed. In addition, carbon dioxide can be supplied to the carbon dioxide utilization chamber while ventilating the carbon dioxide utilization chamber by blowing air from the blowing means. Therefore, it is suitable for summer driving. When the carbon dioxide utilization room is for growing plants such as a greenhouse, the growth of plants can be sufficiently promoted in combination with the intensity of sunlight in summer.

When the integrated air flow rate in each of the first and second steps becomes substantially the same as the internal volume of the carbon dioxide utilization chamber, the first and second steps are performed immediately or after a pause step in which the blowing means is suspended. May be switched.
By executing the first and second steps, the gas in the carbon dioxide utilization chamber can be substantially replaced. This makes it possible to supply carbon dioxide to the carbon dioxide utilization chamber while reliably ventilating the carbon dioxide utilization chamber.

A replenishment preparation step of bringing air into contact with the second absorption / release agent accommodated in the container, and a replenishment step of sucking the gas inside the container with a suction pump and supplying the gas inside the carbon dioxide utilization chamber, It is preferable that the first and second steps are alternately performed separately.
Through the replenishment preparation step, carbon dioxide in the air can be absorbed by the second absorption / release agent in the container. In the replenishment preparation step, air may be sent into the container by an air supply pump. At this time, the inside of the container may be opened to the outside, and the air after distribution may be discharged. A replenishment step is performed when the carbon dioxide concentration in the carbon dioxide utilization chamber decreases. Thereby, carbon dioxide is released from the second absorbent / release agent, and the gas in the container containing the carbon dioxide is supplied to the carbon dioxide utilization chamber through the replenishment path. Thereby, carbon dioxide can be replenished to the carbon dioxide utilization room. As a result, the carbon dioxide concentration in the carbon dioxide utilization chamber can be further reliably increased. After performing the replenishment step, the carbon dioxide utilization chamber can be prepared for carbon dioxide replenishment by performing the replenishment preparation step again. The second absorption / release agent is preferably in the form of powder.

  According to the present invention, carbon dioxide can be supplied for a long time or semi-permanently to a carbon dioxide utilization room such as a greenhouse. Moreover, since carbon dioxide can be supplied while ventilating the carbon dioxide room, it is suitable for summer driving.

1 is a perspective view showing a first embodiment of the present invention. Be a graph showing calculated values of KHCO ₃ molar abundance of α with respect to CO ₂ partial pressure in the atmospheric gas at the time of KHCO ₃ and absorbing polishes consisting equilibrium coexistence of _K 2 CO ₃ is in equilibrium at a temperature 30 ° C. The solid line represents the relative humidity of 80%, the alternate long and short dash line represents the relative humidity of 50%, and the broken line represents the relative humidity of 10%. It is a perspective view which shows 2nd Embodiment of this invention. It is a perspective view which shows 3rd Embodiment of this invention. It is a perspective view which shows 4th Embodiment of this invention. It is a perspective view which shows 5th Embodiment of this invention. It is a perspective view which shows 6th Embodiment of this invention. It is a perspective view which shows 7th Embodiment of this invention. It is a perspective view of the absorption / release member having a honeycomb structure, showing a modification of the absorption / release member. It is a perspective view of the absorption / release member having a square lattice structure, showing a modification of the absorption / release member. It is a perspective view which shows the modification of an absorption / release member. It is sectional drawing of the absorption-and-release member along the Xb-Xb line | wire of Fig.10 (a).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The present invention is applied to supply or replenish carbon dioxide to a carbon dioxide utilization chamber that utilizes or requires carbon dioxide. The carbon dioxide utilization chamber is preferably a semi-closed system in which the inside can be substantially isolated from the outside. FIG. 1 shows a first embodiment in which the present invention is applied to a greenhouse 90 (carbon dioxide utilization room) for growing plants S. The plant S is not particularly limited, and may be an agricultural crop or a horticultural crop. First and second openings 91 and 92 are formed in the greenhouse 90. The first opening 91 and the second opening 92 are separated from each other in the direction of the greenhouse 90. The first opening 91 is disposed on the end face (left side in FIG. 1) of the greenhouse 90. The 2nd opening 92 is arrange | positioned at the wife face of the other end side (right in FIG. 1) of the greenhouse 90. As shown in FIG. Existing ventilation openings of the greenhouse 90 may be applied as the openings 91 and 92.

Usually, _{H 2} O partial pressure in the vinyl house 90 (humidity) is higher than the outside air _{H 2} O partial pressure (humidity). In general, the CO ₂ concentration in the outside air is about 350 ppm to 380 ppm, and the CO ₂ partial pressure is about 35 Pa to 38 Pa.

  The greenhouse 90 is equipped with a carbon dioxide supply device 1. The carbon dioxide supply device 1 includes first and second absorption / release means 10 and 20 and a blowing means 30. The first suction / release means 10 is provided in the first opening 91 of the greenhouse 90. The second suction / release means 20 is provided in the second opening 92 of the greenhouse 90.

  The first sucking / releasing means 10 is a unit including a plurality of sucking / releasing members 11 and a support fixing portion (not shown) that supports the sucking / releasing members 11 and is fixed to the greenhouse 90. Each absorption / release member 11 has a plate shape. The shape of the absorbing / releasing member 11 is, for example, a substantially square of 1 m square, but is not limited thereto, and may be, for example, a vertically long or horizontally long rectangle, and is not limited to a flat plate shape, and may be curved. . The thickness of the absorption / release member 11 is about 1 mm, but is not limited thereto. Each absorption / release member 11 is disposed so as to be orthogonal to (intersect) the left wife surface of the greenhouse 90. Although the suction / release member 11 is oriented vertically, it may be horizontal or may be inclined vertically or horizontally. The plurality of absorption / release members 11 are arranged in parallel at intervals in the width direction of the first opening 91. The arrangement interval of the absorption / release members 11 is, for example, about 2 mm to 10 mm, but is not limited thereto.

  The first suction / release means 10 can be ventilated. That is, the outside air can enter the greenhouse 90 through the gap 12 between the adjacent absorption / release members 11. In addition, the atmospheric gas in the greenhouse 90 can flow out through the gap 12 between the absorption / release members 11.

  The second sucking / releasing means 20 is a unit including a plurality of second sucking / releasing members 21 and a support fixing portion (not shown) that supports these sucking / releasing members 21 and is fixed to the greenhouse 90. . The number, shape, size, and arrangement interval of the second absorption / release members 21 are the same as those of the first absorption / release member 11, but may be different from those of the first absorption / release member 11. Each of the suction / release members 21 is arranged so as to be orthogonal (cross) to the right wife surface of the greenhouse 90. Although the suction / release member 21 is oriented vertically, it may be horizontal or may be inclined vertically or horizontally. The plurality of absorption / release members 21 are arranged in parallel at intervals in the width direction of the second opening 92.

  The second suction / release means 20 can be ventilated. That is, outside air can enter the greenhouse 90 through the gap 22 between the adjacent absorption / release members 21. In addition, the atmospheric gas in the greenhouse 90 can flow out through the gap 22 between the absorption / release members 21.

  The component configurations of the first and second absorption / release members 11 and 21 are the same. The absorption / release members 11, 21 contain the absorption / release agent 2 and a binder. The normal form of the absorption / release agent 2 is powdery. The plate-like absorption / release members 11 and 21 are configured by kneading and binding the powder-like absorption / release agent 2 with a binder. As the binder, a resin such as polytetrafluoroethylene (PTFE) can be used. The weight ratio of the absorbent / release agent 2 and the binder is, for example, 1: 1 to 10: 1, but is not limited thereto.

The absorption / release agent 2 contains potassium hydrogen carbonate (KHCO ₃ ) as a main component. KHCO ₃ causes an equilibrium reaction of the following formula and coexists with potassium carbonate (K ₂ CO ₃ ).
K ₂ CO ₃ + H ₂ O + CO ₂ ⇔ 2KHCO ₃ (Formula 1)
Part of the absorbent / release agent 2 is composed of K ₂ CO ₃ . The absorbent / release agent 2 is an equilibrium coexistent of KHCO ₃ and K ₂ CO ₃ . The equilibrium reaction of KHCO ₃ and K ₂ CO ₃ is accompanied by absorption / release of CO ₂ , and further, absorption / release of H ₂ O. When the absorbent / release agent 2 absorbs CO ₂ , it also absorbs H ₂ O. When the absorbent / release agent 2 releases CO ₂ , H ₂ O is also released at the same time. The ratio of KHCO ₃ and K ₂ CO _{3 in} the absorbent / release agent 2 varies according to the CO ₂ partial pressure, H ₂ O partial pressure, temperature, pressure, and the like of the arrangement environment of the absorbent / release agent 2. The molar abundance α of KHCO ₃ with respect to the total number of moles of KHCO ₃ and K ₂ CO ₃ in the absorbent / release agent 2 is defined by the following equation.

Hereinafter, the molar abundance ratio α of KHCO ₃ of the absorption / release agent 2 constituting the absorption / release member 11 is expressed as α1. The molar abundance α of KHCO _{3 in} the absorption / release agent 2 constituting the absorption / release member 21 is expressed as α2. The molar abundance α of KHCO _{3 in} an equilibrium state when the absorbent / release agent 2 is placed in the outside air (air) is expressed as α0. The KHCO ₃ molar abundance α1, α2 of the first and second absorbing / releasing members 11, 21 is preferably at least larger than the equilibrium value α0 in the atmosphere (α1> α0, α2> α0). The KHCO ₃ molar abundance ratio α of the adsorbent / release agent 2 when the H ₂ O partial pressure is equal to that in the house 90 and the CO ₂ partial pressure is equal to that in the outside air is αA (see FIG. 2). KHCO ₃ molar abundance ratio α of the absorbent / release agent 2 when the H ₂ O partial pressure is equal to that in the outside air and the CO ₂ partial pressure is equal to the set partial pressure in the house 90 (equivalent to the set concentration described later). Is αB (see FIG. 2).

The carbon dioxide supply device 1 is preferably operated under the condition of αA> αB. Furthermore, the carbon dioxide supply device 1 is preferably operated such that, for example, a range of αB or more and αA or less is selected, and α1 and α2 each vary within the selection range (αA to αB). That is, it is preferable to operate so as to satisfy the following relationship.
αA ≧ α1 ≧ αB and αA ≧ α2 ≧ αB (Formula 3)
α1 and α2 may be varied within a range wider than the selection range (αA to αB), and may be varied within a range shifted from the selection range (αA to αB) toward the high rate side or the low rate side. You may do it.

  The blowing means 30 forms a blowing path that passes through the first opening 91, the inside of the greenhouse 90, and the second opening 92. The blowing unit 30 includes a first blowing unit 31 and a second blowing unit 32. These ventilation parts 31 and 32 are comprised with the fan. The first fan 31 is provided in the first opening 91. The fan 31 faces the end face of each of the suction / release members 11 of the first suction / release means 10 and faces the gap 12 between the suction / release members 11. In the drawing, the fan 31 is disposed on the outdoor side from the first suction / release means 10, but may be disposed on the indoor side of the greenhouse 90 from the first suction / release means 10. Due to the rotation of the fan 31, outside air passes through the first suction / release means 10 from the first opening 91 and is sent into the greenhouse 90. Pushed by the flow of the outside air, the atmospheric gas in the greenhouse 90 passes through the second suction / release means 20 and is sent out from the second opening 92.

  The second fan 32 is provided in the second opening 92. The fan 32 faces the end face of each of the suction / release members 21 of the second suction / release means 20 and faces the gap 22 between the suction / release members 21. In the figure, the fan 32 is disposed on the outdoor side from the second suction / release means 20, but may be disposed on the indoor side of the greenhouse 90 from the second suction / release means 20. Due to the rotation of the fan 32, outside air passes through the second suction / release means 20 from the second opening 92 and is sent into the greenhouse 90. Pushed by the flow of the outside air, the atmospheric gas in the greenhouse 90 passes through the first suction / release means 10 and is sent out from the first opening 91.

  Therefore, the suction / release means 10, 20 are arranged on the blowing path of the blowing means 30. A gap 12 between the absorbing / releasing members 11 of the first absorbing / releasing means 10 and a gap 22 between the absorbing / releasing members 21 of the second absorbing / releasing means 20 constitute a part of the blowing path of the blowing means 30.

The carbon dioxide supply device 1 further includes a controller 3. The controller 3 includes a CPU, a memory, an input / output interface, a driving circuit for the air blowing means 30, and the like. The controller 3 controls the operation of the blowing means 30. Specifically, the controller 3 selectively activates one of the first fan 31 and the second fan 32 and stops the other. As a result, the blowing direction of the blowing means 30 is selected, and either one of the absorption / release means 10 and 20 absorbs CO ₂ and the other of the absorption / release means 10 and 20 releases CO ₂ . Hereinafter, a period in which the air blowing means 30 operates so that the outside air is sent into the greenhouse 90 from the first opening 91 and the atmospheric gas in the greenhouse 90 is sent out from the second opening 92 to the outside is the first mode. The air blowing means 30 operates so that the outside air is sent into the greenhouse 90 from the second opening 92 and the atmospheric gas in the greenhouse 90 is sent to the outside through the first opening 91. This period is referred to as a second mode (second process). The controller 3 constitutes a switching unit that switches between the first mode and the second mode between the blowing mode of the blowing unit 30 and the absorption / release mode of the suction / release units 10 and 20.

In the memory of the controller 3, a time T for continuously executing the first and second modes is set. The set time T is, for example, a time when the integrated value of the air flow rate of the fans 31 and 32 is substantially equal to the internal volume of the greenhouse 90. That is, when the air flow rate per unit time of the fans 31 and 32 is Q and the internal volume of the greenhouse 90 is V, the mode duration T is set so that the following equation is established.
Q × T = V (Formula 4)
Therefore, if each of the first and second modes is continued for the time T, it can be considered that the entire gas in the greenhouse 90 is substantially replaced. Note that the set time T is not limited to a size that satisfies Equation 4, but may be T <(V / Q) or T> (V / Q).

  As a drive power source for the fans 31 and 32 and the controller 3 of the carbon dioxide supply device 1, it is preferable to use solar cells. As a result, it is possible to operate even in a place where commercial power cannot be supplied.

The operation of the carbon dioxide supply device 1 configured as described above will be described.
The carbon dioxide supply device 1 executes the first mode (first process) and the second mode (second process) alternately by the switching control of the switching means 3. Depending on the mode (process), either the first fan 31 or the second fan 32 is selectively operated. In the first mode, the outside air is sent into the house 90 through the first opening 91 and the first suction / release means 10, and the atmospheric gas in the house 90 is sent to the outdoors through the second suction / release means 20 and the second opening 92. . At this time, the first absorption / release member 11 releases CO ₂ and the second absorption / release member 21 absorbs CO ₂ in the delivery gas. In the second mode, the outside air is sent into the house 90 through the second opening 92 and the second suction / release means 20, and the atmospheric gas in the house 90 is sent to the outside through the first suction / release means 10 and the first opening 91. . At this time, the second absorption / release member 21 releases CO ₂ and the first absorption / release member 11 absorbs CO ₂ in the delivery gas.

The operation in each mode will be described in further detail. Now, it is assumed that the CO ₂ concentration in the greenhouse 90 is higher than the CO ₂ concentration in the outside air by the continuous operation of the carbon dioxide supply device 1. When the operation is started, the CO ₂ concentration in the greenhouse 90 can be set to a set concentration by other carbon dioxide supply means such as a CO ₂ cylinder. Further, it is assumed that Expression 3 is satisfied and that α90>αA≈α1>α2≈αB> α0. Here, α90 is the KHCO ₃ molar abundance α when the absorbent / release agent 2 reaches an equilibrium state under the atmospheric gas in the house 90. Under this condition, the carbon dioxide supply device 1 selects the first mode (first step).

[First mode (first step)]
In the first mode (first step), the first fan 31 is operated and the second fan 32 is stopped. Due to the rotation of the first fan 31, the outside air passes through the first opening 91, and further passes through the gap 12 between the absorption / release members 11, 11 of the first absorption / release means 10 and the outside of the absorption / release members 11 at both ends. It is sent into the house 90. This incoming gas contacts the first intake / discharge member 11.

In the first suction / release member 11, the KHCO ₃ abundance ratio α1 is sufficiently larger than the equilibrium value α0 in the outside air (α1> α0), so the KHCO ₃ is balanced in the direction in which the KHCO ₃ is converted to K ₂ CO ₃ (toward the left in Equation 1). Move. By this equilibrium reaction, CO ₂ is released from the absorption / release member 11. This CO ₂ is mixed with the incoming gas. This increases the CO ₂ concentration of the incoming gas. In the equilibrium reaction, H ₂ O is also released, but the H ₂ O content in the incoming gas is sufficiently large compared to the H ₂ O release amount even if the relative humidity is about 10%. Is unchanged. Therefore, only the CO ₂ partial pressure of the input gas increases while maintaining the H ₂ O partial pressure which is substantially the same as that of the outdoors. The KHCO ₃ abundance ratio α1 of the suction / release member 11 is larger than the equilibrium value αB when the H ₂ O partial pressure is equal to the outside air and the CO ₂ partial pressure is equal to the set partial pressure in the house 90 (α1> αB). The suction / release member 11 can release CO ₂ until the CO ₂ concentration of the feed gas becomes equal to or higher than the set concentration. Therefore, a feed gas having a CO ₂ concentration equal to or higher than the set concentration can be supplied into the house 90. The KHCO ₃ abundance ratio α1 of the absorption / release member 11 decreases with the release of CO ₂ .

  Further, the atmospheric gas in the greenhouse 90 is pushed by the flow of the outside air, and passes through the gap 22 between the suction / release members 21 and 21 of the second suction / release means 20 and the outside of the suction / release members 21 at both ends. Then, it is sent to the outside through the second opening 92. This delivery gas comes into contact with the second suction / release member 21.

In the second absorption / release member 21, since the KHCO ₃ abundance ratio α2 is smaller than the in-house equilibrium value α90 (α2 <α90), the equilibrium is maintained in the direction in which K ₂ CO ₃ is converted to KHCO ₃ (rightward in Expression 1). Moving. By this equilibrium reaction, the absorption / release member 21 absorbs CO ₂ in the delivery gas. This reduces the CO ₂ concentration of the delivery gas. In the equilibrium reaction, H ₂ O is also absorbed, but the H ₂ O content in the delivery gas is substantially unchanged since it is sufficiently larger than the H ₂ O absorption. Therefore, only the CO ₂ partial pressure of the delivery gas is reduced while maintaining the same H ₂ O partial pressure as in the house 90. The KHCO ₃ abundance ratio α2 of the suction / release member 21 is smaller than the equilibrium value αA (α2 <αA) when the H ₂ O partial pressure is equal to that in the house 90 and the CO ₂ partial pressure is equal to the outside air (α2 <αA). Until the CO ₂ concentration becomes lower, the absorption / release member 21 can absorb CO ₂ from the delivery gas. Thus, the delivery gas is discharged outdoors with a lower CO ₂ concentration than the outside air. The KHCO ₃ existence ratio α2 of the absorption / release member 21 increases with the absorption of CO ₂ . By continuing the first mode, α2> α1 is eventually satisfied. Furthermore, αA≈α2> α1≈αB is approached.

  The switching means 3 determines the mode switching timing. When the switching timing is reached, the first mode is switched to the second mode. For example, the switching unit 3 counts the duration of the first mode and determines whether the duration has reached the set time T. That is, it is determined whether or not the integrated air flow rate Q × T in the first mode is substantially the same as the internal volume V of the greenhouse 90 (Formula 4). The switching means 3 switches from the first mode to the second mode when the duration time of the first mode reaches the set time T. At this time, it is preferable that αA≈α2> α1≈αB.

[Second mode (second step)]
In the second mode (second step), the first fan 31 is stopped and the second fan 32 is rotated. Due to the rotation of the second fan 32, the outside air passes through the second opening 92, and further passes through the gap 22 between the absorbing / releasing members 21, 21 of the second absorbing / releasing means 20 and the outside of the absorbing / releasing members 21 at both ends. It is sent into the house 90. The inflow gas from the second opening 92 contacts the intake / discharge member 21.

At this time, in the second suction / release member 21, the KHCO ₃ existence rate α2 is sufficiently larger than the equilibrium value α0 in the outside air (α2> α0), and therefore the direction in which KHCO ₃ is converted to K ₂ CO ₃ (leftward direction of Equation 1) ) Moves the equilibrium. By this equilibrium reaction, CO ₂ is released from the absorption / release member 21. This CO ₂ is mixed with the incoming gas. This increases the CO ₂ partial pressure of the incoming gas. As described in the first mode, at this time, the H ₂ O partial pressure of the feed gas is almost unchanged. The KHCO ₃ abundance ratio α2 of the suction / release member 21 is larger than the equilibrium value αB when the H ₂ O partial pressure is equal to the outside air and the CO ₂ partial pressure is equal to the set partial pressure in the house 90 (α2> αB). The suction / release member 21 can release CO ₂ until the CO ₂ concentration of the feed gas becomes equal to or higher than the set concentration. Therefore, a feed gas having a CO ₂ concentration equal to or higher than the set concentration can be supplied into the house 90. The KHCO ₃ existence ratio α2 of the absorption / release member 21 decreases with the release of CO ₂ .

  Furthermore, the atmospheric gas in the greenhouse 90 is pushed by the flow of the outside air, and passes through the gap 12 between the absorption / release members 11 of the first absorption / release means 10 and the outside of the absorption / release members 11 at both ends. Then, it is sent to the outside through the first opening 91. This delivery gas comes into contact with the first suction / release member 11.

In the first suction / release member 11, since the KHCO ₃ abundance ratio α1 is smaller than the in-house equilibrium value α90 (α1 <α90), the equilibrium is maintained in the direction in which K ₂ CO ₃ is converted to KHCO ₃ (rightward in Expression 1). Moving. By this equilibrium reaction, the absorption / release member 11 absorbs CO ₂ in the delivery gas. This reduces the CO ₂ partial pressure of the delivery gas. As described in the first mode, the H ₂ O partial pressure of the delivery gas is almost unchanged at this time. The KHCO ₃ abundance ratio α1 of the intake / release member 11 is smaller than the equilibrium value αA when the H ₂ O partial pressure is equal to that in the house 90 and the CO ₂ partial pressure is equal to that in the outside air (α1 <αA). Until the CO ₂ concentration becomes lower, the absorption / release member 11 can absorb CO ₂ from the delivery gas. The delivery gas is discharged outdoors with a lower CO ₂ concentration than the outside air. The KHCO ₃ existence ratio α1 of the absorption / release member 11 increases with the absorption of CO ₂ . By continuing the second mode, eventually α1> α2. Furthermore, αA≈α1> α2≈αB is approached.

  The switching means 3 determines the mode switching timing, and switches the second mode to the first mode when the switching timing is reached. For example, the switching unit 3 counts the duration of the second mode and determines whether or not the duration has reached the set time T. That is, it is determined whether or not the integrated air flow rate Q × T in the second mode is substantially the same as the internal volume V of the greenhouse 90 (Formula 4). The switching means 3 switches from the second mode to the first mode when the duration time of the second mode reaches the set time T. At this time, it is preferable that αA≈α1> α2≈αB.

In this manner, according to the carbon dioxide supply device 1, CO ₂ is stored in the greenhouse 90 for a long time by repeatedly executing the first mode (first step) and the second mode (second step). Can be supplied over time or semi-permanently. As a result, the CO ₂ concentration in the greenhouse 90 can be maintained at the set concentration. Thereby, the growth of the crop S can be promoted. Moreover, the carbon dioxide supply device 1 can absorb and release CO ₂ while ventilating the inside of the greenhouse 90. Therefore, it is suitable for summer driving. Therefore, in summer, the growth of the crop S can be sufficiently promoted in combination with the intensity of sunlight.

By using a substance (KHCO ₃ or the like) that causes an absorption / release reaction (formula 1) involving CO ₂ and H ₂ O as the absorption / release agent 2, if the humidity in the greenhouse 90 is made higher than the humidity of the outside air, the greenhouse it is possible to maintain the CO ₂ concentration in 90 automatically higher than the CO ₂ concentration in the outside air.

Absorption and release means 10 and 20 absorbs CO ₂ from the air, since it is intended to release the CO _2, it can be said that CO ₂ in the air is as it were CO ₂ feed. Therefore, it is not necessary to periodically replenish special CO ₂ raw materials such as carbon dioxide cylinders, dry ice, fossil fuels, and carbon electrodes. Therefore, maintenance and management are easy, and running costs can be suppressed. Since the gas delivered from the house 90 has a lower CO ₂ concentration than the outside air, CO ₂ loss can be suppressed.

By increasing the length along the gas flow direction of the intake / discharge members 11 and 12 (for example, about 1 m), the in-and-out gas and the intake / release members 11 and 12 can sufficiently come into contact with each other. Thereby, the absorption reaction and the release reaction of CO ₂ can be surely caused.

The KHCO ₃ abundance ratios α1 and α2 of the suction / release members 11 and 21 are repeatedly increased and decreased within the selected range (αA to αB) as the carbon dioxide supply device 1 is continuously operated. The fluctuation range of the KHCO ₃ existence ratios α1 and α2 can be adjusted by the amount of the absorption / release members 11, 21 and the duration of each mode. When the amount of the absorbent / release agent 2 is increased or the duration time of each mode is shortened, the fluctuation range of the KHCO ₃ existence ratios α1 and α2 can be made substantially zero. It is preferable to increase the amount of the absorbing / releasing members 11 and 21 as the inner volume of the house 90 is larger or the photosynthesis of the crop S is more active.

In the above description, the KHCO ₃ molar abundance α1, α2 is made uniform throughout the absorption-release members 11, 21, but the actual KHCO ₃ molar abundance α1, α2 depends on the location of the absorption-release members 11, 21. A difference may be made and a distribution may be formed along the blowing path. The abundance ratios α1 and α2 of the absorption-release members 11 and 21 on the outdoor side tend to be relatively low, and the portion of the house 90 closer to the room tends to have a relatively high abundance ratio α1 and α2. For this reason, when CO _{2 is} released by the outside air inflow, the outdoor side portion having a low abundance ratio α is first brought into contact with the inflowing gas, so that the CO ₂ concentration of the inflowing gas is increased halfway. Thereafter, the inward portion of the high abundance ratio α comes into contact with the incoming gas, and the CO ₂ concentration of the incoming gas further increases. At the time of absorbing CO ₂ by sending atmospheric gas in the house 90, the sending gas comes into contact with a portion near the room having a high abundance ratio α, thereby lowering the CO ₂ concentration of the sending gas halfway. Thereafter, the outdoor portion having a low abundance ratio α contacts the delivery gas, and the CO ₂ concentration of the delivery gas further decreases. Therefore, the fluctuation range of α1 and α2 in the outdoor portion of the absorption / release members 11 and 21 is shifted to a side lower than the selection range αA to αB. The variation range of α1 and α2 in the interior portion of the absorption / release members 11 and 21 is shifted to a higher side than the selection ranges αA to αB. Therefore, the fluctuation range of α1 and α2 as the whole of the absorption / release members 11 and 21 can be widened to the low rate side and the high rate side than the selection ranges αA to αB. Thus, feeding can be reliably increased CO ₂ concentration of the inlet gas, and can be reliably lowered CO ₂ concentration of the delivery gas.

The carbon dioxide supply device 1 is particularly suitable for use in a dry zone. This will be described with a specific example based on FIG. The relative humidity of the outside air is 10% (temperature 30 ° C.), and the CO ₂ partial pressure is 38 Pa. It is assumed that the relative humidity of the atmospheric gas in the house 90 is 80% (temperature 30 ° C.), and the CO ₂ partial pressure is 100 Pa, which is the set partial pressure. As shown in FIG. 2, at this time, the upper limit value αA of the selection range (KHCO ₃ molar abundance in an equilibrium state when the H ₂ O partial pressure is equal to the inside of the house 90 and the CO ₂ partial pressure is equal to the outside air) is , ΑA = 0.991. Further, the lower limit value αB of the selection range (KHCO ₃ abundance in an equilibrium state when the H ₂ O partial pressure is equal to that in the outside air and the CO ₂ partial pressure is equal to the set partial pressure in the house 90) is αB = 0. 976. For simplicity, KHCO ₃ prevalence α1 in the absorption and emission members 11 and 21, the distribution of [alpha] 2 is that there is no, KHCO ₃ prevalence α1 of absorbing and releasing members 11 and 21, [alpha] 2 is within the selected range αA~αB It shall be adjusted with. Therefore, 0.976 ≦ α1 ≦ 0.991 and 0.976 ≦ α2 ≦ 0.991.

At the start of the first mode, the KHCO ₃ molar abundance α1 of the first absorption / release member 11 is α1 = 0.990 (≈αA), and the KHCO ₃ molar abundance α2 of the second absorption / release member 21 is , Α2 = 0.777 (≈αB). because it is [alpha] 1> alpha B, as shown in broken lines in FIG. 2, until the CO ₂ partial pressure of 10% humidity infeed gas becomes equal to or higher than 100 Pa, sufficiently releasing CO ₂ from the first storage and release member 11. Further, since α2 <αA, as shown by the solid line in FIG. 2, the second absorbing / releasing member is used until the CO ₂ partial pressure of the delivery gas having a humidity of 80% becomes equal to or lower than the CO ₂ partial pressure (38 Pa) in the atmosphere. 21 can sufficiently absorb CO ₂ from the delivery gas.

If the operation in the first mode is continued, the KHCO ₃ molar abundance ratio α1 of the first absorption / release member 11 will eventually be reduced to α1 = 0.777 (≈αB), and the KHCO ₃ molar abundance ratio α2 of the second absorption / release member 21 will eventually be reduced. Increases to α2 = 0.990 (≈αB). Even at this time, since α1> α0, the first absorbing / releasing member 11 still has the CO ₂ releasing ability. In addition, since α2 <α90, the second absorption / release member 21 retains the CO ₂ absorption capability. At this point, the mode is switched to the second mode.

In the second mode, since it is [alpha] 2> alpha B, as apparent from the dashed line in FIG. 2, until the CO ₂ partial pressure of 10% humidity infeed gas becomes equal to or higher than 100 Pa, the CO ₂ from the second absorption and release member 21 It can be released sufficiently. Further, since α1 <αA, as is apparent from the solid line in FIG. 2, the first absorption / desorption member is used until the CO ₂ partial pressure of the delivery gas having a humidity of 80% becomes equal to or lower than the CO ₂ partial pressure (38 Pa) in the atmosphere. 11 can sufficiently absorb CO ₂ from the delivery gas.

If the operation in the second mode is continued, the KHCO ₃ molar abundance ratio α1 of the first absorption / release member 11 will eventually rise to α1 = 0.990 (≈αB), and the KHCO ₃ molar abundance ratio α2 of the second absorption / release member 21 will eventually increase. Decreases to α2 = 0.777 (≈αB). At this time, the mode is switched to the first mode.

In this way, in a dry environment where the relative humidity of the outside air is about 10%, by repeating the first and second modes, an inflow gas having a CO ₂ partial pressure of 100 Pa (≈CO ₂ concentration 1000 ppm) or more can be obtained. The house 90 can be continuously supplied, and the house 90 can be maintained in a high CO ₂ concentration environment with a CO ₂ partial pressure of about 100 Pa. If the amount of the first and second absorbing / releasing members 11 and 21 is increased, the CO ₂ concentration in the house 90 is maintained while maintaining the KHCO ₃ existence ratio α1 and α2 at a substantially constant value of, for example, α1, α2 = 0.98. It can be maintained at about 1000 ppm (CO ₂ partial pressure is 100 Pa).

Next, the outside air is assumed to have a temperature of 30 ° C., a relative humidity of 50%, and a CO ₂ partial pressure of 38 Pa. In this case, as shown by the one-dot chain line in FIG. 2, when the CO ₂ set partial pressure in the house 90 (relative humidity 80%) is 52 Pa, αA = αB = 0.991. Therefore, the CO ₂ concentration of the house 90 can be increased to 520 ppm. In this case, the KHCO ₃ abundance ratios α1, α2 of the suction / release members 11, 21 are absorbed so that they are maintained at a substantially constant value (α1 = α2 = 0.991) during the continuous operation of the first and second modes. The amount of discharge members 11 and 21 and the mode switching timing are adjusted. When the CO ₂ set partial pressure in the house 90 is larger than 52 Pa, αB becomes larger than αA (= 0.991). Therefore, the upper limit of the CO ₂ concentration that can be set is 520 ppm.
As described above, the carbon dioxide supply device 1 can increase the CO ₂ set concentration in the house 90 as the humidity of the outside air is lower.
The numerical values such as α1, α2, αA, αB and the like are merely examples, and the present invention is not limited to these exemplified values.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those already described, and the description thereof is omitted.
[Second Embodiment]
FIG. 3 shows a second embodiment of the present invention. The carbon dioxide supply device 1 of the second embodiment further includes carbon dioxide supplementing means 40. The carbon dioxide replenishing means 40 includes an absorption / release agent container 41, an air supply pump 42 (air supply means), and a suction pump 43. These elements 41, 42, and 43 are disposed outside the greenhouse 90, but may be accommodated inside the greenhouse 90.

The container 41 has pressure resistance against an internal pressure that is, for example, about one-tenth of the atmospheric pressure, and more preferably has pressure resistance against an internal pressure that is higher than atmospheric pressure. The second absorption / release agent 2A is accommodated in the container 41 in a powder state. The point that the second absorption / release agent 2A is composed of an equilibrium coexisting material of KHCO ₃ and K ₂ CO ₃ is the same as the first absorption / release agent 2 of the first and second absorption / release members 11 and 21. The 2nd absorption / release agent 2A is not restricted to powder form, and may be plate shape or lump shape.

  An air supply pump 42 is connected to one end of the container 41. An opening / closing valve 48 is provided on a pipe line connecting the air supply pump 42 and the container 41. An open path 44 is provided at the other end of the container 41. An opening degree adjusting valve 45 is provided in the open path 44. A suction pump 43 is connected to one end of the container 41. The suction pump 43 is constituted by a vacuum pump. The suction pump 43 may be a scroll-type vacuum pump, a reciprocating-type vacuum pump, or a diaphragm-type vacuum pump.

  It is preferable to use a solar battery as a power source such as the pumps 42 and 43 of the carbon dioxide supplementing means 40. As a result, it is possible to operate even in a place where commercial power cannot be supplied. A diesel generator, a commercial power source, or the like may be used as a power source for the pumps 42 and 43 and the like.

  A replenishment path 46 is connected to the exhaust port 43 b of the suction pump 43. The replenishment path 46 extends to the greenhouse 90. The replenishment path 46 is bifurcated via a three-way valve 47. Replenishment nozzles 46 a and 46 b are provided at the tips of the branch paths of the replenishment path 46. The tips of the replenishing nozzles 46a and 46b are inserted into the inside of the greenhouse 90 and opened. A replenishment path 46 communicates the exhaust port 43 b of the suction pump 43 and the inside of the greenhouse 90.

  The tip of the first replenishing nozzle 46 a is disposed in the vicinity of the first suction / discharge unit 10 and closer to the center of the greenhouse 90 than the first suction / release unit 10. The tip of the second replenishing nozzle 46 b is disposed in the vicinity of the second suction / release means 20 and closer to the center of the greenhouse 90 than the second suction / release means 20.

  A carbon dioxide concentration sensor 4 is provided in the greenhouse 90. Although not shown, the detection signal line of the carbon dioxide concentration sensor 4 is connected to the controller 3.

  The controller 3 also has a function as a control unit for the carbon dioxide supplementing unit 40 in addition to a function as a switching unit for the first and second modes. The controller 3 is added with a control program for the pumps 42 and 43 and valves 45, 47 and 48, a drive circuit for these elements 42, 43, 45, 47 and 48, and the like. A control signal line (not shown) of the controller 3 is connected to the pumps 42 and 43 and the valves 45, 47 and 48.

In the second embodiment, the replenishment preparation step and the replenishment step are performed by the carbon dioxide replenishment means 40 separately from the first step (first mode) and the second step (second mode).
[Replenishment preparation process]
In the replenishment preparation step, the on-off valve 48 is opened. Then, the air supply pump 42 sends air into the absorbent / release agent container 41 in accordance with a command from the controller 3. Thereby, CO ₂ in the air can be adsorbed by the second absorption / release agent 2A. At this time, the suction pump 43 is stopped. The opening degree adjusting valve 45 is fully opened so that air is exhausted from the open path 44. As a result, the interior of the absorbent / release agent container 41 can be maintained at substantially atmospheric pressure. You may close the opening degree adjustment valve 45, and make the inside of the adsorption / release agent container 41 into a pressure higher than atmospheric pressure.

Further, the carbon dioxide concentration sensor 4 detects the CO ₂ concentration of the atmospheric gas in the greenhouse 90. The detection result is input to the controller 3. The controller 3 determines whether or not to execute the replenishment step based on the detected concentration of CO ₂ . For example, when the CO ₂ detection concentration falls below a certain threshold value, the replenishment step is executed. Whether or not a replenishment process is necessary may be determined based on the decreasing gradient of the detected CO ₂ concentration.

[Replenishment process]
The operation of the replenishment process differs depending on whether the mode being executed is the first mode or the second mode. Specifically, when the CO ₂ concentration in the greenhouse 90 is lower than the threshold value in the first mode, the suction pump 43 and the first replenishing nozzle 46a are communicated by the three-way valve 47, and the suction pump 43 and the second replenishing nozzle are connected. Block 46b. The on-off valve 48 is closed and the air supply pump 42 is stopped. The opening control valve 45 is fully closed or half open. In particular, when the suction pump 43 is a vacuum pump having a low ultimate vacuum such as a diaphragm vacuum pump, it is preferable to open the opening degree adjustment valve 45 halfway. Then, the suction pump 43 is driven. Thereby, the pressure in the container 41 decreases. Therefore, in the second absorbing / releasing agent 2A, the equilibrium moves in the direction in which KHCO ₃ is converted to K ₂ CO ₃ (the left direction in Equation 1), and CO ₂ is released from the second absorbing / releasing agent 2A. The CO ₂ -containing gas in the container 41 is sucked by the suction pump 43. Even if the ultimate vacuum degree of the suction pump 43 is small, the CO ₂ -containing gas in the container 41 can be reliably sucked by opening the opening degree adjustment valve 45 halfway. The suction pump 43 discharges the sucked CO ₂ -containing gas from the exhaust port 43b. This CO ₂ -containing gas is introduced into the first replenishing nozzle 46a through the three-way valve 47, and blown out from the first replenishing nozzle 46a to the vicinity of the first suction / release means 10 in the greenhouse 90. Thereby, CO ₂ can be replenished into the greenhouse 90 separately from the first suction / release means 10. Therefore, the CO ₂ concentration in the greenhouse 90 can be maintained at a high concentration equal to or higher than the threshold value. As a result, the growth of the crop S can be surely promoted.

In the greenhouse 90 in the first mode, an atmospheric gas flow is formed by the first fan 31 from the first suction / release means 10 side toward the second suction / release means 20 side. The CO ₂ -containing gas from the first replenishing nozzle 46a joins relatively upstream of this flow. Thereby, CO ₂ from the absorbent / release agent container 41 can be spread over a wide range in the greenhouse 90.

When the CO ₂ concentration in the greenhouse 90 is below the threshold in the second mode, the suction pump 43 and the second refill nozzle 46b are communicated by the three-way valve 47, and the suction pump 43 and the first refill nozzle 46a are shut off. The point that the on-off valve 48 is closed, the air supply pump 42 is stopped, the opening degree adjustment valve 45 is fully closed or half-opened, and then the suction pump 43 is driven is the same as in the first mode. As a result, as in the first mode, the pressure in the absorbent / release agent container 41 decreases, and CO ₂ is released from the second absorbent / release agent 2A. The gas in the absorbent / release agent container 41 containing CO ₂ is sucked by the suction pump 43 and blown out from the second replenishing nozzle 46 b to the vicinity of the second suction / release means 20 in the greenhouse 90. As a result, CO ₂ can be replenished into the greenhouse 90 separately from the second suction / release means 20. Therefore, the CO ₂ concentration in the greenhouse 90 can be maintained at a high concentration equal to or higher than the threshold value, and the growth of the crop S can be surely promoted.

In the greenhouse 90 in the second mode, an atmospheric gas flow is formed by the second fan 32 from the second suction / release means 20 side toward the first suction / release means 10 side. The CO ₂ -containing gas from the second replenishing nozzle 46b joins relatively upstream of this flow. Thereby, CO ₂ from the absorbent / release agent container 41 can be spread over a wide range in the greenhouse 90.

[Third Embodiment]
FIG. 4 shows a third embodiment of the present invention. The carbon dioxide supply device 1 according to the third embodiment further includes first and second spray nozzles 51 and 52. The first spray nozzle 51 is disposed in the vicinity of the first suction / release means 10 inside the greenhouse 90. The second spray nozzle 52 is disposed in the vicinity of the second suction / release means 20 inside the greenhouse 90. These spray nozzles 51 and 52 can rotate 180 degrees in the horizontal direction between the direction facing the suction / release means 10 and 20 and the direction facing the side opposite to the suction / release means 10 and 20. A water supply source (not shown) is connected to the base end portions of the spray nozzles 51 and 52. Water from a water supply source is supplied to the spray nozzles 51 and 52. The spray nozzles 51 and 52 atomize water and spray it from the spray ports 51a and 52a.
The direction of the spray nozzle 51 may be fixed toward the first suction / release unit 10. The direction of the spray nozzle 52 may be fixed toward the second suction / release unit 20.

  A control program and a drive circuit for the spray nozzles 51 and 52 are added to the controller 3. The controller 3 controls the direction of the spray nozzles 51 and 52 and the spray. The controller 3 has a function as a control means for the spray nozzles 51 and 52 in addition to a function as a switching means.

As shown by a solid line in FIG. 4, in the first mode, the spray nozzle 51 is directed to the side opposite to the first suction / release means 10. In addition, the spray nozzle 52 is directed to the second suction / release means 20. Water is sprayed into the greenhouse 90 from the spray nozzle 51. When this fog evaporates, it takes away the heat of vaporization. Therefore, the inside of the greenhouse 90 can be cooled. At the same time, water is sprayed from the spray nozzle 52 toward the second suction / release means 20. Thereby, the water vapor partial pressure around the second suction / release means 20 is increased. Therefore, in the absorption / release member 21, the equilibrium can surely move in the direction in which K ₂ CO ₃ is converted to KHCO ₃ , and CO ₂ absorption by the absorption / release member 21 can be promoted. In the first mode, spraying from the spray nozzle 51 may be stopped.

As shown by a two-dot chain line in FIG. 4, in the second mode, the spray nozzle 51 is directed toward the first suction / release means 10. Further, the spray nozzle 52 is directed to the side opposite to the second suction / release means 20. Water is sprayed from the spray nozzle 51 toward the first suction / release means 10. Thereby, the water vapor partial pressure around the first suction / release unit 10 is increased. Therefore, in the absorption / release member 11, the equilibrium can be reliably moved in the direction in which K ₂ CO ₃ is converted to KHCO ₃ , and CO ₂ absorption by the absorption / release member 11 can be promoted. In addition, water is sprayed into the greenhouse 90 from the spray nozzle 52. When this fog evaporates, it takes away the heat of vaporization. Therefore, the inside of the greenhouse 90 can be cooled. In the second mode, spraying from the spray nozzle 52 may be stopped.

[Fourth Embodiment]
FIG. 5 shows a fourth embodiment of the present invention. The carbon dioxide supply device 1 according to the fourth embodiment further includes first and second heating means 61 and 62 and first and second cooling means 63 and 64.

  The first heating means 61 is disposed in the vicinity of the first suction / release means 10 inside the greenhouse 90. The second heating means 62 is disposed in the vicinity of the second suction / release means 20 inside the greenhouse 90. The heating means 61 and 62 may be electric heaters, heat exchangers, or heat pumps.

  The first cooling means 63 is disposed near the first suction / release means 10 inside the greenhouse 90. The second cooling means 64 is disposed in the vicinity of the second suction / release means 20 inside the greenhouse 90. The cooling means 63 and 64 may be a spray type cooler, a heat exchanger, or a heat pump.

  The first heating / cooling means 61 and 63 are not limited to the illustrated positions as long as the first heating / cooling means 61 and 63 are arranged in the vicinity of the first suction / release means 10. The second heating / cooling means 62 and 64 are not limited to the illustrated positions as long as the second heating / cooling means 62 and 64 are arranged near the second suction / release means 20.

  The controller 3 is added with control programs and drive circuits for the heating / cooling means 61 to 64. The controller 3 also has a function as a control unit for the heating / cooling units 61 to 64 in addition to a function as a switching unit.

In the first mode, the first heating means 61 is operated and the second heating means 62 is stopped. And the 1st cooling means 63 is stopped and the 2nd cooling means 64 is operated. The first sucking / releasing means 10 can be heated by the operation of the first heating means 61. Thereby, in the absorption / release agent 2 in the first absorption / release unit 10, the equilibrium moves in the direction in which KHCO ₃ is converted to K ₂ CO ₃ , and the release of CO ₂ from the first absorption / release unit 10 can be promoted. . Further, the second suction / release means 20 can be cooled by the operation of the second cooling means 64. Thereby, in the absorbing / releasing agent 2 in the second absorbing / releasing means 20, the equilibrium moves in the direction in which K ₂ CO ₃ is converted to KHCO _3, and the CO ₂ absorption of the second absorbing / releasing means 20 can be promoted.

In the second mode, the first heating means 61 is stopped and the second heating means 62 is operated. And the 1st cooling means 63 is operated and the 2nd cooling means 64 is stopped. The second suction / release means 20 can be heated by the operation of the second heating means 62. Thereby, in the absorption / release agent 2 in the second absorption / release means 20, the equilibrium moves in the direction in which KHCO ₃ is converted to K ₂ CO ₃ , and the release of CO ₂ from the second absorption / release means 20 can be promoted. . Further, the first sucking / releasing means 10 can be cooled by the operation of the first cooling means 63. Thereby, in the absorbing / releasing agent 2 in the first absorbing / releasing means 10, the equilibrium moves in the direction in which K ₂ CO ₃ is converted to KHCO _3, and the CO ₂ absorption of the first absorbing / releasing means 10 can be promoted.

[Fifth Embodiment]
FIG. 6 shows a fifth embodiment of the present invention. In the fifth embodiment, the first suction / release means 10 further includes a pair of upper and lower cover members 15 and 16. These covering members 15 and 16 are plate-shaped. A covering member 15 is placed over the absorbing member 11. The covering member 15 straddles between the plurality of absorbing members 11 and closes the opening at the upper end of the gap 12 between the adjacent absorbing members 11 and 11. A covering member 16 is provided below the absorbing member 11. The covering member 16 straddles between the plurality of absorbing members 11 and closes the opening at the lower end of the gap 12 between the adjacent absorbing members 11 and 11. Thereby, when the in / out gas passes through the inside of the gap 12, it can be prevented from leaking from the upper end portion or the lower end portion of the gap 12. Therefore, the in-and-out gas can be brought into contact with substantially the entire surface of the absorbing member 11, and the CO ₂ absorption / release reaction of the absorbing member 11 can be caused reliably.

Similarly, a pair of upper and lower cover members 25 and 26 are also provided in the second suction / release unit 20. These covering members 25 and 26 are plate-shaped. A covering member 25 is placed over the absorbing member 21. The covering member 25 straddles between the plurality of absorbing members 21 and closes the opening at the upper end of the gap 22 between the adjacent absorbing members 21 and 21. A covering member 26 is provided below the absorbing member 21. The covering member 26 straddles between the plurality of absorbing members 21 and closes the opening at the lower end of the gap 22 between the adjacent absorbing members 21 and 21. Thereby, when the in-and-out gas passes through the gap 22, it can be prevented from leaking from the upper end or the lower end of the gap 22. Therefore, the in-and-out gas can be brought into contact with substantially the entire surface of the absorbing member 21, and the CO ₂ absorption / release reaction of the absorbing member 21 can surely occur.

[Sixth Embodiment]
The positional relationship among the openings 91, 92, the suction / release means 10, 20, and the fans 31, 32 is not limited to that of the above-described embodiment, and can be modified as appropriate. FIG. 7 shows a sixth embodiment of the present invention. In the sixth embodiment, the suction / release means 10 is arranged outside the opening 91 and thus outside the greenhouse 90. The fan 31 is provided inside the opening 91, and as a result, is arranged inside the greenhouse 90 from the suction / release means 10.

  Similarly, the suction / release means 20 is disposed outside the opening 92 and thus outside the greenhouse 90. The fan 32 is provided inside the opening 92, and thus is disposed inside the greenhouse 90 from the suction / release means 20.

In 6th Embodiment, it can avoid that the absorption-and-release members 11 and 21 become high temperature with the heat | fever in the greenhouse 90. FIG. Thereby, the absorption characteristics of the absorption / release members 11 and 21 can be improved.
In addition, since the suction / discharge members 11 and 21 are positioned upstream of the fans 31 and 32 along the transfer direction on the outside air inlet side, the pressure of the outside air in contact with the inlet / outlet members 11 and 21 is reduced. Can do. Thus, it is possible to promote the CO ₂ release from storage and release members 11, 21. On the gas delivery side, the absorption / release members 21 and 11 are positioned downstream of the fans 32 and 31 along the delivery direction, so that the pressure of the atmospheric gas can be increased and brought into contact with the absorption / release members 21 and 11. Thus, it is possible to promote CO ₂ absorption of absorption and release members 21, 11.

[Seventh Embodiment]
The absorption / release means is not limited to being provided in both the first opening 91 and the second opening 92, and may be provided only in one of the openings 91 and 92. FIG. 8 shows a seventh embodiment of the present invention. The carbon dioxide supply device 1 of the seventh embodiment includes only the absorption / release means 10 on the first opening 91 side as the absorption / release means, and the second absorption / release means 20 on the second opening 92 side is omitted. .

  In the seventh embodiment, the air blowing means is composed of a single forward / reverse fan 33. The forward / reverse fan 33 is disposed in the first opening 91, faces the end face of each of the absorption / release members 11, and faces the gap 12 between the absorption / release members 11. The forward rotation direction of the forward / reverse fan 33 is a direction in which outside air is blown into the greenhouse 90. The second opening 92 is not provided with a fan.

  A temperature sensor 5 is provided in the greenhouse 90. A detection signal line of the temperature sensor 5 is connected to the controller 3.

  Furthermore, the carbon dioxide supply device 1 of the seventh embodiment is provided with carbon dioxide supplementing means 40. In the carbon dioxide replenishing means 40 of the seventh embodiment, the replenishment path 46 is not branched. One refill nozzle 46 c is provided at the tip of the refill path 46. The tip of the refill nozzle 46c faces the inside of the greenhouse 90.

Also in the seventh embodiment, the first mode and the second mode are executed alternately. The first mode is executed when the KHCO ₃ existence ratio in the suction / release member 11 is relatively large. In the first mode, the forward / reverse fan 33 is rotated in the forward direction. As a result, outside air passes through the first opening 91 and further passes through the gaps 12 between the suction / release members 11 and the outside of the suction / release members 11 at both ends while contacting the respective suction / release members 11 of the suction / release means 10. 90 is sent into the interior. At this time, CO ₂ is released from the absorption / release member 11 by the contact between the outside air and the absorption / release member 11, and this CO ₂ is supplied into the greenhouse 90 together with the outside air. As a result, the CO ₂ concentration in the greenhouse 90 can be increased. The KHCO ₃ existence ratio of the absorption / release member 11 is lowered by the conversion of KHCO ₃ to K ₂ CO ₃ .

  The gas in the greenhouse 90 is exhausted from the second opening 92 by being pushed by the outside air from the first opening 91. For example, when the integrated air flow rate Q × T in the first mode becomes substantially the same as the internal volume V of the greenhouse 90, the fan 33 is stopped and the first mode is ended.

In the seventh embodiment, after the end of the first mode, the pause mode is interposed during the transition to the second mode, and the transition to the second mode is not immediately performed. In the sleep mode, the fan 33 is stopped. When the CO ₂ concentration in the greenhouse 90 is lowered due to the carbon assimilation of the crop S or the diffusion of air through the openings 91 and 92 during the pause mode, the carbon dioxide concentration sensor 4 detects this. The controller 3 operates the suction pump 43 of the carbon dioxide supplementing means 40 in accordance with the detection signal from the carbon dioxide concentration sensor 4. Thus, the suction pump 43 sucks the CO ₂ -containing gas from the inside of the absorption / release agent container 41. And supplies the CO ₂ containing gas from the refill nozzle 46c in a plastic greenhouse in 90. As a result, the CO ₂ concentration in the greenhouse 90 can be maintained high. In the sleep mode, the first and second openings 91 and 92 may be closed.

In the rest mode, the temperature in the greenhouse 90 is further detected by the temperature sensor 5. The detection result is input to the controller 3. The controller 3 switches from the sleep mode to the second mode when the degree of increase in the detected temperature exceeds a predetermined value (for example, 1 to 3 ° C.). The timing of switching from the pause mode to the second mode is not limited to being determined based on the temperature change in the greenhouse 90, but may be determined based on the change in the CO ₂ concentration in the greenhouse 90. You may decide based on time.

In the second mode, the forward / reverse fan 33 is rotated in the reverse direction. As a result, the atmospheric gas having a high CO ₂ concentration in the greenhouse 90 passes through the gap 12 between the absorption / release members 11 and the outside of the absorption / release members 11 at both ends while contacting the respective absorption / release members 11 of the absorption / release means 10. Then, it is discharged through the first opening 91. At this time, by contact with a high CO ₂ concentration in the atmosphere gas and the absorbing and releasing member 11, CO ₂ in the atmospheric gas is absorbed by the member 11 out absorbing. Thereby, the KHCO ₃ presence rate in the absorption / release member 11 increases.

  As the atmospheric gas in the greenhouse 90 is exhausted from the first opening 91, outside air enters the greenhouse 90 from the second opening 92. For example, when the integrated air flow rate Q × T in the second mode becomes substantially the same as the internal volume V of the greenhouse 90, the fan 33 is stopped and the second mode is ended.

Immediately after the end of the second mode, the fan 33 is rotated in the forward direction with little or no interval to switch to the first mode. Thereby, it is possible to shorten the period during which the CO ₂ concentration in the vinyl house 90 is low. During the transition from the second mode to the second mode, the pause mode may be interposed.

[Eighth Embodiment]
The absorption / release members 11 and 21 are not limited to a flat plate shape. For example, as shown in FIG. 9A, the absorption / release member may be composed of a honeycomb lattice structure 81. As illustrated in FIG. 9B, the absorption / release member may be configured by a square lattice structure 82. Although illustration is omitted, the absorbing / releasing member may be composed of another lattice structure such as a triangular lattice. Then, it can increase the contact area between the input and the gas feed and absorbing and releasing member can occur reliably absorbing and releasing CO _2. The absorption / release members 81 and 82 having a lattice structure such as a honeycomb or a square lattice are not limited to being arranged in parallel to the blowing direction of the blower fans 31 and 32, and are arranged so as to intersect or be orthogonal to the blowing direction. May be.

[Ninth Embodiment]
The absorption / release members 11 and 21 are not limited to those obtained by binding the powder of the absorption / release agent 2 with a binder. FIG. 10A and FIG. 10B show a ninth embodiment of the present invention. The ninth embodiment relates to a modified example of the absorption / release members 11 and 21. In this embodiment, the suction / release members 11 and 21 are configured by a powder container 70. The powder container 70 includes a frame 71 and a pair of covers 72. The frame 71 is made of resin, for example, but may be made of metal or other material. The frame 71 is a square having a side length of about 1 m. However, the frame 71 is not limited to this and may be, for example, a vertically long or horizontally long rectangle. The thickness of the frame 71 (the vertical dimension in FIG. 10B) is, for example, about 1 mm, but is not limited thereto.

  The cover 72 is made of, for example, cloth and has air permeability. A pair of covers 72 are stretched on both sides of the frame 71 in the thickness direction. Each cover 72 covers the space inside the frame 71. The peripheral edge of the cover 72 is fixed to the frame 71.

The powdered absorption / release agent 2 </ b> B is accommodated in the space inside the frame 71. The absorbing / releasing agent powder 2 </ b> B is confined in the space inside the frame 71 by the pair of covers 72. The point that the absorbent / release agent powder 2B is an equilibrium coexistent of KHCO ₃ and K ₂ CO ₃ is the same as the binder-bound / release agent 2 in the embodiment described above.

According to the ninth embodiment, the outside air or the atmospheric gas in the greenhouse 90 can enter the space in the frame 71 through the cover 72 and can sufficiently come into contact with the powdery absorption / release agent 2B. Therefore, the absorption / release reaction of CO _{2 by} the absorption / release agent 2B can surely occur. Carbon dioxide released from the absorption / release agent 2B can be supplied to the greenhouse 90 through the cover 72.

  The powder container 70 is arranged so as to be orthogonal to the surfaces of the openings 91 and 92 and along the blowing direction of the blowing means 30 as in the case of the absorption / release members 11 and 12 of the above-described embodiment (FIGS. 1 to 8). The Thereby, the pressure loss of ventilation can be suppressed small. You may arrange | position the powder container 70 so that it may cross | intersect or may be orthogonal to the ventilation direction of the ventilation means 30. FIG.

[Deformation of absorbent / release agent]
The absorption / release agent 2, 2A, 2B of the present invention is not limited to an equilibrium coexisting substance of potassium hydrogen carbonate and potassium hydrogen carbonate, but is an equilibrium coexisting substance of sodium hydrogen carbonate (NaHCO ₃ ) and sodium carbonate (Na ₂ CO ₃ ). It may be an equilibrium coexistence of lithium hydrogen carbonate (LiHCO ₃ ) and lithium carbonate (Li ₂ CO ₃ ), and may be ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) and ammonium hydrogen carbonate ((NH ₄ ). It may be an equilibrium coexisting substance with HCO ₃ ), or may be an equilibrium coexisting substance of an amine carbonate compound (amine carbonate) and a hydrogencarbonate amine compound (amine carbonate). The amine carbonate is excellent in carbon dioxide absorption. Amine is obtained by substituting hydrogen of ammonia with an alkyl group, and ammonia can be said to be a kind of amine. On the other hand, since amine is unstable, an amine carbonate group may be fixed by bonding to a carbon chain of a polymer such as polystyrene. The absorbent / release agent 2, 2A, 2B may contain sesquicarbonate (X ₂ CO ₃ .XHCO ₃ .2H ₂ O, where X = K, Na, Li, NH ₄ , or an amine compound). . The absorbing / releasing agent 2, 2A, 2B may be an equilibrium coexisting substance of sesquicarbonate and sesquibicarbonate.

The absorption / release agents 2, 2A, 2B may contain a carbonate hydrate having a structure represented by the chemical formula X ₂ CO ₃ .yH ₂ O. Here, X = K, Na, Li, NH ₄ , or an amine compound, and y is a natural number. In this case, the following equilibrium reaction occurs.
_{X 2 CO 3 · yH 2 O} + CO 2 ⇔ XHCO 3 + (y-1) H 2 O ( Equation 5)
Therefore, the carbonate hydrate coexists in equilibrium with the bicarbonate. As shown in Equation 5, in this equilibrium reaction, carbon dioxide (CO ₂ ) and water vapor (H ₂ O) are separated on both sides of the reaction equation. Therefore, this absorption / release agent releases CO _{2 when} it comes in contact with high humidity gas, and absorbs CO _{2 when} it comes in contact with low humidity gas. Therefore, this absorbent / release agent is suitable for use under conditions where the humidity in the carbon dioxide utilization room is lower than the humidity of the outside air. For example, the absorption / release agent is effective when growing a crop suitable for a dry environment in a humid area.

The absorbent / release agent 2, 2A, 2B may contain a hygroscopic substance (hygroscopic agent) such as lime or silica gel in addition to the carbonate hydrate. In general, a hygroscopic substance performs a hygroscopic release equilibrium reaction as follows.
Z + y′H ₂ O⇔Z · y′H ₂ O (Formula 6)
Here, Z is a hygroscopic substance, and y ′ is a natural number. When y = y ′ and the sum of Equation 5 and Equation 6 is taken, the following equilibrium reaction equation is obtained.
_{X 2 CO 3 · yH 2 O} + Z + CO 2 + H 2 O ⇔ XHCO 3 + Z · yH 2 O ( Formula 7)
For example, when X = Na, an equilibrium reaction as shown in the following formula occurs.
Na ₂ CO ₃ .10H ₂ O + Z + CO ₂ + H ₂ O⇔ NaHCO ₃ + Z · 10H ₂ O (Formula 8)
In Equation 8, y = 10. As shown in Equation 7 and Equation 8, in this equilibrium reaction, carbon dioxide (CO ₂ ) and water vapor (H ₂ O) appear on the same side (left side) of the reaction equation. Therefore, this absorption / release agent releases CO ₂ by contact with a low-humidity gas and absorbs CO ₂ by contact with a high-humidity gas. Therefore, the absorption / release agent is suitable for use in a general greenhouse 90 where the humidity is higher than the outside air.
The adsorbent Z is preferably silica gel.

The present invention is not limited to the above-described embodiment, and various modifications can be made without changing the gist of the invention.
The present invention is not limited to the greenhouse 90 but can be applied to various carbon dioxide utilization rooms that require a carbon dioxide environment having a higher concentration than the atmosphere. Examples of the carbon dioxide utilization room other than the greenhouse 90 include a storage room for fresh products (vegetables, meat, etc.), a fermentation room for fermentation bacteria, a brewing room, and the like.

The absorbent / release agent 2, 2A, 2B may contain an equilibrium coexisting product of two or more carbonates or hydrates thereof and bicarbonate. The absorbing / releasing agent 2, 2B of the first absorbing / releasing means 10 and the absorbing / releasing agent 2, 2B of the second absorbing / releasing means 20 contain different coexisting carbonates or their hydrates and bicarbonates. It may be. The component of the second absorption / release agent 2A of the carbon dioxide supplementing means 40 (FIGS. 3 and 8) is different from that of the first absorption / release agent 2 or 2B of the absorption / release means 10, 20 or a carbonate thereof or a hydrate thereof An equilibrium coexisting substance with a hydrogen salt may be contained.
The absorbing / releasing agent 2, 2B or the absorbing / releasing means 10, 20 only needs to be disposed on the blowing path of the blowing means. It is only necessary that the air blown by the blowing means passes through the absorption / release agents 2, 2 </ b> B or the absorption / release means 10, 20. May be provided. For example, a duct extending from the first opening or the second opening to the outside of the carbon dioxide utilization chamber 90 may be provided, and the absorbent / release agent 2, 2B or the absorption / release means 10, 20 may be provided in the duct.
In the seventh embodiment, the absorption / release means may be provided in the second opening 92 instead of the first opening 91. The absorbing / releasing agent 2, 2 </ b> B or the absorbing / releasing means 10, 20 may be provided, for example, in the central portion of the carbon dioxide utilization chamber 90.

The mode switching timing is not limited to being determined based on the mode duration (T≈Q / V) corresponding to the integrated air flow, but the integrated air flow itself is measured, and the measured value of the integrated air flow is carbon dioxide. It may be set when the internal volume V of the chamber 90 is almost reached. The mode may be switched based on the mode duration set regardless of the integrated air flow rate. Alternatively, the mode may be switched based on the CO ₂ concentration in the carbon dioxide utilization chamber 90, the temperature in the carbon dioxide utilization chamber 90, and the like.

  In the second and seventh embodiments (FIGS. 3 and 8), the carbon dioxide replenishing means 40 may be a cylinder filled with carbon dioxide or a dry ice container, and fossil fuel such as kerosene. The combustion part may be used.

  A plurality of embodiments may be combined with each other. For example, the carbon dioxide supply device 1 may include both the carbon dioxide supplementing means 40 and the spray nozzles 51 and 52. The carbon dioxide supply device 1 may include both the carbon dioxide supplementing means 40 and the heating / cooling means 61 to 64. The carbon dioxide supply device 1 may include both the spray nozzles 51 and 52 and the heating / cooling means 61 to 64. The carbon dioxide supply device 1 may include both the carbon dioxide supplementing means 40, the spray nozzles 51 and 52, and the heating / cooling means 61 to 64. Also in the second, third, fourth, and seventh embodiments (FIGS. 1, 3 to 5, and 8), the first absorbing / releasing means 10 is provided with covering members 15 and 16, and the second absorbing / releasing means 20 is provided. The covering members 25 and 26 may be provided.

  Also in the first to sixth embodiments (FIGS. 1, 3 to 7), a pause mode is interposed during the transition from the first mode to the second mode or during the transition from the second mode to the first mode. May be.

In the first to sixth embodiments (FIGS. 1 and 3 to 7), the forward rotation dedicated fans 31 and 32 may be replaced with forward and reverse fans 33, respectively. In the seventh embodiment (FIG. 8), forward and reverse fans 33 may be provided in the first and second openings 91 and 92, respectively. In this case, in the first mode, the forward / reverse fan 33 (first air blower) of the first opening 91 is rotated forward to send outside air into the carbon dioxide utilization chamber 90 from the first opening 91, and The forward / reverse fan 33 having two openings 92 is reversely rotated to forcibly exhaust the atmospheric gas in the carbon dioxide utilization chamber 90 from the second opening 92. In the second mode, the forward / reverse fan 33 (second air blowing section) of the second opening 92 is rotated forward to send outside air into the carbon dioxide utilization chamber 90 from the second opening 92 and the first opening. The forward / reverse fan 91 of 91 is reversely rotated to forcibly exhaust the atmospheric gas in the carbon dioxide utilization chamber 90 from the first opening 91.
In the seventh embodiment (FIG. 8), the forward rotation dedicated fan 31 may be provided in the first opening 91 and the forward rotation dedicated fan 32 may be provided in the second opening 92 instead of the forward / reverse fan 33. In this case, the operations of the fans 31 and 32 in the first and second modes are the same as those in the first to sixth embodiments (FIGS. 1 and 3 to 7).
The air blowing means 30 is not limited to being provided in the first opening 91 or the second opening 92, and may be disposed, for example, inside the carbon dioxide utilization chamber 90.

  The suction pump 43 of the carbon dioxide replenishing means 40 is provided in the carbon dioxide utilization chamber 90 so that the gas sucked from the absorbent / release agent container 41 is directly supplied into the carbon dioxide utilization chamber 90 from the exhaust port 43b of the suction pump 43. It may be. The exhaust port 43b of the suction pump 43 may also serve as a replenishment nozzle for the replenishment path.

  The present invention can be applied to, for example, application of carbon dioxide to a greenhouse for growing agricultural crops and horticultural crops.

S crop 1 carbon dioxide supply device 2 absorption / release agent 2A second absorption / release agent 2B powdered absorption / release agent 3 controller (switching means)
4 Carbon dioxide concentration sensor 5 Temperature sensor 10 First sucking / releasing means 11 Absorbing / releasing member 12 Clearance 20 Second sucking / releasing means 21 Absorbing / releasing member 22 Clearance 30 Air blower 31 Fan (first air blower)
32 fans (second air blower)
33 Forward / reverse fan (fan)
40 Carbon dioxide replenishment means 41 Adsorbent / release agent container 42 Air supply pump (air supply means)
43 Suction pump 43b Exhaust port 44 Opening path 45 Opening adjustment valve 46 Replenishment path 46a First replenishing nozzle 46b Second replenishing nozzle 46c Replenishing nozzle 47 Three-way valve 48 Opening and closing valve 51 Spray nozzle 52 Spray nozzle 61 First heating means 62 Second Heating means 63 First cooling means 64 Second cooling means 70 Powder container (absorption / release member)
71 Frame 72 Cover 81 Honeycomb structure absorption / release member 82 Square lattice structure absorption / release member 90 Plastic house (carbon dioxide utilization chamber)
91 1st opening 92 2nd opening

Claims (19)

An apparatus for supplying carbon dioxide to a carbon dioxide utilization chamber having a first opening and a second opening,
An adsorbent / release agent that causes an equilibrium reaction with absorption / release of carbon dioxide, an air blowing means that forms an air flow path through the first opening, the inside of the carbon oxide utilization chamber, and the second opening; Switching means for alternately switching between the first mode and the second mode between the sucking and releasing and the blowing mode of the blowing means, and the absorbing and releasing agent is disposed on the blowing path of the blowing means, In the first mode, the air blowing means sends outside air into the carbon dioxide using chamber from the first opening, and sends atmospheric gas in the carbon dioxide using chamber from the second opening. In the second mode, the air blowing means feeds outside air into the carbon dioxide utilization chamber from the second opening, and sends out the atmospheric gas from the first opening.   The carbon dioxide supply apparatus according to claim 1, wherein the absorption / release agent contains a component that causes an equilibrium reaction involving absorption / release of carbon dioxide and water vapor.   The carbon dioxide supply device according to claim 2, wherein the absorption / release agent also releases water vapor when releasing carbon dioxide, and also absorbs water vapor when absorbing carbon dioxide.   The absorption / release agent is potassium carbonate, sodium carbonate, lithium carbonate, sesquipotassium carbonate, sodium sesquicarbonate, lithium sesquicarbonate, ammonium carbonate, an amine carbonate compound, a polymer in which an amine carbonate group is fixed, or a hydrate thereof. It contains, The carbon dioxide supply apparatus of any one of Claims 1-3 characterized by the above-mentioned.   The carbon dioxide supply device according to claim 4, wherein the absorbent / release agent further contains a hygroscopic substance.   A first suction / release means provided in the first opening so as to allow ventilation; and a second suction / release means provided in the second opening so as to allow ventilation, wherein the first and second suction / release means are respectively provided. The carbon dioxide supply apparatus according to any one of claims 1 to 5, wherein the carbon dioxide supply apparatus includes the absorption / release agent.   The first or second absorbing / releasing means includes a plurality of absorbing / releasing members containing the absorbing / releasing agent arranged in parallel with each other, and a gap between adjacent absorbing / releasing members forms part of the air blowing path. The carbon dioxide supply device according to claim 6, wherein   The carbon dioxide supply apparatus according to claim 7, wherein the absorption / release member contains a binder that binds the absorption / release agent.   The absorption / release member includes a frame having a space in the frame and a pair of breathable covers stretched on both surfaces of the frame so as to cover the space in the frame, and the absorption / release agent is in a powder state The carbon dioxide supply device according to claim 7, wherein the carbon dioxide supply device is housed in the space inside the frame.   The air blowing means is provided in the first opening to perform the outside air feeding in the first mode, and the second air blowing is provided in the second opening to perform the outside air feeding in the second mode. The carbon dioxide supply device according to any one of claims 1 to 9, further comprising a section.   The apparatus further comprises carbon dioxide replenishing means, wherein the carbon dioxide replenishing means has a container containing a second absorption / release agent, a suction pump for sucking a gas inside the container, and an exhaust port of the suction pump. The carbon dioxide supply device according to any one of claims 1 to 10, further comprising a replenishment path connected to the inside of the use room.   The carbon dioxide supply device according to any one of claims 1 to 11, wherein the carbon dioxide utilization chamber is a greenhouse for growing plants. A method of supplying carbon dioxide to a carbon dioxide utilization chamber having a first opening and a second opening,
An absorption / release agent that causes an equilibrium reaction with absorption / release of carbon dioxide is placed on the blowing path of the blowing means,
A first step of sending outside air from the first opening to the inside of the carbon dioxide utilization chamber by the blowing means, and sending atmospheric gas in the carbon dioxide utilization chamber from the second opening;
A second step of sending outside air into the carbon dioxide utilization chamber from the second opening and sending out the atmospheric gas from the first opening by the blowing means;
The carbon dioxide supply method is characterized in that it is executed alternately and repeatedly.   14. The carbon dioxide supply method according to claim 13, wherein the absorption / release agent causes an equilibrium reaction involving absorption / release of carbon dioxide and water vapor.   The carbon dioxide supply method according to claim 14, wherein the absorption / release agent also releases water vapor when releasing carbon dioxide, and also absorbs water vapor when absorbing carbon dioxide.   The absorption / release agent is potassium carbonate, sodium carbonate, lithium carbonate, sesquipotassium carbonate, sodium sesquicarbonate, lithium sesquicarbonate, ammonium carbonate, an amine carbonate compound, or a resin in which an amine carbonate group is fixed, or a hydrate thereof. It contains, The carbon dioxide supply method of any one of Claims 13-15 characterized by the above-mentioned.   When the integrated air flow rate in each of the first and second steps becomes substantially the same as the internal volume of the carbon dioxide utilization chamber, the first and second steps are performed immediately or after a pause step in which the blowing means is suspended. The carbon dioxide supply method according to any one of claims 13 to 16, wherein switching is performed.   A replenishment preparation step of bringing air into contact with the second absorption / release agent accommodated in the container, and a replenishment step of sucking the gas inside the container with a suction pump and supplying the gas inside the carbon dioxide utilization chamber, The carbon dioxide supply method according to any one of claims 13 to 17, wherein the carbon dioxide supply method is alternately performed separately from the first and second steps.   The carbon dioxide supply method according to any one of claims 13 to 18, wherein the carbon dioxide utilization chamber is a greenhouse for growing plants.

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