JP2016054667A - Plant cultivation apparatus, and air conditioner for plant cultivation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner for a plant cultivation apparatus which is capable of bringing saturation deficit or humidity of a plant raising space within an appropriate range.SOLUTION: An air conditioner 20 is a heat-pump type air conditioner, and has a compressor 21, a heat exchanger 22 for condensation/evaporation use, an expansion valve group 23, a heat exchanger 25 for evaporation/condensation use, and a flow channel selector valve 26, which are connected circularly. The air conditioner 20 has an auxiliary dehumidifying circuit 40, and is capable of returning a part of coolant ejected from the heat exchanger 25 for evaporation/condensation use to the compressor 21 via an auxiliary heat exchanger 43 during a heating operation, by which surface temperature of the auxiliary heat exchanger 43 can be reduced and the plant raising space 3 can be dehumidified.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a plant cultivating apparatus for cultivating plants such as vegetables, fruits, grains, and florets, and an air conditioner employed in the plant cultivating apparatus. The present invention is a closed type and suitable for a plant cultivation apparatus that performs hydroponics.

Plant cultivation devices for cultivating vegetables and the like are known. The scale of the plant cultivation device varies, and there are large ones in which the entire building is a plant growing space. Such a large plant cultivation apparatus is generally called a plant factory or a crop factory.
There is also a plant cultivation device installed in the building. As for the plant cultivation apparatus installed in the building, there is one in which the entire room is a plant growing space, or an independent apparatus that is installed in the room.

In addition, there are two types of plant cultivation apparatuses, one called a solar type plant factory and one called a closed type plant factory (also called an artificial light type plant factory).
A solar-type plant factory is a kind of greenhouse that takes sunlight into the room and performs photosynthesis on plants. The solar plant factory has a ventilation window and opens and closes the window to adjust the temperature of the plant growing space.

In contrast, a closed plant factory is equipped with artificial lighting and an air conditioner, and in principle, the plant is irradiated with only the light from the artificial lighting to perform photosynthesis. The closed plant factory restricts the air flow between the plant growing space and the outside, and creates the optimal temperature environment for the plant by the air conditioner.
Patent Document 1 discloses an example of a closed plant factory.
Patent Document 2 discloses an example of a solar type plant factory. The invention disclosed in Patent Document 2 is a photosynthesis promotion system that includes a mist generator and is capable of adjusting the humidity in the plant growing space by humidifying with the mist generator.

The photosynthesis promotion system disclosed in Patent Document 2 includes a mist controller, and the mist controller is configured to set a humidity setting value with a saturation.
The photosynthesis promotion system disclosed in Patent Document 2 is applied to a greenhouse and can be said to be a solar-type plant factory. That is, the photosynthesis promotion system disclosed in Patent Document 2 is to perform photosynthesis in principle using natural light. In addition, the photosynthesis promotion system disclosed in Patent Document 2 periodically ventilates and suppresses temperature rise in the room, and is not a closed plant factory in this respect. Furthermore, the photosynthesis promotion system disclosed in Patent Document 2 does not have a cooling function. The photosynthesis promotion system disclosed in Patent Document 2 adjusts humidity by a mist generator, but does not have a dehumidifying function.

JP 2012-125196 A Japanese Patent No. 5198682

Closed plant factories use artificial light to create daytime environments. Since the artificial light source generates heat, the temperature of the plant growing space rises. For this reason, some closed plant factories have a cooling device and employ a configuration in which the cooling device is operated to lower the temperature of the plant growing space to an appropriate temperature.
Moreover, in order to create a night environment, artificial light is stopped. In this case, the temperature of the plant growing space drops. For this reason, some closed plant factories employ a configuration that includes a heating device and operates the heating device to raise the temperature of the plant growing space to an appropriate temperature.

However, many of the conventional closed plant factories do not have a function of maintaining the humidity of the plant growing space within a certain range.
Here, not only temperature but also humidity is a major factor in the success or failure of plant growth. Saturation is important as a humidity condition related to plant growth. Saturation is an index indicating how much room for water vapor can enter in air at a certain temperature and humidity, and represents the free water vapor capacity per cubic meter of air in grams. In other words, the satiety is the amount of water vapor that can be contained in the current air in grams.
More precisely, the saturation is defined by the following equation.

The plant breathes and discharges water vapor at that time, but if the current environment is small and there is no room for water vapor to be taken into the environment, the respiration of the plant is inhibited and the growth of the plant is delayed. On the contrary, it is said that there is a harmful effect when there is too much room for taking water vapor into the environment.
It is generally said that the saturation suitable for plant growth is ³ to 6 g / m ³ (gram per cubic meter).
For example, the temperature typically used for lettuce cultivation is 23 degrees Celsius in the light period (daytime environment) and 18 degrees Celsius in the dark period (nighttime environment). The relationship between relative humidity and dew point temperature in this state is as shown in the following table.

  As described above, many of the closed plant factories of the prior art do not have a function of maintaining the humidity of the plant growing space within a certain range, and the humidity and saturation of the plant growing space are likely.

Here, when the plant growing space is a daytime environment, even if it happens, the saturation is often within the allowable range, but it may be excessively dehumidified by cooling operation, and the saturation may be too large. is there.
On the other hand, when a night environment is created, the humidity of the plant growing space becomes excessively high, and the satiety tends to be excessively reduced.

  That is, many closed plant factories have a structure in which hydroponics is performed in a plant growing space. Therefore, a large amount of water is present in the plant growing space, and the area where the water and air are in contact with each other is wide. Therefore, the closed plant factory is in an environment where water is easily evaporated and water vapor is easily generated. That is, it can be said that the closed plant factory is an environment in which the humidity is likely to increase and the saturation is likely to be reduced.

When the plant growing space is a daytime environment, the artificial lighting is turned on, so the temperature of the plant growing space tends to rise due to the heat generated by the artificial lighting, and the amount of water evaporation increases. However, when the temperature of the plant growing space rises, the cooling operation is performed. As a result, the temperature of the evaporator surface falls below the dew point, and water vapor condenses on the evaporator surface and the humidity decreases. Therefore, when the plant growing space is a daytime environment, the satiety rarely exceeds the allowable range.
However, the water vapor in the plant growing space may be excessively condensed by cooling, and the saturation may be excessively increased by the cooling operation.

On the other hand, since the artificial lighting is turned off when the night environment is created, the temperature in the plant growing space tends to decrease. Therefore, heating operation is performed to compensate for the temperature drop, and the amount of water evaporation is considerably large as in the daytime environment.
However, the air conditioner is heating-operated and cannot reduce humidity. Therefore, when the night environment is created, the humidity of the plant growing space becomes excessively high, and the satiety may be excessively reduced.

  Then, this invention pays attention to the above-mentioned problem of a prior art, and makes it a subject to provide the plant cultivation apparatus and air-conditioning apparatus which can keep the saturation and humidity of plant growth space in an appropriate range.

  Invention of Claim 1 for solving an above-mentioned subject is an air conditioner for plant cultivation equipment which has a plant growth space, Comprising: Refrigerant circulation including a compressor, an expansion means, and a plurality of heat exchangers In an air conditioner that has a circuit and circulates a phase-change refrigerant in the refrigerant circulation circuit, the temperature in the plant growing space maintains a predetermined target temperature, and the amount of water vapor or humidity that can be contained in the air is predetermined. The compressor and the expansion means are controlled so as to be in a range.

  In the air conditioner in the plant cultivation apparatus of the present invention, the compressor and the expansion means are controlled so that the amount of water vapor or humidity that can be contained in the air falls within a predetermined range. Therefore, it is possible to keep the difference in plant growth space within an appropriate range.

  The invention according to claim 2 includes, as the plurality of heat exchangers, a condensation / evaporation heat exchanger, an evaporation / condensation heat exchanger, an auxiliary heat exchanger, and a flow path switching unit. The evaporator / condensation heat exchanger and auxiliary heat exchanger are arranged at a position communicating with the plant growing space, and the condensation / evaporating heat exchanger is arranged at a position not communicating with the plant growing space, It is possible to carry out a heating operation that raises the temperature of the plant and a cooling operation that lowers the temperature of the plant growth space. Reach the evaporator / condensation heat exchanger and return it to the compressor. During heating operation, let the refrigerant compressed by the compressor go from the evaporator / condensation heat exchanger through the expansion means to the condensation / evaporation heat exchanger. Return to compressor and warm During operation, it is possible to return part of the refrigerant discharged from the evaporator / condensation heat exchanger to the compressor via the auxiliary heat exchanger, thereby reducing the surface temperature of the auxiliary heat exchanger and The air conditioner for a plant cultivation device according to claim 1, wherein the air conditioning device can be dehumidified.

The air conditioner according to claim 2 is a heat pump type air conditioner.
That is, the air conditioner according to claim 2 includes a heat exchanger for condensation / evaporation and a heat exchanger for both evaporation and condensation as heat exchangers constituting the heat pump circuit. During the cooling operation, the refrigerant compressed by the compressor is returned from the condensation / evaporation heat exchanger to the evaporation / condensation heat exchanger via the expansion means and returned to the compressor. As a result, the compressed refrigerant is condensed in the condensation / evaporation combined heat exchanger, enters the evaporation / condensation combined heat exchanger through the expansion means, and lowers the surface temperature of the evaporation / condensation combined heat exchanger.
Since the evaporating / condensing combined heat exchanger is arranged at a position communicating with the plant growing space, the plant growing space is cooled by lowering the surface temperature of the evaporating / condensing combined heat exchanger. Further, the plant growing space can be dehumidified as necessary.
On the other hand, during the heating operation, the refrigerant compressed by the compressor is returned from the evaporator / condensation heat exchanger to the condenser / evaporation heat exchanger via the expansion means and returned to the compressor. As a result, the surface temperature of the evaporating / condensing heat exchanger increases. As described above, the evaporating / condensing combined heat exchanger is arranged at a position communicating with the plant growing space, so that the plant growing space is heated by increasing the surface temperature of the evaporating / condensing combined heat exchanger. .
Moreover, the air conditioner of this invention has an auxiliary heat exchanger in addition to the heat exchanger which comprises a normal heat pump circuit.
The auxiliary heat exchanger can return part of the refrigerant discharged from the evaporation / condensation heat exchanger to the compressor via the auxiliary heat exchanger and is condensed in the evaporation / condensation heat exchanger. The refrigerant can be evaporated. As a result, the surface temperature of the auxiliary heat exchanger can be lowered and the plant growing space can be dehumidified. Therefore, according to the air conditioner of the present invention, the inside of the plant growing space can be dehumidified even during the heating operation.

  According to a third aspect of the present invention, there is provided an evaporating temperature detection for detecting an evaporating temperature of the refrigerant in the auxiliary heat exchanger, wherein auxiliary expansion means is provided in a flow path connecting the heat exchanger for both evaporating and condensing and the auxiliary heat exchanger. The auxiliary expansion means is controlled so that the refrigerant evaporating temperature detected by the evaporating temperature detecting means becomes a desired temperature. The air conditioner for plant cultivation apparatus according to claim 2, is there.

  The evaporating temperature detecting means only needs to be able to detect the evaporating temperature of the refrigerant directly or indirectly. Therefore, the evaporating temperature detecting means is not limited to a structure in which a temperature sensor is inserted in the refrigerant flow path. For example, the evaporating temperature detecting means detects the surface temperature of the auxiliary heat exchanger or the piping near the auxiliary heat exchanger. It may be one that detects temperature.

  Invention of Claim 4 is a plant cultivation apparatus provided with the air conditioner for plant cultivation apparatuses in any one of Claim 1 thru | or 3.

  According to the plant cultivation apparatus of the present invention, the temperature, humidity, or saturation of the plant growing space temperature can be appropriately controlled.

  According to the air conditioner of the present invention, the saturation and humidity of the plant growing space can be within an appropriate range. Therefore, when the air conditioner of the present invention is employed, the plant grows well and an increase in yield can be expected. The same applies to the plant cultivation apparatus of the present invention, and the growth of the plant is good and an increase in yield can be expected.

It is a conceptual diagram which shows the layout of the plant cultivation apparatus of embodiment of this invention. It is an operation | movement principle figure of the air conditioner of the plant cultivation apparatus of FIG. FIG. 3 is an operation principle diagram of FIG. 2 and shows a refrigerant flow during cooling operation. FIG. 3 is an operation principle diagram of FIG. 2 and shows a refrigerant flow during heating operation. It is an operation principle figure of the air-conditioner in other embodiments of the present invention, and shows the flow of the refrigerant at the time of heating operation.

Embodiments of the present invention will be further described below.
The plant cultivation apparatus 1 of the present embodiment is called a closed plant factory, and a substantially entire area of the building 2 is a plant growing space 3.
In the plant growing space 3, shelves 5 are provided in multiple layers. An artificial illumination 6 is provided on the upper side of each shelf 5. The artificial illumination 6 is an illumination device such as an LED or a fluorescent lamp.
A cultivation pallet 7 is placed on each shelf 5. The cultivation pallet 7 is used for hydroponically cultivating crops 8 such as lettuce, and water for cultivation (not shown) is stored therein. Further, a supply pipe 10 for supplying the cultivation water to the cultivation pallet 7 and a discharge pipe for discharging the cultivation water are provided.

As described above, the plant cultivation apparatus 1 is called a closed plant factory, and ventilation inside and outside the plant growing space 3 is restricted. That is, the plant growing space 3 has a vent (not shown) communicating with the outside, but is normally closed during the light period (daytime environment). The dark period (nighttime environment) is opened to take in oxygen.
A filter is provided in the vent hole, and only air from which foreign matters, insects, and the like have been removed by the filter can enter the plant growing space 3.

Moreover, the plant cultivation apparatus 1 is provided with the air conditioner 20 shown in FIG.
The air conditioner 20 is a heat pump type air conditioner, and is formed with a main circuit 11 constituting a heat pump circuit similar to that of a known one.
The main circuit 11 is a refrigerant circulation circuit indicated by a thick line in FIG. As shown in FIG. 2, the main circuit 11 includes a compressor 21, a heat exchanger 22 for condensing / evaporating, an expansion valve group 23 (both an expansion valve for cooling and an expansion valve for heating), and heat exchange for both evaporating / condensing. And a flow path switching valve (flow path switching means) 26, which are connected in an annular shape.
That is, the compressor 21, the condenser / evaporation heat exchanger 22, the expansion valve group 23, and the evaporator / condensation heat exchanger 25 are annularly connected in this order, and the compressor 21 and the condensation / evaporation heat exchanger 25 are connected. A flow path switching valve 26 is interposed between the heat exchanger 25 and the evaporation / condensation heat exchanger 25.

The flow path switching valve 26 is a four-way valve and has four ports A, B, C, and D. The discharge side of the compressor 21 is connected to the port A, and the suction side of the compressor 21 is connected to the port B.
The port C of the flow path switching valve 26 is connected to the heat exchanger 22 for both condensation and evaporation. The port D is connected to the evaporating / condensing heat exchanger 25.
The flow path switching valve 26 can switch whether the discharge side of the compressor 21 is connected to the condensation / evaporation heat exchanger 22 or to the evaporation / condensation heat exchanger 25. When the flow path switching valve 26 is switched and the discharge side of the compressor 21 is connected to the condensation / evaporation heat exchanger 22, the evaporation / condensation heat exchanger 25 is connected to the suction side of the compressor 21. Is done. Further, when the flow path switching valve 26 is switched and the discharge side of the compressor 21 is connected to the evaporation / condensation heat exchanger 25, the condensation / evaporation heat exchanger 22 is placed on the suction side of the compressor 21. Connected.

The expansion valve group 23 includes a cooling expansion valve 30 and a heating expansion valve 31 that are expansion means. The cooling expansion valve 30 and the heating expansion valve 31 are connected in parallel. More specifically, a bypass circuit 35 that bypasses the cooling expansion valve 30 is provided, and a heating expansion valve 31 is provided in the bypass circuit 35. The connection direction of the heating expansion valve 31 is opposite to that of the cooling expansion valve 30 described above. In other words, the cooling expansion valve 30 is connected to the condensation / evaporation combined heat exchanger 22 side on the introduction side and connected to the evaporation / condensation combined heat exchanger 25 side on the discharge side, whereas the heating expansion valve 31 is The introduction side is connected to the evaporation / condensation heat exchanger 25 side, and the discharge side is connected to the condensation / evaporation heat exchanger 22 side.
An on-off valve 33 is provided in the bypass circuit 35 at a position closer to the evaporating / condensing combined heat exchanger 25 than the heating expansion valve 31. The on-off valve 33 is a solenoid valve.

The air conditioner 20 employed in the present embodiment has an auxiliary dehumidification circuit 40 as a specific configuration. The auxiliary dehumidification circuit 40 is a circuit indicated by a thin line in FIG.
The auxiliary dehumidification circuit 40 is a circuit that branches between the expansion valve group 23 of the main circuit 11 and the heat exchanger 25 for both evaporating and condensing and reaches the suction side of the compressor 21, and includes an on-off valve 41, an auxiliary expansion valve ( Auxiliary expansion means) 42 and an auxiliary heat exchanger 43. The on-off valve 41 is one of flow path switching means. The on-off valve 41 is a solenoid valve.

In the compressor 21 employed in the air conditioner 20 employed in the present embodiment, a built-in motor (not shown) is inverter-controlled, and the rotation speed can be arbitrarily changed. Therefore, the compressor 21 can adjust the compression amount of the refrigerant.
Each expansion valve is an electronic expansion valve, and the opening degree can be adjusted. That is, the cooling expansion valve 30, the heating expansion valve 31, and the auxiliary expansion valve 42 are all electronic expansion valves, and their opening degrees can be adjusted.

The air conditioner 20 employed in the present embodiment includes a main circuit evaporation temperature detection means 45 and an auxiliary circuit evaporation temperature detection means 46 as temperature detection means in the piping system. The main circuit evaporating temperature detecting means 45 and the auxiliary circuit evaporating temperature detecting means 46 are known temperature sensors such as a thermocouple and a thermistor.
The main circuit evaporating temperature detecting means 45 is provided in the vicinity of the evaporating / condensing combined heat exchanger 25 and on the compressor 21 side, and in the evaporating / condensing combined heat exchanger 25 when the air conditioner 20 is cooled. The evaporating temperature of the refrigerant is detected.
The auxiliary circuit evaporating temperature detection means 46 detects the evaporating temperature of the refrigerant in the auxiliary heat exchanger 43.

In the plant cultivation apparatus 1, the members of the air conditioner 20 are arranged in the layout shown in FIG.
That is, the plant cultivation apparatus 1 has an air conditioning duct 50 that communicates with the plant growing space 3, and the air conditioning duct 50 incorporates an evaporating / condensing combined heat exchanger 25 and an auxiliary heat exchanger 43. The air conditioning duct 50 is provided with a blower 51 so that the air conditioning duct 50 can be ventilated.
The air conditioning duct 50 described above has both ends communicating with the plant growing space 3, and forms a circulation air path between the plant growing space 3. In this embodiment, the air in the plant growing space 3 is introduced into the air conditioning duct 50 from the air inlet 53 at the lower side of the drawing, and the air that has passed through the air conditioning duct 50 passes through the air outlet 55 at the upper side of the drawing. Returned to 3.

  In this embodiment, an air temperature detecting means 56 and a humidity detecting means 57 are provided in the vicinity of the air inlet 53 of the air conditioning duct 50.

  All other members of the air conditioner 20 are in positions that do not communicate with the plant growing space 3. In particular, the heat exchanger 22 for condensing and evaporating is located outside the plant growing space 3 and does not communicate with the plant growing space 3.

Next, a control device that controls the air conditioner 20 will be described. The air conditioner 20 has a main controller 60 and electronic expansion valve controllers 61 and 62 as shown in FIG.
The main controller 60 has a display function, a setting function, and a control function. Detection signals from the air temperature detection means 56 and the humidity detection means 57 are input to the main controller 60. A control signal is output from the main controller 60 to the electronic expansion valve controllers 61 and 62.
The electronic expansion valve controller 61 receives the refrigerant evaporation temperature in the evaporating / condensing heat exchanger 25 from the main circuit evaporating temperature detecting means 45. The opening degree of the cooling expansion valve 30 and the heating expansion valve 31 is controlled by the electronic expansion valve controller 61.
The electronic expansion valve controller 62 receives the refrigerant evaporation temperature in the auxiliary heat exchanger 43 from the auxiliary circuit evaporation temperature detecting means 46. The opening degree of the auxiliary expansion valve 42 is controlled by the electronic expansion valve controller 62.

The main controller 60 has a display function, a setting function, and a control function as described above. The setting function is realized by a numeric keypad, for example, and can set a target environment in the plant growing space 3. Specifically, the target temperature of the plant growing space 3 and the target saturation can be set. The display function is a known display, and can display setting contents, current temperature, humidity, saturation, and the like.
The main controller 60 receives the detected temperature of the air temperature detecting means 56, and the compressor 21, the cooling expansion valve 30, and the heating expansion valve 31 are arranged so that the temperature in the plant growing space 3 matches the target temperature. PID controlled.

The main controller 60 has a function of storing or calculating the relationship between the evaporation temperature of the refrigerant in the evaporating / condensing heat exchanger 25 and the saturation in the plant growing space 3 during the cooling operation.
In other words, when the air conditioner 20 is in a cooling operation and the temperature in the plant growing space 3 is a specific temperature, the temperature of the refrigerant in the evaporation / condensation heat exchanger 25 is set to what temperature. The main controller 60 stores or calculates whether the saturation in the growth space 3 falls within an appropriate range.

Similarly, the main controller 60 has a function of storing or calculating the relationship between the evaporation temperature of the refrigerant in the auxiliary heat exchanger 43 during the heating operation and the saturation in the plant growing space 3.
That is, when the air conditioner 20 is heated and the temperature in the plant growing space 3 is a specific temperature, what is the temperature at which the refrigerant evaporates in the auxiliary heat exchanger 43 is set to what temperature? It is stored or calculated by the main controller 60 whether the difference is within the appropriate range.
The relationship between the evaporation temperature of the refrigerant and the saturation in the plant growing space 3 can be obtained by experiments.

In the air conditioner 20 of the present embodiment, an appropriate evaporation temperature is selected or calculated so that the saturation in the plant growing space 3 is within an appropriate range, and the signal is sent from the main controller 60 to the electronic expansion valve controller 61 and the electronic expansion valve. It is transmitted to the controller 62.
The electronic expansion valve controller 61 and the electronic expansion valve controller 62 control the opening degrees of the cooling expansion valve 30, the heating expansion valve 31, and the auxiliary expansion valve 42, and the evaporation / condensation heat exchanger 25 and the auxiliary heat exchanger are controlled. The refrigerant evaporation temperature in 43 is adjusted.

That is, the amount of dehumidification is related to the surface temperature of the heat exchanger 25 for both evaporation / condensation and the auxiliary heat exchanger 43, the surface temperature of the heat exchanger 25 for both evaporation / condensation 25 and the auxiliary heat exchanger 43, and the dew point in the current environment. The amount of dehumidification changes depending on the difference.
The surface temperatures of the evaporating / condensing heat exchanger 25 and the auxiliary heat exchanger 43 depend on the evaporating temperature of the refrigerant, and the evaporating temperature of the refrigerant is related to the opening degrees of the heating expansion valve 31 and the auxiliary expansion valve 42. That is, if the opening degree of the heating expansion valve 31 and the auxiliary expansion valve 42 is reduced, the evaporation temperature of the refrigerant decreases, the surface temperature of the evaporation / condensation heat exchanger 25 and the auxiliary heat exchanger 43 decreases, and the dehumidification amount increases. To do. Conversely, if the opening degree of the heating expansion valve 31 and the auxiliary expansion valve 42 is increased, the evaporation temperature of the refrigerant rises, the surface temperatures of the evaporating / condensing heat exchanger 25 and the auxiliary heat exchanger 43 rise, and the dehumidification amount is increased. descend. Therefore, in this embodiment, the opening degree of the heating expansion valve 31 is controlled to adjust the refrigerant evaporation temperature in the evaporation / condensation heat exchanger 25 and the auxiliary heat exchanger 43, and the dehumidification amount is adjusted to adjust the plant growth space. Adjust the saturation in 3 to an appropriate range.

Next, the function of the plant cultivation apparatus 1 of this embodiment is demonstrated centering on the air conditioner 20. FIG.
The plant cultivation apparatus 1 is provided with artificial lighting 6, and can turn on the artificial lighting 6 to create a daytime environment. Moreover, the night environment can be created by turning off the artificial lighting 6.
Furthermore, the temperature and saturation of the plant growing space 3 can be kept within a certain range by the air conditioner 20.
Although there are differences depending on the season, when the daytime environment is created, the temperature in the plant growing space 3 tends to rise due to the heat generated by the artificial lighting 6. In such a case, the air conditioner 20 is cooled.

Since the air conditioner 20 is a heat pump type air conditioner as described above, the cooling operation can be performed by switching the flow path switching valve (flow path switching means) 26.
The flow of the refrigerant during the cooling operation is as shown in FIG.
That is, the flow path switching valve 26 is switched so that the discharge side of the compressor 21 is connected to the heat exchanger 22 for both condensation and evaporation. At this time, the evaporating / condensing heat exchanger 25 is connected to the suction side of the compressor 21. Further, the on-off valve 33 provided in the bypass circuit 35 is closed to prevent the refrigerant from flowing into the heating expansion valve 31 (expansion means). Similarly, the on-off valve (flow path switching means) 41 provided in the auxiliary dehumidification circuit 40 is closed to prevent the refrigerant from flowing into the auxiliary expansion valve 42 and the auxiliary heat exchanger 43. In this state, the compressor 21 is operated.

As a result, the refrigerant pressurized by the compressor 21 is introduced into the condensation / evaporation combined heat exchanger 22 and is deprived of heat to be liquefied. The liquefied refrigerant flows into the evaporating / condensing combined heat exchanger 25 via the cooling expansion valve 30, and the refrigerant evaporates and takes heat from the surroundings. In the cooling operation, since the refrigerant does not flow through the heating expansion valve 31 (expansion means) as described above, the heating expansion valve 31 does not function.
As a result, the surface temperature of the evaporation / condensation combined heat exchanger 25 is lowered, and the temperature of the plant growing space 3 is lowered.
That is, the detected temperature of the air temperature detecting means 56 is input to the main controller 60, and the compressor 21 is inverter-controlled, so that the amount of refrigerant supplied from the compressor 21 can be increased or decreased. In this embodiment, the rotation speed of the compressor 21 is increased or decreased so that the temperature in the plant growing space 3 matches the target temperature.

During cooling operation, the refrigerant evaporating temperature in the evaporating / condensing combined heat exchanger 25 is monitored by the main circuit evaporating temperature detecting means 45 so that the saturation in the plant growing space 3 is within an appropriate range. The opening degree of the expansion valve 30 is adjusted.
As described above, when the cooling operation is performed, the water vapor in the plant growing space 3 may be excessively condensed by the cooling. According to the present embodiment, the refrigerant evaporation temperature is monitored and excessive dehumidification is prevented, so that the saturation in the plant growing space 3 can be within an appropriate range.
In order to reduce the amount of dehumidification, it is necessary to increase the refrigerant evaporation temperature, and it is necessary to reduce the difference between the current environment temperature and the surface temperature of the evaporating / condensing heat exchanger 25. Therefore, it is recommended that the evaporator / condensation heat exchanger 25 has a large contact area with air for the purpose of securing a heat exchange amount. For example, it is assumed that the evaporating / condensing combined heat exchanger 25 has the largest contact area among the condensing / evaporating combined heat exchanger 22, the evaporating / condensing combined heat exchanger 25, and the auxiliary heat exchanger 43.

Although there is a difference depending on the season, when the night environment is created, the artificial lighting 6 is turned off and the heat source disappears, so the temperature in the plant growing space 3 tends to decrease. In such a case, the air conditioner 20 is heated.
Since the air conditioner 20 is a heat pump type air conditioner as described above, the heating operation can be performed by switching the flow path switching valve (flow path switching means) 26.
The refrigerant flow during the heating operation is as shown in FIG.
That is, the flow path switching valve 26 is switched so that the discharge side of the compressor 21 is connected to the evaporation / condensation heat exchanger 25. At this time, the condensation / evaporation combined heat exchanger 22 is connected to the suction side of the compressor 21. Moreover, the on-off valve 33 provided in the bypass circuit 35 is opened, and the refrigerant is caused to flow through the heating expansion valve 31 (expansion means).
As a result, the refrigerant pressurized by the compressor 21 is introduced into the evaporation / condensation heat exchanger 25, and the surface temperature of the evaporation / condensation heat exchanger 25 increases. And the temperature of the plant growth space 3 rises.

When the temperature of the plant growing space 3 rises, evaporation of water for hydroponics advances and the satiety decreases. In such a case, the on-off valve 41 provided in the auxiliary dehumidification circuit 40 is opened, and the refrigerant flows through the auxiliary expansion valve 42 and the auxiliary heat exchanger 43.
As described above, the auxiliary dehumidification circuit 40 has a branch between the expansion valve group 23 of the main circuit 11 and the heat exchanger 25 for both evaporation and condensation. During the heating operation, liquid refrigerant flows through the portion.
That is, during the heating operation, the refrigerant pressurized by the compressor 21 is introduced into the evaporating / condensing heat exchanger 25, and heat is taken away to be liquefied. Accordingly, the refrigerant discharged from the evaporation / condensation heat exchanger 25 is in the liquid phase, and the refrigerant in the liquid phase is introduced into the auxiliary dehumidification circuit 40. The refrigerant introduced into the auxiliary dehumidification circuit 40 enters the auxiliary expansion valve 42 and the auxiliary heat exchanger 43 and evaporates to take heat away from the surroundings. As a result, the surface temperature of the auxiliary heat exchanger 43 decreases. Since the auxiliary heat exchanger 43 is provided at a position communicating with the plant growing space 3, the water vapor contained in the air in the plant growing space 3 is condensed to increase the saturation.

  During this time, the refrigerant evaporating temperature in the auxiliary heat exchanger 43 is monitored from the auxiliary circuit evaporating temperature detecting means 46, and the opening of the auxiliary expansion valve 42 is adjusted so that the saturation in the plant growing space 3 is within an appropriate range. Adjusted.

In the embodiment described above, the relationship between the evaporation temperature of the refrigerant in the evaporation / condensation heat exchanger 25 during cooling operation and the saturation in the plant growing space 3 is stored or calculated. During the cooling operation, the evaporation temperature of the refrigerant in the evaporation / condensation heat exchanger 25 is monitored, and the opening degree of the cooling expansion valve 30 is controlled so as to be an appropriate evaporation temperature.
In the embodiment described above, the relationship between the evaporation temperature of the refrigerant in the auxiliary heat exchanger 43 during the heating operation and the saturation in the plant growing space 3 is stored or calculated. Then, during the heating operation, the evaporation temperature of the refrigerant in the auxiliary heat exchanger 43 is monitored, and the opening degree of the auxiliary expansion valve 42 is controlled so as to be an appropriate evaporation temperature.

In short, in the embodiment described above, the opening degrees of the cooling expansion valve 30 and the auxiliary expansion valve 42 are feedback-controlled so that the evaporation temperature obtained by storage or calculation is obtained. It does not provide direct feedback control of humidity and humidity.
However, the present invention is not limited to this configuration, and the air conditioner 20 may be operated by directly feeding back the saturation or humidity in the plant growing space 3.

Hereinafter, as a modification of the present invention, a configuration in which the air conditioner 20 is operated by directly feeding back saturation and humidity in the plant growing space 3 will be described.
In the air conditioner 20 of the present embodiment (modified example), detection signals from the air temperature detection means 56 and the humidity detection means 57 are input to the main controller 60, and the current saturation can be calculated from these data. The main controller 60 performs PID control of the compressor 21, the cooling expansion valve 30, the heating expansion valve 31, and the auxiliary expansion valve.
That is, the detection signal of the air temperature detection means 56 is compared with the target temperature, the rotation speed of the compressor 21, the cooling expansion valve 30, and the heating expansion valve 31 are controlled, and the temperature in the plant growing space 3 is controlled. .

Further, the current saturation and the target saturation are compared, and the cooling expansion valve 30 and the auxiliary expansion valve 42 are controlled so that the dehumidification amount is appropriate.
That is, the amount of dehumidification is related to the surface temperature of the heat exchanger 25 for both evaporation / condensation and the auxiliary heat exchanger 43. The amount of dehumidification changes depending on the difference.
The surface temperatures of the evaporating / condensing heat exchanger 25 and the auxiliary heat exchanger 43 depend on the evaporating temperature of the refrigerant, and the evaporating temperature of the refrigerant is related to the opening degrees of the cooling expansion valve 30 and the auxiliary expansion valve 42. That is, if the opening degree of the cooling expansion valve 30 and the auxiliary expansion valve 42 is reduced, the evaporation temperature of the refrigerant is lowered, and the surface temperature of the evaporating / condensing heat exchanger 25 and the auxiliary heat exchanger 43 is lowered to increase the dehumidification amount. To do. Conversely, if the opening degree of the cooling expansion valve 30 and the auxiliary expansion valve 42 is increased, the evaporation temperature of the refrigerant increases, the surface temperatures of the evaporation / condensation heat exchanger 25 and the auxiliary heat exchanger 43 increase, and the dehumidification amount is increased. descend. However, if the opening degree of the cooling expansion valve 30 and the auxiliary expansion valve 42 is increased, the amount of refrigerant introduced into the evaporation / condensation heat exchanger 25 and the auxiliary heat exchanger 43 increases, so the ability to cool the air is Increase.

In the cooling operation, when the difference in the current environment is small and it is necessary to dehumidify, the surface temperature of the evaporation / condensation heat exchanger 25 is lowered by reducing the opening of the cooling expansion valve 30. On the other hand, when there is a large difference and there is no need to dehumidify, and when the temperature of the plant growing space 3 needs to be further lowered, the opening of the cooling expansion valve 30 is opened and the heat for evaporation and condensation is used. The surface temperature of the exchanger 25 is raised.
Further, during heating operation, when the difference in the current environment is small and it is necessary to dehumidify, the surface temperature of the auxiliary heat exchanger 43 is lowered by reducing the opening of the auxiliary expansion valve 42. On the other hand, if there is a large difference and it is not necessary to dehumidify, the opening of the cooling expansion valve 30 is opened to increase the surface temperature of the evaporating / condensing heat exchanger 25 or the on-off valve 41 is closed. The introduction of the refrigerant to the auxiliary heat exchanger 43 is shut off.

  In the embodiment described above, the target saturation is input to the main controller 60, but humidity may be input instead of the saturation. For example, based on the above-described Table 1, the humidity for obtaining an appropriate saturation may be examined, and the numerical value may be manually input.

  In the embodiment described above, the dedicated auxiliary expansion valve 42 is provided in the flow path leading to the auxiliary heat exchanger 43, but as shown in FIG. 5, the expansion valve group 23 and the condensation / evaporation combined heat exchanger 22 are provided. The auxiliary expansion valve 42 can be omitted by branching and connecting to the auxiliary heat exchanger 43.

DESCRIPTION OF SYMBOLS 1 Plant cultivation apparatus 3 Plant cultivation space 6 Artificial lighting 11 Main circuit (refrigerant circulation circuit)
20 Air Conditioner 21 Compressor 22 Condensation / Evaporation Combined Heat Exchanger 23 Expansion Valve Group (Expansion Means)
25 Evaporation / condensation heat exchanger 26 Channel switching valve (channel switching means)
30: Expansion valve for cooling 31: Expansion valve for heating 33: On-off valve 40: Auxiliary dehumidification circuit 41: On-off valve 42: Auxiliary expansion valve (auxiliary expansion means)
43 Auxiliary heat exchanger 46 Auxiliary circuit evaporating temperature detecting means 45 Main circuit evaporating temperature detecting means

Claims (4)

  An air conditioner for a plant cultivation apparatus having a plant growing space, having a refrigerant circulation circuit including a compressor, expansion means, and a plurality of heat exchangers, and circulating a phase-change refrigerant in the refrigerant circulation circuit In the air conditioner to be operated, the compressor and the expansion means are controlled so that the temperature in the plant growing space maintains a predetermined target temperature and the amount of water vapor or humidity that can be contained in the air falls within a predetermined range. Air conditioner for plant cultivation equipment.   As the plurality of heat exchangers, a heat exchanger for both condensation / evaporation, a heat exchanger for both evaporation / condensation, and an auxiliary heat exchanger, and further a flow path switching means, the heat exchange for both evaporation / condensation are provided. And the auxiliary heat exchanger are arranged in a position communicating with the plant growing space, and the heat exchanger for both condensation and evaporation is arranged in a position not communicating with the plant growing space, and heating operation and plant for raising the temperature of the plant growing space In the cooling operation, the refrigerant compressed by the compressor passes from the condensation / evaporation heat exchanger to the evaporation / condensation heat exchanger via the expansion means. At the time of heating operation, the refrigerant compressed by the compressor is returned from the evaporation / condensation heat exchanger through the expansion means to the condensation / evaporation heat exchanger and returned to the compressor. , Evaporation / condensation A part of the refrigerant discharged from the heat exchanger can be returned to the compressor via the auxiliary heat exchanger, and the surface temperature of the auxiliary heat exchanger can be lowered to dehumidify the plant growing space. An air conditioner for a plant cultivation apparatus according to claim 1.   An auxiliary expansion means is provided in the flow path connecting the heat exchanger for both evaporating and condensing and the auxiliary heat exchanger. The air conditioner for a plant cultivation device according to claim 2, wherein the auxiliary expansion means is controlled so that the refrigerant evaporation temperature detected in step 1 becomes a desired temperature.   The plant cultivation apparatus provided with the air conditioner for plant cultivation apparatuses in any one of Claims 1 thru | or 3.

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