Temperature control system of agricultural greenhouse

Abstract

To efficiently utilize an outside air temperature for air-conditioning, and optimally controls a culture medium temperature to increase a growth speed of field crop.SOLUTION: A temperature control system that comprises a ventilation device and a heat pump device, and controls a culture medium temperature of an agricultural greenhouse that cultivates field crops by culture medium inside has: an outside temperature sensor TH2 which detects an outside temperature; and culture medium temperature sensors TH3a, TH3b which detect a culture medium temperature; and a control part (controller 70) which controls the ventilation device and the heat pump device on the basis of detection results of the outside temperature sensor and the culture medium temperature sensors, where the control part drives the ventilation device and the heat pump device such that the culture medium temperature alternately switches a high-temperature adaptable range and a low-temperature adaptable range after the culture medium temperature is maintained in the high-temperature adaptable range and the low-temperature adaptable range for a predetermined time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature control system for an agricultural greenhouse. [Background technology]

[0002] Conventionally, a known temperature control system for an agricultural greenhouse is the temperature control system described in Patent Document 1. This temperature control system uses a heat pump device or a heater, and aims to provide an optimal growing environment for agricultural crops based on the detection results of temperature and humidity sensors inside the greenhouse. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6686492 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] However, the technology of Patent Document 1 does not efficiently use the outside air temperature for heating and cooling, so heating and cooling costs tend to be high. In addition, the technology of Patent Document 1 aims to realize an optimal growing environment for agricultural crops by appropriately controlling the temperature inside the storage, but some types of agricultural crops (e.g., mushrooms) are more susceptible to the influence of the culture medium temperature than the temperature inside the storage. For this reason, it has not been possible to sufficiently increase the growth rate of some types of agricultural crops (e.g., mushrooms).

[0005] The present invention has been made in consideration of the above circumstances, and aims to reduce heating and cooling costs by efficiently using the outside air temperature for heating and cooling, and to increase the growth rate of agricultural crops (e.g., mushrooms) by optimally controlling the culture medium temperature. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a temperature control system for an agricultural greenhouse according to the present invention is a temperature control system which includes a ventilation device and a heat pump device and controls a culture medium temperature of an agricultural greenhouse in which agricultural crops are cultivated in a culture medium inside the greenhouse, the temperature control system including an outside temperature sensor which detects an outside temperature, a culture medium temperature sensor which detects a culture medium temperature, and a control unit which controls the ventilation device and the heat pump device based on detection results of the outside temperature sensor and the culture medium temperature sensor, and when raising the culture medium temperature so that the culture medium temperature continues in a high temperature suitable range and a low temperature suitable range for a predetermined time each and then alternately switches between the high temperature suitable range and the low temperature suitable range, if the temperature detected by the outside temperature sensor is higher than a value obtained by adding a predetermined temperature to the temperature in the high temperature suitable range, the control unit drives the ventilation device for a predetermined time until the culture medium temperature reaches the high temperature suitable range or the low temperature suitable range, and if the culture medium temperature has not reached the high temperature suitable range or the low temperature suitable range even after the predetermined time has elapsed, drives the heat pump device together with the ventilation device to raise the culture medium temperature. a ventilation device that drives the ventilation system for a predetermined time until the medium temperature reaches the high temperature suitable range or the low temperature suitable range, and if the temperature detected by the outside temperature sensor is not higher than a value obtained by subtracting a predetermined temperature from the temperature of the high temperature suitable range, the ventilation device is driven for a predetermined time until the medium temperature reaches the high temperature suitable range or the low temperature suitable range, and if the medium temperature has not reached the high temperature suitable range or the low temperature suitable range even after the predetermined time has elapsed, the heat pump device is driven together with the ventilation device until the medium temperature reaches the high temperature suitable range or the low temperature suitable range, and if the temperature detected by the outside temperature sensor is not lower than a value obtained by subtracting a predetermined temperature from the temperature of the high temperature suitable range, the heat pump device is driven until the medium temperature reaches the high temperature suitable range or the low temperature suitable range. Effect of the Invention

[0007] By efficiently using the outside air temperature for heating and cooling, it is possible to reduce heating and cooling costs, and by optimally controlling the temperature of the culture medium, it is possible to increase the growth rate of agricultural crops (e.g. mushrooms). [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a temperature control system for an agricultural greenhouse according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a diagram showing an example of control of culture medium temperature. [Figure 3A] FIG. 13 is a schematic diagram showing the airflow inside the cabinet when the ventilation fan is operating at full capacity. [Figure 3B] FIG. 13 is a schematic diagram showing the airflow inside the cabinet when the ventilation fan half is in operation. [Figure 4] 1 is a flowchart for controlling the medium temperature within a high temperature compatible range. [Diagram 5] 1 is a flowchart for controlling the medium temperature within a low temperature compatible range. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an outline of a temperature control system for a shiitake mushroom cultivation house 100 as an agricultural house. This temperature control system applies temperature stimuli (high temperature stimuli and low temperature stimuli) to a medium 20 in the house 100 to promote the growth of mycelium.

[0010] A plurality of rows of shelves 10 are arranged inside the house 100. A plurality of Shiitake mushroom culture media 20 are mounted on the shelves 10.

[0011] Culture medium temperature sensors TH3a and TH3b are disposed in the shiitake mushroom culture medium 20. The culture medium temperature sensors TH3a and TH3b are connected to a controller 70 as a control unit by wire or wirelessly (BLUETOOTH, registered trademark). The culture medium temperature sensors TH3a and TH3b may be disposed in all the culture media 20, or may be disposed in one or some of the culture media 20 located near the center of the chamber.

[0012] If it is difficult to place the culture medium temperature sensors TH3a and TH3b, the measured value of the chamber temperature sensor TH1 can be simply substituted (additively or substractively corrected) as the culture medium internal temperature. In other words, it has been found that there is a temperature difference of ±2 to 3°C between the culture medium internal temperature TH3a and the chamber temperature TH1 during the temperature drop and temperature rise periods, as shown by the four vertical double-headed arrows in Figure 2.

[0013] Therefore, during the temperature decreasing period on the left side of Fig. 2, the internal medium temperature can be simply calculated by adding the internal medium temperature TH3a = internal temperature TH1 + 2 to 3°C. Also, during the temperature increasing period on the right side of Fig. 2, the internal medium temperature can be simply calculated by subtracting the internal medium temperature TH3a = internal temperature TH1 - 2 to 3°C.

[0014] A heat pump device 30 and a boiler 40 are disposed outside the house 100. The heat pump device 30 is connected to a plurality of air heat exchangers 31 inside the house. The boiler 40 is connected to a hot air duct 41 inside the house.

[0015] An exhaust fan 50 is disposed on one side wall of the house 100. An intake damper 60 is disposed on the other side wall of the house 100.

[0016] An inside-compartment temperature sensor TH1 is disposed substantially in the center of the compartment. An outside-compartment temperature sensor TH2 is disposed on the inlet side of the intake damper 60.

[0017] Fig. 2 shows an example in which the temperature inside the house 100 is controlled by the controller 70 based on the temperatures measured by the temperature sensors TH1, TH2, TH3a, and TH3b. The vertical axis of Fig. 2 represents temperature, and the horizontal axis represents time.

[0018] Temperature control was performed continuously for 24 hours from 12:36 on March 1, 2023 to 12:36 the next day (March 2, 2023). The first was high temperature control (first half) in which the internal temperature of the medium TH3a was controlled at around 20°C. This high temperature control (first half) continued for 6 hours.

[0019] During the first half of high temperature control (first half), the inside temperature TH1 was around 20°C (±3°C) and the outside temperature TH2 was 14°C, but as the end of high temperature control (first half) approached, the inside temperature TH1 and the outside temperature TH2 began to drop. This is due to the influence of sunset. Strong heating is used during the first half of high temperature control (first half) (until 16:00), but weak heating is used in the second half (after 16:00) in preparation for low temperature control.

[0020] 3A and 3B, the ventilation fan 50 is operated and the intake damper 60 is opened. Heating by the heat pump device 30 (heat pump heating) is also performed.

[0021] The set temperature of the heat pump unit 30 can be set to 20° C. By actively introducing outside air into the storage unit in this manner, energy saving of the heat pump unit 30 can be achieved.

[0022] In the weak heating mode, the ventilation fan 50 is stopped and the intake damper 60 is closed. Also, weak heating is performed by the heat pump device 30.

[0023] In the weak heating mode, the set temperature of the heat pump device 30 can be temporarily set to, for example, 5° C. This allows the medium internal temperature TH3a to be quickly achieved at approximately 10° C. After the medium internal temperature TH3a reaches approximately 10° C., the set temperature of the heat pump device 30 can be returned from 5° C. to 10° C.

[0024] After the high temperature control (first half), low temperature control will be implemented. This low temperature control will continue for 12 hours until sunrise the next day (March 2nd).

[0025] In this low-temperature control, the set temperature of the heat pump device 30 is maintained at 10° C. (low heating), and the culture medium temperature is controlled to around 10° C. In the latter half of the low-temperature control, the outside temperature TH2 drops to about 5° C., but the inside temperature TH1 remains relatively stable at about 8° C. even with "no heating or cooling." Therefore, energy savings in the heat pump device 30 can be achieved.

[0026] Immediately after sunrise (6:36), the inside temperature TH1 and the outside temperature TH2 rise sharply. The temperature inside the medium TH3a also rises, but the rate of increase is slow.

[0027] Therefore, strong heating is performed to bring the culture medium internal temperature TH3a to the high temperature control (second half) as quickly as possible. In this strong heating, the ventilation fan 50 is operated and the intake damper 60 is opened as shown in Figures 3A and 3B.

[0028] Heating (hea-pump heating) is also performed by the heat pump device 30. By actively introducing outside air into the refrigerator in this manner, it is possible to quickly transition to high temperature control (later half), and energy saving of the heat pump device 30 can also be achieved.

[0029] The operation of the ventilation fans 50 can be selected from either full operation, in which two ventilation fans 50 are operated and two intake dampers 60 are fully opened as shown in Fig. 3A, or half operation, in which only one ventilation fan 50 is operated and only one intake damper 60 is fully opened as shown in Fig. 3B. When the temperature TH3a inside the medium approaches around 20°C (suitable high temperature range), it is possible to switch from full operation to half operation.

[0030] Continuous full or half operation causes strong air to hit a specific part of the culture medium 20 (the part of the culture medium 20 near the intake damper 60) for a long period of time. This causes a sudden drop in humidity in the culture medium 20, adversely affecting the growth of the shiitake mushrooms. Therefore, it is desirable to limit the continuous time of full or half operation to within a specified time, or to limit the opening of the intake damper 60 continuously or intermittently.

[0031] In the case of half operation, it is desirable to alternate the airflow inside the chamber between diagonal airflow 1 and diagonal airflow 2 at predetermined intervals, as shown by the solid and dashed arrows in Figure 3B. This makes it possible to prevent strong air from hitting a particular culture medium 20 for a long period of time, and also makes it possible to make the temperature distribution inside the chamber uniform.

[0032] Note that it is desirable to arrange the in - store temperature sensor TH1, the air - conditioner sensor TH1a, and the heating sensor TH1b at the location where the diagonal airflows 1 and 2 cross. This allows for accurate measurement of the temperature inside the storehouse.

[0033] ● High - temperature control The high - temperature control shown in FIG. 2 of the culture medium 20 can be performed according to the flowchart in FIG. 4. This flowchart shows the control content of the controller 70 in FIGS. 1, 3A, and 3B.

[0034] The temperatures measured by the culture - medium temperature sensors TH3a and TH3b are defined as the internal culture - medium temperature TH3a and the surface culture - medium temperature TH3b. The culture - medium temperature sensor TH3a is arranged inside the culture medium 20, and the culture - medium temperature sensor TH3b is arranged on the surface of the culture medium 20. The surface culture - medium temperature TH3b is used for monitoring and not for temperature control in high - temperature control and low - temperature control. Note that it is also possible to use the surface culture - medium temperature TH3b instead of the internal culture - medium temperature TH3a.

[0035] First, it is determined whether the internal culture - medium temperature TH3a is within the high - temperature range (17°C < TH3a < 23°C) (step S1). If the internal culture - medium temperature TH3a is not within the high - temperature range (17°C < TH3a < 23°C), it is determined whether to raise the temperature of the internal culture - medium temperature TH3a (step S2). If TH3a ≤ 17°C, the process proceeds to step S3. If 23°C ≤ TH3a, the process proceeds to step S14.

[0036] When raising the temperature and the outside - storehouse temperature TH2 is α°C or more higher than the internal culture - medium temperature TH3a, the exhaust fan is turned on to introduce warm outside air into the storehouse for energy conservation (step S3 ⇒ S4). At this stage, neither hypone heating nor boiler heating is performed yet. α°C can be set to any value, but here it is set to α°C = 1°C (the same in FIG. 5).

[0037] The introduction of outside air by the exhaust fan continues until the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C). When the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C), the exhaust fan is stopped (step S7).

[0038] However, if the internal temperature TH3a of the medium does not reach the high-temperature range (17°C < TH3a < 23°C) even after continuously introducing outside air for 1 hour, proceed from step S5 to step S10 and perform hypone heating along with the introduction of outside air. Then, when the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C), the exhaust fan and the hypone are stopped (step S7). The starting points of "1 hour elapsed?" in step S5 and "2 hours elapsed?" in step S9 are the time of judgment in step S3.

[0039] In the case of temperature increase, when the outside temperature TH2 outside the warehouse is not α°C or more higher than the internal temperature TH3a of the medium, that is, when the outside air temperature cannot be used for temperature increase, move from step S3 ⇒ S9 ⇒ S10 and perform hypone heating. The exhaust fan is OFF.

[0040] The hypone heating continues until the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C). When the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C), the hypone heating is stopped (step S7).

[0041] If the internal temperature TH3a of the medium does not reach the high-temperature range (17°C < TH3a < 23°C) even after continuously performing hypone heating for 2 hours, proceed from step S9 to step S12 and perform boiler heating along with the hypone heating. Then, when the internal temperature TH3a of the medium reaches the high-temperature range (17°C < TH3a < 23°C), the hypone heating and the boiler heating are stopped (step S7).

[0042] In the case of not increasing the temperature (decreasing the temperature), when the outside temperature TH2 outside the warehouse is α°C or more lower than the internal temperature TH3a of the medium, turn on the exhaust fan and introduce cold outside air into the warehouse for energy saving (step S14 ⇒ S15). At this stage, hypone cooling is not performed yet.

[0043] The introduction of outside air by the exhaust fan continues until the internal temperature TH3a of the medium reaches the high temperature range (17°C < TH3a < 23°C). When the internal temperature TH3a of the medium reaches the high temperature range (17°C < TH3a < 23°C), the exhaust fan is stopped (step S7).

[0044] However, if the internal temperature TH3a of the medium does not reach the high temperature range (17°C < TH3a < 23°C) even after continuously introducing outside air for 1 hour, proceed from step S16 to step S18 and perform hypone cooling together with the introduction of outside air. Then, when the internal temperature TH3a of the medium reaches the high temperature range (17°C < TH3a < 23°C), the exhaust fan and hypone cooling are stopped (step S7). The starting point of "1 hour elapsed?" in step S16 is the time of judgment in step S14.

[0045] When cooling down and the outside temperature TH2 outside the warehouse is not α°C or more lower than the internal temperature TH3a of the medium, that is, when the outside air temperature cannot be used for cooling, move from step S14 ⇒ S18 and perform hypone cooling. The exhaust fan is OFF.

[0046] Hypone cooling continues until the internal temperature TH3a of the medium reaches the high temperature range (17°C < TH3a < 23°C). When the internal temperature TH3a of the medium reaches the high temperature range (17°C < TH3a < 23°C), hypone cooling is stopped (step S7). The above temperature control is continuously performed unless "temperature control stop" is selected in step S8.

[0047] ● Low-temperature control The low-temperature control shown in FIG. 2 of the medium 20 can be performed according to the flowchart of FIG. 5. This flowchart shows the control content of the controller 70 in FIGS. 1, 3A, and 3B.

[0048] First, it is determined whether the internal temperature TH3a of the medium is in the low temperature range (7°C < TH3a < 13°C) (step S21).

[0049] When the internal temperature TH3a of the medium is not in the low-temperature appropriate range, it is determined whether to raise the temperature of the internal temperature TH3a of the medium (step S22). If TH3a ≤ 7°C, the process proceeds to step S23. If 13°C ≤ TH3a, the process proceeds to step S31.

[0050] When raising the temperature and the outside temperature TH2 outside the storage is α°C or more higher than the internal temperature TH3a of the medium, turn on the exhaust fan to introduce warm outside air into the storage for energy saving (step S23 ⇒ S24). At this stage, neither the heat pump heating nor the boiler heating is performed yet.

[0051] The introduction of outside air by the exhaust fan continues until the internal temperature TH3a of the medium reaches the low-temperature appropriate range (7°C < TH3a < 13°C). When the internal temperature TH3a of the medium reaches the low-temperature appropriate range (7°C < TH3a < 13°C), stop the exhaust fan (step S27).

[0052] However, if the internal temperature TH3a of the medium does not reach the low-temperature appropriate range (7°C < TH3a < 13°C) even after continuously introducing outside air for 1 hour, proceed from step S25 to step S29 to perform heat pump heating together with the introduction of outside air. Then, when the internal temperature TH3a of the medium reaches the low-temperature appropriate range (7°C < TH3a < 13°C), stop the exhaust fan and the heat pump (step S27). The starting point of "1 hour elapsed?" in step S25 is the time of judgment in step S23.

[0053] When raising the temperature and the outside temperature TH2 outside the storage is not α°C or more higher than the internal temperature TH3a of the medium, that is, when the outside air temperature cannot be used for raising the temperature, move from step S23 ⇒ S29 to perform heat pump heating. The exhaust fan is OFF.

[0054] The heat pump heating continues until the internal temperature TH3a of the medium reaches the low-temperature appropriate range (7°C < TH3a < 13°C). When the internal temperature TH3a of the medium reaches the low-temperature appropriate range (7°C < TH3a < 13°C), stop the heat pump heating (step S27).

[0055] When not increasing the temperature (when decreasing the temperature) and the outside temperature TH2 is α °C or more lower than the internal temperature TH3a of the medium, the exhaust fan is turned on to introduce cold outside air into the chamber for energy saving (step S31 ⇒ S32). At this stage, hypone cooling is not performed yet.

[0056] The introduction of outside air by the exhaust fan continues until the internal temperature TH3a of the medium reaches the low temperature range (7 °C < TH3a < 13 °C). When the internal temperature TH3a of the medium reaches the low temperature range (7 °C < TH3a < 13 °C), the exhaust fan is stopped (step S27).

[0057] However, if the internal temperature TH3a of the medium does not reach the low temperature range (7 °C < TH3a < 13 °C) even after continuously introducing outside air for 1 hour, proceed from step S23 to step S35 to perform hypone cooling together with the introduction of outside air. Then, when the internal temperature TH3a of the medium reaches the low temperature range (7 °C < TH3a < 13 °C), the exhaust fan and hypone cooling are stopped (step S27). The starting point of "1 hour elapsed?" in step S33 is the time of judgment in step S31.

[0058] When decreasing the temperature and the outside temperature TH2 is not α °C or more lower than the internal temperature TH3a of the medium, that is, when the outside air temperature cannot be used for temperature reduction, move to step S31 ⇒ S35 to perform hypone cooling. The exhaust fan is OFF.

[0059] Hypone cooling continues until the internal temperature TH3a of the medium reaches the low temperature range (7 °C < TH3a < 13 °C). When the internal temperature TH3a of the medium reaches the low temperature range (7 °C < TH3a < 13 °C), hypone cooling is stopped (step S27). The above temperature control is continuously performed unless "temperature control stopped" is set in step S28.

[0060] As described above, the present invention has been specifically described based on the embodiments. However, it goes without saying that the present invention is not limited to the above embodiments and can be variously modified within the scope of the technical idea described in the claims.

Explanation of Reference Numerals

[0061] 10: Shelf for storing culture medium 20: Culture medium for shiitake mushrooms 30: Heat pump device 31: Air heat exchanger 40: Boiler 41: Hot air duct 50: Exhaust fan (ventilation device) 60: Intake damper (ventilation device) 70: Controller (control unit) TH1: Internal temperature sensor TH1a: Interior air conditioner sensor TH1b: Interior heating sensor TH2: External temperature sensor TH3a, TH3b: Culture medium temperature sensor 100: Shiitake mushroom cultivation house

Claims

1. A temperature control system that includes a ventilation device and a heat pump device and controls the temperature of a medium in an agricultural greenhouse in which agricultural crops are grown, the temperature control system comprising: The present invention relates to a heat pump device and a heat pump apparatus, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a high-temperature range and a low-temperature range, and more particularly to a heat pump device and a heat pump apparatus that are adapted to heat a culture medium in a low-temperature range and a high-temperature range and more particularly to a heat pump device that is adapted to heat a culture medium in a low ... When raising the culture medium temperature, if the temperature detected by the external temperature sensor is higher than a value obtained by adding a predetermined temperature to the temperature in the high temperature range, the ventilation device is driven for a predetermined time until the culture medium temperature reaches the high temperature range or the low temperature range, and if the culture medium temperature has not reached the high temperature range or the low temperature range even after the predetermined time has elapsed, the heat pump device is driven together with the ventilation device until the culture medium temperature reaches the high temperature range or the low temperature range, and if the temperature detected by the external temperature sensor is not higher than a value obtained by adding a predetermined temperature to the temperature in the high temperature range, the heat pump device is driven until the culture medium temperature reaches the high temperature range or the low temperature range, When lowering the culture medium temperature, if the temperature detected by the outside temperature sensor is lower than a value obtained by subtracting a predetermined temperature from the temperature in the high temperature range, the ventilation device is driven for a predetermined time until the culture medium temperature reaches the high temperature range or the low temperature range, and if the culture medium temperature has not reached the high temperature range or the low temperature range even after the predetermined time has elapsed, the heat pump device is driven together with the ventilation device until the culture medium temperature reaches the high temperature range or the low temperature range, and if the temperature detected by the outside temperature sensor is not lower than a value obtained by subtracting a predetermined temperature from the temperature in the high temperature range, the heat pump device is driven until the culture medium temperature reaches the high temperature range or the low temperature range. A temperature control system comprising:

2. The agricultural house is provided with a boiler device for heating, 2. The temperature control system of claim 1, wherein, when raising the culture medium temperature, if the temperature detected by the external temperature sensor is not higher than a value obtained by adding a predetermined temperature to the temperature in the high temperature suitable range, the heat pump device is driven for a predetermined time until the culture medium temperature reaches the high temperature suitable range or the low temperature suitable range, and, if the culture medium temperature has not reached the high temperature suitable range or the low temperature suitable range even after the predetermined time has elapsed, the boiler device is driven together with the heat pump device until the culture medium temperature reaches the high temperature suitable range or the low temperature suitable range.

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