Saturation deficit control device

Abstract

To provide an inexpensive humidity deficit controlling device that can perform precise humidity deficit control of an objective space by using a low pressure humidifier.SOLUTION: A seasonal pattern is determined from solar irradiation and temperature (Fig. 3a), and a threshold value is determined on the basis of a difference between a current humidity deficit and a preset humidity deficit and a determined seasonal pattern (Fig. 3b, S3). In the case where an output value is smaller than the threshold value after stopping a mist 7 for the shortest OFF time (S2), OFF time is additionally continued (S4, S5), and the mist 7 is operated only by a fixed ON time to perform humidification only when the output value exceeds the threshold value (S4, S8). Because mist is controlled in a direction of limiting spray time, humidity deficit control can be appropriately performed without occurrence of excessive leaf wet on field crop even if a low-cost low pressure humidifier which sprays in a drizzle-like state with large particle diameters is adopted.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a saturation deficit control device that controls a humidifier to set the saturation deficit of a target space to a desired value, and in particular to a saturation deficit control device that can use a low-cost low-pressure humidifier that uses low-pressure water from a water pipe or the like, and that can control the humidifier in an optimal manner corresponding to the season and actual environmental conditions. [Background technology]

[0002] Patent Document 1 below discloses an invention related to a saturation deficit control device that generates multiple types of mists with different water contents using a single spray device and controls the saturation deficit in a greenhouse so that it quickly reaches a target value. This saturation deficit control device is installed in a cultivation greenhouse and includes a spray device 2, a measuring device 3, and a control device 4. The spray device 2 includes a sprayer body 21, a liquid supply pipe 22, a flow rate adjustment valve 23, a compressor 24, and a gas supply pipe 25. The sprayer body 21 includes a substantially bullet-shaped main body 210, a gas introduction port 211 formed on the side of the main body 210, a venturi portion 212 which is a fine hole penetrating the main body 210 in the longitudinal direction, a spray portion 213 provided at the tip of the main body 210, and a liquid introduction port 214 provided at the base end of the main body 210. Note that the reference numerals assigned to the components in the above description are those used in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-216885 Summary of the Invention [Problem to be solved by the invention]

[0004] The saturation deficit control device disclosed in Patent Document 1 is expensive due to the use of multiple nozzles. Furthermore, the sprayer used cannot be digitally turned on and off; instead, the control method increases the amount of liquid sent to the sprayer when the saturation deficit is high and decreases the amount of liquid sent to the sprayer when the saturation deficit is low. This makes it difficult to precisely control the saturation deficit, such as precisely matching the actual saturation deficit to the target saturation deficit. However, because the range of saturation deficit suitable for photosynthesis is narrow, precise control of the humidification amount is required. In particular, excessive humidification can cause the surfaces of leaves and fruits to become wet, which can lead to disease. Conversely, low humidification and prolonged dryness or sudden dryness can cause water stress, causing plants to close their stomata as a defensive response to water stress. Stomatal closure prevents photosynthesis and affects plant growth. Therefore, precise control of the humidification amount is important for plant growth.

[0005] The present invention has been made in consideration of the problems with the conventional technology described above, and aims to provide a saturation deficit control device that can be retrofitted to a spray device already installed in a target space, in particular a low-cost low-pressure humidifier that uses tap water, etc., and that can perform precise saturation deficit control to appropriately humidify the target space and allow plants to properly photosynthesize. [Means for solving the problem]

[0006] The saturation deficit control device according to claim 1 comprises: Operate the humidifier so that the current vapor pressure deficit in the target space is equal to the set vapor pressure deficit. Take control A saturation deficit control device, When the control is started, First, stop the humidifier for the shortest OFF time. 、 the After that, an output value indicating the stop time of the humidifier is calculated, and if the output value does not exceed a threshold value, the stop of the humidifier is continued. The procedure for adding OFF time is repeated as long as it is within the control time. Only when the output value exceeds the threshold value, the humidifier is operated for a fixed ON time. If it is within the control time, the humidifier is stopped for the shortest OFF time, and then the procedure for the additional OFF time is repeated.It is characterized by having a control means.

[0007] The saturation deficit control device according to claim 2 is the saturation deficit control device according to claim 1, The control means a storage unit that stores the set vapor pressure deficit and a plurality of seasonal patterns; a vapor pressure deficit calculation unit that calculates the current vapor pressure deficit using the temperature and humidity of the target space; a control unit that calculates the threshold value based on the temperature and solar radiation of the target space, the deviation between the current vapor pressure deficit and the set vapor pressure deficit, and the seasonal pattern; It is characterized by having: The saturation deficit control device according to claim 3 is the saturation deficit control device according to claim 2, CO 2 CO measured by the monitor 2 CO concentration must not fall below the lower limit. 2 A saturation deficit control device for operating a generator, When the control is started, the control means The amount of solar radiation is greater than the control stop solar radiation amount, the current vapor pressure deficit is equal to or greater than the lower limit value and equal to or less than the upper limit value, and 2 When the concentration is equal to or lower than the lower limit, 2 Control the operation of the generator, The CO 2 If the concentration is not above the upper limit, 2 Continue operating the generator, but 2 When the concentration is equal to or higher than the upper limit, the operational control is continued within the control time. The saturation deficit control device according to claim 4 is the saturation deficit control device according to any one of claims 1 to 3, The humidifier is characterized in that it is a low-pressure humidifier that sprays a drizzle-like mist using low-pressure water such as water from a water pipe. [Effects of the Invention]

[0008] According to the saturation deficit control device described in claim 1, the humidifier is always stopped for the shortest OFF time after control begins. If the calculated output value does not exceed the threshold value, the humidifier continues to be stopped. Only if the output value exceeds the threshold value, the humidifier is operated for a fixed ON time. This controls the humidifier to limit the spray time, preventing the saturation deficit from becoming too small. When low-cost low-pressure humidifiers using low-pressure water from water pipes or other sources are used to control saturation deficits in greenhouses, the sprayed mist tends to be drizzly and large in particle size, making it prone to wetting crops. However, this saturation deficit control device can appropriately limit the spray time, allowing for proper saturation deficit control in the target space without excessive leaf wetting, even with such low-cost humidifiers. For example, excessive leaf wetting can cause water droplets on leaves to form lenses, resulting in leaf burn.

[0009] According to the vapor deficit control device recited in claim 2, the current vapor deficit is calculated using the temperature and humidity of the target space, the corresponding seasonal pattern is determined from the temperature and solar radiation of the target space, and a threshold value serving as the basis for determining whether or not to stop the humidifier can be determined based on the deviation between the current vapor deficit and the set vapor deficit and the determined seasonal pattern. As a result, the vapor deficit of the target space can be controlled in a preferable manner suited to the season, allowing plants in the target space to properly perform photosynthesis. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an overall configuration diagram of a saturation deficit control device according to an embodiment; [Figure 2] 4 is a graph showing a control pattern of the saturation deficit determined by a set time and a set saturation deficit set in the saturation deficit control device of the embodiment. [Figure 3] 1A and 1B are diagrams showing control data set in a saturation deficit control device of an embodiment, in which FIG. 1A shows table data for determining a seasonal pattern from the relationship between temperature and solar radiation, and FIG. 1B shows an example of table data for determining a threshold value based on the difference between the current saturation deficit and the set saturation deficit, and the seasonal pattern. [Figure 4] 4 is a flowchart showing a control procedure of a low-pressure mist mode in the saturation deficit control device of the embodiment. [Figure 5] 3 is a flowchart showing a control procedure in a CO2 control mode in the saturation deficit control device of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a saturation deficit control device of the present invention will be described with reference to FIGS. First, the overall configuration of the saturation deficit control device 1 will be described. As shown in Fig. 1, this saturation deficit control device 1 includes a sensor group S that acquires environmental data of the target space, a control means C that calculates an output value using the environmental data sent from the sensor group S, preset control data, and control data that is changed or set during control, and a controlled device M such as a humidifier (abbreviated as "mist" 7) that is controlled by the output value sent from the control means C and is directly involved in adjusting the saturation deficit. The control means C also includes an external device 20 and an alarm device 21 that outputs an alarm for a specific control item. too It is designed to be controllable.

[0012] The target space for which the saturation deficit control device 1 performs saturation deficit control is, for example, the inside of an agricultural greenhouse. The control means C of the saturation deficit control device 1 detects the environmental conditions inside the agricultural greenhouse using a sensor group S, and operates controlled equipment M such as a mister with an output value calculated based on environmental data etc. sent from the sensor group S, thereby controlling the saturation deficit inside the agricultural greenhouse and performing saturation deficit control to create a humidity environment suitable for plants.

[0013] 1, the sensor group S includes a thermo-hygrometer 2, a solar radiation sensor 3, and a CO2 monitor 4. The thermo-hygrometer 2 measures the temperature and relative humidity (also simply called "humidity") of the target space, the solar radiation sensor 3 measures the amount of solar radiation, and the CO2 monitor 4 measures the CO2 concentration, and each outputs the measurement results to the control means C.

[0014] As shown in FIG. 1, the control means C has a sequencer 5 and a relay 6. The sequencer 5 receives inputs of temperature and humidity from the thermo-hygrometer 2, the amount of solar radiation from the solar radiation sensor 3, and the CO2 concentration from the CO2 monitor 4. The structure and operation of the sequencer 5, which is a key part of the control means C, will be described in detail later. The sequencer 5 outputs an ON / OFF signal to the relay 6 according to the calculated output value. The relay 6 operates the controlled device M, external device 20, and alarm device 21, which are installed in the target space, using the ON / OFF signal, respectively.

[0015] As shown in Fig. 1, the control target devices M operated by the control means C include a mist 7, a CO2 generator 8, an external device 20, and an alarm device 21. These control target devices M are ON / OFF controlled by an ON / OFF signal sent from a relay 6 of the control means C. The mist 7 is controlled in a basic control mode, which will be described later with reference to Fig. 7, and the CO2 generator 8 is controlled in a CO2 control mode, which will be described later with reference to Fig. 8.

[0016] The external device 20 shown in FIG. 1 is a device that is operated by an ON / OFF signal output from the control means C, and includes, for example, a dehumidifying device, a curtain opening / closing device, an exhaust fan, a skylight opening / closing device, etc., installed in an agricultural greenhouse.

[0017] 1 can issue alarms such as a high temperature alarm, a low temperature alarm, a dryness alarm, a sudden rise in saturation deficit alarm, and an excessive spray alarm. These external devices 20 and alarm devices 21 are ON / OFF controlled by an ON / OFF signal sent from a relay 6 of the control means C, either in synchronization with or asynchronously with the result of saturation deficit control, which will be described later. Note that the types and contents of alarms other than those mentioned above, as well as the sudden rise in saturation deficit alarm and the excessive spray alarm that are issued based on the result of saturation deficit control, will be explained again after the explanation of saturation deficit control.

[0018] Next, the structure of the sequencer 5 of the control means C and the saturation deficit control will be described. 1, the sequencer 5 has a memory unit 10 in which data for control is set, a vapor pressure deficit calculation unit 11 that calculates the vapor pressure deficit of the target space based on environmental data from the sensor group S, a control unit 12, and a setting unit 13. The control unit 12 selects either the low-pressure mist mode or the basic control mode to execute control.

[0019] The low-pressure mist mode is a mode for using low-pressure water such as tap water. After initially stopping the mist 7 for the shortest OFF time, a PID calculation is performed based on the data in the memory unit 10 and environmental data from the sensor group S to calculate an output value indicating the time (stop time) to stop the mist 7. If the output value does not exceed a threshold, the mist 7 continues to be stopped and the stop time is extended. Only if the output value exceeds the threshold is the mist 7 operated for a fixed ON time. The basic control mode is a control mode in which a PID calculation is performed based on the data in the memory unit 10 and environmental data from the sensor group S to calculate an output value indicating the time (operation time) to operate the mist 7. If the output value is greater than the threshold, the mist 7 is operated for the shortest ON time, and then the spray time is extended according to the output value. Details of the low-pressure mist mode and the basic control mode will be described later.

[0020] In the PID calculation described above, the output value calculated by the control unit 12 is calculated in units of 0.1 seconds. For example, an output value of 50 means that the mist 7 is stopped for 5 seconds, and by comparing this output value with a threshold value, the mist 7 can be stopped for an additional period in addition to the shortest OFF time, thereby suppressing humidification.

[0021] The setting unit 13 is an input means for selecting the control mode described above, setting various setting values ​​necessary for control, and inputting other input items directly or by selection, but it may also serve as a display unit for displaying input or set setting values, current and past environmental data, current and past control states, etc.

[0022] The vapor deficit calculation unit 11 calculates the vapor deficit of the target space based on the temperature and humidity data sent from the thermo-hygrometer 2.

[0023] As will be explained below, various data necessary for the control unit 12 to perform appropriate saturation deficit control are set in the memory unit 10. First, in order to properly PID control the saturation deficit in the target space according to a time schedule corresponding to sunrise and sunset, an appropriate control pattern for the saturation deficit, determined by the geographical location and season of the target space, is set in the memory unit 10. Figure 2 is an example of a graph showing such a control pattern, which becomes the target of control by the control means C. The control data to be stored in the memory unit 10 to determine such a control pattern include at least the set saturation deficit and the set time.

[0024] The set saturation deficit shown on the vertical axis of the graph in Fig. 2 is the initial saturation deficit, which is the initial saturation deficit when the control unit 12 starts saturation deficit control, and the maximum saturation deficit, which is the maximum value of the saturation deficit during the saturation deficit control time. These set saturation deficits are the target values ​​for saturation deficit control by PID control. Generally, rather than leaving the saturation deficit constant, gradually increasing it makes it easier for the stomata of plants to open and promotes photosynthesis. Therefore, the initial saturation deficit should be set to an ideal saturation deficit of 3 to 6 (g / m 3 ), and the maximum saturation deficit is set to be larger than the initial saturation deficit, but it is set to a slightly dry 9 (g / m 3 It is preferable to control the saturation deficit to gradually increase from the initial saturation deficit and maintain a constant value after it reaches the maximum saturation deficit.

[0025] The set times shown on the horizontal axis of the graph in Figure 2 are the control start time, which is the time when the control unit C starts saturation deficit control, the maximum time when the saturation deficit reaches its maximum, and the control end time when saturation deficit control ends. Photosynthesis occurs from sunrise to sunset, but photosynthesis is most active in the morning. Photosynthetic activity increases from morning to noon (midday). However, photosynthetic activity does not suddenly decrease after noon. Therefore, it is considered preferable to allow a margin and control the saturation deficit to increase from the morning, when photosynthesis is most active, until about two hours after noon, when solar radiation is relatively high, until the maximum saturation deficit is reached. Furthermore, by delaying the time when the saturation deficit reaches its maximum until after midday (midday), the increase in the set saturation deficit can be made more gradual. As an example of the time control of saturation deficit described above, the control start time can be set to sunrise, the maximum time can be set to about two hours after midday (midday), and the control end time can be set to sunset. These times vary depending on the geographical location of the target space and the season, and are therefore manually set in storage unit 10 by the user before control is performed. For example, in Yamagata City, in July, the sunrise time (control start time) is between approximately 4:19 and 4:39, the noon time (time when the maximum value is reached) is between approximately 11:42 and 11:45, and the sunset time (control end time) is between approximately 19:06 and 18:50. However, even in the same Yamagata City, in November, the sunrise time (control start time) is between approximately 6:04 and 6:35, the noon time (time when the maximum value is reached) is between approximately 11:22 and 11:27, and the sunset time (control end time) is between approximately 16:40 and 16:19. Data for the set time corresponding to such a combination of geographical location and date (season) may be stored in advance in the storage unit 10, and the set time may be automatically set by the calendar function and location specification. The calendar function can be realized by providing the sequencer 5 with a calendar date management unit that can automatically update calendar date data indicating the current date and month and output the calendar date as necessary. The geographical location can be specified by providing the sequencer 5 with an input unit that can input geographical location specification information by any method, such as character input on the screen or selection from a list.

[0026] Next, the memory unit 10 stores control data necessary for determining a threshold value, which is a reference value for determining whether to continue stopping the mist 7 after stopping it for the shortest OFF time after control starts, or to operate the mist 7 to spray for a fixed ON time (10 seconds, for example, in this embodiment). This threshold value is appropriately determined depending on the difference between the current vapor deficit and the set vapor deficit, and the combination of the season. If the output value by PID control output by the control unit 12 is smaller than this threshold value, the control unit 12 continues to stop the mist 7 after the shortest OFF time. Figure 3 is a schematic table showing the control data set in the memory unit 10 and that can be selected and set as needed by the setting unit 13.

[0027] Figure 3(a) shows data for determining seasonal patterns (1) to (5) based on the combination of solar radiation (vertical column) and temperature (horizontal column) in the target space. Seasonal patterns (1) and (2) indicate environmental conditions with low solar radiation and low temperature, which are common in winter. Seasonal patterns (4) and (5) indicate environmental conditions with high solar radiation and high temperature, which are common in summer. Seasonal pattern (3) indicates an intermediate environmental condition. Note that even in winter, if solar radiation is high, the temperature inside the greenhouse will rise, so seasonal pattern (4) may be applied. Furthermore, if the temperature is below 15°C, saturation deficit control is not performed.

[0028] Figure 3(b) shows the seasonal patterns (1) to (5) ("Pattern" in the vertical column) determined in Figure 3(a) and the deviation between the set saturation deficit and the current saturation deficit ("Difference from set saturation deficit (g / m 3 )") is data for the threshold value (0 to 56) that is determined by a combination of the threshold value X and the threshold value Y). The deviation between the set saturation deficit and the current saturation deficit is divided into three ranges by the boundary values ​​X and Y, so the determined threshold value is 15. Note that the user can arbitrarily change the boundary values ​​X and Y using the setting unit 13 depending on the dry / humid condition of the target space and special seasonal conditions, so that detailed saturation deficit control can be achieved.

[0029] According to the data shown in Figure 3(b), for example, seasonal pattern (1) has a high threshold value of 32 to 56 depending on the difference between the current vapor pressure deficit and the set vapor pressure deficit, preventing excessive humidification. Seasonal pattern (5) also has a high temperature and high saturated water vapor pressure, but because the actual humidity is low, a lower value is set to encourage humidification.

[0030] The control unit 12 determines a seasonal pattern using the data shown in Fig. 3(a) stored in the memory unit 10 based on the amount of solar radiation obtained from the solar radiation sensor 3 and the temperature obtained from the thermo-hygrometer 2. Furthermore, using the determined seasonal pattern, the current vapor deficit calculated by the vapor deficit calculation unit 11, the set vapor deficit set in the memory unit 10, and the data shown in Fig. 3(b) set in the memory unit 10, the control unit 12 calculates the deviation of the current vapor deficit from the set vapor deficit and a threshold value suited to the seasonal pattern. Furthermore, the control unit 12 compares the output value calculated by the PID calculation with this threshold value, and only when the output value exceeds the threshold value, outputs an ON signal to the relay 6, and operates the mist vent 7 via the relay 6 for a fixed ON time to humidify the air; otherwise, the mist vent 7 continues to be stopped for an additional period of time after the shortest OFF time immediately after control.

[0031] Next, the saturation deficit control in the low-pressure mist mode in the saturation deficit control device 1 described above will be described with reference to the flow chart of FIG. 4 and FIG. When control begins (S1), first, control is performed for the "shortest OFF time" to stop the mist 7. In other words, regardless of the conditions in the target space or the current operating status of the mist 7, the mist 7 is always stopped for the shortest ON time. The user can set the shortest ON time as desired using the setting unit 13, but in this embodiment it is set to, for example, 60 seconds.

[0032] Next, the "additional OFF time" is controlled to keep the mist 7 stopped. That is, the control unit 12 calculates the output value and the threshold value by PID calculation (S3). If the output value by the PID calculation is smaller than the threshold value (S4, YES), the control means C sends an OFF signal to the mist 7, which keeps the mist 7 OFF (S5). Furthermore, as long as it is within the control time (S6, YES), the above procedure is repeated, during which the mist 7 remains stopped. If it is not within the control time (S6, NO), the control ends (S7).

[0033] If the output value from the PID calculation is not smaller than the threshold value (S4, NO), the control means C sends an ON signal to the mist 7, which causes the mist 7 to operate for the fixed ON time and humidify. The fixed ON time can be set arbitrarily by the user using the setting unit 13, but in this embodiment it is set to 10 seconds, for example. If it is within the control time (S9, YES), the process returns to the control of the "shortest OFF time" (S2), and the above-described procedure is repeated. If it is not within the control time (S9, NO), the control ends (S7).

[0034] In the low-pressure mist mode, when control is initiated, the mist 7 is always stopped for the shortest OFF time. If the output value does not exceed the threshold, the stop time of the mist 7 is added, and the stopped state continues as long as the output value does not exceed the threshold. Even if the output value exceeds the threshold, the mist 7 only sprays for a set fixed ON time. In this way, in the low-pressure mist mode, the mist 7 is controlled to limit the spray time. Therefore, even if a low-pressure mist that sprays a drizzle-like mist with large droplets is used because low-pressure water from a water pipe or the like is used, the limited spray time reduces the risk of excessive wetting of crop leaves. This allows for both low equipment costs and proper crop growth through good saturation deficit control.

[0035] Next, the basic control mode will be described as another control mode that can be selected in saturation deficit control by this saturation deficit control device 1. The basic control mode is based on the premise of using high-pressure mist, which is generated by applying high pressure to water and spraying out fine mist particles. The low-pressure mist mode described above and the basic control mode described below can be switched between alternatively by the user's selection in the setting unit 13, and either one can be selected.

[0036] In basic control mode, PID calculations based on data from the memory unit 10 and environmental data from the sensor group S calculate an output value indicating the duration (operation time) of the mist 7 and a threshold value. If the output value exceeds the threshold, the mist 7 is operated for the shortest ON time. If the recalculated output value exceeds the threshold, the humidifier is controlled to operate for an additional humidification time according to the output value. However, repeated humidification time extensions can cause certain types of crops, such as spinach, to become overly wet, resulting in undesirable overhumidification. If such an event is anticipated, the setting unit 13 can be operated before control is initiated or upon encountering and determining such an event to issue a specific command to the control unit 12, thereby ending the additional humidification time extension and stopping the mist 7 for at least the shortest OFF time.

[0037] In the basic control mode, even if the current vapor pressure deficit is smaller than the set vapor pressure deficit or is only slightly larger, the humidifier operates for a specified period of time to avoid over-humidifying the target space, and the vapor pressure deficit of the target space can be controlled in a preferable manner suited to the season, allowing plants to properly photosynthesize in the target space. Furthermore, because the basic control mode is based on the use of high-pressure mist, the mist particles are small and therefore less likely to wet crops, making it relatively easy to manage crops and control humidity.

[0038] In the saturation deficit control in the low-pressure mist mode and basic control mode described above, if an abnormal value occurs in a control item, the alarm device 21 issues an alarm to alert the user. The types of alarms and their contents are as follows: The high temperature alarm is issued when the temperature measured by the thermo-hygrometer 2 is higher than the set value. The low temperature alarm is issued when the temperature measured by the thermo-hygrometer 2 is lower than the set value. The high humidity alarm is issued when the relative humidity measured by the thermo-hygrometer 2 is higher than the set value, or when the vapor deficit calculated by the vapor deficit calculation unit 11 is lower than the set value. The dryness alarm is triggered when the relative humidity is lower than the set value or the saturation deficit is higher than the set value. The high CO2 alarm is issued when the CO2 concentration measured by the CO2 monitor 4 is higher than a set value. The low CO2 alarm is issued when the CO2 concentration measured by the CO2 monitor 4 is lower than a set value. The sudden rise in saturation deficit alarm is triggered when the change in saturation deficit over a five-minute period is greater than the set value. The temperature sensor abnormality alarm and humidity sensor abnormality alarm are issued when the thermo-hygrometer 2 is abnormal. The solar radiation sensor abnormality alarm is issued when the solar radiation sensor 3 is abnormal. The CO2 sensor abnormality alarm is issued when the CO2 monitor 4 is abnormal. The excessive spray alarm is issued when the spray time is longer than the set value, and the saturation deficit control is forcibly stopped. In addition, these alarm output functions are provided with an alarm retention function, so that once an alarm is output, the alarm output continues even if the alarm disappears on the display screen of the setting unit 13, but this can be canceled by pressing the alarm reset button on the display screen of the setting unit 13.

[0039] Of the alarm outputs from the alarm device 21, the alarm for a sudden rise in saturation deficit is set based on knowledge of plant physiology. That is, according to this knowledge, in order to maintain the opening of the stomata in the leaves to promote the photosynthesis of crops, it is necessary that the saturation deficit does not change suddenly and that it is within an appropriate range (generally 3 to 6 g / L). 3 ) and once the saturation deficit has suddenly changed or deviated from the appropriate range, it is not easy to reopen the saturation deficit. Therefore, in this alarm device 21, the 5-minute saturation deficit change amount, which indicates the amount of change in saturation deficit in 5 minutes, is set to a predetermined reference value (for example, 5 gm 3) is exceeded, an alarm is issued. The reference value can be changed arbitrarily by the setting unit 13.

[0040] Furthermore, among the alarm outputs from the alarm device 21 described above, the excessive spray alarm can effectively deal with cases where the sensor group S has failed or where the mist 7 continues to be sprayed beyond the limit due to a programming error in the control means C.

[0041] Next, the CO2 control by the saturation deficit control device 1 of this embodiment will be described with reference to the flow chart of FIG. 5 and FIG. As shown in Fig. 5, when the control start time arrives at which crop photosynthesis begins and saturation deficit control in low-pressure mist mode is initiated, CO2 control also begins (S21). First, the control means C acquires solar radiation data from the solar radiation sensor 3, and the control unit 12 determines whether the measured solar radiation is greater than the control stop solar radiation, which is the lower limit for photosynthesis (S22). If the solar radiation is greater than the reference value (YES in S22), the control unit 12 determines whether the current vapor deficit calculated by the vapor deficit calculation unit 11 is within a range suitable for photosynthesis, i.e., between the lower limit and the upper limit (S23). If the current vapor deficit is between the lower limit and the upper limit (YES in S23), the control unit 12 acquires the CO2 concentration measurement result from the CO2 monitor 4 and determines whether the CO2 concentration is less than the lower limit (S24). If the CO2 concentration is below the lower limit (S24, YES), the sequencer 5 of the control means C outputs an ON / OFF signal to the relay 6, and the relay 6 operates the CO2 generator 8 intermittently according to the ON / OFF signal (S25). If the CO2 concentration acquired from the CO2 monitor 4 is not above the upper limit (S26, NO), the control unit 12 continues the intermittent operation of the CO2 generator 8 (S25). However, if the CO2 concentration is above the upper limit (S26, YES), and if it is within the control time (S27, YES), the control returns to S22 and continues to control the CO2 concentration. If it is not within the control time (S27, NO), the control of the CO2 concentration ends at the control end time when photosynthesis stops (S28).

[0042] If the measured amount of solar radiation is smaller than the reference value (S22, NO), if the current vapor deficit calculated by the vapor deficit calculation unit 11 is not within the range of the lower limit value or more and the upper limit value or less (S23, NO), or if the measured CO2 concentration is not equal to or less than the lower limit value (S24, NO), the control unit 12 will not perform intermittent operation of the CO2 generator 8 until the conditions for proper photosynthesis are satisfied, and will return to S22 to continue CO2 concentration control as long as it is within the control time (S29, YES), but if it is not within the control time (S29, NO), it will end CO2 concentration control at the control end time when photosynthesis will no longer be performed (S28).

[0043] The CO2 control by the saturation deficit control device 1 of this embodiment described above is performed in parallel with saturation deficit control in the low-pressure mist mode or basic control mode. This makes it possible to prevent the CO2 concentration from falling below the lower limit while the saturation deficit is being properly controlled, thereby achieving the effect of further promoting photosynthesis.

[0044] Furthermore, the saturation deficit control device 1 of this embodiment can be constructed by replacing only the control means with the control means C of this embodiment in an agricultural greenhouse already equipped with a sensor group S, such as a thermo-hygrometer 2, and a controlled device M, such as a mist vent 7. This allows for cost-effective retrofitting to existing equipment in the agricultural greenhouse. Furthermore, in such existing equipment, the minimum ON time for the mist vent 7 is set to, for example, 30 seconds. When control by the existing conventional control means begins and the output value is calculated, even if the calculated value is 1, spraying continues for 30 seconds. However, the saturation deficit control device 1 of this embodiment always stops the humidifier for the minimum OFF time after control begins, and continues to add control over the humidifier's stop time unless the calculated output value exceeds a threshold. Even if the output value exceeds the threshold, the humidifier is only operated for a relatively short fixed ON time. This prevents the humidifier from being controlled to limit the spray time, preventing the saturation deficit from becoming too small.

[0045] When a low-cost, low-pressure humidifier that uses low-pressure water from a water pipe or the like is used as a humidifier for saturation deficit control in an agricultural greenhouse, the mist that is sprayed is drizzle-like and has large particle sizes, so that the crops tend to get wet easily. However, with this saturation deficit control device, it is possible to appropriately limit the spray time, so that saturation deficit control in the target space can be performed appropriately even when such a low-cost humidifier is used. [Explanation of symbols]

[0046] 1...Saturation deficit control device 7...Humidifier (mist) 8...CO2 generator 10...Storage section 11...Saturation difference calculation section 12...Control unit S: Sensor group M: Controlled equipment C...Control means

Claims

1. A saturation deficit control device that controls the operation of a humidifier so that the current saturation deficit of a target space becomes a set saturation deficit, When the control is started, the humidifier is first stopped for the shortest OFF time, Thereafter, an output value indicating the stop time of the humidifier is calculated, and if the output value does not exceed a threshold value, the procedure of adding an OFF time to continue the stop of the humidifier is repeated as long as it is within the control time; A saturation deficit control device characterized by having a control means for operating the humidifier for a fixed ON time only when the output value exceeds the threshold value, and for stopping the humidifier for the shortest OFF time if it is within the control time, and then repeating the procedure of the added OFF time.

2. The control means a storage unit that stores the set vapor pressure deficit and a plurality of seasonal patterns; a vapor pressure deficit calculation unit that calculates the current vapor pressure deficit using the temperature and humidity of the target space; a control unit that calculates the threshold value based on the temperature and solar radiation of the target space, the deviation between the current vapor pressure deficit and the set vapor pressure deficit, and the seasonal pattern; 2. The saturation deficit control device according to claim 1, further comprising:

3. A saturation deficit control device that operates a CO 2 generator so that the CO 2 concentration measured by a CO 2 monitor does not fall below a lower limit value, When the control is started, the control means When the amount of solar radiation is greater than the control stop solar radiation amount, the current vapor pressure deficit is equal to or greater than the lower limit value and equal to or less than the upper limit value, and the CO 2 concentration is equal to or less than the lower limit value, an operation control is performed to operate the CO 2 generating device; 3. The saturation deficit control device according to claim 2, wherein the operation of the CO2 generating device is continued when the CO2 concentration is not equal to or greater than the upper limit value, but the operation control is continued within a control time when the CO2 concentration is equal to or greater than the upper limit value.

4. A saturation deficit control device described in any one of claims 1 to 3, characterized in that the humidifier is a low-pressure humidifier that sprays a drizzle-like mist using low-pressure water such as water from a water pipe.

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