Air Conditioning System

Abstract

To provide an air conditioning system capable of stably controlling the dew point in a low dew point room even when only fresh outside air is passed through a dehumidification rotor. An air conditioning system 1 calculates a set dew point temperature SP for a first dew point temperature 11 indicating the dew point temperature of dehumidified air based on a change in at least a second dew point temperature 22 indicating the dew point temperature inside a room. Then, the air conditioning system 1 executes at least one of control of the rotation speed of a dehumidification rotor 101, temperature adjustment control of a regenerative heater 121, and air volume adjustment control of fans (a first fan 112, a second fan 124) so ​​that the first dew point temperature 11 follows the set dew point temperature SP.

Description

[Technical field]

[0001] The present disclosure relates to an air conditioning system that supplies low dew point air to a room. [Background technology]

[0002] Patent Document 1 discloses a dew point adjustment method that uses a dry dehumidifier (dehumidification rotor) to adjust the dew point of drying air supplied to a drying device. The dew point adjustment method uses a dehumidification rotor to adjust the dew point of circulating air from the drying device to be lower than the steady supply dew point, and supplies drying air to the drying device after the outlet dew point of the dehumidification rotor is humidified by a downstream air supply side humidifier to be adjusted to the steady supply dew point. The dew point adjustment method uses a regeneration air heater (regeneration heater) to increase the temperature of regeneration air passed through the dehumidification rotor within a certain time period when the drying state becomes steady. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 04-061908 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is an increasing demand for only fresh outdoor air to pass through the dehumidification rotor, rather than a mixture of outdoor air and return air. In this case, the dew point adjustment method shown in Patent Document 1 does not take into account the dew point in the low dew point room, so there is a risk that the dew point will fluctuate drastically due to latent heat generation in the low dew point room.

[0005] One object of the present disclosure is to provide an air conditioning system that can stably control the dew point in a low dew point room even when only fresh outside air is passed through the dehumidification rotor. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to an air conditioning system that supplies air with a low dew point to a room. The air conditioning system includes a dehumidification rotor having a first area provided in a first duct connected to the room and absorbing moisture contained in the outside air and discharging the dehumidified air to the first duct, and a second area provided in a second duct connected to an exhaust port and discharging humid air containing the absorbed moisture to the second duct, a regenerative heater provided in the second duct on the inlet side of the second area for heating the humid air, and a regenerative heater provided in the second duct on the outlet side of the second area for heating the humid air. Re The device is equipped with a fan that sends out the hot and humid air heated by the regenerative heater toward the exhaust port, and a controller that is connected to the dehumidification rotor, the regenerative heater, and the fan. , room Based on the change in the second dew point temperature, which indicates the dew point temperature within , or based on a change in the deviation between the second dew point temperature and the indoor target dew point temperature, The set dew point temperature for the first dew point temperature, which indicates the dew point temperature of the dehumidified air, is Gradual change Then, the controller executes at least one of control of the rotation speed of the dehumidification rotor, control of temperature regulation of the regenerative heater, and control of air volume regulation of the fan so that the first dew point temperature follows the set dew point temperature. Effect of the Invention

[0007] According to the present disclosure , room Based on the change in the second dew point temperature, which indicates the dew point temperature within , or based on a change in the deviation between the second dew point temperature and the indoor target dew point temperature, The set dew point temperature for the first dew point temperature, which indicates the dew point temperature of the dehumidified air, is Gradual change At least one of the following controls is executed to make the first dew point temperature follow the set dew point temperature: control of the rotation speed of the dehumidification rotor, temperature adjustment control of the regenerative heater, and air volume adjustment control of the fan. By reflecting the second dew point temperature in the control, the second dew point temperature can be made to follow the first dew point temperature even when only fresh outside air is passed through the dehumidification rotor. Therefore, the dew point in the low dew point room can be stably controlled. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration example of an air conditioning system according to an embodiment; [Diagram 2]2 is a block diagram showing an example of a functional configuration of a controller according to the embodiment; FIG. [Diagram 3] 6A and 6B are diagrams for explaining a setting example of a set dew-point temperature according to the embodiment. [Figure 4] 6 is a diagram for explaining an example of change in the set dew-point temperature according to the embodiment. FIG. [Diagram 5] 5 is a flowchart showing an example of a process of a controller for changing a set dew-point temperature according to the embodiment. [Figure 6] 5 is a flowchart showing an example of a process of a controller for changing a set dew-point temperature according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An air conditioning system according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Elements common to the various drawings will be designated by the same reference numerals and duplicated descriptions will be omitted.

[0010] 1. Example of air conditioning system configuration 1 is a block diagram showing a configuration example of an air conditioning system 1. The air conditioning system 1 supplies low dew point air to a low dew point room 20. The low dew point room 20 is managed, for example, within a dew point temperature range of -50°C DP to -40°C DP. Examples of the low dew point room 20 include a dry room, a clean room, and the like.

[0011] The air conditioning system 1 includes a low dew point room 20, a dry dehumidifier 100, and a controller 30. The dry dehumidifier 100 generates air to be supplied to the low dew point room 20 (also simply referred to as the room). The dry dehumidifier 100 includes a first duct 131, a second duct 132, a dehumidification rotor 101, a first fan 112, a second fan 124, a regenerative heater 121, a precooler 111, an aftercooler 114, and an afterheater 115.

[0012] One end of the first duct 131 is connected to an outside air port, and the other end is connected to the low dew point chamber 20. One end of the second duct 132 is connected to an outside air port, and the other end is connected to an exhaust port. The outside air port connected to the first duct 131 and the outside air port connected to the second duct 132 may be the same or different.

[0013] The dehumidifying rotor 101 has a rotating mechanism that rotates in one direction and rotates at an arbitrary rotation speed. The dehumidifying rotor 101 is equipped with a power conversion device 102 (also simply referred to as an inverter 102) for driving and controlling the rotating mechanism. The rotating mechanism is driven and controlled based on a command from the inverter 102. The inverter 102 is controlled by a controller 30, which will be described later.

[0014] The dehumidification rotor 101 has a first area and a second area. The first area has a function of absorbing moisture contained in the outside air sucked from the outside air port through the first filter 110 and discharging the dehumidified air. The second area has a function of discharging humid air containing the absorbed moisture and the outside air sucked from the outside air port through the second filter 120. The humid air may contain the outside air sucked into the first duct 131. For example, when the first branch duct 131A is provided between the inlet side of the first area in the first duct 131 and the inlet side of the second area in the second duct 132, the outside air sucked into the first duct 131 is supplied to the second duct 132 through the first branch duct 131A.

[0015] The first fan 112 is provided on the inlet side of the first area of ​​the dehumidification rotor 101 in the first duct 131, and draws in outside air from an outside air port and sends it out toward the inlet side of the first area, and also sends the outside air out toward the second duct 132 via the first branch duct 131A. The first fan 112 includes a power conversion device 113 (also simply referred to as an inverter 113) for driving the fan. The inverter 113 is controlled by a controller 30, which will be described later.

[0016] The second fan 124 is provided on the outlet side of the second area of ​​the dehumidification rotor 101 in the second duct 132, and draws in outside air from the outside air port and sends it out toward the inlet side of the second area, and also sends out high-temperature, humid air that is exhausted from the outlet side of the second area and heated by the regenerative heater 121 toward the exhaust port. The second fan 124 includes a power conversion device 125 (also simply referred to as inverter 125) for driving the fan. The inverter 125 is controlled by a controller 30, which will be described later.

[0017] The regenerative heater 121 is provided on the inlet side of the second area of ​​the dehumidification rotor 101 in the second duct 132, and heats the humid air. The regenerative heater 121 includes a thyristor 122 that adjusts the power of the heater. The thyristor 122 is controlled by a controller 30, which will be described later. The temperature of the humid air heated by the regenerative heater 121 is monitored by the controller 30, which will be described later. The temperature of the humid air is measured by a thermometer 123 (also referred to as a thermometer T) provided on the inlet side of the second area of ​​the dehumidification rotor 101 in the second duct 132.

[0018] The precooler 111 is provided in the first duct 131 between the first filter 110 and the first fan 112, and cools the outside air taken in from the outside air port. In this case, the precooler 111 may be supplied with cold water for cooling the outside air.

[0019] The aftercooler 114 cools the dehumidified air discharged from the dehumidification rotor 101. This makes it possible to suppress an increase in the temperature of the dehumidified air. In this case, the aftercooler 114 may be supplied with cold water for cooling the dehumidified air.

[0020] The after-heater 115 heats the dehumidified air cooled by the after-cooler 114. This can further improve the drying effect of the dehumidified air.

[0021] The controller 30 controls the dry dehumidifier 100 so as to supply low dew point air to the low dew point chamber 20. Specifically, the controller 30 executes drive control of the dehumidification rotor 101, the regenerative heater 121, the first fan 112, and the second fan 124 based on a second dew point temperature 22 (also referred to as the second dew point temperature DP2) indicating the dew point temperature of the low dew point chamber 20 (room) and a first dew point temperature 11 (also referred to as the first dew point temperature DP1) indicating the dew point temperature of the dehumidified air. Details of the various controls executed by the controller 30 will be described later.

[0022] 2. Controller function configuration example 2 is a block diagram showing an example of the functional configuration of the controller 30. The controller 30 includes a supply air dew point temperature setting control unit 200 and an equipment drive control unit 210. The supply air dew point temperature setting control unit 200 calculates a set supply air dew point temperature SP (hereinafter simply referred to as set dew point temperature SP) for the first dew point temperature 11 based on at least a change in the second dew point temperature 22.

[0023] Specifically, the supply air dew point temperature setting control unit 200 includes a set supply air dew point temperature state determination unit 201 and a set supply air dew point temperature setting unit 202. The set supply air dew point temperature state determination unit 201 determines the state of the set dew point temperature SP based on the state of the second dew point temperature 22. The state of the set dew point temperature SP is expressed, for example, as OFF, ON1, ON2, and ON3. The state of the set dew point temperature SP will be described in detail later.

[0024] The set supply air dew point temperature setting unit 202 sets the set dew point temperature SP for the first dew point temperature 11 based on the state of the set dew point temperature SP determined by the set supply air dew point temperature state determination unit 201. The setting of the set dew point temperature SP is expressed, for example, as a reference value of the set dew point temperature SP (hereinafter referred to as reference SP), reference SP+2°CDP, reference SP+4°CDP, or reference SP+6°CDP. The setting of the set dew point temperature SP will be described later in detail.

[0025] In this way, the supply air dew point temperature setting control unit 200 changes the set dew point temperature SP based on a change in the second dew point temperature 22. As another example, the supply air dew point temperature setting control unit 200 may change the set dew point temperature SP based on a change in the deviation between the second dew point temperature 22 and the indoor target dew point temperature (hereinafter referred to as the target indoor dew point temperature). The change in the set dew point temperature SP will be described later in detail.

[0026] The equipment drive control unit 210 executes at least one of the following controls: rotation speed control of the dehumidification rotor 101, temperature adjustment control of the regeneration heater 121, air volume adjustment control of the first fan 112, and air volume adjustment control of the second fan 124, so as to cause the first dew point temperature 11 to follow the set dew point temperature SP.

[0027] For example, when the first dew-point temperature 11 is higher than the set dew-point temperature SP, the device drive control unit 210 executes at least one of increasing the rotation speed of the dehumidification rotor 101, increasing the set temperature of the regenerative heater 121, and increasing the air volume of the fans (first fan 112, second fan 124) so ​​as to increase the adsorption capacity of the dehumidification rotor 101. The set temperature of the regenerative heater 121 may be determined based on temperature information of the humid air measured by the thermometer 123.

[0028] As another example, when the first dew point temperature 11 is lower than the set dew point temperature SP, the equipment drive control unit 210 performs at least one of the following to reduce the rotation speed of the dehumidification rotor 101 so as to reduce the adsorption capacity of the dehumidification rotor 101: to lower the set temperature of the regeneration heater 121; and to reduce the airflow of the fans (first fan 112, second fan 124).

[0029] Furthermore, in controlling the rotation speed of the dehumidification rotor 101, the device drive control unit 210 generates and outputs a drive control signal (e.g., PWM signal) for the inverter 102. In controlling the temperature adjustment of the regenerative heater 121, the device drive control unit 210 generates and outputs a drive control signal for the thyristor 122. In controlling the air volume adjustment of the fans (first fan 112, second fan 124), the device drive control unit 210 generates and outputs a drive control signal (e.g., PWM signal) for the inverters (inverter 113, inverter 125).

[0030] In this way, by executing various controls by the controller 30, the first dew point temperature 11 can be made to follow the set dew point temperature SP. This allows the second dew point temperature 22 to follow the first dew point temperature 11, and the dew point in the low dew point chamber 20 can be stably controlled.

[0031] 3. Setting dew point temperature SP 3-1. Overview Consider a case where only outdoor air is passed through the dehumidification rotor 101. The outdoor dew point temperature varies depending on the weather and season. For example, the outdoor dew point temperature rises in rainy weather, but falls in the dry winter season. The controller 30 executes control to make the first dew point temperature 11 follow the set dew point temperature SP in order to bring the second dew point temperature 22 closer to the target indoor dew point temperature. However, when the outdoor dew point temperature rises, such as in rainy weather, there is a possibility that the first dew point temperature 11 cannot be stably made to follow the set dew point temperature SP due to the influence of disturbances (outdoor dew point temperature). In this case, there is a risk that the control performance of the air conditioning system 1 will deteriorate.

[0032] According to this embodiment, even when affected by disturbance (outside air dew-point temperature), the set dew-point temperature SP is changed so that the first dew-point temperature 11 stably follows the set dew-point temperature SP.

[0033] 3-2.Settings example 3 is a diagram for explaining a setting example of the set dew-point temperature SP according to the embodiment. As described above, the second dew-point temperature 22 changes based on the first dew-point temperature 11 supplied to the low dew-point chamber 20. The first dew-point temperature 11 is controlled to follow the set dew-point temperature SP. In other words, it can be said that the second dew-point temperature 22 changes based on the set dew-point temperature SP. Based on this, a setting example of the set dew-point temperature SP will be described in detail.

[0034] First, consider the case where the second dew point temperature 22 drops. There are three cases in which the second dew point temperature 22 drops, as shown in FIG. 3. Specifically, in case 1, the second dew point temperature 22 drops below the second threshold (e.g., −44° C. DP). In this case, the set supply air dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from OFF to ON1. In case 2, the second dew point temperature 22 drops below the third threshold (e.g., −46° C. DP). In this case, the set supply air dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from ON1 to ON2. In case 3, the second dew point temperature 22 drops below the fourth threshold (e.g., −48° C. DP). In this case, the set supply air dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from ON2 to ON3.

[0035] Next, consider a case where the second dew point temperature 22 rises. It is required that the second dew point temperature 22 be controlled so as not to exceed the upper limit value of the low dew point chamber 20. The upper limit value of the low dew point chamber 20 is, for example, -40°C DP. There are three cases in which the second dew point temperature 22 rises, as shown in FIG. 3. Specifically, in case 1, the second dew point temperature 22 rises to a first threshold value (e.g., -42°C DP) or higher. In this case, the set supply air dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from ON1 to OFF. In case 2, the second dew point temperature 22 rises to a second threshold value (e.g., -44°C DP) or higher. In this case, the set supply air dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from ON2 to ON1. In case 3, the second dew point temperature 22 rises to a third threshold value (e.g., -46°C DP) or higher. In this case, the set supply air dew-point temperature state determination unit 201 switches the state of the set dew-point temperature SP from ON3 to ON2.

[0036] The set supply air dew point temperature setting unit 202 determines the set dew point temperature SP based on the state of the set dew point temperature SP. Specifically, when the state of the set dew point temperature SP is "OFF", the set supply air dew point temperature setting unit 202 sets the set dew point temperature SP as the reference SP. The reference SP is, for example, -50°C DP. When the state of the set dew point temperature SP is "ON1", the set supply air dew point temperature setting unit 202 sets the set dew point temperature SP as the reference SP + 2°C DP (e.g., -48°C DP). When the state of the set dew point temperature SP is "ON2", the set supply air dew point temperature setting unit 202 sets the set dew point temperature SP as the reference SP + 4°C DP (e.g., -46°C DP). When the state of the set dew point temperature SP is "ON3", the set supply air dew point temperature setting unit 202 sets the set dew point temperature SP as the reference SP + 6°C DP (e.g., -44°C DP). 3, the set supply air dew point temperature setting unit 202 sets the set dew point temperature SP in increments of 2° C. DP, but this is not limited to this. For example, the set supply air dew point temperature setting unit 202 may set the set dew point temperature SP in increments of 1° C. DP, or may set the set dew point temperature SP in increments of values ​​greater than 2° C. DP.

[0037] By setting the set dew point temperature SP in stages in this manner, the set dew point temperature SP having a dead zone is set as shown in Fig. 3. This allows the set dew point temperature SP to be set in stages, and the first dew point temperature 11 to stably follow the set dew point temperature SP even if the second dew point temperature 22 changes suddenly. Therefore, the dew point in the low dew point chamber 20 can be stably controlled.

[0038] 3-3. Examples of changes 3-3-1. First example FIG. 4 is a diagram for explaining an example of change in the set dew-point temperature SP according to the embodiment. First, consider a case where the second dew-point temperature 22 drops. In this case, it is assumed that the set dew-point temperature SP is lower than the second dew-point temperature 22. In the example shown in FIG. 4, when the second dew-point temperature 22 drops, the second dew-point temperature 22 is near the target indoor dew-point temperature (e.g., -42°C DP), and the state of the set dew-point temperature SP is "OFF". Therefore, the controller 30 sets the set dew-point temperature SP as the reference SP (e.g., -50°C DP).

[0039] When the state of the set dew-point temperature SP is "OFF" and the second dew-point temperature 22 is less than the second threshold value (e.g., -44°C DP), that is, when the second dew-point temperature 22 drops by 2°C DP from the target indoor dew-point temperature, the controller 30 determines the state of the set dew-point temperature SP to be "ON1". After that, the controller 30 sets the set dew-point temperature SP as SP+2°C DP (e.g., -48°C DP). That is, the controller 30 raises the set dew-point temperature SP by 2°C DP to suppress the drop of the second dew-point temperature 22. As the set dew-point temperature SP rises by 2°C DP, the first dew-point temperature 11 rises by 2°C DP to follow the set dew-point temperature SP. This reduces the gradient of the second dew-point temperature 22, and the drop of the second dew-point temperature 22 can be suppressed.

[0040] When the state of the set dew-point temperature SP is "ON1" and the second dew-point temperature 22 is less than the third threshold value (e.g., -46°C DP), that is, when the second dew-point temperature 22 drops by 4°C DP from the target indoor dew-point temperature, the controller 30 determines the state of the set dew-point temperature SP to be "ON2". After that, the controller 30 sets the set dew-point temperature SP as SP+4°C DP (-46°C DP). That is, the controller 30 further increases the set dew-point temperature SP by 2°C DP to suppress the drop of the second dew-point temperature 22. As the set dew-point temperature SP increases by 2°C DP, the first dew-point temperature 11 increases by 2°C DP to follow the set dew-point temperature SP. This further reduces the gradient of the second dew-point temperature 22, and the drop of the second dew-point temperature 22 can be further suppressed.

[0041] When the state of the set dew-point temperature SP is "ON2", if the second dew-point temperature 22 stably follows the first dew-point temperature 11, it can be said that the second dew-point temperature 22 is stable. In this case, the controller 30 maintains the set dew-point temperature SP at SP+4°CDP (e.g., -46°CDP).

[0042] Next, consider the case where the second dew-point temperature 22 rises. For example, as shown in FIG. 4, when the state of the set dew-point temperature SP is "ON2", if the second dew-point temperature 22 is equal to or higher than the second threshold (e.g., -44°C DP), that is, if the deviation between the second dew-point temperature 22 and the set dew-point temperature SP is equal to or higher than 2°C DP, the controller 30 determines the state of the set dew-point temperature SP to be "ON1". After that, the controller 30 sets the set dew-point temperature SP as SP+2°C DP (e.g., -48°C DP). That is, the controller 30 lowers the set dew-point temperature SP by the deviation, 2°C DP, so that the second dew-point temperature 22 does not exceed the upper limit value of the low dew-point chamber 20. As the set dew-point temperature SP drops by 2°C DP, the first dew-point temperature 11 drops by 2°C DP to follow the set dew-point temperature SP. This causes the second dew point temperature 22 to change from rising to falling, and prevents the second dew point temperature 22 from exceeding the upper limit of the low dew point chamber 20. Furthermore, by preventing the second dew point temperature 22 from exceeding the upper limit of the low dew point chamber 20, the load on the battery (such as a battery) provided in the controller 30 can be reduced, allowing the air conditioning system 1 to operate efficiently.

[0043] 4, the state of the set dew-point temperature SP changes in the order of OFF, ON1, ON2, and ON1, and the set dew-point temperature SP changes in the order of reference SP (e.g., -50°C DP), reference SP+2°C DP (e.g., -48°C DP), reference SP+4°C DP (e.g., -46°C DP), and reference SP+4°C DP (e.g., -48°C DP). The gradual changes in the set dew-point temperature SP vary and include at least one of a decrease in the set dew-point temperature SP and an increase in the set dew-point temperature SP.

[0044] Thus, according to the first example, the controller 30 (supply air dew point temperature setting control section 200) changes the set dew point temperature SP in a stepwise manner based on a change in the second dew point temperature 22. Alternatively, the controller 30 (supply air dew point temperature setting control section 200) changes the set dew point temperature SP in a stepwise manner based on a change in the deviation between the second dew point temperature 22 and the target indoor dew point temperature. This allows the controller 30 to control the second dew point temperature 22 so that it approaches the target indoor dew point temperature within a range not exceeding the upper limit value (-40°C DP) of the low dew point chamber 20. Therefore, even when only fresh outdoor air is passed through the dehumidification rotor 101, the dew point in the low dew point chamber 20 can be stably controlled.

[0045] 3-3-2. Second example Consider a case where the set dew point temperature SP is changed in a stepwise manner. In this case, the second dew point temperature 22 may repeatedly drop and rise, and the second dew point temperature 22 may become unstable. This phenomenon is also called hunting. In particular, when the set dew point temperature SP is changed while the second dew point temperature 22 is dropping, hunting may occur if the second dew point temperature 22 becomes lower than the first dew point temperature 11. In order to prevent hunting of the second dew point temperature 22, it is preferable to control the timing of the stepwise change of the set dew point temperature SP so that the second dew point temperature 22 does not become lower than the first dew point temperature 11.

[0046] According to the second example, the controller 30 controls the timing of gradually changing the set dew-point temperature SP according to the first example described above. Specifically, as shown in FIG. 4, when the state of the set dew-point temperature SP is "OFF" and the second dew-point temperature 22 is less than the second threshold (e.g., -44°C DP), that is, when the second dew-point temperature 22 drops by 2°C DP from the target indoor dew-point temperature, the controller 30 raises the set dew-point temperature SP by 2°C DP after a predetermined time has elapsed. That is, the controller 30 (the set supply air dew-point temperature state determination unit 201) delays the timing of raising the set dew-point temperature SP by 2°C DP, that is, the timing of switching the state of the set dew-point temperature SP from "OFF" to "ON1". The predetermined time is, for example, a time determined in advance. Also, the predetermined time is, for example, set by a timer provided in the controller 30.

[0047] 4, when the state of the set dew-point temperature SP is "ON1" and the second dew-point temperature 22 is less than the third threshold value (e.g., -46°C DP), i.e., when the second dew-point temperature 22 drops by 4°C DP from the target indoor dew-point temperature, the controller 30 further increases the set dew-point temperature SP by 2°C DP after a predetermined time has elapsed. In other words, the controller 30 (set supply air dew-point temperature state determination unit 201) delays the timing of further increasing the set dew-point temperature SP by 2°C DP, i.e., the timing of switching the state of the set dew-point temperature SP from "ON1" to "ON2."

[0048] In this manner, the controller 30 When the second dew point temperature 22 is decreasing, The set dew point temperature SP is maintained until a predetermined time has elapsed. After the predetermined time has elapsed, the controller 30 increases the set dew point temperature SP. This makes it possible to prevent the second dew point temperature 22 from becoming lower than the first dew point temperature 11, and to prevent hunting of the second dew point temperature 22. Therefore, compared to the effect of the first example described above, it is expected that the dew point in the low dew point chamber 20 can be controlled more stably.

[0049] In addition, when the second dew point temperature 22 rises, as described above, it is necessary that the second dew point temperature 22 does not exceed the upper limit value of the low dew point chamber 20 (e.g., -40°C DP). When the temperature difference between the second dew point temperature 22 and the set dew point temperature SP is equal to or greater than a predetermined temperature (e.g., equal to or greater than 2°C DP), it is preferable to immediately lower the set dew point temperature SP by 2°C DP. Therefore, when the temperature difference between the second dew point temperature 22 and the set dew point temperature SP is equal to or greater than a predetermined temperature as the second dew point temperature 22 rises, the controller 30 lowers the set dew point temperature SP. This makes it possible to prevent the second dew point temperature 22 from exceeding the upper limit value of the low dew point chamber 20.

[0050] The control system in the controller 30 in the first and second examples may be a cascade control system in which a control loop (also called a major loop) that makes the second dew point temperature 22 follow the target indoor dew point temperature is provided inside a control loop (also called a minor loop) that makes the first dew point temperature 11 gradually follow the set dew point temperature SP in response to changes in the set dew point temperature SP.

[0051] 3-4. Processing example Figures 5 and 6 are flow charts showing an example of processing by the controller 30 for changing the set dew-point temperature SP according to the embodiment. Figures 5 and 6 show an example of processing in which the second dew-point temperature 22, which is near the target indoor dew-point temperature (-42°C DP), drops and the set dew-point temperature SP is changed to raise the second dew-point temperature 22 to the target indoor dew-point temperature. The reference SP is -50°C DP.

[0052] In step S100, the air conditioning system 1 (controller 30) determines whether the second dew-point temperature 22 (second dew-point temperature DP2) has fallen below a second threshold (e.g., −44° C. DP). If it is determined that the second dew-point temperature DP2 has fallen below the second threshold (step S100; Yes), the process proceeds to step S110. Otherwise (step S100; No), the process proceeds to step S150.

[0053] In step S110, the controller 30 starts a timer to wait until a predetermined time has elapsed. After the predetermined time has elapsed, the process proceeds to step S120.

[0054] In step S120, the controller 30 increases the set dew-point temperature SP by 2° C. DP. That is, the controller 30 switches the state of the set dew-point temperature SP from OFF to ON1, and sets the set dew-point temperature SP as the reference SP+2° C. DP (−48° C. DP). After that, the process proceeds to step S130.

[0055] In step S130, the controller 30 determines whether the second dew-point temperature DP2 has fallen below the third threshold (e.g., −46° C. DP). If it is determined that the second dew-point temperature DP2 has fallen below the third threshold (step S130; Yes), the process proceeds to step S140. Otherwise (step S130; No), the process proceeds to step S160.

[0056] In step S140, the controller 30 starts a timer to wait until a predetermined time has elapsed. After the predetermined time has elapsed, the process proceeds to step S200.

[0057] In step S150, the controller 30 maintains the state of the set dew-point temperature SP in OFF. If the state of the set dew-point temperature SP is not OFF, the controller 30 switches the state of the set dew-point temperature SP to OFF and sets the set dew-point temperature SP as the reference SP-0°C DP (-50°C DP). Then, the process ends.

[0058] The case where the state of the set dew-point temperature SP is not OFF is, for example, the case where the state of the set dew-point temperature SP is ON1 and step S160 described later is "Yes". In this case, the controller 30 switches the state of the set dew-point temperature SP to OFF and sets the set dew-point temperature SP as the reference SP-0°CDP (-50°CDP) so that the second dew-point temperature DP2 does not rise and exceed the upper limit value of the low dew-point chamber 20. This makes it possible to prevent the second dew-point temperature DP2 from exceeding the upper limit value of the low dew-point chamber 20.

[0059] In step S160, the controller 30 determines whether the second dew-point temperature DP2 has risen to or above the first threshold (e.g., −42° C. DP). If it is determined that the second dew-point temperature DP2 has risen to or above the first threshold (step S160; Yes), the process proceeds to step S150. Otherwise (step S160; No), the process returns to step S130.

[0060] In step S200, the controller 30 further increases the set dew-point temperature SP by 2° C. DP. That is, the controller 30 switches the state of the set dew-point temperature SP from ON1 to ON2, and sets the set dew-point temperature SP to the reference SP+4° C. DP (−46° C. DP). Then, the process proceeds to step S210.

[0061] In step S210, the controller 30 determines whether the second dew-point temperature DP2 has risen to or above the second threshold (e.g., −44° C. DP). If it is determined that the second dew-point temperature DP2 has risen to or above the second threshold (step S210; Yes), the process proceeds to step S120. Otherwise (step S210; No), the process proceeds to step S220.

[0062] In step S220, the controller 30 determines whether the second dew-point temperature DP2 has fallen below the fourth threshold (e.g., −48° C. DP). If it is determined that the second dew-point temperature DP2 has fallen below the fourth threshold (step S220; Yes), the process proceeds to step S230. Otherwise (step S220; No), the process returns to step S210.

[0063] In step S230, the controller 30 starts a timer to wait until a predetermined time has elapsed. After the predetermined time has elapsed, the process proceeds to step S240.

[0064] In step S240, the controller 30 further increases the set dew-point temperature SP by 2° C. DP. That is, the controller 30 switches the state of the set dew-point temperature SP from ON2 to ON3, and sets the set dew-point temperature SP to the reference SP + 6° C. DP (−44° C. DP). Then, the process ends. This makes it possible to bring the second dew-point temperature DP2 closer to the target indoor dew-point temperature (e.g., −42° C. DP).

[0065] 3-5.Modifications The above-mentioned set dew-point temperature SP has a dead zone, but is not limited to this. For example, the set dew-point temperature SP may be set without a dead zone. For example, the set dew-point temperature SP may be set linearly (straight line, curved line). In this case, it is desirable that the first dew-point temperature 11 can stably follow the set dew-point temperature SP even if the second dew-point temperature 22 changes suddenly.

[0066] According to the modified example of the embodiment, when there is no dead zone in the set dew point temperature SP, the controller 30 uses a timer to control the timing of changing the set dew point temperature SP. This allows the first dew point temperature 11 to stably follow the set dew point temperature SP even if the second dew point temperature 22 changes suddenly. Therefore, the dew point in the low dew point chamber 20 can be stably controlled. [Explanation of symbols]

[0067] 1...air conditioning system, 11...first dew point temperature, 20...low dew point room, 22...second dew point temperature, 30...controller, 100...dry dehumidifier, 101...dehumidification rotor, 102...inverter, 110...first filter, 111...precooler, 112...first fan, 113...inverter, 114...aftercooler, 115...afterheater, 120...second filter, 121...regenerative heater, 122...thyristor, 123...thermometer, 124...second fan, 125...inverter, 131...first duct, 131A...first branch duct, 132...second duct, 200...supply air dew point temperature setting control unit, 201...set supply air dew point temperature state determination unit, 202...set supply air dew point temperature setting unit, 210...equipment drive control unit

Claims

1. An air conditioning system that supplies low dew point air to a room, a dehumidification rotor having a first area provided in a first duct connected to the indoor space and absorbing moisture contained in the outside air and discharging the dehumidified air to the first duct, and a second area provided in a second duct connected to an exhaust port and discharging humid air containing the absorbed moisture to the second duct; a regenerative heater provided on an inlet side of the second area in the second duct and configured to heat the humid air; a fan provided on an outlet side of the second area in the second duct, the fan sending out the high-temperature, high-humidity air obtained by heating the humid air by the regenerative heater toward the exhaust port; a controller connected to each of the dehumidification rotor, the regenerative heater, and the fan; The controller: changing a set dew-point temperature relative to a first dew-point temperature indicating a dew-point temperature of the dehumidified air in a stepwise manner based on a change in a second dew-point temperature indicating a dew-point temperature in the room or based on a change in a deviation between the second dew-point temperature and a target dew-point temperature in the room; and executing at least one of control of the rotation speed of the dehumidification rotor, control of temperature regulation of the regenerative heater, and control of air volume regulation of the fan so that the first dew point temperature follows the set dew point temperature. An air conditioning system characterized by:

2. An air conditioning system as claimed in claim 1, The controller, in the process of gradually changing the set dew point temperature, A process of determining whether to lower or raise the state of the set dew point temperature based on a change in the second dew point temperature or a change in the deviation between the second dew point temperature and a target dew point temperature in the room; and a process of setting the set dew point temperature so as to decrease or increase the set dew point temperature based on the determined state of the set dew point temperature. An air conditioning system characterized by:

3. 3. The air conditioning system according to claim 2, the step change includes an increase in the set dew point temperature; In the process of setting the set dew point temperature, the controller If the second dew point temperature is decreasing, the set dew point temperature is set to be maintained until a predetermined time has elapsed; and after the predetermined time has elapsed, the set dew point temperature is set to be increased based on the determined state of the set dew point temperature. An air conditioning system characterized by:

4. 3. The air conditioning system according to claim 2, the step change includes a decrease in the set dew point temperature; In the process of setting the set dew point temperature, the controller If the second dew point temperature is increasing, the set dew point temperature is set to be decreased based on the determined state of the set dew point temperature. An air conditioning system characterized by:

5. 2. The air conditioning system according to claim 1, The controller: When the first dew point temperature is higher than the set dew point temperature, at least one of increasing the rotation speed of the dehumidification rotor, increasing the set temperature of the regeneration heater, and increasing the air volume of the fan is executed so as to increase the adsorption capacity of the dehumidification rotor; When the first dew point temperature is lower than the set dew point temperature, at least one of the following is executed to reduce the rotation speed of the dehumidification rotor, to reduce the set temperature of the regenerative heater, and to reduce the air volume of the fan so as to reduce the adsorption capacity of the dehumidification rotor. An air conditioning system characterized by:

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