Air conditioning system

Abstract

This air conditioning system provides stable control of the dew point in a low-dew-point room, even when only fresh outside air is passed through the dehumidifying rotor. [Solution] The air conditioning system 1 calculates a set dew point temperature SP for the first dew point temperature 11, which indicates the dew point temperature of the dehumidified air, based on the change in the second dew point temperature 22, which indicates the dew point temperature of the room. Then, in order to make the first dew point temperature 11 follow the set dew point temperature SP, the air conditioning system 1 performs at least one of the following controls: rotation speed control of the dehumidifying rotor 101, temperature control of the regenerative heater 121, and airflow control of the fans (first fan 112, second fan 124).

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a dew point adjustment method for adjusting the dew point of drying air supplied to a drying device using a dry dehumidifier (dehumidification rotor). The dew point adjustment method uses a dehumidification rotor to adjust the dew point of the circulating air from the drying device to be lower than the steady supply dew point, and humidifies the outlet dew point of the dehumidification rotor with a humidifier on the air supply side of the subsequent stage to adjust it to the steady supply dew point, and supplies the drying air to the drying device. The dew point adjustment method raises the temperature of the regeneration air passed through the dehumidification rotor by a regeneration air heater (regeneration heater) within a certain time when the drying state reaches a steady state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is an increasing demand that the air passed through the dehumidification rotor is only fresh outside air, not a mixture of outside air and return air. In this case, in the dew point adjustment method shown in Patent Document 1, since the dew point of the low dew point room is not considered, there is a risk that the dew point fluctuates violently 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 of a low dew point room even when only fresh outside air is passed through the dehumidification rotor.

Means for Solving the Problems

[0006] One aspect of this disclosure relates to an air conditioning system for supplying low-dew-point air into a room. The air conditioning system includes a dehumidifying rotor having a first area provided in a first duct connected to the room that adsorbs moisture contained in the outside air and discharges dehumidified air to the first duct, and a second area provided in a second duct connected to an exhaust port that discharges humid air containing the adsorbed moisture to the second duct; a regenerating heater provided on the inlet side of the second area in the second duct for heating the humid air; a fan provided on the outlet side of the second area in the second duct for sending the high-temperature, humid air heated by the regenerating heater toward the exhaust port; and controllers connected to the dehumidifying rotor, the regenerating heater, and the fan, respectively. The controller calculates a set dew point temperature relative to the first dew point temperature, which indicates the dew point temperature of the dehumidified air, based on changes in at least the second dew point temperature, which indicates the dew point temperature of the room. Then, in order to bring the first dew point temperature to follow the set dew point temperature, the controller performs at least one of the following controls: control of the rotation speed of the dehumidifying rotor, control of the temperature of the regenerative heater, and control of the airflow of the fan. [Effects of the Invention]

[0007] According to this disclosure, a set dew point temperature is calculated relative to a first dew point temperature, which indicates the dew point temperature of the dehumidified air, based on the change in a second dew point temperature, which indicates at least the indoor dew point temperature. At least one of the following controls is performed: rotation speed control of the dehumidifying rotor, temperature control of the regenerating heater, and airflow control of the fan, so that the first dew point temperature follows the set dew point temperature. 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 dehumidifying rotor. Therefore, the dew point in a low dew point room can be stably controlled. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing an example configuration of an air conditioning system according to an embodiment. [Figure 2] This is a block diagram showing an example of the functional configuration of a controller according to an embodiment. [Figure 3]This is a diagram illustrating an example of setting the dew point temperature according to the embodiment. [Figure 4] This figure illustrates an example of how the set dew point temperature changes according to the embodiment. [Figure 5] This flowchart shows an example of the processing of a controller for changing the set dew point temperature according to the embodiment. [Figure 6] This flowchart shows an example of the processing of a controller for changing the set dew point temperature according to the embodiment. [Modes for carrying out the invention]

[0009] The air conditioning system according to the embodiment of this disclosure will be described with reference to the attached drawings. In addition, elements common to each figure are denoted by the same reference numerals, and redundant explanations are omitted.

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

[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 referred to simply as the room). The dry dehumidifier 100 includes a first duct 131, a second duct 132, a dehumidifying rotor 101, a first fan 112, a second fan 124, a regenerating heater 121, a precooler 111, an aftercooler 114, and an afterheater 115.

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

[0013] The dehumidifying rotor 101 has a rotation mechanism that rotates in one direction and can rotate at any desired rotational speed. The dehumidifying rotor 101 is equipped with a power converter 102 (also simply called an inverter 102) for driving and controlling the rotation mechanism. The rotation mechanism is driven and controlled based on commands from the inverter 102. The inverter 102 is controlled by a controller 30, which will be described later.

[0014] The dehumidifying rotor 101 has a first area and a second area. The first area has the function of adsorbing moisture contained in the outside air drawn in from the outside air inlet via the first filter 110 and discharging dehumidified air. The second area has the function of discharging humid air containing the adsorbed moisture and the outside air drawn in from the outside air inlet via the second filter 120. The humid air may contain outside air drawn into the first duct 131. For example, if a 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 drawn into the first duct 131 is supplied to the second duct 132 via the first branch duct 131A.

[0015] The first fan 112 is located in the first duct 131 on the inlet side of the first area of ​​the dehumidifying rotor 101. It draws in outside air from the outside air port and sends it towards the inlet side of the first area, and also sends the outside air towards the second duct 132 via the first branch duct 131A. The first fan 112 is equipped with a power converter 113 (also simply referred to as 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. It sucks outside air from the outside air inlet and sends it toward the inlet side of the second area, and at the same time, sends out the high-temperature and high-humidity air exhausted from the outlet side of the second area and heated by the regeneration heater 121 toward the exhaust outlet. The second fan 124 includes a power conversion device 125 (also simply referred to as an inverter 125) for driving the fan. The inverter 125 is controlled by a controller 30 described later.

[0017] The regeneration heater 121 is provided on the inlet side of the second area of the dehumidification rotor 101 in the second duct 132 to heat the high-humidity air. The regeneration heater 121 includes a thyristor 122 for adjusting the power of the heater. The thyristor 122 is controlled by a controller 30 described later. The temperature of the high-humidity air heated by the regeneration heater 121 is monitored by a controller 30 described later. The temperature of the high-humidity air is measured by a thermometer 123 (also referred to as thermometer T) provided on the inlet side of the second area of the dehumidification rotor 101 in the second duct 132.

[0018] The pre-cooler 111 is provided between the first filter 110 and the first fan 112 in the first duct 131 to cool the outside air sucked from the outside air inlet. In this case, cold water for cooling the outside air may be supplied to the pre-cooler 111.

[0019] The after-cooler 114 cools the dehumidified air discharged from the dehumidification rotor 101. Thereby, the temperature rise of the dehumidified air can be suppressed. In this case, cold water for cooling the dehumidified air may be supplied to the after-cooler 114.

[0020] The after-heater 115 heats the dehumidified air cooled by the after-cooler 114. Thereby, the drying effect of the dehumidified air can be further improved.

[0021] The controller 30 controls the dry dehumidifier 100 to supply low-dew-point air to the low-dew-point chamber 20. Specifically, the controller 30 controls the operation of the dehumidifying rotor 101, the regenerative heater 121, the first fan 112, and the second fan 124 based on the second dew-point temperature 22 (also referred to as the second dew-point temperature DP2), which indicates the dew-point temperature of the low-dew-point chamber 20 (indoors), and the first dew-point temperature 11 (also referred to as the first dew-point temperature DP1), which indicates the dew-point temperature of the dehumidified air. Details of the various controls performed by the controller 30 will be described later.

[0022] 2. Example of Controller Functional Configuration Figure 2 is a block diagram showing an example of the functional configuration of the controller 30. The controller 30 includes an air supply dew point temperature setting control unit 200 and an equipment drive control unit 210. The air supply dew point temperature setting control unit 200 calculates the set air supply dew point temperature SP (hereinafter simply referred to as the set dew point temperature SP) for the first dew point temperature 11 based on changes in at least 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 represented, for example, as OFF, ON1, ON2, ON3. Details of the state of the set dew point temperature SP will be described 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 can be expressed, for example, as a reference value of the set dew point temperature SP (hereinafter referred to as reference SP), reference SP + 2°C DP, reference SP + 4°C DP, reference SP + 6°C DP, etc. Details of the setting of the set dew point temperature SP will be described later.

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

[0026] The equipment drive control unit 210 performs at least one of the following controls to cause the first dew point temperature 11 to follow the set dew point temperature SP: rotation speed control of the dehumidifying rotor 101, temperature control of the regenerating heater 121, airflow control of the first fan 112, and airflow control of the second fan 124.

[0027] For example, if the first dew point temperature 11 is higher than the set dew point temperature SP, the equipment drive control unit 210 will perform at least one of the following actions to increase the adsorption capacity of the dehumidifying rotor 101: increasing the rotation speed of the dehumidifying rotor 101, increasing the set temperature of the regenerating heater 121, or increasing the airflow of the fans (first fan 112, second fan 124). The set temperature of the regenerating heater 121 may be determined based on the temperature information of the humid air measured by the thermometer 123.

[0028] As another example, if the first dew point temperature 11 is lower than the set dew point temperature SP, the equipment drive control unit 210 will perform at least one of the following actions to reduce the adsorption capacity of the dehumidifying rotor 101: reduce the rotation speed of the dehumidifying rotor 101, lower the set temperature of the regenerating heater 121, or reduce the airflow of the fans (first fan 112, second fan 124).

[0029] Furthermore, the equipment drive control unit 210 generates and outputs a drive control signal (e.g., a PWM signal) for the inverter 102 when controlling the rotation speed of the dehumidifying rotor 101. When controlling the temperature of the regenerating heater 121, the equipment drive control unit 210 generates and outputs a drive control signal for the thyristor 122. When controlling the airflow of the fans (first fan 112, second fan 124), the equipment drive control unit 210 generates and outputs a drive control signal (e.g., a PWM signal) for the inverters (inverter 113, inverter 125).

[0030] In this way, by performing various controls by the controller 30, the first dew point temperature 11 can be made to follow the set dew point temperature SP. As a result, the second dew point temperature 22 can be made 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 Let's consider the case where only outside air passes through the dehumidifying rotor 101. The dew point temperature of the outside air fluctuates depending on the weather and season. For example, the dew point temperature of the outside air rises during rainy weather, but it is lower during the dry winter season. The controller 30 performs control to bring the first dew point temperature 11 closer to 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 dew point temperature of the outside air rises, such as during rainy weather, it may not be possible to stably bring the first dew point temperature 11 closer to the set dew point temperature SP due to the influence of disturbances (outside air dew point temperature). In this case, the control performance of the air conditioning system 1 may deteriorate.

[0032] According to this embodiment, even when affected by external disturbances (dew point temperature of the outside air), the set dew point temperature SP is changed in order to stably bring the first dew point temperature 11 to follow the set dew point temperature SP.

[0033] 3-2. Example Configuration Figure 3 is a diagram illustrating an example of setting 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, the second dew point temperature 22 changes based on the set dew point temperature SP. Based on this, the details of an example of setting the set dew point temperature SP will be explained.

[0034] First, let's consider the case where the second dew point temperature 22 decreases. There are three cases in which the second dew point temperature 22 decreases, as shown in Figure 3. Specifically, Case 1 is when the second dew point temperature 22 decreases to 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. Case 2 is when the second dew point temperature 22 decreases to 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. Case 3 is when the second dew point temperature 22 decreases to 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, let's consider the case where the second dew point temperature 22 rises. The second dew point temperature 22 is required to be controlled so as not to exceed the upper limit of the low dew point chamber 20. The upper limit 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 Figure 3. Specifically, Case 1 is when the second dew point temperature 22 rises above the first threshold (e.g., -42°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 OFF. Case 2 is when the second dew point temperature 22 rises above 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 ON2 to ON1. Case 3 is when the second dew point temperature 22 rises above the third threshold (e.g., -46°C DP). In this case, the set air supply dew point temperature state determination unit 201 switches the state of the set dew point temperature SP from ON3 to ON2.

[0036] The set air supply 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, if the state of the set dew point temperature SP is "OFF", the set air supply 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. If the state of the set dew point temperature SP is "ON1", the set air supply dew point temperature setting unit 202 sets the set dew point temperature SP as reference SP + 2°C DP (e.g., -48°C DP). If the state of the set dew point temperature SP is "ON2", the set air supply dew point temperature setting unit 202 sets the set dew point temperature SP as reference SP + 4°C DP (e.g., -46°C DP). If the state of the set dew point temperature SP is "ON3", the set air supply dew point temperature setting unit 202 sets the set dew point temperature SP as reference SP + 6°C DP (e.g., -44°C DP). In the example shown in Figure 3, the set air supply 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 air supply dew point temperature setting unit 202 may set the set dew point temperature SP in increments of 1°C DP, or it may set the set dew point temperature SP in increments greater than 2°C DP.

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

[0038] 3-3. Examples of Changes 3-3-1. Example 1 Figure 4 is a diagram illustrating an example of the change in the set dew point temperature SP according to the embodiment. First, let's consider the case where the second dew point temperature 22 decreases. 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 Figure 4, when the second dew point temperature 22 decreases, 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] If the state of the set dew point temperature SP is "OFF" and the second dew point temperature 22 is below the second threshold (e.g., -44°C DP), that is, if the second dew point temperature 22 has dropped 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 "ON1". Subsequently, the controller 30 sets the set dew point temperature SP as SP + 2°C DP (e.g., -48°C DP). In other words, the controller 30 raises the set dew point temperature SP by 2°C DP to suppress the drop in the second dew point temperature 22. As a result of the set dew point temperature SP rising by 2°C DP, the first dew point temperature 11 also rises by 2°C DP to follow the set dew point temperature SP. This reduces the slope of the second dew point temperature 22, thereby suppressing the drop in the second dew point temperature 22.

[0040] When the state of the set dew point temperature SP is "ON1" and the second dew point temperature 22 falls below the third threshold (e.g., -46°C DP), that is, when the second dew point temperature 22 has dropped 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 "ON2". Subsequently, the controller 30 sets the set dew point temperature SP as SP + 4°C DP (-46°C DP). In other words, the controller 30 further increases the set dew point temperature SP by 2°C DP to suppress the drop in the second dew point temperature 22. As the set dew point temperature SP has increased by 2°C DP, the first dew point temperature 11 also increases by 2°C DP to follow the set dew point temperature SP. This further reduces the slope of the second dew point temperature 22, further suppressing the drop in the second dew point temperature 22.

[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, then the second dew point temperature 22 can be said to be stable. In this case, the controller 30 maintains the set dew point temperature SP at SP + 4°C DP (e.g., -46°C DP).

[0042] Next, let's consider the case where the second dew point temperature 22 rises. For example, as shown in Figure 4, when the state of the set dew point temperature SP is "ON2", if the second dew point temperature 22 becomes greater than or equal to 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 becomes 2°C DP or greater, the controller 30 determines the state of the set dew point temperature SP to "ON1". Subsequently, the controller 30 sets the set dew point temperature SP as SP + 2°C DP (e.g., -48°C DP). In other words, the controller 30 lowers the set dew point temperature SP by the deviation of 2°C DP so that the second dew point temperature 22 does not exceed the upper limit 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 also 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, preventing 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 (or similar) provided in the controller 30 can be suppressed, allowing the air conditioning system 1 to operate efficiently.

[0043] In the example shown in Figure 4, the state of the set dew point temperature SP changes in the order of OFF, ON1, ON2, 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 stepwise changes in the set dew point temperature SP are varied 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 unit 200) changes the set dew point temperature SP in steps based on the change in the second dew point temperature 22. Alternatively, the controller 30 (supply air dew point temperature setting control unit 200) changes the set dew point temperature SP in steps based on the change in the deviation between the second dew point temperature 22 and the target room dew point temperature. This allows the controller 30 to control the second dew point temperature 22 so that it approaches the target room dew point temperature within a range where it does not exceed the upper limit (-40°C DP) of the low dew point chamber 20. Therefore, even when only fresh outside air is passed through the dehumidifying rotor 101, the dew point in the low dew point chamber 20 can be stably controlled.

[0045] 3-3-2. Second Example Consider the case where the set dew point temperature SP is changed in steps. In this case, the second dew point temperature 22 may repeatedly decrease and increase, and the second dew point temperature 22 may become unstable. This phenomenon is also called hunting. In particular, if the set dew point temperature SP is changed while the second dew point temperature 22 is decreasing, hunting may occur if the second dew point temperature 22 becomes lower than the first dew point temperature 11. 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] In the second example, the controller 30 controls the timing of gradually changing the set dew point temperature SP as described in the first example. Specifically, as shown in Figure 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 has dropped 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. In other words, the controller 30 (set air supply 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 predetermined time. The predetermined time is set, for example, by a timer provided in the controller 30.

[0047] Furthermore, as shown in Figure 4, when the state of the set dew point temperature SP is "ON1" and the second dew point temperature 22 falls below the third threshold (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 raises the set dew point temperature SP by another 2°C DP after a predetermined time has elapsed. In other words, the controller 30 (set air supply dew point temperature state determination unit 201) delays the timing of raising the set dew point temperature SP by another 2°C DP, that is, the timing of switching the state of the set dew point temperature SP from "ON1" to "ON2".

[0048] In this manner, if the temperature difference between the second dew point temperature 22 and the set dew point temperature SP falls below a predetermined temperature (e.g., less than 2°C DP) as the set dew point temperature SP decreases, the controller 30 maintains the set dew point temperature SP until a predetermined time has elapsed. After the predetermined time has elapsed, the controller 30 raises the set dew point temperature SP. This prevents the second dew point temperature 22 from falling below the first dew point temperature 11, thereby preventing the second dew point temperature 22 from hunting. Therefore, compared to the effects of the first example described above, it can be expected that the dew point in the low dew point chamber 20 can be controlled more stably.

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

[0050] Furthermore, the control system in the controller 30 according to the first and second examples may be a cascade control system configured by providing a control loop (also called a major loop) inside a control loop (also called a major loop) that causes the second dew point temperature 22 to follow the target room dew point temperature, and a control loop (also called a minor loop) that causes the first dew point temperature 11 to gradually follow the set dew point temperature SP in accordance with the change in the set dew point temperature SP.

[0051] 3-4. Processing Example Figures 5 and 6 are flowcharts illustrating an example of the processing performed by the controller 30 for changing the set dew point temperature SP according to the embodiment. Figures 5 and 6 show an example of the process in which the second dew point temperature 22, which is near the target indoor dew point temperature (-42°C DP), decreases, and the set dew point temperature SP is changed in order 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 the 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 raises 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 reference SP + 2°C DP (-48°C DP). The process then 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 the OFF position. 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). After that, the process ends.

[0058] When the state of the set dew point temperature SP is not OFF, for example, when the state of the set dew point temperature SP is ON1 and step S160, described later, is "Yes". In this case, to prevent the second dew point temperature DP2 from rising and exceeding the upper limit of the low dew point chamber 20, the controller 30 switches the state of the set dew point temperature SP to OFF and sets the set dew point temperature SP as reference SP-0℃DP (-50℃DP). This prevents the second dew point temperature DP2 from exceeding the upper limit 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 as reference SP + 4°C DP (-46°C DP). After that, 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 as reference SP + 6°C DP (-44°C DP). After that, 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. Variations The set dew point temperature SP described above has a dead zone, but is not limited to that. 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 or curved). 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 abruptly.

[0066] According to a modified embodiment, the controller 30 controls the timing of changing the set dew point temperature SP using a timer when there is no dead zone at 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…Dehumidifying 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 into a room, A dehumidifying rotor having a first area provided in a first duct connected to the room that adsorbs moisture contained in the outside air and discharges dehumidified air to the first duct, and a second area provided in a second duct connected to an exhaust port that discharges humid air containing the adsorbed moisture to the second duct, The second duct includes a regenerative heater provided on the inlet side of the second area for heating the humid air, The second duct includes a fan provided on the outlet side of the second area, which sends the high-temperature, high-humidity air, heated by the regenerating heater, toward the exhaust port, The system comprises a controller connected to the dehumidifying rotor, the regenerating heater, and the fan, respectively. The aforementioned controller, Based on the change in the second dew point temperature, which indicates the dew point temperature inside the room, the set dew point temperature is calculated relative to the first dew point temperature, which indicates the dew point temperature of the dehumidified air. The system is configured to perform at least one of the following controls: rotation speed control of the dehumidifying rotor, temperature control of the regenerating heater, and airflow control of the fan, so that the first dew point temperature follows the set dew point temperature. An air conditioning system characterized by the following features.

2. An air conditioning system according to claim 1, The controller changes the set dew point temperature in steps based on the change in the second dew point temperature. An air conditioning system characterized by the following features.

3. An air conditioning system according to claim 1, The controller changes the set dew point temperature in steps based on the change in the deviation between the second dew point temperature and the target dew point temperature in the room. An air conditioning system characterized by the following features.

4. An air conditioning system according to claim 2 or 3, The aforementioned stepwise change includes a decrease in the set dew point temperature, The aforementioned controller, If the temperature difference between the second dew point temperature and the set dew point temperature falls below a predetermined temperature due to the decrease in the set dew point temperature, the set dew point temperature is maintained until a predetermined time has elapsed. The system is configured to raise the set dew point temperature after the predetermined time has elapsed. An air conditioning system characterized by the following features.

5. An air conditioning system according to claim 2 or 3, The aforementioned stepwise change includes an increase in the set dew point temperature. The aforementioned controller, The system is configured to lower the set dew point temperature if, as the second dew point temperature rises, the temperature difference between the second dew point temperature and the set dew point temperature exceeds a predetermined temperature. An air conditioning system characterized by the following features.

6. An air conditioning system according to claim 1, The aforementioned controller, If the first dew point temperature is higher than the set dew point temperature, at least one of the following is performed to increase the adsorption capacity of the dehumidifying rotor: increasing the rotation speed of the dehumidifying rotor, increasing the set temperature of the regenerating heater, and increasing the airflow of the fan. If the first dew point temperature is lower than the set dew point temperature, the system is configured to reduce the adsorption capacity of the dehumidifying rotor by reducing the rotation speed of the dehumidifying rotor, lowering the set temperature of the regenerating heater, and reducing the airflow of the fan, by performing at least one of these actions. An air conditioning system characterized by the following features.

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