WO2018173120A1

WO2018173120A1 - Dehumidifier

Info

Publication number: WO2018173120A1
Application number: PCT/JP2017/011212
Authority: WO
Inventors: 達也 ▲雑▼賀; 圭吾岡島; 智典小島
Original assignee: 三菱電機株式会社
Priority date: 2017-03-21
Filing date: 2017-03-21
Publication date: 2018-09-27
Also published as: JPWO2018173120A1; JP6843227B2; CN110418921B; CN110418921A

Abstract

This dehumidifier is provided with: a refrigerant circuit wherein a compressor, a condenser, an expansion device, and an evaporator are connected sequentially by piping; a blower for causing air to flow through an air passage which extends from a space to be dehumidified, passes through the evaporator and the condenser, and returns to the space to be dehumidified; an inlet humidity sensor provided at the inlet of the air passage; an evaporation temperature sensor for measuring the evaporation temperature of the evaporator; and a control unit. The control unit is configured such that, when the evaporation temperature is higher than the freezing temperature of water, the control unit controls the operation frequency of the compressor according to the difference between target hummidity and actually measured humidity.

Description

Dehumidifier

The present invention relates to a dehumidifier including a compressor that compresses and discharges a refrigerant.

As an example of a conventional dehumidifier, a compressor, an outdoor heat exchanger and a first indoor heat exchanger that function as a condenser, a second indoor heat exchanger that functions as an evaporator, and an outdoor heat exchanger An air conditioner having a blower for supplying outside air is disclosed (for example, see Patent Document 1).

In Patent Document 1, when the air conditioner performs a dehumidifying operation, in order to maintain the room temperature at the set temperature, when the room temperature becomes higher than the set temperature, the rotation speed of the blower is increased and the room temperature becomes lower than the set temperature. It is disclosed that the rotational speed of the blower is reduced.

JP-A-3-31640

In the air conditioner disclosed in Patent Document 1, the heat exchange performance can be adjusted only by adjusting the rotational speed of the blower, but the dehumidification capability is improved so that frost formation does not occur in the evaporator only by adjusting the air volume of the blower. It is difficult.

The present invention has been made to solve the above-described problems, and provides a dehumidifier that improves the dehumidifying capacity so that frosting does not occur in the evaporator.

The dehumidifier according to the present invention includes a refrigerant circuit in which a compressor, a condenser, an expansion device, and an evaporator are connected in order, and a refrigerant circulates, and the dehumidification from a dehumidifying target space via the evaporator and the condenser. A blower that circulates air through an air passage that returns to the target space, an inlet humidity sensor that is provided at an inlet of the air passage and measures the humidity of the air, an evaporation temperature sensor that measures the evaporation temperature of the evaporator, and the compression And a controller for controlling the expansion device and the blower, and the controller controls the humidity between the target humidity and the measured value of the inlet humidity sensor in a range where the evaporation temperature is higher than the freezing temperature of water. The operating frequency of the compressor is controlled according to the difference.

In order to prevent the evaporation temperature from dropping to the freezing temperature of water, the present invention controls the operating frequency of the compressor in accordance with the humidity difference between the target humidity and the actually measured humidity to adjust the evaporation temperature. It is possible to improve the dehumidifying ability while suppressing the occurrence of.

It is a refrigerant circuit figure which shows one structural example of the dehumidifier which concerns on Embodiment 1 of this invention. It is a block diagram which shows the example of 1 structure of the control part shown in FIG. It is an air diagram which shows the change of the temperature and humidity of air. It is a flowchart which shows an example of the operation | movement procedure of the dehumidifier shown in FIG. It is a flowchart which shows the other example of the operation | movement procedure of the dehumidifier shown in FIG. It is a graph which shows the relationship between humidity and time at the time of the driving | operation of the dehumidifier shown in FIG. It is a refrigerant circuit diagram which shows one structural example of the dehumidifier which concerns on Embodiment 2 of this invention. It is a flowchart which shows an example of the operation | movement procedure of the dehumidifier shown in FIG. It is a graph which shows an example of the capability correction coefficient which shows the dehumidification capability fall by defrosting.

Embodiment 1 FIG.
The structure of the dehumidifier of this Embodiment 1 is demonstrated. FIG. 1 is a refrigerant circuit diagram illustrating a configuration example of a dehumidifier according to Embodiment 1 of the present invention. As shown in FIG. 1, the dehumidifier 1 includes a compressor 10, a condenser 20, an expansion device 30, an evaporator 40, a blower 60, and a control unit 50. The compressor 10, the condenser 20, the expansion device 30 and the evaporator 40 are sequentially connected by a pipe 15 and constitute a refrigerant circuit in which the refrigerant circulates. The condenser 20 and the evaporator 40 are provided with a plurality of fins for allowing the refrigerant to exchange heat with air.

The blower 60 sucks air from the dehumidification target space and distributes the sucked air to the air path 61 that returns to the dehumidification target space via the evaporator 40 and the condenser 20. The air flowing through the air path 61 passes through the gaps of the plurality of fins in each of the evaporator 40 and the condenser 20. An inlet humidity sensor 71 that measures the humidity of air sucked into the dehumidifier 1 from the dehumidifying target space is provided at the inlet of the air passage 61. An evaporating temperature sensor 45 that measures the evaporating temperature of the refrigerant is provided in the refrigerant outlet pipe 15 of the evaporator 40.

The inlet humidity sensor 71, the evaporation temperature sensor 45, and the expansion device 30 are connected to the control unit 50 via signal lines. The inlet humidity sensor 71 outputs the humidity H1 as a measurement value to the control unit 50 via a signal line. The evaporation temperature sensor 45 outputs the evaporation temperature Te as a measurement value to the control unit 50 via a signal line. The compressor 10 is provided with an inverter (not shown), and the blower 60 is provided with a fan motor (not shown). The inverter and the fan motor are connected to the control unit 50 via signal lines. .

The compressor 10 compresses the refrigerant sucked from the evaporator 40 and discharges it to the condenser 20. The expansion device 30 expands the refrigerant by reducing the pressure of the refrigerant flowing from the condenser 20 to the evaporator 40. The evaporator 40 cools the air by heat exchange between the air sucked from the dehumidification target space and the refrigerant. The condenser 20 heats the air by heat exchange between the air cooled by the evaporator 40 and the refrigerant. In the dehumidifier 1, the condenser 20 functions as a reheater.

FIG. 2 is a block diagram illustrating a configuration example of the control unit illustrated in FIG. The control unit 50 is, for example, a microcomputer. As illustrated in FIG. 2, the control unit 50 includes a memory 51 that stores a program and a CPU (Central Processing Unit) 52 that executes processing according to the program.

The control unit 50 controls the refrigeration cycle in the refrigerant circuit by controlling the operating frequency of the compressor 10 and the blower 60 and controlling the opening degree of the expansion device 30. Based on the evaporation temperature acquired from the evaporation temperature sensor 45, the control unit 50 controls the opening degree of the expansion device 30 so that the degree of superheat becomes a set value. The control unit 50 controls the operating frequency of the compressor 10 based on the value of the humidity H1 acquired from the inlet humidity sensor 71 in a range where the evaporation temperature is higher than the freezing temperature of water. Although the freezing temperature of water varies depending on the pressure, in the first embodiment, the case where the freezing temperature of water is 0 ° C. will be described.

Although not shown in FIG. 1, a drain pan for collecting condensed water on the surface of the evaporator 40 may be provided under the evaporator 40. Moreover, although the control part 50 demonstrated by the case where the evaporation temperature was acquired from the evaporation temperature sensor 45 provided in the refrigerant | coolant exit side of the evaporator 40, the installation place of the evaporation temperature sensor 45 is on the refrigerant | coolant exit side of the evaporator 40. It may be not only the refrigerant inlet side but also both the refrigerant inlet and the refrigerant outlet. Furthermore, a suction pressure sensor that measures the pressure on the refrigerant suction side of the compressor 10 may be provided, and the control unit 50 may calculate the evaporation temperature using the measured value of the suction pressure sensor.

Next, the operation of the dehumidifier 1 according to the first embodiment will be described with reference to FIG. The control part 50 starts the compressor 10 and the air blower 60, and sets the opening degree of the expansion apparatus 30 to an initial value. The refrigerant repeats a cycle of returning from the compressor 10 to the compressor 10 through the pipe 15 in the order of the condenser 20, the expansion device 30, and the evaporator 40.

The air sucked into the air passage 61 from the space to be dehumidified passes through the evaporator 40. At that time, the air passing through the low-temperature evaporator 40 is cooled to the dew point temperature or lower by exchanging heat with the evaporator 40. As a result, the surface of the evaporator 40 is condensed and the absolute humidity of the air is reduced. When the absolute humidity is lowered, the air is heated by exchanging heat with the high-temperature condenser 20 when passing through the condenser 20. The air passing through the condenser 20 becomes dry air having a reduced relative humidity when heated. By releasing this dried air from the dehumidifier 1 to the dehumidifying target space, the dehumidifying target space can be dehumidified.

FIG. 3 is an air diagram showing changes in air temperature and humidity. The vertical axis in FIG. 3 indicates absolute humidity, and the horizontal axis indicates the dry bulb temperature of air. Changes in the temperature and humidity of the air flowing through the air passage 61 will be described with reference to FIG. The solid line arrows shown in FIG. 3 indicate changes in air temperature and humidity. A state Sin illustrated in FIG. 3 indicates a state of air sucked into the dehumidifier 1 at the inlet of the air passage 61. A state Sout shown in FIG. 3 indicates a state of air blown out from the dehumidifier 1 at the outlet of the air passage 61.

The temperature of the air sucked into the dehumidifier 1 is lowered by the evaporator 40 from the state Sin to the outdoor temperature (state Sv1 shown in FIG. 3). The humidity of the air decreases along the line of 100% relative humidity to a value where the absolute humidity corresponds to the state Sv2. When the air changes from the state Sv1 to the state Sv2, the temperature also decreases, but is warmed when passing through the condenser 20 and rises to a temperature corresponding to the state Sout. Thereafter, the air in the state Sout in which the relative humidity is lower than that in the state Sin is released from the dehumidifier 1 to the dehumidifying target space.

In the first embodiment, the control unit 50 may compare the actually measured humidity with the target humidity and control the operating frequency of the compressor 10 as follows. FIG. 4 is a flowchart showing an example of an operation procedure of the dehumidifier shown in FIG.

The control unit 50 acquires measured values from the inlet humidity sensor 71 and the evaporation temperature sensor 45 at a constant cycle (step S101), and determines whether or not the evaporation temperature Te is higher than 0 ° C. (step S102). Let time of one cycle be Δt1. If it is determined in step S102 that the evaporation temperature Te is 0 ° C. or lower, the control unit 50 proceeds to step S105 described later. When the evaporation temperature Te is higher than 0 ° C., the control unit 50 compares the target humidity H0 with the humidity H1 _i measured by the inlet humidity sensor 71. i is a positive integer. The controller 50 controls the operating frequency of the compressor 10 based on the humidity difference ΔH _i between the target humidity H0 and the humidity H1 _i .

In the example of the procedure shown in FIG. 4, in step S103, the control unit 50, the humidity difference [Delta] H _i is equal to or greater than the first threshold TH1. The first threshold TH1 is stored in the memory 51 in advance. It determined in step S103, when the humidity difference [Delta] H _i is greater than the first threshold value TH1, the control unit 50 increases the operating frequency of the compressor 10 (step S104). On the other hand, the result of the determination in step S102, when the humidity difference [Delta] H _i is equal to or less than the first threshold value TH1, the control unit 50 maintains unchanged the operating frequency of the compressor 10 (step S105). In step S104, the control unit 50, the larger the difference between the humidity difference [Delta] H _i and the first threshold TH1, it may increase the value to increase the operating frequency of the compressor 10. In step S105, the control unit 50 may decrease the operating frequency of the compressor 10.

If the control unit 50 controls the dehumidifier 1 according to the procedure shown in FIG. 4, the dehumidifying capacity is determined in accordance with the difference between the actually measured humidity and the target humidity in the dehumidifying target space in a range where the evaporator 40 is not frosted. Can be improved. As a result, the humidity of the dehumidifying target space can be made to reach the target humidity more quickly.

Furthermore, in the first embodiment, the control unit 50 may control the operating frequency of the compressor 10 as follows based on the time change of the actually measured humidity. FIG. 5 is a flowchart showing another example of the operation procedure of the dehumidifier shown in FIG. FIG. 6 is a graph showing the relationship between humidity and time during operation of the dehumidifier shown in FIG. The vertical axis in FIG. 6 indicates relative humidity, and the horizontal axis indicates time. In the flowchart shown in FIG. 5, the same step number is assigned to the same process as the process shown in FIG. 4, and detailed description thereof is omitted.

In step S101, the control unit 50 stores the humidity H1 _i-1 and the humidity H1 _i acquired before and after the time Δt1 in the memory 51 in the period of the time Δt1. It determined in step S103, when the humidity difference [Delta] H _i is equal to or less than the first threshold value TH1, the control unit 50, the humidity of the humidity _{H1 i-1} and the target humidity H0 measured the previous time _{t i-1} first humidity difference [Delta] H _i-1 is the difference, compares the magnitude of the second humidity difference [Delta] H _i is the humidity difference between the current time t _i humidity H1 _i and target humidity H0 measured in ( Step S111).

If it is determined in step S111 that ΔH _i <ΔH _i−1 , the control unit 50 decreases the operating frequency of the compressor 10 according to the magnitude of the second humidity difference ΔH _i (step S112). For example, as the ratio of the second humidity difference ΔH _i to the _first humidity difference ΔH _i−1 is smaller, the control unit 50 may increase the ratio of decreasing the operating frequency of the compressor 10. On the other hand, if ΔH _i ≧ ΔH _i−1 as a result of the determination in step S111, the control unit 50 maintains the operating frequency of the compressor 10 without being changed (step S113).

Also in the flowchart shown in FIG. 5, if the evaporation temperature Te is 0 ° C. or lower as a result of the determination in step S102, the control unit 50 performs control to maintain the operating frequency of the compressor 10 (step S113). Further, control for reducing the operation frequency may be performed.

If the control unit 50 controls the dehumidifier 1 according to the procedure shown in FIG. 5, it is possible to reduce the operating frequency of the compressor 10 while ensuring the necessary dehumidifying capacity, and to prevent the dehumidifying capacity from becoming excessive. . As a result, the power consumption of the dehumidifier 1 is reduced and energy saving operation can be performed. In addition, with reference to FIG. 4 and FIG. 5, although the period when the control part 50 acquires a measured value from the entrance humidity sensor 71 was the same, these periods differed in the flowchart shown in FIG. 4 and FIG. May be.

The dehumidifier 1 according to the first embodiment includes a refrigerant circuit in which the compressor 10, the condenser 20, the expansion device 30 and the evaporator 40 are connected in order through a pipe, and the dehumidification target space via the evaporator 40 and the condenser 20. Then, a blower 60 that circulates air through the air passage 61 that returns to the dehumidifying target space, an inlet humidity sensor 71 provided at the inlet of the air passage 61, an evaporation temperature sensor 45 that measures the evaporation temperature of the evaporator 40, and control The controller 50 controls the operating frequency of the compressor 10 in accordance with the humidity difference between the target humidity and the actually measured humidity in a range where the evaporation temperature is higher than the freezing temperature of water.

According to the first embodiment, in order to adjust the evaporation temperature by controlling the operating frequency of the compressor 10 according to the humidity difference between the target humidity and the actually measured humidity so that the evaporation temperature does not decrease to the freezing temperature of water. The dehumidifying ability can be improved while suppressing the formation of frost on the evaporator 40. Further, if the operating frequency of the compressor 10 is increased as the humidity difference value is increased, the humidity in the dehumidifying target space can be made to reach the target humidity sooner.

In the first embodiment, the control unit 50 acquires the measurement value from the inlet humidity sensor at a constant cycle, the first humidity difference that is the difference between the previously acquired measurement value and the target humidity, and the measurement acquired this time. The second humidity difference that is the difference between the value and the target humidity is compared, and when the second humidity difference is smaller than the first humidity difference, the operating frequency of the compressor 10 may be reduced. In this case, the necessary dehumidifying capacity can be ensured and the dehumidifying capacity can be suppressed from becoming excessive. As a result, the power consumption of the dehumidifier 1 is reduced and energy saving operation can be performed.

Embodiment 2. FIG.
In the first embodiment, the dehumidifier 1 increases the operating frequency of the compressor 10 to improve the refrigerating capacity of the evaporator 40 so that the evaporation temperature does not fall to the freezing temperature of water. However, even if the evaporating temperature does not reach the freezing temperature of water, the refrigerating capacity of the evaporator 40 decreases when the evaporating temperature approaches the freezing temperature of water. In the second embodiment, dehumidification and defrost are performed in a well-balanced manner to improve the dehumidification capability.

The configuration of the dehumidifier of the second embodiment will be described. In the second embodiment, detailed description of the same configuration as that described in the first embodiment is omitted. FIG. 7 is a refrigerant circuit diagram illustrating a configuration example of the dehumidifier according to Embodiment 2 of the present invention.

As shown in FIG. 7, the dehumidifier 1a has a configuration in which an inlet temperature sensor 72, an outlet humidity sensor 81, and an outlet temperature sensor 82 are added as compared with the configuration shown in FIG. The inlet temperature sensor 72, the outlet humidity sensor 81, and the outlet temperature sensor 82 are connected to the control unit 50 through signal lines.

The inlet temperature sensor 72 is provided at the inlet of the air passage 61. The inlet temperature sensor 72 measures the temperature of the air sucked into the dehumidifier 1a from the dehumidification target space. The inlet temperature sensor 72 outputs the temperature T1 as a measurement value to the control unit 50 via a signal line. The outlet humidity sensor 81 and the outlet temperature sensor 82 are provided at the outlet of the air passage 61. The outlet humidity sensor 81 measures the humidity of the air blown from the dehumidifier 1a to the dehumidifying target space. The outlet humidity sensor 81 outputs the humidity H2 as a measurement value to the control unit 50 via a signal line. The outlet temperature sensor 82 measures the temperature of the air blown from the dehumidifier 1a to the dehumidifying target space. The outlet temperature sensor 82 outputs the temperature T2 as a measurement value to the control unit 50 via a signal line.

The control unit 50 prohibits increasing the operating frequency of the compressor 10 according to the humidity difference between the target humidity and the measured value of the inlet humidity sensor 71 when frosting suppression control is set and a certain condition is satisfied. Then, the frosting suppression control for maintaining or reducing the operation frequency of the compressor 10 is started. For example, the frosting suppression control may be set by a user operating a remote controller (not shown), and the user switches a switch (not shown) provided in the dehumidifier 1a from an off state to an on state. You may go. The constant condition is, for example, that the evaporation temperature Te is lowered to a temperature just before frosting occurs in the evaporator 40. Hereinafter, control for increasing the operating frequency of the compressor 10 in accordance with the humidity difference between the target humidity and the measured value of the inlet humidity sensor 71 is referred to as normal dehumidification control.

The memory 51 of the control unit 50 includes air diagram data, dehumidification capability diagram data that differs depending on the model of the dehumidifier 1a, and capability correction that is a coefficient that corrects a humidity reduction in the dehumidification capability diagram. The coefficient is memorized. FIG. 3 described in the first embodiment shows a part of a graph of an air diagram. After starting the frost suppression control, the control unit 50 simply calculates the dehumidifying capacity Q1 using the values of the humidity H1, the temperature T1, the humidity H2, and the temperature T2. Moreover, the control part 50 calculates | requires the rated dehumidification capability Q2 based on the model dehumidification capability which is a dehumidification capability determined by the rated capability for every model. When the dehumidifying capacity Q1 is smaller than the rated dehumidifying capacity Q2, the control unit 50 releases the frosting suppression control and resumes the normal dehumidifying control.

Next, the operation of the dehumidifier 1a according to the second embodiment will be described. FIG. 8 is a flowchart showing an example of an operation procedure of the dehumidifier shown in FIG. As an initial state, the control unit 50 performs normal dehumidification control.

In the control unit 50, the frost suppression control is set to the on state by the user. The controller 50 continues the normal dehumidification control until a certain condition is satisfied even when the frost suppression control is set to the on state. The control unit 50 acquires the evaporation temperature Te from the evaporation temperature sensor 45 at a period of time Δt2 (step S201). The controller 50 determines whether or not the evaporation temperature Te is 4.5 ° C. or less (step S202). As a result of the determination in step S202, when the evaporation temperature Te is 4.5 ° C. or lower, the control unit 50 stops the normal dehumidification control and executes the frosting suppression control (step S203). By prohibiting an increase in the operating frequency of the compressor 10, it is possible to suppress the evaporation temperature Te from further decreasing. On the other hand, if the result of determination in step S202 is that the evaporation temperature Te is higher than 4.5 ° C., the control unit 50 returns to step S201 and maintains normal dehumidification control.

In step S203, an increase in the operating frequency of the compressor 10 is prohibited, but it is also conceivable that the evaporation temperature Te further decreases. The controller 50 determines whether or not the evaporation temperature Te is 3.5 ° C. or less (step S204). In the determination in step S204, when the evaporation temperature Te becomes 3.5 ° C. or lower, the control unit 50 decreases the operating frequency of the compressor 10. The controller 50 increases the evaporation temperature Te by reducing the operating frequency of the compressor 10 and controls the evaporator 40 so as not to form frost. On the other hand, if the evaporation temperature Te is higher than 3.5 ° C. as a result of the determination in step S204, the control unit 50 maintains the operating frequency of the compressor 10 and proceeds to step S206.

Subsequently, the control unit 50 determines whether or not the time Δt3 has elapsed since the operating frequency of the compressor 10 was maintained or decreased (step S206). Since there is a time lag until the effect of control on the operating frequency of the compressor 10 occurs in the evaporator 40, it is desirable that the time Δt3 is longer than the time Δt2 that determines the frequency of monitoring the evaporation temperature. Until the time Δt3 has elapsed, the control unit 50 repeats the determination of step S204, and when the evaporation temperature Te does not become higher than 3.5 ° C., the control frequency of the compressor 10 is decreased (step S205). When the control unit 50 continues to decrease the operating frequency of the compressor 10 by the frost suppression control, the evaporation temperature Te increases and the temperature difference between the air and the evaporator 40 decreases. In this case, the refrigerating capacity of the evaporator 40 is lowered and the dehumidifying capacity is also lowered.

In the evaporator 40, the refrigeration capacity is reduced as the heat exchange performance is deteriorated due to the frost formation, but the refrigeration capacity is reduced by executing the frost suppression control for the defrosting time for melting the frost. Recover. However, if the operating frequency of the compressor 10 is continuously reduced, the frosting suppression control may be maintained even though the refrigeration capacity is recovered. In this case, the dehumidifying ability is excessively reduced. Therefore, it is necessary to compare the recovery of the refrigeration capacity and the decrease in the refrigeration capacity in the evaporator 40 by the frost suppression control to determine the switching between the frost suppression control and the normal dehumidification control.

The control unit 50 simply calculates the dehumidifying ability Q1 that has decreased due to a decrease in the operating frequency of the compressor 10 as follows. Referring to the air diagram shown in FIG. 3, the state of the air passing through the air passage 61 transitions along the path indicated by the solid line arrow shown in FIG. 3. Therefore, the control unit 50 refers to the air diagram and uses the humidity H1 acquired from the inlet humidity sensor 71 and the temperature T1 acquired from the inlet temperature sensor 72 to determine the absolute humidity of the air at the inlet of the air passage 61. The inlet absolute humidity AHin is calculated. Also on the outlet side of the air passage 61, the control unit 50 refers to the air diagram, and uses the humidity H2 acquired from the outlet humidity sensor 81 and the temperature T2 acquired from the outlet temperature sensor 82 to output the air passage 61 from the outlet. The outlet absolute humidity AHout, which is the absolute humidity of the air, is calculated.

Furthermore, the control unit 50 calculates the absolute humidity difference ΔAH = (inlet absolute humidity AHin−outlet absolute humidity AHout) using the inlet absolute humidity AHin and the outlet absolute humidity AHout. The controller 50 calculates the dehumidification amount per unit time by multiplying the calculated absolute humidity difference ΔAH by the air volume determined for each model of the dehumidifier 1a, and simply calculates the dehumidification capability Q1.

Next, the control unit 50 obtains the rated dehumidifying capacity Q2 from the model dehumidifying capacity determined by the rated capacity for each model of the dehumidifier 1a as follows. The model dehumidifying capacity is represented by a dehumidifying capacity diagram, for example. The rated dehumidifying capacity Q2 in consideration of frost formation and defrosting needs to be multiplied by a capacity correction coefficient to the dehumidifying capacity diagram of the dehumidifier 1a. The capacity correction coefficient is a coefficient for correcting a capacity decrease depending on humidity with respect to the model dehumidifying capacity. FIG. 9 is a graph showing an example of a capability correction coefficient indicating a dehumidification capability decrease due to defrosting. In FIG. 9, the vertical axis represents temperature, and the horizontal axis represents relative humidity.

The capacity correction coefficient varies depending on the temperature and humidity conditions, but as shown in FIG. 9, the capacity correction coefficient is a coefficient depending on the humidity with respect to the dehumidification capacity diagram. The control unit 50 reads out the capability correction coefficient corresponding to the humidity H1 at the time of measurement from the capability correction coefficient shown in FIG. 9, and multiplies the read capability correction coefficient by the data of the dehumidification capability diagram stored in the memory 51. The rated dehumidifying capacity Q2 is calculated in consideration of frost formation and defrosting. In the example of the procedure shown in FIG. 8, it is assumed that the humidity H1 is in the range of 60% to 70%. In this case, referring to FIG. 9, the capability correction coefficient is 0.6.

As described above, the control unit 50 performs the dehumidifying ability Q1 when the operating frequency of the compressor 10 is decreased by the frosting suppression control, the frosting and the defrosting under the humidity H1 measured by the inlet humidity sensor 71. When the rated dehumidifying capacity Q2 is calculated, the dehumidifying capacity Q1 is compared with the rated dehumidifying capacity Q2. In step S207 shown in FIG. 8, the control unit 50 determines whether or not the dehumidifying capacity Q1 is equal to or higher than the rated dehumidifying capacity Q2. As a result of the determination in step S207, if Q1 ≧ Q2, the control unit 50 continues the frosting suppression control and returns to step S201. On the other hand, if Q1 <Q2 as a result of the determination in step S207, the control unit 50 cancels the frosting suppression control and resumes the normal dehumidification control (step S208).

In the procedure described with reference to FIG. 8, the constant condition is described when the evaporation temperature Te is 4.5 ° C. or lower, but the value of the evaporation temperature Te is not limited to 4.5 ° C. It may be 5 ° C. Further, the certain condition is not limited to the evaporation temperature Te, but may be other conditions. The time Δt2 may be the same as or different from the time Δt1 of the first embodiment.

In the dehumidifier 1a of the second embodiment, the control unit 50 prohibits increasing the operating frequency of the compressor 10 when the evaporation temperature falls to a predetermined temperature higher than the freezing temperature of water, and compresses Frost suppression control for maintaining or reducing the operating frequency of the machine 10 is executed. The predetermined temperature at which the evaporation temperature is higher than the freezing temperature of water is, for example, 4.5 ° C.

According to the second embodiment, since the increase in the operating frequency of the compressor 10 is prohibited at a temperature at which frosting may start to occur in the evaporator 40, defrosting at room temperature is performed in the evaporator 40, The refrigeration capacity can be restored.

Moreover, in the dehumidifier 1a of this Embodiment 2, after starting frost suppression control, the control part 50 uses the value of humidity H1, temperature T1, humidity H2, and temperature T2, and dehumidification capability Q1 in humidity H1. If the dehumidifying capacity Q1 is smaller than the rated dehumidifying capacity Q2, the rated dehumidifying capacity Q2 is determined based on the model dehumidifying capacity of the dehumidifier 1a, the magnitude of the dehumidifying capacity Q1 and the rated dehumidifying capacity Q2 is compared, Release frosting suppression control and resume normal dehumidification control.

If the operating frequency of the compressor 10 is reduced so that the evaporation temperature does not drop to the freezing temperature of water, the evaporation temperature rises, and the temperature difference between the air and the evaporator 40 becomes smaller, so the dehumidifying ability decreases. In the second embodiment, the control unit 50 compares the decrease in the refrigeration capacity due to frosting and the recovery of the refrigeration capacity due to defrosting, and automatically switches the control so that the dehumidification capacity becomes higher. Therefore, excessive recovery of the refrigerating capacity of the evaporator 40 can be suppressed, and the dehumidification target space can be dehumidified more efficiently.

According to the second embodiment, the control unit 50 adjusts the operating frequency of the compressor 10 to control the evaporation temperature. By controlling the evaporation temperature to be higher than the freezing temperature of water, it is possible to prevent moisture condensed on the evaporator 40 from becoming ice, and to suppress the performance deterioration of the heat exchanger due to frost formation. As a result, the defrosting frequency can be reduced and the dehumidifying ability can be improved.

1, 1a Dehumidifier, 10 Compressor, 15 Piping, 20 Condenser, 30 Expansion Device, 40 Evaporator, 45 Evaporation Temperature Sensor, 50 Control Unit, 51 Memory, 52 CPU, 60 Blower, 61 Airway, 71 Inlet Humidity Sensor, 72 inlet temperature sensor, 81 outlet humidity sensor, 82 outlet temperature sensor.

Claims

A refrigerant circuit in which a compressor, a condenser, an expansion device, and an evaporator are sequentially connected by piping, and the refrigerant circulates;
A blower that circulates air from a dehumidification target space to an air path that returns to the dehumidification target space via the evaporator and the condenser;
An inlet humidity sensor provided at the inlet of the air passage for measuring the humidity of the air;
An evaporation temperature sensor for measuring the evaporation temperature of the evaporator;
A control unit for controlling the compressor, the expansion device and the blower;
Have
The controller is
A dehumidifier that controls an operating frequency of the compressor according to a humidity difference between a target humidity and a measured value of the inlet humidity sensor in a range where the evaporation temperature is higher than a freezing temperature of water.
The controller is
The dehumidifier according to claim 1, wherein an operating frequency of the compressor is increased as a value of the humidity difference is increased.
The controller is
A measurement value is acquired from the inlet humidity sensor at a constant period, a first humidity difference that is a difference between the previously acquired measurement value and the target humidity, and a difference between the currently acquired measurement value and the target humidity. The dehumidifier according to claim 1 or 2, wherein the second humidity difference is compared, and if the second humidity difference is smaller than the first humidity difference, the operating frequency of the compressor is decreased.
The controller is
When the evaporation temperature falls to a predetermined temperature higher than the freezing temperature of water, it is prohibited to increase the operating frequency of the compressor, and frosting suppression control is performed to maintain or decrease the operating frequency. The dehumidifier according to any one of claims 1 to 3.
An inlet temperature sensor that is provided at the inlet of the air passage and measures the temperature of the air;
An outlet humidity sensor provided at the outlet of the air passage for measuring the humidity of the air;
An outlet temperature sensor that is provided at the outlet of the air passage and measures the temperature of the air; and
The controller is
After starting the frosting suppression control, calculate the dehumidifying capacity based on the measured values of the inlet humidity sensor, the inlet temperature sensor, the outlet humidity sensor, and the outlet temperature sensor, and based on the calculated dehumidifying capacity and rated capacity Compared with the rated dehumidifying capacity, if the calculated dehumidifying capacity is smaller than the rated dehumidifying capacity, the frosting suppression control is canceled and the operation according to the humidity difference between the target humidity and the measured value of the inlet humidity sensor The dehumidifier of Claim 4 which restarts control of a frequency.