JP6584342B2 - Dehumidifying and drying equipment - Google Patents

Description

  The present invention relates to a dehumidifying and drying apparatus.

2. Description of the Related Art Conventionally, a dehumidification drying apparatus that performs indoor dehumidification drying in a warehouse such as a food factory or a fishery processing plant, a food storage, or the like is known. There exists patent document 1 as background art of this invention.
In Patent Document 1, “a reserving means for accumulating surplus liquid refrigerant among the refrigerant circulating in the refrigeration cycle is provided, and one of the first and second indoor heat exchangers is operated as a condenser and the other as an evaporator. It is described that the heat dehumidifying operation is possible.

JP 2003-262429 A

  By the way, in patent document 1, when the gas piping and liquid piping which connect an indoor unit and an outdoor unit are long, it is necessary to fill the said refrigerant | coolant amount into the said gas and liquid piping. Moreover, when the refrigerant | coolant amount which does not need additional filling is previously filled into piping which connects a long indoor unit and an outdoor unit beforehand, the efficient operation of an air conditioner cannot be performed. In particular, there is a problem that a sufficient amount of reheat cannot be obtained because the refrigerant becomes excessive in the reheat dehumidifying operation. In addition, there is a problem that the refrigerant amount difference occurs even in the cooling operation, the heating operation, and the reheat dehumidifying operation, and each operation cannot be performed with an appropriate refrigerant amount. Patent Document 1 attempts to solve these problems by storing excess liquid refrigerant in liquid storage means such as a receiver tank.

  However, in the refrigeration cycle of Patent Document 1, the amount of refrigerant in a pipe connecting the indoor unit and the outdoor unit (hereinafter referred to as indoor / outdoor pipe) differs during cooling operation, heating operation, and reheat dehumidification operation. Therefore, the longer the indoor / outdoor pipe length, the more surplus refrigerant during the reheating operation, and the larger the volume required for the liquid storage means. Therefore, there are problems such as an increase in the external shape of the liquid storage means and unit size, an increase in cost, and a limitation on the length of indoor and outdoor piping.

  The present invention has been devised in view of the above circumstances, does not require a liquid storage means, can suppress an increase in unit size and cost, can control an appropriate amount of refrigerant during reheating operation, and obtains a large amount of reheating. An object of the present invention is to provide a dehumidifying and drying apparatus.

In order to solve the above problems, a dehumidifying and drying apparatus according to a first aspect of the present invention includes a compressor that compresses a refrigerant, a condenser that condenses high-pressure refrigerant gas from the compressor, and a high-temperature and high-pressure liquid refrigerant from the condenser. A decompression device for decompressing, an evaporator for evaporating low-temperature and low-pressure refrigerant from the decompression device, a first refrigeration cycle in which they are sequentially connected by refrigerant piping, and the refrigerant piping between the compressor and the condenser A second refrigeration cycle, a blower, and the first and second refrigeration units configured by sequentially connecting the compressor, the third switching device, and the evaporator to the bypass pipe branched through the refrigerant pipe. A control unit that controls the cycle and the blower, a first heat exchanger, a second heat exchanger, an indoor unit that includes the compressor, and an outdoor unit that includes a third heat exchanger. The first heat exchanger is composed of a condenser, a front A reheat dehumidifying operation function for causing the second heat exchanger to function as an evaporator, and a cooling operation function for allowing the third heat exchanger to function as a condenser and the second heat exchanger as an evaporator. comprises a gas pipe and a liquid pipe connecting the outdoor unit and the indoor unit, and the gas pipe between the first switching device and the second opening and closing device provided in each of said liquid pipe, the indoor unit is the decompression A bypass pipe connected to an indoor unit side refrigerant pipe positioned between the third heat exchanger and an opening / closing device provided in the liquid pipe, and bypassing the secondary side of the decompression apparatus, A refrigerant recovery switching device provided in a bypass pipe, and a detecting means for detecting a refrigerant shortage based on a valve opening of the decompression device, a refrigeration cycle piping temperature, or an operating pressure during the reheat dehumidification operation, During the heat dehumidifying operation If it detects a lack of medium, said with opening the refrigerant recovery switchgear, the vacuum less controlled than immediately before opening the valve opening of the device, to collect the refrigerant in the outdoor unit side to the indoor unit side Yes.
A dehumidifying and drying apparatus according to a second aspect of the present invention includes a compressor that compresses a refrigerant, a condenser that condenses high-pressure refrigerant gas from the compressor, a decompressor that decompresses high-temperature and high-pressure liquid refrigerant from the condenser, An evaporator for evaporating the low-temperature and low-pressure refrigerant from the apparatus, a first refrigeration cycle in which the refrigerant is sequentially connected by a refrigerant pipe, and a bypass pipe that branches the refrigerant pipe between the compressor and the condenser The second refrigeration cycle configured by connecting the compressor, the third switching device, and the evaporator, the blower, the first and second refrigeration cycles, and the blower are controlled by the refrigerant pipe. A controller, a first heat exchanger, a second heat exchanger, an indoor unit having a compressor, and an outdoor unit having a third heat exchanger, the first heat exchanger Reheat removal that makes the condenser and the second heat exchanger function as an evaporator It has a function of operation, has a function of cooling operation in which the third heat exchanger functions as a condenser, and the second heat exchanger as an evaporator, and connects the indoor unit and the outdoor unit. A gas pipe and a liquid pipe; and a first opening / closing device provided in the gas pipe in the indoor unit, the indoor unit including the pressure reducing device, and a switching device provided in the third heat exchanger and the liquid pipe; A bypass pipe for bypassing the secondary side of the decompression device from the indoor unit side refrigerant pipe located between the refrigerant pipe and a refrigerant recovery switching device provided in the bypass pipe, and the decompression during the reheat dehumidifying operation Means for detecting excess or deficiency of the refrigerant based on the valve opening of the apparatus, the refrigeration cycle piping temperature, or the operating pressure, and when the refrigerant deficiency is detected during the reheat dehumidifying operation, opens the refrigerant recovery switch And the decompression device Controlling the valve opening degree, the increased amount of refrigerant of the indoor unit of the reheat during dehumidification operation, the case of detecting the refrigerant excess during reheat dehumidification operation, by switching to a fixed time the cooling operation, also the decompression The valve opening of the device is controlled to be smaller than the previous opening, and the refrigerant on the indoor unit side is sent to the outdoor unit side.

  According to the present invention, it is possible to provide a dehumidifying and drying apparatus that does not require a liquid storage means, can suppress an increase in unit size and cost, can be controlled to an appropriate amount of refrigerant during reheating operation, and can obtain a large amount of reheating.

The figure which shows the structural example of the refrigerating cycle of the dehumidification drying apparatus of Embodiment 1 which concerns on this invention. The figure which shows the flow of the refrigerant | coolant at the time of the cooling operation of a dehumidification drying apparatus. The figure which shows the flow of the refrigerant | coolant at the time of the reheat dehumidification driving | operation of a dehumidification drying apparatus. The flowchart at the time of the reheat dehumidification driving | operation start which a dehumidification drying apparatus performs. The cycle figure which shows an example of a refrigerant | coolant collection | recovery means. The block diagram which shows the electrical connection of the controller of a dehumidification drying apparatus. The flowchart of refrigerant | coolant collection | recovery operation | movement. The flowchart of the refrigerant | coolant shortage detection by the operating pressure of the modification 1. The flowchart of the refrigerant | coolant shortage detection by the refrigerating cycle temperature of the modification 2. The figure which shows the refrigeration cycle structural example of the dehumidification drying apparatus of Embodiment 2. FIG. The figure which shows the structural example of the refrigerating cycle of the dehumidification drying apparatus of Embodiment 3. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
The present invention relates to a refrigerant control method for a dehumidifying and drying apparatus J having a separation structure for an indoor unit and an outdoor unit and having a reheat dehumidifying operation function.
The dehumidifying and drying apparatus J is an apparatus that can operate each mode with an appropriate amount of refrigerant without requiring an extra liquid (liquid refrigerant) reservoir.

<< Embodiment 1 >>
FIG. 1 is a diagram illustrating a configuration example of a refrigeration cycle of the dehumidifying and drying apparatus according to the first embodiment of the present invention.
The dehumidifying and drying apparatus J of Embodiment 1 constitutes a refrigeration cycle in which the compressor 3, the outdoor condenser 6, the indoor condenser 4, the decompression apparatus 10, and the indoor evaporator 5 are connected by a refrigerant pipe 30. The decompression device 10 uses an expansion valve in this example.

The refrigerant circulates in the refrigerant pipe 30. The indoor unit 1 and the outdoor unit 2 are installed indoors and outdoors, respectively, and radiate heat from the refrigerant and absorb heat to the refrigerant according to each mode.
The indoor unit 1 performs a cooling operation and a reheat dehumidifying operation.

The indoor unit 1 and the outdoor unit 2 are connected by a gas pipe 12a and a liquid pipe 12b, which are refrigerant pipes that are connected on site according to the respective installation locations. A gaseous refrigerant flows through the gas pipe 12 a and connects the refrigerant pipe 30 downstream of the compressor 3 and the outdoor condenser 6. A liquid refrigerant flows through the liquid pipe 12 b, and connects the outdoor condenser 6 and the refrigerant pipe 30 upstream of the decompression device 10.
In the dehumidifying and drying apparatus J, open / close devices 7 to 9 that open and close the flow of the refrigerant on the refrigeration cycle, for example, electromagnetic valves, are provided.
A cooling operation or a reheat dehumidifying operation can be performed by opening and closing the opening and closing devices 7 to 9 such as electromagnetic valves.

The opening / closing devices 8 and 9 are provided in the gas pipe 12a and the liquid pipe 12b in the indoor unit 1, respectively. By controlling the opening and closing of the opening and closing devices 8 and 9, surplus refrigerant can be stored in the outdoor unit 2 and in the gas pipe 12a and the liquid pipe 12b without liquid storage means such as a receiver. Thereby, the cooling operation and the reheat dehumidifying operation can be performed with an appropriate amount of refrigerant.
Hereinafter, a refrigerant storage method will be described.

<Cooling operation>
First, the cooling operation of the indoor unit 1 that uses the outdoor condenser 6 as a condenser will be described.
FIG. 2 is a diagram illustrating a refrigerant flow during the cooling operation of the dehumidifying and drying apparatus.
In the cooling operation of the indoor unit 1, the liquid refrigerant evaporates in the indoor evaporator 5, thereby cooling the indoor air with latent heat of evaporation. Indoor air is sent to the indoor evaporator 5 by the blower 19 and cooled.

In the cooling operation, the opening / closing device 7 is closed, the opening / closing device 8 is opened, the opening / closing device 9 is opened, and the decompression device 10 is automatically adjusted to an appropriate opening degree. Here, in the refrigeration cycle, for example, R410A is enclosed as a refrigerant, and an amount optimal for the operating state of the cooling operation is enclosed. That is, the optimum amount of refrigerant for the cooling operation according to the length of the gas pipe 12a and the liquid pipe 12b is enclosed.
The refrigerant circulates in the gas pipe 12a, the liquid pipe 12b, and the refrigerant pipe 30 as indicated by arrows in FIG.

<Reheat dehumidification operation>
Next, the operation of the reheat dehumidifying operation using the indoor condenser 4 as the condenser will be described. FIG. 3 is a diagram showing the refrigerant flow during the reheat dehumidifying operation of the dehumidifying and drying apparatus.
In the reheat dehumidifying operation of the indoor unit 1, indoor air passes through the indoor evaporator 5 by the blower 19. In the indoor evaporator 5, the liquid refrigerant evaporates and cools the indoor air to condense it to a temperature below the dew point to obtain low humidity air. Then, low-humidity air is sent to the indoor condenser 4 by the blower 19. The indoor condenser 4 warms the low-humidity air with the heat of condensation when the gas refrigerant is condensed, and is supplied indoors as high-temperature, low-humidity air.

  In the reheat dehumidifying operation, the opening / closing device 7 is opened, the opening / closing device 8 is closed, the opening / closing device 9 is closed, and the decompression device 10 is automatically adjusted to an appropriate opening degree. In the reheat dehumidifying operation, since no refrigerant flows through the outdoor condenser 6, there is no heat radiation from the outdoor unit 2 to the outside, and a large amount of reheat can be obtained.

  Here, since the refrigerant flow path is completed inside the indoor unit 1 in the reheat dehumidifying operation, the necessary amount of refrigerant is constant regardless of the length of the gas pipe 12a and the liquid pipe 12b. This is because both the switchgears 8 and 9 are closed, so that the refrigerant flows through the gas pipe 12 a connecting the outdoor condenser 6 from the switchgear 8 and the liquid pipe 12 connecting the outdoor condenser 6 and the switchgear 9. This is because there is not.

  On the other hand, the longer the length of the gas pipe 12a and the liquid pipe 12b, the larger the refrigerant filling amount. Therefore, the difference between the necessary refrigerant amount during the cooling operation and the necessary refrigerant amount during the reheat dehumidifying operation increases. That is, since the refrigerant in the long gas pipe 12a and the refrigerant in the long liquid pipe 12b are not used in the reheat dehumidification operation, the amount of surplus refrigerant during the reheat dehumidification operation increases.

Therefore, the switching devices 8 and 9 are closed during the reheat dehumidifying operation, and the refrigerant does not flow into the gas pipe 12a from the switching device 8 to the outdoor condenser 6 and from the outdoor condenser 6 to the liquid piping 12b of the switching apparatus 9. Like that. Thereby, the refrigerant | coolant return from the outdoor unit 2 to the indoor unit 1 is prevented.
Note that the opening / closing device 8 and the opening / closing device 9 are not necessarily provided in the indoor unit 1, and may be provided in the gas pipe 12 a and the liquid pipe 12 b outside the outdoor unit 2.

  In addition, as described above, even if only the return of the refrigerant liquid from the outdoor unit 2 is prevented, the reheat dehumidifying operation is started from the state in which the refrigerant is excessively present in the indoor unit 1 from the beginning, such as the indoor low temperature condition. In such a case, there is a concern that the amount of reheat becomes small due to excessive refrigerant or the refrigerant liquid returns to the compressor 3.

  Therefore, in the present dehumidifying and drying apparatus J, as shown in the flowchart at the time of starting the reheat dehumidifying operation in FIG. 4, when starting the reheat dehumidifying operation, the cooling operation is always performed (the solenoid valve 7 is closed and the solenoid valve 8 is opened). The electromagnetic valve 9 is opened) (see FIG. 2), and after a predetermined time elapses, the operation is switched to the reheat dehumidification operation. FIG. 4 is a flowchart at the time of starting the reheat dehumidifying operation executed by the dehumidifying and drying apparatus.

  Thereby, the refrigerant is present in the gas pipe 12a, the liquid pipe 12b, and the outdoor unit 2. Therefore, the reheat dehumidification operation can be started in a state in which the location of the refrigerant in the refrigeration cycle is always constant and the amount of refrigerant in the indoor unit 1 is not excessive.

When the reheat dehumidifying operation is started, the dehumidifying / drying apparatus J is operated as follows.
First, it starts by cooling operation (step S1 of FIG. 4). As shown in FIG. 2, the opening / closing device 7 is closed and activated by a cooling operation in which the opening / closing devices 8, 9 are opened.

Subsequently, it is determined whether or not a predetermined time has elapsed for the refrigerant to reach a steady state in the cooling operation (step S2 in FIG. 4). The predetermined time for the steady state is set in advance.
Note that the determination of switching to the reheat dehumidifying operation in step S2 “Due to predetermined time?” Is not necessarily a determination of whether or not the predetermined time has elapsed, but a refrigeration cycle indicating that the cooling operation has reached a steady state. The temperature or pressure may be used. For example, you may carry out by the temperature of the entrance side or exit side of the indoor evaporator 5, the suction pressure of the compressor 3, etc.

If the predetermined time has not elapsed (No in step S2), step S2 is continued, and the determination of whether or not the predetermined time has elapsed is continued.
When the predetermined time has elapsed (Yes in step S2), as shown in FIG. 3, the switchgear 7 is opened and the switchgears 8 and 9 are switched to the reheat dehumidifying operation (step S3), and the start-up operation is terminated.
As described above, when the reheat dehumidifying operation is started, there is a possibility that the amount of refrigerant inside the indoor unit 1 may be insufficient, so the following refrigerant collecting means for collecting a necessary amount of refrigerant from the outdoor unit 2 is provided. ing.

<Refrigerant recovery means>
FIG. 5 is a cycle diagram showing an example of the refrigerant recovery means.
A bypass pipe 30p that connects the secondary side (exit side) position of the liquid pipe 12b and the secondary side (exit side) of the decompression device 10 is provided. An opening / closing device (for example, an electromagnetic valve) 13 for collecting the refrigerant is provided on the bypass pipe 30p. A refrigerant recovery method using the bypass pipe 30p and the opening / closing device 13 will be described below.

FIG. 6 is a block diagram showing the electrical connection of the controller of the dehumidifying and drying apparatus.
The dehumidifying and drying apparatus J is provided with a controller 101 and various sensors.
The controller 101 is composed of a microcomputer, peripheral circuits, and the like. The controller 101 is a control device that centrally controls the entire dehumidifying and drying device J such as control of the opening / closing devices 7, 8, 9, 13 and the decompression device 10.
The controller 101 includes a decompression device control unit 102, a refrigerant shortage determination unit 103, and a refrigerant recovery control unit 104 for refrigerant recovery.

<Refrigerant recovery operation>
FIG. 7 is a flowchart of the refrigerant recovery operation.
In the dehumidifying and drying apparatus J, the opening degree of the decompression apparatus 10 is controlled so that the refrigerant superheat degree at the outlet (secondary side) of the indoor evaporator 5 becomes a preset target value, for example. Therefore, in a state where the amount of refrigerant during operation is insufficient, the amount of refrigerant circulation in the refrigeration cycle decreases, and the degree of refrigerant superheat at the outlet of the indoor evaporator 5 increases.

Therefore, in order to bring the refrigerant superheat degree close to the target value, the decompression device controller 102 controls the decompression device 10 in the opening direction, and is stabilized at a large opening as compared with an appropriate amount of refrigerant.
Therefore, the refrigerant shortage determination unit 103 determines whether or not the refrigerant is insufficient by determining whether or not the opening of the decompression device 10 is larger than a predetermined opening, as shown in S11 of FIG. . The predetermined opening is a set value of the opening of the decompression device 10 obtained in advance for determining the refrigerant shortage.
Note that the refrigerant shortage determination does not necessarily use the opening of the decompression device (10), and can be replaced with the operating pressure, the operating pressure and the ambient air temperature, the operating pressure and the refrigeration cycle temperature, and the like.

When the opening degree of the decompression device 10 is equal to or less than the predetermined opening degree (No in S11 of FIG. 7), the process proceeds to S11, and the monitoring of the opening degree of the decompression device 10 is continued.
When it is determined that the opening of the decompression device 10 is larger than the predetermined opening and the refrigerant is insufficient (Yes in S11), the process proceeds to step S12, and the pressure 2p (see FIG. 5) of the outdoor unit 2 is the low pressure of the indoor unit 1. It is determined whether or not it is greater than 1p (see FIG. 5), and a refrigerant recovery method is determined.

  When the pressure 2p of the outdoor unit 2> the low pressure 1p of the indoor unit 1, the bypass pipe 30p is opened by opening the switching device 13 due to a pressure difference between the pressure 2p of the outdoor unit 2 and the low pressure 1p of the indoor unit 1. Thus, the refrigerant can be collected from the outdoor unit 2 to the indoor unit 1.

  The refrigerant recovery means shown in FIG. 5 is a method of recovering the refrigerant from the outdoor unit 2 to the indoor unit 1 due to the pressure difference between the secondary side of the liquid pipe 12b and the secondary side of the decompression device 10. Therefore, when the secondary side pressure of the liquid pipe 12b> the secondary side pressure of the pressure reducing device 10 (Yes in S12), the refrigerant can be recovered. For example, under specific conditions of outdoor low temperature and indoor high temperature such as a food processing plant in winter, the secondary pressure of the liquid pipe 12b ≦ the secondary pressure of the decompression device 10 (No in S12), and the refrigerant recovery shown in FIG. The means cannot recover the refrigerant. Therefore, the process proceeds to S14 in FIG. 7, and the opening of the decompression device 10 is opened to a predetermined opening larger than the normal opening in order to return the refrigerant and switched to the cooling operation (see FIG. 2) (S14 in FIG. 7). ). By making the cooling operation and increasing the opening of the decompression device 10, the refrigerant on the outdoor unit 2 side can be effectively recovered on the indoor unit 1 side as shown in FIG.

Note that the determination in S12 of FIG. 7 is not necessarily a method of directly comparing the pressures described above. For example, a comparison between the piping temperature of the outdoor unit 2 and the piping temperature 30t on the secondary side of the indoor evaporator 5 (see FIG. 5). It can also be performed by comparing the outdoor air temperature and the secondary pipe temperature 30t of the indoor evaporator 5 or the like.
After the start of refrigerant recovery, as shown in S15 of FIG. 7, whether or not the opening of the decompression device 10 is in an appropriate range that is larger than the lower limit predetermined opening indicating that the amount of the refrigerant is appropriate and smaller than the upper predetermined opening. (S15 in FIG. 7).

When the amount of the refrigerant is not within the appropriate range (No in S15), the process proceeds to step S15 and monitoring is performed until the amount of the refrigerant becomes appropriate.
On the other hand, when the amount of the refrigerant is within the appropriate range (Yes in S15), the refrigerant recovery in steps S13 and S14 is terminated.

Note that the determination of the end of refrigerant recovery is not necessarily performed based on the opening of the decompression device 10, and can be replaced with a predetermined time, an operating pressure, a refrigeration cycle temperature, or the like obtained in advance.
The predetermined time is obtained in advance as a predetermined time during which the refrigerant can be collected, and it is determined whether or not the refrigerant has been collected depending on whether or not the predetermined time has elapsed.
With the operating pressure, an operating pressure range in which the amount of refrigerant is appropriate is obtained in advance, and it is determined whether or not the recovery of the refrigerant has been completed based on whether or not the actual operating pressure is within the operating pressure range.

The refrigeration cycle temperature is obtained in advance as to the temperature range of the refrigeration cycle in which the amount of refrigerant is appropriate, and whether or not the refrigerant recovery is completed depending on whether or not the actual refrigeration cycle temperature is within the temperature range of the refrigeration cycle. judge.
By performing a series of these operations, it is possible to appropriately adjust the amount of refrigerant on the indoor unit 1 side during the reheat dehumidifying operation.

  According to the above configuration, the refrigerant shortage during the reheat dehumidification operation is provided by providing the decompression device control unit 102, the refrigerant shortage determination unit 103, and the refrigerant recovery control unit 104 as detection means for detecting the refrigerant shortage during the reheat dehumidification operation. Can be detected.

  Moreover, by always starting the dehumidification drying apparatus J by cooling operation, a refrigerant | coolant can be efficiently stored in the outdoor unit 2 and the outdoor unit connection piping (12a, 12b) at the time of reheat dehumidification operation. In addition, the cooling operation can be performed quickly.

  Further, by closing the solenoid valves 8 and 9 during the reheat dehumidifying operation, excess refrigerant generated during the reheat dehumidifying operation can be stored in the outdoor unit 2 side.

  Further, if the opening / closing devices 8 and 9 are provided in at least one of the gas pipe 12a and the liquid pipe 12b in the indoor unit 1, the refrigerant stored in the outdoor unit 2 and the indoor / outdoor unit connection pipes (12a and 12b). The amount of can be increased. In particular, the amount of refrigerant stored can be increased when at least one of the gas pipe 12a and the liquid pipe 12b is long.

  Further, by providing a bypass pipe 30p that connects the position of the secondary side of the liquid pipe 12b and the secondary side of the decompression device 10, and by providing the refrigerant recovery switchgear 13 on the bypass pipe 30p, reheat dehumidification When there is little refrigerant in the indoor unit 1 during operation, it can be recovered from the outdoor unit 2.

  Further, the opening / closing devices 8 and 9 are provided in the gas pipe 12a and the liquid pipe 12b, respectively, and the outdoor unit 2 side is closed, so that surplus refrigerant can be removed from the outdoor unit 2 and Store in the indoor / outdoor unit connection piping (12a, 12b). Accordingly, it is possible to provide a dehumidifying and drying apparatus J that can suppress the increase in unit size and cost, appropriately control the amount of refrigerant in the refrigeration cycle during reheat dehumidification operation, and obtain a large amount of reheat.

<Modification 1>
FIG. 8 is a flowchart of the refrigerant shortage detection by the operation pressure according to the first modification.
Modification 1 is an example (S21 in FIG. 8) in which the refrigerant shortage detection (S11 in FIG. 7) is performed with the operating pressure during the reheat dehumidification operation.
In the dehumidifying and drying apparatus J, the case where the refrigerant shortage is determined based on the operating pressure of the first modification will be described.
For example, as shown in FIG. 5, a pressure sensor sp that can detect the refrigerant pressure is provided between the compressor 3 and the indoor condenser 4. Then, the refrigerant pressure in the high-pressure gas state discharged from the compressor 3 is detected.

  The high-pressure gas refrigerant pressure during the reheat dehumidification operation is determined by the refrigerant filling amount, the suction air wet bulb temperature, the compressor rotation speed, and the air volume passing through the indoor condenser 4. Therefore, the determination pressure for determining the refrigerant shortage based on all or a part of these is determined in advance. The determination pressure is a pressure determined based on the operating pressure when the normal refrigerant is charged, a characteristic equation using the intake air wet bulb temperature, the compressor rotational speed, and the air volume passing through the indoor condenser 4 as a variable, a pressure table Etc. are set in advance.

  In a state where the amount of refrigerant during operation is insufficient, the amount of refrigerant circulating in the refrigeration cycle decreases, so the operating pressure is lower than the determination pressure. Therefore, the refrigerant shortage determination unit 103 (see FIG. 6) compares the discharge refrigerant pressure from the compressor 3 with the determination pressure as shown in step S21 of FIG. In S21 of FIG. 8, it is determined that the refrigerant is insufficient. In addition, when it is not discharge refrigerant | coolant pressure> determination pressure (it is No at S21 of FIG. 8), monitoring by step S21 is continued.

In the same manner, for example, the refrigerant shortage can be determined even with the refrigerant pressure on the suction side of the compressor 3.
According to Modification 1, it is possible to determine whether or not the refrigerant in the reheat dehumidifying operation is insufficient by detecting the refrigerant pressure discharged from the compressor 3.

<Modification 2>
Modification 2 is an example in which detection of refrigerant shortage (S11 in FIG. 7) is performed at the temperature of the refrigeration cycle.
FIG. 9 is a flowchart of refrigerant shortage detection based on the refrigeration cycle temperature according to the second modification.
In the dehumidifying and drying apparatus J, a case where the refrigerant shortage is determined based on the temperature of the refrigeration cycle of the second modification will be described.

  For example, as shown in FIG. 5, a temperature sensor st that can detect the discharged refrigerant temperature is provided between the compressor 3 and the indoor condenser 4. Then, the refrigerant temperature in the high-pressure gas state discharged from the compressor 3 is detected.

  In the dehumidifying and drying apparatus J, the opening degree of the decompression apparatus 10 is controlled such that the refrigerant superheat degree at the outlet 3t of the compressor 3 becomes a preset target value, for example. In a state where the amount of refrigerant during operation is insufficient, the pressure in the refrigeration cycle is low. Therefore, when the refrigerant superheat degree is brought close to the target value, the discharge refrigerant temperature decreases due to the physical properties of the refrigerant.

Therefore, the determination temperature is set in advance based on the discharge refrigerant temperature at the normal refrigerant charging amount. Then, as shown in S31 of FIG. 9, the refrigerant shortage determination unit 103 (see FIG. 6) determines the refrigerant shortage by comparing the discharge refrigerant temperature with the determination temperature (S31 of FIG. 9).
When the discharge refrigerant temperature <the determination temperature (Yes in S31 of FIG. 9), it is determined that the refrigerant is insufficient. If the discharge refrigerant temperature <the determination temperature is not satisfied (No in S31 of FIG. 9), the monitoring in Step S31 is continued.

  According to the second modification, it is possible to determine whether or not the refrigerant in the reheat dehumidifying operation is insufficient by detecting the temperature of the refrigerant discharged from the compressor 3.

<< Embodiment 2 >>
FIG. 10 is a diagram illustrating a configuration example of the refrigeration cycle of the dehumidifying and drying apparatus according to the second embodiment.
In the first embodiment, the configuration of the refrigeration cycle in which the cooling operation and the reheat dehumidification operation are switched by the opening / closing devices 7, 8, and 9 has been described.
In the second embodiment, an example of the refrigerant storage method of the refrigeration cycle in which the cooling operation and the reheat dehumidification operation are switched by the refrigerant switching means (for example, a four-way valve) 20 will be described.
Since the other configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the cooling operation, the four-way valve 20 is connected as shown by the broken line in FIG. 10, the closing device 8 is opened, the closing device 9 is opened, and the decompression device 10 is automatically adjusted to an appropriate opening degree to realize the cooling operation. ing. Similar to the first embodiment, the refrigerant is sealed in the refrigeration cycle in an amount that optimizes the operation state of the cooling operation. In FIG. 10, the flow of the refrigerant during the cooling operation is indicated by a two-dot chain line.

  In the reheat dehumidifying operation, the four-way valve 20 is connected as indicated by a solid line, and the pressure reducing device 10 is automatically adjusted to an appropriate opening degree. At this time, the closing device 8 is closed to close the gas pipe 12a, and the closing device 9 is closed to close the liquid pipe 12b. As a result, as in the first embodiment, refrigerant return from the outdoor unit 2 to the indoor unit 1 is prevented, and excess refrigerant is stored in the outdoor unit 2 and the gas pipe 12a and the liquid pipe 12b that have flowed in the cooling operation or the like. can do. In FIG. 10, the flow of the refrigerant during the reheat dehumidification operation is indicated by a broken line.

  Further, the refrigerant recovery performed when the indoor unit 1 is short of the refrigerant does not need to be provided with a dedicated refrigerant recovery circuit as in the first embodiment. By opening the closing device 8 during the reheat dehumidifying operation, the outdoor unit 2 and the decompression device 10 secondary side (exit side) are connected. Therefore, when the outdoor unit 2 pressure> the pressure reducing device 10 secondary side (outside) pressure, the refrigerant can be recovered using the pressure difference.

  When the outdoor unit 2 pressure ≦ the pressure reducing device 10 secondary side (exit side) pressure, the opening degree of the pressure reducing device 10 is set to a predetermined opening degree larger than the normal opening degree as in the first embodiment, and is switched to the cooling operation. Then, the refrigerant in the indoor unit 1 is allowed to flow to the outdoor unit 2 (see FIG. 2), and the refrigerant can be recovered.

As mentioned above, the surplus refrigerant | coolant at the time of a reheat dehumidification driving | operation can be stored by the outdoor unit 2 side by providing the obstruction | occlusion apparatus 8 in the gas piping 12a.
By closing the closing device 8 during the reheat dehumidifying operation, surplus refrigerant generated during the reheat dehumidifying operation can be stored in the outdoor unit 2 side.

  Therefore, it is possible to store surplus refrigerant in the outdoor unit 2 and the indoor / outdoor connection pipes (gas pipe 12a, liquid pipe 12b) without requiring a means dedicated to liquid storage such as a receiver tank. Thereby, an increase in the size of the unit and an increase in cost can be suppressed, and an effective operation can be performed by appropriately controlling the amount of refrigerant in the refrigeration cycle during the reheating operation. Therefore, it is possible to provide a dehumidifying and drying apparatus 2J that can obtain a large amount of reheat.

<< Embodiment 3 >>
FIG. 11 is a diagram illustrating a configuration example of a refrigeration cycle of the dehumidifying and drying apparatus according to the third embodiment.
The dehumidifying and drying apparatus 3J according to the third embodiment has a configuration in which the opening / closing device 9 is deleted from the dehumidifying and drying apparatus 3J according to the first embodiment illustrated in FIG.
Since the other configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

In the refrigerating cycle of the dehumidifying and drying apparatus 3J, during the reheat dehumidifying operation, when the refrigerant pressure of the check valve 11a part> the refrigerant pressure of the check valve 11b part, the refrigerant does not flow from the outdoor unit 2 to the indoor unit 1, Excess refrigerant can be stored in the outdoor unit 2.
Further, under some conditions where the refrigerant pressure at the check valve 11a portion is equal to or lower than the refrigerant pressure at the check valve 11b portion, such as the outdoor high temperature and the indoor low temperature, the refrigerant gradually flows from the outdoor unit 2 to the indoor unit 1 due to the pressure difference. Move. Therefore, it is possible to move the refrigerant to the outdoor unit 2 again by restricting the decompression device 10 to a predetermined opening at regular intervals and switching to the cooling operation.

  By repeating this, excess refrigerant can be stored in the outdoor unit and the indoor / outdoor connection pipe (gas pipe 12a, liquid pipe 12b) without requiring a dedicated means such as a receiver tank.

The compressor 3 is always started in a state (cooling operation) in which the opening / closing device 8 provided in the gas pipe 12a is opened.
Thereby, an increase in the size of the unit and an increase in cost can be suppressed, and an effective operation can be performed by appropriately controlling the amount of refrigerant in the refrigeration cycle during the reheating operation. Therefore, it is possible to provide the dehumidifying and drying apparatus 3J that can obtain a large amount of reheat.

<< Other Embodiments >>
1. In the first embodiment and the like, various configurations have been described, but the configurations may be appropriately combined.

2. The configuration described in the first embodiment and the like shows an example of the present invention, and various specific forms and modifications are possible within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 3 Compressor 4 Indoor condenser (condenser, 1st heat exchanger)
5 Indoor evaporator (evaporator, second heat exchanger)
6 Outdoor condenser (third heat exchanger)
7 Switchgear (third switchgear)
8 Switchgear (first switchgear)
9 Switchgear (second switchgear)
10 Pressure reducing device 12a Indoor / outdoor connecting gas piping (gas piping)
12b Indoor / outdoor connection liquid piping (liquid piping)
13 Opening and closing device (Opening and closing device for refrigerant recovery)
19 Blower 30 Refrigerant piping 30p Bypass pipe 101 Controller (control part)
102 Pressure reducing device controller (detection means)
103 Refrigerant shortage determination unit (detection means)
104 Refrigerant recovery control unit (detection means)
J, 2J, 3J Dehumidification dryer

Claims (2)

A compressor that compresses the refrigerant; a condenser that condenses the high-pressure refrigerant gas from the compressor; a decompressor that depressurizes the high-temperature and high-pressure liquid refrigerant from the condenser; and an evaporation that evaporates the low-temperature and low-pressure refrigerant from the decompressor And a first refrigeration cycle in which they are sequentially connected by refrigerant piping,
A second refrigeration cycle configured by connecting the compressor, the third switching device, and the evaporator with a bypass pipe that branches the refrigerant pipe between the compressor and the condenser through the refrigerant pipe; ,
A blower,
A controller that controls the first and second refrigeration cycles and the blower;
A first heat exchanger, a second heat exchanger, an indoor unit including the compressor, and an outdoor unit including a third heat exchanger,
A function of reheat dehumidification operation in which the first heat exchanger functions as a condenser and the second heat exchanger functions as an evaporator;
The third heat exchanger has a function of cooling operation that functions as a condenser and the second heat exchanger as an evaporator,
A gas pipe and a liquid pipe connecting the indoor unit and the outdoor unit;
A first switching device and a second switching device provided in each of the gas piping and the liquid piping ;
The indoor unit includes the decompression device,
A bypass pipe connected to an indoor unit side refrigerant pipe positioned between the third heat exchanger and an opening / closing device provided in the liquid pipe, and bypassing the secondary side of the decompression device;
A refrigerant recovery switchgear provided in the bypass pipe;
Detecting means for detecting a shortage of refrigerant by the valve opening of the pressure reducing device during the reheat dehumidifying operation, the refrigeration cycle piping temperature, or the operating pressure;
When the shortage of the refrigerant during the reheat dehumidifying operation is detected, the refrigerant recovery switching device is opened, the valve opening of the decompression device is controlled to be smaller than the previous opening, and the refrigerant on the outdoor unit side is A dehumidifying and drying apparatus that collects the indoor unit. A compressor that compresses the refrigerant; a condenser that condenses the high-pressure refrigerant gas from the compressor; a decompressor that depressurizes the high-temperature and high-pressure liquid refrigerant from the condenser; and an evaporation that evaporates the low-temperature and low-pressure refrigerant from the decompressor And a first refrigeration cycle in which they are sequentially connected by refrigerant piping,
A second refrigeration cycle configured by connecting the compressor, the third switching device, and the evaporator with a bypass pipe that branches the refrigerant pipe between the compressor and the condenser through the refrigerant pipe; ,
A blower,
A controller that controls the first and second refrigeration cycles and the blower;
A first heat exchanger, a second heat exchanger, an indoor unit having a compressor,
An outdoor unit including a third heat exchanger,
The first heat exchanger functions as a condenser, and the second heat exchanger functions as an evaporator.
The third heat exchanger has a function of a cooling operation that functions as a condenser and the second heat exchanger as an evaporator,
A gas pipe and a liquid pipe connecting the indoor unit and the outdoor unit;
A first opening / closing device provided in a gas pipe in the indoor unit ;
The indoor unit includes the decompression device,
A bypass pipe that bypasses the secondary side of the decompression device from the indoor unit side refrigerant pipe located between the third heat exchanger and the switch provided in the liquid pipe;
A refrigerant recovery switch provided in the bypass pipe,
Means for detecting the excess or shortage of refrigerant by the valve opening of the decompression device during the reheat dehumidification operation, or the refrigeration cycle piping temperature, or the operation pressure;
When a shortage of refrigerant is detected during the reheat dehumidifying operation, the refrigerant recovery switch is opened and the valve opening of the decompression device is controlled to determine the refrigerant amount of the indoor unit during the reheat dehumidifying operation. Increase,
When excessive refrigerant is detected during the reheat dehumidifying operation, the operation is switched to the cooling operation for a certain time, and the valve opening of the pressure reducing device is controlled to be smaller than the previous opening, and the refrigerant on the indoor unit side is discharged to the outdoor unit. A dehumidifying and drying apparatus characterized by being sent to the machine side .

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