JPH0649127B2 - Low dew point dehumidifier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a low dew point dehumidifying device, and particularly to cooling gas such as air and various gases, and freezing or frosting the moisture in the gas (hereinafter,
The present invention relates to a low dew point dehumidifying device that dehumidifies by simply making it frost.

[Prior art]

Conventionally, as one of the devices for dehumidifying the moisture contained in the gas to a dew point below the freezing point, a frost-dehumidification system device for frosting and removing the moisture in the gas is disclosed in, for example, JP-A-54-54. 6
It is already known from Japanese Patent No. 3540.

In such a dehumidifier, as shown in FIG. 3, the gas to be dehumidified enters one heat exchanger 32 through the four-way switching valve 31 and ice or frost attached to the heat transfer pipe 32a. It is pre-cooled to a dew point around 0 ° C. by exchanging heat with (hereinafter, simply referred to as frost), then enters the other heat exchanger 34 through the communication passage 33, and the refrigerant below the target dew point is supplied. The heat transfer tube 34a is cooled to remove the moisture in the gas by frosting the surface of the heat transfer tube 34a, and the dehumidified gas is sent out through the four-way switching valve 31. There is. Further, in the one heat exchanger 32, the frost adhering to the surface of the heat transfer tube 32a is melted by the heat of the gas and drops into the water reservoir 32b in the lower part of the heat exchanger so as to be discharged to the outside. Made of
The refrigerant is supplied to the heat transfer tube 32a or 34a to be frosted via the electromagnetic valves 35 and 36.

In this way, defrosting of the surface of the heat transfer tube 32a of the one heat exchanger 32 is completed, and the heat transfer tube 34a of the other heat exchanger 34 is completed.
When the amount of frost on the surface of the sheet increases, the four-way switching valve 31 and the solenoid valves 35 and 36 are switched, so that the above steps are performed in heat exchangers opposite to each other, and the defrost precooling step and the frost-dehumidification step And are alternately performed in the pair of heat exchangers 32 and 34. The heat of condensation in the refrigerator that supplies the refrigerant is discharged to the outside of the system by cooling water.

However, in the above configuration, since gas is used to dissolve frost, when the temperature of the incoming gas is low, the temperature difference between the adhered frost and the gas is small, and as a result, the removal is eliminated. The frost ability is small, and it takes time to defrost, and during that time, a large amount of frost adheres to the frosting side heat exchanger, resulting in a poor dehumidifying effect. Such a phenomenon is particularly remarkable in cold regions. Moreover, since the gas passes through a pair of heat exchangers connected in series, there is a problem that the pressure loss is large.

On the other hand, in order not to cause the above problems due to the use of gas, Japanese Utility Model Publication No. 53-105551 has two main air coolers, which are evaporators of a refrigerator, and these main air coolers are provided. A device for directly supplying the refrigerant of the refrigerator and performing dehumidification accompanied by frost formation by one of the main air coolers and performing defrosting by the other main air cooler as in the above example is disclosed. .

That is, in this device, by switching the connection between the air inlets and outlets of both main air coolers and the heat transfer tubes for cooling circulation, both main air coolers can be operated in parallel so that one main air cooler can always be operated. In addition to being disposed, the one main air cooler is switchably connected to the heat transfer tubes in the other main air cooler so that the high temperature refrigerant from the refrigerant compressor can be sent to the heat transfer tubes.

However, in the above configuration, since the refrigerant of the refrigerator is directly supplied and the heat of condensation is used as it is, the refrigeration cycle of the refrigerator is directly affected and the operation tends to be unstable. Therefore, liquid return of the refrigerant may occur, and this liquid return causes liquid compression in the compressor, which may damage the compressor. Further, a heat exchanger for pre-cooling and reheating is provided in the preceding stage of the both main air coolers, and the air for dehumidification treatment is
Since it passes through each heat exchanger, there is a problem that the pressure loss becomes large.

[Object of the Invention]

The present invention has been made in consideration of the above conventional problems, and an object of the present invention is to provide a low dew point dehumidifying device that has a high defrosting capability and can perform stable operation, and has high reliability. I am trying.

[Structure of Invention]

A low dew point dehumidifier according to a first aspect of the present invention includes a pair of heat exchangers that can alternately supply a gas to be dehumidified, and cools these heat exchangers to frost the moisture in the gas for dehumidification. And a cooling brine circulation line for selectively supplying the cold brine cooled by the evaporator of the refrigerator to the heat exchanger to which the gas is supplied, and the condenser of the refrigerator. The hot brine circulation line, which is a circulation line different from the above-mentioned cold brine circulation line, is provided for supplying the hot brine heated in (1) to the heat exchanger to which the gas is not supplied. In addition, the hot brine here is
It also includes hot water heated by the heat of condensation.

In this way, by performing defrosting by using the warm brine due to the heat of condensation of the refrigerator, both the heat capacity and the heat transfer efficiency are superior as compared with defrosting by a gas having a low temperature and a small temperature difference from frost formation. Therefore, the frost can be quickly and surely melted. In addition, since the hot brine is used, the refrigeration cycle is directly affected and the operation becomes unstable and liquid returns of the refrigerant as in the case of directly supplying the refrigerant of the refrigerator and using the heat of condensation as it is. Such a situation can be avoided. Further, since the gas only passes through one heat exchanger, the pressure loss will be small.

The low dew point dehumidifying device according to the second aspect of the invention is, in addition to the above configuration, provided with a cold brine branch line capable of supplying cold brine to a heat exchanger to which gas is not supplied, and supplying the hot brine. It is characterized in that a bypass line for bypassing the heat exchanger is provided in the line.

As a result, after defrosting is completed in the heat exchanger on the defrosting side, the hot brine can be bypassed before the gas is supplied, the supply thereof can be stopped, and the cold brine can be precooled by supplying the cold brine. Therefore, dehumidification at the time of switching can be surely performed.

Example 1 An example of the present invention will be described below with reference to FIG. First
The second heat exchangers 1 and 2 are arranged side by side, and the gas inlet pipes 3 are selectively connectable to the gas inlets 1a and 2a thereof via the three-way switching valve 4. The gas outlets 1b, 2b of each heat exchanger 1, 2 are connected to the gas outlet pipe 5. In addition, a heat medium inlet 1c communicating with the heat transfer tubes of the heat exchangers 1 and 2,
2 c is connected to two ports of the inlet four-way switching valve 6, and the heat medium outlets 1 d and 2 d are connected to two ports of the outlet four-way switching valve 7. The remaining two ports of the inlet four-way switching valve 6 are provided with a cold brine circulation line 8 from the refrigerator 10.
Is connected to the supply side line 8a of the hot brine circulation line 9 from the refrigerator 10. A discharge side line 8b of the cold brine circulation line 8 and a discharge side line 9b of the warm brine circulation line 9 are connected to the remaining two ports of the outlet four-way switching valve 7. In this way, by switching the both four-way switching valves 6 and 7, cold brine and hot brine can be alternately supplied to the first and second heat exchangers 1 and 2, respectively.

The refrigerator 10 includes a compressor 11 such as a screw compressor driven by a motor, a condenser 12, an expansion valve 13, and an evaporator 14, and these devices are used as a refrigerant (for example, R22).
Etc.) is designed to circulate. Further, in the condenser 12, the warm brine is heated to, for example, 3 by the heat of condensation of the refrigerant.
The evaporator is configured to be heated to about 0 ° C., and the evaporator 14 is configured to cool the cold brine to about −25 ° C. by the heat of evaporation of the refrigerant. The cold brine is pumped from a cold brine tank 16 installed in the cold brine circulation line 8 to a pump 15
It is pressure-fed and is returned to the cold brine tank 16 for circulation. Further, the warm brine is pumped from the warm brine tank 18 arranged in the warm brine circulation line 9 by the pump 17, and returned to the warm brine rank 18 via the spare cooler 19 to be circulated.

In the above structure, the cold brine discharged from the evaporator 14 is sent to the first heat exchanger 1 through the cold brine circulation line 8, and the gas containing water is supplied from the gas inlet pipe 3 through the three-way switching portion 4 to the first heat exchanger 1. When sent to the heat exchanger 1, the gas exchanges heat with cold brine to be cooled, and the moisture in the gas frosts the heat transfer tube surface inside the heat exchanger 1 to dehumidify the gas. The gas having a low dew point of about −15 ° C. is delivered from the gas outlet pipe 5. On the other hand, to the second heat exchanger 2, the hot brine discharged from the condenser 12 is circulated and supplied through the hot brine circulation line 9, and heat is exchanged with the frost adhering to the surface of the heat transfer tube to perform defrosting. The dissolved water is discharged out of the system by the drain trap 42.

After a lapse of time, when the frost is sufficiently adhered to the first heat exchanger 1 and the defrosting of the second heat exchanger 2 is completed, the three-way switching valve 4 is switched to change the gas to the second heat exchange. The first heat exchanger 1 defrosts the gas and the first heat exchanger 2 dehumidifies the gas. By repeating the above operation, it is possible to continuously dehumidify the gas. The cooler 19 is used when the amount of heat of condensation of the refrigerator 10 cannot be covered by defrosting. Also, the brine tanks 16 and 18
The pipe 43 for connecting the gaps makes the nonuniformity of the return amount of the cold / warm brine to the brine tank caused by the switching of the cold / warm brine uniform by overflow.

Second Embodiment Another embodiment of the present invention will be described with reference to FIG. In the heat exchanger in which the defrosting process is completed in the first embodiment, when the gas is switched so as to start the frost formation process immediately after that, the temperature of the heat exchanger is rising, and the cold brine is cooled. It will not be possible to dehumidify by frost formation until it is sufficiently cooled by the supply of. Therefore, in this embodiment, in one heat exchanger, after the defrosting process is completed,
The hot brine is bypassed, and cold brine is supplied to enable precooling.

The basic configuration of this embodiment is similar to that of the first embodiment,
Constituent members having the same function are designated by the same reference numerals, and the description thereof will be omitted. Branch lines 21a, 21b from the middle of the supply line 8a of the cold brine circulation line 8 to the inlet side
Is branched and connected to the heat medium inlets 1c and 2c of the first and second heat exchangers 1 and 2 via electromagnetic valves 22a and 22b, respectively. Similarly, the outlet side branch line 21c, 21d is branched from the middle of the discharge side line 8b, and electromagnetic valves 22c, 22d are respectively provided at the heat medium outlets 1d, 2d of the first and second heat exchangers 1, 2. Connected through. Further, the supply side line 9a and the discharge side line 9b of the warm brine circulation line 9 are connected by a bypass line 23, and solenoid valves 24a, 24b, 24 arranged in these lines are connected.
The hot brine can be bypassed at c without passing through the heat exchangers 1 and 2.

In addition, when pre-cooling the heat exchanger 1, the bypass line 2
3 solenoid valve 24a is opened, and solenoid valves 24b and 24
c may be closed and the solenoid valves 22a and 22c of the branch lines 21a and 21c may be opened. When precooling the heat exchanger 2, the solenoid valve 24 of the bypass line 23 is opened,
Solenoid valves 24b and 24c are closed, branch lines 21b and 21
The solenoid valves 22b and 22d of d may be opened.

〔The invention's effect〕

As described above, the low dew point dehumidifier of the first aspect of the present invention has a pair of heat exchangers that can alternately supply the gas to be dehumidified,
A refrigerator for cooling these heat exchangers to frost the moisture in the gas to dehumidify is provided, and the cold brine cooled by the evaporator of this refrigerator is selectively supplied to the heat exchanger to which the gas is supplied. And a cold brine circulation line for supplying the hot brine heated by the condenser of the refrigerator to a heat exchanger to which no gas is supplied, which is a circulation line different from the cold brine circulation line. This is a configuration in which a warm brine circulation line is provided.

As a result, the defrosting of the heat exchanger is performed by the hot brine that uses the condensation heat of the refrigerator that has been discharged to the outside by the cooling water, etc., so defrosting can be performed without the need for a separate heat source. it can. Moreover, since the heat capacity and the heat transfer efficiency are both excellent as compared with defrosting with a gas having a low temperature and a small temperature difference from frost formation, the frost can be quickly and reliably melted. In addition, since the hot brine is used, the refrigeration cycle is directly affected and the operation becomes unstable and liquid returns of the refrigerant as in the case of directly supplying the refrigerant of the refrigerator and using the heat of condensation as it is. Such a situation can be surely avoided. In addition, since the gas only passes through one heat exchanger, the pressure loss can be reduced.

Further, the low dew point dehumidifying device according to the second invention is, as described above,
In addition to the configuration of the first invention, a configuration is provided in which a heat exchanger to which gas is not supplied is provided with a branch line capable of supplying the cold brine, and a hot brine supply line is provided with a bypass line that bypasses the heat exchanger. Is.

As a result, in addition to the effect of the first aspect of the present invention, it is possible to further precool the defrosting-side heat exchanger after defrosting is completed, and to perform dehumidification during switching while continuously flowing gas. The effect is that it can be reliably performed.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention, FIG. 2 is a structural explanatory view showing another embodiment of the present invention, and FIG. 3 is a structural explanatory view of a conventional example. 1 and 2 are heat exchangers, 8 is a cold brine circulation line, 9 is a warm brine circulation line, 10 is a refrigerator, and 21a and 21b.
21c and 21d are branch lines and 23 is a bypass line.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiori Ohama 2-6-1 Nakajima, Takasago, Hyogo Prefecture (56) Reference JP-A-57-1419 (JP, A) SAIKAI 53-105551 (JP , U)

Claims (2)

[Claims] 1. A pair of heat exchangers capable of alternately supplying a gas to be dehumidified are provided side by side, and a refrigerator for cooling the heat exchangers to defrost the moisture in the gas to provide dehumidification is provided. , A cold brine circulation line that selectively supplies the cold brine cooled by the evaporator of this refrigerator to the heat exchanger to which the gas is supplied, and the hot brine heated by the condenser of this refrigerator is A low dew point dehumidifying device, characterized in that a warm brine circulation line, which is a circulation line separate from the cold brine circulation line, is provided to the heat exchanger to which gas is not supplied. 2. A pair of heat exchangers capable of alternately supplying the gas to be dehumidified are arranged in parallel, and a refrigerator is provided for cooling the heat exchangers and defrosting the moisture in the gas to dehumidify. , A cold brine circulation line that selectively supplies the cold brine cooled by the evaporator of this refrigerator to the heat exchanger to which the gas is supplied, and gas the hot brine heated by the condenser of this refrigerator. Is provided to a heat exchanger that is not supplied, a warm brine circulation line that is a circulation line different from the cold brine circulation line is provided, and the cold brine can be supplied to a heat exchanger that is not supplied with gas. And a bypass line that bypasses the heat exchanger in the warm brine circulation line.