JP3094781B2 - Vacuum ice making equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum ice making apparatus which can be used in, for example, a center plant in a district heating and cooling system, various manufacturing industries, a municipal waste incineration plant, and the like.

[0002]

2. Description of the Related Art Conventionally, as a technique for obtaining cold heat using heat of 90 to 160 ° C. as main driving energy, for example, an absorption refrigerator using lithium bromide as an absorbent and water as a refrigerant. Has been put to practical use.

[0003] Of these, single-effect absorption refrigerators and double-effect absorption refrigerators are well known. For the principle and structure of these refrigerations, see, for example, “Industrial Heat Pumps” [Akiichi Takada et al.
Reference 1), pages 44 to 88.

In a conventional single-effect refrigerator 200, as shown in FIG. 11, water is sprayed from a nozzle 202 to a surface of a heat transfer tube 203 as a refrigerant of an absorption refrigeration cycle in an evaporator 201.

[0005] Absorber 2 provided in communication with evaporator 201
At 04, the inside of the absorber 204 is depressurized by the action of the concentrated aqueous lithium bromide solution sprayed from the nozzle 205. As a result, the water inside the evaporator 201 evaporates under reduced pressure, and the generated steam flows into the absorber 204. This water vapor is absorbed by the aqueous lithium bromide solution. Evaporator 201
The water that evaporates under reduced pressure inside the heat exchanger cools the refrigerant flowing through the heat transfer tube 203 while flowing down on the outer surface of the heat transfer tube 203. The cold obtained in this way is usually taken out of the apparatus by a refrigerant circulation line 206 and supplied to a cold demand.

On the other hand, a separately provided regenerator 207 includes:
The lithium bromide aqueous solution diluted by the absorber 204 is supplied through the heat exchanger 208 and is heated and concentrated by an external heat source 210 at about 100 ° C. to be sent through the heat transfer tube 209.

[0007] In the condenser 211 provided in communication with the regenerator 207, the steam generated in the regenerator 207 is cooled and condensed by the cooling heat transfer tube 212. Absorber 2 described above
A cooling water at about 32 ° C. is supplied to the inside of a cooling water line 213 provided so as to sequentially pass through the cooling water 04 and the condenser 211, removes heat generated by absorption and condensation, and discharges the outside of the apparatus. .

The aqueous solution of lithium bromide concentrated in the regenerator 211 is sent to the heat exchanger 208, where heat exchange is performed with the aqueous solution of lithium bromide diluted in the absorber 204, and The sensible heat of the aqueous solution is recovered to improve the thermal efficiency of the refrigerator 200.

In the absorption chiller 200 having such a structure, since the cold generated in the evaporator 201 is taken out through the heat transfer tube 203 functioning as an indirect heat exchanger, the refrigerant circulates through the refrigerant circulation line 206. Is impossible to get ice. In addition, the absorption chiller usually has a limit of about 6 ° C. in the temperature of the chilled water obtained, irrespective of whether it is single-effect or double-effect, and a low temperature lower than that is not obtained.

The single-effect absorption refrigerator has been described above.
In the double effect absorption refrigerator, the regenerator is divided into two stages, high pressure and low pressure, and the steam of about 100 ° C generated in the high pressure regenerator is reused as a heat source for heating the low pressure regenerator. , With improved thermal efficiency. Details are described in Reference 1.

On the other hand, the present applicant has developed an absorption refrigerator 220 provided with a vacuum ice making container 221 as shown in FIG. 12 in order to solve the above-mentioned disadvantages of the absorption refrigerator. JP-A-5-332648). The absorption refrigerator 220 has the following improvements in order to improve the disadvantage that the absorption refrigerator 200 shown in FIG. 11 cannot make ice.

(A) Instead of an evaporator for taking out cold heat with an indirect heat exchanger (heat transfer tube), a vacuum ice making vessel 221 is provided in communication with an absorber 222, and water circulating as a refrigerant of an absorption refrigerator is provided. Is flash-evaporated inside the vacuum ice-making container 221 and a part thereof is frozen to obtain an ice-water slurry 223.

(B) An ice heat storage tank 225 is provided in the water circulation line 224 so that stable operation of the refrigerant can be ensured so that the water can be continuously operated even if the refrigerant water is frozen. I have to.

(C) A vacuum ice making container 221 operated under vacuum conditions so that a large amount of ice slurry can be stored at low cost.
In contrast, an ice storage tank 225 of an open-to-atmosphere type is separately provided, and an ice slurry 223 generated in a vacuum ice making container 221 is taken out by a pump 226 at a high pressure and stored in the ice storage tank 225.

(D) The vacuum ice making vessel 221 and the absorber 22 are used for the purpose of downsizing the absorber 222 and using water of about 32 ° C. obtained by a usual cooling tower as cooling water.
2, a mechanical auxiliary compressor 227 is provided. These improvements have enabled the production and storage of ice slurries by absorption chillers driven by heat as the primary driving energy.

[0016]

However, FIG.
In the absorption type refrigerator 220 capable of making ice, the operating pressures of the vacuum ice making container 221 and the absorber 222 are about 4.5 Torr and about 8 Torr, respectively, and are set relatively low. For this reason, if the duct 228 connecting the vacuum ice-making container 221 and the absorber 222 is lengthened, the pressure loss accompanying the flow of the low-pressure steam increases, and the absorber 2
The operating pressure of 22 decreases. If the width of heat rise by the auxiliary compressor 227 is increased in order to prevent this, the required power of the auxiliary compressor 227 is greatly increased. As another means for reducing the pressure loss, it is conceivable to make the duct 228 thicker, but this increases equipment cost and is not economically preferable. For this reason, the above-mentioned absorption refrigerator 220 capable of making ice comprises a vacuum ice-making container 221 and an absorber 222.
Must be provided close to each other, and the entire apparatus becomes large-scale.

Further, the above-mentioned absorption refrigerator 22 capable of making ice can be used.
In the case of No. 0, the vacuum ice making vessel 221 and the ice heat storage tank 225 were separately provided, and the ice heat storage tank 225 was opened to the atmosphere, thereby reducing the manufacturing cost of the ice heat storage tank 225.
The water circulating in the absorption refrigerator 220 is supplied to the ice heat storage tank 22.
Since the air comes into contact with the air at 5, there is an opportunity for the air to dissolve in the water. The non-condensable gas such as air dissolved in water in this way is discharged from the vacuum ice making container 221 and reaches the absorber 222. For this reason, the load of the vacuum pump 229 for exhausting the non-condensable gas connected to the absorber 222 increases, and the exhaust of the non-condensable gas is not sufficiently performed, and the non-condensable gas is mixed in the absorber 222. Then, the condensation of water vapor, that is, the absorption into the absorbent is inhibited. In addition, the coexistence of air promotes corrosion of the absorber heat transfer tube 230 provided inside the absorber 222.

The present invention has been made in view of the above circumstances, and eliminates the need to dispose a vacuum ice-making container and an absorber in close proximity, and causes a problem caused by mixing of air into a refrigerant. It is an object of the present invention to provide a vacuum ice making device without any.

The present invention is a vacuum ice making device comprising an absorption refrigerator, a refrigerant circulation line and a vacuum ice making unit, wherein the absorption refrigerator makes the first refrigerant evaporate by an evaporator, and then evaporates. Cold heat is obtained by utilizing the pressure-reducing action of absorbing the gas phase portion of the first refrigerant with the absorbent, and the vacuum ice making section is maintained at a pressure condition equal to or lower than the triple point pressure of ice and supplied. A vacuum ice-making container for evaporating part of the water and freezing the remaining water with latent heat due to the evaporation of the water, steam vaporized in the vacuum ice-making container provided on the downstream side of the vacuum ice-making container A compressor that is provided on the downstream side of the compressor and cools and condenses steam evaporated in the vacuum ice making container by a steam cooling heat exchanger provided therein ; and vacuum
Cooling water is provided from an ice storage tank that is installed in an ice making container and is open to the atmosphere.
A cooling water supply pipe for supplying the refrigerant; and the refrigerant circulation line circulates the second refrigerant through the refrigerant cooling heat exchanger provided inside the evaporator and the steam cooling heat exchanger. A vacuum ice making device (hereinafter, referred to as a first vacuum ice making device) characterized in that cold heat generated in the evaporator is used for cooling the steam in the condenser. provide.

Further, the present invention is a vacuum ice making apparatus comprising an absorption refrigerator, a refrigerant circulation line and a vacuum ice making section, wherein the absorption refrigerator flash-evaporates the refrigerant with an evaporator and then evaporates the refrigerant. Water is obtained by utilizing the decompression effect by absorbing the gas phase portion of the refrigerant into the absorbent, and the vacuum ice making section is maintained at a pressure condition equal to or lower than the triple point pressure of ice, and supplied water is supplied. A vacuum ice making container that freezes a part of the remaining water by latent heat of the evaporation of the water, and a water vapor evaporated in the vacuum ice making container provided on the downstream side of the vacuum ice making container. A compressor that compresses, a condenser that is provided on the downstream side of the compressor and cools and condenses water vapor evaporated in the vacuum ice making container by a water vapor cooling heat exchanger provided therein ; and
It is installed in a vacuum ice-making container and is opened from the open-air ice storage tank.
After providing a cold water supply pipe for supplying cold water , the refrigerant circulation line takes out the refrigerant circulated by the absorption refrigerator from the evaporator and sends it to the inside of the steam cooling heat exchanger. A vacuum ice making device (hereinafter, referred to as "cooling device") which is provided so as to be returned to the evaporator again, whereby cold generated by the evaporator is used for cooling the steam in the condenser. (Second vacuum ice making device).

In the second vacuum ice making device,
The refrigerant of the absorption refrigerator is water, the absorbent is lithium bromide, and the operating pressure in the evaporator is 4.6 to 6.5 Torr.
r, and the temperature of the refrigerant when it is supplied to the steam cooling heat exchanger of the vacuum ice making section is preferably in the range of 0 to 5 ° C.

Hereinafter, the present invention will be described in more detail. In the first vacuum ice making device of the present invention, the absorption refrigerator obtains cold heat by utilizing a decompression effect by evaporating a refrigerant in an evaporator and then absorbing a vapor phase portion of the evaporated refrigerant into an absorbent. Things. This absorption refrigerator uses, for example but not limited to, water as a refrigerant.
As the absorbent, lithium bromide, lithium chloride, calcium chloride, magnesium chloride or other salts or a mixture thereof, or sulfuric acid, acid or alkali such as sodium hydroxide, a large difference in boiling point from water. In addition, a substance having high water solubility can be used in the form of an aqueous solution. Particularly preferably, the refrigerant is water and the absorbent is lithium bromide.

Further, the absorption refrigerator removes the heat generated by the exothermic reaction when the refrigerant absorbs the absorbent by using, for example, water at about 32 ° C. obtained in a cooling tower as cooling water. For example, using a heat source of 90 to 160 ° C. (for example, exhaust heat of a turbine condenser in a refuse incinerator) as main driving energy to absorb a refrigerant and regenerate a diluted absorbent. It may have a heat cycle. Further, the absorption refrigerator may be a single effect type or a double effect type.

The cold generated in the evaporator of the absorption refrigerator is exchanged with the second refrigerant circulating in the indirect type heat exchanger for cooling the refrigerant provided inside the evaporator. Is performed. As a result, about 6 ° C.
Is discharged. The second refrigerant is, for example, water or brine.

In the vacuum ice making section, for example, water at a temperature of about 5 ° C. or less is continuously supplied to the vacuum ice making vessel, and at the same time, the pressure inside the vacuum ice making vessel is reduced to a pressure not higher than the triple point pressure of water by a compressor. Is frozen to form an ice-water slurry. At this time, the pressurized steam at the outlet side of the compressor undergoes heat exchange with the refrigerant sent through the inside of the condenser by the steam cooling heat exchanger to be cooled. The cooled water vapor becomes a drain and is returned to the vacuum ice making vessel. Here, the temperature of the refrigerant used for cooling the steam is raised to about 9 ° C.

In the refrigerant cooling heat exchanger provided in the evaporator of the first vacuum ice making apparatus, the second refrigerant flowing through the heat exchanger and the first refrigerant flowing down the outer surface of the heat exchanger are provided. And a temperature difference of about 3 ° C. is required on average, and the temperature of the second refrigerant in the heat exchanger is higher. This is due to the heat transfer and the heat transfer resistance associated with the heat transfer in the indirect type refrigerant cooling heat exchanger.

On the other hand, in the second vacuum ice making apparatus, cooling is performed by flushing the refrigerant in an evaporator of an absorption refrigerator, and a part of the cooled refrigerant is directly condensed through a refrigerant circulation line. The steam is supplied to the steam heat exchanger for cooling, and is used for cooling steam. For this reason, since steam can be cooled with low-temperature cooling water (0 to 5 ° C.) as much as there is no heat transfer resistance, the second refrigerant of about 6 ° C. in the case of the first vacuum ice making device is used. The condensing pressure inside the condenser is lower than at times. For example, in the first vacuum ice making device, the condensation pressure when the second refrigerant at 6 ° C. is supplied to the steam cooling heat exchanger is 11 Torr. On the other hand, in the second vacuum ice-making machine, since the refrigerant at 3 ° C. can be supplied, the condensation pressure is as low as 8 Torr. As a result, the pressure increase width required for the compressor can be reduced, and a simple type compressor such as a single-stage centrifugal compressor can be used.

In the second vacuum ice making apparatus of the present invention, the refrigerant of the absorption refrigerator is water, the absorbent is an aqueous solution of lithium bromide, and the operating pressure of the evaporator of the absorption refrigerator is 4. When the pressure is 6 to 6.5 Torr and the temperature of the refrigerant supplied to the steam cooling heat exchanger is 0 to 5 ° C., the compression ratio required by the compressor is lower than about 2.0. This reduces the problem of the strength of the material of the compressor, so that a simpler type of compressor can be used.

Here, the relationship between the operating pressure of the evaporator and the temperature of the refrigerant (water) supplied to the steam cooling heat exchanger is determined by the relationship between the saturation temperature of water and the pressure. That is, the water temperature T
Is 0 ° C., the saturation pressure Ps is 4.6 Torr,
When the water temperature T is 5 ° C., the saturation pressure Ps is 6.5 Torr.
r. Therefore, the temperature of the water can be controlled by adjusting the flow rate, pressure or temperature of the external heat source supplied to the absorption refrigerator, or the flow rate of the cooling water. The control of the temperature of the refrigerant (water) supplied to the steam-cooling heat exchanger can be performed by applying a refrigerant temperature control method in a conventional absorption refrigerator. For example, this temperature control method can be performed according to the control flow shown in FIG.

[0030]

According to the first vacuum ice making device of the present invention, the heat exchanger for cooling the refrigerant provided inside the evaporator of the absorption refrigerator and the heat exchanger for cooling the steam provided inside the condenser are provided. A refrigerant circulation line for sequentially transmitting and circulating the second refrigerant to the system, and a system for compressing steam evaporated in a vacuum ice making vessel with a compressor and then cooling and condensing the steam with a steam cooling heat exchanger. It has become. For this reason, since the absorption chiller side and the vacuum ice making part side are connected by a pipe constituting a refrigerant circulation line, it is possible to reduce the diameter of the required pipe, and the distance between the two can be reduced. There is no need to arrange them in close proximity. Further, since the first refrigerant and the second refrigerant and the water vapor do not mix with each other, non-condensable gas such as air does not enter the absorption type refrigerator from the vacuum ice making part side.

Similarly, the second vacuum ice making apparatus of the present invention also takes out a part of the refrigerant circulated by the absorption refrigerator from the evaporator of the absorption refrigerator, and removes a part of the refrigerant inside the heat exchanger for steam cooling. And a steam circulation line arranged to return to the evaporator and flash inside the evaporator again, and the steam evaporated in the vacuum ice making vessel is compressed by the compressor and then cooled by the heat exchanger for steam cooling. And the system that is condensed
It is a different system. For this reason, since the absorption chiller side and the vacuum ice making part side are connected by a pipe constituting a refrigerant circulation line, it is possible to reduce the diameter of the required pipe, and the distance between the two can be reduced. There is no need to arrange them in close proximity. In addition, since the refrigerant and the steam do not mix, non-condensable gas such as air does not enter the absorption refrigerator from the vacuum ice making unit side. Further, since the refrigerant cooled by flash evaporation is directly used, the refrigerant is lower in temperature than the first vacuum ice making device because of no heat transfer resistance, and therefore the required condensation pressure inside the condenser is lower. And the step-up width required by the compressor becomes smaller.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a first embodiment of the vacuum ice making device of the present invention. A in the figure is a vacuum ice making unit. The vacuum ice making unit A includes a vacuum ice making container 11. Evaporation ice maker 1
1 has a cold water supply pipe 12 for continuously supplying cold water.
Is connected. The cold water supply pipe 12 is provided with a pump 13. Further, an ice discharge pipe 14 for discharging generated ice is connected to the bottom of the evaporating ice making container 11. The ice discharge pipe 14 is provided with a pump 15.

On the downstream side of the vacuum ice making vessel 11, the compressor 1
6 are connected. An ice making unit side condenser 17 is connected to the downstream side of the compressor 16. Inside the ice making part side condenser 17, a steam cooling heat exchanger 18 is provided. Further, a vacuum pump 19 is connected to the ice making unit side condenser 17. Further, a drain return pipe 20 is provided between the ice making unit side condenser 17 and the vacuum ice making vessel 11.

In the figure, B denotes a single-effect absorption refrigerator. Absorption refrigerator B has evaporator 21 and evaporator 2
A nozzle 22 for spraying water is disposed on the upper part of the nozzle 1. A heat exchanger 23 for cooling the refrigerant is provided inside the evaporator 21.

An absorber 24 is provided in communication with the evaporator 21. A nozzle 25 for dispersing a concentrated aqueous solution of lithium bromide, which is an absorbent, is disposed above the absorber 24. Inside the absorber 24, a heat transfer tube 27 in the absorber through which the refrigerator-side cooling water 26 is passed is disposed. A non-condensable gas discharge vacuum pump 36 is connected to the absorber 24. Further, one end of a pipe 28 for discharging a diluted aqueous solution of lithium bromide is connected to the bottom of the absorber 24, and the other end is connected to a heat exchanger 29 for an absorbent. A pump 30 is provided in the middle of the pipe 28.

On the other hand, in a regenerator 31 provided separately, an aqueous solution of lithium bromide diluted in the absorber 24 is supplied with the heat exchanger 2.
There is provided a nozzle 32 which is supplied via 9. Further, inside the regenerator 31, an external heat source 33 of about 100 ° C.
A heat transfer tube 34 inside the regenerator through which the heat is transmitted is disposed. In this embodiment, hot water of 98 ° C. was used as the external heat source 33. Further, a pipe 35 for supplying the concentrated aqueous solution of lithium bromide to the heat exchanger 29 for an absorbent is connected to the bottom of the regenerator 31. In the middle of the pipe 35,
A pump 37 is provided. At the outlet of the concentrated aqueous solution of lithium bromide in the heat exchanger 29 for the absorbent, a pipe 37 is provided.
Is connected, and the terminal is connected to the nozzle 25 of the absorber 24.

A refrigerator-side condenser 41 is provided in communication with the regenerator 31. Inside the refrigerator-side condenser 41, a condenser-side heat transfer tube 42 through which the refrigerator-side cooling water 26 sent through the above-described absorber-side heat transfer tube 27 is sent is arranged. Here, as the refrigerator-side cooling water 26, water having a temperature of 32 ° C. obtained in a cooling tower (not shown) was used.

One end of a condensed water return pipe 43 for discharging condensed water is connected to the bottom of the refrigerator-side condenser 41. The nozzle 22 is connected to the other end of the condensed water return pipe 43. Condensate return pipe 4
In the middle of 3, a pipe 44 connected to the bottom of the evaporator 21 for discharging water that has not evaporated is connected, and further a pump 45 is provided on the downstream side.

One end of a pipe 51 is connected to the outlet side of the refrigerant cooling heat exchanger 23 provided inside the evaporator 21, and the other end of the pipe 51 is connected to the ice making unit condenser 1.
7 is connected to the inlet side of a steam cooling heat exchanger 18 provided inside. In the middle of the pipe 51, a pump 52
Is provided. A pipe 53 is provided between the outlet of the steam-cooling heat exchanger 18 and the inlet of the nozzle 22 attached to the evaporator 21. Water is circulated as a refrigerant inside the refrigerant circulation line C having such a configuration.

On the other hand, a cold storage facility D is disposed below the vacuum ice making section A. The cold storage facility D includes an ice heat storage tank 53 that is open to the atmosphere. Inside the ice heat storage tank 53, the terminal portion of the cold water supply pipe 12 described above is arranged so as to be immersed when the ice water slurry 54 is stored. A terminal portion of the ice discharge pipe 14 is located above the opening of the ice heat storage tank 53.

In the ice heat storage tank 53, heat exchange is performed between the cold water supply line 55 for directly delivering the ice water slurry 54 to the cold heat demand destination and supplying the cold heat, and the ice water slurry 54, and the cooled refrigerant is delivered. Thus, a cold heat supply line 56 for supplying cold heat to a cold heat demand destination is provided.

In the vacuum ice making apparatus 10 configured as described above, first, cold water is continuously supplied to the vacuum ice making vessel 11 from the ice heat storage tank 53 by the pump 13 through the cold water supply pipe 12. On the other hand, the compressor 16 is driven to suck the water vapor inside the vacuum ice making container 11, and the pressure inside the vacuum ice making container 11 is reduced to a pressure lower than the triple point pressure of water (4.6 Torr) (4.5 Torr in the present embodiment). At the same time, the steam is pressurized and sent to the ice making unit side condenser 17. In this condenser 17,
The pressurized steam is cooled and condensed by the steam cooling heat exchanger 18 to form a drain. This drain is returned to the vacuum evaporation container 11 via the drain return pipe 20. Here, the condensation temperature in the condenser 17 is 11 ° C.
And the condensing pressure is set at about 10 Torr. Since the internal pressure of the vacuum ice making device 17 is 4.5 Torr,
The pressure ratio required for compressor 16 is 2.22. Therefore,
Assuming that a centrifugal compressor is used as the compressor 16, this pressure ratio can be obtained by a centrifugal compressor having two compression stages and an intercooler.

On the other hand, inside the vacuum ice making container 11, a part of the cold water is frozen to form sherbet-like ice. The ice is extracted by the pump 15 via the discharge pipe 14 and stored in the ice heat storage tank 53 in the form of an ice water slurry 54.

The steam cooling refrigerant used in the steam cooling heat exchanger 18 is obtained in the endothermic refrigerator B and cooled using cold heat. Absorption refrigerator B
Is the same as in the prior art, and
It is described in. As described above, an aqueous solution of lithium bromide is used as the absorbent, water (hereinafter, circulating water in the refrigerator) is used as the refrigerant, and the external heat source 33 (98
° C warm water), and 3
When water at 2 ° C. is used, the temperature of the
Of cold was obtained. In the refrigerant cooling heat exchanger 23,
The circulating water in the refrigerator at about 3 ° C. flowing down the outer surface of the heat transfer tube of the heat exchanger 23 inside the evaporator 21 cools the refrigerant sent through the heat transfer tube. As a result, the refrigerant is cooled to about 6 ° C. This refrigerant is supplied to the steam cooling heat exchanger 18 by the pump 52 via the pipe 51 as described above, and is used for cooling the steam in the vacuum ice making unit side condenser 17. The temperature of the refrigerant discharged from the steam cooling heat exchanger 18 has been raised to about 9 ° C.

On the other hand, the cold stored in the ice heat storage tank 53 as the latent heat of the ice water slurry 54 is directly taken out of the ice water slurry 54 by the cold heat supply line 55 and is directly supplied to the cold heat demand destination as the latent heat of the ice. The ice water slurry 54 in the indirect heat exchanger 56a of the cold heat supply line 56;
The refrigerant (water) cooled by performing heat exchange with the refrigerant is supplied to the cold energy demand destination as sensible heat of the refrigerant.

In the above-described vacuum ice making device 10, the refrigerant cooling heat exchanger 23 provided in the evaporator 21 of the absorption refrigerator B and the steam cooling heat exchanger 23 provided in the vacuum ice making unit side condenser 17 are provided. A refrigerant circulation line C for sequentially sending and circulating a refrigerant through a heat exchanger 18 and a vapor 16 evaporated in a vacuum ice making container 11 are compressed by a compressor 16, and this steam is then vaporized in a vacuum ice making part side condenser 17. Cooling heat exchanger 18
It is a separate system from the system that cools and condenses the water. Therefore, between the absorption refrigerator B side and the vacuum ice making section A side,
The pipes 51 and 53 of the refrigerant circulation line C are connected by pipes 51 and 53.
It is possible to reduce the thickness to about one-half, and there is no need to arrange them close to each other, so that the space saving of the entire apparatus can be achieved.

A refrigerant circulation line C and a vacuum ice making section A
Is separated from the system for condensing the water vapor, so that the refrigerant flowing through the refrigerant circulation line C and the condensed water vapor do not mix with each other. Therefore, non-condensable gas such as air does not enter the absorption refrigerator B side from the vacuum ice making part A side. As a result, the load on the non-condensable gas discharging vacuum pump 36 attached to the absorber 24 of the absorption refrigerator B can be reduced, and the condensation of water vapor in the absorber 24 (absorption into the aqueous lithium bromide solution) is inhibited. Can be prevented. Further, it is possible to prevent the heat transfer tube 27 in the absorber from being corroded due to air being mixed in the steam generated in the evaporator 21.

In the cold storage facility D, since the open-to-atmosphere ice heat storage tank 53 is used, the structure is simple and the manufacturing cost can be relatively low. Further, since the obtained cold heat can be stored as latent heat of the ice water slurry 54, it is possible to easily cope with a change in the amount of cold heat demand as compared with a case where the directly generated ice water slurry is supplied to the cold heat demand destination. be able to. That is, for example, when the waste heat from a garbage incineration plant in a large city is used as the main driving energy of the absorption refrigerator B and used for cooling in the surrounding area, the driving heat source and the driving power are supplied in substantially constant amounts. Therefore, since it is an appropriate and simple operation method to make the ice making speed almost constant throughout the day, there is no particular problem even when the ice water slurry generated by the vacuum ice making device 10 is directly supplied. However, the cooling demand in the surrounding area is high during the day and low at night. When the cold heat generation rate and the cold heat demand do not match, the ice heat storage tank 53 buffers the difference between the cold heat demand and supply, and serves as a buffer that enables stable cold heat generation and cold heat use. Can work. More specifically, when the demand for cold heat at night is small, excess cold heat is accumulated in the ice heat storage tank 53 as latent heat of ice, and when the demand for cold heat increases during the day, the generation of cold becomes insufficient. Can be used to supplement

FIG. 2 is an explanatory view showing a second embodiment of the vacuum ice making device of the present invention. Vacuum ice making device 60 of the present embodiment
Is provided with a vacuum ice making unit A and a regenerator D having the same configuration as the vacuum ice making device 10 of the first embodiment, but by flashing and evaporating water in an evaporator 61 of an absorption refrigerator B ′. In addition to cooling, the water cooled at this time (hereinafter referred to as circulation cooling water) is taken out to a cooling water circulation line C ′ and supplied directly to the steam cooling heat exchanger 18 of the vacuum ice making unit side condenser 17. However, it differs from the vacuum ice making device 10 of the first embodiment in that it is used for cooling steam. That is, a spray nozzle 62 for flushing the circulating cooling water is provided above the evaporator 61 of the absorption refrigerator B '. In the spray nozzle 62,
A terminal of a condensed water return pipe 63 for returning water condensed from the refrigerator-side condenser 41 is connected, and at the same time, a pipe 64 connected to an outlet side of the steam cooling heat exchanger 18 is connected.

On the other hand, the bottom of the evaporator 61 is
A pipe 66 for taking out the circulating cooling water 65 cooled by the flash evaporation in the inside and supplying it to the inlet side of the steam cooling heat exchanger 18 is connected. A pump 67 is provided in the middle of the pipe 66.

The temperatures of the external heat source 33 and the cooling water 26 on the refrigerator side are the same as in the first embodiment. In the vacuum ice making device 60 as described above, water is flushed from the spray nozzle 62 into the evaporator 61, which is in a reduced pressure state due to the absorption reaction in the absorber 24, and is cooled to evaporate. 65 are obtained. The obtained cooling water for circulation 6
5 is about 3 ° C. The temperature of the obtained cooling water 65 for circulation is controlled by a control valve V ₁ for controlling the supply amount of the external heat source 33.
Alternatively, a control valve V ₂ for adjusting the supply amount of the refrigerator-side cooling water 26 is provided to provide the external heat source 33 or the refrigerator-side cooling water 2.
6 can be controlled by adjusting the supply amount. That is, as shown in FIG. 2, a temperature detector 68 is attached to a pipe 66 for supplying the cooling water 65 to the heat exchanger 18 for cooling water vapor, and the temperature T ₁ of the cooling water 65 is measured. If the temperature T ₁ rises above a set value by a control unit (not shown), the opening of the control valve V ₁ is increased to increase the flow rate of the external heat source 33, and the odor in the absorber 24 is increased. Increase the concentration of the lithium chloride solution. As a result, absorber 2
4, the operating pressure of the evaporator 61 communicating with the absorber 24 decreases, and the temperature T of the circulating cooling water 65 decreases.
₁ drops. Also, by increasing the supply amount of the refrigerator side coolant 26 to increase the regulating valve V ₂ denotations opening, absorber to promote heat removal at 24, absorber circulating cooling water operation even while reducing the pressure of it is possible to lower the temperature T ₁ of the 65. When the temperature T ₁ of the circulation cooling water 65 is lower than the set value, the temperature T ₁ can be increased in a completely reverse procedure.

The circulating cooling water 65 is supplied to the steam cooling heat exchanger 18 of the vacuum ice making unit side condenser 17 via the pipe 66 by the pump 67 and used for cooling the steam. The temperature of the circulating cooling water discharged from the outlet side of the steam cooling heat exchanger 18 is raised to about 9 ° C. This cooling water for circulation is returned to the spray nozzle 62 via the pipe 64. In the spray nozzle 62, the cooling water for circulation from the cooling water circulation line C 'returned through the pipe 64 and the condensed water returned from the condenser-side condenser 41 of the absorption refrigerator B' are combined and flushed. You. However, it is not always necessary to combine both, and the evaporators 6 are separately provided.
You can return to 2.

The vacuum ice making device 60 as described above can exhibit the same effect as the vacuum ice making device 10 of the first embodiment. Further, in the vacuum ice making device 60 of this embodiment, cooling is performed by flushing water in the evaporator 61, and the obtained cooling water for circulation 65 is exchanged for heat for steam cooling through the pipe 67 of the refrigerant circulation line C '. The water is supplied to the vessel 18 and used for cooling the steam. Therefore, the steam can be cooled by the circulating cooling water at a low temperature of about 3 ° C. as much as there is no heat transfer resistance, so that the refrigerant of about 6 ° C. in the case of the vacuum ice making device 10 of the first embodiment is used. Compared to when
The condensation pressure inside the vacuum ice making unit side condenser 17 can be reduced. For example, when the cooling water for circulation at 3 ° C. is supplied to the heat exchanger 18 for cooling steam, the condensation pressure in the condenser 17 is 8 Torr. As a result, the step-up width required by the compressor 16 can be reduced, so that the compressor 16
A simple type such as a single-stage centrifugal compressor can be used. Further, the required power of the compressor 16 is greatly reduced.

As the heat cycle of the absorption refrigerator B ', not only a single-effect cycle but also a double-effect cycle can be used. However, when using double-effects,
It is necessary to use an external heat source 33 for driving having a temperature of 150 to 160 ° C.

Next, a modification of the flash type evaporator 61 will be described. The evaporator 71 shown in FIG. 3 includes a plurality (for example, two) of spray nozzles 72. Thereby, the water is finely sprayed and the evaporation area is enlarged.

The evaporator 81 shown in FIG. 4 is not provided with a spray nozzle but is provided with a stirrer 82 to improve the mixing of the liquid while stirring the water 83 and to make the surface of the water rippling to enlarge the evaporation area. Can be evaporated.

The evaporator 91 shown in FIG. 5 has a plurality of shelves 92 provided substantially horizontally therein, and the water 93 supplied from the pipe 64 flows down along the shelves 92 so that the evaporator 91 has an evaporation area. Can be increased.

The evaporator 101 shown in FIG. 6 has a plurality of vertical plates 102 arranged substantially vertically inside. Water is sprayed from the spray nozzle 103 and sprayed on the surface of the vertical plate 102 to form a falling liquid film 104 to increase the evaporation area. In addition, water is similarly sprayed on the inner wall surface of the evaporator 101 to increase the evaporation area.

In the evaporator 111 shown in FIG. 7, a plurality of horizontal tubes 112 are arranged substantially horizontally in multiple stages. Water is sprayed from a spray nozzle 113 and sprayed on the surface of the horizontal tube 112 to form a falling liquid film 114 to increase the evaporation area. The horizontal tube 112 may be a rod instead of a tube.

Next, a modified example of the heat storage equipment D will be described. Vacuum ice making device 1 of first and second embodiments
At 0 and 60, the heat storage equipment D including the open-to-atmosphere ice heat storage tank 53 is provided. However, when the supply of the heat source and the demand for the cold heat are always constant as described above, FIG. As described above, without providing an ice heat storage tank, the sherbet-shaped ice generated in the vacuum ice making container 11 is delivered to the cold heat demanding destination via the pipe 121, while water returned from the cold heat demanding destination or fresh water is piped. It can also be supplied to the vacuum ice making container 11 via 122.

As shown in FIG. 9, a closed type ice heat storage tank 123 can be used in place of the open-air type ice heat storage tank. As a result, the incorporation of air can be completely prevented, and the amount of non-condensable air accumulated in the vacuum ice making unit side condenser 17 can be reduced. Therefore, the load of the vacuum pump 19 for discharging the air can be reduced. Can be reduced. Further, as shown in FIG. 10, in a small-scale system, an ice cold storage container 124 having both the function of a vacuum ice making container and the function of an ice heat storage tank can be used.

[0062]

According to the first vacuum ice making device of the present invention, the refrigerant circulation line and the vacuum ice making unit are separate systems, so that the refrigerant circulation line is provided between the absorption refrigerator and the vacuum ice making unit. Will be connected with each other. For this reason, it is possible to reduce the required diameter of the pipe, and it is not necessary to arrange the two close to each other. As a result, space saving of the entire apparatus can be easily achieved.

Further, since the first refrigerant in the absorption refrigerator and the second refrigerant in the refrigerant circulation line and the water vapor in the vacuum ice making unit do not mix with each other, the absorption type refrigerator is moved from the vacuum ice making unit side to the absorption refrigerator. Non-condensable gas such as air does not enter. For this reason, the load of the vacuum pump for discharging the non-condensable gas on the absorption cooler side can be reduced. Further, condensation of water vapor (absorption into the solvent) can be prevented, and furthermore, corrosion of the outer surface of the heat transfer tube in the absorber due to the mixture of air can be prevented.

Also, in the second vacuum ice making apparatus of the present invention, the refrigerant circulation line and the vacuum ice making section are separate systems. The load of the vacuum pump for non-condensable gas can be reduced, the condensation of water vapor can be prevented, and the outer surface of the heat transfer tube in the absorber due to the mixture of air can be prevented from being corroded. Furthermore, the cooling water for circulation obtained by flash evaporation of the refrigerant in the evaporator is directly supplied to the heat exchanger for steam cooling, so that the heat transfer is in comparison with the case where the refrigerant is indirectly cooled by heat exchange. There is no resistance and the temperature drops. Since this low-temperature circulating cooling water is directly introduced into the heat exchanger for steam cooling of the condenser and used, the condensing pressure of the condenser is reduced, the pressure increase width required by the compressor is reduced, and the compressor is simple to use. The type can be used. As a result, a relatively inexpensive compressor can be used, and the running cost of the compressor can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of a vacuum ice making device according to the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the vacuum ice making device of the present invention.

FIG. 3 is an explanatory view showing a modification of the evaporator in the second embodiment.

FIG. 4 is an explanatory view showing a modification of the evaporator in the second embodiment.

FIG. 5 is an explanatory view showing a modification of the evaporator in the second embodiment.

FIG. 6 is an explanatory view showing a modification of the evaporator in the second embodiment.

FIG. 7 is an explanatory view showing a modification of the evaporator in the second embodiment.

FIG. 8 is an explanatory view showing a main part of the vacuum ice making device of the present invention having no cool storage equipment.

FIG. 9 is an explanatory view showing a modification of the ice heat storage tank in the vacuum ice making device of the present invention.

FIG. 10 is an explanatory view showing a modification of the ice heat storage tank in the vacuum ice making device of the present invention.

FIG. 11 is an explanatory view showing a conventional absorption refrigerator.

FIG. 12 is an explanatory view showing a conventional absorption refrigerator.

[Explanation of symbols]

10, 60: vacuum ice making device, 11, 61: vacuum ice making container, 16: compressor, 17: vacuum ice making section side condenser, 18 ...
Heat exchanger for steam cooling, 21 ... Evaporator, 22 ... Nozzle,
23 heat exchanger for cooling refrigerant, 24 absorber, 26 cooling water on refrigerator side, 29 heat exchanger for absorbent, 31 regenerator,
33: external heat source, 41: condenser side condenser, 53: ice regenerator, 54: ice water slurry, 55, 56: cold heat supply line, 62: spray nozzle.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-164974 (JP, A) JP-A-5-332648 (JP, A) JP-A-63-243665 (JP, A) JP-A-60-1985 62539 (JP, A) JP-B 36-17125 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25C 1/16

Claims (3)

(57) [Claims] 1. A vacuum ice making device comprising an absorption refrigerator, a refrigerant circulation line, and a vacuum ice making unit, wherein the absorption refrigerator evaporates a first refrigerant by an evaporator, and then evaporates the first refrigerant. The cold heat is obtained by utilizing the decompression action by absorbing the gas phase portion of the refrigerant into the absorbent, and the vacuum ice making section is maintained at a pressure condition equal to or lower than the triple point pressure of ice, and supplied water is supplied. A vacuum ice making container that partially evaporates and freezes a part of the remaining water by the latent heat of the water evaporation, and compresses the water vapor evaporated by the vacuum ice making container provided on the downstream side of the vacuum ice making container. A compressor that is provided on the downstream side of the compressor and cools and condenses steam evaporated in the vacuum ice making container by a steam cooling heat exchanger provided therein ; and the vacuum ice making.
Supplied with ice water from an open-air ice storage tank
A cooling water supply pipe for circulating the second refrigerant through the refrigerant cooling heat exchanger and the steam cooling heat exchanger provided inside the evaporator. Wherein the cold generated by the evaporator is used for cooling the steam in the condenser. 2. A vacuum ice making device comprising an absorption refrigerator, a refrigerant circulation line, and a vacuum ice making unit, wherein the absorption refrigerator makes the refrigerant flash-evaporate by an evaporator, and then evaporates the evaporated refrigerant. The cold part is obtained by utilizing the decompression effect by absorbing the phase part into the absorbent, and the vacuum ice making part is maintained at a pressure condition equal to or lower than the triple point pressure of ice, and a part of the supplied water is A vacuum ice-making container for evaporating and freezing part of the remaining water by the latent heat of the evaporation of the water, and a compressor for compressing water vapor evaporated in the vacuum ice-making container provided on the downstream side of the vacuum ice-making container A condenser provided on the downstream side of the compressor, for cooling and condensing steam evaporated in the vacuum ice making container by a steam cooling heat exchanger provided therein , and the vacuum ice making
Supplied with ice water from an open-air ice storage tank
A cooling water supply pipe for removing the refrigerant circulated in the absorption refrigerator from the evaporator, and sends the refrigerant to the inside of the steam cooling heat exchanger, and then evaporates the refrigerant again. A vacuum ice making device provided so as to be returned to a vessel, whereby cold heat generated in the evaporator is used for cooling the steam in the condenser. 3. The refrigerant of the absorption refrigerator is water, the absorbent is an aqueous solution of lithium bromide, the operating pressure in the evaporator is in the range of 4.6 to 6.5 Torr, and the vacuum ice making section is used. 3. The vacuum ice making device according to claim 2, wherein the temperature of the refrigerant when supplied to the steam-cooling heat exchanger is in the range of 0 to 5 [deg.] C.