JP2005300044A - Ice making method and device by supercooling brine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ice making device capable of stably making ice regardless of the variation of concentration of brine supplied to a supercooling heat exchanger in accompany with the variation of ice making quantity, and free from problems such as freezing of brine in the supercooling heat exchanger. <P>SOLUTION: In this ice making method for supercooling the brine by vaporized latent heat of liquid refrigerant supplied from a freezer by the supercooling heat exchanger 1, and then releasing the supercooled state of the brine to make ice slurry 13 in which the brine and small pieces of ice are mixed, the difference between a temperature of the supercooled brine at an outlet of the supercooling heat exchanger 1 and a temperature of ice slurry after releasing the supercooling is kept constant. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ice making method and an ice making apparatus for producing a sherbet-like ice slurry in which brine and ice pieces are mixed by supercooling the brine.

  A device that generates sherbet-like ice slurry in which ice strips are mixed with water by supercooling fresh water into supercooled water and then releasing the supercooled state by applying shocks such as vibration to the supercooled water The ice slurry produced by such an apparatus and method is fluid and easy to convey, and can use the latent heat of ice, so it has good energy efficiency. There is an advantage that there is a dynamic type, that is, widely used as a cold source for an ice heat storage device of a type that supplies ice generated outside the heat storage tank (ice storage tank) to the heat storage tank (for example, Patent Document 1, 2).

  By the way, if the ice making water is not pure water but is brine as described above, the sensible heat and latent heat are large as in the case of using fresh water. Therefore, if the brine is used as a cold medium, Can be sent to the heat storage tank, and the low-temperature brine stored in the heat storage tank is sent from the heat storage tank to, for example, a low-temperature air conditioning facility and can be effectively used as a cold heat source.

However, in the conventional apparatus and method that uses fresh water as ice making water, the freezing temperature does not change even if the ice making amount is large, but in the case of brine, the frozen portion (solid phase) relative to the total amount of brine in the entire brine circuit When the ratio of γ increases, the concentration of the non-freezing portion (liquid phase) increases, and when the brine concentration increases, the freezing point decreases as shown in the graph of FIG.
The data shown in the graph shows the relationship between the brine concentration of a brine made of a propylene / glycol aqueous solution and the freezing point (freezing temperature).

  Therefore, when the brine is circulated between the heat storage tank and the ice making device like the ice heat storage device, the brine freezing point in the initial stage of ice making where the ice storage amount is small and the ice making end stage where the ice storage amount is large There is a significant temperature difference from the stage brine freezing point. That is, in the initial stage of ice making, the cooling heat necessary for brine supercooling in the final stage of ice making is large compared to the cold heat required to supercool the brine, and therefore the evaporation temperature of the liquid refrigerant is in the final stage of ice making. However, it is necessary to set the temperature low so that sufficient ice making can be performed.

  However, if the evaporation temperature of the liquid refrigerant is set to a low temperature so that stable ice making is possible at the end of ice making, the cooling capacity becomes excessive in the initial ice making stage, and the temperature of the brine in the supercooling heat exchanger is required. The temperature becomes lower than the above, and the supercooling heat exchanger cannot be maintained, and more specifically, the supercooling heat exchanger is frozen, more specifically, at the outlet of the supercooling heat exchanger where the temperature of the inner surface of the pipe wall becomes the lowest. There is a risk that the brine flow path of the cooling heat exchanger is blocked and ice making stops.

The above-mentioned problems do not only occur in the ice making method and apparatus used in the ice heat storage device. For example, the ice slurry is directly sent to a load side heat exchanger such as a heat exchanger for air conditioning to use the cold heat. This is also a problem that occurs in the same way.
Japanese Patent Laid-Open No. 5-180467 (pages 1 to 5, FIGS. 1 to 4) Japanese Patent Laid-Open No. 5-296503 (pages 1 to 3, FIGS. 1 to 3)

  The object of the present invention is that stable ice making can be performed even if the concentration of brine supplied to the supercooling heat exchanger fluctuates with changes in the ice making amount, and therefore heat exchange for supercooling. An object of the present invention is to provide an ice making device that does not cause a problem such as freezing of a brine in a vessel.

  In order to solve the above-mentioned problem, the method according to claim 1 of the present invention is such that the brine is supercooled by the supercooling heat exchanger by the latent heat of vaporization of the liquid refrigerant supplied from the refrigerator, and then the brine is supercooled. In the ice making method of generating an ice slurry in which brine and ice chips are mixed by releasing the state, the temperature of the supercooled brine at the outlet of the supercooling heat exchanger and the temperature of the ice slurry after the supercooling is released The difference is maintained at a constant value.

  In the method according to claim 2 of the present invention, the difference between the temperature of the supercooling brine and the temperature of the ice slurry is maintained at a constant value by controlling the evaporation pressure of the liquid refrigerant in the supercooling heat exchanger. It is characterized by that.

  In the method according to claim 3 of the present invention, the difference between the temperature of the supercooling brine and the temperature of the ice slurry is maintained at a constant value by controlling the supply amount of the ice-making brine to the supercooling heat exchanger. It is characterized by doing so.

  According to a fourth aspect of the present invention, there is provided a supercooling heat exchanger for supercooling ice-making brine by latent heat of vaporization of liquid refrigerant supplied from a refrigerator having a compressor and a condenser, and the same heat exchange. An ice slurry generator for generating an ice slurry in which the brine and ice strips are mixed to release the supercooled state of the brine supercooled by the cooler in this order. A brine feed pipe that is sent to the cooling heat exchanger; and an ice slurry feed pipe that sends the ice slurry from the ice slurry generator to the load side, and the temperature of the supercooling brine at the outlet of the supercooling heat exchanger; A control circuit for adjusting the temperature of the supercooled brine is provided so that the difference from the temperature of the ice slurry after the supercooling is released is maintained at a constant value.

  The apparatus according to claim 5 of the present invention is based on a control signal from the control circuit in the middle of the refrigerant return pipe between the refrigerant outlet of the supercooling heat exchanger and the inlet of the compressor in the ice making device. A control valve for adjusting the opening degree is provided, and the temperature of the supercooling brine is adjusted by adjusting the opening degree of the control valve.

  The apparatus according to claim 6 of the present invention is provided with a brine pump that adjusts the amount of liquid to be fed based on a control signal from the control circuit in the middle of the brine pipe, and adjusts the amount of liquid to be fed by this brine pump. Thus, the temperature of the supercooling brine is adjusted by controlling the amount of brine supplied to the supercooling heat exchanger.

  As described above, according to the present invention, even if the brine concentration changes according to the ice making amount, and the brine freezing point, that is, the temperature of the ice slurry fluctuates due to the change in the brine concentration, the temperature of the ice slurry and the supercooling temperature are changed. The difference between the temperature of the supercooled brine at the brine outlet of the heat exchanger is kept constant, that is, the degree of supercooling of the brine is kept constant, so the brine is overcooled and heat exchange for supercooling There is no problem of freezing in the vessel, and stable ice slurry can be supplied.

Hereinafter, embodiments of the method and apparatus according to the present invention will be described in detail based on specific examples shown in the accompanying drawings.
FIG. 1 shows the configuration of a first embodiment of the apparatus according to the present invention.
In FIG. 1, reference numeral 1 denotes a supercooling heat exchanger, 2 denotes an ice slurry generator, and a brine pipe 4 having one end connected to the lower part (liquid phase side) of the ice heat storage tank 3 is connected to the brine pump 5. The other end of the ice slurry feed pipe 6 connected to the brine inlet 1a of the supercooling heat exchanger 1 and one end connected to the outlet 1b via the ice slurry generator 2, and the lower end 7a of the ice It is connected to the upper end of the ice slurry discharge pipe 7 facing the upper part of the heat storage tank.

  Further, the other end of the refrigerant forward pipe 9 having one end connected to the discharge port 8a of the compressor 8 is connected to the refrigerant inlet 1c of the supercooling heat exchanger 1 via the condenser 10 and the expansion valve 11, and the outlet The other end of the refrigerant return pipe 12 having one end connected to 1d is connected to the suction port 8b of the compressor to constitute a refrigerant circuit.

  The brine sent to the supercooling heat exchanger 1 from the ice heat storage tank 3 through the brine pipe 4 by the drive of the brine pump 5 is cooled to a supercooled state at a temperature lower by about 2 ° C. than the freezing temperature of the brine. It is sent to the generator 2.

  In the ice slurry generator 2, the supercooled brine is subjected to physical action such as vibration and impact to release the supercooled state, and the brine (liquid phase) and ice flakes (solid phase) are separated. It becomes a mixed sherbet-like ice slurry, is sent to the ice heat storage tank 3 by the ice slurry feed pipe 6, and is stored in the tank.

  In the ice heat storage tank 3, the solid phase 13 in the ice slurry is deposited in a floating state above the liquid phase 14, and the brine of the liquid phase 14 is cooled by the latent heat of fusion of the solid phase 13. The brine is sent to a load-side heat exchanger such as an air conditioner (not shown) through the brine forward pipe 15 so that the brine heated by the heat exchanger is returned to the ice heat storage tank 3 by the brine return pipe 16. Reference numeral 17 in FIG. 1 denotes a brine pump for sending brine to the load side, and 18 denotes a nozzle for spraying the heated brine to the solid phase 13 in the ice heat storage tank.

  Therefore, in the apparatus of the present embodiment, immediately after the ice slurry generator 2 in the ice slurry feed pipe 6 of the brine circuit, the temperature of the ice slurry, that is, the current concentration of the ice making brine supplied to the supercooling heat exchanger. Is provided with a temperature sensor 19 for detecting the freezing temperature of the brine corresponding to the above, and a pressure sensor 20 for detecting the refrigerant pressure and a control valve 21 in the vicinity of the refrigerant outlet of the supercooling heat exchanger in the refrigerant return pipe 12 of the refrigerant circuit. The temperature sensor 19, the pressure sensor 20, and the control valve 21 are provided in this order, and are connected to a control circuit 22 that adjusts the opening degree of the control valve 21 based on signals from the temperature sensor and the pressure sensor.

  Specifically, the control circuit 22 includes a calculation unit 23, a pressure / temperature conversion unit 24, and a temperature control unit 25. An ice slurry temperature signal from the temperature sensor 19 is input to the calculation unit 23, and the pressure The pressure signal from the sensor 20 is converted into a temperature signal by the pressure / temperature conversion unit 24 and is input to the calculation unit 23 as a refrigerant evaporation temperature signal. In the calculation unit 23, the ice slurry temperature signal and the refrigerant evaporation temperature signal are converted into ice. The difference between the slurry temperature and the refrigerant evaporation temperature is calculated and a temperature difference signal is output to the temperature control unit 25. The temperature control unit 25 calculates the difference between the ice slurry temperature and the refrigerant evaporation temperature based on the temperature difference signal. A control signal for adjusting the opening degree is output to the control valve 21 so that the temperature difference between the ice slurry and the refrigerant is kept at a constant value so as to be equal to the set temperature difference inputted from Adjusting the evaporation pressure of the liquid refrigerant in the subcooling heat exchanger 1, the evaporation temperature are configured to be controlled in response to the evaporation pressure.

  More specifically, as the amount of ice stored in the ice heat storage tank increases and the concentration of brine supplied to the supercooling cooler for ice making increases, the freezing temperature of the brine, i.e., the temperature of the ice slurry, increases, and thus the ice slurry temperature. Therefore, the temperature control unit increases the opening degree of the control valve 21 to decrease the evaporation pressure, that is, to lower the refrigerant evaporation temperature.

  In addition, when the amount of ice stored in the ice heat storage tank decreases and the concentration of brine supplied to the supercooling cooler for ice making decreases, the freezing temperature of the brine, that is, the temperature of the ice slurry, decreases, so the ice slurry temperature and the refrigerant Since the difference in evaporation temperature becomes large, the temperature control unit decreases the opening degree of the control valve 21 to increase the evaporation pressure, that is, increase the evaporation temperature of the refrigerant.

  As described above, the refrigerant evaporation temperature is adjusted in accordance with the temperature change of the ice slurry, so that the temperature of the supercooled brine at the brine outlet of the supercooling heat exchanger 1, that is, the lowest temperature of the brine is also changed to the refrigerant evaporation temperature. The temperature changes correspondingly, and the difference between the temperature of the supercooled brine and the temperature of the ice slurry is controlled to be constant.

FIG. 2 shows the configuration of a second embodiment of the apparatus according to the present invention.
In the apparatus of the second embodiment, the apparatus of the first embodiment adjusts the refrigerant evaporation pressure of the supercooling heat exchanger 1 by adjusting the opening degree of the control valve 21, and changes in accordance with the evaporation pressure. While the refrigerant evaporating temperature is controlled to control the temperature of the supercooled brine, the supply amount of ice making brine to the supercooling heat exchanger 1 is controlled to control the temperature of the supercooled brine. As a configuration.

  That is, the amount of the brine pump 5 provided in the middle of the brine feed pipe 4 is adjusted by a control signal from the temperature control unit 25 of the control circuit 22 to control the amount of brine supplied to the supercooling heat exchanger. It is comprised so that it may do.

  When the amount of brine supplied to the supercooling heat exchanger is controlled in this way, the heat load in the supercooling heat exchanger changes, so that the refrigerant suction pressure is not controlled as in the first embodiment described above. However, the temperature of the supercooled brine can be controlled so that the temperature difference from the ice slurry is constant.

  The second embodiment is the same as the first embodiment except that there is no configuration corresponding to the control valve 21 and that the amount of liquid fed to the brine pump 5 is adjusted by a control signal from the control circuit 22. This is the same as that of the first embodiment.

  In each of the above-described embodiments, the temperature of the supercooling brine is indirectly determined based on the refrigerant evaporation pressure detected in the vicinity of the outlet of the supercooling heat exchanger that changes corresponding to the temperature change of the supercooling brine. However, the temperature of the supercooled brine may be detected directly at the outlet of the heat exchanger for supercooling, such as the wall temperature of the brine feed pipe or the temperature of the supercooled brine in the brine feed pipe. is there.

  In addition, each of the above-described embodiments relates to a configuration in the case where the method and apparatus of the present invention are used as ice making means for an ice heat storage device. It may be configured to be sent to the load side heat exchanger and used as a cold heat source.

The block diagram which shows 1st Example of the apparatus which concerns on this invention. The block diagram which shows 2nd Example of the apparatus which concerns on this invention. The graph which shows the relationship between the density | concentration of a brine, and a freezing point.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supercooling heat exchanger 2 Ice slurry generator 3 Ice heat storage tank 4 Brine pipe 5 Brine pump 6 Ice slurry delivery pipe 7 Ice slurry discharge pipe 8 Compressor 9 Refrigerant forward pipe 10 Capacitor 11 Expansion valve 12 Refrigerant return pipe 13 Brine solid phase 14 Brine liquid phase 15 Brine forward pipe 16 Brine return pipe 17 Brine pump 18 Brine spray nozzle 19 Temperature sensor 20 Pressure sensor 21 Control valve 22 Control circuit 23 Calculation unit 24 Pressure / temperature conversion unit 25 Temperature control unit

Claims (6)

  The brine is supercooled by the heat exchanger for supercooling by the latent heat of vaporization of the liquid refrigerant supplied from the refrigerator, and then the brine supercooled state is released to generate an ice slurry in which the brine and ice chips are mixed. In the ice making method, the brine subcooling is characterized in that the difference between the temperature of the supercooled brine at the outlet of the supercooling heat exchanger and the temperature of the ice slurry after the supercooling is released is maintained at a constant value. By ice making method.   The difference between the temperature of the supercooled brine and the temperature of the ice slurry is maintained at a constant value by controlling the evaporation pressure of the liquid refrigerant in the supercooling heat exchanger. Ice making method by supercooling of brine.   2. The difference between the temperature of the supercooling brine and the temperature of the ice slurry is maintained at a constant value by controlling the amount of ice-making brine supplied to the supercooling heat exchanger. The ice-making method by supercooling the brine described in 1.   A supercooling heat exchanger that supercools the ice-making brine by the latent heat of vaporization of the liquid refrigerant supplied from the refrigerator that includes the compressor and the condenser, and the subcooling state of the brine that is supercooled by the heat exchanger. An ice slurry generator that generates an ice slurry in which the brine and ice strips are mixed in this order, and a brine feed pipe that sends the ice-making brine from the load side to the supercooling heat exchanger; and An ice slurry feed pipe for sending ice slurry from the ice slurry generator to the load side, and the difference between the temperature of the supercooling brine at the outlet of the supercooling heat exchanger and the temperature of the ice slurry after the supercooling is released is An ice making device by supercooling of brine, comprising a control circuit for adjusting the temperature of the supercooled brine so as to be maintained at a constant value.   A control valve whose opening degree is adjusted based on a control signal from the control circuit is provided in the middle of the refrigerant return pipe between the refrigerant outlet of the supercooling heat exchanger and the suction port of the compressor in the ice making device. 5. The ice making device according to claim 4, wherein the temperature of the supercooled brine is adjusted by adjusting the opening of the control valve.   Provided in the middle of the brine feed pipe is a brine pump that adjusts the liquid feed amount based on a control signal from the control circuit, and supplies the brine to the supercooling heat exchanger by adjusting the liquid feed amount of the brine pump. The ice making device by supercooling of the brine according to claim 4, wherein the temperature of the supercooled brine is adjusted by controlling the amount.

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