JP4507274B2 - Ice storage type cold water system - Google Patents

Description

  The present invention relates to an ice storage type cold water apparatus for supplying cold water to an air conditioner, a food cooling apparatus or the like.

  2. Description of the Related Art Conventionally, an ice storage type chilled water device is known in which a circulation path is formed between an ice storage tank and a heat exchanger, and a replenishment water path is connected to the heat exchanger inlet side of the circulation path. This seed ice storage type cold water apparatus is referred to as a replenishing water type or an external water supply type. (For example, refer to Patent Document 1). In addition, this ice storage type chilled water device stores ice as a heat storage medium in an ice storage tank using late-night electricity with a low power bill, and defrosts from the top of the ice storage tank according to the load demand. The water is supplied for cooling, and cold water is taken out from the lower part of the ice storage tank.

  This type of external water supply type apparatus has the following problems. In general, when the supercooled state is continuously performed, the supercooled state is destroyed in the heat exchanger, and the heat exchanger is often frozen. Therefore, conventionally, when the heat exchanger 1 is frozen, for example, the operation of the freezer is stopped and the freeze release operation such as supplying room temperature water from the external water supply channel for a predetermined time is performed. As a result, in the conventional apparatus, since the operation of the refrigerator is stopped and the freeze release operation is performed, the ice storage time becomes longer and energy loss occurs.

Japanese Patent Laid-Open No. 9-152149

  The problem to be solved by the present invention is to shorten ice storage time and to reduce energy loss.

This invention was made in order to solve the said subject, The invention of Claim 1 is the heat exchanger which produces | generates supercooling water, the ice storage tank which stores ice and cold water, and the said heat exchange In an ice storage type chilled water device comprising a circulation path between the storage device and the ice storage tank and a replenishment water path to the inlet side of the heat exchanger, an overcooling is carried out by setting the outlet temperature of the heat exchanger to zero degrees or less. Switching between the cooling operation and the non-supercooling operation in which the outlet temperature of the heat exchanger exceeds zero degree and not supercooling is performed, and the non-supercooling in the second set time every time the supercooling operation in the first set time is performed. A supercooling control means for performing operation is provided , and the ratio between the first set time and the second set time is adjusted according to the make- up water temperature of the make-up water channel .

According to the present invention, by applying the non-supercooling operation every predetermined time, the number of times of freezing of the heat exchanger can be reduced, and the energy loss due to defrosting (freezing release) can be reduced. Freeze solution
The ice storage time can be shortened by reducing the number of removals .

  Next, an embodiment of the present invention will be described. The embodiment of the present invention is implemented in a replenishment water type (external water supply type) ice storage type cold water apparatus.

First, an outline of this embodiment will be described. The ice storage type chilled water device of this embodiment is formed between a heat exchanger that generates supercooled water, an ice storage tank that stores ice and cold water, and the heat exchanger and ice storage tank. In an ice storage type chilled water apparatus comprising a circulation path and a makeup water path for supplying makeup water to the inlet side of the heat exchanger in the circulation path, a supercooling operation for supercooling by the heat exchanger and the heat exchanger A supercooling control means for adjusting a time ratio with a non-supercooling operation without supercooling is provided.

  In this embodiment, the water in the ice storage tank is supercooled by the heat exchanger while circulating in the circulation path. A part of the supercooled water is released from supercooling and becomes ice, and is stored in the ice storage tank. Then, make-up water is supplied to the inlet side of the heat exchanger through the make-up water channel, the cold water from the ice storage tank and the make-up water are mixed, and the mixing ratio of the make-up water so that the mixed water temperature becomes a predetermined temperature. Is controlled. And since the time of non-supercooling operation is provided by the supercooling control means, the heat exchanger is prevented from freezing. Here, freezing prevention includes not only completely preventing freezing but also reducing the number of freezing.

  Next, components of this embodiment will be described. The heat exchanger has a function of supercooling water circulating in the circulation path, and preferably cools the circulating water by indirectly exchanging heat with a refrigerant of a cooling means such as a refrigerator. . This heat exchanger employs a double tube type structure or the like.

  The ice storage tank stores cold water and ice. The circulation path is formed with the heat exchanger, and water in the ice storage tank is circulated in the circulation path, and supercooled by the heat exchanger, thereby storing cold water and ice. This circulation path is provided with a circulation pump.

  The makeup water channel is supplied with makeup water on the inlet side of the heat exchanger, and is mixed with cold water from the ice storage tank. The amount of makeup water is adjusted so that the inlet temperature on the inlet side of the heat exchanger becomes a set value.

  The supercooling control means adjusts the time ratio between the supercooling operation and the non-supercooling operation so that the heat exchanger does not freeze. This time ratio is set in advance by experiments.

  The switching between the supercooling operation and the non-supercooling operation is preferably performed by adjusting the temperature (inlet temperature) of the mixed water flowing into the heat exchanger, but the supply flow rate to the heat exchanger It can also be realized by adjusting (feed water flow rate), that is, the amount of mixed water. When the cooling capacity of the heat exchanger per unit time is constant, in the former case, when the temperature of the mixed water is lowered, a supercooling operation can be performed. In the latter case, a non-supercooling operation can be performed when the amount of mixed water is increased, and a supercooling operation can be performed when the amount of water is decreased. Furthermore, the switching between the non-supercooling operation and the supercooling operation can be performed by changing the capacity of the heat exchanger cooling refrigerator.

  Hereinafter, specific Example 1 of the ice storage type cold water apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of the first embodiment.

  The outline of the first embodiment will be described with reference to FIG. A replenishing water type ice storage type cold water apparatus shown in FIG. 1 includes a heat exchanger 1 that generates supercooled water, an ice storage tank 2 that stores ice and cold water, and the heat exchanger 1 and ice storage tank 2. The main part includes a circulation path 3 formed therebetween, a makeup water path 4 for supplying makeup water to the inlet side of the heat exchanger 1 in the circulation path 3, and a supercooling control means that is a feature of the present invention. Yes. The supercooling control means adjusts the time ratio between the supercooling operation in which the heat exchanger 1 is supercooled and the non-supercooling operation in which the heat exchanger is not supercooled, thereby freezing the heat exchanger 1. It has the function to prevent.

  Next, each component of this embodiment will be described. The heat exchanger 1 is an indirect heat exchanger having a double tube structure capable of supercooling water circulating in the circulation path 3 with a refrigerant. The refrigerant side of the heat exchanger 1 constitutes a partial evaporator of the refrigerator 6. The refrigerator 6 includes a compressor 7, a condenser 8, a decompressor 9, and the heat exchanger 1 as an evaporator, and these are connected by a refrigerant circuit (reference numeral omitted).

  The ice storage tank 2 is a tank for storing cold water and ice, and is connected to the heat exchanger 1 and the circulation path 3. The ice storage tank 2 includes a first water level detector 11 that detects a low water level and a second water level detector 12 that detects full water. One end 13 of the circulation path 3 opens below the detection end of the first water level detector 11 of the ice storage tank 2, and the other end 14 opens at the upper end of the ice storage tank 2. ing. The circulation path 3 includes a circulation pump 15 and forms a cold water circulation path including the ice storage tank 2, the circulation pump 15, the heat exchanger 1, and the ice storage tank 2.

  The replenishment water channel 4 includes a first valve 16 whose opening degree can be adjusted, one end is connected to a water supply source (not shown) such as water supply, and the other end is the ice storage tank 2 of the circulation channel 3 and the circulation. Connected between the pumps 15. Thereby, makeup water is supplied and mixed with cold water from the ice storage tank on the inlet side of the heat exchanger 1.

  The ice storage tank 2 is connected to an ice-melting water channel 18 having a second valve 17. One end of the de-icing water channel 18 is branched from the upstream side of the first valve 16 of the replenishing water channel 4, and the other end is configured as a water spray port 19 for spraying water in a shower-like manner. The water spout 19 is opened above the detection end of the second water level detector 12.

  In addition, the ice storage tank 2 is provided with a cold water supply path 21 for taking out the cold water generated by the ice melting and supplying the cold water to equipment (not shown). The cold water supply path 21 has a water supply pump 22, one end of which opens to the inner bottom of the ice storage tank 2.

  Here, the supercooling control means will be described. This supercooling control means has a freeze prevention function and an ice filling rate control function. This anti-freezing function is a function of preventing freezing of the heat exchanger 1 by adjusting the time ratio between the supercooling operation and the non-supercooling operation. The ice filling rate control function adjusts the time ratio between the supercooling operation and the non-supercooling operation by adjusting the temperature of the mixed water (feed water) flowing into the heat exchanger 1 according to the makeup water temperature. It is a function to control the ice filling rate.

  The supercooling control means includes a first temperature detector 23 that detects a makeup water temperature of the makeup water channel 4, a second temperature detector 24 that detects an inlet temperature to the heat exchanger 1, and these temperatures. A controller 25 that receives signals from the detectors 23 and 24 and controls the opening degree of the first valve 16 is included.

  The controller 25 switches between the supercooling operation and the non-supercooling operation by controlling the temperature of the mixed water flowing into the heat exchanger 1 according to the makeup water temperature in accordance with a pre-stored processing procedure. At the same time, the anti-freezing control and the ice filling rate control are performed by adjusting the time ratio. The controller 25 also performs control of the entire ice storage operation and control of taking out cold water.

In this embodiment, when the cooling temperature of the heat exchanger 1 (temperature difference between the inlet and the outlet) is set to 1.5 ° C., for example, the mixed water temperature is set to 0.5 ° C. which is the first set temperature T1. By setting the outlet temperature of the heat exchanger 1 to −1.0 ° C. which is less than or equal to zero degree, the supercooling operation is performed, and the mixed water temperature is set to 2.0 ° C. which is the second set temperature T2, and A non-supercooling operation is performed by setting the outlet temperature to 0.5 ° C. exceeding zero degrees. The numerical value demonstrated here is an example and can be changed variously.

  The freeze prevention control performs the non-supercooling operation only for the second set time t2 (for example, 10 minutes) every first set time t1 (for example, 1 hour) so that the supercooling operation does not continue for a predetermined time or longer. Consists of.

  In addition, the control of the time ratio for optimizing the ice filling rate is performed as follows. If the make-up water temperature is low, the ice filling rate will be low, so the supercooling operation time (ice storage time) will be lengthened, and if the make-up water temperature is high, the ice filling rate will be high. Increase the cooling operation time (cold water production time). That is, by adjusting the ratio of the supercooling operation time and the non-supercooling operation time according to the makeup water temperature, the ice filling rate is controlled to the set value regardless of the change in the makeup water temperature. The ratio control between the supercooling operation time and the non-supercooling operation time is performed by changing the ratio stepwise or continuously by changing the makeup water temperature. When controlling in stages, the makeup water temperature is divided into, for example, three stages, and the ratio is varied for each stage.

  The operation of the embodiment having the above configuration will be described. First, ice storage operation performed using midnight power will be described. After putting water into the ice storage tank 2 to the detection end of the first water level detector 11, the refrigerator 6 is started and the circulation pump 15 is started to supply water in the ice storage tank 2 through the circulation path 3. To the heat exchanger 1. And the supercooled water produced | generated by heat exchange returns to the ice storage tank 2, and a supercooled state is cancelled | released by colliding with a dispersion plate (illustration omitted), and produces | generates slurry-like ice.

  When the temperature of the cold water flowing into the heat exchanger 1 decreases, the temperature decrease is detected by the second temperature detector 24, the opening degree of the first valve 16 is adjusted, and the room temperature through the supply water channel 4 is normal. Is supplied with water and mixed with cold water to obtain mixed water at a predetermined temperature.

  In this ice storage operation, the freeze prevention operation is performed as follows. When the supercooling operation by the heat exchanger 1 is performed for the first set time t1, the operation is switched to the non-supercooling operation, this is continued for the second set time, and the supercooling operation is switched. In this way, by applying the non-supercooling operation every predetermined time, the number of times of freezing of the heat exchanger 1 can be reduced, and energy loss due to defrost (freezing release) can be reduced. In addition, the ice storage time can be shortened by reducing the number of times of freeze release.

  The ice filling rate control operation is performed as follows. The first temperature detector 23 detects the makeup water temperature. When the makeup water temperature is lowered, the supercooling operation is performed by adjusting the opening of the first valve 16 so that the mixed water temperature becomes the first set temperature T1, and the time ratio of the supercooling operation is increased. And control the ice filling rate to be high. On the contrary, when the makeup water temperature rises, the opening degree of the first valve 16 is adjusted so that the mixed water temperature becomes the second set temperature T2, and the non-cooling operation is performed. Reduce the rate to control the ice filling rate to be small. By adjusting the operation time ratio between the supercooling operation and the non-supercooling operation according to the makeup water temperature, the ice filling rate is controlled to a desired set value. This ice storage operation is performed until full water is detected by the detection end of the first water level detector 12.

Next, the cold water extraction operation will be described. When there is a request for cold water supply, the water supply pump 22 is driven and the second valve 17 is opened. As a result, room-temperature water is supplied from the sprinkling port 19 into the ice storage tank 2 through the ice-breaking water channel 18, and cold water is taken out from the cold-water supply channel 21 while performing ice melting. In this ice-melting operation, the ice filling rate is controlled to an appropriate value, so that the conventional problem can be solved. That is, in the conventional device that does not control the ice filling rate, if the ice filling rate is large, there is a problem that the cold water supply from the ice storage tank cannot catch up with a large amount of cold water load for a short time, and the ice filling rate is small However, when the total amount of cold water load is large, there is a problem that this cannot be answered, but according to this embodiment, such a problem can be solved or improved.

It is a schematic block diagram of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Ice storage tank 3 Circulation path 4 Replenishment water path 25 Controller (supercooling control means)

Claims (1)

A heat exchanger 1 that generates supercooled water, an ice storage tank 2 that stores ice and cold water, a circulation path 3 between the heat exchanger 1 and the ice storage tank 2, and the heat exchanger 1. In an ice storage type chilled water device comprising a replenishment water channel 4 to the inlet side,
While switching between a supercooling operation in which the outlet temperature of the heat exchanger 1 is subcooled below zero and a non-supercooling operation in which the outlet temperature of the heat exchanger 1 is over zero degrees and not supercooled, A supercooling control means for performing the non-supercooling operation for a second set time each time the supercooling operation is performed , and the ratio between the first set time and the second set time is the makeup water temperature of the makeup water channel 4 An ice storage type chilled water device that is adjusted according to the temperature.

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