JP2548637B2 - Operating method of supercooled water production 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 method of operating a supercooled water production apparatus for ice making in an ice heat storage facility in which heat source water for air conditioning is stored in the form of ice.

[0002]

2. Description of the Related Art In cooling and heating by circulating cold and hot water through a water-side heat exchanger of a fan coil unit and a water heat source heat pump unit disposed in a building, the cooling heat generated during cooling is stored in an ice storage tank. Attention has been paid to what is called the ice thermal storage method, which is used for storage at the plant. For example, a refrigerator is driven by nighttime electric power to make ice, a large amount of cold heat is stored in a heat storage tank in the state of ice, and during cooling operation, the cold heat of the ice is taken out as cold water and supplied to a secondary heat exchanger. Since it circulates and uses the latent heat of water, even small-scale equipment can store a large amount of cold heat.

[0003] In this ice heat storage method, the form of ice to be stored depending on the ice making method is divided into an ice block (solid) and a sherbet (liquid or slurry in which fine ice and water are mixed). Divided. Although both have advantages and disadvantages, in the case of the ice block method, when the ice block is generated in the heat storage water tank (generated on the surface of the heat exchanger), the thicker the ice layer, the lower the heat conduction, and the larger the thickness. Is limited, and therefore the ice filling rate (I.
PF) is only around 10%, and it is inevitable that the heat storage efficiency will deteriorate. Although it has been reported that a special solution containing an additive is used to improve the IPF and the heat storage water tank itself is configured as a pressure vessel, the heat storage type water heat source cooling and heating equipment of an existing building is used as it is for ice heat storage. There are many problems when applied to the method.

On the other hand, when producing sherbet-like ice, the IPF can be made very large. However, in order to make large-volume water into a sherbet-like form, a very large-scale facility is generally required. Regarding this sherbet-like heat storage method, for example, JP-A-63-123968-9 and JP-A-63-1
Those described in the publications 29274-5 are known. Further, Japanese Patent Application Laid-Open Nos. 63-217171 and 6 related to the same applicant
3-231157 proposes a method and an apparatus for making fine ice from supercooled water, and on the condition that the supercooled water is continuously manufactured by a heat transfer tube, the improvement thereof is required.
JP 63-271074, JP 64-75869, JP 64-90973, JP 1-114682, JP 63-1
No. 39459, No. 1-88235, No. 1-88236, No. 1-88237, No. 1-97135, No. 1-112345, No. 1-120022 Bulletin, Actual Kaihei
No. 125940, No. 1-136832, No. 1-48538
Various proposals have been made to the official gazette, the utility model 1-178528, the utility model 2-527, etc.

In any case, the supercooler of the ice making system for producing sherbet-like ice from the supercooled water proposed in these publications has a heat transfer tube through which water flows, disposed in a cooling vessel. Either brine of a refrigerator is passed through the cooling vessel as a cooling medium, or the cooling vessel is configured to function as an evaporator of a heat pump device. These are collectively called a supercooler in the present invention. Although the inner wall temperature of the heat transfer tube in the subcooler is below 0 ° C but maintained at -5.8 ° C or higher, it does not freeze within the tube regardless of fluctuations in the inlet temperature and flow rate of water. It has already been clarified that a continuous flow of supercooled water can be taken out (for example, Japanese Patent Application Laid-Open No. 1-114682).

[0006]

When the supercooled water is discharged as a continuous flow from the discharge port of the heat transfer tube of the subcooler, when the heat transfer tube is arranged in the lateral direction, the discharge flow is parabolic in the atmosphere. Will draw and fall. This parabola causes the streamline to spread near the end, the parabola itself changes depending on the discharge pressure and flow rate, and when discharged from many heat transfer tubes simultaneously, the discharge flows may touch each other. For this reason, a supercooler in which heat transfer tubes are placed horizontally has the advantage that the effect of gravity on the flow inside the tubes can be reduced, but the discharge flow tends to spread or change. For this reason, it is necessary to make the receiving area in the tank relatively large. In addition, the splash may rebound near the discharge port of the heat transfer tube, and ice may adhere and grow outside the pipe near the discharge port.

If the supercooled water is dropped in the vertical direction with the heat transfer tube set in the vertical direction, the above-mentioned problem of the horizontal type can be solved.
The present inventors repeated the test by making a large number of heat transfer tubes vertical, but the water flowing in the heat transfer tubes was subjected to the action of gravity so that the water did not flow evenly in each tube and the supercooled water was stabilized. I experienced that I could not manufacture it. When this non-uniformity was severe, one tube saw freezing problems. JP-A-63-271074 mentioned above
In Japanese Patent Laid-Open Publication No. 64-75869, Japanese Utility Model Laid-Open No. 1-88236, etc., an example of a subcooler with a vertical heat transfer tube was proposed, but similar problems may occur in this case as well. .

The present invention has been made in order to find the conditions under which stable production of supercooled water is possible even with such a vertical subcooler.

[0009]

According to the present invention, in a cooling container in which a cooling medium flows, a large number of heat transfer tubes are vertically arranged, penetrating through the upper and lower walls of the container. The upper end of each heat transfer tube is opened in the header container provided in the upper part of the heat transfer tube, the lower end of the heat transfer tube is opened to the atmosphere near the lower wall of the cooling container, and the lower end of each heat transfer tube is continuously supplied to the header container. When performing ice making for ice heat storage for air conditioning using a supercooled water production device (subcooler) that continuously discharges supercooled water cooled to below 0 ° C from the opening, the header detecting the pressure in the vessel, forcibly pumping sufficient amount of water to the header vessel pressure during the operation of the supercooled water production apparatus (subcooler) does not become negative pressure
It continued and said Rukoto.

[0010]

EXAMPLE FIG. 1 shows an example of an ice storage facility for air conditioning to which the method of the present invention is applied. 1 is a heat storage tank, 2 is a supercooler, 3 is a circulation pump, and the water in the heat storage tank 1 is a pump 3
Is continuously supplied to the subcooler 2 through the water channel 4 by
The supercooler 2 turns into supercooled water 5 at a temperature of 0 ° C. or below and discharges it into the atmosphere. The discharge flow of the supercooled water 5 collides with the dispersion plate 6 and drops into the heat storage tank 1. This dispersion plate 6
The supercooled state is released by the impact of falling onto the ice cubes, and the ice cubes become fine ice.

As shown, the subcooler 2 comprises a vertical shell-and-tube heat exchanger in which a large number of heat transfer tubes (tubes) 9 are vertically arranged in a shell 10. Each tube 9 (hereinafter referred to as heat transfer tube 9) is arranged so as to penetrate through the upper and lower walls of a shell 10 (hereinafter referred to as a cooling container 10),
Since the upper end opens into the header container 11 and the lower end opens to the atmosphere, the water introduced into the header container 11 flows vertically down each heat transfer tube 9 and enters the atmosphere from the discharge port 15 at the lower end. Discharge vertically. The inner wall temperature of each heat transfer tube 9 is 0 ° C in running water.
Below, the temperature is controlled to be maintained at a temperature of -5.8 ° C or higher.

In the shell side cooling container 10, the inner wall temperature of each heat transfer tube 9 is set to 0 ° C. or lower and −5.8 ° C. or higher.
Each heat transfer tube 9 is cooled from its outer wall. As the cooling medium, brine manufactured by a refrigerator can be used, but in the illustrated example, it functions as an evaporator of a heat pump device. That is, evaporator (that is, cooling vessel 10), compressor 12, condenser 13, expansion valve 14, evaporator 10
, A heat pump device is configured with a refrigerant circuit that sequentially passes through the heat pump device. The cooling vessel is driven by driving this heat pump device.
10 serves as an evaporator and cools each heat transfer tube 9 to the above temperature.
It should be noted that the heat pump device can be assembled so as to form a boiling evaporator that fills the cooling container 10 with a refrigerant liquid and boil the liquid refrigerant by the heat received from the heat transfer tube 9.

In this way, according to the present invention, a vertical subcooler in which a large number of heat transfer tubes 9 are arranged in the vertical direction is provided, and its discharge port
Although supercooled water is dropped from 15 into the heat storage tank 1 as a vertical discharge flow, as described above, a large number of heat transfer tubes 9 (for example,
When the temperature of the supercooling water discharged from each heat transfer tube 9 was measured when using a subcooler in which (81 pieces) were arranged, it was experienced that variations occurred. At other times, some tubes may freeze.

It has been found that this problem can be solved by a simple method of sending a water amount from the pump 3 so that the header container 11 does not have a negative pressure. That is, the header container
When the water supplied to the inside of the header 11 flows down through each heat transfer tube 9, if a negative pressure is generated in the header container 11 due to the suction action of the falling water, a phenomenon such that a certain heat transfer tube attracts air from the open end 15 may occur. It is presumed that the cause is that
As a result, the degree of supercooling of the supercooled water discharged from the tank varies, but it was found that this fluctuation can be completely avoided by maintaining the positive pressure in the header container 11. Therefore,
According to the present invention, during operation of the subcooler, a sufficient amount of water for maintaining the positive pressure in the header container 11 is forcedly and continuously injected from the pump 3.

In carrying out the present invention, a pressure gauge 16 for detecting the pressure in the header container 11 is attached, and when the indicated value of the pressure gauge 16 becomes a negative pressure for some reason, the pump 3 is stopped, It is preferable to stop the heat pump device as well. Further, the pump 3 is a variable rotation speed pump, the rotation speed of the pump is maintained so that the pressure gauge 16 maintains a predetermined positive pressure, and in that state, the required cooling capacity in the cooling container is controlled. A mechanism can also be adopted. In any case, the implementation of the present invention
As shown in FIG. 1, the header container 11 is open to the atmosphere.
It is better not to have such an opening. That is,
Only the open end 15 of each heat transfer tube 9 is opened to the atmosphere.
Then, for example, Japanese Patent Laid-Open No. 63-271074,
As described in JP-A-1-114682
It is better not to install the overflow pipe in the header container 11.
Yes.

The pressure in the header container 11 depends on the frictional resistance between the inner wall of the heat transfer tube 9 and water and the amount of water (water speed). This is also related to the number of pipes, pipe diameter, pipe length, pipe material, header container capacity (head), etc. According to the present invention, whatever the number of such factors is, only the pressure in the header container 11 is used as an indication value, and the supplied water amount is maintained so as not to become a negative pressure. It was found that the freezing trouble of the vertical subcooler can be avoided with only such control factors.

For example, the dimensions of each part shown in FIG. 2 are: L (cooling length of heat transfer tube 9) = 3950 mm, M (internal height of header container 11) = 350 mm, N (height of header container water supply port 17) ) = 225 mm, inner diameter = 7.5 mm, outer diameter = 9.5 mm In a supercooler that uses 81 tubes, the pressure inside the header container becomes 0 mAq at a circulating water volume of about 460 l / min, and below It became clear that the negative pressure became positive and the positive pressure became higher than this, and as long as this positive pressure was maintained, there was no variation in supercooling degree.

Similarly, L (cooling length of heat transfer tube 9) = 3960 mm, M (internal height of header container 11) = 347 mm, N (height of header container water supply port 17) = 222 mm, inner diameter = With a supercooler that uses 81 heat transfer tubes with an outer diameter of 8.0 mm and an outer diameter of 9.0 mm, the pressure inside the header container becomes 0 mAq when the circulating water flow rate is about 550 l / min. Below this pressure is negative pressure, above this pressure is positive pressure. Therefore, it was found that the supercooling did not fluctuate as long as this positive pressure was maintained.

As described above, even if the shape and size of the supercooler are different, if control is performed to secure the amount of water such that the pressure in the header container does not become a negative pressure, the supercooled water discharged from the multiple heat transfer tubes 9 Variations in temperature can be avoided, and the vertically downward supercooling water flow can be stably taken out from the vertical subcooler 2. The supercooled water collides and reflects on the dispersion plate 6 to release the supercooled state, and the ice droplets generated disperse and fall into the heat storage tank 1, and the sheared ice 7
Accumulates.

Water (cold water) coexisting with the ice 7 in the heat storage tank 1 is circulated to the water side heat exchanger of a fan coil unit or a heat pump unit arranged in the building, though not shown. It is supplied to the heat source water (cold heat source) for air conditioning and is returned to the inside of the heat storage tank 1 again. The operation of the supercooled water production system (operation of the heat source equipment) and the air conditioning operation (operation of the load side) can be performed simultaneously, and the former can be stored at night by using inexpensive nighttime electric power and stored. It may be used for cooling in the daytime. In the heating operation, the supercooled water production device is stopped, hot water is stored in the heat storage tank 1 by a heat source device (not shown) such as a boiler or a heat pump device, and the hot water is supplied to the load side.

Although FIG. 1 shows an example in which the evaporator of the heat pump device is used as a cooling container, brine produced by a refrigerator is continuously supplied to the cooling container to cool the heat transfer tube 9. Good.

[0022]

According to the present invention, since the heat transfer tube of the subcooler is of a vertical type and the supercooled water is discharged vertically downward from the heat transfer tube, the discharge flow does not draw a curve and the water flow is eliminated. The pattern is stable. Even in the vertical type, the supercooled water discharged from a large number of heat transfer tubes has no variation in the degree of supercooling, and it is possible to stably produce supercooled water while avoiding freezing troubles. By adopting this vertical type supercooler, the opening area of the heat storage tank is smaller than that of the horizontal type subcooler, and therefore it can be constructed as a vertically long heat storage tank. A vertically long heat storage tank is advantageous in separating the specific gravity of ice and water, and can increase the filling rate of ice and reduce the installation area. Therefore, even if it is small, it can be configured as an ice heat storage device having a sufficient heat storage capacity.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an entire ice storage facility for air conditioning to which the present invention is applied.

FIG. 2 is a front view for explaining the dimensions of the supercooler of FIG.

[Explanation of symbols]

 1 heat storage tank 2 supercooler 3 pump 5 continuous flow of supercooled water 6 dispersion plate 7 sherbet ice 9 heat transfer tube 10 cooling vessel 11 upper header 12 compressor 13 condenser 14 expansion valve 16 pressure gauge 17 header vessel water inlet

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazunori Eto 4-15-12 Morino, Machida, Tokyo Terada Building Morino B-311 (72) Inventor Mitsuru Moriya 3-7-25 Sagamigaoka, Zama, Kanagawa Prefecture Sunlight Hills 203 (72) Inventor Masayuki Tanino 2-8-21-101 Kyowa, Sagamihara-shi, Kanagawa (56) Reference JP-A-63-271074 (JP, A) JP-A-1-114682 (JP, A) Actual Kaihei 2-527 (JP, U)

Claims (4)

(57) [Claims] 1. A plurality of heat transfer tubes are vertically arranged in a cooling container in which a cooling medium flows, penetrating through the upper and lower walls of the container, and each heat transfer pipe is provided in a header container provided on the upper part of the cooling container. The upper end of each heat transfer tube was opened and the lower end of the heat transfer tube was opened to the atmosphere in the vicinity of the lower wall of the cooling container, and water was continuously passed through the header container to cool the heat transfer tube to below 0 ° C from the lower end opening. When performing ice making for ice heat storage for air conditioning using a supercooled water production device that continuously discharges supercooled water , the pressure in the header container is detected to operate the supercooled water production device. how the operation of the supercooled water production apparatus sufficient amount of water to the pressure does not become negative pressure, characterized in Rukoto continued forcibly pumped into the header vessel at medium. Wherein the supercooled water production apparatus is installed above the water surface of the heat storage tank, the supercooled water which discharges into a separating diffusion plate from the heat transfer tube
How the operation of the supercooled water production apparatus according to claim 1 for dropping the thermal storage tank after having allowed to collision. 3. The method for operating a supercooled water producing apparatus according to claim 1, wherein the water supplied to the header container is the water in the ice heat storage tank which is forcibly pumped by a pump. 4. A heat transfer tubes are according to claim 1 in which the inner wall temperature is maintained at a temperature of more than -5.8 ° C. at zero ° C. or less, 2 or
3. The method for operating the supercooled water producing apparatus according to item 3 .