JPH0377433B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a cold heat storage device that utilizes the latent heat of melting of ice, and is particularly suitable for use as a cold heat source for cooling water or as a heat source for heat pumps in a small volume. The present invention relates to a cold storage device that can store a large amount of cold energy.

"Prior Art and its Problems" As is well known, when phase transformation occurs from ice to water or from water to ice, 80 Cal/cm ³ of heat is exchanged. Compared to the same volume of water, it can hold 80 times more heat capacity by utilizing its latent heat, making it possible to construct an extremely effective cold storage device. Conventionally, this has been done by freezing the cooling water on the surface of the cooling pipe and utilizing the latent heat of the ice during melting, which is called an ice bank. As the ice temperature increases, the conduction of heat to the frozen surface gradually decreases, and the rate of ice formation decreases significantly. Also, since freezing, melting, and cooling occur through the frozen layer,
Heat conduction is poor, and in order to promote this, it is necessary to increase the temperature gradient between the cooling water and the surface of the cooling pipe. The operating efficiency of a refrigerator at such a cooling temperature is extremely low. Furthermore, if the ice on the surface of the cooling pipe becomes bridged with each other, the surface of the ice is further reduced, the heat exchange rate for supplying cold water is reduced, and the ability to follow changes in load is also reduced. Furthermore, it is difficult to detect and measure the thickness of ice that grows on the cooling pipe surface, and it is difficult to improve the accuracy of the measurement, and it is difficult to say that there will be no damage to the cooling pipes or heat storage tank due to excessive freezing in the event of a malfunction in operation control.

As for other methods, there are concerns about capsule breakage caused by volume expansion during the phase transformation of ice from water, heat exchange between the capsule and cooling water during operation, and freezing of ice inside the capsule. Its use has been hindered due to unclear aspects such as the state of ice, operation control and protection of the cold heat storage device in relation to the amount of ice formed.

As is well known, utilizing the latent heat during phase transformation of ice rather than water is essential for cold storage heat storage devices, but at the same time, since the density of ice during phase transformation is 0.917, its covered volume is 1.0905, and the volume Expansion takes place. The compressive force of ice is extremely large, so when it freezes, an ordinary container cannot withstand it, and if it is unable to follow it, it will break. This is the cause of the bursting accidents that occur due to malfunctions in the control of water coolers for producing chilled water, as mentioned above. Even if the elastic proportionality limit of the capsule is larger than the volumetric expansion of ice, if freezing and melting are repeated, melted water will enter the melted area and freeze.
Eventually, the elastic proportionality limit of the container will be exceeded and the container will be destroyed.

"Technical Means for Solving the Problems" The present invention is a cold storage heat storage device using capsules, which was developed in view of these points. In the cold heat storage device that utilizes ice latent heat of water sealed in the capsule, the capsule is formed of an elastic capsule filled with deaerated water, and the relative specific gravity of at least one of the capsules to the brine liquid is and a means for detecting the specific gravity of the brine liquid relative to water, a capsule weight value is calculated based on the outputs from both of the detection means, and the operation of the cold storage heat tank is determined based on a change in the weight value. We propose a cold storage heat storage device configured to perform control.

Next, the present invention will be schematically explained.

It is desirable to use a vacuum pump to remove not only air bubbles but also air and other gases dissolved in the water that is filled into the capsule.The capsule must be completely filled with such water and then sealed in the capsule. By doing so, it is possible to accurately measure the specific gravity when the water in the capsule changes to ice, and the ice changes to water.

Further, the capsule may have any shape or polyhedron, and the shape with the smallest surface area is a spherical capsule, which is the most economical shape in terms of the ratio of its volume to internal volume. Taking this as an example, the linear expansion of the material of the spherical capsule structure is ³ √1.0905
There is no problem if it is equal to or greater than = 1.0293.

Furthermore, if the material of the capsule is an elastic material with good thermal conductivity, the capsule will be a metal capsule, but there is no problem if it is made of resin, which does not harden or change in quality at low temperatures. Capsules made in this way have elasticity, so during the process of repeated freezing and melting, there is no possibility that melted water may enter the melted area from elsewhere. This is not possible since the entire surface is filled with water. That is, no matter how many times the capsule freezes and melts, the capsule cannot expand more than the volume expansion due to phase transformation, so the capsule cannot break.

Since the capsule is constructed as described above, it is possible to directly measure the volume change, that is, the change in the outer diameter of the capsule during the freezing and melting process, but since the capsule is immersed in liquid brine and heat exchange takes place, , means for detecting the relative specific gravity of a representative standard capsule to liquid brine of the capsule during immersion;
Means for detecting the specific gravity of the brine liquid with respect to water is provided, and based on the outputs from both of the detection means, the capsule weight value, more specifically, the specific gravity of water (ice) in the capsule is calculated, and from the specific gravity, the capsule weight is calculated. The above-described drawbacks of the prior art can be overcome by determining the melting or freezing state of the ice and controlling the operation of the cold storage heat tank in accordance with the determined state.

"Embodiments" Hereinafter, embodiments of the present invention will be described in detail by way of example based on the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. Not too much.

An example of this capsule specific gravity measuring device is shown in FIG. Figure 2 is an example of the virtue curve of freezing and melting ice.
The figure shows a control system diagram of the cold storage heat storage device.

In Fig. 1, 1 is a spherical ice detection capsule filled with water and sealed, 2 is liquid brine, 3 is a capsule weight balance spring, 4 is an iron core for spring index detection, 5 is an excitation wire ring, and 6 is a wire ring conductor. This is a spherical capsule specific gravity measuring device. In Fig. 2, a is a curve showing changes in the amount of ice formed and melted V in the capsule with respect to the cooling elapsed time T of the liquid brine, and b is a curve showing changes in the temperature t inside the capsule and the elapsed cooling time T with respect to a. This is an example of an actual measuring device using a capsule specific gravity measuring device.

Figure a clearly shows the state in which the amount of ice forming inside the capsule increases with respect to the elapsed cooling time T, and also clearly shows the state in which the ice melts inside the capsule when cooling water is used. b is the change in temperature t inside the capsule while state a is progressing. The s point is a manifestation of the supercooling phenomenon of water that occurs inside the capsule during freezing. In Fig. 3, 7 is a spherical float for measuring the specific gravity of brine, 8 is a detection section using a spherical float, 9 is a conducting wire for the brine specific gravity detection section, 10 is a specific gravity detection calculation device, 11 is a cold storage heat tank, and 12 is an elastic body for cold storage heat. A spherical capsule, 13 a cooling device, 14 a liquid brine cooling pipe, 15 an air cooler, and 16 a liquid brine circulation pump.

Next, we will discuss this operation.

In the cold storage heat tank 11, there is a freezing detection spherical capsule 1,
Brine specific gravity measurement Spherical floats 7 are immersed in liquid brine 2, and the floating and sinking of these floats is detected by the detection unit 3,
4, 5, and 8 are outputted as shown in the characteristic curve in Figure 2, which is input to the specific gravity detection calculation device 10, and from the calculation result, all of the ice frozen in the elastic spherical capsule 12 for cold storage heat storage in the cold storage heat storage tank 11 is determined. The amount of ice is detected. In the heat storage tank 1 having such a control system, the liquid brine 2 is cooled to below zero degrees through the brine cooling pipe 14 in the cooling device 13, and the water filled in the elastic spherical capsule 12 is frozen. While the water is frozen, its temperature remains at zero degrees, and the latent heat is stored in the capsule in a frozen state, and the amount of frozen water is detected by the specific gravity detection device 10. Control such as starting and stopping the operation of the cooling device 13 is performed using this output. For example, extremely economical operation can be easily performed by freezing the air cooler 15 in advance based on the required amount of cold storage heat in the air cooler 15 by estimating the next day's weather conditions.

The above describes an example in which the total amount of ice is calculated and detected using a standard capsule, which is a typical ice detection spherical capsule.
Needless to say, measurements can be taken.

"Effects" Since the present invention is a cold heat storage device that utilizes the latent heat of water filled in an elastic capsule as described above,
The amount of cold storage heat is extremely large, and even if the capsule is used, it will not be damaged when it freezes.
The surface where ice melts and the frozen surface are the same, the temperature gradient may be small, and therefore there is no need to reduce the cooling temperature significantly, the cooling system has good operating efficiency, and it is easy to detect ice formation and melting. Since hysteresis does not occur, the detection accuracy of ice formation is high, and operation control is easy. Also, from a protection standpoint, it is a basic fail-safe type and can be operated safely. It has various effects such as

[Brief explanation of drawings]

Figure 1 is an example of a capsule specific gravity measurement device, Figure 2 is an example of ice formation and ice melting characteristic curves, and Figure 3 is a control system diagram of a cold storage heat storage device. 1: Ice detection spherical capsule, 2: Liquid brine, 7: Spherical float for measuring brine specific gravity, 10: Specific gravity detection calculation device, 11: Cold storage heat tank, 12: Elastic spherical capsule for cold storage heat, 13: Cooling device, 14: Liquid brine cooling pipe, 15: Air cooler, 16: Liquid brine circulation pump.

Claims (1)

[Scope of Claims] 1. A cold storage heat storage device that utilizes ice latent heat of the water sealed in the capsules by immersing a group of capsules filled with water in a brine solution, wherein the capsules are degassed and filled with water. formed of capsules, at least one of the capsules and the float located in the brine solution are each connected to a detection section of a specific gravity detection calculation device located above the brine solution via a connecting member, and from the detection section Relative specific gravity to brine solution,
Detecting the specific gravity of the brine liquid relative to water, calculating the weighed value of the capsule with the specific gravity detection calculation device based on the detected value, and controlling the cooling operation of the cold storage heat tank in response to a change in the weighed value. A cold storage heat device characterized by being configured to perform the following functions.