JP2808900B2 - Ice storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice heat storage device,
For example, the present invention relates to air conditioners for buildings and the like, and products used for production and processing of foods cooled and refrigerated at ice temperature.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional ice heat storage device described in, for example, Japanese Patent Application No. 1-229519. In the figure, 1 is a refrigerator, a compressor 2, a condenser 3,
A first flow control valve 4 and an evaporator 5 are provided as main components. 6 is a heat storage tank for storing ice and water, 7 is an aqueous solution containing a potassium salt or a sodium salt added to stabilize supercooling, for example, potassium salt or sodium salt, 8 is ice suspended in the aqueous solution 7, and 9 is supercooling release. For example, it is an ice block of a predetermined size and provided near the outlet of the supercooled aqueous solution.
10 is a filter which is an ice removing means for filtering ice 8 in the aqueous solution 7, 11 is a circulation pump for circulating the aqueous solution 7, 1
2 is a water pipe that connects one side to the heat storage tank 6 and sequentially connects the filter 10, the circulation pump 11, and the evaporator 5 to form a circulation path that leads the aqueous solution 7 cooled by the evaporator 5 to the heat storage tank 6. It is. In addition, the aqueous solution 7 may use only water without adding additives.

Next, the operation will be described. The aqueous solution 7 is cooled to a few degrees below the freezing point by the evaporator 5 of the refrigerator 1 (about −2 ° C.)
Supercooled until The supercooled state of the aqueous solution 7 is broken by an ice block 9 having a predetermined size provided in the upper part of the heat storage tank 6 through the pipe 12, and becomes small pieces of ice 8 corresponding to the amount of supercooled heat. The ice 8 flows into the heat storage tank 6 together with the remaining aqueous solution 7 that has not become ice, and the aqueous solution 7 having a freezing point temperature in the heat storage tank 6.
Floating on top of The aqueous solution 7 at the lower part of the heat storage tank 6 passes through the filter 10 and is sent to the refrigerator 1 by the circulation pump 11 to form a cycle.

FIG. 6 is a pressure-enthalpy diagram showing the operation of the refrigerator 1. Graph A shows the saturation line, and graph B shows the operation of the refrigerator 1. The state of operation changes in the direction of the arrow. The refrigerator 1 is controlled by the first flow control valve 4 so that the refrigerant at the outlet of the condenser 3 becomes a saturated liquid (point C) and the refrigerant at the outlet of the evaporator 5 becomes saturated vapor (point D). The portion of the straight line E is a change in the evaporator 5.

[0005]

The conventional ice heat storage device is configured as described above, and ice 8 in the aqueous solution flows into the evaporator 5 of the refrigerator, and the ice becomes the nucleus to form the ice. In order to prevent it from being generated inside and destroying the device,
An ice filter 10 is provided in a water pipe 12 on the inlet side of the evaporator 5. However, this still has the following problems. (1) Ice crystals are as small as several tens μm to several hundred μm, and it is necessary to make the filter of the ice filter very fine in order to capture the ice. However, if the filter is made fine, the flow of circulating water will increase. The resistance increases and the power of the circulation pump increases. (2) Clogging of the filter of the filter occurs, and maintenance for clogging of the filter is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and prevents ice 8 in an aqueous solution from flowing into an evaporator 5 of a refrigerator, thereby achieving stable and efficient operation. It is an object of the present invention to obtain an ice thermal storage device that can perform the above.

[0007]

An ice heat storage device according to the present invention is constituted by sequentially connecting a compressor, a condenser, a first flow control valve, and an evaporator, wherein water or an additive is added to water. A refrigerator for supercooling the aqueous solution, a supercooling release unit for releasing the supercooled water or the aqueous solution by this refrigerator and generating ice, and storing the ice and supercooled water generated by the supercooling release unit. In a heat storage tank, a circulating pump that feeds and circulates water or an aqueous solution in the heat storage tank to an evaporator, and an ice heat storage device including a circulation path that connects these in order and circulates the water or the aqueous solution, a first flow control valve is provided. Heat exchanger provided between the evaporator and the second flow control valve provided between the evaporator and the heat exchanger, and the presence of ice in the water or aqueous solution fed from the heat storage tank to the evaporator Water or aqueous solution Heat exchanger from the thermal storage tank, and configured to circulate sequentially to the evaporator, the heat exchanger, the heat exchanger
Depending on the temperature of the water or aqueous solution at the entrance, the evaporator
Alternatively, it is operated as a condenser .

[0008]

The water or aqueous solution of the ice heat storage device according to the present invention is cooled to a supercooled state several degrees below freezing in the evaporator of the refrigerator. The supercooled aqueous solution is released from the supercooled state by the supercooled release means in the upper part of the heat storage tank, and generates ice corresponding to the amount of supercooled heat. The water or aqueous solution that did not become ice is sent from the heat storage tank to the heat exchanger of the refrigerator by a circulating pump, and exchanges heat with the refrigerant having a temperature higher than the temperature of the water or the aqueous solution (0 ° C. or higher). After being heated to about 0.5 ° C., it flows into the evaporator and is cooled. Ice accumulates in the heat storage tank while floating in water or an aqueous solution. As means for preventing ice in the water or the aqueous solution from flowing into the evaporator of the refrigerator, a heat exchanger and a second flow control valve are provided between the first flow control valve and the evaporator of the refrigerator. Detecting means for detecting the presence of ice in the water or the aqueous solution fed from the tank to the evaporator is provided so that the operation state of the heat exchanger can be controlled.

[0009]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an ice heat storage device according to one embodiment of the present invention. In the figure, 22 and 23 are a heat exchanger and a second flow control valve provided between the first flow control valve 4 and the evaporator 5. 24 and 25 are heat exchangers 22
A first temperature sensor and a second temperature sensor which are provided at an inlet and an outlet, respectively, for detecting the temperature of the aqueous solution. The presence of ice in the water or the aqueous solution fed from the heat storage tank 6 to the evaporator 5 can be detected by the temperature sensors 24 and 25.
Note that the other configuration is the same as the conventional one, and thus the description is omitted.

Next, the operation will be described. The operation of the circulation system of the aqueous solution is exactly the same as that of the conventional apparatus, and the operation of only the refrigerator 1 is different. Therefore, the operation of only the refrigerator 1 will be described. The refrigerator 1 has a first operation mode when the temperature of the aqueous solution detected by the first temperature sensor 24 provided at the inlet of the heat exchanger 22 is 0 ° C. or more, and the temperature of the aqueous solution is 0 ° C. There is a second operation mode in which the operation mode has been reached. Each operation mode will be described below.

The first operation mode is a first temperature sensor-2.
This operation is performed when the temperature of the aqueous solution in the pipe 12 detected in step 4 is 0 ° C. or higher. For example, this mode is set when the ice heat storage device is started. FIG. 2 is a pressure-enthalpy diagram showing the operation of the refrigerator in the first operation mode. In this mode, the second flow control valve 23 is fully opened, and the gas refrigerant discharged from the compressor 2 is cooled and liquefied by the condenser 3 and reduced to a low pressure by the first flow control valve 4. The low-pressure refrigerant flows into the heat exchanger 22 and the evaporator 5 sequentially. Here, the refrigerant exchanges heat with the aqueous solution to cool the aqueous solution, becomes a gas state, and is sucked into the compressor 2 again. That is, as shown in the section F of FIG. 2, the heat exchanger 22 operates as an evaporator and contributes to cooling of the aqueous solution. The water or the aqueous solution is cooled to several degrees below freezing by the heat exchanger 22 and the evaporator 5 and returns to the heat storage tank 6.

When the temperature of the aqueous solution is lowered by the operation in the first operation mode and ice nuclei enter the aqueous solution, a first temperature sensor provided at the aqueous solution inlet of the heat exchanger 22 is provided. At −24, it is detected that the temperature of the aqueous solution has reached 0 ° C. At this time, the second operation mode is set. FIG. 3 is a pressure-enthalpy diagram showing the operation of the refrigerator 1 in the second operation mode. In this mode, the second flow control valve 23 is throttled, and the heat exchanger 22 is operated as a condenser. Compressor 2
Is cooled and liquefied in the condenser 3 to become a saturated liquid. This liquid refrigerant is reduced in pressure to an intermediate pressure by the first flow control valve 4 and flows into the heat exchanger 22, where it exchanges heat with water or an aqueous solution and heats. This refrigerant is reduced in pressure to a low pressure by the second flow control valve 23, flows into the evaporator 5, cools the aqueous solution by exchanging heat with water or the aqueous solution, and is sucked into the compressor 2. At this time, the first flow control valve 4 is controlled so that the refrigerant at the outlet of the evaporator 5 is slightly overheated, and the second flow control valve 23 is controlled by the second temperature sensor 25 provided at the outlet of the heat exchanger 22.
The temperature of the aqueous solution detected is controlled so as to be about + 0.5 ° C. Therefore, in the second operation mode, the aqueous solution 7 at 0 ° C. sent from the heat storage tank 6 by the circulation pump 11 is sufficiently melted by the heat exchanger 22 so that the ice core is melted.
After being heated to about 0.5 ° C., it is cooled to a supercooled state by the evaporator 5 and returns to the heat storage tank 6.

With this configuration, the crystal nuclei 8 of ice do not flow into the evaporator 5 and are frozen, so that stable continuous operation can be performed. Furthermore, since the water or the aqueous solution is heated by the heat of the refrigerant of the refrigerator 1,
As the cooling capacity of the evaporator 5 increases, a filter is not required, the power of the circulation pump 11 can be reduced, and highly efficient operation can be performed.

Embodiment 2 FIG. In the first embodiment, in the first operation mode, the second flow control valve 23 is fully opened. However, in this embodiment, an on-off valve 30 is provided in parallel with the second flow control valve 23 as shown in FIG. In the operation mode 1, the on-off valve 3
0 may be controlled so that the on-off valve 30 is closed in the second operation mode. By providing the on-off valve 30, the pressure difference between before and after the second flow control valve 23 can be reduced.

In the above embodiment, the heat exchanger 22 is provided between the circulating pump 11 and the evaporator 5, but the heat exchanger 22 may be provided between the heat storage tank 6 and the circulating pump 11. effective.

In the above embodiment, the first flow control valve 4 is controlled in the second operation mode so that the refrigerant at the outlet of the evaporator 5 is slightly heated.
May be controlled so that the outlet refrigerant at the outlet is slightly supercooled.

In the above-described embodiment, the first flow control valve 4 is controlled so that the refrigerant at the outlet of the evaporator 5 is slightly heated in the second operation mode, and the second flow control valve 23 is connected to the heat exchanger 22.
In the above description, the control is performed such that the temperature of the aqueous solution detected by the second temperature sensor 25 provided at the outlet of the evaporator 5 is about + 0.5 ° C. Control the refrigerant to overheat slightly,
When the temperature of the aqueous solution detected by the second temperature sensor 25 provided at the outlet of the heat exchanger 22 is +
The temperature may be controlled to be about 0.5 ° C.

In the above embodiment, the first temperature sensor 24 is provided at the inlet of the heat exchanger 22. However, the core of the ice may be detected by detecting the amount of transmitted light or the like.

Further, in the above-described embodiment, the supercooling releasing means has been described as an ice block of a predetermined size provided near the outlet of the supercooled aqueous solution, but may be a metal plate-like material such as stainless steel.

[0020]

As described above, according to the present invention, a compressor, a condenser, a first flow control valve, and an evaporator are sequentially connected, and water or an aqueous solution obtained by adding an additive to water is used. A supercooling refrigerator, a supercooling release unit that releases supercooling of water or an aqueous solution supercooled by the refrigerator and generates ice, and a heat storage tank that stores the ice and supercooled water generated by the supercooling release unit. A circulating pump that feeds and circulates water or an aqueous solution in the heat storage tank to an evaporator, and an ice heat storage device that connects these in order and has a circulating path through which the water or the aqueous solution circulates; A heat exchanger provided between the heat exchangers, a second flow control valve provided between the evaporator and the heat exchanger, and detection for detecting the presence of ice in water or an aqueous solution fed from the heat storage tank to the evaporator. Equipped with a means to transfer water or aqueous solution from the heat storage tank Exchanger, and configured to circulate sequentially to the evaporator, a heat exchanger, in the heat exchanger inlet
Evaporator or condenser depending on the temperature of water or aqueous solution
By operating in the first operation mode,
Means that the heat exchanger operates as an evaporator and the water or water in the heat storage tank is
The solution can be cooled for efficient operation and the second
Operating mode, the heat exchanger is used as a condenser
To prevent ice nuclei from flowing into the evaporator
There is an effect that an ice heat storage device that can perform an inexpensive operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an ice heat storage device according to Embodiment 1 of the present invention.

FIG. 2 is a pressure-enthalpy diagram illustrating an operation of the refrigerator in a first operation mode according to the first embodiment of the present invention.

FIG. 3 is a pressure-enthalpy diagram illustrating an operation of the refrigerator in a second operation mode according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing an ice heat storage device according to Embodiment 2 of the present invention.

FIG. 5 is a configuration diagram showing a conventional ice heat storage device.

FIG. 6 is a pressure-enthalpy diagram showing the operation of the refrigerator of the conventional ice heat storage device.

[Description of Signs] 1 Refrigerator 2 Compressor 3 Condenser 4 First flow control valve 5 Evaporator 6 Heat storage tank 7 Aqueous solution 8 Ice 9 Subcooling release means 11 Circulation pump 22 Heat exchanger 23 Second flow control valve 24 Ice Detection means

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazunari Nakao 8-1-1 Tsukaguchi Honcho, Amagasaki City Mitsubishi Electric Corporation Central Research Laboratory (72) Inventor Shinichi Wakamoto 8-1-1 Tsukaguchi Honcho Amagasaki City No. Mitsubishi Electric Corporation Central Research Laboratory (56) References JP-A-4-222372 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F24F 5/00 102

Claims (1)

(57) [Claims] 1. A refrigerator configured to sequentially connect a compressor, a condenser, a first flow control valve, and an evaporator, and supercools water or an aqueous solution obtained by adding an additive to water. Supercooling release means for releasing supercooling of the cooled water or aqueous solution to generate ice, a heat storage tank for storing ice or supercooled water generated by the supercooling release means, and water or an aqueous solution in the heat storage tank. in the ice thermal storage apparatus including the evaporator feed to circulating pump for circulating the, as well as the circulation path connected to the water or aqueous solution is circulated them sequentially, the <br/> first flow control valve and the evaporator A heat exchanger provided therebetween, a second flow control valve provided between the evaporator and the heat exchanger,
And detecting means for detecting the presence of ice in the water or the aqueous solution fed from the heat storage tank to the evaporator, and circulating the water or the aqueous solution from the heat storage tank to the heat exchanger and the evaporator in this order. The heat exchanger is configured to
At the inlet of the heat exchanger.
An ice heat storage device that operates as an evaporator or a condenser according to a temperature .