JP2566079B2 - Ice heat 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 used for air-conditioning a building or the like, and for producing and processing foods that are cooled and stored at ice temperatures.

[0002]

2. Description of the Related Art FIG. 2 is a system diagram showing a conventional ice heat storage device. Reference numeral 1 denotes a refrigerating apparatus, which includes a compressor 2, a condenser 3, a pressure reducing device 4, and an evaporator 5 as main components.
The evaporator 5 is composed of a plurality of heat transfer tubes, each having a plurality of refrigerant circuits and water circuits. 6 is a heat storage tank equipped with ice and water,
7 is an aqueous solution to which a certain salt is added to stabilize supercooling, 8 is ice produced, 9 is a subcooling releasing device for producing ice from the supercooled aqueous solution, and 10 is water to the evaporator. The ice removing device 11 that removes ice from the ice is a water supply pump. In addition, the cold water in the heat storage tank 6 is supplied by another pump 1
3 is sent to the load heat exchanger. Note that there is a prior application of the inventors for certain salts to be added to stabilize the supercooling of ice, and several types of chemicals are disclosed here. From the viewpoint, the most practical additive is dipotassium hydrogen phosphate (K2HPO4).
The optimum addition concentration depends on the quality of tap water used, but is about 0.1 to 0.3%.
Range. Further, regarding the supercooling releasing device 9, there is a prior application of the inventor, in which a cold finger is provided in the air and ice fine crystals can be supplied to the liquid surface of the heat storage tank 6 from there. It is characterized by non-contact. Since the supercooled aqueous solution and the cold finger are not in contact with each other, it is possible to avoid many inconveniences as compared with the contact type supercooling canceling device 9, for example, generated ice is not stacked on the supercooling canceling device 9. You can do it, but its utility remains the same.

Next, the operation of the ice heat storage device will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 2 of the refrigeration system 1 exchanges heat with the condenser 3 to become a high-pressure liquid refrigerant. Next, it is adiabatically expanded by the decompression device 4 to become low temperature and low pressure saturated steam. Heat is exchanged in the evaporator 5, and the temperature is several degrees C below the freezing point (minus 2
The aqueous solution 7 supercooled to about (° C.) is guided by a pipe 12 and is provided by a supercooling releasing device 9 provided in the upper part of the heat storage tank 6 in the vicinity of the outlet of the pipe 12, that is, a low-temperature generating device with a small capacity of about −5 ° C. The supercooled state is broken, and a small piece of ice 8 corresponding to the amount of heat of supercooling is generated, and flows into the heat storage tank 6 together with the remaining aqueous solution 7. The ice 8 floats above the aqueous solution 7 having a freezing point temperature in the heat storage tank 6. The aqueous solution 7 in the lower part of the heat storage tank 6 passes through the ice removing device 10 and is sent to the refrigerating device 1 by the pump 11 to form a refrigerating cycle. In this way, ice pieces are continuously generated in the heat storage tank 6, and the occupancy rate of ice increases. In this heat storage operation, inexpensive midnight power is used, and this cold heat is used during cooling in the daytime. Therefore, an aqueous solution having a freezing point temperature is sent to the heat exchanger 14 by the pump 13, and the heated aqueous solution is stored in the heat storage tank 6 Then, the latent heat is utilized by melting the ice 8.

[0004]

The conventional ice heat storage device is constructed as described above, and it is to prevent freezing in the evaporator 5 in order to obtain continuous production of ice. That is, the supercooling phenomenon is very unstable, and even if a stabilizer is mixed, there is a certain region (about -15 ° C), and even if the temperature is below the freezing point, the evaporator 5 has a plurality of heat transfer tubes. Since it was composed of, it was easily affected by variations in the refrigerant circuit and water circuit. Further, if the temperature of a certain heat transfer tube is lowered due to variations and the supercooling is destroyed and freezes, the other heat transfer tubes also start freezing at once, and the entire evaporator may be frozen. In particular, when there are multiple water circuits, there is a branch of the water piping, etc., so there is a risk of collision due to the flow and breakage of subcooling leading to freezing.If partial freezing occurs, the heat transfer coefficient of the heat transfer tube And the performance of the evaporator 5 of the refrigerating apparatus is lowered, the evaporation temperature is lowered, and the freezing is rapidly expanded. Further, if iron rust is generated and mixed in the circulation circuit, or if ice nuclei crystals in the heat storage tank 5 pass through the ice removing device 10 and are mixed, they are deposited on the uneven portion of the inner pipe and further surface There was a risk that the roughness would increase and the inside of the evaporator 5 would freeze at once. Further, in order to eliminate the freezing of the evaporator 5, it is necessary to keep the temperature of the inflowing aqueous solution high. Further, if the suction temperature approaches the freezing point temperature, it becomes easier to suck more ice crystal nuclei, and it is necessary to design the suction temperature to be higher and the outlet temperature to be lower. For this reason
It was difficult to avoid the tendency of the supercooling stability of the circulating aqueous solution to decrease daily. Therefore, at the same time as removing iron rust, dust, and ice crystal nuclei in the circulation circuit, the structure of the plurality of heat transfer tubes of the evaporator 5 is also set on the refrigeration unit side so that the subcooling is not broken in the evaporator 5. The refrigerant circuit and the water circuit needed to be improved. Further, an evaporator which requires stable supercooling of the aqueous solution in the evaporator 5 and does not break is required. For this reason, as for ice generation due to supercooling, it is an excellent evaporator that maintains the stability of the refrigeration system and does not destroy supercooling even at minus several degrees, reducing the effects of dust and ice crystal nuclei in the circulation circuit. Was absolutely necessary.

The present invention has been made to solve the above-mentioned problems, and by making the refrigerating device stable, it is possible to continuously generate ice and to operate stably for a long period of time. The purpose is to obtain an ice heat storage device.

[0006]

In order to effectively achieve the above-mentioned object, the present invention has the following structure. That is, a refrigerating device including a compressor, a condenser, a decompressor, an evaporator, and the like, and a subcooling releasing device provided in a circulation circuit of a kind of salt aqueous solution supercooled by the refrigerating device, A heat storage tank for storing the ice and the supercooled water, and an ice heat storage apparatus having a circuit for circulating the heat storage tank and the evaporator in the refrigerating apparatus, wherein the evaporator has a plurality of double-tube structures. It consists of heat transfer tubes, water or supercooled water flows in the inner tube, and refrigerant flows in the inner tube / outer tube.
A plurality of water flow passages of the inner pipe are connected in series, and refrigerant flow passages of the inner pipe / outer pipe are connected in parallel.

[0007]

As described above, since the water flow passages of the inner pipe of the evaporator are connected in series and the refrigerant flow passages of the inner pipe / outer pipe are connected in parallel, the variation in the temperature of the outlet of the aqueous solution is eliminated and the refrigerant circuit side Since the pressure drop is reduced, freezing in the evaporator due to ice formation is prevented, stability of supercooling is improved, and reliability of the refrigeration system is also improved.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1, 3 and 4, FIG. 3 is a vertical cross-sectional view of the evaporator 5 according to one embodiment of the present invention, and FIG. 4 is a Y-Y horizontal cross-sectional view of the evaporator 5 shown in FIG. The evaporator 5 is composed of the following elements. Reference numeral 16 denotes an outer pipe, which is provided with a refrigerant inlet portion 16a at one end side and a refrigerant outlet portion 16b at the other end side, and is directed from the inner wall of the pipe toward the center between the refrigerant inlet portion 16a and the refrigerant outlet portion 16b. It has a plurality of heat transfer fins 16c protruding radially. Reference numeral 17 denotes an inner tube inserted into the outer tube 16, the outer surface of which is a heat transfer fin portion 16c of the outer tube 17.
It adheres to the inner edge of the. The refrigerant flow passage 16d separated from the heat transfer fin portion 16c by such a structure has, for example, 12 chambers. By using at least one heat transfer tube 15 shown in FIG. 3, the evaporator 5 shown in FIG.
Is configured. In this embodiment, three heat transfer tubes are used. 18
a is an aqueous solution inlet connection port, 18b is an aqueous solution outlet connection port, and 18c, 18d, and 18e are water pipes A, B, and C, and the water pipe A is the outlet side of the lower heat transfer tube 15 and the middle stage inlet side, The water pipe B is connected in series to the outlet side of the middle heat transfer pipe 15 and the inlet side of the upper heat transfer pipe 15, and the water pipe C is connected to the outlet side of the upper heat transfer pipe 15 and the outlet connection port in series. Water pipe A,
B and C have the same diameter and the same roughness as the inner tube of the heat transfer tube 15. Further, the water pipes A, B, and C are configured with an R bend of 4 times or more the inner pipe diameter in order to prevent the supercooling from being destroyed by the turbulent flow or collision of the flowing aqueous solution. As a result, even if iron rust or ice nuclei in the heat storage tank 5 pass through the ice removing device and enter the circulation circuit, there is no uneven portion and it is hard to deposit on the inner pipe and freezes in the evaporator 5. Fear can be prevented. Also,
The refrigerant inlet portion 16a and the refrigerant outlet portion 16b on the other end side are connected in parallel and the refrigerant is distributed. Therefore, the circulating aqueous solution enters through the inlet connection port 16a and the inner pipe 1
In the 7th part, it exchanges heat with the refrigerant and is cooled to be supercooled. The other configurations are the same as the conventional ones and will not be described.

Next, the operation will be described. When the aqueous solution in the heat storage tank 6 circulates and passes through the evaporator 5 of the refrigeration system 1 to start cooling, the temperature of the heat storage tank 6 gradually decreases, and the inlet temperature is about 1 degree and the outlet temperature evaporates. It is cooled in the vessel 5 to a supercooled state of several degrees below freezing (minus 2 ° C). Since the cooling capacity of the refrigerating apparatus 1 is determined by the condensation temperature and the evaporation temperature from the characteristics of the compressor 2, the pump 1 should be adjusted to meet the above temperature difference.
Determine the flow rate of 1. This supercooled aqueous solution breaks the supercooled state in the upper part of the heat storage tank 6 by the supercooling canceling device 9, and produces ice corresponding to the amount of supercooled heat. The aqueous solution that has not turned into ice is supplied to the evaporator 5 of the refrigerating apparatus 1 by the pump 11 through the ice removing apparatus 9 or the ice furnace passing apparatus 10. Ice 8 accumulates in the heat storage tank 6 while floating in the aqueous solution.

FIGS. 5 and 6 are views showing the cooling states of the conventional evaporator 5 and the evaporator 5 of the present embodiment. FIG. 5 is a conventional diagram,
FIG. 6 shows this embodiment. The conventional diagram in which the water circuit also has multiple branches is easily affected by uneven distribution of the refrigerant and dispersion of the aqueous solution. As a result, the supercooling outlet temperature is minus the average temperature minus 2 degrees as shown in the figure. 1
It becomes minus 2 degrees and minus 3 degrees. This variation has a great influence on the supercooling temperature, and since there is a branch portion of the water pipe section, there is a risk of collision due to the flow, breaking the subcooling, and freezing. In FIG. 6 of the present embodiment, the water pipes of the three heat transfer tubes are connected in series, and the temperature of each heat transfer tube is lowered sequentially, so that the above-mentioned problems do not occur and the subcooling temperature is reliably reduced. It will be twice. The effect of non-uniform flow distribution on the refrigerant side is small, and the pressure loss is small and the same. In addition, the flow paths of the aqueous solution have the same diameter and are configured by gentle bending R so that turbulent flow and collision do not occur, and there is no risk of subcooling breaking. In this way, freezing is prevented and stable operation of supercooling continues to produce ice.

[0011]

As described above, according to the present invention, in order to prevent the possibility of freezing in the evaporator 5 of the refrigerating device which makes the supercooling of water unstable, the evaporator is composed of a plurality of heat transfer tubes. Double pipe type structure, water or supercooled water flows in the inner pipe, the refrigerant flows in the inner pipe / outer pipe, and the refrigerant flow passage of the inner pipe / outer pipe is divided into a plurality of chambers. Since a plurality of water flow passages are connected in series and the refrigerant flow passages of the inner pipe / outer pipe are connected in parallel, the aqueous solution outlet temperature is unlikely to be affected by the unevenness of the refrigerant and the variation in the distribution of the aqueous solution. Since the pressure drop on the side is reduced, it is possible to prevent freezing in the evaporator during ice formation, improve the stability of supercooling, and improve the reliability of the refrigeration system. This allows
This has the effect of improving the stability of supercooling and ensuring stable operation of the ice heat storage device for a long period of time.

[Brief description of drawings]

FIG. 1 is a system diagram showing a refrigerating apparatus according to this embodiment.

FIG. 2 is a system diagram of a conventional ice heat storage device.

FIG. 3 is a vertical sectional view of a heat transfer tube of an evaporator according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view taken along the line YY of FIG.

FIG. 5 is an explanatory diagram showing a relationship between a refrigerant temperature and a supercooling temperature of a conventional evaporator.

FIG. 6 is an explanatory diagram showing the relationship between the refrigerant temperature and the supercooling temperature of the evaporator according to the embodiment of the present invention.

[Explanation of symbols]

 1 Refrigerator 2 Compressor 3 Condenser 4 Pressure reducer 5 Evaporator 6 Heat storage tank 7 Aqueous solution 8 Ice 9 Supercooling release device 10 Ice removing device 11 Pump 12 Piping 13 Pump 14 Load heat exchanger 15 Heat transfer pipe 16 Outer pipe 17 Inside tube

Claims (1)

(57) [Claims] 1. A refrigeration apparatus including a compressor, a condenser, a decompression device, an evaporator, and the like, and a supercooling releasing device provided in a circulation circuit of a kind of salt aqueous solution supercooled by the refrigeration apparatus. And a heat storage tank for storing the generated ice and supercooled water, and an ice heat storage apparatus having a circuit for circulating the heat storage tank and the evaporator in the refrigerating apparatus, wherein the evaporator has a double-tube structure. It consists of multiple heat transfer tubes, and water or supercooled water flows in the inner tube and refrigerant flows in the inner tube / outer tube.
An ice heat storage device, wherein a plurality of water flow passages of the inner pipe are connected in series, and refrigerant flow passages of the inner pipe / outer pipe are connected in parallel.