JPH08152162A - Internal melting type ice storage tank - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to provide an internal melting type ice heat storage tank that enables improvement of the ice heat extraction rate and simple measurement of ice quantity. A water tank 7, a heat transfer tube 8 for forming heat storage ice immersed in the water tank 7, and a support member 9 for supporting the heat transfer tube 8 in the water tank 7 are provided, and a heat transfer medium is evaporated by a refrigerator or a heat pump. The heat transfer medium is circulated between the machine 6 and the heat transfer tube 8, and the heat transfer medium whose temperature has dropped due to heat exchange in the evaporator 6 of the refrigerator or heat pump and the water 15 in the water tank 7 are exchanged.
In the internal melting type ice heat storage tank 2 that forms ice on the outer peripheral portion of the support member 9, the support member 9 is made of metal, is provided at a predetermined interval with respect to the heat transfer tube 8, and is provided with an air diffuser tube 18 that discharges air below the heat transfer tube 8. A blower 19 for sending air to the air diffuser 18 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal melting type ice heat storage tank attached to a refrigerator and a heat pump.

[0002]

2. Description of the Related Art In recent years, in air conditioners for building air conditioning and district cooling, operating costs are reduced by effective use of late-night power, power consumption is leveled during midnight and daytime, and initial investment in air conditioners is reduced. Ice storage tanks are increasingly being installed for the purpose of such as.

A conventional air conditioner having an ice heat storage tank will be described with reference to FIG. FIG. 9 is a schematic configuration diagram showing one of conventionally known air conditioners, which includes a refrigerator 101 and an ice heat storage tank 102. The refrigerator 101 is the compressor 10
3, the condenser 104, the expansion valve 105, and the evaporator 106 form a closed loop, and the refrigerant circulates while performing a refrigeration cycle in this closed loop. In addition, the ice heat storage tank 10
2 is a water tank 107, a heat transfer tube 108 for forming heat storage ice,
A support 109 for supporting the heat transfer tube 108 in the water tank 107 is provided. As shown in FIG. 9, the heat transfer tube 8 is formed by alternately repeating a U-shaped curve and a straight line portion in the water tank 107 to elongate the heat transfer tube 8 that can be immersed in the water tank 7, thereby enabling a heat transfer area. The structure is made to be as large as possible. In addition, the heat transfer tube 108 includes the evaporator 106,
A closed loop is formed by being connected to the pipelines 110 and 111 connected to the pump 112. In such a closed loop, brine containing ethylene glycol or the like as a main component is reflowably filled so as to maintain a liquid state. In addition, the heat transfer pipe 10 is provided by the switching valve 113 provided in the pipe line 111.
8 and the evaporator 106, instead of the circulation through the pipeline 111a, the circulation through the pipeline 111b, the heat exchanger 114 and the return to the pipeline 111 can be switched.

When cold energy is stored in the ice heat storage tank 102, the switching valve 113 is used to circulate through the pipe 111a. Here, the refrigerant of the refrigerator 101 circulates to perform a refrigerating cycle, and the refrigerant evaporates in the evaporator 106 to take heat of evaporation, so that the brine that exchanges heat with the refrigerant is taken away. The brine cooled by the evaporator 106 is guided by the pump 112 to the heat transfer tube 108 via the conduit 110,
Here, heat is exchanged with the water in the water tank 107, and then it is returned to the evaporator 106 via the pipe line 111 and the pipe line 111a. By circulating the brine in such a closed loop, ice is formed on the outer peripheral portion of the heat transfer tube 108.

On the other hand, when the cold heat is taken out from the ice heat storage tank 102, the operation of the refrigerator 101 is stopped and the switching valve 113 is used.
To switch to the circulation through the pipeline 111b. As a result, the large amount of heat of melting taken from the surroundings when the ice on the outer periphery of the heat transfer tube 108 is melted is used to cool the brine flowing through the heat transfer tube 108, and the cooled brine is passed through the pipe 111b to the heat exchanger 114. Fluidize. This heat exchanger 114 enables cooling. In other words, by forming ice using midnight power, accumulating cold heat, and using this ice heat storage for cooling during the daytime, the power consumption can be leveled during the day and night.

[0006] The ice heat storage tank 102 described above, that is, the ice heat storage tank that causes the brine to flow through the heat transfer tube 108 when the ice heat is used to indirectly melt the ice on the outer peripheral portion of the heat transfer tube 108 from the inside of the heat transfer tube 108. 102 is generally defined as an internal fusion type. As a prior art in which a device for circulating water is provided in the above-mentioned internal melting type ice heat storage tank 102, Japanese Patent Laid-Open No. 6-1
There is No. 1158.

[0007]

The conventional internal melting type ice heat storage tank 102 attached to the refrigerator 101 and the like introduced above has the following inconveniences.

As shown in FIG. 10, an internal melting type ice heat storage tank 10
In No. 2, the brine is caused to flow in the heat transfer tube 108 so that the ice 11
In order to melt 5a, the ice 115a is melted from the periphery of the heat transfer tube 8 into a cylindrical shape. Since water 115b stays between the cylindrical ice 115a and the heat transfer tube 108 in a substantially sealed state, the heat transfer tube 108 and the ice 115a are different from each other in the surrounding water 115b.
The heat will be transferred only by natural convection. For this reason, the amount of heat transfer per hour is relatively small, and the extraction speed and temperature of the ice heat storage are restricted. This is because in natural convection, the thermal boundary layer becomes thicker and the heat transfer coefficient becomes smaller than in forced convection. Further, the water 115 around the outer periphery of the ice 115a is almost stationary, and the heat transfer tube 108 and the ice 115a
The fact that there is almost no convection and mixing with the water 115b that exists between the ice and water is also a factor that limits the extraction rate and temperature of the ice heat storage. It should be noted that the prior art of JP-A-6-
As in No. 11158, even if the water 115 in the ice heat storage tank 102 is circulated, almost no water 115b existing in a substantially sealed state can be circulated between the heat transfer tube 108 and the ice 115a. The effect of increasing the heat transfer coefficient with 115a is small.

Also, the amount of ice 115a can be known by measuring the change in the water level in the ice heat storage tank 102 from the difference in the specific volume between the water 115 and ice 115a. Since the water 115b existing between the ice 115a and the ice 115a is substantially sealed and does not flow freely with the water 115 outside the ice 115a, even if the ice 115a melts from the periphery of the heat transfer tube 108, the inside of the ice 115a Bubbles are generated in the water, and the change in the amount of ice 115a does not directly appear in the change in the water level. For this reason, it becomes difficult to calculate the amount of ice due to changes in the water level that can be easily measured.

By the way, the above-mentioned internal melting type ice heat storage tank 102 is used.
There is also an external fusion type. In FIG. 9, instead of the switching valve 113 and the pipe line 111b, the ice heat storage tank 102 is shown.
The two water pipes X and Y (shown by phantom lines in FIG. 9) are opened in the water tank 107, and the water 115 outside the ice 115 a formed around the heat transfer tube 108 is circulated to thereby remove the ice 115 a. It melts and takes out ice heat. According to this external melting type ice heat storage tank, since the ice 115a on the outer peripheral portion of the heat transfer tube 108 is directly melted by the water 115 in the water tank 107, the above-mentioned disadvantage, that is, the melted water 115b (see FIG. 10) is sealed. Although there is no inconvenience such as the restriction of the ice heat extraction rate resulting from the above, the so-called bridging phenomenon in which the ice 115a formed on the outer peripheral portion of the heat transfer tube 108 during ice making is connected as shown in FIG. As a result, a zone 115c where the water 115 does not flow is generated. Therefore, in this zone 115c, even if the water 115 in the water tank 107 is circulated while exchanging heat, the water 115 does not melt, and the ice heat extraction rate is significantly restricted. Further, in order to prevent the bridging phenomenon from occurring, the ice filling rate (IPF), which is the rate at which the water 115 in the ice heat storage tank 102 undergoes the phase transition to the ice 115a, is limited, and the ice heat storage capacity becomes small. From this point of view, in the internal melting type ice heat storage tank 102, it is desired to solve the above-mentioned inconvenience.

The present invention has been made to solve the above-mentioned conventional inconvenience, and an object of the present invention is to provide an internal melting type ice heat storage tank capable of improving an ice heat extraction rate and the like and easily measuring the amount of ice. To do.

[0012]

In order to achieve the above-mentioned object, an internal melting type ice heat storage tank of the present invention comprises (1) a water tank, a heat transfer tube for forming heat storage ice immersed in the water tank, and A support member for supporting the heat transfer tube in the water tank is provided, the heat transfer medium is circulated between the evaporator of the refrigerator or heat pump and the heat transfer tube, and the temperature is lowered by heat exchange in the evaporator of the refrigerator or heat pump. In the internal melting type ice heat storage tank in which ice is formed on the outer peripheral portion of the heat transfer tube by heat exchange between the heat transfer medium and the water in the water tank, the supporting member is made of metal and has a predetermined interval with respect to the heat transfer tube. It is provided in.

(2) As described in claim 2, the distance between the support member and the heat transfer tube may be 10 to 50 times the outer diameter of the heat transfer tube.

(3) As described in claim 3, metal studs may be provided so as to protrude from the outer peripheral portion of the heat transfer tube.

(4) As described in claim 4, metal fins may be provided so as to protrude from the outer peripheral portion of the heat transfer tube.

(5) As described in claim 5, it is preferable to provide a diffusing tube for discharging air below the heat transfer tube and a blower for feeding air to the diffusing tube.

(6) As described in claim 6, one end of the suction pipe whose one end is opened above the water tank, one end of which is a discharge pipe opened below the water tank, and the upper part of the inside of the water tank through the suction pipe. It is preferable to include a water circulation device including a water pump that sucks water and discharges the sucked water to the lower portion inside the water tank through the discharge pipe.

[0018]

According to the internal melting type ice heat storage tank of the present invention having the above-mentioned structure, the following effects can be obtained.

(1) Due to the fact that the support member is made of metal and has good heat conduction, the ice on the outer peripheral portion of the heat transfer tube is melted at the same time when the ice is thawed, and at the same time, a predetermined amount of heat is transferred to the heat transfer tube. Ice around the metal support member provided at intervals also melts, and in the prior art, there is a hole in the cylindrical ice around the support member,
The substantially sealed state of water existing inside the cylindrical ice is released. By adjusting the distance between the support members, it is possible to promote the flow of water existing between the heat transfer tube and the cylindrical ice and the water existing on the outer peripheral portion of the cylindrical ice by natural convection. Therefore, it is possible to promote the thinning of the temperature boundary layer around the heat transfer tube, and it is possible to improve the ice heat extraction speed and lower the ice heat extraction temperature.

Further, as described above, a flow path is formed between the water existing between the heat transfer tube and the cylindrical ice and the water existing on the outer peripheral portion of the cylindrical ice, and the water existing inside the cylindrical ice is formed. Since the substantially closed state has been released, air bubbles are not enclosed inside the cylindrical ice, and the relationship between the amount of ice and the water level in the water tank is linear. Therefore, the amount of ice can be accurately measured by measuring the change in water level.

(2) According to the internal melting type ice heat storage tank of the second aspect, the action of the above (1) is effectively exhibited. The shorter the distance between the support member and the heat transfer tube, the more holes that can be made in the cylindrical ice, which promotes the flow of water inside the cylindrical ice and the water that exists outside the ice, and the ice heat extraction speed, etc. However, since it is economically unfavorable because the material cost, the processing cost, etc. increase, the outer diameter of the heat transfer tube is set as the interval between the supporting members that effectively exhibits the action described in (1) above. The upper limit is 50 times. Further, if the supporting members are too close to each other, ice is formed so as to wrap the supporting members during ice making, so that when the ice is thawed, water is confined to the inside of the ice, and the action described in the above (1) is exerted. It will not be possible. From this viewpoint, the lower limit of the distance between the support member and the heat transfer tube is 10 times the outer diameter of the heat transfer tube.

(3) According to the inner melting type ice heat storage tank of the third aspect, the inner melting type ice storage tank of the first or second aspect is provided because the metal stud is provided on the outer peripheral portion of the heat transfer tube. It is possible to make holes in the cylindrical ice more easily and positively than in the structure in which the metal support member is provided for the heat transfer tube as in the heat storage tank. Therefore, the flow of water existing between the heat transfer tube and the cylindrical ice and the water existing in the outer peripheral portion of the cylindrical ice due to natural convection can be further promoted, and the ice heat extraction rate can be improved. And, it is possible to further promote the decrease of the ice heat storage temperature. Further, since the release of the substantially sealed state of the water existing inside the cylindrical ice becomes more complete, the accuracy of measuring the amount of ice from the change in the water level increases.

(4) According to the internal melting type ice heat storage tank of the fourth aspect, since the fins made of metal are projected on the outer peripheral portion of the heat transfer tube, the outer peripheral portion of the heat transfer tube is formed into a cylindrical shape. A crevice can be made along the fin on the side of the ice. By providing this metal fin on the side surface of the heat transfer tube in a spiral shape or a ring shape, a linear crack can be made on the side surface of the cylindrical ice, and between the heat transfer tube and the cylindrical ice. The flow of the existing water and the water existing in the outer peripheral portion of the cylindrical ice due to natural convection can be further promoted. Therefore, it is possible to further improve the above-mentioned speed of ice heat extraction, and further improve the accuracy of measuring the amount of ice from a drop in the temperature of ice heat extraction or a change in the water level.

(5) According to the internal melting type ice heat storage tank of claim 5, since the air diffuser pipe to which the air is sent from the blower is provided below the heat transfer pipe and the air is discharged, the water in the ice heat storage tank is discharged. Can be forcibly convected and stirred. The forced convection in the ice heat storage tank uses the holes formed in the cylindrical ice as a flow path to forcibly generate convection in the water existing between the heat transfer tube and the cylindrical ice. . For this reason, the temperature boundary layer around the heat transfer tube becomes thin and the heat transfer coefficient is significantly improved, and the cold water existing on the outer surface of the cylindrical ice flows in and mixes, so that the ice heat extraction rate can be significantly improved. it can. Further, the ice heat extraction temperature can be lowered to near 0 ° C. which is the melting temperature.

(6) According to the internal melting type ice heat storage tank of the sixth aspect, a suction pipe having one end opened above the water tank, a discharge pipe having one end opened below the water tank, and the suction pipe. 5. The internal melting type ice heat storage system according to claim 4, further comprising a water circulation device including a water pump for sucking water in the upper part of the water tank through the water and discharging the sucked water to the lower part of the water tank through the discharge pipe. Like the air diffuser and blower equipped in the tank, it is possible to forcibly convect not only the water inside the ice storage tank but also the water existing between the heat transfer tube and the cylindrical ice. Therefore, the above (5)
The same effect as described can be exhibited.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an air conditioner equipped with an internal melting type ice heat storage tank of the present invention will be described below with reference to the drawings.

(1) Air Conditioning Apparatus Equipped with Inner Melting Ice Heat Storage Tank of the Present Invention FIG. 1 is a schematic block diagram of an air conditioning apparatus equipped with the inner melting ice storage tank of the present invention. The air conditioner shown in FIG. 1 is different from the conventional air conditioner shown in FIG. 9 in that the ice heat storage tank 2 is used in place of the ice heat storage tank 102.
The point that the refrigerant circulates while performing the refrigeration cycle in the closed loop including the compressor 103, the relationship of the ice heat storage tank 102 to the refrigerator 101, the role thereof, and the like are substantially the same. The same number (the last two digits are the same) is given and the description is omitted.

The ice heat storage tank 2 includes a water tank 7, a heat transfer tube 8 for forming heat storage ice, and a support member 9. The support member 9 is a metal columnar body that is erected upward from the bottom surface of the water tank 7, and supports the heat transfer tube 8 by attaching the heat transfer tube 8 to a recess provided on the side surface of the columnar body. ing.
Further, the heat transfer tube 8 has a straight line portion and a U-shaped curved portion which are alternately repeated in a horizontal direction in a substantially same plane to increase a heat transfer area for the water 15 in the water tank 7. As described above, a large number of the heat transfer tubes 8 having a meandering shape which are stretched in the horizontal direction are arranged side by side in the direction perpendicular to the plane of the drawing on the substantially same plane, and are joined to the headers 16 and 17 to join. This header 16,
Reference numeral 17 is a single conduit extending in the direction perpendicular to the plane of the drawing. Also, the headers 16 and 17 are
It joins with 11, forms a closed loop with the evaporator 6, and circulates brine by the pump 12. The description so far is similar to the conventional technique shown in FIG. 9, but in the above-described conventional technique, the heat transfer tube 8 has been simplified for the sake of easy understanding, and therefore the description will be given here. added.

In this embodiment, the metal support member 9 is provided at a predetermined distance from the heat transfer tube 8. When the ice heat storage is taken out, as shown in FIG. 2, the ice around the heat transfer tube 8 is thawed from the periphery of the heat transfer tube 8 to become water 15b, and the cylindrical ice 15a remains on the outer peripheral portion of the heat transfer tube 8. At the same time, since the supporting member 9 is made of metal and has good heat conduction, the supporting member 9 is also thawed around the supporting member 9 and a hole 20 is formed in the cylindrical ice 15a. Therefore, the water 15b inside the cylindrical ice 15a and the water 15 outside
A channel is formed in the water, and the water 15b existing inside the cylindrical ice 15a as in the prior art is released from the substantially hermeticity. Therefore, unlike the case where the water 15b is in a sealed state, bubbles are generated inside the cylindrical ice 15a during melting due to the difference in specific volume between ice and water, and the water level and the ice amount are not linked. The amount of the cylindrical ice 15a directly appears in the change in the water level, and the amount of ice can be easily known by measuring the change in the water level.
Further, by providing the support members 9 at predetermined intervals as described above and forming a flow path between the water 15b inside the cylindrical ice 15a and the water 15 outside, the arrow (phantom line) shown in FIG. Such natural convection can be generated to improve the heat transfer coefficient to the heat transfer tube.

Further, in the present embodiment, as shown in FIG. 1, an air diffuser 18 is provided below the heat transfer tube 8 in the ice heat storage tank 2, and a blower 19 for sending air to the air diffuser 18 is provided. The air diffuser 18 is a conduit having fine holes for discharging air. By discharging air from the bottom of the water tank 7 by this air diffuser, the water 15 in the water tank 7 can be forcibly convected and stirred. This forced convection extends to the water 15b existing inside the cylindrical ice 15a shown in FIG.
Forced convection as shown by the arrow (phantom line) in FIG. 2 can be caused. Therefore, the temperature boundary layer near the heat transfer tube 8 is thinned, and the heat transfer coefficient is significantly improved. Also, water tank 7
The fact that the water 15 in the inside can be close to 0 ° C. which is the melting temperature of the ice 15 a also promotes the reduction of the cold heat extraction temperature.

It should be noted that the shorter the interval at which the support member 9 is provided with respect to the heat transfer tube 8, the more the flow paths between the water inside the cylindrical ice and the water outside the cylindrical ice and the convection can be promoted. Although it can be improved, the outer diameter of the heat transfer tube 8 is 30
The effect can be effectively exhibited even at a distance interval of up to 50 times. However, if the distance between the support member 9 and the heat transfer tube 8 is too short,
When ice is made, a situation occurs in which ice is formed so as to wrap the support member 9, and conversely, when ice is thawed, a sealed water layer is generated inside the ice. Therefore, the distance between the support member 9 and the heat transfer tube 8 must be 10 times or more the outer diameter of the heat transfer tube 8. Further, the support member 9 is preferably iron, copper, or aluminum. Further, the stirring effect by providing the air diffuser and discharging the air has a higher stirring effect per unit energy than the stirring effect by circulating water described later.

(2) Embodiment in which a metal stud is provided on the outer peripheral portion of the heat transfer tube It is also possible to project a metal stud 21 on the outer peripheral portion of the heat transfer tube 8. In this case, the heat transfer tube 8 is provided. FIG. 3 (a) is a cross-sectional view showing the ice-melting state of the periphery, and FIG. 3 (b) is a vertical cross-sectional view. Since this stud 21 is made of metal and has good heat conduction, a hole 22 is formed in the peripheral portion of the stud 21 in the ice 15a that melts from the periphery of the heat transfer tube 8 and remains in a cylindrical shape at the time of thawing. This hole 22 is used for water 15 outside the cylindrical ice 15a.
And the water 15b in the inside of the support member 9 serve as a flow path, which has the same effect as the hole 20 in the peripheral portion of the support member 9 described above. It is not preferable to add the above-mentioned support member 9 to the heat transfer tube 8 because it causes an increase in material cost, processing cost and the like from the economical aspect, but the stud 22 of this embodiment has a relatively simple structure. , It can be expanded while considering economy. The stud 22 of this embodiment
Is iron, similar to the support member 9 of the above-mentioned embodiment (1).
Copper, aluminum and the like are preferable. Further, the length of the stud 22 needs to be longer than the thickness of ice during heat storage.

(3) Embodiment in which metal fins are provided on the outer peripheral portion of the heat transfer tube It is also possible to provide metal fins 23 on the outer peripheral portion of the heat transfer tube 8. FIG. 4A is a perspective view of the fin 23 having a ring shape, and FIG. 4 is a perspective view of the fin 23 having a spiral shape.
It shows in (b). Since the fins 23 are also made of metal and have good heat conduction, a crack is formed along the fins 23 in the ice 15a that remains in the cylindrical shape when the ice is thawed. Similar to the hole 22 formed by the stud 21 shown in FIG. 3, this rupture serves as a flow path between the water 15b inside the cylindrical ice 15a and the water 15 outside, and the water 15b inside the cylindrical ice 15a is substantially abbreviated. The hermeticity is released, and the same operation as the support member 9 of the above-described embodiment (1) is achieved. Like the stud 22, the fin 23 has a relatively simple structure and is excellent in economy. Also fin 2
The shape of 3 is not limited to the shape shown in FIG. 4, and, for example, a structure provided in parallel with the heat transfer tube 8 or the like is also possible. The material is iron,
Copper, aluminum, etc. are preferable, and the thickness is the same as that of the stud 22 of the above-described embodiment (2) in that it must be thicker than the thickness of ice generated during heat storage.

(4) Embodiment with Water Circulation Device As shown in FIG. 5, a suction pipe 24 having one end opened above the water tank 7 and a discharge pipe 25 having one end opened below the water tank 7.
And a water pump 26 that sucks the water 15 in the upper part of the water tank 7 through the suction pipe 24 and discharges the sucked water 15 into the lower part of the water tank 7 through the discharge pipe 25. It is also possible. The above embodiment (1)
Similarly to the air diffuser 18 and the blower 19 equipped on the heat transfer tube 8, the support member 9, the stud 21, and the fin 23 cooperate with the holes 20 and 22 formed in the cylindrical ice 15a to form the heat transfer tube 8. Water 15 existing between the cylindrical ice 15a
It is possible to force convection up to b (see FIGS. 2 and 3). Therefore, the temperature boundary layer around the heat transfer tube 8 can be thinned to improve heat transfer. Therefore, the ice heat extraction temperature can be lowered and the ice heat extraction speed can be improved.

(5) Details of the above-mentioned embodiment, examination of effects, and operating method FIG. 6 shows a detailed embodiment of the internal melting type ice heat storage tank 2 according to the present invention. The heat transfer tube 8 was a JIS-25A steel tube and constituted a heat transfer tube block 28. This heat transfer tube block 28 is shown in FIG.
As shown in, the bending interval A is 3.5 m and the pitch C is
Has a meandering length of 120 mm and consists of a meandering tube bent 15 times, and one end of each of the two meandering tubes is joined by a U vent 27, and the other ends are connected to a brine inlet side header 16 and a brine outlet side header 17, respectively. It has a structure. Also,
The distance D between the two meandering tubes was 110 mm. The support member 9 of the heat transfer tube block 28 was a columnar steel material, and was installed so that the distance B between the straight portions of the heat transfer tube 8 was 1.25 m. The curved portion of the heat transfer tube 8 has a length of 60 mm and a diameter of 5 mm.
The steel stud 21 of No. 2 was projected. The water tank 7 (see FIG. 1) had a depth of 2.2 m, a width of 7.6 m, and a depth of 2.8 m, and six heat transfer tube blocks 28 were immersed therein.

FIG. 7 shows the relationship between the heat transfer coefficient and the melting degree of ice in this embodiment. The vertical axis is a logarithmic scale and the heat transfer coefficient (Kcal / m).
² h ° C.) and the horizontal axis shows the melting degree of ice. Here, ● indicates the case where air is not discharged by the blower 19 (see FIG. 1), and ○ indicates the air discharge amount per unit area of 0.6 m ³ /
m ² · h, and ▲ is the case where the air discharge amount per unit area is 1.1 m ³ / m ² · h. As is clear from the figure, the heat transfer coefficient is remarkably improved by increasing the discharge amount of air and increasing the forced convection of water in the water tank. This is because, out of the cylindrical ice that has melted, the holes formed around the support member are used as a flow path, and water existing inside the cylindrical ice can be forcibly convected and stirred. However, in this experiment, heat transfer tubes without studs were used.

FIG. 8 shows the relationship between the amount of ice calculated by calculating the heat balance from the flow rate of brine and the change in enthalpy at the entrance and exit of the heat transfer tube and the amount of ice calculated from the change in the water level in the present embodiment. The amount of ice obtained from the balance is shown, and the horizontal axis shows the amount of ice obtained from the water level. As is clear from the figure, the ice amounts obtained by the two methods are almost equal, and it can be seen that the ice amount can be accurately measured from the change in the water level. Here, the unit of the ice amount shown on both axes of the table of FIG. 8 is the weight per 1 m of the heat transfer tube 8.

When cold heat is stored by the above-mentioned ice heat storage tank,
Brine cooled to −10 ° C. is circulated to the heat transfer tube by the evaporator of the refrigerator, and ice is produced on the outer peripheral portion of the heat transfer tube until the average thickness is 40 mm and the ice filling rate is 75% (IPF). The operation cost can be reduced by performing the work of storing the cold energy in 10 hours from 10 pm to 8:00 am of the nighttime electricity charge application time. Further, when the cold energy stored in this way is taken out from the ice heat storage tank, the brine is circulated between the heat transfer tube and the heat exchanger, and the brine heated to 5 to 10 ° C. due to the cooling load in the heat exchanger, 0-5 in ice heat storage tank
By cooling to ° C. Also, in the initial stage of taking out cold heat, air is not discharged through the air diffuser. This is because in the initial stage of taking out cold heat, ice is in contact with the outer peripheral portion of the heat transfer tube, and therefore it is not necessary to stir the outer peripheral portion of the heat transfer tube.
When the cold heat is taken out and ice starts to melt at the outer periphery of the heat transfer tube and the periphery of the studs, etc., when air flow is created between the heat transfer tube and the ice remaining in the cylindrical shape, air is blown by the air diffuser. Discharge. This forces convection in the flow path,
The heat transfer rate can be improved.

[0039]

EFFECTS OF THE INVENTION As is apparent from the above description, the internal melting type ice heat storage tank according to the present invention has the following effects.

(1) When the ice is thawed, according to the prior art, the cylindrical ice has a hole around the metal supporting member having good heat conduction, and the water existing between the heat transfer tube and the cylindrical ice and the cylinder are It is possible to promote flow due to natural convection with water existing on the outer peripheral portion of the ice cube. Therefore, it is possible to promote the thinning of the temperature boundary layer around the heat transfer tube, and it is possible to improve the ice heat extraction speed and lower the ice heat extraction temperature. Therefore,
It is possible to rapidly cool a predetermined place.

As described above, a flow path is formed between the water existing between the heat transfer tube and the cylindrical ice and the water existing on the outer peripheral portion of the cylindrical ice, and the water existing inside the cylindrical ice is formed. Since the substantially closed state of is released, the amount of ice can be accurately measured by measuring the change in water level. In order to manage the cooling capacity of the ice heat storage tank, it is necessary to grasp the heat storage amount of the ice heat storage tank, that is, the amount of ice, but according to the ice heat storage tank of the present invention, this can be easily done by measuring the change of the water level. Can be achieved.

(2) According to the internal melting type ice heat storage tank of the second aspect, the effect described in the above (1) is effectively exhibited. As the distance between the support member and the heat transfer tube is shorter, the ice storage heat extraction speed and the like can be improved, but the material cost, the processing cost, and the like increase, which is economically unfavorable. Therefore, the effect described in (1) above is obtained. The upper limit is 50 times the outer diameter of the heat transfer tube as the distance between the supporting members that is effectively exhibited. Further, if the supporting members are too close to each other, ice is formed so as to wrap the supporting members during ice making, so that when the ice is thawed, water is confined to the inside of the ice, and the action described in the above (1) is exerted. It will not be possible. From this viewpoint, the lower limit of the distance between the support member and the heat transfer tube is 10 times the outer diameter of the heat transfer tube.

(3) According to the inner melting type ice heat storage tank of the third aspect, since the metal studs are provided on the outer peripheral portion of the heat transfer tube, the inner melting type ice heat storage tank of the first aspect is provided. As described above, it is possible to easily and positively make a hole in the cylindrical ice as compared with the structure in which the metal support member is provided for the heat transfer tube. Therefore, the flow of water existing between the heat transfer tube and the cylindrical ice and the water existing in the outer peripheral portion of the cylindrical ice due to natural convection can be further promoted, and the ice heat extraction rate can be improved. And further contributes to the drop in the temperature for extracting ice heat. Further, since the release of the substantially sealed state of the water existing inside the cylindrical ice becomes more complete, the accuracy of measuring the amount of ice from the change in the water level increases.

(4) According to the internal melting type ice heat storage tank of the fourth aspect, since the fins made of metal are projected on the outer peripheral portion of the heat transfer tube, the cylindrical outer peripheral portion of the heat transfer tube is formed. A crevice can be made along the fin on the side of the ice. This rift has the same effect as the hole formed by the stud projecting in the ice heat storage tank according to the above-mentioned claim 2, and it is possible to improve the ice heat extraction speed and decrease the ice heat extraction temperature or change the water level. It further contributes to the accuracy of measuring the amount of ice. In addition, by providing the metal fins in a spiral shape or a ring shape on the side surface of the heat transfer tube, it is possible to make a linear crevice on the side surface of the cylindrical ice, and the heat transfer tube and the cylindrical ice can be separated from each other. It is possible to increase the number of flow paths between the water existing between the water and the water existing on the outer peripheral portion of the cylindrical ice. Furthermore, since the metal fins are provided so as to project from the heat transfer tube, there is an effect of increasing the surface area of the heat transfer tube, which is also a factor for improving the ice heat extraction rate.

(5) According to the internal melting type ice heat storage tank of claim 5, the air diffuser pipe to which the air is sent from the blower is provided below the heat transfer pipe, and the air is discharged so that the water in the ice heat storage tank is discharged. Not only can forced convection be generated in the water, but the holes and crevices formed in the cylindrical ice as described above are used as flow paths, and the water existing between the heat transfer tube and the cylindrical ice is forcibly forced. Cause convection. Therefore, the temperature boundary layer around the heat transfer tube becomes thin, and the heat transfer coefficient is remarkably improved. As a result, it is possible to remarkably improve the ice heat extraction rate. Further, the ice heat extraction temperature can be lowered to near 0 ° C. which is the melting temperature.

(6) According to the internal melting type ice heat storage tank of the sixth aspect, the suction pipe having one end opened above the water tank, the discharge pipe having one end opened below the water tank, and the suction pipe are provided. 5. The internal melting type ice heat storage tank according to claim 4, comprising a water circulation device comprising a water pump for sucking water in the upper part of the water tank and discharging the sucked water to the lower part in the water tank through the discharge pipe. Like the air diffuser and blower equipped, it is possible to forcibly convect not only the water inside the ice storage tank but also the water existing between the heat transfer tube and the cylindrical ice. Therefore, the same action as the action described in (4) above can be exhibited.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a refrigerator including an internal melting type ice heat storage tank according to an embodiment of the present invention (when a supporting member and a diffuser are provided at predetermined intervals).

FIG. 2 is a cross-sectional view showing a defrosted state around a heat transfer tube in the internal melting type ice heat storage tank of FIG.

FIG. 3 is a cross-sectional view showing a defrosting state around a heat transfer tube in an internal melting type ice heat storage tank according to an embodiment of the present invention (when a stud is projecting); Figure (b) is a vertical sectional view.

FIG. 4 is a side view showing a heat transfer tube of an internal melting type ice heat storage tank according to an embodiment of the present invention (when fins are provided to project). However,
The figure (a) shows a ring-shaped fin and the figure (b) shows a spiral fin.

FIG. 5 is a schematic configuration diagram showing an inner melting type ice heat storage tank according to an embodiment of the present invention (when a supporting member and a water circulating device are provided at predetermined intervals).

FIG. 6 shows a manufacturing process of a heat transfer tube in an internal melting type ice heat storage tank according to an embodiment of the present invention (when a supporting member and a stud are provided at predetermined intervals), and FIG. Then, FIG. 3B is a side view.

FIG. 7 is a diagram showing a relationship between a heat transfer coefficient and a melting degree in an internal melting type ice heat storage tank according to an embodiment of the present invention (when a supporting member and a diffuser are provided at predetermined intervals). However, the vertical axis indicating the heat transfer coefficient is on a logarithmic scale.

FIG. 8: Obtained from the heat balance calculation of the refrigerant flowing back into the ice making tube in the internal melting type ice heat storage tank according to the embodiment of the present invention (when the supporting member at a predetermined interval, the stud, and the air diffuser are provided). It is a figure which shows the relationship between the amount of ices and the amount of ices calculated from the change of a water level.

FIG. 9 is a schematic configuration diagram showing a refrigerator provided with a conventional internal melting type ice heat storage tank.

10A and 10B show a state of thawing around a heat transfer tube in the internal melting type ice heat storage tank of FIG. 9, where FIG. 10A is a horizontal sectional view and FIG. 10B is a vertical sectional view.

FIG. 11 is a vertical cross-sectional view showing an ice making state around the heat transfer tube of the outer melting type ice heat storage tank.

[Explanation of symbols]

 1 Refrigerator 2 Ice heat storage tank 3 Compressor 4 Condenser 5 Expansion valve 6 Evaporator 7 Water tank 8 Heat transfer tube 9 Support member 12 Pump 13 Switching valve 14 Heat exchanger 15 Water 16/17 Header 18 Air diffuser tube 19 Blower 21 Stud 23 Fins 24 suction pipes 25 discharge pipes 26 water pumps 27 U vents 28 heat transfer tube blocks

Claims (6)

[Claims] 1. A water tank, a heat transfer tube for forming heat storage ice immersed in the water tank, and a support member for supporting the heat transfer tube in the water tank, wherein the heat transfer medium is a refrigerator or a heat pump evaporator. Between the heat transfer tube and the heat transfer tube, and heat is exchanged between the heat transfer medium whose temperature has dropped due to heat exchange in the evaporator of the refrigerator or heat pump and the water in the water tank to form ice on the outer circumference of the heat transfer tube. In the internal melting type ice heat storage tank, the supporting member is made of metal and is provided at a predetermined interval with respect to the heat transfer tube. 2. The internal melting type ice heat storage tank according to claim 1, wherein the distance between the support member and the heat transfer tube is 10 to 50 times the outer diameter of the heat transfer tube. 3. The internal melting type ice heat storage tank according to claim 1, wherein a metal stud is provided on the outer peripheral portion of the heat transfer tube. 4. The internal melting type ice heat storage tank according to claim 1, 2 or 3, wherein metal fins are provided so as to protrude from the outer peripheral portion of said heat transfer tube. 5. An air diffuser for discharging air below the heat transfer tube, and a blower for sending air to the air diffuser.
The internal melting type ice heat storage tank according to any one of 1. 6. A suction pipe whose one end is opened above the water tank, a discharge pipe whose one end is opened below the water tank, and water in the upper part of the water tank is sucked through the suction pipe. The internal melting type ice heat storage tank according to any one of claims 1 to 4, further comprising a water circulation device including a water pump that discharges the water through the discharge pipe to a lower portion inside the water tank.