JP2005044707A - Circulation structure of heating medium for storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulation structure of a heating medium for a storage tank capable of responding to a complex system using the heating medium at every site, through lowering of pressure loss at a normal operation. <P>SOLUTION: In the circulation structure 1 of the heating medium for the storage tank provided with a storage tank part 3 storing a storage medium (purified water) 2, and a heating medium circulation channel 6 formed at least either an outside or an inside of a wall face 4 of the storage tank part 3 where a heating medium exchanging heat with the storage medium 2 is circulated, the heating medium is made circulated at the normal operation in a bypass channel 7 with a smaller circulation resistance than the heating medium circulation channel 6, and is made circulated at an abnormal operation in the heating medium circulation channel 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a distribution structure of a storage tank heat medium having a function of thawing a frozen storage medium by circulating the heat medium.

  Since the fuel cell functions in a wet state, the fuel cell must sufficiently humidify the supplied hydrogen and oxygen. For this reason, a vehicle equipped with a hydrogen storage type fuel cell system needs to have a storage tank for storing pure water for humidifying hydrogen and oxygen. In addition, when using this fuel cell system in a cold region, the pure water in the storage tank may freeze, so it is necessary to use a storage tank with a thawing and thawing function for thawing the frozen pure water. (For example, refer to Patent Document 1).

The storage tank includes a hollow portion for storing a stored item, a flow path for a heat medium disposed in the hollow portion at equal intervals and parallel to the longitudinal axis of the container, and a heat medium supply port communicating with the flow path. The heat medium discharge port and a plurality of double-wall structures that freeze and thaw the stored material through the flow path through which the heat medium flows. Moreover, in order to improve heat transfer performance, the flow path through which the heat medium flows is set to be divided into three or more flow path systems.
JP-A-5-154467 (page 3, FIG. 1)

  However, in the configuration described above, the flow path through which the heat medium flows is set to be divided into three or more flow path systems, so that the heat medium flow path is complicated to repeat branching and merging many times in the storage unit. It has a simple structure. For this reason, in the circulation system of the heat medium, there is a problem that the flow of the uniform heat medium is impaired as a whole, the heat exchange capacity is lowered, and further, it becomes a pressure loss element of the flow path of the heat medium. In addition, since the heat medium passes through this complicated flow path even during the thawing operation (unsteady operation) or the steady operation of the storage medium, in the above-described configuration, the heat medium is distributed to every part. There was a problem that it was unsuitable for what constitutes a complex system to be used.

  Also, if the length of the flow path is increased by branching the flow path through which the heat medium flows or by increasing the number of bendings, etc., the pressure loss of the increased portion increases and the load on the pump that flows the heat medium increases. Therefore, there was a problem that the fuel consumption of the system deteriorated.

  Furthermore, since the flow resistance increases not only by increasing the flow velocity but also by reducing the inner diameter, the use of a large number of thin tubes inevitably increases the flow resistance and increases the pressure loss, but the heat transfer requires a larger surface area. Because it is advantageous, it cannot be said that it is generally good to use a thin tube, which has been a problem.

  The present invention has been made to solve the above problems, and is formed on a storage tank portion in which a storage medium is stored, and at least one of an outer side or an inner side of a wall surface of the storage tank unit, and the storage medium A storage tank heat medium distribution structure having a heat medium flow path through which a heat medium to exchange heat flows, and during steady operation, the heat medium is circulated in a state of less flow resistance than the heat medium flow path; The gist of the present invention is to provide a distribution mechanism for distributing the heat medium to the heat medium flow passage during the unsteady operation.

  According to the present invention, inflow of the heat medium is easy, flow resistance is small, pump power loss is reduced, and heat transfer efficiency of the heat exchanger is improved. Thus, since the pressure loss at the time of steady operation reduces, the load of the circulation apparatus which circulates a heat medium can be suppressed. In addition, it is possible to provide a heat transfer medium distribution structure for a storage tank that can be applied to a complex system in which the heat transfer medium is used in all parts.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view for explaining an embodiment of a storage tank heat medium flow structure according to the present invention.

  The storage tank heat medium distribution structure 1 described above includes a storage tank section 3 in which pure water (storage medium) 2 is stored, a heat medium flow passage 6 in which a heat medium that exchanges heat with the pure water 2 flows, A circulation mechanism is provided that causes the heat medium to flow with less flow resistance than the heat medium flow passage 6 during steady operation, and causes the heat medium to flow through the heat medium flow passage during non-steady operation. The upper surface of the storage tank portion 3 is a lid portion 3a. In addition, an inlet 6a and an outlet 6b of a heat medium flow passage 6 through which a heat medium flows are connected to the outer wall portion 5, and a passage formed by the wall surface 4 of the storage tank portion 3 is a heat medium flow passage. 6 communicates. In this passage, a heat medium circulated from a circulation device (not shown) circulates in a direction indicated by an arrow. Further, the heat medium is also distributed to the bypass flow path 7 side from the inlet 6 a of the heat medium flow path 6. The bypass flow path 7 is provided so that the inflow port 6a and the outflow port 6b side may be connected. An adjustment valve 9 for adjusting the flow rate of the heat medium is disposed in the bypass flow path 7, and the heat medium flowing into the bypass path 7 passes through the adjustment valve 9 from the adjustment valve inlet 6 c shown in FIG. The adjustment valve inlet 6d returns to the heat medium passage 6 through the outlet 6b.

  Inside the storage tank unit 3, a temperature sensing unit 8 shown in FIG. The temperature sensing unit 8 includes a cylindrical body 8 a that is hollow inside, an inclusion 8 b that is enclosed in the cylindrical body 8 a and whose volume changes according to temperature, and a narrow tube 10 that communicates with the regulating valve 9. ing. A change in pressure inside the temperature sensing unit 8 is transmitted to the regulating valve 9 by the thin tube 10. The regulating valve 9 has a pressure chamber 9a, and has a structure separated from the bypass channel 7 by a diaphragm 9b. Also, a so-called valve portion 9c such as a needle or a spool is attached to the diaphragm 9b, and the valve portion 9c is fixed to the pressure chamber 9a side by a spring 9d. The position of the valve portion 9c is determined from the balance between the internal pressure of the pressure chamber 9a and the pressure of the heat medium, and the force of the spring 9d. In this embodiment, the freezing point temperature of the pure water 2 is set to a point where the balance of the force changes. In addition, when the pressure of the pressure chamber 9a changes, the pressure 9a changes the position of the valve part 9c via the diaphragm 9b. The change in the position of the valve portion 9c is the opening degree.

  The enclosure 8b inside the cylindrical body 8a is filled with, for example, HCFC (hydrochlorofluorocarbon) gas. Since this gas has a characteristic that the evaporation temperature can be determined by temperature and pressure, if it is set to evaporate at the freezing point temperature of the pure water 2, this temperature becomes the operating point of the adjusting valve 9. Acting force can be generated.

  This storage tank heat medium distribution structure 1 is used in a fuel cell system 11 as shown in FIG. In this case, a coolant (coolant) for cooling the fuel cell stack is used as the heat medium, and is circulated in the heat medium flow passage 6 by the coolant pump 12. The pure water 2 stored in the storage tank unit 3 is circulated and supplied to the fuel cell 13 via the pipe 15 by the pure water pump 14. The pure water 2 supplied to the fuel cell 13 is used for humidifying hydrogen and oxygen necessary for power generation. The pure water 2 is used as humidifying water for the fuel cell 7 from the viewpoint of insulation.

  Next, the operation of the storage tank heat medium distribution structure 1 configured as described above will be described.

  When the ambient temperature around the storage tank heat medium distribution structure 1 decreases and the temperature of the pure water 2 in the storage tank section 3 in which the pure water 2 is stored falls below 0 degrees Celsius, the pure water 2 starts to freeze. . When the pure water 2 is frozen, the tank 3 is filled with ice blocks.

  Here, since the storage medium is pure water 2, if the valve portion 9c is set to open at 0 degrees Celsius or more, the cylinder of the temperature sensing portion 8 when the pure water 2 is frozen (during unsteady operation). The volume of the enclosure 8b inside 8a decreases and the pressure inside the cylinder 8a falls. This pressure is transmitted to the pressure chamber 9a of the regulating valve 9 through the thin tube 10, and acts so that the pressure in the pressure chamber 9a decreases. Since the regulating valve 9 is closed in this way, the heat medium does not flow through the bypass path 7, and the entire amount of the heat medium flows through the passage formed by the wall surface 4 of the storage tank unit 3, thereby promoting the thawing of the pure water 2. Acting in the direction of

  Further, during steady operation, the volume of the enclosure 8b inside the cylinder 8a of the temperature sensing unit 8 increases and the pressure inside the cylinder 8a rises. This pressure is transmitted to the pressure chamber 9 a of the regulating valve 9 through the thin tube 10. And since the regulating valve 9 opens, a heat medium flows into the bypass path 7. For this reason, the heat medium which flows to the storage tank part 3 side decreases, and the pressure loss of the heat medium acts in the direction of decreasing.

  According to the present embodiment, since it is not necessary to circulate the coolant except when the pure water 2 is frozen during the unsteady operation, the coolant also passes through the bypass path 7 during the steady operation, so that the pressure loss is reduced. Fuel consumption is improved.

  Further, in the conventional method, when the length of the heat medium flow path 6 is increased by branching the heat medium flow path 6 into a plurality of parts or increasing the number of bendings, the pressure loss in this portion increases, so the coolant pump The fuel consumption of the fuel cell system deteriorated. However, in this embodiment, the pressure loss is reduced by the coolant passing through the bypass path 7 except during freezing, so that the pump load can be increased in the minimum necessary time. For this reason, the defrosting performance is improved and the defrosting time can be shortened. Therefore, since the start-up time is shortened even during freezing, a fuel cell system in which deterioration of fuel consumption is minimized can be provided.

  As described above, when the storage tank heat medium flow structure 1 is used in a fuel cell system, the electrical conductivity of pure water must be kept low. For this reason, it is preferable to use a material that does not affect the electrical conductivity during storage of pure water for the wall surface 4 and the temperature sensing unit 8 of the storage tank unit 3. As such a material, it is preferable to use, for example, a stainless material, especially SUS316L or SUS310S. Further, when a stainless steel material is not used, the same effect can be obtained by applying a resin coating to the liquid contact surface.

  Further, in the present embodiment, the heat medium flow passage 6 is provided outside the storage tank unit 3, but it may be configured to be provided in the storage tank unit 3.

  Furthermore, the temperature is detected by an electrical signal using a thermistor or the like that electrically detects the temperature instead of the temperature sensing unit 8 and an electromagnetic solenoid valve instead of the adjusting valve 9, and the temperature change becomes a set value or more. In this case, the electromagnetic solenoid valve may be energized with an electric signal to open and close the valve.

It is sectional drawing explaining embodiment of the distribution structure of the thermal medium for storage tanks concerning this invention. It is sectional drawing which shows a temperature sensing part and an adjustment valve. It is a block diagram which shows the example of the pure water tank which provided the refrigerant | coolant flow path for fuel cell cooling in the heat-transfer part.

Explanation of symbols

1 Distribution structure of storage tank heat medium 2 Pure water (storage medium)
DESCRIPTION OF SYMBOLS 3 Storage tank part 4 Wall surface 5 Outer wall part 6 Heat-medium flow path 6a inflow port 6b outflow port 7 Bypass flow path 8 Temperature sensing part 9 Control valve 10 Narrow tube

Claims (11)

A storage tank section in which a storage medium is stored;
A storage tank heat medium flow structure having a heat medium flow passage formed on at least one of the outer side or the inner side of the wall surface of the storage tank part and through which the heat medium that exchanges heat with the storage medium flows,
A storage tank comprising: a circulation mechanism that causes the heat medium to flow with less flow resistance than the heat medium flow path during steady operation, and causes the heat medium to flow to the heat medium flow path during non-steady operation. Distribution structure for industrial heat medium.   The flow mechanism includes a bypass flow path that connects an inlet side and an outlet side of the heat medium flow passage so that the heat medium flows more as the temperature of the storage medium is higher. 2. The distribution structure of the heat medium for the storage tank according to 1.   When the storage medium in the storage tank unit is frozen by the circulation mechanism, all of the heat medium is caused to flow into the heat medium flow path, and the thawing of the storage medium in the storage tank unit is completed and at least the heat 3. The storage tank heat medium flow structure according to claim 2, wherein a part of the medium flows into the bypass flow path. The bypass control mechanism includes:
A temperature sensing part for detecting the temperature of the storage medium;
An adjustment valve arranged on the bypass flow path to adjust the flow rate of the heat medium flowing through the bypass flow path by changing an opening degree based on a detection result of the temperature sensing unit. The distribution structure of the heat medium for a storage tank according to claim 2 or claim 3. The temperature sensing part is
A cylindrical body having a hollow inside;
A gas or a mixture of a gas and a liquid that is sealed inside the cylinder and changes in volume with temperature,
A narrow tube communicating with the regulating valve,
The distribution structure of the heat medium for the storage tank according to claim 4, wherein a change in pressure inside the temperature sensing unit is transmitted to the adjustment valve by the thin tube to change the opening of the adjustment valve.   The temperature sensing unit detects the temperature of the storage medium by an electric signal, and the adjustment valve is opened and closed by the electric signal detected when the temperature of the storage medium becomes a set value or more. 5. A distribution structure of the heat medium for the storage tank according to 4.   The distribution structure of the storage tank heat medium according to any one of claims 1 to 6, wherein the storage tank section stores pure water for a fuel cell system.   8. The storage tank heat medium distribution structure according to claim 7, wherein the heat medium also serves as a cooling medium of the fuel cell.   The storage tank heat according to claim 7 or 8, wherein the wall surface of the storage tank section and the temperature sensing section are made of a material that does not change the electrical conductivity of pure water. Medium distribution structure.   The distribution structure of the heat medium for the storage tank according to claim 9, wherein a stainless material is used for the wall surface of the storage tank section and the temperature sensing section.   The distribution structure of the heat medium for the storage tank according to claim 9 or 10, wherein a resin coating is applied to a wall surface of the storage tank section and the temperature sensing section.

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