JP2005294197A - Liquid tank and liquid temperature control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pure water tank of a fuel cell system in which thawing time of the frozen pure water in the tank is shortened, and refreezing is prevented, and furthermore, excessive power consumption is reduced. <P>SOLUTION: The pure water tank 1 comprises a heating heater 4 for thawing the pure water 3 stored in the tank 2 and a jacket 5 which is installed at the outer surrounding of the tank 2 and circulates a thawing medium 51 for thawing the pure water 3 stored. A controller 6 controls the heating of the heating heater 4 and by circulating the thawing medium 51 in the jacket 5, ice is thawed from the inside and outside of the tank 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid tank and a liquid temperature management system, and more particularly to a pure water tank of a fuel cell power generation system used in vehicles, homes, etc., and a water temperature management system for managing the temperature of pure water stored in the pure water tank. About.

  A fuel cell power generation system supplies hydrogen as a fuel gas to one of electrodes arranged with an ion conductive membrane interposed therebetween, supplies oxygen as an oxidant gas to the other electrode, and reacts hydrogen with oxygen. To generate electric power. When supplying hydrogen and oxygen to the electrode, use pure water stored in a pure water tank to humidify hydrogen and oxygen in order to promote activation of power generation and prevent deterioration of the ion conductive membrane. There is a need.

  By the way, if the vehicle is stopped for a long time in a cold region or the like, the pure water in the pure water tank is frozen and the fuel cell power generation system cannot be started. In order to start this fuel cell power generation system, it is necessary to thaw frozen ice blocks of pure water.

As a conventional technique for solving such problems, the ice block in the pure water tank is thawed by circulating the heated refrigerant around the pure water tank at the start of the fuel cell power generation system, and attached to the pure water tank. There is known a fuel cell power generation system in which a heater is provided around a spare tank so that ice blocks in the spare tank are thawed by heating with the heater (see, for example, Patent Document 1).
JP 2000-149970 A (3rd and 4th pages, FIG. 1 and FIG. 2)

  However, in the fuel cell power generation system according to the prior art, the following points have not been considered. First, the heated refrigerant is circulated around the pure water tank, and the ice block in the pure water tank is thawed, and sufficient defrosting performance cannot be obtained with the heated refrigerant. Similarly, a heater is provided around the spare tank, and ice blocks in the pure water tank are thawed using pure water in the spare tank that has been thawed by heating with the heater, and pure water thawed in the spare tank. However, sufficient thawing performance cannot be obtained. For this reason, it takes a very long time to thaw the ice block in the pure water tank, and as a result, the start time of the vehicle becomes longer. Furthermore, as the vehicle start start time becomes longer, the power consumption increases and the hydrogen consumption also increases.

  Secondly, not only a sufficient thawing performance cannot be obtained, but the defrosted pure water in the pure water tank may be re-frozen depending on the outside air temperature.

  An object of the present invention is to provide a liquid tank and a liquid temperature management system that can shorten the thawing time of frozen pure water, prevent refreezing, and reduce excessive power consumption.

  In order to achieve the above object, the invention of claim 1 is provided in the tank, and a heater for thawing the stored liquid and a tank disposed on the outer periphery of the tank for thawing the stored liquid. And a jacket through which a thawing medium for distribution is distributed.

  According to a second aspect of the present invention, in the first aspect, the heater is composed of a first heater disposed in an upper part of the tank and a second heater disposed in a lower part of the tank. It is characterized by that.

  The invention of claim 3 is characterized in that, in claim 1, the cross-sectional shape of the heater is rectangular.

  The invention of claim 4 is characterized in that, in claim 1, the cross-sectional shape of the heater is circular or elliptical.

  According to a fifth aspect of the present invention, there is provided a liquid temperature management system for a liquid tank, which is disposed in the tank and is disposed in the outer periphery of the tank and stored in a heater for thawing the stored liquid. A liquid tank provided with a jacket for circulating a thawing medium for thawing the liquid, a temperature sensor for measuring the temperature of the heater, a water level sensor for detecting the position of the liquid surface stored in the tank, and a temperature sensor And a controller for controlling the heating of the heater based on the measurement result of the above and the measurement result of the water level sensor.

  According to the present invention, when the liquid stored in the tank becomes an ice block due to freezing, the ice block is directly thawed from the inside of the ice block by heating with the heater, and the ice block is externally removed by the thawing medium circulating in the jacket. Therefore, the ice block can be thawed in a shorter time than the method of thawing using the liquid heated in the reserve tank. Moreover, since an ice block can be thawed in a short time, extra power consumption can be reduced. Furthermore, the thawed liquid flowing inside the jacket can prevent the thawed liquid from refreezing.

  Hereinafter, an embodiment when the liquid tank and the liquid temperature management system according to the present invention are applied to a pure water tank and a water temperature management system of a fuel cell power generation system used in vehicles, homes, and the like will be described.

  As shown in FIG. 1, a pure water tank 1 according to Embodiment 1 of the present invention is provided in a tank (tank body) 2, a heater 4 for thawing the stored pure water 3, and a tank 2 and a jacket 5 for circulating a thawing medium 51 for thawing the pure water 3 stored in the tank 2.

  The tank 2 has a sealed structure so that the pure water 3 does not flow outside. The upper lid 9 has a return pipe 21 for supplying pure water from the outside to the inside of the tank 2 and pure water from the inside of the tank 2 to the outside. A suction pipe 22 for supplying water is disposed.

  In the first embodiment, the heater 4 includes a first heater 41 disposed in the upper part of the tank 2 and a second heater 42 disposed in the lower part of the tank 2. The 1st heater 41 is used when the water level which is the position of the surface of the pure water 3 stored is high. The first heater 41 is for thawing the upper part of the ice block when the pure water 3 freezes into an ice block. The first heater 41 has a slightly smaller planar size than the planar size in the tank 2, and the first heater 41 has a square cross-sectional shape. The temperature control of the first heater 41 is performed by the controller 6 disposed outside the tank 2.

  Similar to the first heater 41, the second heater 42 is used for thawing ice blocks frozen by the pure water 3, and the stored pure water 3 is either high or low. Also used. The second heater 42 has the same configuration as the first heater 41, and temperature control is performed by the controller 6. However, the first heater 41 and the second heater 42 may have different shapes.

  In the first embodiment, the jacket 5 is formed on the side surface and the bottom surface of the outer periphery of the tank 2 and has a hollow structure for circulating and circulating the thawing medium 51. The thawing medium 51 is supplied from the supply pipe 52 to the inside of the jacket 5 and discharged from the discharge pipe 53 to the outside of the jacket 5. The thawing medium 51 is circulated by a circulation system including a pump (not shown). As the thawing medium 51, for example, warm water can be used.

  In the pure water tank 1 configured as described above, when the pure water 3 stored in the tank 2 becomes an ice block due to freezing, the heater 6 is controlled by the controller 6 to control the heating from the inside of the ice block. Ice blocks can be thawed directly. At the same time, the ice block can be thawed from the outside by circulating the thaw medium 51 inside the jacket 5. As described above, since the ice blocks can be thawed by heating from the inside and outside of the tank 2, the ice blocks can be thawed in a shorter time than the method of using the pure water heated in the reserve tank to thaw. . According to this, for example, in a fuel cell power generation system used for a vehicle, the start start time of the vehicle can be shortened. In addition, since the ice block can be thawed in a short time, the extra power consumption can be reduced and the hydrogen consumption can also be reduced. In particular, in a fuel cell power generation system used in a vehicle, since a battery is used as a power source, battery consumption can be suppressed.

  Further, since the pure water tank 1 is provided with the jacket 5 around the outer periphery of the tank 2 and the thawing medium 51 is circulated inside the jacket 5, the pure water 3 thawed by the heater 4 is not re-frozen. Can be heated (insulated).

[Modification 1]
As shown in FIG. 2, the pure water tank 1 </ b> A according to the first modification of the first embodiment includes a heater 4 </ b> A configured by a first heater 43 and a second heater 44. Since the basic configuration of the pure water tank 1A is the same as that of the first embodiment, the description thereof is omitted. In the pure water tank 1A according to the first modification, the cross-sectional shapes of the first heater 43 and the second heater 44 are circular (or elliptical). Although not shown in a plan view, the first heater 43 and the second heater 44 are configured as so-called bar heaters.

  In the pure water tank 1A configured as described above, the cross-sectional shape of the heater 4A is circular (or elliptical), and the surface area of the heater 4A can be increased. The contact area between the ice block and the ice block is increased, and the ice block can be thawed. Therefore, the ice block can be thawed in a shorter time.

[Modification 2]
As shown in FIG. 3, the heater 4 </ b> B of the pure water tank 1 </ b> B according to the second modification of the first embodiment includes a first heater 45 and a second heater 46 that are formed in a strip shape. . In the pure water tank 1B according to the modification 2, the same effect as that obtained by the pure water tank 1A according to the modification 1 can be obtained.

  The second embodiment describes a water temperature management system that manages the water temperature of the pure water 3 stored in the pure water tank 1 according to the first embodiment.

  As shown in FIG. 4, the water temperature management system 10 according to the second embodiment includes a pure water tank 1 according to the first embodiment, a temperature sensor 7 that measures the temperature of the heater 4, and a pure water stored in the tank 2. A water level sensor 8 that measures the position of the surface of the water 3 and a controller 6 that controls the heating of the heater 4 based on the measurement result of the temperature sensor 7 and the measurement result of the water level sensor 8 are provided.

  A first temperature sensor 71 of the temperature sensor 7 is disposed in the first heater 41 of the heater 4, and the first temperature sensor 71 measures the temperature of the first heater 41 or a temperature in the vicinity thereof. A second temperature sensor 72 is disposed in the second heater 42, and the second temperature sensor 72 measures the temperature of the second heater 42 or the vicinity thereof.

  Next, the operation of the water temperature management system 10 will be described.

  First, the temperature of the first heater 41 of the heater 4 or the vicinity thereof is measured by the first temperature sensor 71 of the temperature sensor 7, and the measurement result is output to the controller 6. In the controller 6, it is determined whether or not the pure water 3 is frozen in the tank 2 of the pure water tank 1, particularly in the upper part. Similarly, the second temperature sensor 72 is used to measure the temperature of the second heater 42 or the vicinity thereof, and the measurement result is output to the controller 6. In the controller 6, it is determined whether or not the pure water 3 is frozen inside the tank of the pure water tank 1, particularly in the lower part. When it is determined that the pure water 3 is not frozen as a result of the measurement by the first temperature sensor 71 and the second temperature sensor 72, the controller 6 energizes the first heater 41 and the second heater 42. No control is performed without heating.

  When it is determined that the pure water 3 is frozen as a result of the measurement by the first temperature sensor 71 and the second temperature sensor 72, the controller 6 measures the water level of the pure water 3 in the tank 2 with the water level sensor 8. The instruction to do is output. The water level sensor 8 measures the water level of the pure water 3, and the measurement result is output to the controller 6. In the controller 6, the water level of the pure water 3 in the tank 2 is determined. As shown in FIG. 4, when the water level reaches a specified value exceeding the first heater 41, the controller 6 energizes the first heater 41 and the second heater 42 and controls to heat both. I do. Then, the temperature was continuously measured using the first temperature sensor 71 and the second temperature sensor 72, the ice block in the tank 2 thawed, and the pure water 3 reached a temperature suitable for humidification of hydrogen and oxygen. At the time, the controller 6 stops energizing the first heater 41 and the second heater 42, and stops any heating control.

  On the other hand, in the controller 6, as shown in FIG. 5, when the water level does not reach the prescribed value exceeding the first heater 41, the controller 6 energizes only the second heater 42, and this second heating Control to heat only the heater 42 is performed.

  In the water temperature management system 10 of the pure water tank 1 configured as described above, the first temperature sensor 71 disposed in or near the first heater 41 and the second heater 42 disposed in or near the first heater 41. The temperature of the pure water 3 is measured with the temperature sensor 72, and the first temperature sensor 71 and the second temperature sensor 72 are heated by the controller 6 based on the measurement result of the temperature and the measurement result of the water level of the water level sensor 8. Since the control is performed, the heater 4 is energized according to the water level of the pure water 3 in the tank 2, and the power consumption can be reduced.

  Furthermore, when the water level in the tank 2 has not reached the specified value, the energization of the first heater 41 can be stopped, so that empty cooking can be prevented.

  In the second embodiment, an example in which the temperature sensor 7 and the water level sensor 8 are individually disposed has been described. However, in the present invention, the temperature sensor 7 can also be used as the water level sensor 8.

  Further, the pure water tank 1 and the water temperature management system 10 according to the above embodiment are not limited to the pure water tank of the fuel cell system, but a tank that stores liquids such as general water (tap water, etc.), oil, chemicals and the like. In this case, the same effect can be obtained.

  Furthermore, the present invention may construct the water temperature management system 10 according to the second embodiment in the pure water tanks 1A and 1B including the heater 4 according to the first or second modification of the first embodiment.

1 is a schematic sectional view of a pure water tank according to Embodiment 1. FIG. FIG. 6 is a schematic cross-sectional view of a pure water tank according to Modification Example 1. FIG. 9 is a schematic cross-sectional view of a pure water tank according to Modification 2. FIG. 3 is a schematic cross-sectional view of a pure water tank and a water temperature management system according to a second embodiment. FIG. 5 is a schematic cross-sectional view of the pure water tank and the water temperature management system shown in FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Pure water tank 2 ... Tank 3 ... Pure water 4, 4A, 4B ... Heater 5 ... Jacket 6 ... Controller 7 ... Temperature sensor 8 ... Water level sensor 10 ... Water temperature management system 41, 43, 45 ... No. 1 heater 42, 44, 46 ... 2nd heater 51 ... thawing medium 71 ... 1st temperature sensor 72 ... 2nd temperature sensor

Claims (5)

A heater (4) disposed in the tank (2) for thawing the stored liquid (3);
A jacket (5) disposed around the tank (2) and circulating a thawing medium (51) for thawing the stored liquid (3);
A liquid tank characterized by comprising:   The heater (4) includes a first heater (41) disposed in the upper part of the tank (2) and a second heater (42) disposed in the lower part of the tank (2). The liquid tank according to claim 1, comprising:   The liquid tank according to claim 1, wherein a cross-sectional shape of the heater (4) is a square shape.   The liquid tank according to claim 1, wherein a cross-sectional shape of the heater (4A) is a circular shape or an elliptical shape. A heater (4) disposed in the tank (2) for thawing the stored liquid (3) and a liquid heater (4) disposed on the outer periphery of the tank (2) for thawing the stored liquid (3). A liquid tank (1) comprising a jacket (5) for circulating a thawing medium (51) for
A temperature sensor (7) for detecting the temperature of the heater (4);
A water level sensor (8) for detecting the position of the liquid surface stored in the tank (2);
A controller (6) for controlling heating of the heater (4) based on the measurement result of the temperature sensor (7) and the measurement result of the water level sensor (8);
A liquid temperature management system characterized by comprising:

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