JP2007147263A - Hot water storage unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water storage unit capable of speedily supplying hot water in an appropriate temperature in a simple structure. <P>SOLUTION: The hot water storage unit includes a storage tank 3 with a water feed pipe 4 connected to its bottom part, a guide pipe 34 mounted in the storage tank 3 and extended almost to its upper part through which hot water flows, a hot water tapping pipe 5 connected to the upper part of the storage tank 3, a return pipe 6 for supplying hot water heat-exchanged with waste heat to the guide pipe 34, an intake pipe 33 provided at a bottom part of the storage tank 3 to take out cold water which is heat-exchanged with the waste heat and a supply pipe 7 for flowing out the cold water from the storage tank 3. The return pipe 6 and the supply pipe 7 are connected to the bottom part of the storage tank 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot water storage unit used in a cogeneration system or the like.

  A cogeneration system that generates electric power using an internal combustion engine (for example, a gas engine) and generates hot water using thermal energy (exhaust heat) generated along with the electric power generation has been put into practical use. In a cogeneration system, for example, by circulating a heat medium heated by a gas engine through a heat exchanger provided in a hot water storage tank, the water stored in the hot water storage tank is heated, and this hot water is converted into a predetermined device. Supplying to (a water heater, a bathtub, etc.) is performed (for example, refer patent document 1).

  A conventional hot water storage unit applied to a cogeneration system or the like is configured, for example, as shown in FIG. The hot water storage unit 1 shown in FIG. 4 includes a hot water storage tank 3 having a built-in heat exchanger 35 through which hot water generated by a generator 100 including a gas engine 101 and a heat exchanger 102 circulates. The hot water storage tank 3 includes a cylindrical container sealed with an upper flange 31 and a lower flange 32, and the container is supported by the base 2, and a water supply pipe 4 and a hot water discharge pipe are respectively provided on the lower flange 32 and the upper flange 31. 5 is connected. The lower flange 32 is connected to the other end of the heat exchanger 102 via the connecting pipe 9 and the return pipe 6 connected to one end of the heat exchanger 102 via the connecting pipe 8. An outgoing pipe 7 is connected. A circulation pump 11 and a temperature sensor 12 are installed in the middle of the forward pipe 7, and a safety valve 13 is installed in the middle of the return pipe 6. The heat exchanger 35 is formed of, for example, a coiled copper tube and is erected on the lower flange 32. 10a, 10b, 10c, and 10d are joints. According to this hot water storage unit 1, after the tap water is supplied from the water supply pipe 4 into the hot water storage tank 3, the circulating pump 11 is operated so that the heat medium heated by the exhaust heat of the gas engine 1 is stored in the hot water storage tank 3. While passing through the heat exchanger 35 provided inside the water, the water in the hot water storage tank 3 becomes hot water by heat exchange with the heat medium and is sent out from the hot water discharge pipe 5. Further, the heat medium cooled by the heat exchanger 35 and the tap water in the hot water storage tank 3 is fed to the heat exchanger 102 via the forward pipe 7. When it is confirmed by the temperature sensor 12 that the water temperature in the hot water storage tank 3 has reached a temperature in the vicinity of 80 ° C., for example, the circulation pump 11 is stopped. However, the hot water storage unit 1 is provided with a heat exchanger 35 in which a heat medium such as a brain flows inside the hot water storage tank 3, so that the heat medium is strongly prevented from being mixed into the water in the tank. A seal structure is required and the number of connecting portions increases, so that the number of seal portions also increases, resulting in a problem that the device is expensive. Also, in this system, the amount of heat of exhaust heat generated by the operation of the gas engine 101 is transferred to water through two heat exchangers, so heat loss in the heat exchanger also increases and exhaust heat recovery efficiency decreases. There is a problem of doing.

  In addition, in the field of electric water heaters, a hot water supply apparatus having a hot water storage tank having no heat exchanger has been proposed (see Patent Documents 2 and 3). The hot water supply apparatus described in Patent Document 2 is a horizontal hot water storage tank having a simple structure, and in order to prevent a short circuit from occurring between the return port and the water sampling port of the outgoing pipe during circulation heating, A return pipe to the hot water storage tank of the circulation piping system equipped with a circulation pump and a heater is made to penetrate the wall of the hot water storage tank, its tip is located in the vicinity of the upper wall surface of the hot water storage tank, and the return port at the tip Is configured to face the upper inner wall surface. The hot water supply apparatus described in Patent Document 3 mixes makeup water and heat source water, stores hot water in the hot water tank, and reduces the temperature difference of the hot water in the hot water tank from the top of the hot water tank. Is installed in the hot water tank, and a heat source water pipe in the hot water tank is covered with a substantially U-shaped mixing pipe, and a replenishment water pipe is externally provided in the hot water tank. Has a structure in which the leading end of the tube is joined to the mixing tube.

JP-A-8-4586 (page 3, FIG. 1) Japanese Utility Model Publication No. 5-32956 (page 5-7, FIG. 1) Japanese Patent No. 3470221 (page 2-3, FIGS. 1 and 2)

  The structure described in Patent Document 2 is effective for a horizontal tank (warm water that has flowed into a hot water storage tank when boiling is completed spreads across the entire horizontal direction of the tank, and low-temperature water is convected in the tank) In the case of a normal vertical tank, the hot water that has flowed into the hot water storage tank when boiling is completed may be discharged as it is. It is expected that the water will not be mixed with the water and the hot water of appropriate temperature cannot be obtained. The structure described in Patent Document 3 has a problem in that it is difficult to obtain high-temperature hot water because the makeup water pipe joins the heat source water pipe.

  Accordingly, an object of the present invention is to provide a hot water storage unit that can solve the above-described problems and can quickly discharge hot water at an appropriate temperature with a simple structure.

  In order to achieve the above object, a hot water storage unit of the present invention includes a hot water storage tank having a water supply pipe connected to the bottom, a guide pipe installed in the hot water storage tank, extending to the vicinity of the upper portion thereof, and flowing hot water. A hot water pipe connected to the upper part of the hot water storage tank, a return pipe for supplying hot water that has been heat-exchanged with exhaust heat to the guide pipe, and a heat exchanger that is provided at the bottom of the hot water storage tank and exchanges heat with the exhaust heat. A water intake pipe for taking out cold water and a forward pipe for allowing the cold water to flow out of the hot water storage tank are provided, and the return pipe and the forward pipe are connected to the bottom of the hot water storage tank.

  In the present invention, the guide pipe includes a straight pipe portion standing from the bottom of the hot water storage tank, and an inclined portion that is provided at an end of the straight pipe portion and supplies the hot water into the hot water storage tank. It is preferable that the axis of the inclined portion is inclined with respect to the straight pipe.

  In the present invention, the guide pipe includes a straight pipe portion standing from the bottom of the hot water storage tank and a tip portion provided at an end of the straight pipe portion for supplying the hot water into the hot water storage tank. The tip portion preferably has a supply hole for supplying hot water from a direction perpendicular to the axis of the straight pipe portion toward an upper range.

  In this invention, it is preferable that the said intake pipe is provided so that the edge part may face the said water supply pipe, and has a diameter smaller than the diameter of the said water supply pipe.

  In the present invention, an intermediate member is provided between the end of the water intake pipe and the end of the water supply pipe so as to extend the water supply pipe, and the inside of the intermediate member and the hot water storage are provided outside the intermediate member. It is preferable that a through hole communicating with the inside of the tank is provided.

  In the present invention, the guide tube preferably has a telescopic structure.

  In this invention, it is preferable that the said guide pipe is installed in the position where the axial center is eccentric from the axial center of the said water supply pipe | tube.

  According to the present invention, since the guide pipe extending near the upper portion is provided in the hot water storage tank, the hot water flowing into the hot water storage tank rises in the same direction as the tap water supplied to the hot water storage tank, and the hot water storage tank Is discharged at the top of the hot water tank, and mixing with tap water does not occur at the bottom of the hot water storage tank. Therefore, it is possible to obtain warm water having an appropriate temperature (for example, high temperature) in a shorter time than conventional. In particular, it is possible to adjust the temperature of hot water discharged by adjusting the height of the guide tube that can be expanded and contracted.

  In addition, according to the present invention, the hot water tank is provided with a guide pipe that extends to the vicinity of the upper portion thereof, and hot water is directly supplied to the vicinity of the upper portion of the hot water storage tank. Hot water can be obtained.

  Moreover, according to the present invention, since the structure does not include a heat exchanger, it is possible to realize a hot water storage tank that is low in cost and excellent in exhaust heat recovery efficiency.

(First embodiment)
Details of the present invention will be described below with reference to the drawings.
FIG. 1 is a piping diagram of a hot water supply apparatus including a hot water storage unit according to the first embodiment of the present invention, and the same functional parts as those in FIG. 4 are denoted by the same reference numerals. The hot water storage unit 1 includes a hot water storage tank 3 supported by a base 2, and in order to generate and store hot water, an internal combustion engine (for example, a gas engine) 101 that uses city gas or the like as fuel and heat from the exhaust heat. It is connected to an engine generator 100 having a heat exchanger 102 that performs the exchange. The hot water storage tank 3 for storing hot water is a sealed container having an upper flange 31 and a lower flange 32 attached to the top and bottom of an elongated cylindrical container, respectively, and a water intake pipe 33 erected on the lower flange 32 inside thereof. And a guide tube 34 are arranged. The guide pipe 34 is connected to the return pipe 6, and the return pipe 6 is connected to one end of the heat exchanger 102 via the connecting pipe 8. The intake pipe 33 is connected to the forward pipe 7, and the forward pipe 7 is connected to the other end of the heat exchanger 102 via the connecting pipe 9. Thereby, the piping in which the water in the hot water storage tank 3 circulates via a heat exchanger is comprised. A hot water discharge pipe 5 is connected to the upper part of the hot water storage tank 3. Reference numerals 10a, 10b, 10c, and 10d are joints.

  Details of each part of the hot water storage unit 1 are as follows. Although not shown in the figure, the hot water storage tank 3 is made of, for example, a resin (for example, polyethylene) or stainless steel inner container and a heat insulating material (for example, foamed urethane foam) and a steel plate or resin for covering the inner container made of stainless steel. A three-layer structure of the outer container is preferable. A normal hot water storage tank has a capacity of about 100 to 450 l and is applied to various facilities such as hotels and hospitals in addition to general households. The diameters of the water supply pipe 4 and the hot water discharge pipe 5 are set in accordance with the use conditions. In general households, there is no special problem if a water supply pipe having a nominal diameter of 25 A or less is connected to a hot water storage tank. In various facilities such as hotels and hospitals, a large amount of hot water (for example, about 300 l / min) is consumed, so that a sufficient amount of water is supplied to the hot water storage tank and a large amount of hot water is discharged therefrom. It is preferable to connect a water supply pipe and a hot water discharge pipe having a large diameter (for example, a nominal diameter of 50A to 150A) to a hot water storage tank. When the water supply pipe 4 and the hot water pipe 5 having such a diameter are used, the nominal diameter of the return pipe 6 and the forward pipe 7 is preferably in a range of 20A to 25A. Further, it is preferable that the diameter of the intake pipe 33 is set smaller than the diameter of the water supply pipe 4 and that the intake port of the intake pipe 33 is opposed to the tank side end of the water supply pipe 4. By doing so, the lowest temperature water is reliably taken almost directly into the water intake pipe 33 from the water supply pipe 4 and fed to the heat exchanger 102 without involving hot water inside the hot water storage tank, particularly around the water intake pipe 33. Can do.

  The guide pipe 34 is an elongated pipe extending from the bottom to the top of the hot water storage tank 2, and has a large diameter pipe 34 a fixed to the lower flange 32 and a small diameter pipe 34 b slidably supported by the pipe 34. In addition, the tip of the small-diameter pipe 34b is bent obliquely with respect to the straight pipe part to form an inclined part 341. The height h1 of the guide pipe 34 can be adjusted by pulling out the small diameter pipe 34b from the large diameter pipe 34a by a predetermined length and fixing the small diameter pipe 34b to the large diameter pipe 34a by means not shown in the figure, so that the tapping temperature can be changed. is there. That is, when h1 is increased, the portion that is mixed with the water stored in the hot water storage tank 2 is small, and the high temperature region 30a formed at the top of the hot water storage tank 2 is narrowed. The part mixed with the stored water is increased, the high temperature region 30a is expanded, and the temperature of the hot water discharged is lowered. Therefore, h1 may be set high when trying to obtain high-temperature hot water, and h1 may be set low when trying to obtain low-temperature hot water. For example, when trying to obtain hot water of 80 ° C., if the height of the hot water storage tank 2 (inner dimensions) is h0, the dimensions are set such that h1 / h0 falls within the range of 0.6 to 0.7. It is preferable. The height h2 of the inclined portion 341 is set in a range of 0.02 to 0.05 times the height h1 of the guide tube 34 and is inclined by about 20 to 25 ° with respect to the straight tube portion, whereby hot water is stored in the hot water storage tank. It becomes possible to discharge evenly to the upper part of 2. The guide tube 34 may have a structure other than the above as long as the height h1 can be adjusted.

  Further, it is desirable that the amount of hot water stored in the high temperature region 30a and the water supplied from the water supply pipe 4 is small, and the guide pipe 34 has a flow of water supplied from the water supply pipe 4 as shown in FIG. In order to reduce the influence of the above, it is desirable to stand upright from the axis of the water supply pipe 4.

  The intake pipe 33 is an inverted U-shaped piping member for efficiently taking out low-temperature water staying at the bottom of the hot water storage tank 3, and its height h3 is 0.05 to 0.3 in h3 / h0. And the height h4 of the U-shaped part is preferably set to a dimension that is about half of h3. When the water supply pipe 4 and the hot water discharge pipe 5 having the above-described diameter are used, the nominal diameter of the guide pipe 34 and the water intake pipe 33 is preferably in a range of 20A to 25A.

An example of the hot water supply operation by the hot water supply apparatus will be described with reference to FIG. First, by supplying tap water from the water supply pipe 4 to the hot water storage tank 3, the tap water rises as indicated by the arrow F1 due to the water pressure, and the hot water storage tank 3 is filled with the tap water. Next, the circulation pump 11 is operated to circulate a part of the water in the hot water storage tank 3. In this circulation process, the water in the hot water storage tank 3 is fed from the intake pipe 33 to the heat exchanger 102 via the forward pipe 7 and the connecting pipe 9, and then heated by the exhaust heat of the gas engine 101 in the heat exchanger 102. The hot water is exchanged with the heat medium to generate hot hot water, and the hot water passes through the connecting pipe 8 and the return pipe 6 and is fed to the hot water storage tank 3. Hot hot water that has flowed into the hot water storage tank 3 moves up the guide tube 34 as shown by the arrow F2 in the drawing, and is discharged from the inclined portion 341 at the tip toward the top of the hot water storage tank 2. This hot water is mixed with water present in the high temperature region 30a in the hot water storage tank 3 to obtain hot water having an appropriate temperature. The obtained hot water is discharged from the hot water discharge pipe 5 to the outside of the hot water storage tank 3 by water pressure, and is used for drinking or bathing, for example, from a terminal faucet (not shown). Since the specific gravity when the temperature of water becomes higher becomes lighter (specific gravity of water, for example 20 ° C. In 998.2Kg ^/ m 3, 40 ℃ in 992.2Kg ^/ m 3, 60 ℃ in 983.2Kg / ^{m 3} , At a temperature of 80 ° C., 971.8 Kg / m ³ ), by repeating the circulation process, low temperature water stays in the low temperature region 30 b, and the water is taken out from the water intake pipe 33 and connected to the outgoing pipe 7 and the connecting pipe 9. Then, it is fed to the heat exchanger 102. On the other hand, since hot hot water is continuously supplied to the high temperature region 30a in the hot water storage tank 3, hot water at an appropriate temperature can be continuously discharged from the hot water discharge pipe 5. In addition, by providing a safety valve (not shown) in the hot water discharge pipe, when the pressure and temperature inside the hot water storage tank 3 exceed a set value (for example, pressure: 0.49 MPa, temperature: 80 ° C.), the pressure is externally supplied from the safety valve. The hot water supply operation can be performed safely.

(Second Embodiment)
FIG. 2 is a perspective view showing a lower flange portion of the hot water storage unit according to the second embodiment of the present invention. Further, the same functional parts are denoted by the same reference numerals as in FIG. 1, and the other parts are the same as the hot water storage unit shown in FIG.
A water supply pipe 4, a return pipe 6, an outgoing pipe 7, a water intake pipe 33, and a guide pipe 34 are fixed to the lower flange 32 as in the hot water storage unit of FIG. 1. A cylindrical intermediate member 35 provided between the end of the intake pipe 33 and the end of the water supply pipe 4 on the hot water storage tank side is provided inside the hot water storage tank 3 so as to extend the water supply pipe 4 and closed at the upper end. Is provided. An opening 36 into which the end of the intake pipe 33 can be inserted is provided at the upper end of the intermediate member 35, and the end of the intake pipe 33 is inserted into the opening 36. A plurality of through holes 37 are formed outside the intermediate member 35 so that the inside of the intermediate member 35 communicates with the inside of the hot water storage tank 3.

According to this hot water storage unit 1 </ b> A, the tap water supplied from the water supply pipe 4 to the hot water storage tank 3 first flows to the intermediate member 35. Since the upper end portion of the intermediate member 35 is closed, the inflowing tap water is supplied into the hot water storage tank 3 from a through hole 37 provided outside the intermediate member 35. In this way, by suppressing the flow along the tube axis direction of the supply pipe 4 that occurs in the hot water storage tank 3 during the supply of tap water, agitation in the hot water storage tank 3 due to water supply is reduced.
Further, since the water intake pipe 33 takes out the tap water through the intermediate member 35, it is possible to take out water having a low temperature inside the intermediate member 35. As a result, low temperature water can be reliably taken almost directly from the water supply pipe 4 into the water intake pipe 33 and fed to the heat exchanger 102 without involving hot water around the water intake pipe 33.

(Third embodiment)
FIG. 3 is a perspective view showing a lower flange portion of the hot water storage unit according to the third embodiment of the present invention, and in particular, an enlarged view of the distal end portion of the guide tube. The same functional parts are denoted by the same reference numerals as those in FIG. 1, and the other parts are the same as the hot water storage unit shown in FIG.
The distal end portion 34c is a cylindrical member provided at the distal end of the straight tube portion 34a of the guide tube 34, the upper end portion of which is closed, and on its side surface, a plurality of supplies in which the inner peripheral portion and the interior of the hot water storage tank 33 communicate with each other. A hole 38 is provided. A guide plate 39 that extends horizontally outward in the radial direction is provided below the supply hole 38.

According to this hot water storage unit, hot hot water heated by the heat exchanger 102 reaches the distal end portion 34 c via the connecting pipe 8 and the guide pipe 34, and is supplied into the hot water storage tank 3 from the supply hole 38. Since the supply hole 38 is provided on the side surface of the tip portion and has a guide plate 39 below the supply hole 38, the hot water extends along the guide plate 39 from the direction perpendicular to the axis of the straight pipe portion 34 a to the upper range. Will be preferentially supplied. As a result, mixing of water in the low temperature region 30 b below the hot water storage tank 3 and high temperature hot water is suppressed, and the high temperature region 30 a can be stably formed in the upper part of the hot water storage tank 3.
The hot water supply unit of the present invention is not limited to the structure described above, and various modifications can be made within the scope of achieving the object. For example, when there is little fluctuation in the amount of hot water and it is not necessary to adjust the height of the guide tube, a guide tube having a predetermined height may be prepared and fixed to the lower flange 32.

It is a piping diagram of the hot water supply apparatus provided with the hot water storage unit concerning the 1st Embodiment of this invention. It is a perspective view which shows the part of the lower flange of the hot water storage unit concerning the 2nd Embodiment of this invention. It is a perspective view which shows the part of the lower flange of the hot water storage unit concerning the 3rd Embodiment of this invention. It is a piping diagram of the hot water supply apparatus provided with the conventional hot water storage unit.

Explanation of symbols

1, 1A, 1B: Hot water storage unit 2: Base 3: Hot water storage tank, 30a: High temperature area, 30b: Low temperature area, 31: Upper flange, 32: Lower flange, 33: Intake pipe, 34: Guide pipe, 34a: Large Diameter pipe, 34b: Small diameter pipe, 34c: Tip part, 341: Inclined part, 35: Intermediate member, 36: Opening, 37: Through hole, 38: Supply hole, 39: Guide plate 4: Water supply pipe, 5: Hot water pipe , 6: return pipe, 7: forward pipe, 8, 9: connecting pipe, 10a, 10b, 10c, 10d: joint, 11: circulation pump, 12: temperature sensor 100: generator, 101: gas engine, 102: heat Exchanger

Claims (7)

A hot water storage tank with a water supply pipe connected to the bottom;
A guide pipe installed in the hot water storage tank, extending to the vicinity of the upper part thereof, and flowing hot water;
A hot water pipe connected to the upper part of the hot water storage tank;
A return pipe for supplying the guide pipe with hot water heat-exchanged with exhaust heat;
A water intake pipe that is provided at the bottom of the hot water storage tank and takes out cold water that exchanges heat with the exhaust heat;
An outward pipe for letting out the cold water from the hot water storage tank;
The hot water storage unit, wherein the return pipe and the forward pipe are connected to the bottom of the hot water storage tank.
The guide pipe is a straight pipe portion erected from the bottom of the hot water storage tank;
It is provided at the end of the straight pipe part, and comprises an inclined part that supplies the warm water into the hot water storage tank,
The hot water storage unit according to claim 1, wherein an axis of the inclined portion is inclined with respect to an axis of the straight pipe.
The guide pipe is a straight pipe portion erected from the bottom of the hot water storage tank;
It is provided at the end of the straight pipe part, and comprises a tip part for supplying the hot water into the hot water storage tank,
The hot water storage unit according to claim 1, wherein the tip has a supply hole for supplying hot water from a direction perpendicular to the axis of the straight pipe portion toward an upper range.
The intake pipe is provided with an intake port formed at an end thereof facing the end of the water supply pipe,
The hot water storage unit according to any one of claims 1 to 3, wherein the hot water storage unit has a diameter smaller than a diameter of the water supply pipe.
An intermediate member is provided between the end of the intake pipe and the end of the water supply pipe so as to extend the water supply pipe,
The hot water storage unit according to any one of claims 1 to 4, wherein a through hole is provided outside the intermediate member so that the inside communicates with the inside of the hot water storage tank.
The hot water storage unit according to any one of claims 1 to 5, wherein the guide tube has an extendable structure.
The hot water storage unit according to any one of claims 1 to 6, wherein the guide pipe is installed at a position where an axis of the guide pipe is eccentric from an axis of the water supply pipe.

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