JPH102616A - Evaporation block for heat storage heat pipe-type hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent heat stress from being applied to the evaporation part, and at the same time, prevent the heat transfer capability from decreasing for a structure wherein the evaporation part is integrally cast-in inserted in a heat storage body. SOLUTION: This hot water supply device is constituted in such a manner that at an evaporation part 2 of a loop-form heat pipe 1, a heat storage body 20 is provided, and at the same time, at a condensation part 3 of the heat pipe 1, a heat-exchanger 4 which obtains hot water by a heat-exchange with water, is provided. In this case, the evaporation part 2 is constituted of header pipes 11, 12 and a large number of steam generation tubes which communicate the header pipes 11, 12, and the hat storage body 20 is constituted by cast-in inserted the steam generating tubes with a metal of which the melting point is lower than that of the evaporation part 2 so that a gap (d) may be provided between the heat storage body 20 and the header pipes 11, 12. Then, a member 26 with a favorable thermal conductivity to cover the header pipes 11, 12 which are not cast-wrapped by the heat storage body 20, and comes into contact with the heat storage body 20, is provided so as to be freely fitted in the heat storage body 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus of the type in which heat stored in a heat storage body is taken out by a heat pipe when necessary to obtain hot water, and more particularly to a structure of an evaporating portion thereof.

[0002]

2. Description of the Related Art For example, as a small-scale household water heater, a type equipped with a hot water boiler, a type equipped with a hot water storage tank, a type equipped with a heat storage element, and the like are known. A model equipped with a hot water boiler has a disadvantage that the equipment cost (initial cost) is high for a small-capacity hot water supply device such as a private house because the equipment becomes large as a whole. A model with a hot water storage tank can reduce operating costs (running costs) by using relatively inexpensive late-night power, etc.
On the other hand, it is necessary to install a hot water storage tank having a large capacity, which is disadvantageous in that space is limited.

On the other hand, in a heat storage type heat pipe type hot water supply device having a heat storage body, the heat storage body can be used to reduce the size of the equipment. It can be stored stably. In addition, there are various advantages, such as high temperature being efficiently transported by the heat pipe, and heat exchange with water to obtain hot water safely. By the way, in this model, the heat storage element is an important constituent requirement, and the degree of freedom in selecting the installation location of the heat storage element is large.
It is desired that the thermal storage device be configured so as to have good thermal responsiveness and high long-term stability of heat storage characteristics. Therefore, a hot water supply device that can meet this demand has already been developed and proposed by the present applicant.

Conventionally, this type of heat storage type heat pipe type hot water supply apparatus is configured as shown in FIG. That is, a loop-type heat pipe 1 in which a condensable hydraulic fluid A such as Freon is sealed after vacuum degassing is provided.
A heat storage unit 20 is provided in the evaporating unit 2 and a heat exchanger 4 for exchanging water with warm water is provided in the condensing unit 3. The evaporating section 2 includes, for example, a stainless steel pipe group 10 and an upper header pipe 11 and a lower header pipe 1 which are arranged in parallel.
2, a number of evaporating tubes 13 are connected between the header tubes 11 and 12 in a grid pattern. The upper header pipe 11 is connected to the inlet of the serpentine pipe 6 of the heat exchanger 4 via the steam pipe 5, and the outlet of the serpentine pipe 6 is connected to the lower header pipe 12 via the return pipe 7 to form a closed loop. Make up.

[0005] The heat storage body 20 has a metal block 21 having excellent heat storage characteristics. In order to heat the pipe group 10 by storing heat in the metal block 21, an electric heater 22 is mounted inside the metal block 21. 21 is covered with a heat storage brick or the like. The pipe group 10 of the evaporator 2 is housed inside the metal block 21.

Here, the contact state between the metal block 21 and the pipe group 10 of the evaporating section 2 greatly affects heat transfer. Therefore, as the metal of the metal block 21, for example, cast iron or an aluminum alloy having a lower melting point than the pipe group 10 is used.
The entirety of the upper and lower header pipes 11 and 12 and the evaporating pipe 13 is integrally cast inside the interior of the housing 1 by casting. Then, the metal block 21 is applied to the entire surface of the pipe group 10.
The heat storage body 20 can be easily manufactured by ensuring close contact with the heat transfer member. In addition, the code | symbol 70 in a figure shows a valve.

With the above configuration, in the heat storage body 20, the metal block 21 is heated by the heat transfer heater 22,
High-temperature heat is stably stored in a small volume, and the heat of the metal block 21 is efficiently transmitted to the upper and lower header tubes 11 and 12 and the evaporator tube 13 of the evaporator 2. Therefore, in the evaporating section 2 of the heat pipe 1, the working fluid A evaporates with little thermal loss, and is well transported to the low-temperature heat exchanger 4,
This heat exchanges water W with warm water B to supply hot water.

In the above prior art, the metal block 21 is a single piece having a large capacity formed of a metal having a large thermal expansion such as an aluminum alloy.
Inside the evaporator 2, a group of metal pipes 10 of small thermal expansion such as stainless steel, that is, upper and lower header pipes 11, 1
The two evaporating tubes 13 are connected so as to communicate with each other and are integrally cast. For this reason, at the time of high-temperature heat storage of the metal block 21 or hot water supply of the heat pipe 1 by the hydraulic fluid A,
Although heat transfer efficiency is good, a thermal stress is applied to the pipe group 10 due to a difference in thermal expansion between the metal block 21 and the pipe group 10 of the evaporating section 2. Therefore, when used for a long time, the evaporator 2
Pipe group 10 may be deformed by thermal stress to cause various problems.

[0009]

Therefore, the upper and lower header tubes 11, 12 which are particularly liable to generate thermal stress are constructed so as not to be cast in the metal block 21, and the respective header tubes 11, 12 and the metal block 21 are not cast. If a configuration is provided in which a gap is provided between the metal block 21 and the metal block 21, the structure of the mold for forming the metal block 21 is simplified, and the above-described problem can be avoided at low cost.

However, as described above, each header tube 1
When the metal tubes 1 and 12 are exposed from the metal block 21, the heat transfer area between each of the header tubes 11 and 12 and the metal block 21 is naturally reduced, and the heat transfer performance is reduced.

In view of the foregoing, the present invention avoids thermal stress applied to a group of pipes in a metal block and integrally casts a group of pipes in an evaporating section inside a metal block. The purpose of the present invention is to prevent the heat transfer performance from being lowered.

[0012]

SUMMARY OF THE INVENTION In order to achieve this object, an evaporating block for a heat storage type heat pipe type hot water supply apparatus according to the present invention comprises a loop heat pipe in which substantially only a condensable hydraulic fluid is sealed. A heat storage element having a heat source is provided in the evaporating section of the heat pipe, and a heat exchanger for obtaining hot water by heat exchange with water is provided in the condensing section of the heat pipe. The above-mentioned header tube, the lower header tube, and a number of evaporating tubes communicating with each other, wherein the heat storage body is provided with a predetermined space between at least one of the evaporating tubes and the other header tube. Is formed by integrally casting with a metal having a melting point lower than that of the evaporating portion, and a portion having good thermal conductivity covering the other header tube not cast in the heat storage body and being in contact with the heat storage body. There is characterized in that is provided so as to loosely fit between the regenerator.

Therefore, in the present invention having the above configuration,
The evaporating tube group of the evaporating section is integrally cast and housed inside the heat storage body provided with the heat source, and the upper header tube or the lower header tube exposed to absorb thermal expansion also comes into contact with the heat storage body. Since it is configured to be covered with a member having good thermal conductivity, the heat transfer performance from the heat storage body to the evaporating section does not decrease, and the working fluid evaporates efficiently.

Further, since the member for covering the header tube is loosely fitted to the heat storage body, in other words, is not fixed to the heat storage body, even if a difference in thermal expansion between the heat storage body and the evaporating tube group occurs, it is unnecessary. Since no significant thermal stress is generated, deformation and damage of the pipe group can be reliably prevented even when used for a long time.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, the heat storage type heat pipe type hot water supply apparatus will be described in brief. The heat storage type heat pipe type hot water supply apparatus has a loop type heat pipe 1 in which a condensable hydraulic fluid A such as chlorofluorocarbon is filled in a reduced pressure state. 2, a heat storage body 20 is provided, and a heat exchanger 4 for exchanging heat of water W with warm water B is provided in the low-temperature condensing section 3.

2 and 3, the evaporator 2 and the heat storage 20 will be described in detail. The evaporating section 2 has an upper header pipe 11 and a lower header pipe 12 which are vertically arranged in parallel with each other.
3 are connected. And the upper header pipe 11 is connected to the inlet of the meandering pipe 6 of the heat exchanger 4 via the steam pipe 5,
The outlet of the meandering pipe 6 is connected to the lower header pipe 12 via the return pipe 7.
Connected to a closed loop.

These pipe groups 10 are, for example, stainless steel pipes, have low thermal expansion, and have high rigidity and corrosion resistance. Also, the working fluid A in the liquid phase condensed in the condenser section 3 flows into the lower header tube 12, whereas the working fluid A evaporated and vaporized gathers in the upper header tube 11. 11 is formed to have a larger diameter, and is configured so that the working fluid A is efficiently evaporated by the heat of the heat storage body 20 by the plurality of evaporating tubes 13. The heat storage body 20 has a metal block 21 having excellent heat storage characteristics.
Is formed in a narrow rectangular parallelepiped capable of covering the entire area of the plurality of evaporating tubes 13 of the evaporating section 2 as a whole. Here, when two sets of pipes 10 of the evaporator 2 are provided as shown in FIG. 3, for example, two metal blocks 21 are provided,
The evaporating tube 13 is accommodated inside each metal block 21.

In order to accumulate heat in the metal block 21 and to promote the evaporation of the working fluid A in the evaporating tube 13, electric heaters are provided inside and outside the evaporating tube 13 on the left and right in three places. 22 are mounted orthogonally. And 2
The individual metal blocks 21 are integrally fastened together with the heat storage bricks 23 disposed between and outside of the two, and are configured in a block shape, so that a large volume of heat can be stored in a small volume.

The metal block 21 constructed as described above
In order to reduce the thermal stress due to the difference in thermal expansion between the pipes 10 and the pipe group 10, the difference in thermal expansion may be individually absorbed in the axial direction between the upper and lower header tubes 11, 12 and the evaporating tube 13.

Therefore, the metal block 21 extends along the axial direction of each of the upper and lower header tubes 11 and 12, for example, one evaporator tube 1
Every three blocks 21a, 21b, 21c, 21
d. And each block 21a, 21
The pipe group 10 is integrally cast and housed inside b, 21c, 21d, and a gap c for absorbing individual thermal expansion is provided between the blocks.

Each of the blocks 21a, 21b, 21c,
In 21d, grooves 24 and 25 having a U-shaped cross section are formed in upper and lower portions. The upper and lower header tubes 11 and 12 are loosely fitted into these grooves 24 and 25, respectively. Accordingly, the metal block 21 substantially adheres only to the evaporating tube 13 for evaporating the working fluid A, and the metal block 21A of the evaporating tube 13 and the upper and lower header tubes 11 and 12 in the axial direction of the evaporating tube 13 are connected to each other. A gap d that absorbs the difference in thermal expansion between them is provided between them.

Here, since the header tubes 11 and 12 are exposed from the metal block 21, the heat transfer area is reduced. Therefore, as shown in FIGS. 3 and 4, a member 26 is provided which fits loosely into the grooves 24, 25 of the metal block 21 and the header tubes 11, 12 so as to cover the header tubes 11, 12. That is, the loose fitting member 26 is
And the header tubes 11 and 12, so that heat is transmitted between the metal block 21 and the header tubes 11 and 12 via the loose fitting member 26.

A specific method of manufacturing the metal block 21 will be described. First, a group of pipes 10 connected in a grid in advance is set in a mold, and the gaps c and d, the grooves 24,
A slit portion is formed at a position corresponding to 25 with a sand mold, a plate, or a cushioning material. If a metal such as an aluminum alloy is cast and cast, and then the slit portion is removed, it can be easily manufactured. When the above-described metal block 21 is cast, a hollow portion is formed in the metal block 21 using an appropriate core, and the electric heater 22 is inserted into the hollow portion to be built therein. The loose fitting member 26 is manufactured from a material having good thermal conductivity, such as aluminum, in a process different from that for the metal block 21.

Next, the operation of the heat storage type heat pipe hot water supply device configured as described above will be described. First, the metal block 21 is uniformly heated along the evaporator tube 13 by means of a child that energizes the electric heater 22 of the heat storage unit 20 using midnight power. Further, the heat of the metal block 21 is transmitted to the heat storage brick 23 and stored therein, and thus the heat storage body 20 can stably store a large amount of heat of several hundred degrees high even in a small volume.

Further, inside the metal block 21, the entire surface of the evaporating tube 13 in the pipe group 10 of the evaporating section 2 is in close contact with the metal block 21, and the upper and lower header tubes 11 and 12 are also in contact with the metal block 21. Heat is transmitted through the loose fitting member 26. Therefore, from the metal block 21 to the pipe group 10
Is transferred to the heat storage body 20 with high transfer efficiency,
The heat stored in the evaporator 2 is efficiently supplied to the evaporator 2.

Therefore, at the time of hot water supply, the working fluid A of the heat pipe 1
Flowing, the liquid hydraulic fluid A flowing into the lower header pipe 12 in the evaporating section 2 is mainly composed of a large number of vertical evaporating pipes 1.
At 3, the heat is evaporated by the heat of the heat storage body 20 with little thermal loss, and is collected in one upper header tube 11. Then, the vapor of the hydraulic fluid A in the upper header pipe 11 flows to the heat exchanger 4 of the condensing section 3 having a low temperature by the vapor pipe 5 and is satisfactorily transported, and the heat is generated by the meandering pipe 6 of the heat exchanger 4. Water W exchanges heat with hot water B and is supplied. In the heat exchanger 4, the working fluid A is condensed and liquefied, and the working fluid A in the liquid phase returns to the lower header pipe 12 again by the return pipe 7, and by repeating such a cycle, the heat of the heat storage body 20 is repeated. Hot water is supplied continuously.

At the time of heat storage of the above-mentioned heat storage body 20 or at the time of hot water supply with the working fluid A of the heat pipe 1, a metal block 21 made of aluminum alloy or the like and a stainless steel pipe group 1 inside thereof are used.
0 thermally expands differently depending on the capacity and the coefficient of thermal expansion of both, and the metal block 21 has a larger capacity and a larger coefficient of thermal expansion, so that a larger amount of thermal expansion occurs. However, the metal block 21 has a plurality of blocks 21a,
Each of the blocks 21a, 21b, 21c, and 21d is divided into a gap c.
And expands independently, and the expansion is absorbed. In the axial direction of the upper and lower header tubes 11 and 12 of the metal block 21, the overall thermal expansion is reduced by the upper and lower header tubes 11 and 12.
It will be as small as.

Each of the blocks 21a, 21b, 21c,
In 21d, the metal block 21 thermally expands also in the axial direction of the evaporating tube 13, but the metal block 21B of the upper and lower header tubes 11, 12 is thermally expanded irrespective of the header tubes 11, 12 by the grooves 24, 25. . At this time, the loose fitting member 2
6 is not fixed to the grooves 24 and 25,
3 does not prevent thermal expansion in the axial direction. Therefore, in the part of the evaporating tube 13, the metal block 21A is formed with the gap d.
As a result, thermal expansion is performed so as not to interfere with the upper and lower header tubes 11 and 12, and the difference is absorbed.

In this manner, any difference in thermal expansion in the vertical and horizontal axial directions between the metal block 21 and the upper and lower header tubes 11 and 12 and the evaporating tube 13 is absorbed. Therefore, deformation and damage of the pipe group 10 can be reliably prevented even if the pipe group 10 is used for a long time.

Although the embodiment of the present invention has been described above, the pipe group of the evaporating section may be spiral or meandering.

[0031]

As described above, according to the present invention, the evaporating tube group of the evaporating section is integrally cast and housed inside the heat storage body provided with the heat source, and is exposed to absorb the thermal expansion. The upper header pipe or the lower header pipe that has been made is also loosely fitted and covered with a member having good thermal conductivity in contact with the heat storage body, so that the heat transfer performance from the heat storage body to the evaporating section does not deteriorate, and the heat transfer performance is excellent. Even if the hydraulic fluid evaporates and there is a difference in thermal expansion between the heat accumulator and the evaporator tube group, no unnecessary thermal stress is generated, so that the pipe group is surely deformed and damaged even after long-term use. Is prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a specific example of a heat storage type heat pipe type hot water supply apparatus according to the present invention.

FIG. 2 is a sectional view of a main part of the specific example.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a sectional view of a main part of FIG. 3;

FIG. 5 is a configuration diagram showing a conventional heat storage type heat pipe hot water supply apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat pipe, 2 ... Evaporation part, 3 ... Condensing part, 4
... heat exchanger, 10 ... pipe group, 11 ... upper header tube, 12 ... lower header tube, 13 ... evaporation tube, 20 ... heat storage body, 21 ... metal block, 26 ... loose fitting member, d
... voids.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Koichi Mashiko 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd.

Claims (1)

[Claims] 1. A heat storage element having a heat source is provided in an evaporating section of a loop-shaped heat pipe in which substantially only a condensable working fluid is sealed, and a hot water is exchanged with water in a condensing section of the heat pipe. In the heat storage type heat pipe type hot water supply apparatus provided with a heat exchanger, the evaporator is composed of the header tube, the lower header tube, and a number of evaporator tubes communicating with each other, and the heat storage body is at least one. The evaporating tube and the other header tube are integrally cast with a metal having a melting point lower than that of the evaporating portion so as to provide a predetermined space between the evaporating portion and the other heat pipe. A heat storage type heat pipe type hot water supply device, wherein a member having good thermal conductivity, which covers the header tube and is brought into contact with the heat storage body, is provided so as to be loosely fitted between the heat storage body. Evaporating block