JPH0387561A - Heat pipe type hot-water supply apparatus with high temperature heat accumulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a water heater that obtains hot water by imparting heat from a heat storage body to water via a heat pipe, and in particular to a heat pipe type water heater that uses a heat storage body with a high heat storage temperature. The present invention relates to a water heater.

Conventional technology Water heaters used in small-scale facilities such as ordinary homes must not only quickly provide hot water at a sufficient temperature and quantity, but also be compact and have low running costs. It will be done. Therefore, with water heaters that heat water using electric heaters or gas burners, it takes a long time from when a faucet cock is opened (such as when hot water is requested) to when the hot water is actually supplied, resulting in a lack of quick hot water supply. Moreover, when an electric heater is used as a heat source, there is the inconvenience that cheap late-night electricity cannot be used.On the other hand, in devices equipped with a hot water storage tank, a faucet cock is used to constantly store hot water at a predetermined temperature. Although it is possible to obtain hot water at the same time when the opening ε is opened, and it is also possible to use cheap late-night electricity, there is the problem that the equipment becomes larger because it requires a large-capacity hot water storage tank. Applicants connect a heat storage body and a heat exchanger with a heat pipe, and the heat stored in the heat storage body is conveyed to the heat exchanger via the heat pipe according to the demand for hot water supply, and the water is heated here to produce hot water. We have already proposed a device configured to obtain

Problems to be Solved by the Invention By the way, in the device proposed by the applicant, etc., the heat pipe that conveys the heat of the heat storage body to the heat exchanger has a temperature of about 80°C at most, so the temperature of the hot water is about 80°C. Alternatively, a similar condensable fluid may be used as the working fluid.

Furthermore, in order to reduce the size of the device, it is desirable that the heat storage body has as much heat storage capacity as possible per unit volume, and accordingly, the heat storage temperature will also be high. Therefore, in the heat receiving part of the heat pipe, that is, the part that contacts the heat storage body so that heat can be transferred and received, heat is applied to the working fluid from the outside at a temperature considerably higher than the boiling point of the working fluid. If the inner surface temperature of the heat pipe is such a high temperature, the Leiden strike phenomenon may occur and the evaporation of the working fluid may become slow. In other words, when the inner surface temperature of the heat pipe becomes about 10°C higher than the temperature of the working fluid, evaporation occurs instantaneously on the surface of the first working fluid droplet that comes into contact with the inner surface of the heat pipe, and the vapor heats the droplet. Heat transfer to the droplets is inhibited by separating them from the inner surface of the pipe, and as a result, it takes a considerable amount of time for the entire volume of the droplets to completely turn into steam, a phenomenon known as the Leidenfrost phenomenon. When such a phenomenon occurs, the heat transport ability of the heat pipe decreases, causing the inconvenience that hot water cannot be obtained at a sufficient speed.

In order to eliminate this inconvenience, it is possible to use heat pipes that use mercury or potassium as the working fluid, which has a high boiling point, but such heat pipes are expensive and require considerable care when handling. This makes it unsuitable for water heaters used in small-scale facilities such as general households.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small and inexpensive water heater that can rapidly supply hot water even when the heat storage temperature is increased.

Means for Solving the Problems In order to achieve the above object, the present invention provides an evaporation section of a heat pipe in which a condensable fluid is sealed as a working fluid in a closed container from which a non-condensable gas has been degassed. , a heat pipe type water heater in which the high temperature heat storage body is brought into contact with the high temperature heat storage body so as to be able to transfer heat thereto, and the condensing part of the heat pipe is a heat exchange part that exchanges heat with water; The evaporator is characterized in that a protrusion extending inward is provided on the inner surface of the evaporator which is brought into contact with the evaporator so as to be able to transfer heat to and receive heat from the evaporator.

Function: In the device of the present invention, the evaporating section of the heat pipe comes into contact with a heat storage body having a considerably higher temperature than that of the working fluid, and the condensing section of the heat pipe serves as a heat exchange section for exchanging heat with water. Therefore, the working fluid evaporates at the end on the heat storage body side, and after the vapor flows to the heat exchanger side, it radiates heat and condenses. That is, the heat possessed by the heat storage body is carried to the heat exchange section via the heat pipe, and the water is heated to become hot water.

In that case, as the temperature of the heat storage body is higher than the temperature of the working fluid, the temperature of the inner surface of the heat pipe becomes higher than the temperature of the working fluid, and therefore the droplets of the working fluid that come into contact with the inner surface of the heat pipe do not evaporate immediately. However, since there are protrusions on the inner surface of the heat pipe, the working fluid in the form of droplets comes into contact with the protrusions and is ejected from the inner surface of the heat pipe. At the same time as it removes heat, it is divided by the protrusions, and as a result, evaporation is accelerated. In particular, since the heat capacity of the protrusions is small, the inner surface of the heat pipe does not reach any high temperature at all times, so the Leidenfrost phenomenon is less likely to occur here, and the evaporation of the working fluid in the form of droplets is also promoted in this respect.

Example Next, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and is an example in which a loop-type heat pipe 1 is used. In other words, the evaporator 2 has an upper header pipe 3 and a lower header pipe 4.
A plurality of vibrators 5 are arranged in parallel with each other between the two to form a grid-like structure as a whole, and the condensing part 6 is also arranged in parallel with each other.
A plurality of pipes 9 are arranged parallel to each other between the upper header pipe 7 and the lower header pipe 8 to form a lattice shape as a whole. The evaporating section 2 is disposed at a lower position than the condensing section 6, and the upper header pipes 3 and 7 are connected to the steam pipe 1.
0, and the lower header pipes 4.8 are communicated with each other by a liquid return pipe 11, and the liquid return pipe 11
A liquid reservoir section 12 and a flow rate regulating valve 13 are interposed below the reservoir section 12, respectively. Inside the pipe line, which is formed in a loop shape as a whole, there is water, etc. whose boiling point is 1.
A condensable fluid of about 00° C. is sealed as a working fluid 14 .

The entire evaporator 2 described above is in contact with the high-temperature heat storage body 16 so as to be able to transfer heat thereto by being buried inside the high-temperature heat storage body 16 covered with a heat insulating material 15 . Here, the high-temperature heat storage body 16 stores heat at a temperature higher than the boiling point of the working fluid 14, and is specifically made of cast iron, steel, ceramic, rock, etc. Store heat.

Further, a needle-like protrusion 17 facing inward is provided inside the pipe 5 in the evaporation section 2 described above.

For example, as shown in FIGS. 2 and 3, a wire mesh 18 that acts as a wick is placed along the inner surface of the pipe 5, and the wire is partially cut, and the cut portion is placed inside. It can be formed by bending and protruding, or the wire mesh may be partially cut and the cut portion may be bent inward. Further, as such a wire mesh 18, a wire having a diameter of l+a+ and a mesh coarseness of about 10 meshes can be used.

On the other hand, the condensing section 6 is surrounded in a watertight manner by a jacket 21 having a water supply port 19 and a tap water outlet 20, and a heat exchange section for exchanging heat with water is formed here.

In the water heater having the above-described configuration, heat is stored by heating the heat storage body 16 to, for example, about 500° C., and the flow rate regulating valve 13 is opened while water is being supplied to the inside of the jacket 21 so that the liquid phase is increased. When the working fluid 14 of
Each header pipe 3, 4 and pipe 5 due to the capillary pressure at 8
sent inside. The working fluid t4 is the evaporator 2
is heated by the heat storage body 16, the header pipes 3 and 4 and the pipe 5 that make up the container of the heat pipe 1
It is heated by the heat storage body 16 through the tube wall of the tube. In that case, since the temperature of the heat storage body 16 is significantly higher than the boiling point of the working fluid 14, the liquid-phase working fluid 14 that comes into contact with the inner wall surface of the heat pipe 1 does not evaporate immediately, but becomes liquid due to the Leidenfrost phenomenon. A situation occurs in which the droplets are splashed inward from the inner wall surface of the heat pipe 1. As schematically shown in FIG.
By crossing it, you will be stuck in it, but
Since the needle-like protrusion 17 is also heated by heat transfer from the inner wall surface of the heat pipe 1, the droplet stuck to it is heated from within, and as a result, the liquid droplet of the working fluid 14 Evaporation of the droplets is accelerated. The heat is removed from the needle-like protrusion 17 by the evaporation of droplets of the working fluid 14 in contact with the needle-like protrusion 17. However, since the needle-like protrusion 17 has a small volume and a small heat capacity, the working fluid 14
The temperature of the needle-like protrusion 17 is maintained at a lower temperature than other parts such as the inner wall surface of the heat pipe 1 due to the continuous contact and evaporation of the droplets.
7, the Leidenfrost phenomenon is prevented from occurring, and the evaporation of the working fluid 14 at the needle-like protrusion 17 becomes active.

Furthermore, the droplets of the working fluid 14 that cross the needle-like protrusion 17 are divided by the needle-like protrusion 17 and become small droplets.
Evaporation of the working fluid 14 is also promoted in this respect.

The working fluid 14 vaporized as described above is transferred to the steam pipe 10
The water flows through the condensing section 7, where the water in the jacket 21 absorbs heat and condenses, and at the same time the water is heated and becomes hot water. The liquefied working fluid 14 then returns to the liquid reservoir 12 through the liquid return pipe 11.

Here, we will show test examples and comparative examples conducted by the inventors to confirm the effects.

(Test example) Inside the part of the sealed tube that constitutes the heat pipe that will become the evaporation section, an IO mesh wire mesh with a wire diameter of approximately 1 m is placed along the inner surface, and the wire is placed at multiple locations. It was cut and protruded inward to form a needle-like protrusion. In addition, water was sealed as a working fluid to create a heat pipe. The evaporation section was heated to about 500° C. while the other end of the heat pipe, which became the condensation section, was water-cooled. When we investigated the temperature transition of the working fluid vapor in the heat pipe immediately after the heating started, we found that it was approximately 1
The temperature reached 100°C in 0 seconds, 120°C in about 15 seconds, and became stable thereafter.

(Comparative Example) Perform the same operation as the above test using a general heat pipe without the wire mesh and needle-shaped protrusions in the above test example. When I investigated the temperature transition of the working fluid vapor inside the heat pipe, I found that it was 50℃ in about 10 seconds, 55℃ in about 15 seconds,
The temperature reached 100°C in about 300 seconds.

From these test examples and comparative examples, it was found that by providing needle-like protrusions or similar protrusions inside the evaporation section of the heat pipe, it was possible to improve the so-called rise at the start of heat transport of the heat pipe.

Therefore, in the water heater having the above-described configuration, heat is quickly and abundantly transferred from the evaporating section 2 in contact with the heat storage body 16 to the condensing section 6 in contact with the heat exchanger. We can supply it quickly if required.

In addition, although the above-mentioned embodiment has been explained using an example using a loop-type heat pipe, the heat pipe in the present invention is not limited to a loop-type heat pipe.

Effects of the Invention As is clear from the above explanation, in the water heater of the present invention, even if the temperature of the heat storage body is higher than that of the working fluid, the working fluid can be quickly evaporated. You can get a water heater. In other words, since the heat storage temperature can be increased without impairing responsiveness, the heat storage body can be downsized, and the entire device can be downsized.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention;
Figure 2 is a partial cross-sectional view of the evaporation section, and Figure 3 is m in Figure 2.
FIG. 4, a cross-sectional view taken along line -m, is a schematic diagram for explaining a state in which a droplet of working fluid is in contact with a needle-like protrusion. 1... Heat pipe, 2... Evaporation section, 6...
Condensing section, 10... Steam pipe, 11... Liquid return pipe,
14... Working fluid, 16... High temperature heat storage body, 17
...Acicular process, 21...Jacket.

Claims (1)

[Scope of Claims] An evaporation section of a heat pipe, which is formed by sealing a condensable fluid as a working fluid in a closed container from which a non-condensable gas has been degassed, is brought into contact with a high-temperature heat storage body so as to transfer heat thereto, and In a heat pipe water heater in which a condensing section of a pipe is used as a heat exchange section for exchanging heat with water, an inner surface of an evaporating section of the heat pipe that is brought into contact with the high temperature heat storage body so as to be able to transfer heat to and from the water is provided. A heat pipe water heater equipped with a high-temperature heat storage body characterized by having a protrusion extending toward.