JPH02187594A - Heat pipe type heat exchanger - Google Patents

Abstract

PURPOSE:To make a stabilized supply of heat possible even when changes occur in heat energy from a heat source by placing the vaporizing part of a first heat pipe in high temperature heat medium and the oppositely functioning part of a second heat pipe in cold temperature heat medium. CONSTITUTION:When the heat energy from waste gas H as a heat source is abundantly available, the effective length L of the condensing part of a first heat pipe 14 enlarges with increase of the vapor pressure and reduction of the volume of noncondensable gas 15; then low temperature heat medium is heated and surplus heat is stored in a heat storage tank 13. When the heat energy from the heat source decreases, automatic control works with fall of the vapor pressure in the first heat pipe 14 in such a manner as to cause the volume of the noncondensable gas 15 to expand and the effective length of the condensing part to decrease so that the heat received is used only for heating the low temperature heat medium. When the heat energy from the high temperature heat medium is insufficient, the part C of a second heat pipe 17, placed in the heat storage tank 13, functions as a vaporizing part in a bottom heat mode; then heat stored in the heat-storing material is transferred to the part placed in the low temperature heat medium so as to supply the insufficiency of heat energy. As a result, stabilized heating of the low temperature heat medium can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a heat exchanger using a heat pipe, suitable for a steam generator or the like of a combined heat/electricity supply system (co-generation system).

Conventional technology Tubular or shell-and-tube heat exchangers are often used in steam generators for conventional combined heat and electricity supply systems, which generate steam by directly applying heat to water from a heat source such as waste gas. A method is used to generate

Figure 4 shows an example of a conventional combined heat/electricity supply system using a tubular heat exchanger.
The gas engine 2 drives the generator 1 with a gas engine 2 to generate and supply electricity and also drives the generator 1.
A tubular heat exchanger 4 as a steam generator is interposed in the exhaust gas passage 3 of is supplied to an absorption cooler (not shown) or the like. In addition, water is circulated through the heated portion of the gas engine 2 for cooling, and the heated cooling water is sent to a heat supply facility or the like for use.

Problems to be Solved by the Invention However, in the heat/electricity combined supply system that uses the conventional tubular heat exchanger 4 as a steam generator, the load on the gas engine 2 that supplies waste gas, which is the heat source, decreases. In this case, the thermal energy of the waste gas also decreases, resulting in a problem that the required amount of steam cannot be secured. Therefore, in conventional devices of this type, when hot steam (hot steam) is required, the load on the gas engine 2 is increased even when electricity is not required, increasing the thermal energy of the waste gas that is the heat source. There was a lot of wasted energy because it had to be done.

This invention was made against the above-mentioned technical background.
It is an object of the present invention to provide a heat pipe type heat exchanger that can achieve stable heat supply even if there are fluctuations in the thermal energy of a heat source.

Means for Solving the Problems As a means for solving the above-mentioned problems, the heat pipe type heat exchanger of the present invention has a non-condensable heat exchanger installed at the end side of the condensing part in a container pipe in which a condensable working fluid is sealed. a variable conductance type first heat pipe which encloses a reactive gas so that it can be compressed and expanded according to fluctuations in the vapor pressure of a working fluid;
A heat storage material provided on the outer periphery of the end of the condensing part of the toe pipe, and a second heat pipe of a gravity-operated heat flow diode heat pipe with one end disposed in the heat storage material and the other end raised. The evaporating part of the first heat vibrator is disposed in a high-temperature heat medium, and the part of the condensing part other than the part where the heat storage material is provided on the outer periphery is disposed in the low-temperature heat medium, and The other end side of the second heat pipe is disposed in the low-temperature heat medium.

Function As mentioned above, the first heat vibrator of the variable conductance type in which the heat storage material is provided on the end side of the condensing part has a heat storage material on the end side of the condensing part in which non-condensable gas is sealed. The non-condensable gas prevents it from functioning as a condensing section, and only the portion of the condensing section that is free of non-condensing gas effectively functions as a condensing section. In addition, the enclosed non-condensable gas compresses or expands in response to changes in the vapor pressure of the working fluid due to changes in the thermal energy of the high-temperature heat medium in which the evaporator is installed, and its volume changes. When the vapor pressure of the working fluid increases, the volume of the non-condensable gas decreases, and the effective length of the condensing section automatically expands by that amount. Conversely, when the vapor pressure of the working fluid decreases, the volume of the non-condensable gas decreases. As the volume increases, the effective length of the condensing section automatically decreases accordingly.

In addition, since the second heat pipe is a gravity-operated heat flow diode heat pipe, the lower side disposed in the heat storage material becomes the evaporation part, and the higher side disposed in the low-temperature heat medium serves as the condensation part. It operates only in bottom heat mode, and does not operate in so-called top heat mode, where the temperature on the low-temperature heat medium side is higher than the temperature on the heat storage material side.

Therefore, in this heat pipe type heat exchanger, when the thermal energy of the high temperature heat medium is sufficiently large, the working fluid is actively evaporated in the evaporation section, so that the vapor pressure of the working fluid in the first heat pipe increases. , the non-condensable gas is compressed to reduce its volume, thereby increasing the effective length of the condensing section of the heat pipe.

As a result, the vapor of the working fluid condenses in the part of the condensing section of the first heat pipe where the heat storage material is not provided, and the heat transferred by the vapor of the working fluid as latent heat of vaporization is used to convert the low-temperature heat medium into By sufficiently heating the working fluid and condensing the vapor of the working fluid at the end of the condensing section where the heat storage material is provided, the heat transported as latent heat of vaporization is accumulated in the heat storage material. At this time, since the temperature of the steam of the heated low-temperature heat medium is higher than the temperature of the heat storage material, the second heat pipe is in the top heat mode and does not operate, so that the heat stored in the heat storage material is not consumed.

On the other hand, when the thermal energy of the high-temperature heat medium decreases, the evaporation of the working fluid decreases, and the working fluid inside the first heat pipe decreases.
l The vapor pressure of the fluid decreases, the non-condensable gas expands and expands its volume, the effective length of the condensing section of the heed pipe decreases, and the heat storage material at the end of the condensing section is provided. The entire area within the condensation zone is filled with non-condensable gas, and this area loses its function as a condensing section. As a result, in the condensing section of the first heat pipe, only the section where the heat storage material is not provided functions effectively as a condensing section, and the vapor of the working fluid is condensed only in this section, and is carried away as latent heat of vaporization. All the heat generated is used only to heat the low temperature heat transfer medium, and no heat is stored in the heat storage material.

Furthermore, even if all the heat received from the high-temperature heat medium is used to heat the low-temperature heat medium, the input thermal energy decreases to the point where the low-temperature heat medium cannot be sufficiently heated. This means that the temperature of the low-temperature heat medium will not rise. As a result, the temperature of the heat storage material becomes higher than the temperature of the heated low-temperature heat medium, so the second heat pipe enters the bottom heat mode and operates as a heat pipe.

Therefore, the heat accumulated in the heat storage material is carried to the part placed in the low temperature heat medium that functions as the condensation part of the second heat pipe, and is used to heat the low temperature heat medium, thereby eliminating the shortage of input thermal energy. , is supplemented by the heat of the heat storage material carried by this second heat pipe, and stable heating of the low-temperature heat medium is achieved.

EXAMPLE Hereinafter, an example in which the heat pipe type heat exchanger of the present invention is applied to a steam generator using waste gas from a gas engine as a heat source will be described with reference to FIGS. 1 to 3.

The heat pipe type heat exchanger 11, which is a steam generator, transports the heat of waste gas H from a gas engine that drives a generator through a heat pipe, heats water, and generates steam. It is divided into three parts: zone A, steam generation zone B, and heat storage zone C. In the waste gas zone A, open gas H, which serves as a heat source, flows, and in steam generation zone B, heated steam is distributed. A water pipe 12 is provided through which the water to be oxidized flows from the bottom to the top, and a heat storage tank 13 filled with pentaerythritol, etc., which acts as a heat storage material at 200'C class, is provided in the heat storage zone C. There is.

In the waste gas zone A, there is a first heat vibrator 14.
The condensing section of the first heat pipe 14 passes through the water pipe 12 of the steam generation zone B adjacent to the waste gas zone A and connects to its end. Heat storage in heat storage zone C on the side! Located in N13, the waste gas zone A side is low, and the heat storage zone C side is low.
It is slightly slanted so that the sides are higher.

This first heat vibrator 14 is a variable conductance type heat pipe, and has a steam generation zone B and a heat storage zone C.
A non-condensable gas 15 is sealed inside the condensing section disposed on the side, and is compressed or expanded according to fluctuations in the vapor pressure of the condensable working fluid in the first heat pipe 14. By changing its volume, the effective length of the condensing section is automatically adjusted. Furthermore, a large number of heat receiving fins 16 are provided around the outer periphery of the evaporator disposed in the waste gas zone A, so that heat can be efficiently received from the waste gas H which is a heat source.

Further, one end of the second heat pipe 17 (the left end in FIG. 1) is arranged in the heat storage tank 13 of the heat storage zone C,
The other end side of this second heat pipe 17 is a steam generation zone B.
The heat storage tank 13 is disposed in the water pipe 12 such that one end of the heat storage tank 13 is lower and the other end of the water pipe 12 is higher.

This second heat pipe 17 is a gravity-operated heat flow diode heat pipe, and one end of the lower side disposed in the heat storage tank 13 serves as an evaporation part, and the other end disposed in the water pipe 12 serves as a condensation part. It operates as a heat pipe only in the so-called bottom heat mode, and a steep slope portion 17a is provided approximately in the center of the entire length to prevent malfunction during the top heat mode.

Next, the operation of this embodiment configured as described above will be explained.

The variable fundductance type first heat pipe 14 receives the heat of the high-temperature waste gas H at the heat receiving fins 16 in the evaporator section disposed in the waste gas zone A, so that the working fluid is heated and evaporated. The working fluid turns into steam and enters the steam generation zone B.
The fluid instantly moves to the condensing section disposed within the heat storage zone C, where it is deprived of latent heat of vaporization, condenses, and returns to a liquid-phase working fluid. At this time, the end side of the condensing part in which the non-condensable gas 15 is sealed is prevented from functioning as a condensing am by the non-condensable gas 15, and only the part without the non-condensable gas 15 has an effective length. It functions as a condensing section. In addition, in the second heat pipe 17 of the gravity-operated heat flow diode heat pipe, in order to move the condensed liquid phase working fluid to the evaporation part by the action of gravity, the lower side disposed in the heat storage zone C is the evaporation part. Therefore, it operates as a heat pipe only in the bottom heat mode in which the higher side disposed in the steam generation zone B becomes the condensing part.

Therefore, in this heat exchanger 11, when the gas engine that drives the generator operates at high output and the heat energy of the waste gas H that is the heat source is large enough, the working fluid in the first heat pipe 14 evaporates. As a result, the vapor pressure of the working fluid increases, compressing the non-condensable gas 15 and reducing its volume, and the effective length of the condensing section increases to 1 (1). (See Figure 2). As a result, the vapor of the working fluid condenses in the condensing section of the first heat pipe 14 provided in the water pipe 12, and the heat transferred by the vapor of the working fluid as latent heat of vaporization causes water to be absorbed. By heating and actively generating steam, the steam of the working fluid is also condensed on the end side of the condensing part provided in the heat storage tank 13 of the first heat pipe 14.
The heat transported as latent heat of vaporization is accumulated in the heat storage tank 13 as surplus heat. At this time, the second heat pipe 17 is
Heat storage l! Since the temperature of the heated steam in the water pipe 12 is higher than the temperature of the heat storage tank 13, the top heat mode is set and the heat storage tank 13 does not operate, so that the heat accumulated in the heat storage tank 13 is not consumed.

On the other hand, when the demand for electricity decreases and the output of the gas engine that drives the generator decreases, the heat density of the waste gas H decreases and the heat input to the heat exchanger 11 decreases. , the evaporation of the working fluid in the first heat pipe 14 is attenuated, the vapor pressure of the working fluid decreases, and the non-condensable gas 15 expands to expand its volume. As a result, the condensing section of the first heat pipe 14 is reduced to the effective length L2, and the portion located in the heat storage zone C on the end side of the condensing section is filled with non-condensable gas 15, and this portion is condensed. lose its function as a department. As a result, in the condensing part of the first heat pipe 14, only the part disposed in the steam generation zone B effectively functions as a condensing part, and the vapor of the produced fluid is condensed only in this part, resulting in evaporation. All of the heat carried as latent heat is used only to heat the water flowing through the water pipe 12, and no heat is accumulated in the heat storage l113.

Furthermore, even if all the heat received from the waste gas H is used to heat water, if the thermal energy of the waste gas H decreases to the point where the required amount of steam cannot be obtained, the steam generation zone B The amount of steam generated decreases and the temperature of the steam decreases. As a result, the second heat pipe 17
The temperature of the heat storage zone C, where the lower side is arranged, becomes higher than the steam temperature of the steam generation zone B, and it becomes a bottom heat mode and operates as a heat pipe (see FIG. 3). Therefore, the heat accumulated in the heat storage tank 13 is transferred to the part disposed in the steam generation zone B that functions as a condensing part of the second heat pipe 17 and heats the water, thereby resolving the lack of thermal energy in the waste gas H. is replenished by the heat from the heat storage tank 13 carried by the second heat pipe 1-4, the necessary amount of steam is secured, and a stable supply of heat (steam) is achieved.

Therefore, the heat exchanger 11 of this embodiment is most suitable as a steam generator for a combined heat/electricity supply system in hotels, hospitals, etc. where a stable supply of heat (steam) is required although the power load fluctuates. be.

As described in detail, the heat pipe type heat exchanger of the present invention includes a variable conductance type first heat exchanger in which a non-condensable gas is enclosed in a container pipe so that it can be compressed and expanded in response to fluctuations in the vapor pressure of a working fluid. A heat pipe, a heat storage material provided on the outer periphery of the end of the condensing part of the first heat pipe, and a gravity-operated heat flow diode heat with one end disposed in the heat storage material and the other end raised. a second heat pipe of the pipe, the evaporating part of the first heat pipe is disposed in the high temperature heat medium, and the part excluding the part where the heat storage material of the condensing part is provided on the outer periphery in the low temperature heat medium; At the same time, the other end of the second heat pipe is placed in the low-temperature heat medium path, so that when the heat source has a sufficiently large amount of thermal energy, the vapor pressure in the first heat vibrator increases. When the volume of the non-condensable gas is reduced and the effective length of the condensing section is expanded, the low-temperature heat medium is heated and excess heat is stored in the heat storage material, and when the thermal energy of the heat source decreases, the first heat pipe The vapor pressure inside the chamber decreases, expanding the volume of non-condensable gas, and the effective length of the condensing section decreases.The input heat is automatically controlled to be used only for heating the low-temperature heat medium, and the high-temperature heat is When the heat energy of the medium is insufficient, the part of the second heat pipe placed in the heat storage material becomes the evaporation part, which becomes the bottom heat mode, and the heat stored in the heat storage material is transferred to the low-temperature heat medium. Stable heating of the low-temperature heat medium can be achieved by transporting it to the location where it is placed and replenishing the lack of thermal energy.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, and FIG. 1 shows a heat exchanger 41! Cross-sectional view, Figure 2 is an explanatory diagram showing a state where the heat source temperature is sufficiently high, Figure 3 is an explanatory diagram showing a state where the heat source temperature has decreased, and Figure 4 is an explanatory diagram showing an example of a conventional combined heat/electricity supply system. It is a diagram. 11... Heat exchanger, 12... Water pipe, 13...
・Heat storage tank, 171...first heat pipe, 15・
...Non-condensable gas, 16...Heat receiving fin, 17.
...Second heat pipe, A...Waste gas zone, B
...Steam generation zone, C...Heat storage zone, H.
...Waste gas, L, Ll, L2...Effective length.

Claims (1)

[Claims] A variable conductance type first heat pipe in which a non-condensable gas is compressed and expanded in response to fluctuations in the vapor pressure of the working fluid at the end of a condensing section in a container pipe in which a condensable working fluid is sealed. A heat storage material provided on the outer periphery of the end of the condensing part of the first heat pipe, and a gravity-operated heat flow diode heat pipe with one end disposed in the heat storage material and the other end raised. a second heat pipe, the evaporation part of the first heat pipe being disposed in a high temperature heat medium;
and a portion of the condensing section excluding a portion where the heat storage material is provided on the outer periphery is disposed in the low-temperature heat medium, and the other end side of the second heat pipe is disposed in the low-temperature heat medium. A heat pipe type heat exchanger.