JPS5912288A - Heat-transferring device - Google Patents

Abstract

PURPOSE:To supply heat stably and safely even at a high temperature, by adopting n-perfluorohexane (n-PFH) as a working fluid. CONSTITUTION:Since n-PFH is a noncombustible substance, when it is used as a working fluid in a direct fired type heat-transferring device, there is little danger of flaming if the fluid should leaks out to the exterior of the system. In addition, since the freezing point of n-PFH is -86 deg.C, there isno fear of freezing even in cold climatic conditions, and since n-PFH is liquid at normal temperature, it can be easily charged into the heat-transferring device. The maximum temperature at which the device can be operated by using n-PFH in the presence of copper, iron, oils or the like is 250 deg.C, and in that condition, no change was observed in the purity of n-PFH. Further, corrosion quantity of the coexistent metal was little (for copper, about 0.001mm.&hear at 200 deg.C), and generation of hydrogen fluoride did not occur. Accordingly, thermal efficiency can be enhanced and useful life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention is directed to a sealing method for a working fluid that circulates between a regeneration section that heats and evaporates the working fluid and a condensation section that cools and liquefies the working fluid. The present invention relates to a heat transfer device that forms a circulation system and sends thermal energy given to a working fluid in a regeneration section to the outside of the closed circulation system from a condensation section, and can be used, for example, as a heating device.

(b) Background Art Heat pipes and thermosiphons are known as representative examples of this type of heat transfer device, and their working fluids also contain various substances such as water, ethanol, and fluorocarbons. Conventionally known.

However, conventional heat transfer devices using water, ethanol, CFCs, mercury, sodium, cesium, pentane, heptane, etc. as working fluids have poor thermal stability under high temperature conditions depending on the type of working fluid. , equipment structural materials (
Items that are highly corrosive to metal materials (primarily iron, copper, aluminum, etc.), items that are toxic to the human body or have a risk of explosion, items that have a high freezing point (items that are unsuitable for use in cold climates, or items that are expensive) There are various drawbacks such as:

In addition, heat supply methods to the regeneration section of this type of heat transfer equipment include those using electric heaters, steam, oil burners, and gas burners, but among these, the most efficient (the equipment is simple and compact) is used. Generally, a direct flame method is employed, which can be used in a direct fire manner, and in this direct fire method, problems arise particularly in terms of thermal stability of the working fluid under high temperature conditions, corrosiveness to the structural materials of the device, and safety.

(c) Purpose of the Invention The present invention has been made to solve the above-mentioned problems of the prior art. By using a new material with physical properties such as low corrosivity to materials (metals such as iron and copper), it is possible to stably and safely supply heat to the load even under high-temperature conditions such as an open flame method. A heat transfer device is provided.

B) Features of the Invention The feature of the present invention is that n-barfluorohexane (hereinafter referred to as n-PF) is used as the working fluid of this type of heat transfer device.
It is abbreviated as H. ).

(E) Disclosure of the Invention FIG. 1 is a schematic diagram of a heat transfer device to which the present invention is applied;
FIG. 2, FIG. 3, and FIG. 4 show characteristic diagrams of vapor pressure, latent heat of vaporization, and liquid density with respect to temperature of n-PFH, respectively.

Table 1 shows the physical properties of n-PF (used as the working fluid of the heat transfer device).

<Table 1> n-PFH belongs to nonflammable substances, and is a working fluid with little danger of causing a flame even if the working fluid of a heat transfer device using an open flame method leaks out of the system. Also, n −P
FH has a freezing point of 186°G, so there is no fear of the working fluid freezing even in cold climates. Moreover, since it is a liquid at room temperature, it is easy to fill it into the working fluid circulation system of the heat transfer device.

Next, the maximum operating temperature at which n-P F H can be operated as a working fluid in the coexistence of copper, iron, and oil for a long time is determined by data obtained from a comparative experiment with fluorocarbon-based working fluids such as Freon-22. It is shown in Table 2.

<Table 2> Since fluorinated hydrocarbon-based working fluids have superior stability compared to other organic compounds, they are used as working fluids for thermosiphons and heat vibrators. However, as is clear from Table 2, the maximum temperature that can be operated for a long time under conditions where copper, iron, oil, etc. coexist is the highest for fluorocarbon-based working fluids, and is less than 150°C. On the other hand, n-P F H used in the present invention had a good temperature of 250° C., and no change in the purity of n-P F H was observed. In addition, the amount of corrosion of metals that coexist with n-PFH is small (approximately 0.0O1ii/year for copper, a product of 40°G
), no hydrogen fluoride was generated as a result of the experiment.

Based on the physical properties of n-PFH and experimental measurement data as described above, we focused on the fact that low PFH is a suitable working fluid for this type of heat transfer device, and conducted experiments using a heat transfer device (thermosiphon) shown in Figure 1. As a result, the working fluid formed a stable closed circulation cycle in the open flame type, and a higher (several percent) improvement in heat transfer was achieved than in conventional systems.

Next, the system of the heat transfer device using n-PFH as the working fluid will be explained with reference to Fig. 1. (1) is the regeneration section, (2)
is the condensing part, and (3) is the liquid storage part, and these are the pipes (4)
, (5) and (6) to form a closed circulation system (7) for working fluid, and n-PFH is used as the working fluid.

Thus, the working fluid heated in the regeneration section (1) evaporates,
It passes through the pipe (4) as indicated by arrow A and reaches the condensing section (2). The working fluid that has reached the condensing section (2) gives thermal energy (latent heat of vaporization and sensible heat energy) to the load side outside the system (7), and is condensed and liquefied to the piping (5) as shown by the arrow.
) and returns to the regeneration unit (1) via the storage unit (3) and piping (6), and the working fluid circulates through the system (7).

In this way, the thermal energy of the working fluid is transferred to the condensing section (2
) is continuously supplied to the load side.

As described above, the present invention forms a closed circulation system for the working fluid that circulates between the regeneration section and the condensation section, and sends the thermal energy given to the working fluid in the regeneration section from the condensation section to the outside of the system. In a heat transfer device, the working fluid has n −P F
Since it uses H, the stability of the working fluid can be maintained over a long period of time even if the heat source supply method to the regeneration section is a direct fire type, and there is little corrosion of the structural materials of the equipment, making it safe. , the entire device can be made compact, has high thermal efficiency, excellent heat transfer characteristics, and can extend the life of the device. In addition, since n-P F L (does not catch fire or burn, there is little risk of a fire even if liquid leaks, and its freezing point is as low as -86.0°C, making it suitable for use in extremely cold regions. It is also possible to apply this method to household heating equipment, which is extremely useful in practice.

[Brief explanation of the drawing]

Each of the figures relates to one embodiment of the present invention, and the first
The figure is a schematic system diagram of the heat transfer device, Figures 2, 3, and 4.
The figures are characteristic diagrams of vapor pressure, latent heat of vaporization, and liquid density with respect to temperature of n-PFH used in the present invention. (1)... Regeneration section, (2)... Condensation section, (7)...
- Closed circulation system.

Claims (1)

[Claims] (1) A closed circulation system for working fluid is formed that circulates between a regeneration section that heats and evaporates the working fluid and a condensation section that cools and liquefies the working fluid, and the thermal energy given to the working fluid in the regeneration section is recovered. 1. A heat transfer device configured to send heat out of a closed circulation system from a condensing section, characterized in that the working fluid is made of n-perfluorohexane.