JP2001248991A - Heat transfer pipe and heat transferring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-transferring pipe where a heat-transferring characteristic at a heat exchanger is not decreased as compared with that of the prior art using water-based heat transferring medium when viscous and resilient liquid solution of surface-active agent is used as heat transferring medium while an area of a heat transferring part of a heat exchanger is being kept same as that of the prior art. SOLUTION: There is provided a heat transferring pipe 12 of a heat exchanger where liquid solution of surface active agent is used as heat transferring medium and a rod-like filling material 13 is inserted along an inner central axis of the heat transferring pipe 12 where the heat transferring medium flows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing flow friction by adding a surfactant to water in a system for transferring cold and warm heat by sensible heat of water. The present invention relates to a heat exchanger tube for a heat exchanger that simultaneously prevents a decrease in heat transfer performance and a heat transfer system using the same.

[0002]

2. Description of the Related Art For example, in a district heating and cooling system,
The length of pipes for circulating water as a heat transfer medium from the heat supply side plant to the heat use side building is several kilometers or more, the water transfer power is considerably large, and the running cost of the district heating and cooling system is about 60%. % To 70%.

[0003] Recently, as an effective method for reducing the water transfer power, a method has been proposed in which an aqueous surfactant solution exhibiting viscoelasticity is used as a heat transfer medium to significantly reduce the flow friction resistance.

[0004] When a specific cationic surfactant and a counter ion such as sodium salicylate of several tens to several thousand ppm are dissolved in water flowing in a pipe, the surfactant is concentrated in the water around the hydrophobic base in water. It is said that the hydrophilic base is arranged on the outer periphery to form micelles (associates), and the micelles are rod-shaped and entangled in higher order to exhibit viscoelasticity.

As a method of reducing the frictional resistance in a surfactant and a water transfer pipe exhibiting such characteristics, for example, Japanese Patent Publication No.
-76360, JP-B-4-6231, JP-B5-475
34, and JP-A-8-31431.

[0006] However, it is known that the characteristics of these aqueous solutions are such that the heat transfer characteristics are also reduced at the same time as the flow friction resistance is reduced. In other words, when considering the use of these aqueous solutions for heat transfer systems such as district heating and cooling, building air conditioning, etc., the flow friction resistance is certainly reduced, and the transfer power is also reduced accordingly, creating an energy-saving heat transfer system. However, on the other hand, the heat transfer performance of the heat exchangers installed in the heat supply-side plant and the heat utilization-side air conditioner will be reduced.
Therefore, as compared with a conventional system using a water or an aqueous solution in which additives for preventing corrosion of equipment materials such as pipes are dissolved as a heat transfer medium (hereinafter referred to as a conventional heat transfer system), the heat supply side plant and heat It is necessary to increase the area of the heat transfer portion of the use side heat exchanger.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous viscoelastic surfactant solution which is used as a heat transfer medium.
A heat transfer tube and a heat transfer tube using the same, in which the area of the heat transfer portion of the heat exchanger section is the same as that of the conventional type, and the heat transfer characteristics of the heat exchanger section are not reduced as compared with the case of using the conventional aqueous heat transfer medium. It is to provide a system.

[0008]

Means for Solving the Problems The inventors of the present invention provide a heat transfer system using a viscoelastic surfactant aqueous solution as a heat transfer medium to transfer heat to the heat transfer medium in a heat supply side plant. Heat exchanger (heats or cools the heat transfer medium) and transfers heat from the heat transfer medium in the heat utilization side plant (heats or cools the heat transfer medium)
Regarding heat exchangers, the above object is achieved by inserting a rod-shaped filler into heat transfer tubes used in the heat exchangers along a central axis inside the tubes through which the heat transfer medium flows. I found that.

That is, the present invention provides a heat transfer tube and a heat transfer system using the same as described below. Item 1. A heat transfer tube for a heat exchanger using a surfactant aqueous solution as a heat transfer medium, wherein a rod-shaped filler is inserted along a central axis inside the tube through which the heat transfer medium flows. Item 2. A heat transfer system that uses a surfactant aqueous solution as a heat transfer medium, a heat supply-side plant that supplies heat to the heat transfer medium, a heat-use-side plant that uses heat of the heat transfer medium, A pipe that circulates the heat transfer medium between a heat supply-side plant and the heat utilization-side plant, wherein at least one of the heat supply-side plant and the heat utilization-side plant has the heat transfer tube according to item 1. Heat transfer system with exchanger.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The heat transfer performance of a viscoelastic surfactant aqueous solution varies greatly depending on the processed shape inside a heat transfer tube. When the rod-shaped filler is inserted along the central axis inside the heat transfer tube through which the viscoelastic surfactant aqueous solution flows, for example, the refrigerator actually used in the heat supply side plant of the district cooling and heating system With a pipe diameter (inner diameter) of 10 to 20 mm and a flow velocity range of 1 to 2 m / s that is actually used, the same heat transfer performance as that of conventional water conveyance (heat transfer pipe) Transmission).

As described above, when the rod-shaped filler is inserted along the central axis inside the heat transfer tube, the heat transfer performance does not decrease even when the viscoelastic surfactant aqueous solution is used as the heat transfer medium. It is considered that the insertion of the rod-shaped filler increases the flow velocity inside the heat transfer tube even when the heat transfer medium flows at the same flow rate.

The cross-sectional shape of the rod-shaped (column-shaped) filler in the heat transfer tube of the present invention is not particularly limited.
For example, a circle, a quadrangle, a triangle, a semicircle, and the like can be given.
Preferably, it is circular or the like.

The cross-sectional area of the rod-shaped filler is not particularly limited, either.
%, More preferably 10 to 80%, particularly preferably 15 to 70%.

Furthermore, the length of the rod-shaped packing is not particularly limited, and it is not necessary to insert the rod-shaped packing over the entire length of the heat exchanger heat transfer tube. It is preferable that the heat transfer tube is inserted into the upstream side of the heat transfer tube at a length of 5 to 100% of the total length of the heat transfer tube, more preferably 10 to 100%.
Particularly preferably, the length is 40 to 100%.

The material of the rod-shaped filler is not particularly limited, but is preferably a synthetic resin or a metal. Examples of the synthetic resin include an acrylic resin, polyvinyl chloride, a melamine resin, and polyethylene, and an acrylic resin and polyethylene are preferable. Examples of the metal include iron, copper, gold, silver, stainless steel, brass, and the like.
Stainless steel is preferred.

The rod-shaped packing is fixed while being inserted inside the heat transfer tube. Although the fixing means is not particularly limited, for example, it may be fixed by using several rod-shaped fixing members having a smaller diameter than the rod-shaped filler so as to connect the inner surface of the heat transfer tube and the outer surface of the rod-shaped filler. .

The surfactant contained in the aqueous surfactant solution used as the heat transfer medium is not particularly limited, and may be those conventionally used. For example, oleyl-bis (2
-Hydroxyethyl) methylammonium salicylate, cetyltrimethylammonium salicylate, stearyltrimethylammonium salicylate, and the like.

The concentration of the surfactant in the aqueous surfactant solution is not particularly limited either, but is preferably 50 to 50,000 ppm, more preferably 50 to 10,000 ppm, and more preferably 50 to 50 ppm.
00 ppm is particularly preferred.

The heat transfer tube of the present invention is used for heat transfer of a district cooling / heating system or a building air conditioning system, transfer of waste heat from a garbage incineration plant or a factory, or transfer of temperature difference energy such as river water, seawater, and sewage treatment water. When used, not only the water transfer power is reduced by reducing the flow frictional resistance of the viscoelastic surfactant aqueous solution, but also heat is transferred to the heat transfer medium in the heat supply side plant and the heat utilization side plant, respectively. It is not necessary to increase or improve the heat exchanger to be used, and it is possible to use a conventional water exchanger.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, as an example of a heat exchanger used in a heat transfer system, a structure of a refrigerator in a heat supply plant of a district heating and cooling system will be described.

The portion for transmitting the cold generated in the refrigerator to the heat transfer medium is generally called an evaporator, and is constituted by a shell and tube type heat exchanger as shown in FIG. As shown in FIG. 1, the heat exchanger 10 includes a shell 11 and a heat transfer tube 12. The inside of the shell is kept under reduced pressure, and a number of heat transfer tubes (tubes) 12 are installed in parallel in a certain direction. While the heat transfer medium continuously flows inside each heat transfer tube 12, water in the case of the absorption refrigerator and Freon liquid in the case of the electric turbo refrigerator are continuously flowing in the shell 11 respectively. And the liquid evaporates (evaporates) while dripping on the outside of the heat transfer tube 12. The heat transfer medium in the heat transfer tube 12 is cooled by the heat of vaporization at that time.
The cooled heat transfer medium is pumped through piping
It is supplied to the heat utilization side and is used as cooling heat for cooling.

FIG. 2 is a diagram showing a configuration of an evaluation device for evaluating the heat transfer characteristics of the heat transfer tube. As shown in FIG.
The heat transfer medium adjusted to 10 ° C. is filled in the medium tank 21, and the heat transfer medium in the medium tank 21 is introduced into the heat transfer characteristic measuring unit 26 via the pipes 23 to 25 by the pump 22. The heat transfer characteristic measuring unit 26 includes the heat transfer tube 12 and the heat transfer tube 12.
And a circular pipe 27 covering the periphery of the circular pipe. The circular pipe 27 is a circular pipe made of stainless steel and having a nominal diameter of 40A. Heat transfer tube 12 and circular tube 2
7, inside a double tube (double tube heat exchanger)
That is, in the annular portion between the circular tube 27 and the heat transfer tube 12,
About 2 to 3 so that the temperature of the tube wall of the heat transfer tube 12 becomes 8 ° C.
° C cold water is constantly introduced. This cold water allows the heat transfer tube 1
2 is cooled. In order to measure the pressure loss of the heat transfer medium flowing through the heat transfer tube, holes 28 and 29 having a diameter of 2 mm were provided at both ends of the double tube heat exchanger.
And connect a differential pressure gauge.

With the above configuration, the present evaluation apparatus calculates the heat transfer coefficient as the heat transfer characteristic inside the heat transfer tube 12 during cooling and the pressure loss as the flow characteristic. Note that the method of cooling the heat transfer medium flowing in the heat transfer tube differs between the actual evaporator in the refrigerator and the evaluation device, but they are all related to the outside of the heat transfer tube, and the method of cooling the heat transfer tube discussed in the present invention. There is no effect on the heat transfer characteristics (heat transfer coefficient) of the heat transfer medium flowing inside.

As a heat transfer medium to be tested, as a conventional type, 750 ppm of Kurisawa I-108 (manufactured by Kurita Kogyo Co., Ltd.), which is a nitrite-based pipe corrosion rust preventive, was dissolved in tap water (hereinafter, referred to as "heat transfer medium"). As a flow resistance reducing type, a surfactant mainly containing oleyl-bis (2-hydroxyethyl) methylammonium chloride in the above-mentioned conventional heat transfer medium (conventional solution): Esocard O-12 (manufactured by Lion) and sodium salicylate (manufactured by Wako Pure Chemical Industries) at 750 ppm and 450 ppm, respectively.
Dissolved (hereinafter referred to as frictional resistance reducing aqueous solution, Drag
Reduction = DR solution).

Example 1 As a heat transfer tube of the above-described evaluation device, an acrylic resin rod-like filler having a diameter of 6 mm was inserted along only the inner central axis of a smooth copper tube having an inner diameter of 14 mm into only 40% of the upstream portion of the tube. The fixed one was used.

FIG. 3 shows a cross-sectional view of the heat transfer tube 12. FIG. 4 is a cross-sectional view (longitudinal cross-sectional view) of the upstream portion of the heat transfer tube 12 in the longitudinal direction. In the figure, reference numeral 13 denotes a rod-like packing. Reference numeral 14 denotes a fixing member for fixing the rod-shaped filler 13 inside the heat transfer tube 12. In the figure, three rod-shaped fixing members 14 smaller in diameter than the rod-shaped filler 13 are provided radially, and the inner peripheral surface of the heat transfer tube 12 and the outer peripheral surface of the rod-shaped filler 13 are connected to form a rod-shaped filler. 13 is fixed inside the heat transfer tube 12.

The heat transfer tube was installed in the apparatus, and the pressure loss and the heat transfer coefficient of the DR solution were measured.

Comparative Example 1 A smooth copper tube having an inner diameter of 14 mm was used as a heat transfer tube of the above-described evaluation apparatus.

This heat transfer tube was installed in the apparatus, and the pressure loss and the heat transfer coefficient of the conventional solution and the DR solution were measured, respectively.

FIG. 5 shows the pressure loss and the heat transfer coefficient of the conventional solution and the DR solution in each of the heat transfer tubes thus obtained.

In FIG. 5, the black triangles indicate the results of the DR solution of the heat transfer tube with the rod-shaped filler inserted, the black circles the results of the DR solution of the heat transfer tube without the inserted rod-shaped filler, and the white circle indicates the conventional heat transfer tube without the rod-shaped filler inserted. The results for the mold solutions are shown respectively. As is clear from the figure, the flow velocity range in the actual machine is 1-2 m /
In s, in the heat transfer tube without the rod-shaped filler inserted, the pressure loss of the DR solution is reduced at the same flow rate, and the heat transfer coefficient is lower than that of the conventional solution. However, the heat transfer coefficient of the DR solution in the heat transfer tube with the rod-shaped filling is not lower than that of the conventional solution in the heat transfer tube without the rod-shaped filling. That is, it was found that even when the DR solution was used, the heat transfer characteristics could be prevented from being reduced without increasing the pressure loss in the rod-shaped filler-inserted heat transfer tube as compared with the conventional type.

[0032]

According to the heat transfer tube of the present invention, when an aqueous solution of a viscoelastic surfactant is used as a heat transfer medium, the area of the heat transfer portion of the heat exchanger section is made the same as that of the conventional type, and The heat transfer characteristics in the heat exchanger section do not decrease as compared with the case where the heat transfer medium is used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a shell and tube heat exchanger.

FIG. 2 is a diagram illustrating a configuration of an evaluation device for evaluating heat transfer characteristics of a heat transfer tube.

FIG. 3 is a cross-sectional view showing one example of the heat transfer tube of the present invention.

FIG. 4 is a longitudinal sectional view (longitudinal sectional view) showing an example of the heat transfer tube of the present invention.

FIG. 5 is a diagram showing pressure loss and heat transfer coefficient in Examples and Comparative Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Heat exchanger 11 ... Shell 12 ... Heat transfer tube 13 ... Bar-shaped packing 14 ... Fixing member 21 ... Medium tank 22 ... Pump 23, 24, 25 ... Piping 26 ... Heat transfer characteristic measuring part 27 ... Circular pipe 28, 29 ... hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Yoshikawa 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Hiroki Usui 2-86 Gyokicho, Itami-shi, Hyogo Prefecture (72) Inventor Kazuo Onojima 4-640 Shimoseito, Kiyose-shi, Tokyo Inside Obayashi Corporation Technical Research Institute (72) Inventor Yoshio Gomachi 4-33 Kitahama Higashi, Chuo-ku, Osaka-shi, Osaka F-term (Obayashi Gumi head office) Reference) 3L054 BF20

Claims (2)

[Claims] 1. A heat transfer tube for a heat exchanger using a surfactant aqueous solution as a heat transfer medium, wherein a rod-shaped filler is inserted along a central axis inside the tube through which the heat transfer medium flows. . 2. A heat transfer system using a surfactant aqueous solution as a heat transfer medium, a heat supply side plant for supplying heat to the heat transfer medium, and a heat use side plant using heat of the heat transfer medium. And a pipe for circulating the heat transfer medium between the heat supply-side plant and the heat utilization-side plant, wherein at least one of the heat supply-side plant and the heat utilization-side plant is according to claim 1. A heat transfer system provided with a heat exchanger having the heat transfer tubes.