JPH02192594A - Heat syphon type heat exchanger - Google Patents

Abstract

PURPOSE:To unify heat transfer performance in the lengthwide direction of a heat transfer tube by a method wherein two rows or more of heat transfer tubes for promoting the operation of operating liquid in the upper or lower part of a system are arranged and one part of the tubes is used as going tubes while remaining tubes are used as returning tubes. CONSTITUTION:Upper heat transfer tubes are arranged in two rows 3a1, 3a2 and lower heat transfer tubes are arranged in two rows 3c1, 3c2 while one end of the tubes is turned to use the heat transfer tubes in the row 3a1 as a going tube and use the other heat transfer tube in the row 3a2 as a returning tube. The uneven property of performances at the inlet side and the outlet side of the heat transfer tube is improved remarkably and unified heat transfer performance may be shown along the whole length of the heat transfer tube. As a result, the adhering degree of ice upon space cooling operation is equalized in the lengthwise direction of the heat transfer tube, whereby ice 6 may be frozen with the same growing speed along the whole length of the tube. The same thing may be said in space heating operation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat siphon type heat exchanger, and in particular, to a heat siphon heat exchanger in which a heat exchanger is arranged in a longitudinal direction of a heat exchanger tube in order to promote condensation or evaporation of a working fluid. The present invention relates to a tosiphon type heat exchanger that uniformizes the heat transfer performance in the heat exchanger so that the operation of the entire system is performed evenly.

[Conventional technology] In an air conditioning system for heating and cooling, a heat storage water tank is installed, a refrigeration cycle is operated using late-night electricity, etc., and heat is stored in the form of ice or hot water in the heat storage water tank and used during air conditioning. There is a method that greatly improves the economic efficiency of air conditioning by releasing the stored heat.

For such heat storage, a heat pipe was used - a tosiphon heat exchanger was submerged in water, and the heat transfer efficiency was greatly improved due to the isothermal properties of the heat pipe - a tobipe heat storage water tank was proposed. I'm here.

FIGS. 12(a), 12(b), and 13 are explanatory diagrams showing the specific structure of such a pipeless heat storage water tank device.

The device includes a heat storage water M1 filled with heat transfer water 2, and a heat siphon type heat exchanger 3 submerged in a heat storage water tank 1.
, compressor 4a, heat exchanger (operates as a condenser when storing ice heat, and as an evaporator when storing hot water heat +4)
The refrigeration cycle 4 consists of a WB tension valve 4c, and piping 4d.

As shown in the cross-sectional view of FIG. 12(b), the heat siphon heat exchanger 3 includes an upper sheath tube 3b having an upper heat exchanger tube 3a therein, and a lower sheath tube 3d having a lower heat exchanger tube 3C therein.
and a plurality of heat exchangers 3e connecting the upper sheath pipe 3b and the lower sheath pipe 3d constitute one sealed space,
The closed space contains a working fluid 5 (liquid and vapor) such as Freon.
is included.

During ice storage, the compressor 4a, heat exchange tube 4b
(acts as a capacitor in this case).

The refrigeration cycle 4, which includes an expansion valve 4c and piping 4d, is piped as shown in FIG. At this time, the upper heat exchanger tube 3a operates as an evaporator of the refrigeration cycle 4. On the other hand, the lower heat exchanger tube 3C is closed by a closing means (not shown) and separated from the refrigeration cycle 4. In this state, the refrigerant gas which has been compressed to a high temperature by the compressor 4a of the refrigeration cycle 4 is guided to the heat exchange tube 4b, where it comes into contact with the atmosphere, is cooled by heat radiation, and is condensed. This condensed refrigerant gas is sent to the upper heat transfer tube 3a of the heat siphon type heat exchanger 3 via the expansion valve 4C. At this time, the upper heat exchanger tube 3a acts as an evaporator, and the refrigerant gas takes vaporization heat from the surface of the upper heat exchanger tube 3a and evaporates. On the other hand, the working fluid 5 evaporated by the heat of the water 2 undergoes heat exchange around the upper heat transfer tube 3a and the upper sheath tube 3b and is compressed. At this time, the upper heat exchanger tube 3
The condensed ill liquid 5a condensed around the tube a falls as droplets as shown in FIG.
b. As a result, the condensed liquid 5a flows from the upper heat exchanger tube 3a to the upper sheath tube 3b and the heat exchange tube 3e, and the
As shown in the figure, the condensed working fluid 5a is not passed through the heat exchange tube 3e.
Ice 6 gradually grows around the tosiphon heat exchanger 3 as shown in FIG. 11. To go.

On the other hand, during hot water heat storage, the refrigeration cycle 4 consisting of the compressor 4a, heat exchange pipe 4b (operating as an evaporator in this case), expansion valve 4c, and piping 4d:
It is piped as shown in FIG. 13 and connected to the lower heat transfer tube 3C of the heat siphon type heat exchanger 3. At this time, the lower heat exchanger tube 3c operates as a condenser of the refrigeration cycle 4. At this time, the upper sheath tube 3b is closed by a closing means (not shown) and separated from the refrigeration cycle 4. In this state, the refrigerant supplied from the refrigeration cycle 4 condenses in the lower heat exchanger tube 3c, and the working fluid 5 evaporates due to the condensation, and is cooled by the water 2 via the heat exchange tube 3e and the upper sheath tube 3b. and condense it. Due to the condensed heat dissipation at this time, the water 2 in contact with the heat exchange pipe 3e and the upper sheath pipe 3b
is heated.

In this way, ice heat storage for cooling (use of latent heat) and hot water heat storage for heating (use of sensible heat) are efficiently performed by the syphon type heat exchanger in one heat storage water tank.

[Problems to be Solved by the Invention] All heat transfer tubes used in conventional heat siphon heat exchangers are single tubes, and the performance of the refrigerant flowing inside the tubes varies in the longitudinal direction of the tubes.

That is, FIGS. 8 and 9 are explanatory diagrams showing the enthalpy and heat transfer coefficient of evaporation and condensation of heat transfer tubes in a heat siphon type heat exchanger having a conventional configuration. As can be seen, as evaporation is promoted in the tube and the two-phase flow of liquid + vapor moves from the inlet side to the outlet side of the heat pipe, the vapor dryness X in the tube improves, and the heat transfer performance in the tube improves. do.

(The higher the dryness of the refrigerant vapor, the better the evaporation performance.) As a result, a difference in performance occurs between the inlet and outlet sides of the heat exchanger tubes of the heat exchanger, or between the rows of multiple groove pipes.
As shown in FIG. 4, the icing 6 on the inlet side of the heat exchanger tube 3a is small, and the icing 6 becomes larger toward the outlet side, resulting in a large difference in the degree of icing. Recently, in order to make the heat storage tank more compact, the arrangement pitch of the heat exchange tubes has been made as small as possible, and the above phenomenon has become even more noticeable, causing problems such as insufficient ice making speed.

This is true not only during cooling operation but also during heating operation, and as can be seen from Figures 8 and 9, as heat exchange progresses, the evaporation performance in the lower sheath pipe decreases, and the hot water temperature in the tank decreases. In addition, the performance of the lower heat transfer tube is severely limited due to the minimization of the pitch between the heat transfer tubes due to the compactness of the tank, and the required amount of heating is reduced. Time is no longer available.

It is an object of the present invention to solve the problems of the prior art as described above, and to improve the heat transfer performance in the longitudinal direction of heat transfer tubes arranged to promote condensation or evaporation of the working fluid of a heat siphon heat exchanger. The purpose of the present invention is to provide a heat siphon type heat exchanger in which the operation of the entire system is made uniform.

[Means for Solving the Problem] The present invention performs heat exchange using sensible heat or latent heat by sealing a working fluid and causing movement based on evaporation and condensation of the working fluid. In a type heat exchange system, two or more rows of heat transfer tubes are arranged in the upper or lower part of the system to promote the operation of the working fluid, and some of the tubes are used as outgoing pipes and the remaining tubes are used as return pipes. Features [Function] When there is a difference in heat transfer performance in the longitudinal direction of a heat transfer tube and the heat transfer performance gradually changes from the inlet side to the outlet side of the tube, it is possible to When installed in a piping state, the heat transfer performance of each round trip of the pipe is arithmetic averaged, and the performance is made uniform over the entire length.

[Example] The present invention will be described below with reference to Examples.

1 and 2 are explanatory diagrams showing an embodiment of the heat siphon type heat exchanger 3 according to the present invention, in which FIG. 1 shows the cooling operation and FIG. 2 shows the heating operation, respectively. This shows that.

In this example, the upper heat exchanger tube is 3a! and 3az
The lower heat exchanger tubes are arranged in two rows of 3cs and 3C2, respectively, and one end of the tubes has a folded structure as shown in Figure 3. The pipe 3a1 is used as an outgoing pipe, and the other pipe 3az is used as a returning pipe. (Same for the lower heat exchanger tube) 6th
7 are explanatory diagrams showing the enthalpy and heat transfer coefficient during evaporation and condensation of the heat exchanger tubes of the heat exchanger according to the present invention arranged as described above. As is clear from the comparison with the conventional example shown in Figures 8 and 9, the non-uniformity of performance on the inlet and outlet sides of the heat transfer tube has been greatly improved, and the heat transfer performance has been made uniform over the entire length. It is clear that this shows that

As a result, the degree of icing during cooling operation becomes the same in the longitudinal direction, and as shown in FIG. 3, the ice 6 can be frozen at the same growth rate throughout. The same can be said for heating operation, which homogenizes the hot water in the tank and, in combination with the preheating effect of the return pipe, enables rapid heating.

FIG. 5 is a sectional view showing the arrangement of heat transfer tubes in the upper and lower sheath tubes 3b and 3d, and FIG. 5(a) shows two rows of heat transfer tubes 3ax and 3az in the upper sheath tube 3b. The same (b) shows two rows of heat transfer tubes 3C1, 3C2 in the lower sheath pipe 3d, and the same (c) shows three rows of heat transfer tubes 3C1, 3C2, 3c3 in the lower part.
The figure shows how they are arranged and operated by forming reciprocating paths.

Regarding the number of heat exchanger tubes arranged, the above-mentioned 2 rows or 3 rows
The heat exchanger tubes are not limited to just one row, but if the heat exchanger tubes are arranged in multiple rows, the evaporation performance will increase accordingly, and the secondary effect of contributing to the compactness of the heat exchanger can be expected.

[Effects of the Invention] As described above, according to the heat exchanger #A according to the present invention, the heat transfer performance in the longitudinal direction of the array of heat pipes or between rows is made uniform, and furthermore, the evaporation performance of the heat transfer tubes is increased. It has great industrial value, such as improved efficiency and the resulting downsizing of the entire device.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the operating status of the embodiment according to the present invention, Figure 3 shows the icing status of the heat exchanger according to the present invention, and Figure 4 shows the icing status of the conventional example. Explanatory drawings, FIG. 5 is a cross-sectional view showing the piping situation of the heat exchanger tube according to the present invention, FIGS. 6 and 7 are the heat exchanger according to the present invention, and FIGS. 8 and 9 are the conventional examples of evaporation and condensation, respectively. An explanatory diagram showing enthalpy and heat transfer coefficient, Fig. 10 is an explanatory diagram showing a heat siphon type heat exchanger submerged in a tank, and Fig. 11 shows the state of icing on the heat exchanger in Fig. 10. The explanatory diagrams shown in FIGS. 12 and 13 are explanatory diagrams for explaining the operation of the heat pipe type heat storage water tank. 1: 2: 3: 3al, 3az: 3b: 3Cs, 3C2, 3C3: 3d: 3e: 5: 5a: 5b26: Heat storage water tank, water, heat siphon heat exchanger, upper heat exchanger tube, Upper sheath tube, lower heat transfer tube, lower sheath tube, heat exchange tube, working fluid, condensate, evaporated gas, ice.

Claims (2)

[Claims] (1) A heat exchange tube is placed between the upper sheath tube and the lower sheath tube,
In a heat syphon type heat exchanger that seals the working fluid inside these spaces and causes a phase change based on evaporation and condensation of the working fluid, heat is exchanged using the sensible heat or latent heat. A heat syphon type heat exchanger in which two or more rows of heat transfer tubes are arranged to promote the operation of the working fluid, some of the tubes are used as outgoing tubes, and the remaining tubes are used as return tubes, (2) A heat exchange tube is placed between the upper sheath tube and the lower sheath tube,
In a heat syphon type heat exchanger that seals the working fluid inside these spaces and causes a phase change based on evaporation and condensation of the working fluid to exchange heat using the sensible heat or latent heat, A heat syphon heat exchanger in which two or more rows of heat transfer tubes are arranged to promote the movement of the working fluid, with some of the tubes serving as outbound tubes and the remaining tubes serving as return tubes.