JPS6346345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a refrigerant-to-water heat exchanger that undergoes a phase change, such as a condenser of a refrigerator.

Conventional structure and its problems Conventional water-cooled condensers include a double-tube heat exchanger as shown in Figure 3, and a 4-tube heat exchanger designed to improve its performance.
There are modified double-tube heat exchangers as shown in the figure, double-wall heat exchangers with parallel water tubes and refrigerant tubes as shown in Figure 5, and shell-and-tube heat exchangers (not shown). .

However, since these all use tube materials as components, it is difficult to make the heat transfer area denser due to the shape and configuration of the tube materials, or to make the heat exchanger itself smaller and lighter to save resources. It was difficult.

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks of the conventional heat exchanger. The aim is to achieve a smaller size and higher performance.

Structure of the Invention In order to achieve this object, the heat exchanger of the present invention is provided with a large number of heat transfer fins with flow holes arranged on the inner and outer surfaces of a heat transfer cylinder to form a flow path for two fluids for heat exchange,
The condensing fluid is passed through one side, and the condensing fluid side is composed of heat transfer fins with a large open area ratio on the lower side.

With this configuration, in each flow path of the fluid to be heat exchanged, unlike a conventional heat exchanger using a tube material, the heat transfer surface can be configured widely and densely, and the boundary when the fluid passes through the flow holes of the heat transfer fins. The heat transfer coefficient is greatly improved by the layer leading edge effect, the expansion/contraction of the flow as it passes between the heat transfer fins, and the agitation turbulent flow effect due to collision. By promoting removal and reducing the thickness of the liquid film on the heat transfer surface, the condensing heat transfer coefficient is further improved, making it possible to achieve a smaller size and higher performance heat exchanger.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIGS. 1 and 2 showing one embodiment thereof. FIG. 1 is a sectional view of the overall configuration, and FIG. 2 shows the heat transfer fins on the condensed fluid side.

1 is a hollow cylindrical heat transfer tube installed horizontally, 2 is an outer tube installed horizontally, 3 is an annular space formed by the heat transfer tube 1 and the outer tube 2, and 4 is on the inner surface of the heat transfer tube 1. Inner heat transfer fins arranged at predetermined intervals and thermally connected; reference numeral 5 indicates communication holes provided in the inner heat transfer fin 4;
is thermally connected to the outer surface of the heat transfer cylinder 1 and forms an annular space 3.
The outer heat transfer fins 7 are housed in the outer heat transfer fins 6 and are arranged at predetermined intervals. This embodiment shows a case where a gas-liquid two-phase fluid that condenses through heat exchange is caused to flow in the annular space 3.
As shown in FIG. 2, the opening ratio of the flow holes 7 of the outer heat transfer fins 6 is larger on the lower side than on the upper side.
8 and 9 are an inlet and an outlet for condensed fluid, respectively, and 10 and 11 are an inlet and an outlet for a cooling fluid, respectively.

Hereinafter, the operation of the heat exchanger according to the present invention will be explained in the case where it is used as a condenser of a refrigerator using refrigerant as the condensing fluid and water as the cooling fluid.

High-temperature gas refrigerant flows through the inlet 8 and flows through a large number of circulation holes 7 arranged in the outer heat transfer fins 6, while water flows in through the inflow port 10 and flows through the large number of circulation holes arranged in the inner heat transfer fin 4. 5, heat is exchanged using the inner and outer heat transfer fins 4, 6 and the wall surface of the heat transfer tube 1 as heat transfer surfaces, the refrigerant is condensed and liquefied, and the water is heated and becomes hot water from the outlet ports 9, 11, respectively. leak.

At this time, the inner and outer heat transfer fins 4 and 6 are closely attached to the refrigerant and water flow paths, so the heat transfer area is high density and wide. The leading edge effect of a boundary layer that utilizes the thin boundary layer that occurs when passing through the flow holes 5 and 7 in order to cause the heat to flow in a direction approximately perpendicular to the fin surface, and the effect that occurs when passing between the heat transfer fins 4 and 6, respectively. The heat transfer coefficient is greatly improved by the agitation turbulence effect caused by the expansion and contraction of the flow and the collision, making it possible to achieve a smaller size and higher performance heat exchanger.

Furthermore, on the refrigerant side, as it condenses, the amount of condensed liquid that does not contribute to heat transfer increases as it moves from the inlet 8 to the outlet 9, but the opening ratio of the flow holes 7 of the heat transfer fins 6 on the refrigerant side is lower Since we are increasing
The liquid refrigerant condensed on the outer heat transfer fins 6 flows down through the outer heat transfer fins 6 and the heat transfer cylinder 1, passes through the lower flow holes 7 with a large flow area, and heads toward the outlet 9 without falling. Due to the flow, the thin effective heat transfer surface of the liquid film contributing to heat transfer is increased, which can further improve the condensing heat transfer coefficient.

Effects of the Invention As described above, in the condenser of the present invention, a double cylinder consisting of a heat transfer cylinder and an outer cylinder is installed horizontally, and a large number of heat transfer fins with circulation holes are provided on the inner and outer surfaces of the heat transfer cylinder. A flow path for two fluids that exchange heat is formed, one of which passes the condensing fluid, and the condensed fluid side is composed of heat transfer fins with a large opening ratio on the lower side.As a result, a large number of heat transfer fins can be provided. As a result, the heat transfer area can be expanded, and the heat exchanger can be made smaller and more dense.The heat transfer fins with flow holes create a boundary layer leading edge effect and a stirring turbulent flow effect, which increases the heat transfer coefficient. This has greatly improved the size of the heat exchanger, and since the opening ratio of the flow holes in the heat transfer fins on the condensed fluid side is increased toward the bottom, the condensed fluid that flows down can be quickly removed without being left behind. The resulting thin liquid film increases the effective heat transfer area, further improving the condensing heat transfer coefficient and achieving high performance heat exchange.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a condenser showing an embodiment of the present invention, FIG. 2 is a plan view of heat transfer fins on the condensed fluid side of the condenser, and FIGS. 3, 4, and 5 are FIG. 1 is a schematic diagram of a conventional condenser, respectively. DESCRIPTION OF SYMBOLS 1... Heat transfer tube, 2... Outer cylinder, 3... Annular space, 4... Inner heat transfer fin, 5... Communication hole, 6... Outer heat transfer fin, 7... Communication hole.

Claims (1)

[Claims] 1. A double cylinder consisting of a heat transfer cylinder and an outer cylinder is installed horizontally, and a large number of heat transfer fins with circulation holes are provided on the inner and outer surfaces of the heat transfer cylinder to form a flow path for two fluids to exchange heat,
A condenser that allows the condensing fluid to pass through one side, and the condensed fluid side is composed of heat transfer fins with a large opening ratio on the lower side.