JPH04263793A - Heat exchanger - Google Patents

Abstract

PURPOSE:To uniformize the speed distribution of air which flows between fins and maximize heat exchanging capacity. CONSTITUTION:A heat exchanger is constituted of a group of fins 1, between which air flows, a group of heat transfer tubes 2, through which refrigerant flows, headers 3, 4, connecting the ends of the group of heat transfer tubes 2 and partitioned so as to form a plurality of header chambers 3A, 3B, 4A, 4B, 4C, 4D, and a connecting tube 9, changing the flowing route of refrigerant in the headers 3, 4. The connecting tube 9 is arranged between the header chamber 4C, at the downstream side of the flow direction of the refrigerant upon evaporating, and the header chamber 4A of the most upstream side in the flow direction of the same.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger configured in a multi-pass system using a header in an air conditioner constituting a refrigeration cycle.

0002

BACKGROUND OF THE INVENTION Conventionally, heat exchangers for air conditioners have adopted a multi-pass system using headers in order to suppress pressure loss on the refrigerant side. An example of a conventional heat exchanger will be described below with reference to FIG.

FIG. 2 is a cross-sectional view of a conventional heat exchanger. A large number of heat transfer tubes 22 are inserted between a large number of parallel fins 21, and one end of the group of heat transfer tubes 22 is connected by a header 23, and the other ends are connected by a header 24, respectively. One partition plate 25 is provided at the center inside one header 23, and two partition plates 26, 27 are provided inside the other header 24.
, 26 and 27 regulate the flow direction of the refrigerant.

When the refrigerant evaporates, it flows into the lower part of the other header 24 from the inlet 28 as shown by the solid line arrow, passes through the heat transfer tubes 22 with the flow regulated by the partition plate 27, and flows into the one header 23. flows into the bottom of the The refrigerant that has flown into the lower part of one header 23 passes through the heat transfer tubes 22 again and returns to the middle part of the other header 24, with its flow being regulated by the partition plate 25, and repeats this path sequentially. , and finally flows into the upper part of the other header 24 through the heat transfer tubes 22a and 22b, and flows out from the outlet 29.

[0005]

However, with the conventional heat exchanger described above, it is difficult to equalize the flow rate of the refrigerant in the heat exchanger tubes 22a and 22b. In other words, the gas-liquid two-phase refrigerant flowing inside each heat transfer tube 22 flows through the fins 21
It exchanges heat with the air flowing between it and evaporates, becoming a gas refrigerant. However, due to the occurrence of drift in the refrigerant in the heat transfer tubes 22a and 22b on the final outlet side, a large amount of liquid component flows to one side and a small amount flows to the other side.

[0006] In the heat transfer tubes 22a and 22b, in which the liquid component is small, the refrigerant completely evaporates in the middle of the heat transfer tube, and thereafter only the single-phase flow of gas refrigerant performs sensible heat exchange. Therefore, the temperature inside the heat exchanger tube increases and gradually reaches or exceeds the dew point temperature of the incoming air, making it difficult for dew condensation to form on the surfaces of the fins 21. Therefore, fresh air tends to flow between the fins 21 where no dew condensation occurs, rather than between the fins 21 where dew condensation occurs and the ventilation resistance is large, resulting in non-uniform wind speed distribution.

As a result, a large amount of air flows into areas where the refrigerant with a small liquid component flows, that is, where the heat exchange capacity is small, and it becomes difficult for air to flow into areas with a large amount of liquid components, which normally contribute to heat transfer, resulting in heat transfer. The issue was that exchange capacity was reduced.

[0008] An object of the present invention is to provide a heat exchanger in which the velocity distribution of the air flowing between the fins is made uniform and the heat exchange ability is maximized.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a group of fins into which air flows, a group of heat transfer tubes inserted into the group of fins and through which a refrigerant flows, and a group of heat transfer tubes through which a refrigerant flows. A header that connects the ends of the header and defines a plurality of header chambers, and a connecting pipe that changes the flow path of the refrigerant in the header. On the other hand, it is a heat exchanger disposed between the downstream header chamber and the most upstream header chamber.

0010

[Operation] According to the present invention, a connecting pipe is provided between the downstream header chamber and the most upstream header chamber to change the flow path of the refrigerant, and when the liquid component in the refrigerant is large, the most upstream header By flowing the refrigerant into the chamber, the refrigerant flowing inside the uppermost heat transfer tube becomes a gas-liquid two-phase refrigerant. As a result, the uppermost fin group is lowered to below the dew point temperature of the air, causing dew to condense, making the wind speed distribution of the incoming air uniform, and making it possible to maximize the heat exchange capacity of the heat exchanger. It is something.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a sectional view of the heat exchanger of the present invention.

In FIG. 1, a large number of heat transfer tubes 2 are inserted between a large number of parallel fins 1. A header 3 on the return side that connects one end of the two groups of heat exchanger tubes and a header 4 on the inflow/outlet side that connects the other end are provided, and these headers 3 and 4 are integral in the vertical direction, and It is a straight pipe.

A partition plate 5 is provided in the center of the header 3 on the return side, and the partition plate 5 divides the inside of the header 3 on the return side into an upper header chamber 3A and a lower header chamber 3B. are doing. Furthermore, three partition plates 6, 7, 8 are provided inside the header 4 on the inflow/outlet side, and these partition plates 6, 7, 8 divide the inside of the header 4 on the inflow/outlet side into the uppermost header chamber 4A and the uppermost header chamber 4A. It is divided into a header chamber 4B, a lower header chamber 4C, and a lowermost header chamber 4D. These partition plates 5, 6, 7, and 8 regulate the flow direction of the refrigerant.

A connecting pipe 9 is provided between the uppermost header chamber 4A and the lower header chamber 4C to change the flow path of the refrigerant. Further, an inlet 10 is formed in the lowermost header chamber 4D, and an outlet 11 is formed in the upper header chamber 4B.

In the above configuration, during evaporation, the gas-liquid two-phase refrigerant flows into the lowermost header chamber 4D of the header 4 through the inlet 10, as shown by the solid arrow in FIG.
The flow direction is regulated by the heat exchanger tubes 2, so that it flows into the lower header chamber 3B of the header 3 on the return side, and then the flow direction is regulated by the partition plate 5, and it flows through the heat exchanger tubes 2 again to the inlet and outlet side. Return to the lower header chamber 4C of the header 4.

The flow direction of the refrigerant returned to the lower header chamber 4C of the header 4 on the inflow/outlet side is regulated by both partition plates 7, 8, and passes through the connecting pipe 9 to the header 4 on the inflow/outlet side.
It flows into the uppermost header chamber 4A of the header 3 on the return side through the heat exchanger tubes 2, where the flow direction is regulated by the partition plate 6, and then flows into the upper header chamber 3A of the header 3 on the return side, and the flow direction is regulated by the partition plate 5. The heat exchanger passes through the heat transfer tube 2 and returns to the upper header chamber 4B of the header 4 on the inlet and outlet side. The refrigerant that has returned to the upper header chamber 4B exits the heat exchanger through the outlet 11.

While flowing in this manner, the gas-liquid two-phase refrigerant exchanges heat with the air through the fins 1 and the like, and exits the heat exchanger completely in a gas state. The refrigerant in this system is a gas-liquid two-phase flow with mostly liquid components.

As mentioned above, the refrigerant that has returned from the lower header chamber 3B of the header 3 on the return side through the heat transfer tubes 2 to the lower header chamber 4C of the header 4 on the inflow/outlet side and then entered the connecting pipe 9 is , because only half of the heat exchanger is still exchanging heat, only half of the liquid component in the refrigerant has evaporated.

Therefore, the refrigerant in the heat exchanger tubes 2a and 2b, which are provided from the top header chamber 4A to the top header chamber 3A and located at the top of the heat exchanger, has a sufficiently large liquid component and is transferred to the air through the fins 1. Even if it evaporates by exchanging heat with the gas, it will not completely gasify, and the gas-liquid two-phase state will be maintained. Therefore, the temperature of the fin 1 in the portion where the heat exchanger tubes 2a, 2b are inserted is below the dew point temperature of the incoming air, and the fin 1
Condensation occurs, and the ventilation resistance of the incoming air becomes uniform. As a result, the wind speed distribution also becomes uniform.

Furthermore, since the condensed water falls from the top to the bottom of the fins 1 due to gravity, the entire heat exchanger is evenly covered with condensed water, and the air velocity distribution throughout the heat exchanger becomes uniform, which improves heat exchange. This makes it possible to maximize the heat exchange capacity of the vessel.

In the embodiment of the present invention described above, the connecting pipe 9 is arranged in the header 4 on the inlet and outlet side, but the connecting pipe 9 is arranged in the header 3 on the return side depending on the number of passes based on the number of header chambers. It is also possible to set

[0022]

As described above, according to the present invention, by providing the header with a connecting pipe that changes the flow path of the refrigerant, the refrigerant with a large liquid component can flow into the upper part of the heat exchanger, and the fin It is possible to make the entire air condensate and to make the wind speed distribution of the inflowing air uniform, making it possible to maximize the heat exchange ability of the heat exchanger.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a heat exchanger showing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional heat exchanger.

[Explanation of symbols]

1 Fin 2 Heat exchanger tubes 2a, 2b Top heat exchanger tube 3 Return side header 3A
Upper header chamber 3B Lower header chamber 4 Inflow/outlet side header 4A
Top header chamber 4B Top header chamber 4C Bottom header chamber 4D Bottom header chamber 5 Partition plates 6, 7, 8 Partition plate 9 Connecting pipe 10 Inlet 11 Outlet

Claims (1)

[Claims] 1. A group of fins into which air flows, a group of heat transfer tubes inserted into the group of fins and through which a refrigerant flows, and ends of the group of heat transfer tubes are connected and a plurality of header chambers are defined. the header, and a connecting pipe that changes the flow path of the refrigerant in the header, and the connecting pipe is
A heat exchanger characterized in that it is disposed between a downstream header chamber and an upstream header chamber with respect to the flow direction of refrigerant during evaporation.