JPS63220094A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To elongate a time until spaces between fins are blockaded due to frosting, elevate comfortableness upon room heating and improve energy efficiency, by method wherein a fin between fins having maximum fin width is maximized and the fins are laminated and located so that the fin pitch between fins having the same kind of fin width becomes proportional to the width of the fins. CONSTITUTION:A fin pitch Pf1 between fins 1a having maximum fin width L1 is maximized at the inflow part of air and the fins 1b, 1c, 1d, having the same kinds of fin widths L2, L3, L4, are located in the area of the maximum fin pitch Pf1 so that the fin pitches Pf2, Pf3, Pf4 between the fins 1b, 1c, 1d are reduced gradually in proportion to the widths L2, L3, L4 of respective fins 1b, 1c, 1d, thus, the fins are laminated on a heat transfer tube 2. The layer of frost is formed on the leading edge of the fin 1a, whereat a difference between the absolute humidities of ambient air and saturated wet air is maximum, and heat exchange is effected gradually between cooled and dehumidified air and the fins 1b, 1c, 1d, whereby the layer of frost is formed on the lading edges of respective fins. The fin pitch is increased stepwise, therefore, spaces between fins will never be blockaded even when the layer of frost is formed and thereby the ventilating passages in a heat exchanger may be secured widely.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an outdoor finned heat exchanger such as a heat pump type air conditioner using air as a heat source.

2. Description of the Related Art Conventionally, heat exchangers used in air conditioners, etc.
A finned heat exchanger with a configuration like , Ibl is used. That is, a finned heat exchanger is constructed by arranging a large number of fins 1 in parallel at predetermined intervals to form a fin group, and by intersecting the heat transfer tubes 2 in multiple stages orthogonally to the fin group.

Furthermore, on the surface of the fin 1, in order to improve the heat transfer effect between the gaseous heat exchange fluid such as air and the fin 1,
The fin 1 has a wave shape with a constant wave pitch Pf.

To explain the operation when such a finned heat exchanger is used during heating operation of a heat pump type air conditioner that uses air as a heat source, an outdoor finned heat exchanger functions as an evaporator and absorbs the surrounding air. When the temperature decreases, the evaporation temperature becomes 0° C. or lower, and water vapor in the air adheres to the fin surface as frost 3 to form a frost layer. When the space between the fins 1 is blocked by frost 3, air cannot flow between the fins 1, the heat exchange capacity decreases, and the heating capacity decreases. Frost operation is in progress.

Problems to be Solved by the Invention However, when the finned heat exchanger having the above configuration is used as an outdoor heat exchanger such as a heat pump type air conditioner, the problems shown in FIG. 1 1al as shown in FIG. B-
As shown in the detailed cross-sectional view of the fin air inflow and outflow ends along line B, the turbulence of the main flow occurs from the fin 1 inflow part, so more frost layer 3 is formed at the air inflow part of the fin 1, and the fin 1 is removed in a short time. Since the space between the two was blocked, the amount of air passing through the tube was reduced, and the amount of heat exchanged was significantly reduced in a short period of time.

Therefore, heating operation must be interrupted and defrosting operation must be performed frequently, which impairs the comfort during heating and also has poor energy efficiency.

The present invention eliminates the above-mentioned conventional drawbacks, suppresses the space obstruction of frost between the fins during frost formation, extends the time until the space between the fins is blocked by frost, and provides comfortable heating during heating. The present invention provides an excellent outdoor heat exchanger that improves performance and energy efficiency.

Means for Solving the Problems The finned heat exchanger of the present invention is composed of a group of heat transfer tubes arranged in parallel at predetermined intervals and through which air flows,
A large number of fins of a plurality of types with different fin widths are formed in the direction of the heat transfer tube row, and the fins of the plurality of types of fin widths are arranged such that the fin pitch between the fins of the maximum fin width is adjusted in the air inflow section. fins of the same kind of fin width are positioned so that the fin pitch between the fins is proportional to the fin width at the maximum fin pitch interval.

Effects The present invention, with the above-described configuration, prevents the development of frost on the leading edges of the fins and the fins around the heat transfer tubes, extends the blockage time due to frost clogging between the fins, and reduces the number of defrosting operations. It is possible to improve comfort during heating and improve energy efficiency.

Example An embodiment of the present invention will be described below with reference to FIG. 1(a).

(This will be explained based on bl.

Fig. 1 1al is a fin configuration diagram of the finned heat exchanger of the present invention, and Fig. 1 1al is a detailed cross-sectional view of the air inflow and outflow ends of the fins taken along line AA' in Fig. 1 1al. .

In both figures, la, 1b, lc, and ld are the fin widths L1
, L2, L3, and L4 are different fins, and the fin width L1 is the maximum at the air inlet part.The fin pitch Pfl between the same tenth fin 1a is maximized, and the same fin width is set between the maximum fin pitch Pf1. L2, L
3, L4 fin 1b.

Fin pitch Pf2 between 1c and 1d. Pf3. Pf4
is the fin width L2. of each fin lb, lc, ld. IGL4
The heat exchanger tubes 2 are laminated in such a manner that the heat exchanger tubes 2 are positioned so as to become gradually smaller in proportion to the . That is, at the fin tip of the air inflow section, the apparent fin pitch ptt=Pf2. Pf3
The configuration is such that the fin pitch is several times the original fin pitch PfOO.

Note that the arrow indicates the direction of air inflow.

By adopting the above configuration, in the air inflow section, fins of different lengths in the air inflow direction are connected to the heat exchanger tube 2.
The fins are arranged in stages in the axial direction, and the fin pitch is increased several times. Therefore, a frost layer is formed at the air inflow part of the fin where the absolute humidity difference between the surrounding air, which is related to the amount of frost formation, and the saturated humid air corresponding to the temperature of the heat transfer surface of the heat exchanger is the largest, that is, at the leading edge of the fin 1a. Then, the cooled and dehumidified air gradually exchanges heat with fins lb, then lc, and ld, and a frost layer is formed on the leading edge of each fin. The fin pitch of the fins is gradually increased in the direction of air inflow, so even if the same amount of frost layer is formed as before, the space between the fins will not be blocked, ensuring a wide ventilation path. Can be done. As a result, there is little increase in ventilation resistance, only a slight decrease in the amount of air passing through, and a small decrease in the amount of heat exchange.The number of defrosting operations is reduced, improving comfort during heating, and significantly increasing energy efficiency. It can be improved.

Effects of the Invention As is clear from the above explanation, the heat exchanger with fins of the present invention has a plurality of fins of different fin widths formed in the direction of the row of heat transfer tubes, and a plurality of fins of different fin widths. The various fins are placed in the air inflow section so that the fin pitch between the fins with the maximum fin width is maximized, and within the maximum fin pitch, the fin pitch between the fins with the same fin width is proportional to the fin width. Since it has a laminated structure, the fin pitch of the air inflow portion can be increased. Therefore, it is possible to secure a wide ventilation path during frost formation, reduce the increase in ventilation resistance, reduce the decrease in passing air volume, reduce the performance deterioration of the heat exchanger, reduce the number of defrosting operations, and heat the air. In addition to improving comfort during
It has great effects, such as being able to significantly improve energy efficiency.

[Brief explanation of the drawing]

Fig. 1 fat is a fin plan view of a finned heat exchanger showing one embodiment of the present invention, Fig. 1 (bl is Fig. 1 falO-
Detailed cross-sectional view of the air inflow and outflow ends of the fins taken along line A, FIG. 2(a) is a plan view of the fin shape of a conventional finned heat exchanger, and FIG. FIG. Ia, Ib, 1c, ld...Fin, 2...
...heat exchanger tube, moth, L2. T8. I4...Fin width, PfOlPfl IPf2IPf31Pf4"
”” Name of FinPitch 0 agent Patent attorney Toshio Nakao and 1 other person/(L, /b, IC, ld---Finn Figure 2

Claims (1)

[Claims] It consists of a group of fins arranged in parallel at a predetermined interval, through which air flows, and a group of heat transfer tubes inserted at right angles to the group of fins, through which fluid flows. A large number of fins of different widths are formed, and the plurality of types of fins of different fin widths are arranged so that the fin pitch between the fins with the maximum fin width is maximized at the air inlet part, and the fin pitch between the fins of the maximum fin width is maximized. A heat exchanger with fins having a laminated structure in which fins of the same fin width are positioned so that the fin pitch between them is proportional to the fin width.