JPS63220092A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To improve the performance of a heat exchanger upon heating at a low temperature as well as comfortable property upon heating and improve energy efficiency, by a method wherein the configuration of fins is made different in the direction of the stages of heat transfer tubes in accordance with the condition of refrigerant, which flows through the heat transfer tube. CONSTITUTION:When a heat exchanger is used as the outdoor heat exchanger of an air- conditioning machine upon room heating operation so that refrigerant enters from the lower stage of heat transfer tubes 2 and flows toward the upper stage of the same tubes 2, a section C, corresponding to the outlet of refrigerant, is constituted of plate fins, whose ventilating resistance is low, while the other part D is constituted of wavy fins, whose ventilating resistance is high. Frost 3, grown on the surfaces of the fins 1 upon heating at a low temperature, is generated from the tip end of fins at the inflow part of air and a time to the blockading of spaces between fins, which is due to frosting, becomes longer than the time in the section D. In the heat exchanger, in which there is no possibility of frosting upon room hating at a low temperature or the like, the configuration of the fins (cut-and-raised fins, for example), whose ventilating resistance is higher and which is provided with better heat transfer efficiency than the fins in the section D, is employed in the section C, whereby much more heat exchange may be effected since the section C is the inlet of the high-temperature refrigerant and the remarkable improvement of energy efficiency may be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a finned heat exchanger for indoor and outdoor use such as an air conditioner that uses air as a heat source.

2. Description of the Related Art Conventionally, heat exchangers used in air conditioners and the like are shown in FIGS. A heat exchanger with fins having a configuration as shown in Fig. 6 is used.That is, a large number of fins 1 are arranged in parallel at predetermined intervals to form a fin group, and the heat exchanger tubes 2 are arranged in multiple stages in this fin group. , are fixed in a perpendicular manner to form a finned heat exchanger.

Furthermore, on the surface of the fin 1, in order to improve the heat transfer effect between the fin 1 and a gaseous heat exchange fluid such as air,
A wave-shaped fin 1 is processed at every pitch P.

In addition, some fins 1 are cut and raised to improve the heat transfer effect.

Problems to be Solved by the Invention To explain the operation when such a finned heat exchanger is used during heating operation of a heat pump type air conditioner using air as a heat source, the outdoor finned heat exchanger has the following problems: It functions as an evaporator, and when the ambient air temperature decreases, the evaporation temperature becomes 0℃ or less, and the water vapor in the air reaches the fin surface.
It adheres as I3 and forms a frost layer. When the space between the fins 1 is blocked by frost 3, air cannot flow between the fins 1 and the heat exchange capacity decreases, reducing the heating capacity. The system had to be interrupted to perform defrosting operation, impairing comfort during heating and not being energy efficient.

In addition, if the cycle is set up so that the refrigerant flows from the upper stage of the heat exchanger tube 2 to the lower stage during cooling operation, during heating operation, the refrigerant flows through the heat exchanger tube 2.
The refrigerant flows from the lower stage to the upper stage while evaporating. Here, as the refrigerant flows from the lower stage to the upper stage, a pressure loss occurs, and the refrigerant temperature decreases as shown in FIG. 7 due to the pressure loss. In other words, in such a chamber heat exchanger, the fins 1 near the heat exchanger tubes 2 at the stepped portion
The temperature is lower than that of the fins 1 in the lower part, and more frost 7 is generated more easily, and the space between the fins 1 is more quickly blocked by frost a, which reduces the heat exchange capacity and accelerates the reduction in heating capacity. It will be done.

Means for Solving the Problems In order to solve the above-mentioned problems, the finned heat exchanger of the present invention differs in the shape of the fins in the direction of the stages of the heat exchanger tubes depending on the state of the refrigerant flowing inside the heat exchanger tubes. It has a shaped configuration.

Effects The present invention, with the above-described configuration, can improve the heat exchanger performance during heating at low temperatures compared to conventional heat exchangers, improve comfort during heating, and improve energy efficiency.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a plan view of the fin shape of the finned heat exchanger of the present invention, and FIGS. 2 and 3 are air inflow and outflow ends of the fin 1 taken along lines A-A' and 8-8' in FIG. A detailed cross-sectional view of the section, with arrows indicating the direction of air flow. In FIG. 1, the fins 1 are fixed perpendicularly to the heat exchanger tubes 2, and the heat exchanger tubes 2 are connected in a meandering manner sequentially from top to bottom as shown in FIG. Here, when the heat exchanger shown in FIG. 4 is used as an outdoor heat exchanger for an air conditioner during heating operation, the refrigerant enters from the lower stage of the heat transfer tube 2 and flows toward the upper stage. If part 0 (Figs. 1 and 4) corresponding to the part is made of plate fins with low ventilation resistance, and the other part (part 0) is made of corrugated fins with high ventilation resistance, the surface of fin 1 during heating at low temperature As shown in Figures 2 and 3, the growing j13 occurs from the fin tip of the air inflow part, and the 0 part has more ventilation resistance, and the frost G blocks between the fins more quickly than the 0 part. do. Part 0 is
Although the fin pitch F is the same as in part 0, ventilation resistance is less due to the difference in fin shape, and the time until the fins are blocked by frost is longer than in part 0.

As is clear from the above explanation, the heat exchanger (
The heat exchanger (Fig. 1) has a longer heating capacity than the conventional heat exchanger (Fig. 5) at low heating temperatures, making it less uncomfortable.

It is possible to reduce the number of defrosting operations, improve comfort during heating, and improve energy efficiency.

In addition, for heat exchangers that do not have to worry about frost formation during low-temperature heating, etc., by adopting a fin shape (for example, cut-up fins) with a higher ventilation resistance and better heat transfer efficiency than the 0 part in Figure 1. During cooling operation, part 0 corresponds to the inlet of high temperature refrigerant, allowing more heat to be exchanged, increasing heat exchange capacity and significantly improving energy efficiency.

Also, in this example, the number of heat transfer tube rows is one row, but
A similar effect can be obtained even if there are multiple rows.

Further, although two types of fin shapes are used, the same effect can be obtained even if multiple types of fins are machined separately in the step direction of the heat exchanger tube depending on the state of the refrigerant flowing inside the heat exchanger tube.

Effects of the Invention As is clear from the above explanation, the finned heat exchanger of the present invention has fins that have different shapes in the direction of the stages of the heat exchanger tubes depending on the state of the refrigerant flowing in the heat exchanger tubes. According to
When used as an outdoor heat exchanger during heating at low temperatures, it improves the sustainability of heating capacity, reduces the number of unpleasant defrosts, improves comfort, and improves energy efficiency.

In addition, if there is no need to worry about frost formation, by changing the fin shape of the part where high-temperature refrigerant flows during cooling to a shape that has more ventilation resistance, heat exchange capacity can be increased and energy efficiency can be significantly improved. , has great effects.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the fin shape of a finned heat exchanger showing an embodiment of the present invention, Fig. 2 is a detailed sectional view taken along line A-A' in Fig. 1, and Fig. 3 is a B 4 is a perspective view of a finned heat exchanger showing an embodiment of the present invention, FIG. 5 is a plan view of the fin shape of a conventional finned heat exchanger, and FIG. 6 is a detailed sectional view taken along line -B'. 5 is a detailed sectional view taken along line EE' in FIG. 5, and FIG. 7 is a refrigerant temperature characteristic diagram of a conventional finned heat exchanger. 1...Fin, 2...Heat transfer tube. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Fin Figure 1 2-Iun Setup Figure 4! Figure 6 Figure 7

Claims (1)

[Claims] A plurality of stages of heat transfer tubes are fixed to a large number of fins arranged at regular intervals in a meandering manner and perpendicular to the fins,
A heat exchanger with fins, wherein the shape of the fins is different in the step direction of the heat exchanger tubes depending on the state of the refrigerant flowing in the heat exchanger tubes.