JPH0670532B2 - Blower control method for refrigeration system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blower control method for an air-cooled condenser in which a plurality of blowers are arranged, and in particular, controlling the blowers individually or in groups to shut down the operation to a high pressure. The present invention relates to a control method for always keeping the pressure at a substantially constant value.

[Background of the Invention]

A compressor, an air-cooled condenser, a decompressor, and an evaporator are provided to form a refrigeration system, and a plurality of blowers are arranged in the air-cooled condenser, and the operation of the blower is controlled to control high-pressure power. As a method, Sanyo Denki's small refrigerator catalog issued in March 1985 describes that two condenser blowers are arranged in the lateral direction to control the operation of this blower. Since the heat transfer tube of the condenser is horizontally long,
There is a tendency that the amount of refrigerant liquid stored in the lowermost heat transfer tube increases, the heat transfer area decreases, and the cooling performance decreases. Further, in the heat transfer tube portion for supercooling, only a half of the heat exchange tube is subjected to heat exchange, and there is a problem that a stable degree of supercooling cannot be obtained.

[Object of the Invention]

The present invention has been made in view of the above, and an object thereof is to provide a blower control method capable of improving the performance of an air-cooled condenser, stabilizing the condensing pressure, and stably securing a subcooling unit.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention forms an air-cooled condenser in a longitudinal direction, arranges a plurality of fans in the longitudinal direction, the upper end of the heat transfer tube is a refrigerant inlet tube, the lower end is a refrigerant outlet tube, the condensation pressure is When the temperature drops, the blower is preferentially stopped from the blower on the side closer to the refrigerant inlet pipe to control the condensing pressure.

Example of Invention

 An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an air-cooling type condenser, in which a large number of parallel fins 1 penetrate a meandering heat transfer tube 2 to form a heat exchanger 3, and the heat exchanger 3 is formed as shown in the drawing. The entire heat transfer tube 2 has a vertically long shape, and has an upper end formed as a refrigerant gas inlet and a lower end formed as a cooling liquid outlet. In addition, two blowers 4 and 5 are arranged in the heat exchanger 3 in the vertical direction.

Reference numeral 6 is a frame body in which the heat exchanger 3 is arranged on one side and the blowers 4 and 5 are arranged on the other side, and the blowers are connected to the electric motors 7 and 8 mounted on the base 9, respectively. In the figure, the solid arrows indicate the air flow direction, and the dashed arrows indicate the refrigerant flow direction.

The air-cooled condenser is a refrigerant compressor (not shown),
A refrigeration cycle is formed by the pressure reducer and the evaporator.

The high-pressure discharged refrigerant gas discharged from the compressor flows into the air blown by the blowers 4 and 5 while flowing from the upper end inlet of the heat transfer tube 2 of the air-cooled condenser 3 and flowing downward through the heat transfer tube 2. The heat is radiated through the fins 1 and condensed to become a refrigerant liquid which flows out from the lower end outlet and reaches the pressure reducer. The high-pressure refrigerant liquid flows through the decompressor, is decompressed, and then flows into the evaporator. In the evaporator, heat is absorbed from the circulation medium on the other side, the medium is cooled, and the refrigerant itself evaporates to become a refrigerant gas and returns to the compressor.

The above operation is continuously performed, and the cooling operation is performed.

The air-cooled condenser 3 exchanges heat with the intake air blown by the blowers 4 and 5 as described above, and changes from high-pressure superheated steam to saturated steam, and further to saturated liquid and supercooled liquid.

However, when the outside air temperature drops in winter, etc., the blower is stopped by the operation signal of the high pressure switch to prevent the decrease of the refrigeration capacity due to the excessive decrease of the condensation pressure, and the condensation pressure is maintained. Measure The blower first stops the blower 4 on the refrigerant inlet side.

Next, the stop order of the blower will be described.

As a comparative example for explanation, the method of this embodiment in which the priority order of stopping the blower is closest to the refrigerant gas inlet side of the condenser is (I), and conversely, to the liquid outlet side of the condenser. The case where the method of giving priority to the closest one is set to (II) will be compared, and description will be made with reference to FIGS. 4 and 5. The horizontal axis of FIG. 4 is the height distance from the bottom surface of the condenser, and the vertical axis is the heat transfer coefficient of the condenser. The method (II) has a high heat transfer rate at a position where the vertical distance of the condenser is high, but the amount of condensed liquid in the refrigerant pipe is large, so the condensing zone section that is most involved in the condensing performance of the condenser is narrow. .

Moreover, although the section of the supercooling region is wide, since the nearest blower is stopped for heat exchange, the heat passage rate is reduced and the supercooling effect cannot be obtained. On the other hand, in the method (I), the section of the supercooling region is the same as when two fans are operated, and it is possible to effectively exhibit the condensation performance without impairing the heat transfer area of the condenser. Since the blower in the immediate vicinity of the cooling area is operating, a stable supercooling effect can be obtained.

FIG. 5 shows changes in the condensing pressure with respect to the outside air temperature. P ₁ is the operating pressure of the blower control high-pressure switch, and P ₂ is the return pressure. Following the decrease in the outside air temperature, the condensation pressure also decreases as shown by the arrow in the figure. When the condensing pressure reaches P ₁ , the blowers stop, and the condensing pressure rises, but the total number of blowers is not stopped, so the condensing pressure is balanced at a certain point.
If the outside air temperature further decreases at the point (point in the figure), the condensation pressure follows and decreases, leading to the stop of the second-stage blower. When the outside air temperature rises at the point, the condensing pressure rises and eventually reaches the return pressure P ₂ . Condensation pressure is P ₂
When it becomes, the blower that is stopped will start restarting,
Since the balance point of the condensing pressure at this point is the point, the condensing pressure drops to the point, and when the fluctuation of the outside air temperature is large thereafter, the condensing pressure changes by forming the closed loop shown in the figure.

In the above method (II), since the heat exchange performance is poor,
The condensing pressure rises and the balance point moves to. Therefore, the closed loop becomes as shown by the broken line, and the change range of the outside air temperature from the stop of the blower to the operation becomes small.

As described above, the method (I) can slow the change in the condensation pressure with respect to the change in the outside air temperature, as compared with the method (II).
A stable operation of the refrigerator can be performed.

Also, when the blower is switched from full operation to blower control operation, the amount of liquid stored in the condenser is not small, so refrigeration performance is stabilized without hindering the circulation of the refrigerant after the condenser. There is an effect that can be.

〔The invention's effect〕

As described above, according to the present invention, when the blower is stopped, it is possible to reduce the amount of stored refrigerant liquid that is ineffective in heat exchange performance in the condensation. Further, the condensing pressure can be more stabilized against fluctuations in the outside air temperature, and further, there are many effects such that the degree of supercooling can be effectively obtained.

[Brief description of drawings]

1 to 3 show one embodiment of the air-cooled condenser of the present invention. FIG. 1 is a side view, FIG. 2 is a rear view, FIG. 3 is a front view, and FIG. 4 is a heat transfer coefficient. And FIG. 5 is a diagram showing the characteristic of the condensation pressure with respect to the outside air temperature. 1 ... Fin, 2 ... Heat transfer tube, 3 ... Heat exchanger, 4,5 ... Blower, 6 ... Frame, 7,8 ... Electric motor, 9 ... Base.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Amada 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Shimizu Plant, Hitachi, Ltd. (56) References: 53-129757 (JP, U): 47- 34348 (JP, U)

Claims (2)

[Claims] 1. An air-cooling system comprising at least a compressor, a condenser, a pressure reducer, and an evaporator, wherein the condenser has a plurality of juxtaposed fins that penetrate a meandering heat transfer tube and have a plurality of blowers. In a type that is formed by a type condenser and controls the condensing pressure by shutting down the blower, the condenser is formed vertically long, the upper end of the heat transfer pipe is the refrigerant inlet pipe, the lower end is the refrigerant outlet pipe, and the longitudinal direction A method for controlling a blower of a refrigerating apparatus, wherein a plurality of blowers are arranged in the air conditioner, and the blower is preferentially stopped from a blower closer to the refrigerant inlet pipe to control the condensing pressure. 2. A blower control method for a refrigerating apparatus according to claim 1, wherein each of the condenser blowers is connected to an electric motor.