JPS59219660A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to an air conditioner capable of cooling and/or heating, and more specifically, to detecting the temperature and operating current of an indoor heat exchanger. ": relates to an air conditioner that can control the defrosting operation of an outdoor heat exchanger.

<Prior Art> Generally, a heat pump type air conditioner is configured as shown in FIG. The unit is divided into indoor and outdoor areas.
Reference numeral 1 denotes a compressor for compressing refrigerant, and the refrigerant discharged from the compressor 1 is switched by a four-way valve 2 as shown by the solid line during cooling operation and as shown by the broken line during heating operation. During cooling operation, the air is sent to the indoor heat exchanger 3, cooled and condensed by the air blown by the outdoor blower 6, reduced in pressure by the pressure reducer 4, and then evaporated into the indoor heat exchanger 5, where it performs a cooling action and is sent to the indoor blower 7. Cooling operation is performed by blowing air. During heating operation, the four-way valve 2 is switched as shown by the broken line, and the refrigerant flows in the order of compressor 1 -> indoor heat exchanger 5 -> pressure reducer 4 -> outdoor heat exchanger 3 -> compressor 1, thereby performing heating operation.

Particularly in the case of heating operation in winter, the refrigerant evaporates in the outdoor heat exchanger 3 and condenses in the indoor heat exchanger 5, so the outdoor heat exchanger 3 is cooled and frost forms on its surface. There was a phenomenon in which heat exchange efficiency decreased and heating performance deteriorated.

Conventionally, a defrost control circuit as shown in FIG. 2 has been employed in order to remove so-called so-called so-called adhesion to an outdoor heat exchanger during heating operation. In the figure, 8, 8' are input illumination terminals, I,
6.7 is the same as in FIG. 1, and 9 is an electronic control circuit unit using a microcomputer. This unit 9 has relay outputs 9a to 9d, the relay 10 controls the indoor blower 7, the relay 11 controls the compressor l, the relay 12 controls the outdoor blower 6, and the relay 15 controls the four-way valve ■6 and the timer de-izer 17. Control. Timer diameter sensor 17 has contact +7
a and 17b, a temperature sensing cylinder 18 with a built-in temperature sensor, and a timer motor 19. When the temperature of the temperature sensing cylinder falls below a certain temperature, a cam driven by the timer motor 19 switches the contact point to 17b at regular intervals. Switch.

The thermosensor cylinder detects the temperature of the outdoor heat exchanger 3. Assuming that the temperature of the exchanger 3K is lower than a predetermined temperature during heating operation, the cam switches contact +7b to open the four-way valve 16. is turned off to switch the refrigerant cycle to the box removal cycle, and the relay 13 is operated using the contact 171), and the contact 14 is turned off to stop the outdoor blower 6 and perform defrosting operation.

'', the conventional defrosting method during heating operation measures the temperature of the outdoor heat exchanger 3, assumes that frost has formed when the temperature falls below a predetermined temperature, and uses a timer function. was used to defrost the outdoor heat exchanger. However, since defrosting was performed without detecting the actual heating capacity, frost did not form even at a predetermined temperature or lower as in the case of low temperature and low humidity, and the defrosting operation was started even though there was still sufficient heating capacity. On the other hand, in the case of high humidity, there were various problems such as continued heating operation even though the heating capacity had already been almost exhausted due to frost formation. There were also other problems, such as the large number of outdoor parts such as timer diothers.

<Objective of the Invention> The first object of the present invention is to shift to defrosting operation when the heating capacity decreases by utilizing the correlation between the heating capacity and the indoor heat exchanger temperature and operating current; To provide an air conditioner capable of returning to heating operation when heating capacity is restored.

A second object of the present invention is to provide an air conditioner in which the outdoor (ti11) components are simplified to reduce costs.

<Structure of the Invention> In order to achieve the above object, the air conditioner according to the present invention is a conventional air conditioner in which a compressor, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger are connected. , a temperature sensor that detects the temperature of the indoor heat exchanger or a current detector that detects the operating current of the indoor heat exchanger is installed on or near the indoor heat exchanger, and the temperature detected by the temperature sensor and the current detector is The present invention is characterized in that it is configured by providing a determining means for comparing the amount of change in current over time with a predetermined set value, and the defrosting operation of the outdoor heat exchanger is controlled by the determining means.

<Example> Hereinafter, an air conditioner according to the present invention will be described in detail with reference to the drawings.

FIG. 3 shows a defrosting control circuit according to the present invention corresponding to FIG. 2, and the same numbers as in FIG. 2 do not indicate the same parts. 20
is a temperature sensor, 21 current detector, temperature sensor → No. 2
0 is placed near or above the indoor heat exchanger 5, and the temperature of this indoor heat exchanger 5 is detected, and the current detector 2
1 detects the operating current of the indoor heat exchanger 5, and its temperature and current detection outputs are input to the electronic control circuit unit 9.

When performing defrosting operation, the relay 12.15 is opened by the output terminals 9c and 9d, and the outdoor blower 6 and the four-way valve 16 are stopped. Therefore, during this time, the outdoor heat exchanger 3 is forcibly heated by a heater (not shown) or defrosted by being left alone. FIG. 4 shows a flowchart of the defrosting control according to the present invention. tl is the time from the start of heating and the time from the end of the defrosting operation to the start of the next defrosting judgment, and t2 is the continuous operation time of the compressor 1, which is determined as the time required to shift to steady heating operation after t1 has elapsed. TΔt1 is the temperature detected by the temperature sensor 2° at Δt1 minutes before the above-mentioned t2, and Tt2 is the temperature detected by the temperature sensor 20 at the time point t2 has elapsed, which is the value of ΔT1 times TΔtl−Tt2.

After t1 has elapsed, when the compressor 1 continues to operate continuously for a time t2 during which it can shift to steady heating operation, the outdoor heat exchanger 3
When ΔT1 becomes equal to or higher than a predetermined set value (1) due to a decrease in the heating capacity due to the arrival of the defrosting operation, the defrosting operation is started. That is, the presence or absence of frost formation is determined based on the temporal temperature drop of ΔT1, and it is determined whether or not to start the defrosting operation. Further, at the time of this determination, if ΔT1 is less than the set value f11 even though frosting is progressing due to load fluctuations, the defrosting operation is started when Tt2 becomes less than the predetermined value (2).

Next, the determination of the end of defrosting will be explained. It3 is the detected current at the current detector 21 in the above 3 at the end of defrosting, IΔt2i
d: Current detected by the current detector 21 Δt2 minutes before t3, ΔI2 is the value of IIΔt2−I t8 l. Experiments have shown that the current detected by the current detector 21 is stable immediately after the start of defrosting, but as the frost on the outdoor heat exchanger 3 disappears, the current detected by the current detector 21 increases rapidly. Confirmed. Therefore, even if ΔI2 is less than a predetermined set value (3), the defrosting operation is stopped at LIS t3 and the heating operation is resumed. In addition, if the current detected by the current detector 21 does not increase even though the frost on the outdoor heat exchanger 3 disappears due to the influence of the outdoor wind speed, etc., the defrost will be forced to defrost after 10 minutes of defrosting operation. End the operation and return to heating operation.

It has been confirmed through experiments conducted by the inventors that the temperature change and operating current change over time of the indoor heat exchanger 50 directly reflect the heating capacity, and the above set values f+), +
2+ and f31, the optimum values obtained experimentally are selected.

FIG. 5 shows an example of the controlled temperature one-hour curve of the indoor heat exchanger 5 detected by the temperature sensor 2o, and FIG. 6 shows an example of the controlled temperature curve of the indoor heat exchanger 50 detected by the current detector 21. An example of an hourly operating current curve is shown. The actual defrosting control according to the above-described flowchart 1 can be clearly understood from these characteristic diagrams.

<Effects of the Invention> As described in detail below, according to the present invention, the indoor heat exchanger By directly detecting temperature changes over time with a temperature sensor and changes in operating current with a current detector, the system can shift to defrosting operation when heating capacity decreases.
The most rational defrosting control can be achieved by returning to heating operation once the heating capacity is restored. In addition, it is possible to obtain an air conditioner that is useful for work, such as by eliminating components such as a timer air conditioner on the outdoor side and simplifying the structure.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an air conditioner that is the premise of the present invention, Fig. 2 is a conventional control circuit diagram for detecting the outdoor heat exchanger temperature, and Fig. 3 is a conventional control circuit diagram for detecting the indoor heat exchanger temperature. The control circuit diagram according to the present invention, FIG. 4 is a flowchart for defrosting control, FIG. 5 is a temperature one-hour characteristic curve of the indoor heat exchanger temperature under defrost control, and FIG. 6 is a diagram of the operating current. It is a current one hour characteristic curve diagram. 1... Compressor, 3... Outdoor heat exchanger, 4... Pressure reducer, 5... Indoor heat exchanger, 20... Temperature sensor,
2I and current detector are shown respectively.

Claims (1)

[Claims] 1. In an air conditioner configured by sequentially connecting a compressor 1, an outdoor heat exchanger 3, a pressure reducer 4, and an outdoor heat exchanger 5, the temperature of the indoor heat exchanger 5 or its vicinity is detected. A current detector 21 is attached to the temperature sensor 20 to detect the operating current of the air conditioner, and the amount of change over time in the temperature detected by the temperature sensor 20 and the current detected by the current detector 21 is set to a predetermined set value. An air conditioner characterized in that a determination means for comparison is provided, the start time of the defrosting operation is controlled based on the determination result of the detected temperature by the determination means, and the stop time of the defrosting operation is controlled according to the determination result of the detected current. .