JPS62248969A - Defrostation operation control method of 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 Field of the Invention The present invention relates to a heat pump type air conditioner, and more particularly to a defrosting method for melting frost adhering to an outdoor heat exchanger when the outside temperature is low.

2. Description of the Related Art A conventional defrosting operation control method for a heat pump type air conditioner is generally known in which the four-way valve is reversed from the heating operation state and the high temperature, high pressure gas from the compressor is sent to the outdoor heat exchanger.

However, with this method, when the piping length of the refrigeration cycle is extremely long, the suction pressure is operated in a negative pressure range for a long time, resulting in rapid temperature changes in the compressor and a decrease in oil viscosity. However, the reliability of the compressor decreases due to two-phase separation from the refrigeration system, and the temperature of the indoor heat exchanger and piping decreases, so it takes time to restart the heating operation.

An example of a conventional defrosting method will be described with reference to FIG.

FIG. 7 is a refrigeration cycle diagram of a heat pump type air conditioner, showing a compressor 101, a four-way valve 102, a heat exchanger 103 on the non-use side, a check valve 104 that passes during cooling, a capillary tube 105 for cooling, and a use side The heat exchangers 106 are sequentially connected in an annular manner, and the check valve 107 that passes during heating and the heating expansion valve i
In addition to installing the OA series circuit in parallel between the check valve 104 that passes during cooling and the cooling capillary tube 1050, a bypass circuit is also provided in parallel, and a bypass circuit is provided in the bypass circuit that is open only during defrosting. A solenoid valve 109 is provided.

The problem that the invention aims to solve is that even if the capillary tube is bypassed, the amount of circulation within the main body is large, so the piping itself acts as a capillary tube (resistance element), and the negative pressure region in the suction state is basically In addition, even if you try to increase the defrosting ability with an impark type compressor at the highest frequency operation, the negative pressure region will be longer, and in case of multiple refrigerants, a large amount of wet refrigerant will be sucked. There was a downside to coming back.

In view of the problem described in item 1, the present invention aims to deal with the defrosting operation control of a refrigeration cycle with long pipes and multiple refrigerants.

Means to Solve the Problems In order to solve the above problems, the defrosting operation method of JJL's air conditioner uses an inverter compressor, a four-way valve, an indoor heat exchanger, a first throttling device, and an outdoor A refrigeration cycle is constructed by sequentially connecting a heat exchanger and an accumulator in a ring with piping, and a first bypass circuit consisting of a series circuit of a first two-way valve and a check valve is arranged in parallel with the first throttling device. Further, a second bypass 1111 path consisting of a series circuit of a second two-way valve and a second throttle device is provided between the discharge pipe through which high-temperature high-pressure refrigerant always passes and the suction pipe through which low-humidity low-pressure refrigerant always passes, Defrost detection means for detecting the start and end of defrosting operation, and the output of this defrost detection means to control the operation of II) the compression plate compressor valve and the first and second two-way valves. equipped with the means;
Upon receiving the defrosting start signal, the compressor lowers the operating frequency to a low frequency, then switches the four-way valve to enter defrosting operation, and almost simultaneously switches the four-way valve and switches the compressor to the first two-way valve. After opening the second two-way valve, the operating frequency is increased by 1 to the highest frequency to perform defrosting operation.

According to the above-mentioned configuration, the present invention switches between the four-way valve and the first two-way valve and the second two-way valve at the same time when the operating frequency is low or the operating frequency is low, thereby reducing the refrigerant noise at the start time of the defrosting operation. At the same time as the first two-way valve is opened, the low pressure that was throttled by the throttling device is increased by 1, the T circulation amount is increased by 2, and the second two-way valve is opened. As a result, a part of the discharged refrigerant flows into the suction, further increasing the low pressure, reducing the amount of circulation and reducing the temperature drop in the indoor heat exchanger and piping. The dryness of the condensed refrigerant returned to the compressor is reduced to a negative level, preventing liquid banks from entering the compressor, and since the pressure does not become low or negative, the operating frequency can be set to the highest frequency, resulting in high defrosting performance. It is something that can be done. Furthermore, even if the first two-way valve and the second two-way valve are opened before switching the four-way valve, the defrosting performance remains the same. The frost operation control method will be explained with reference to the drawings.

FIG. 1 shows a refrigeration cycle diagram of an air conditioner according to the present invention.

In the figure, an inverter compressor 1, a four-way valve 2, an indoor heat exchanger 3, a first throttling device 4, an outdoor heat exchanger 5, and an accumulation rake 6 are sequentially connected via piping to form a refrigeration cycle. ing.

A first bypass circuit 9 is arranged in parallel with the first throttle device 4 and includes a series circuit of a check valve 7 and a first two-way valve 8.
Furthermore, a second bypass circuit consisting of a series circuit of a second two-way valve 10 and a second throttling device 11 is provided between the discharge pipe 1a through which high-temperature, high-pressure refrigerant always passes, and the suction pipe 1b through which low-humidity, low-pressure refrigerant is always captured. The configuration includes 12. Here, cooling operation is omitted, and the refrigerant flow during heating operation is shown by solid line arrows, and the refrigerant flow during defrosting operation (cooling) ftf rotation cycle is shown by broken line arrows. is a circuit in which the discharged refrigerant passes through the suction pipe 1b and the four-way valve 2 and flows separately to the outdoor heat exchanger 5.

Next, a schematic configuration diagram of the control circuit will be explained with reference to FIG.

The PI figure shows a control circuit using a microcomputer 16, and a signal from a thermistor 15 for detecting and extracting the temperature of the outdoor heat exchanger is inputted to the microcomputer boat 1.

There is an inverter type compressor 1 operated by the impark section 17. Also, send a signal from boat 3 and use four-way valve 2.
The relay coil 20 is energized, the contact 20a is closed, and the four-way valve 2 is turned on. Boat 4 in the same way as above
．． 5.6.7 gives a signal and relay coil 22.2
1.19.18 is energized, contacts 22a, 21a, 1
9a, turn on the IE3a and turn on the outdoor side blower 14, indoor side blower 13, second two-way valve 10, and first two-way valve 8.
I'm letting you do it. Furthermore, 23 is a power supply, 24 is an amplifier, 25
indicates a power switch.

Next, the operation of the air conditioner configured as described above will be explained with reference to FIGS. 2 to 4.

After turning on the power switch 25, the initial setting is the temperature T that determines the start of defrosting of the outdoor piping temperature setting, as shown in Figure 3.
o! , and the temperature Tβ count time n− that determines the end of defrosting.
o, a four-way valve 2, an indoor blower 13, an outdoor blower 14, a first two-way valve 8, a second two-way valve 10, and a compressor 1
The operating frequency is increased by 1 and the stop time setting is set to hl, the frequency at which the impark type compressor 1 is set to low frequency operation upon detecting the start of defrosting is set to fl, and during defrosting operation, the inverter type compressor 1 is set to low frequency operation.
Initialization and initial setting are performed (step) as the highest frequency fmax with the operating frequency of .

After the above-mentioned initialization and initial settings are performed, the first two-way valve 8 and the second two-way valve 10 are closed, and the heating operation is performed. Then, when the outdoor heat exchanger temperature Ta is detected by the outdoor piping sensor 15 and becomes equal to or lower than the set temperature Ti, a signal is sent to the microcomputer 160 input boat 1 to start defrosting (5tsp2).
. Then, a signal is output from the output port 2 (hereinafter referred to as the output port) of the microcomputer 16 to reduce the operating frequency fo of the inverter compressor 1 to the low frequency f1 (
5 step 3).

After that, count for a certain period of time (5top 4).

Then, a signal is output from output port 3 to switch four-way valve 2 (5top5). Furthermore, a signal is output from the output port 4.5 to the indoor fan (hereinafter referred to as the indoor fan) 13.
And the outdoor side blower (hereinafter referred to as outdoor fan) 14 is stopped (stop6.7). As a result, it enters defrosting operation,
Initialize the count time n = o, 5 (5te
p8). Then count a certain amount of time (5t
ep9). When that time has elapsed, a signal is output from the output port 7 to turn the first two-way valve 8 and the second two-way valve 10 into an open state (ON) (step 0.11). Then count time n= again. Initialize ( s t
e p 12). Then, a certain period of time is counted (step 3). Vt, a signal is output from the output port 1, and the inverter drive unit 17 sets the operating frequency fQ of the inverter compressor 1 to the high frequency fmax (step 4). Then, the defrosting operation is continued and the outdoor piping sensor is V-15 detects the outdoor heat exchanger temperature Ta, and if it becomes the same power and high value as the set temperature Tβ, it sends a signal to the input port 1 of the microcomputer 16 to end the defrosting operation (step 5). ). As a result, the microcomputer 16 outputs a signal from the output port 2 to stop the inverter compressor 1 (step 6).

Next, before starting the heating operation, a signal 1δ is sent from the output port 3;, 19). and count time n-. Initialize L (
step 20). Next, count for a certain period of time (st
op21). When that time has elapsed, a signal is output from the output port 2 to operate the impark type compressor 111 and fan blind 3 (steps 23 and 24). Finally, initialize the count time n = o (5tep2
5).

As a result, heating operation is performed.

Furthermore, the state of the refrigerant will be explained with reference to Figure 5, which shows changes in the refrigeration cycle from the operation described above, and Figure 6, which shows a Mollier diagram. The conventional four-way valve switching method is shown by a broken line, and the defrosting method of the present invention is shown by a solid line.

Defrosting takes a long time from T1 to T3. However, in the defrosting method of the present invention, as shown by the solid line, from the start of defrosting T1 to the defrosting operation, some of the discharged gas is in the suction state at the 0 point, so some superheat does not reach Pl. The frequency can be increased to the highest frequency during defrosting. As a result, the input power of the inverter type compressor 1 also increases, and the capacity provided for defrosting also increases. Furthermore, the compressor's own heat is used (discharge (tank-1-) point E → point ○)
Therefore, as shown by T2 in FIG. 5, the defrosting time can also be shortened compared to the conventional method.

With such a defrosting operation control method, defrosting operation can be carried out without any problems with low negative pressure phenomena caused by wide extension of piping and the return phenomenon of condensed refrigerant due to multiple refrigerants.

In this embodiment, the first three-way valve 8 and the second two-way valve 10 are operated after the four-way valve 2 is switched, but it is also possible to operate them at the same time as or before the four-way valve 2 is switched. Even if this is done, the defrosting performance remains the same and is not the main point of the present invention. However, if the switching operation of the first two-way valve 8 and the second two-way valve 10 is not performed before the operating frequency is set to the highest frequency, low negative pressure and return of the condensed refrigerant will occur. Also, the mutual operation timing 13 of the first three-way valve 8 and the second two-way valve 10 is
・−・ The operations may be performed at the same time or with a slight time delay.

Effects of the Invention As is clear from the above embodiments, the present invention starts the defrosting operation by setting the operating frequency to a low frequency and switching the four-way valve after receiving the defrosting operation start signal, and almost simultaneously with this, the first defrosting operation is started. Defrosting cannot be performed by opening the two-way valve and the second two-way valve and increasing the operating frequency to the maximum operating frequency, so even if the piping length of the refrigeration cycle is extended considerably, defrosting will not be possible. The dryness of the condensed refrigerant that has gone and returned to the suction is as dry as possible, and liquid backflow into the compressor can be prevented. Since there is no negative pressure operation at extremely low pressures, the reliability of the compressor is improved, and the temperature drop in the indoor heat exchanger and piping is reduced, making it easier to operate after returning to heating operation.
Can make Yuri faster. Furthermore, since the defrosting operation frequency can be increased to the maximum operating frequency since the low pressure does not become negative pressure reduction, high defrosting ability can be obtained and defrosting can be completed in a short time.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram of an air conditioner according to an embodiment of Mizumoto FI11, Fig. 2 is a schematic configuration diagram of a control circuit that performs defrosting control of the air conditioner, and Fig. 3 is a diagram of the control method. Flow chart diagram, Figure 4 is a time chart diagram of the same control method, Figure 5 is a height change diagram of the conventional method and the method of the present invention, Figure 6 is a Mollier diagram showing a comparison between the conventional method and the method of the present invention, 7
The figure is a refrigeration cycle diagram showing a conventional example. 1... Inverter compressor, 2... Four-way valve, 3... Indoor heat exchanger, 4... First expansion device, 5... ...Outdoor heat exchanger, 6...
... Achimulator, 7... Check valve, 8.
...First two-way valve, 9...First 794
27 circuits, 10...second two-way valve, 11...
...Second aperture device, 12...Second bypass circuit. Name of agent: Patent attorney Toshio Nakao and one other person\N
tsu+kakato haiku〉Mimi hai kyou no 5 P cho I 72 7'3
7i, rLa Fig. 6'1□- Fig. 7/θ3 ab

Claims (1)

[Claims] An inverter compressor, a four-way valve, an indoor heat exchanger, a first throttling device, an outdoor heat exchanger, and an accumulator are sequentially connected in a ring shape with piping to form a refrigeration cycle, and are connected in parallel with the first throttling device. , a first bypass circuit consisting of a series circuit of a check valve and a first two-way valve is provided, and a second bypass circuit is provided between the discharge pipe through which high-temperature, high-pressure refrigerant always passes and the suction pipe through which low-temperature, low-pressure refrigerant always passes. A second bypass circuit consisting of a series circuit of a direct valve and a second throttling device is provided, and further includes a defrost detection means for detecting the start and end of defrosting operation, and an output of the defrost detection means to detect the compressor. , a four-way valve, and means for controlling the operation of each of the first and second two-way valves, and upon receiving a defrosting start signal, reduce the operating frequency of the compressor to a low frequency, and then switch the four-way valves. Then, almost simultaneously with switching the four-way valve, the first two-way valve and the second two-way valve are switched.
A defrosting operation control method for an air conditioner, in which defrosting operation is performed by opening a two-way valve and then increasing the operating frequency to the highest frequency.