JPH07117272B2 - Operation control device for air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an operation control device for an air conditioner, which prevents dew condensation of a liquid pipe based on a value of a liquid pipe temperature during cooling operation, and particularly to dew condensation. The present invention relates to measures for preventing an excessive decrease in low pressure when returning from the prevention operation to the normal cooling operation.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 54-167541, a compressor whose operating capacity can be adjusted to two stages of full load and unload by an unloader mechanism and an outdoor fan are attached. In an air conditioner in which two indoor units each having an indoor electric expansion valve and an indoor heat exchanger are connected in parallel to an outdoor unit having an outdoor heat exchanger, detection is performed by a room temperature thermostat during cooling operation. Depending on the temperature difference between the room temperature and the set value in the room, the air conditioning state in the room is divided into multiple steps, and the operating capacity of the compressor is adjusted according to which step the air conditioning state in each room is. Therefore, it is a well-known technique to adjust the capacity with respect to the cooling load to exert a predetermined cooling effect.

(Problems to be Solved by the Invention) However, when the operation control of the air conditioner as described above is performed, the following problems occur.

That is, when even a single indoor side demands high capacity, the compressor is loaded at full load, and in the end, in most cases, it will be operated at full load. Therefore, in a region where the outside air temperature is low, the temperature of the liquid pipe is likely to be lowered, and dew condensation is likely to occur on the liquid pipe. Therefore, if the liquid pipe is not protected, water will leak on the ceiling due to dew condensation on the liquid pipe. There is a risk that the user may feel uncomfortable.

Therefore, when the liquid pipe temperature reaches a temperature at which dew condensation occurs during the cooling operation, the liquid pipe temperature is reduced by reducing the refrigerant circulation amount and increasing the high pressure by reducing the operating capacity of the compressor and the air volume of the outdoor fan. It is conceivable to perform dew condensation prevention operation that controls the operating conditions so as to raise the temperature.

However, when returning from the dew condensation prevention operation to the normal cooling operation, there are the following problems.

That is, as shown in FIG. 8, a return command from the condensation prevention operation to the normal cooling operation is output at time t ₀ ((a) in the same figure).
), The operating capacity of the compressor that had been reduced ((b) in the same figure)
(Refer to ()) and the air volume of the outdoor fan (see (c) in the figure) are simultaneously returned to the higher side (in the figure, F / L indicates full load of the compressor, U / L indicates unload), and high pressure Since the pressure drops sharply (see (d) in the same figure), the low pressure also drops sharply (see the circled part in the broken line in (e) in the same figure), and the low pressure becomes a negative pressure, causing seizure of the compressor. There is fear. In that case,
Since the low-pressure pressure switch normally operates to prevent such an accident, the so-called low-pressure cut causes the compressor to stop abnormally.

The present invention has been made in view of such a point, and an object thereof is to provide a compressor by a low pressure cut by providing a means for suppressing a rapid decrease in low pressure when returning from a dew condensation prevention operation to a normal cooling operation. It is to avoid the abnormal stop of.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the present invention, when returning from the dew condensation prevention operation to the normal cooling operation, the operating capacity of the compressor and the air volume of the outdoor fan with a predetermined time difference. To recover.

Specifically, the first solving means is as shown in FIG.
Variable capacity compressor (1), variable air volume outdoor fan (12)
It is premised on an air conditioner equipped with a refrigerant circuit (11) formed by connecting a heat source-side heat exchanger (4), an indoor electric expansion valve (7), and a utilization-side heat exchanger (8).

Then, as an operation control device of the air conditioner, a liquid pipe temperature detecting means (Th4) for detecting the temperature of the liquid pipe of the utilization side heat exchanger (8) and an output of the liquid pipe temperature detecting means (Th4) are provided. In the normal cooling operation, when the liquid pipe temperature becomes lower than the predetermined dew condensation judgment temperature, the operation capacity of the compressor (1) and the air volume of the outdoor fan (12) are forcibly reduced to prevent dew condensation. And a dew condensation prevention control means (51) for controlling the above.

Furthermore, receiving the output of the liquid pipe temperature detection means (Th4),
During the condensation prevention operation by the condensation prevention control means (51),
When the liquid pipe temperature recovers to a predetermined temperature equal to or higher than the condensation determination temperature, a capacity restoring means (52) for controlling the operating capacity of the compressor (1) to return to a high capacity side, and the capacity restoring means (52). When a predetermined time elapses after the operating capacity of the compressor (1) is restored by means of the above, an air flow rate returning means (53) for controlling the air flow rate of the outdoor fan (12) to be returned to a high air flow rate side is provided. .

The second solving means is premised on the air conditioner similar to the first solving means, and is provided with the same liquid pipe temperature detecting means (Th4) and dew condensation preventing control means (51).

Furthermore, receiving the output of the liquid pipe temperature detection means (Th4),
During the condensation prevention operation by the condensation prevention control means (51),
When the liquid pipe temperature recovers to a predetermined temperature equal to or higher than the condensation determination temperature, an air volume returning means (53) for controlling the air volume of the outdoor fan (12) to return to a high air volume side, and the outdoor by the air volume returning means (53) A capacity restoring means (52) is provided for controlling the operation capacity of the compressor (1) to return to a high capacity side when a predetermined time has elapsed after the air volume of the fan (12) has been restored.

The third solving means is configured by the air volume restoring means (53) in the first or second solving means for gradually returning the air volume of the outdoor fan (12).

A fourth solving means is configured by the capacity restoring means (52) in the first, second or third solving means for gradually returning the operating capacity of the compressor (1).

(Operation) With the above configuration, in the invention of claim (1), when the liquid pipe temperature becomes lower than the predetermined dew condensation determination temperature during the cooling operation,
The dew condensation prevention control means (51) controls so that the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are reduced.
The operating conditions are corrected so that the liquid pipe temperature rises.
Then, when the liquid pipe temperature recovers to a predetermined temperature equal to or higher than the dew condensation determination temperature, first, the compressor (1) is operated by the capacity restoring means (52).
The operating capacity of is controlled so as to return to the high capacity side, and when a predetermined time has elapsed thereafter, the air volume restoring means (53)
The air volume of the outdoor fan (12) is controlled so as to return to the high air volume side.

In that case, since the air volume of the outdoor fan (12) initially remains unchanged, only the operating capacity of the compressor (1) increases, so the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are simultaneously subjected to normal cooling operation. A rapid decrease in high pressure due to the return to the hour value is suppressed, and an instantaneous excessive decrease in low pressure is suppressed. Then, after the low pressure is stabilized to some extent, the air volume returning means (53) controls the air volume of the outdoor fan (12) to return to a high air volume, so that the compressor (1) caused by the sudden low pressure drop is reduced. The dew condensation prevention operation returns to the normal cooling operation without causing an abnormal stop.

In the invention of claim (2), when the temperature of the liquid pipe is recovered, first, the air volume of the outdoor fan (12) is controlled to be returned to the high air volume side by the air volume restoring means (53). Although there is an instantaneous drop in high pressure due to an increase in air flow, the operating capacity of the compressor (1) increases after the high pressure stabilizes to some extent, and the operating capacity of the compressor (1) and the outdoor fan (1
There is no sudden drop in low pressure as in the case where the air volume of 2) is restored at the same time, and therefore normal cooling operation is restored without causing abnormal shutdown of the compressor (1) due to low pressure cut.

In the invention of claim (3), the above claim (1) or (2)
In the invention, since the air volume of the outdoor fan (12) is switched stepwise, the operating condition of the normal cooling operation can be restored more quickly without causing a sudden drop in low pressure.

According to the invention of claim (4), in the invention of claim (1), (2) or (3), the compressor () is restored by the capacity restoring means (52) at the time of returning from the dew condensation preventing operation to the normal cooling operation. Since the operating capacity of 1) is controlled so as to increase stepwise, it is possible to quickly return to the normal cooling operation while preventing a sudden drop in low pressure.

(Examples) Examples of the present invention will be described below with reference to FIGS. 2 to 7.

FIG. 2 shows a refrigerant piping system of the air conditioner according to the first embodiment, and a multi-unit in which two indoor units (A) and (B) are connected in parallel to one outdoor unit (X). It is of the type.

In the outdoor unit (X), (1) is a compressor,
(2) is a demister that collects oil in the discharged refrigerant, (3) is a four-way selector valve that switches as shown by the solid line in the drawing during cooling operation, and switches as shown by the broken line in the drawing during heating operation, and (4) shows an outdoor fan An outdoor heat exchanger that is a heat source side heat exchanger that is provided with (12) and functions as a condenser during cooling operation and as an evaporator during heating operation, and (4a) is the outdoor heat exchanger (4).
An auxiliary heat exchanger (5) is an outdoor electric expansion valve that adjusts the refrigerant flow rate during cooling operation and depressurizes the refrigerant during heating operation,
(6) is a receiver for storing the liquid refrigerant, and (9) is an accumulator for removing the liquid refrigerant in the sucked refrigerant.

Further, the indoor units (A) and (B) have the same configuration, and both depressurize the refrigerant during cooling operation,
An indoor electric expansion valve (7) that adjusts the refrigerant flow rate during heating operation, and an indoor fan (13) are attached, and the indoor heat is a usage-side heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation. The exchanger (8) is provided as each main device.

Each of the devices (1) to (9) is connected to the refrigerant pipe (10) so that the refrigerant can flow, and heat (or cold heat) obtained by heat exchange with the outdoor air is moved to remove the indoor air. The main refrigerant circuit (11) is provided so as to be provided.

Here, in the outdoor unit (X), the outdoor fan (12) is composed of two first outdoor fans (12a) and second outdoor fans (12b), and the first outdoor fan (12a).
While the air volume can be switched between a high air volume and a low air volume, the second outdoor fan (12b) is on / off controlled. That is, when the first outdoor fan (12a) has a high air volume and the second outdoor fan (12b) is on, the overall air volume of the outdoor fan (12) becomes a high air volume H (3rd speed), and the first outdoor fan (12a) is When the second outdoor fan (12b) is off at high air volume, the entire outdoor fan (12) has medium air volume M (2nd speed).
In addition, when the first outdoor fan (12a) has a low air volume and the second outdoor fan (12b) is off, the entire outdoor fan (12) has a low air volume L (first speed).

Further, although not shown, the compressor (1) has a scroll mechanism configured to discharge the refrigerant sucked into the high pressure by the relative revolution of two scrolls facing each other, and a scroll mechanism in the middle of a fixed scroll of the scroll mechanism. It incorporates an unloader mechanism that faces a bypass hole that bypasses a part of the discharged refrigerant. Then, a high pressure supply passage (15) for supplying a high pressure from the discharge pipe (10a) to the back pressure side of the unloader piston of the unloader mechanism via the capillary tube (16).
And an unloader passage (17) that connects the middle of the high-pressure supply passage (15) and the suction pipe (10b) via the on-off valve (18), and the on-off valve (18) is closed. Sometimes, high pressure is supplied to the unloader mechanism to make the operating capacity of the compressor (1) 100% full load, while low pressure is supplied to the unloader mechanism to open the compressor (1) when the opening / closing valve (18) is opened. It is designed to unload the operating capacity, which is 50% of the full load.

In addition, the device has many sensors,
(Thd) is arranged in the discharge pipe (10a), a discharge pipe sensor for detecting the discharge pipe temperature, (Ths) is arranged in the suction pipe (10b), a suction pipe sensor for detecting the suction pipe temperature, (Th1) is An outside air temperature sensor, which is arranged at the air intake port of the outdoor heat exchanger (4) and detects the intake air temperature T1 as the outside air temperature, (Th
2) is an outdoor liquid pipe sensor which is arranged on the liquid pipe side of the outdoor heat exchanger (4) and detects the liquid pipe temperature of the outdoor heat exchanger (4),
(Th3) is arranged at the air intake port of the indoor heat exchanger (8), and a room temperature thermometer (Th4) for detecting the intake air temperature Ta as the indoor air temperature is arranged in the liquid pipe of the indoor heat exchanger (8). The indoor liquid pipe sensor which is a liquid pipe temperature detecting means for detecting the liquid pipe temperature Te of the indoor heat exchanger (8), (Th5) is arranged in the gas pipe of the indoor heat exchanger (8), and the indoor heat exchange is performed. Bowl (8)
Indoor gas pipe sensor to detect the temperature of the gas pipe, (Hps) is located in the discharge pipe (10a) and is a high pressure switch for stopping the compressor (1) when the high pressure rises excessively, (Lps) is suction A low-pressure pressure switch arranged in the pipe (10b) for stopping the compressor (1) when the low pressure becomes excessively low, (Ps)
Is placed in the discharge pipe (10a), and before the discharge pressure reaches the excessive rise value at which the high pressure switch (Hps) operates, the open / close valve (18) is opened to unload the compressor (1). A pressure switch for switching the outdoor fan (12) from high air volume to low air volume during heating operation and from low air volume to high air volume during cooling operation. The operation of the air conditioner is controlled by being signal-connected to a controller that controls the operation of the air conditioner.

In the figure, (19) connects the demister (2) and the suction pipe (10b) of the compressor (1) through a capillary (20), and an oil return pipe for returning oil, ( Reference numeral 21) is an injection bypass passage connecting the liquid pipe (10c) and the suction pipe (10b) so that the liquid refrigerant can be bypassed, and the injection bypass passage (21) includes an injection opening / closing valve (22). A capillary tube (23) is provided in order from the liquid pipe (10c) side, and when the cooling operation is started under a low outside air temperature condition or when the low pressure falls excessively, the injection bypass passage (21) is opened to open the liquid refrigerant. By bypassing the suction pipe (10b) to the low pressure switch (L
It is designed to prevent ps) from operating. Further, (24) and (24) are closing valves provided in a communication pipe between the outdoor unit (A) and the room inside.

During the cooling operation of the air conditioner, the refrigerant discharged from the compressor (1) is condensed in the outdoor heat exchanger (4) and is divided into the indoor units (A) and (B) to be distributed to the indoor electric expansion valve (7). ),
After being decompressed in (7) and evaporated in each of the indoor heat exchangers (8), (8), they are combined and circulated so as to return to the compressor (1).
In that case, as shown in FIG. 3, in accordance with the temperature difference ΔT between the room temperature Ta detected by the room temperature thermostat (Th3) and the set temperature Ts in the room, based on the predetermined differential 2ΔT ₀ of the room temperature, the second step air conditioning state is room temperature Ta higher than the [Delta] T _0, the first step and higher than -.DELTA.T ₀ in [Delta] T ₀ or less -
Each indoor unit (A) is divided into three zones consisting of a thermo-off below ΔT (recovering to the upper step with differential 2ΔT ₀ when the room temperature rises).
The operating capacity of the compressor (1) is adjusted according to the air conditioning zone of (B).

Further, as shown in FIG. 4, the outside air temperature sensor (Th
Depending on the range of the value of the outside air temperature T1 detected in 1) with respect to the predetermined first to fourth set temperatures a, b, c, d (a <b <c <d), the outdoor The air volume of the fan (12) is adjusted in three stages. That is, from the higher outside air temperature T1 to the third set temperature c, operation is performed at a high air volume H of the third speed, and after reaching the third set temperature c or less, the second speed is reached until the first set temperature a is reached. The operation is performed at a medium air volume M, and when the temperature becomes equal to or lower than the first set temperature a, the operation is performed at a low air volume L of the first speed while the outside air temperature T1
When the temperature rises and exceeds the second set temperature b, the air volume is restored to medium air volume M, and when the fourth set temperature d is exceeded, the air volume is restored to high air volume H. That is, by controlling the capacity of the compressor (1) and controlling the air volume of the outdoor fan (12), the refrigerant circulation amount is secured and the capacity of the outdoor heat exchanger (4) is adjusted according to the required capacity in each room. Has been done.

The liquid pipe temperature T4 detected by each of the indoor liquid pipe sensors (Th4) is about the first reference value 1 (for example, -4 ° C) which is the freezing determination temperature at which the freezing of the indoor heat exchanger (8) is started. Temperature value), the indoor units (A), (B)
In, the indoor electric expansion valves (7), (7) are fully closed to control only the indoor fan (13) so that the indoor fan (13) is in a thermo-off state. The evaporation temperature in 8) is raised to thaw.

Here, the dew condensation prevention operation and the return operation to the normal cooling operation, which are the features of the present invention, will be described with reference to FIGS. 5 and 6. FIG. 5 is a transition diagram showing changes in the control state in each indoor unit (A), (B), and in the control state, it is in an operating state in which the evaporation temperature Te corresponding to the liquid pipe temperature T4 should be raised. Te up flag TU which is an index indicating
While F is set to “0”, the liquid pipe temperature T4 of the indoor heat exchanger (8) detected by the indoor liquid pipe sensor (Th4) is the second reference temperature n ( For example −
Temperature value of about 2 ° C.), the control state is entered, a timer having a predetermined set time t ₀ (for example, about 5 minutes) is counted while TUF = 0, and liquid When the tube temperature T4 recovers to the second reference temperature n or higher, the above control state is restored, but when the liquid tube temperature T4 does not recover to the second reference temperature n or higher even after the set time t ₀ elapses, the TUF
= 1, that is, the state shifts to the control state in which the Te up command is output.

After that, when the liquid pipe temperature T4 becomes higher than a return temperature m (for example, a temperature value of about 6 ° C.) which is a predetermined value higher than the second reference temperature n, the control state is entered, and TUF = 1 is maintained. When the timer starts counting and the time is up, a timer for delaying only the control signal of the outdoor fan (12) (the compressor (1) in the invention of claim (2)) is set in step S _1. , The control state is restored. It should be noted that when the liquid pipe temperature T4 becomes equal to or lower than the return temperature m before the set time t _{0 of the} timer elapses, the control state is restored.

Here, the control contents of the dew condensation prevention operation and the return operation to the normal cooling operation will be described based on the flowchart of FIG. 6. In step S ₁ , it is determined whether or not the Te up flag TUF is “1”, and the TUF is determined. If = 1, in step S ₂ , the compressor (1) is unloaded, and the outdoor fan (12) is controlled to a low air flow rate “L”. When the determination in step S ₁ becomes TUF = 1, the process proceeds to step S ₃ and it is determined whether or not the timer is counting. If the timer is counting, the compressor (1) is turned off in step S _4. When the timer counts up while the load is returned to the full load, the outdoor fan (12) is returned from the low air volume L to the high air volume H in step S ₅ .

In the above flow, the invention of claim (1), the step S _2, the liquid pipe temperature T4 is lower than the dew determination temperature n, reduces the air volume of the operating capacity and the outdoor fan of the compressor (1) (12) are condensation prevention control means for controlling (51) is arranged to, in step S _4, when the liquid pipe temperature T4 has recovered condensation determination temperature n or more predetermined temperature (return temperature) m,
A capacity restoring means (52) for controlling the operating capacity of the compressor (1) to be returned to the high capacity side is configured. Further, in step S _5, the air volume controls to return the air volume of the outdoor fan (12) when the elapsed the capacitive return means (52) returns after a predetermined time of the operating capacity of the compressor (1) according to the high air volume side Return means (53) is configured.

Therefore, in the invention of claim (1), when the liquid pipe temperature T4 becomes lower than the predetermined dew condensation determination temperature n during the cooling operation of the air conditioner, the dew condensation prevention control means (51) operates the compressor (1). The capacity and the air volume of the outdoor fan (12) are controlled to be reduced, and the operating conditions are corrected so that the liquid pipe temperature T4 rises. After that, when the liquid pipe temperature T4 recovers to a predetermined temperature (reset temperature) m which is equal to or higher than the dew condensation determination temperature n by the dew condensation prevention operation, first, the operating capacity of the compressor (1) is set to the high capacity side (full capacity) by the capacity restoring means (52). The air volume of the outdoor fan (12) is controlled to return to the high air volume side "H" by the air volume recovery means (53) after a lapse of a predetermined time.

Here, when the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are simultaneously returned to the values in the normal cooling operation, the high pressure sharply drops, and thereby the low pressure sharply drops.
Then, the low pressure switch (LPS) may operate to cause a low pressure cut of the compressor (1), but in the present invention, the air volume of the outdoor fan (12) remains the same as the compressor (1).
Since only the operating capacity of is increased, the instantaneous excessive decrease in low pressure is suppressed. Then, after the low pressure is stabilized to a certain extent by the low pressure constant control, the air volume of the outdoor fan (12) is controlled to return to the high air volume "H" by the air volume restoring means (53). It is possible to return from the dew condensation prevention operation to the normal cooling operation while preventing the abnormal stop of (1).

Next, in the invention of claim (2), the capacity restoring means (52) and the air volume restoring means (53) are constituted by the steps in which the steps S ₄ and S ₅ are replaced with each other.

Therefore, in the invention of claim (2), when the liquid pipe temperature T4 is recovered, the outdoor fan (12) is first operated by the air volume restoring means (53).
Since the air volume of the compressor is controlled to return to the high air volume side "H", there is a momentary decrease of the high pressure due to the increase of the air volume of the outdoor fan (12). The operating capacity will increase, and there will be no sudden drop in low pressure, such as when the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are restored at the same time. It is possible to prevent abnormal stoppage of the compressor (1).

Next, the invention of claim (3) will be described. The time chart of FIG. 7 shows the control of the second embodiment according to the invention of claim (3), and when the Te up flag TUF becomes “1” at time t ₁ (see FIG. 7A), the compressor (1) is unloaded (see (b) in the figure), and the air volume of the outdoor fan (12) is "L".
On the other hand, the liquid pipe temperature at time t ₂
When T4 recovers above the return temperature m and becomes TUF = 0 (see (a) in the figure), first, the compressor (1) is returned from unload to full load (see (b) in the figure). The air volume of the outdoor fan (12) is increased from the low air volume L to the medium air volume M (see (c) of the same figure). Then, when the predetermined time T _M has elapsed, the air volume of the outdoor fan (12) is further returned to “H”.

Therefore, in the invention of claim (3), the air volume of the outdoor fan (12) is switched to the medium air volume M at the same time as the return to the normal cooling operation as in the above embodiment, and then the high air volume H is switched to after a lapse of a predetermined time. As described above, since the air volume of the outdoor fan (12) is switched in a stepwise manner, a rapid decrease in low pressure is prevented as in the invention according to claim (1) or (2), while the normal cooling operation is performed more quickly. There is an advantage that the operating conditions can be restored.

Next, although the embodiment is omitted, in the invention of claim (4),
The operating capacity of the compressor (1) shall be adjusted to three or more stages, and when returning from the dew condensation prevention operation to the normal cooling operation, the operating capacity of the compressor (1) is increased by one step from the lowest unload state. After being once increased to the unload state, it is returned to full load when a predetermined time has elapsed. Therefore, similarly to the invention of the above-mentioned claim (3), it is possible to promptly return to the normal cooling operation without causing the abnormal stop of the compressor (1) due to the excessive decrease of the low pressure.

(Effect of the invention) As described above, according to the invention of claim (1), when the liquid pipe temperature becomes equal to or lower than the dew condensation determination temperature during the cooling operation, the operating capacity of the compressor and the air volume of the outdoor fan are reduced. When the liquid pipe temperature recovers to the predetermined temperature above the dew condensation judgment temperature, the operating capacity of the compressor is increased, and after a lapse of a predetermined time, the air volume of the outdoor fan is increased and normal cooling is performed. Since the operation is returned to the normal operation, it is possible to prevent the abnormal stop of the compressor due to the rapid decrease in the low pressure accompanying the return to the normal cooling operation.

According to the invention of claim (2), at the time of returning from the dew condensation preventing operation to the normal cooling operation, the operating capacity of the compressor is increased when a predetermined time has elapsed after increasing the air volume of the outdoor fan. Similar to the invention of the above-mentioned claim (1), it is possible to prevent an abnormal stop of the compressor due to a sudden drop in the low pressure.

According to the invention of claim (3), in the invention of claim (1) or (2), when returning from the dew condensation preventing operation to the normal cooling operation, the air volume of the outdoor fan is increased stepwise. Therefore, it is possible to quickly return to the normal cooling operation while preventing a rapid decrease in low pressure.

According to the invention of claim (4), the above-mentioned claim (1),
In the invention of (2) or (3), since the operation capacity of the compressor is increased stepwise when returning from the dew condensation prevention operation to the normal cooling operation, the same as the invention of claim (4) above. The effect can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 6 show the first embodiment of the present invention, FIG. 2 is a refrigerant piping system diagram showing the overall configuration of the air conditioner, and FIG. 3 is a characteristic diagram showing the switching characteristics of the room temperature thermostat. FIG. 4 is a characteristic diagram showing a switching characteristic of the outdoor fan air volume with respect to the outside air temperature, FIG. 5 is a control state transition diagram showing a transition relationship between normal control and dew condensation prevention control, and FIG. 6 is a flow chart diagram showing control contents. ,
FIGS. 7 (a) to 7 (c) show the second embodiment and are, respectively, time charts showing changes with time in the Te up flag, the operating capacity of the compressor, and the air volume of the outdoor fan. FIGS. 8 (a) to 8 (e) show the Te up flag, the compressor operating capacity, the outdoor fan air volume, and the high and low pressures when the operating capacity of the compressor and the air volume of the outdoor fan are changed at the same time. It is a time chart figure which shows the change with respect to time respectively. 1 …… Compressor 4 …… Outdoor heat exchanger (heat source side heat exchanger) 7 …… Indoor electric expansion valve 8 …… Indoor heat exchanger (use side heat exchanger) 11 …… Main refrigerant circuit 12 …… Outdoor Fan 51 …… Dew condensation prevention control means 52 …… Capacity recovery means 53 …… Air flow rate recovery means Th4 …… Liquid pipe sensor (liquid pipe temperature detection means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Ueno 1304 Kanaoka-machi, Sakai City, Osaka Daikin Industry Co., Ltd., Kanaoka Plant, Sakai Manufacturing Co., Ltd. (56) Reference JP-A-2-133742 (JP, A) 1-136841 (JP, U) Actually opened 51-108250 (JP, U)

Claims (4)

[Claims] 1. A variable capacity compressor (1), a heat source side heat exchanger (4) provided with an outdoor fan (12) having a variable air volume, an indoor electric expansion valve (7), and a use side heat exchanger (8). And a liquid pipe temperature detection means (Th4) for detecting the temperature of the liquid pipe of the utilization side heat exchanger (8), and the liquid pipe temperature. When the liquid pipe temperature becomes lower than the predetermined dew condensation judgment temperature during the normal cooling operation by receiving the output of the detection means (Th4), the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are forced. Condensation prevention control means (51) for controlling to reduce dew condensation prevention operation is provided, and while receiving the output of the liquid pipe temperature detection means (Th4), the condensation prevention operation is being performed by the condensation prevention control means (51). In addition, when the liquid pipe temperature recovers to a predetermined temperature above the condensation judgment temperature, the compressor The operating capacity of 1) the capacity recovery means for controlling so as to return to the high-capacity side (52), the capacitive return means (52)
And an air volume restoring means (53) for controlling the air volume of the outdoor fan (12) to return to a high air volume side when a predetermined time has elapsed after the operating capacity of the compressor (1) was restored by Operation control device for air conditioner. 2. A variable capacity compressor (1), a heat source side heat exchanger (4) provided with an outdoor fan (12) having a variable air volume, an indoor electric expansion valve (7), and a use side heat exchanger (8). And a liquid pipe temperature detection means (Th4) for detecting the temperature of the liquid pipe of the utilization side heat exchanger (8), and the liquid pipe temperature. When the liquid pipe temperature becomes lower than the predetermined dew condensation judgment temperature during the normal cooling operation by receiving the output of the detection means (Th4), the operating capacity of the compressor (1) and the air volume of the outdoor fan (12) are forced. Condensation prevention control means (51) for controlling to reduce dew condensation prevention operation is provided, and while receiving the output of the liquid pipe temperature detection means (Th4), the condensation prevention operation is being performed by the condensation prevention control means (51). In addition, when the temperature of the liquid pipe recovers to a predetermined temperature above the condensation judgment temperature, the outdoor fan (12) An air volume returning means (53) for controlling the air volume to return to the high air volume side, and the compressor (when a predetermined time has elapsed after the air volume of the outdoor fan (12) has been returned by the air volume returning means (53). An operation control device for an air conditioner, comprising: a capacity return means (52) for controlling the operation capacity of 1) to return to a high capacity side. 3. The air flow returning means (53) is an outdoor fan (12).
The operation control device for an air conditioner according to claim 1, wherein the air flow rate of the air conditioner is gradually returned. 4. The capacity restoring means (52) restores the operating capacity of the compressor (1) stepwise, as set forth in claim (1), (2) or (3). Operation control device for air conditioner.