JPH0827080B2 - Operation control device for air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for an air conditioner, and more particularly to measures for preventing dew condensation of an indoor heat exchanger during cooling operation.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 1-169751, an air conditioner including a refrigerant circuit in which a compressor, an outdoor heat exchanger, a pressure reducing valve, and an indoor heat exchanger are sequentially connected. In the system, if dew condensation occurs on the indoor heat exchanger, the amount of heat exchange with the refrigerant is increased by increasing the air volume of the blower fan to prevent condensation or a variable capacity compressor. A well-known technique is provided to prevent dew condensation by reducing the capacity of the compressor when dew condensation occurs, and to prevent dew condensation by heating the dew condensation prevention heater when dew condensation occurs. Is.

(Problems to be Solved by the Invention) However, in the case where the air volume of the blower fan is increased like the above-mentioned conventional one, it is necessary to increase the capacity to a large capacity so that the fan is not always used, which causes an increase in cost. Invite. Further, providing a variable-capacity compressor or a dew-prevention heater in order to prevent dew condensation eventually leads to an increase in cost.

On the other hand, it may be possible to improve the heat insulating property of the indoor heat exchanger, but there is a problem in that it imposes design restrictions.

The present invention has been made in view of such a point, and an object thereof is to ensure high refrigerating efficiency by controlling the discharge refrigerant temperature to an optimum value, and under conditions where dew condensation easily occurs, By taking measures to control the state of (1) to reduce the cooling capacity of the indoor heat exchanger, it is intended to prevent dew condensation without increasing cost and restricting design.

(Means for Solving the Problems) In order to achieve the above object, the first solving means of the present invention is
As shown in FIG. 1A, a compressor (1), an outdoor heat exchanger (3), an electric expansion valve (5) and an indoor heat exchanger (6) were connected in sequence to a refrigerant circuit (9). It is premised on an air conditioner.

Then, as an operation control device of the air conditioner, an evaporation temperature detecting means (The) for detecting the evaporation temperature of the refrigerant in the indoor heat exchanger (6) during the cooling operation, and during the cooling operation,
The condensation temperature detecting means (Thc) for detecting the condensation temperature of the refrigerant in the outdoor heat exchanger (3) and the outputs of the evaporation temperature detecting means (The) and the condensation temperature detecting means (Thc) are received,
A calculating means (51) for calculating an optimum temperature of the discharge refrigerant temperature that gives an optimum refrigerating effect as a function of the evaporation temperature and the condensation temperature of the refrigerant at that time, and a discharge temperature detecting means (Th2) for detecting the discharge refrigerant temperature. An opening for controlling the opening of the electric expansion valve (5), which receives the output of the discharge temperature detecting means (Th2) and uses the optimum temperature calculated by the calculating means (51) as a control target value of the discharge refrigerant temperature. A control means (52) is provided. Further, the control target value of the discharged refrigerant in the opening control of the opening control means (52) is set by an external input so as to be changed to a value higher than the optimum temperature calculated by the calculation means (51) by a constant value. The configuration is such that setting means (Swa) is provided.

As shown in FIG. 1B, the second solution means is, in addition to the operation control device of the air conditioner of the first solution means, humidity detection for detecting the humidity of the intake air of the indoor heat exchanger (6). Means (Hu) shall be provided.

Then, in place of the setting means (Swa) in the first solving means, when the humidity of the intake air reaches a predetermined value or more when the output of the humidity detecting means (Hu) is received, the opening control means (5
The control means of the discharged refrigerant in the opening degree control of 2) is provided with a changing means (53) for changing the control target value to a value higher than the optimum temperature calculated by the calculating means (51) by a constant value.

(Operation) With the above configuration, in the invention of claim (1), during the cooling operation of the air conditioner, the evaporation temperature and the condensation temperature of the refrigerant detected by the evaporation temperature detection means (The) by the calculation means (51). The optimum temperature of the discharge refrigerant temperature that gives the optimum refrigerating effect is calculated according to the condensation temperature of the refrigerant detected by the detection means (Thc), and the opening temperature control means (52) causes the discharge temperature detection means (Th2). The opening degree of the electric expansion valve (5) is controlled so that the discharged refrigerant temperature detected in (3) converges to the optimum temperature, and the refrigerant state is maintained at an appropriate value.

In that case, depending on the indoor environment, the indoor heat exchanger (6)
May dislike the dew. On the other hand, since the discharge refrigerant temperature that gives the optimum refrigerating effect, that is, the state of the suction refrigerant that gives the optimum temperature is somewhat moist, dew may occur in the indoor heat exchanger (6) on the suction line side. . Here, in the invention of claim (1), the setting means (Sw
According to (a), when the control target value of the discharge refrigerant is changed to a value higher than the optimum temperature by a certain value according to the external input, the intake refrigerant temperature that matches the control target value of the discharge refrigerant temperature also increases, and accordingly The opening of the electric expansion valve (5) is reduced,
The superheat of the suction refrigerant is controlled to be high. That is, the refrigerant state on the outlet side of the indoor heat exchanger (6) is maintained on the dry side, the capacity of the indoor heat exchanger (6) is reduced, and dew condensation is prevented. Therefore, it is possible to prevent the dew condensation according to the user's request, without causing a restriction in design and an increase in cost.

In the invention of claim (2), instead of the setting means (Swa) in the invention of claim (1), the humidity of the suction air detected by the humidity detecting means (Hu) is set to a predetermined value by the changing means (53). When it becomes higher than the above value, the control target value of the discharge refrigerant temperature is changed to a value higher than the optimum temperature by a certain value, so that the indoor heat exchanger (6) is always kept at a high capacity and dew is likely to occur. Under the conditions, the indoor heat exchanger (6) automatically
The cooling capacity of the above is reduced, and dew is prevented.

(Example) Hereinafter, the Example of this invention is described based on drawing.

First, the first embodiment will be described. FIG. 2 shows a refrigerant piping system of the air conditioner according to the second embodiment, (1)
Is a compressor, and (2) is a solid line in the figure during cooling operation.
A four-way switching valve that switches as shown by the broken line in the figure during heating operation,
(3) is an outdoor heat exchanger that is a heat source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation, (4) is a receiver for storing liquid refrigerant, (5)
Is an electric expansion valve having a refrigerant pressure reducing function and a refrigerant flow rate adjusting function, and (6) is an indoor side heat exchanger that is installed indoors and functions as an evaporator during cooling operation and as a condenser during heating operation. The heat exchanger (7) is an accumulator which is provided in the suction pipe of the compressor (1) and removes the liquid refrigerant in the suction refrigerant.

The above-mentioned devices (1) to (7) are sequentially connected by a refrigerant pipe (8), and a refrigerant circuit (9) configured to cause heat transfer by circulation of the refrigerant is configured.

Here, an oil recovery device (10) for recovering oil in the discharged refrigerant is provided on the discharge side of the compressor (1) of the refrigerant circuit (9), and the oil recovery device (10) is provided. From compressor (1)-
Oil collector (10) up to the suction pipe between the accumulator (7)
An oil return passage (11) is provided for returning the oil of (1) to the suction side of the compressor (1). And this oil return passage (1
In 1), an opening / closing valve (12) for opening and closing a passage is provided, and the opening / closing valve (12) is normally closed, while a predetermined control is performed when the compressor (1) is started. Opened by
Part of the oil and the discharged refrigerant of the oil recovery device (10) is returned to the suction side of the compressor (1).

In the liquid pipe of the refrigerant circuit (9), the receiver (4) and the electric expansion valve (5) have a common path (so that the electric expansion valve (5) communicates with the lower part of the receiver (4), that is, the liquid part. 8a) is arranged in series, and the point (P), which is the end of the common path (8a) on the upper side of the receiver (4), and the outdoor heat exchanger (3) are connected to the receiver (4) side. First inflow passage (8b) through the first check valve (21) that allows only the circulation of the refrigerant of
Therefore, between the point (P) of the common path (8a) and the indoor heat exchanger (6), a second check valve (22) that allows only the refrigerant to flow to the receiver (4) side is provided. Point (Q), which is the end of the common path (8a) on the side of the electric expansion valve (5) and is connected to the second inflow path (8c), respectively, and the first check valve (21) -outdoor The point (S) between the heat exchangers (3) is the first
A point between the point (Q) on the common channel (8a) and the second check valve (22) -indoor heat exchanger (6) by the first outflow channel (8d) via the capillary tube (C ₁ ). (R) is connected by the second outflow passage (8e) via the second capillary tube (C ₂ ).

That is, during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) is stored in the receiver (4) through the first check valve (21), and the electric expansion valve (5) and the second capillary tube are stored. After decompressing with (C ₂ ), indoor heat exchanger (6)
In the heating operation, the liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) passes through the second check valve (22) to the receiver (4). Is stored,
After the pressure is reduced by the electric expansion valve (5) and the first capillary tube (C ₁ ), it is evaporated in the outdoor heat exchanger (3) and returned to the compressor (1).

In addition, (8f) is a liquid seal prevention bypass passage provided by bypassing the first check valve (21) in the first inflow passage (8b) between the point (P) and the point (S), A third capillary tube (C ₃ ) for depressurizing the refrigerant is provided in the liquid seal prevention bypass passage (8f).

Further, sensors are arranged in the air conditioner, (Th2) is arranged in the discharge pipe of the compressor (1), and a discharge pipe sensor as a discharge temperature detecting unit for detecting the discharge pipe temperature T ₂ , (Thc) is arranged in the liquid pipe of the outdoor heat exchanger (3) and is an external heat exchange sensor as a condensing temperature detecting means for detecting the condensing temperature Tc of the refrigerant during the cooling operation, and (Tha) is the outdoor heat exchanger (3). ) Is installed in the air intake port and detects the outside air temperature, and (The) is installed in the liquid pipe of the indoor heat exchanger (6) and serves as evaporation temperature detecting means for detecting the evaporation temperature Te during the refrigerant operation. The indoor heat exchange sensor, (Thr) is an indoor suction sensor which is arranged at the air suction port of the indoor heat exchanger (6) and detects the suction air temperature Tr, and each of the above sensors operates the air conditioner. It is connected to a controller (not shown) for controlling the input of signals. , By the controller, it is adapted to control the operation of each device in response to the signal of the sensor.

Next, the control contents of the controller will be described with reference to FIGS. 3 and 4.

FIG. 3 shows the contents of the EER control for maintaining the refrigeration effect EER at the maximum during the cooling operation. In step S ₁ , the evaporation temperature Te and the external heat exchange sensor detected by the inner heat exchange sensor (The) are shown. the discharge pipe temperature T ₂ detected respectively input at the condensation temperature Tc and the discharge pipe sensor is detected by (Thc) (Th2), in step S _2, the following equation (1) Tk = 4-1.13Te + 1.72Tc ( Based on 1), calculate the optimum temperature Tk, which is the discharge pipe temperature that gives the optimum refrigeration effect EER.

Next, in step S ₃ , the temperature difference ΔT ₂ between the discharge pipe temperature T ₂ and the optimum temperature Tk is calculated based on the formula ΔT ₂ = T ₂ −Tk, and then in step S ₄ , | ΔT ₂ | ≦ 5? Whether or not, that is, whether or not the discharge pipe temperature T ₂ has converged within a certain range above and below the optimum temperature Tk, until it converges, the process proceeds to step S _5, and whether ΔT ₂ is positive, that is, the discharge It is determined whether the pipe temperature T ₂ is higher than the optimum temperature Tk, and if the discharge pipe temperature T ₂ is higher, step S
_6, while controlling to open the motor-operated expansion valve (5) to moderate, the lower the better of the discharge pipe temperature T _2, at step S _7, to close moderately opening degree of the electronic expansion valve (5) To control.
That is, the opening degree of the electric expansion valve (5) is controlled with the optimum temperature Tk as the control target value of the discharge pipe temperature T ₂ .

On the other hand, when it is determined in step S ₄ that | ΔT ₂ | ≦ 5 and the discharge pipe temperature T ₂ converges within a certain range above and below the optimum temperature Tk, the process proceeds to step S ₈ and the following fuzzy control is executed. To do.

That is, as shown in FIG. 4, in step R ₁ , P-
After updating the opening drive pulse P of the electric expansion valve (5) with 1 = P (P-1 is the previous drive pulse), the discharge pipe sensor abnormality becomes “1” at the time of abnormality in step R _2. flag
It is determined whether Ft2 is "1". If the discharge pipe sensor (Th2) is not abnormal and the connection of the dew-prevention changeover switch (Swa) that is switched by the user from outside is on the terminal "0" side where the dew-prevention operation is not performed, step R ₃ Proceed to step 2 and determine whether the temperature difference ΔTr between the intake air temperature Tr and the set temperature Trs detected by the indoor suction sensor (Thr) (however, ΔTr = Tr-Trs during cooling operation) is 2.5deg or more. Then, if ΔTr ≧ 2.5, the routine proceeds to step R ₄ , where the drive pulse P for the opening degree of the electric expansion valve (5) is calculated based on the following equation (2) P = 3.2ΔT ₂ (2), If ΔTr ≧ 2.5, that is, intake air temperature T
When r is converged within the upper and lower predetermined range of the set temperature Trs, the procedure proceeds to step R _5, the following equation (3) _{P = 3.2ΔT 2 + 6.4ΔTr (3} ) the basis electric expansion valve (5) opening drive of The pulse P is calculated. That is, in the above formula (3), the temperature difference ΔT ₂ between the discharge pipe temperature T ₂ and the optimum temperature Tk, and the intake air temperature Tr−the set temperature Trs.
The opening degree of the electric expansion valve (5) is controlled on the basis of a value obtained by weighting the differential temperature ΔTr of 1 to 2 with.

On the other hand, when the connection of prevention with dew selector switch (Swa) is switched to the terminal "1" side to perform prevention control with dew, the process proceeds to step R _6, the opening P of the electric expansion valve (5)
Is calculated based on the following equation (4) P = 3.2 (ΔT ₂ −5) (4). That is, the dew condensation prevention control is performed so that the control target value of the discharge pipe temperature T ₂ is switched to a value higher than the optimum temperature Tk by a constant value (5 deg). As shown in the Mollier diagram of FIG. 5, this is because the state of the suction refrigerant and the discharge refrigerant is shifted from the state corresponding to the optimum temperature Tk (the state indicated by the solid line) to the state indicated by the broken line on the right side, and The state is changed from the gas-liquid boundary line to the inside of the gas phase side, that is, the state is dried.

In the judgment at the step R _2, the discharge pipe sensor (Th
If 2) is abnormal, the process moves to step R ₅ .

Next, when the control of the above step R ₄ , R ₅ or R ₆ is completed, the routine proceeds to step R ₇ , where it is determined whether or not | P | ≦ 5. When the commanded drive pulse P is small, the control state It is judged that there is little need to change the value, and the process returns to the main flow, while if | P | ≦ 5, proceed to step R ₈ and
It is determined whether P> 0. Then, if P> 0 and the command is to increase the opening degree of the electric expansion valve (5), step R ₁₁
In, P-1 ≦ P whether that is the current drive pulse P it is determined whether or not greater than the previous drive pulse P-1, the larger the better this time, in step R _12, the drive command value P As described above, the opening degree of the electric expansion valve (5) is opened, and if the drive command value P of this time is equal to or less than the drive command value P-1 of the previous time, the process directly returns to the main flow.

In the judgment at the step R _8, when not P> 0, the process proceeds to step R _9, last from the drive command P-1 of this drive command P is small that is, if the electric expansion valve (5)
If the opening change amount of is larger this time, step R
_{At 10} , the opening of the electric expansion valve (5) is controlled to be closed according to the drive command P, and when the amount of change by the current drive command P is less than or equal to the previous time, the opening of the electric expansion valve (5) is changed. Return to the main flow without performing.

In the above flow, the control of step S ₂ constitutes the optimum temperature calculation means (51) for calculating the optimum temperature Tk of the discharge pipe temperature that gives the optimum refrigeration effect as a function of the evaporation temperature Te and the condensation temperature Tc of the refrigerant. Under the control of step R ₈ to R _12, opens the discharge refrigerant temperature T ₂ controls the degree of opening of the electric expansion valve (5) to converge to the optimum temperature Tk is calculated at the optimum temperature calculating means (51) A degree control means (52).

Further, the dew condensation prevention changeover switch (Swa) changes the control target value of the discharge refrigerant temperature in the opening degree control to a value higher than the optimum temperature Tk calculated by the optimum temperature calculation means (51) by a constant value. Thus, it has a function as a setting means for setting by external input.

Therefore, in the above-described embodiment, during the operation of the air conditioner, the evaporation temperature T of the refrigerant detected by the internal heat exchange sensor (evaporation temperature detection means) (The) by the optimum temperature calculation means (51).
The discharge refrigerant temperature T ₂ that gives the optimum refrigerating effect EER is calculated based on the above equation (1) according to e and the refrigerant condensing temperature Tc detected by the external heat exchange sensor (condensing temperature detecting means) (Thc). To be done.

That is, as shown in the Mollier diagram of FIG. 5, the high-pressure side pressure is Hp, the low-pressure side pressure is Lp, the inlet temperature of the gas refrigerant in the compressor (1) is T ₁ , and the outlet temperature is T ₂ (that is, Assuming that the discharge pipe temperature is T ₂ ), in polytropic compression, the following equation (5) T ₂ = T ₁ (Hp / Lp) ^{n-1 / n} (5) (where n is the polytropic index and the compressor ( 1)
Is determined by the type, volume, etc.), but the pressure value on the high-pressure side
Hp can be replaced by the condensation temperature Tc, and the low-pressure side pressure value Lp can be replaced by the evaporation temperature Te. Also, it is determined that the superheat degree Sh is about 2 ° C, which gives a moist refrigerant state (see Fig. 5). Thus, T ₁ is determined from the relationship between T ₂ and T _1, and in the end, it is expressed by the following equation (6) T ₂ = αTe + βTc + γ (6). Then, in the present embodiment, the optimum temperature Tk of the discharge pipe temperature T ₂ that gives the optimum refrigeration effect EER is expressed by the above formula (1) by experiments.

Therefore, the opening control means (52) controls the discharge pipe temperature.
Since the opening degree of the electric expansion valve (5) is controlled so that T ₂ converges to the optimum temperature Tk, even if the operating capacity of the compressor (1) is fixed, the refrigerant state in the refrigerant circuit (9) is appropriate. It will be controlled in a wide range, and high operation efficiency will be maintained.

In that case, during the cooling operation, dew may occur in the indoor heat exchanger (6) that serves as an evaporator, and in particular, depending on the indoor environment, dew may not occur due to adverse effects on the installed device. There are cases. In particular, since the optimum refrigerating effect is given when the refrigerant state is moist, it is highly probable that dew will occur when the control as in this embodiment is performed. here,
If the indoor heat exchanger (6) is provided with adiabatic characteristics or the amount of blown air is increased to prevent dew condensation as in the conventional case, the entire air conditioner is partially required because of some necessity. The design must be changed, resulting in design restrictions and increased costs.

On the other hand, in the first embodiment, the control target value of the discharge refrigerant temperature T ₂ from the external input is set to be more constant than the optimum temperature Tk as required by the user by switching the dew condensation prevention changeover switch (setting means) (Swa). The value is changed to a higher value. That is, as shown in the Mollier diagram of FIG. 5, the states of the intake refrigerant and the discharge refrigerant corresponding to the control target value are indicated by the broken lines on the right side from those states corresponding to the optimum temperature Tk (states indicated by solid lines). Since it shifts to the state, the suction refrigerant temperature T ₁ also rises. This means that the state of the sucked refrigerant changes from the gas-liquid boundary line toward the inside on the gas phase side and becomes a dry state.
Therefore, the refrigerant state at the outlet of the indoor heat exchanger (6) connected to the suction line is maintained on the dry side, the cooling capacity of the indoor heat exchanger (6) is reduced, and dew condensation is prevented. Become. Therefore, it is possible to effectively prevent the dew condensation of the indoor heat exchanger (6) without inviting design restrictions and cost increase.

In the first embodiment, the discharge pipe temperature T ₂ is the optimum temperature.
The control target value is set to the optimum temperature T by switching the dew condensation prevention switch (Swa) only when it converges within a certain range above and below Tk.
The value is set to be a value higher than k by a constant value (5 deg), but the present invention is not limited to this embodiment,
In all cases, the dew condensation prevention switch (Swa) may be switched to change the control target value to a value higher than the optimum temperature Tk by a certain value.

 Next, a second embodiment will be described.

FIG. 6 shows the configuration of the refrigerant piping system of the air conditioner according to the second embodiment. In addition to the same configuration as that of the first embodiment, the suction air humidity Rh of the indoor heat exchanger (6) is detected. Equipped with a humidity sensor (Hu).

Then, FIG. 7 shows the control contents of the controller, at step R _21, enter the value of the suction air humidity Rh detected by the humidity sensor (Hu), the first embodiment in steps R ₂₂ and R ₂₃ The same control as Steps R ₁ and R ₂ in step ₁ is performed. Then, in the determination of step R _23, discharge pipe sensor (Th
When 2) is not abnormal, the routine proceeds to step R ₂₄ , where it is determined whether or not the intake air humidity Rh detected by the humidity sensor (Hu) is higher than 80 (%) in step R ₂₄ , and Rh> 80.
(%) Unless, the same control as step R ₃ to R ₅ in the first embodiment at step R ₂₅ to R _27.

On the other hand, if Rh> 80 (%) in the determination in step R ₂₄ , the process proceeds to step R _28, and the value of the opening degree P of the electric expansion valve (5) is set based on the equation (4).

Then, thereafter, in steps R _{29 to} R ₃₄ , the same control as that in steps R _{7 to} R ₁₂ in the first embodiment is performed, and the control is ended.

In the above flow, when the humidity Rh of the intake air becomes higher than the predetermined value (80% in this embodiment) by the control of shifting from step R ₂₄ to step R ₂₈ , the control target of the discharge refrigerant temperature T ₂ in the opening degree control The value is calculated as the optimum temperature calculation means (5
The changing means (53) is configured to change the value of the optimum temperature Tk calculated in 1) to a value higher by a constant value (5 deg in the above embodiment).

Therefore, in the second embodiment, the humidity Rh of the intake air is detected by the humidity sensor (Hu), and when the intake air humidity Rh becomes higher than a predetermined value (80% in the above embodiment), the discharge pipe temperature in the opening control is controlled. since the control target value of T ₂ than the optimum temperature Tk has to be changed to a higher value by a predetermined value (5 deg), in particular, always maintains the cooling capacity of the indoor heat exchanger (6) by conventional control However, under conditions where dew condensation easily occurs, there is an advantage that the capacity of the indoor heat exchanger (6) can be automatically reduced to prevent dew condensation.

(Effect of the invention) As described above, according to the invention of claim (1),
In a refrigeration system equipped with a compressor, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger, during cooling operation, the optimum temperature calculated based on the evaporation temperature and condensation temperature of the refrigerant at that time is set to the discharge refrigerant temperature. While controlling the opening of the electric expansion valve as the control target value, the refrigerant state is maintained properly, while the control target value of the discharge refrigerant temperature is a value higher than the optimum temperature by an external input according to the user's selection. Since it is possible to maintain the refrigerant state on the outlet side of the indoor heat exchanger on the dry side to reduce its capacity, it is possible to prevent dew condensation without increasing design restrictions and cost. It is possible to effectively prevent the exposure of dew in an environment where it is unfavorable.

According to the invention of claim (2), in a refrigerating apparatus including a compressor, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger, during cooling operation, based on the evaporation temperature and condensation temperature of the refrigerant at that time. When the humidity of the suction air becomes higher than a predetermined value while maintaining the refrigerant state properly by controlling the opening of the electric expansion valve with the optimum temperature calculated as the control target value of the discharged refrigerant temperature, the discharged refrigerant temperature Since the control target value of is changed to a value higher than the optimum temperature value by a certain value, the capacity of the indoor heat exchanger is usually kept high, but under conditions where dew is likely to occur, it will automatically The evaporation capacity can be reduced to prevent dew condensation.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 5 show the first embodiment of the present invention, FIG. 2 is a refrigerant piping system diagram showing the configuration of the air conditioner, and FIG. 3 is the opening degree of the electric expansion valve during the cooling operation of the controller. FIG. 4 is a flow chart showing the main flow of control, FIG. 4 is a flow chart showing the sub-flow relating to the fuzzy control part of the main flow of FIG. 3, and FIG. 5 is a diagram for explaining the principle of optimal control of the discharge pipe temperature. Mollier diagram, FIGS. 6 and 7 show the second embodiment, FIG. 6 is a refrigerant piping system diagram showing the configuration of the air conditioner, and FIG. 7 is a sub-flow of the opening control of the electric expansion valve by the controller. It is a flowchart figure which shows the content of. 1 ... Compressor 3 ... Outdoor heat exchanger 5 ... Electric expansion valve 6 ... Indoor heat exchanger 9 ... Refrigerant circuit 51 ... Calculation means 52 ... Opening control means 53 ... Change means Swa ... Dew condensation prevention switch (setting means) Hu ... Humidity sensor (humidity detection means) Thc ... External heat exchange sensor (condensation temperature detection means) The ... Inner heat exchange sensor (evaporation temperature detection means) Th2 ... Discharge pipe Sensor (Discharge temperature detection means)

Claims (2)

[Claims] 1. An air conditioner comprising a refrigerant circuit (9) in which a compressor (1), an outdoor heat exchanger (3), an electric expansion valve (5) and an indoor heat exchanger (6) are sequentially connected. In the cooling operation, the evaporation temperature detecting means (The) for detecting the evaporation temperature of the refrigerant in the indoor heat exchanger (6), and in the cooling operation, detecting the condensation temperature of the refrigerant in the outdoor heat exchanger (3) Receiving the outputs of the condensation temperature detecting means (Thc) and the evaporation temperature detecting means (The) and the condensation temperature detecting means (Thc), the optimum refrigerating effect is obtained as a function of the evaporation temperature and the condensation temperature of the refrigerant at that time. A calculating means (51) for calculating the optimum temperature of the discharge refrigerant temperature to be given, a discharge temperature detecting means (Th2) for detecting the discharge refrigerant temperature, and the discharge temperature detecting means (Th2)
And an opening degree control means (52) for controlling the opening degree of the electric expansion valve (5) by using the optimum temperature calculated by the calculation means (51) as a control target value of the discharge refrigerant temperature. Setting for setting an external input to change the control target value of the discharged refrigerant in the opening control of the opening control means (52) to a value higher than the optimum temperature calculated by the calculation means (51) by a certain value An operation control device for an air conditioner, which is provided with means (Swa). 2. An air conditioner comprising a refrigerant circuit in which a compressor (1), an outdoor heat exchanger (3), an electric expansion valve (5) and an indoor heat exchanger (6) are sequentially connected, wherein: Evaporation temperature detection means (The) that detects the evaporation temperature of the refrigerant in the indoor heat exchanger (6) during operation, and condensation temperature that detects the condensation temperature of the refrigerant in the outdoor heat exchanger (3) during cooling operation A discharge refrigerant that receives the outputs of the detection means (Thc) and the evaporation temperature detection means (The) and the condensation temperature detection means (Thc), and gives an optimum refrigeration effect as a function of the evaporation temperature and the condensation temperature of the refrigerant at that time. Calculation means (51) for calculating the optimum temperature, discharge temperature detection means (Th2) for detecting the discharge refrigerant temperature, and discharge temperature detection means (Th2)
And an opening degree control means (52) for controlling the opening degree of the electric expansion valve (5) by using the optimum temperature calculated by the calculation means (51) as a control target value of the discharge refrigerant temperature. A humidity detecting means (Hu) for detecting the humidity of the intake air of the indoor heat exchanger (6) during the cooling operation, and the humidity detecting means (Hu).
When the humidity of the intake air exceeds a predetermined value by receiving the output of u), the control target value of the discharge refrigerant in the opening control of the opening control means (52) is set to the optimum temperature calculated by the calculation means (51). Change means to change the value by a certain value higher than (53)
An operation control device for an air conditioner, comprising: