JPH0498050A - Operation control device of refrigerating plant device - Google Patents

Abstract

PURPOSE:To improve a comfortable feeling of air conditioning while properly holding a refrigerant state and keeping a superior refrigeration effect by a method wherein the valve travel of an electrically driven expansion valve is controlled in such a way as a discharged refrigerant temperature may be converged into optimum temperature calculated in response to an evaporating temperature of the refrigerant at that time and a condensing temperature of the refrigerant and in turn as the discharged refrigerant temperature is converged into a specified range above and below the optimum temperature, the valve travel of the electrically driven expansion valve is controlled in response to a temperature difference between a sucked air temperature and its set value. CONSTITUTION:By an optimum temperature detection means 51, during operation of an air conditioning plant, optimum temperature Tk of a discharged refrigerant temperature T2 is calculated in response to a refrigerant evaporating temperature Te detected by an evaporating temperature sensing means The and a refrigerant condensing temperature Te detected by a condensing temperature detection means The. Then, the valve travel of an electrically- driven expansion valve 5 is controlled by a normal valve travel control means 52 in such a way as the discharging pipe temperature T2 is converged into the most appropriate temperature Tk. As the discharging pipe temperature T2 is converged into a specified range of the most appropriate temperature Tk, the valve travel of the electrically-driven expansion valve 5 is controlled by a discharging temperature converging valve travel control means 53 in response to a temperature difference between the suction air temperature detected by the suction temperature sensing means The and its set temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an operation control device for a refrigeration system, and particularly to measures for improving refrigeration efficiency.

(Prior Art) Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 59-12942, a refrigeration system equipped with a refrigerant circuit in which a compressor, a condenser, an electric expansion valve, and an evaporator are sequentially connected,
Compression is achieved by calculating the optimal discharge pipe temperature that provides the optimal refrigeration effect based on the evaporation temperature and condensation temperature of the refrigerant, and controlling the opening degree of the electric expansion valve so that the discharge pipe temperature converges to the optimal temperature. There are known techniques that attempt to ensure highly efficient operation without changing the operating capacity of the machine.

(Problems to be Solved by the Invention) As with conventional systems, by maintaining the discharged refrigerant in an appropriate state, the refrigerant circuit can operate smoothly without having to control the capacity of the compressor. The advantage of using a radial compressor is that it requires simple control. However, on the other hand, if the opening degree of the electric expansion valve is controlled using only the state quantity of the discharged refrigerant as a control index, depending on the operating conditions, the evaporator capacity may be left at a value far from the required capacity. There is a risk that the ability will not be fully satisfied.

The present invention has been made in view of the above, and its purpose is to control the evaporation capacity so that it corresponds to the required capacity while maintaining the state of the discharged refrigerant in an appropriate state.
The purpose is to improve the comfort of air conditioning.

(Means for solving the problem) To achieve the above object, the first means for solving the problem is as shown in Fig. 1A, a compressor (1), a condenser (3 or 6), an electric expansion valve (5) A refrigeration system is assumed to be provided with a refrigerant circuit (9) formed by sequentially connecting an evaporator (6 or 3) and an evaporator (6 or 3).

The evaporator (
6 or 3), and a condensing temperature detection means (T he) for detecting the condensation temperature of the refrigerant in the condenser (3 or 6).
he) and the outputs of the evaporation temperature detection means (T he) and condensation temperature detection means (T he), and determine the optimum discharge refrigerant temperature that provides the optimum refrigerating effect according to the evaporation temperature and condensation temperature of the refrigerant. Optimal temperature calculation means (51) for calculating temperature
), and a discharge temperature detection means (T
h2) and the output of the discharge temperature detection means (T h2), the electric expansion valve (5) is operated so that the discharge refrigerant temperature converges to the optimum temperature calculated by the optimum temperature calculation means (51).
A normal range opening control means (52) for controlling the opening of the opening is provided.

Furthermore, the suction temperature detection means (T hr) detects the temperature of the intake air of the evaporator (6 or 3), the suction temperature detection means (T hr) and the discharge temperature detection means (T h2).
), and when the discharge refrigerant temperature converges within a certain range above and below the optimum temperature calculated by the optimum temperature calculation means (51), the control of the normal range opening degree control means (52) is forcibly stopped. and a discharge temperature convergence region opening degree control means (53) for controlling the opening degree of the electric expansion valve (5) according to the suction temperature difference between the suction air temperature and its set value. be.

As shown in FIG. 1B, the second solution is based on a refrigeration system similar to the first solution, and uses evaporation temperature detection similar to the first solution as an operation control device for the refrigeration system. means (The), condensing temperature detection means (The),
Optimal temperature calculation means (51), discharge temperature detection means (Th2
) and normal range opening control means (52).

Further, there is a suction temperature detection means (Thr) for detecting the suction air temperature of the evaporator (6 or 3), and an output of the suction temperature detection means (Thr) is received so that the suction air temperature is set to a predetermined value above or below the set temperature. When it converges within the range, the control of the normal range opening degree control means (52) is forcibly stopped, and a predetermined weight is given to the temperature difference between the discharge refrigerant temperature and the optimum temperature and the temperature difference between the suction air temperature and the set temperature. A capacity convergence range opening degree control means (54) is provided for controlling the opening degree of the electric expansion valve (5) to be changed based on the calculated value.

(Function) With the above configuration, in the invention of claim (1), during operation of the refrigeration system, the optimum temperature calculation means (51) calculates the evaporation temperature of the refrigerant detected by the evaporation temperature detection means (The he) and the condensation temperature. The optimal temperature of the discharge pipe that provides the optimal refrigeration effect is calculated according to the condensation temperature of the refrigerant detected by the temperature detection means (The he).

Then, the opening degree of the electric expansion valve (5) is controlled by the normal range opening degree control means (52) so that the discharge refrigerant temperature converges to its optimum temperature, so the operating capacity of the compressor (1) is fixed. The refrigerant state in the refrigerant circuit (9) will be maintained in an appropriate state even if the refrigerant circuit (9) is closed.

In that case, if operation is performed based only on such a frozen state, the air conditioning request may be ignored, and the comfort of the air conditioning (i.e. When the discharge refrigerant temperature converges within a predetermined range above and below its optimum temperature, the temperature convergence range control means (53) detects the difference between the suction air temperature detected by the suction air temperature detection means (Thr) and its set temperature. Since the opening degree of the electric expansion valve (5) is controlled according to the temperature difference, the capacity of the evaporator (6 or 3) is controlled according to the required capacity, and the comfort of the air conditioning is improved. Become.

In the invention of claim (2), similarly to the invention of claim (1), the opening degree of the electric expansion valve (5) is controlled by the normal range opening degree control means (52), and the refrigerant state or the proper state is controlled. will be maintained.

At that time, when the suction air temperature detected by the suction temperature detection means (Thr) converges to its set value, the capacity convergence region opening control means (54) controls the suction air temperature of the evaporator (6 or 3). Based on the correlation between the change and the change in the discharge refrigerant temperature, the temperature difference between the discharge refrigerant temperature and its optimum temperature;
Since the opening degree of the electric expansion valve (5) is controlled according to a predetermined weighted value for the temperature difference between the intake air temperature and its set value, the refrigerant state or proper state is maintained. At the same time, the capacity of the evaporator (6 or 3) is maintained at a value corresponding to the required capacity, and reliability is improved by reducing the number of times the thermostat is switched on and off.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

Figure 2 shows the refrigerant piping system of an air conditioner to which the present invention is applied, in which (1) is a fixed capacity scroll type compressor;
(2) is a four-way switching valve that switches as shown in the solid line in the figure during cooling operation and as shown in the broken line in heating operation; (3) is a heat exchanger on the heat source side that functions as a condenser during cooling operation and as an evaporator during heating operation. (4) is an outdoor heat exchanger for storing liquid refrigerant; (5) is an electric expansion valve that has a refrigerant pressure reduction function and a refrigerant flow rate adjustment function;
(6) is an indoor heat exchanger that is installed indoors and functions as an evaporator during cooling operation and as a condenser during heating operation, and (7) is an indoor heat exchanger that is connected to the suction pipe of compressor (1). This is an accumulator for removing liquid refrigerant from the suction refrigerant.

The above-mentioned devices (1) to (7) are sequentially connected by refrigerant piping (8) to form a refrigerant circuit (9) in which heat transfer is caused by circulation of the refrigerant.

Here, an oil recovery device (10) for recovering oil in the discharged refrigerant is interposed on the discharge side of the compressor (1) of the refrigerant circuit (9), and the oil recovery device (10) Kara compressor (1)
- Oil skimmer (1) up to the suction pipe between the accumulator (7)
An oil return passage (11) is provided for returning the oil from compressor (1) to the suction side of the compressor (1). The Nioura return passage (11) is provided with an on-off valve (12) for opening and closing the passage, and while the on-off valve (12) is normally closed, the compressor (1) When the compressor (1) is started, it is opened under predetermined control to return part of the oil and discharged refrigerant from the oil recovery device (10) to the suction side of the compressor (1).

Further, in the liquid pipe of the refrigerant circuit (9), the receiver (
4) and the electric expansion valve (5) are connected to a common path (8) so that the electric expansion valve (5) communicates with the lower part of the receiver (4), that is, the liquid part.
a), and the point (P) which is the upper end of the receiver (4) of the common path (8a) and the outdoor heat exchanger (
3) is connected to the first inflow path (8b
), there is a second check valve (22) between the point (P) of the common path (8a) and the indoor heat exchanger (6) that allows the refrigerant to flow only to the receiver (4) side. and the second inflow path (8
C), while the common path (8a
) between a point (Q) that is the end of the electric expansion valve (5) side of the electric expansion valve (5) and a point (S) between the first check valve (21) and the outdoor heat exchanger (3).
The first outflow path (8d) via the first capillary tube (C1) connects the point (Q) of the common path (8a) and the second check valve (22) to the indoor heat exchanger (6). ) between the points (R
) are connected to each other by a second outflow path (8e) via a second capillary tube (C2).

That is, during cooling operation, liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) passes through the first check valve (21) and is stored in the receiver (4), and then flows through the electric expansion valve (5) and the second capillary. After being depressurized in the tube (C2), the indoor heat exchanger (6
) and return to the compressor (1), while during heating operation, the liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) passes through the second check valve (22) and returns to the receiver (4). is stored in the electric expansion valve (5) and the first capillary tube (C
After being depressurized in step 1), the air is evaporated in an outdoor heat exchanger (3) and then returned to the compressor (1) for circulation.

Note that (8f) is a liquid seal prevention bypass path provided in the first inflow path (8b) between point (P) and point (S) by bypassing the first reverse valve (21), A third capillary tube (C3) for reducing the pressure of the refrigerant is interposed in the liquid seal prevention bypass path (8f).

In addition, sensors are installed in the air conditioner,
(T h2) is a discharge pipe sensor which is arranged in the discharge pipe of the compressor (1) and serves as a discharge temperature detection means for detecting the discharge pipe temperature T, and (T he) is a liquid pipe of the outdoor heat exchanger (3). The external heat exchange sensor (T ha) is placed at the air suction port of the outdoor heat exchanger (3) and is used as a condensing temperature detection means to detect the evaporation temperature of the refrigerant during cooling operation, and detects the outside air temperature. The outside temperature sensor, (The he) is the indoor heat exchanger (6
), and serves as an evaporation temperature detection means for detecting the evaporation temperature Te during cooling operation.
) is placed at the air suction port of the indoor heat exchanger (6), and is an indoor suction sensor serving as a suction temperature detection means for detecting the suction air temperature T. The above-mentioned sensors control the operation of the air conditioner. The sensor is connected to a controller (not shown) so that signals can be input thereto, and the controller controls the operation of each device in accordance with the signals from the sensor.

Next, the control contents of the above-mentioned controller will be explained based on FIGS. 3 and 4.

Figure 3 shows the contents of EER control to maintain the maximum refrigeration effect EER during cooling operation, and shows step S1.
Then, the evaporation temperature Te detected by the internal heat exchange sensor (T he), the condensation temperature Tc detected by the external heat exchange sensor (T he), and the discharge pipe temperature T2 detected by the discharge pipe sensor (Th2) are Input each, and in step S2, enter the following (1
) Formula % Formula % (1) Based on the following, the optimum temperature Tk, which is the discharge pipe temperature that provides the optimum refrigeration effect EER, is calculated.

Next, in step S3, after calculating the temperature difference ΔT2 between the discharge pipe temperature T2 and the optimum temperature Tk based on the formula Δr2=T2−Tk, in step S4, it is determined whether 1ΔT21≦5, that is, whether the discharge pipe temperature T2 is It is determined whether or not the temperature has converged within a certain range above and below the optimum temperature Tk, and step S is continued until the temperature converges.
Proceed to step 5 and check whether ΔT2 is positive or not, that is, the discharge pipe temperature T2
The discharge pipe temperature T! is higher than the optimum temperature Tk. If it is higher, in step S6, the electric expansion valve (5)
If the discharge pipe temperature T2 is lower, the electric expansion valve (5) is controlled to be opened to a moderate degree in step S7.

On the other hand, in the determination in step S4 above, 1ΔT2≦5, and the discharge pipe temperature T:! When Tk converges within a certain range above and below the optimum temperature Tk, the process moves to step S8 and the following fuzzy control is executed.

That is, as shown in FIG. 4, in step R1, P-
After updating the opening drive pulse P of the electric expansion valve (5) as 1-P (P-1 is the previous drive pulse), in step R2, the discharge pipe sensor abnormality flag is set to "1" in the event of an abnormality. It is determined whether Ft2 is "1" or not, and if there is no abnormality, the process proceeds to step R3, where the temperature difference ΔTr between the intake air temperature T" detected by the indoor intake sensor (Thr) and the set temperature Trs is determined. , ΔTr −Tr−T during cooling operation
rs) is 25 deg or more, and Δ
If T"≧2.5, proceed to step R4 and perform the following (
2) Formula % Based on formula % (2), the drive pulse P for the opening of the electric expansion valve (5) is calculated. When it converges within the predetermined range, the process moves to step R5, and the drive pulse P for the electric expansion valve (5) opening degree is calculated based on the following equation (3). Now, the electric expansion valve (5) is opened based on the value obtained by weighting the temperature difference ΔT2 between the discharge pipe temperature lower 2 and the optimum temperature Tk and the temperature difference ΔTr between the suction air temperature Tr and the general constant temperature Trs in a ratio of 1:2. It is designed to control the degree of

Next, when the control in step R4 or R5 is finished,
Proceeding to step R6, it is determined whether or not IP+≦5, and if the commanded drive pulse P is small, it is determined that there is little need to change the control state, and the process returns to the main flow, while IPI≦5. If not, the process proceeds to step R7, and it is determined whether P>O. If P>0 and the command is to increase the opening degree of the electric expansion valve (5), in step RIO, it is determined whether P-1≦P, that is, the current drive pulse P
It is determined whether or not the current drive pulse is larger than the previous drive pulse P-1. If the current drive pulse is larger, in step R11, the opening degree of the electric expansion valve (5) is opened according to the drive command value P, and the current drive pulse is Drive command 1iI! If P is less than or equal to the previous drive command value P-1, the process returns to the main flow.

In addition, if P>0 is not determined in step R6, the process moves to step R8, and if the current drive command P is smaller than the previous drive command P-1, that is, the electric expansion valve (5)
If the opening degree change amount is larger this time, step R
9, the opening of the electric expansion valve (5) is controlled to close in accordance with the drive command P, while if the amount of change caused by the current drive command P is smaller, the opening of the electric expansion valve (5) is controlled to close. Return to the main flow without changing the opening.

In the above flow, by the control in step S2, an optimum temperature calculation means (51) is configured to calculate the optimum temperature Tk of the discharge pipe temperature that provides the optimum refrigeration effect according to the evaporation temperature Te and the condensation temperature Tc of the refrigerant. , steps 85-S7
normal range opening control means (52) for controlling the opening degree of the electric expansion valve (5) so that the discharge refrigerant temperature T2 converges to the optimum temperature Tk calculated by the optimum temperature calculation means (51); ) is configured.

Also, after proceeding from step R3 to R4, step R6~
When the discharge refrigerant temperature T2 converges within a predetermined range above and below the optimum temperature Tk calculated by the optimum temperature calculation means by the control that executes R1+, the normal range opening degree control means (52)
discharge temperature convergence range control that forcibly stops the control of the electric expansion valve (5) and controls the opening degree of the electric expansion valve (5) according to the suction temperature difference ΔT between the suction air temperature Tr and its set value Trs. means(
53) is configured.

On the other hand, in the invention of claim (2), steps R3 to R5
When the suction air temperature Tr converges within a predetermined range above and below the set temperature, the control of the normal range opening control means (52) is forcibly stopped by executing steps R6 to R1+. , capacity convergence range opening control that controls the opening of the electric expansion valve to be changed based on a value obtained by weighting the temperature difference between the discharge refrigerant temperature and the optimum temperature and the temperature difference between the suction air temperature and the set temperature with a predetermined weight; Means (54) are configured.

Therefore, in the above embodiment, during operation of the air conditioner,
The optimum temperature calculation means (51) calculates the evaporation temperature Te of the refrigerant detected by the internal heat exchanger sensor (evaporation temperature detection means) (The) and the external heat exchanger sensor (condensation temperature detection means) (T
According to the refrigerant condensation temperature Tc detected in he), the discharge refrigerant temperature T2 that provides the optimum refrigeration effect EER is calculated based on the above equation (1).

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 TI, and the outlet temperature is T, - (that is, When the discharge pipe temperature is TI, in polytropic compression, the following formula (4)% formula % [4] (where n is the polytropic index and the compressor (1)
(determined by the format, volume, etc.) holds true, the high pressure side pressure value Hp is the condensation temperature Tc, and the low pressure side pressure value Lp is the evaporation temperature Te.
By determining the optimum superheating degree sh to be, for example, about 2°C (see Figure 5, 2), T1 is determined from the relationship between T2 and T1, and as a result,
It will be expressed in the form of the following formula (5). In this embodiment, the discharge pipe temperature T that provides the optimum refrigeration effect EER was determined through experiments.
This optimum temperature Tk is expressed by the above equation (1).

Therefore, since the opening degree of the electric expansion valve (5) is controlled by the normal range opening degree control means (52) so as to converge to the discharge pipe temperature T2 or its optimum temperature Tk, the operating capacity of the compressor (1) can be reduced. Even if the refrigerant circuit (9) is fixed, the refrigerant state in the refrigerant circuit (9) is controlled within an appropriate range, and smooth operation is maintained.

In that case, if the operation is performed based only on such a frozen state, the air conditioning request may be ignored, and there is a risk that the comfort of the air conditioning will be impaired. However, the invention of claim (1) When the discharge pipe temperature T2 converges within a certain range above and below the optimum temperature Tk (in the above embodiment, ±5 deg (see Fig. 5)) by the discharge temperature convergence range control means (53), the indoor suction sensor (Suction temperature detection means) (Thr)
Since the opening degree of the electric expansion valve (5) is controlled according to the temperature difference ΔT between the intake air temperature Tr detected at Tr and its set temperature Trs, the amount of heat exchanged in the indoor heat exchanger (6) The capacity is controlled to match the required capacity, improving the comfort of air conditioning.

In the invention of claim (2), similarly to the invention of claim (1) above, the normal range opening degree control means (52)
), the opening degree of the electric expansion valve (5) is controlled and the refrigerant state is maintained in an appropriate state.

At that time, when the suction air temperature Tr detected by the suction sensor (Thr) has converged to its set value Trs, it is generally necessary to finely adjust the opening degree of the electric expansion valve (5), or It is necessary to satisfy both the required capacity and the suitability of the refrigerant condition.

By the way, there is generally a correlation between a change in the intake air temperature Tr of the indoor heat exchanger (6) and a change in the discharge pipe temperature T2. For example, in the case of this embodiment, experimental data shows that when the suction air temperature Tr increases by 1 degree, the discharge pipe temperature T2 increases by 2 degrees.

Here, in the invention of claim (2), the capacity convergence region opening control means (54) controls the discharge pipe temperature T2 and its optimum temperature T.
The opening degree of the electric expansion valve (5) is controlled based on the temperature difference ΔT2 between the intake air temperature Tr and the set value Trs, and the temperature difference ΔTr between the intake air temperature Tr and the set value Trs. That is, by performing control based on the fuzzy control production rule with the weighting of ΔTr and ΔT2 set to 2:1, as in equation (3) of the above embodiment,
The appropriate state of the refrigerant is maintained, and the capacity of the indoor heat exchanger (6) is ensured at a value corresponding to the required capacity. By doing so, while maintaining the comfort of air conditioning,
Reliability can be improved by reducing the number of times the thermostat is switched on and off.

In the above embodiments, the explanation has been given for the cooling operation of the air conditioner, but it goes without saying that the present invention can also be applied to the heating operation. This also applies to refrigerators.

Next, a second embodiment according to claim (3) of the invention will be described.

FIG. 6 shows the contents on the measurement side. In step Q1, from the signals of the indoor suction sensor (Thr) and the outdoor suction sensor (Tha), the indoor suction air temperature T "- the difference temperature ΔT of the set temperature.
r, the data of the indoor suction air temperature Tr and the outdoor suction air temperature Ta are input, and in step Q2, an abnormality determination flag is set, and in step Q3, the temperature difference that becomes "1" when the above temperature difference ΔTr is abnormal is set. It is determined whether the abnormality determination flag FΔTr is "0" or not, and if the temperature difference ΔTr is normal, the control is directly terminated, but if it is not normal, the process moves to step Q4 and the indoor suction sensor abnormality flag Ftr or "0", and if not normal, proceed to step Q5, and ΔT
As r-0, the thermostat is forcibly maintained in the thermo-on state.

On the other hand, in the determination in step Q4 above, the indoor suction sensor (T
hr) is normal, proceed to step Q6,
It is determined whether the outdoor suction sensor abnormality flag Fta, which becomes "1" when the outdoor suction sensor (Tha) is abnormal, is "0" or not, and if the outdoor suction sensor (Tha) is normal, step Q7, After cutting off the so-called (Ta-8) as (Ta-8)≧20('C), in step Q8, the following formula 5 (%) is used, and a re-alternative operation using the outdoor intake air temperature Ta is performed. conduct. In other words, when the temperature difference ΔTr is abnormal, there is an abnormality inside the microcomputer and an abnormality in the indoor suction sensor (Thr) itself.
If T hr) is normal, the temperature difference ΔTr is calculated using the outdoor intake air temperature Ta. In other words, this is based on the fact that normally, during cooling operation, it is comfortable when the room temperature is lower than the outside temperature by a predetermined value.

On the other hand, in the determination in step Q6 above, the outdoor suction sensor (T
ha) is abnormal, in step R9, ΔTr
The temperature difference ΔTr is calculated using the initial set 27 (° C.) as −Tr −27 .

(Effect of the invention) As explained above, according to the invention of claim (1), in a refrigeration system equipped with a refrigerant circuit formed by sequentially connecting a compressor, an evaporator, an electric expansion valve, and an evaporator, the discharge The opening degree of the electric expansion valve is controlled so that the refrigerant temperature converges to the optimal temperature calculated based on the evaporation temperature and condensation temperature of the refrigerant at that time, and when the discharge refrigerant temperature converges within a certain range above and below the optimal temperature. The opening degree of the electric expansion valve is controlled according to the temperature difference between the intake air temperature and its set value, so the refrigerant condition is maintained appropriately and a good refrigeration effect is ensured, while the comfort of the air conditioning is improved. It is possible to improve this.

According to the invention of claim 2, in a refrigeration system equipped with a refrigerant circuit in which a compressor, an evaporator, an electric expansion valve, and an evaporator are sequentially connected, While controlling the opening degree of the electric expansion valve so that it converges to the optimum temperature calculated based on the temperature, when the intake air temperature converges within a certain range above and below the set value, the discharge pipe temperature -
Since the opening degree of the electric expansion valve is controlled by a value that is weighted in a predetermined manner according to the temperature difference of the optimum temperature variable and the temperature difference between the suction air temperature and the set value, it is possible to It is possible to improve reliability by reducing the number of times the thermostat is turned on and off while finely controlling the temperature to an appropriate value.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. Figure 2 and subsequent figures show embodiments of the present invention, Figure 2 is a refrigerant piping system diagram showing the configuration of an air conditioner, Figures 3 and 4 show the control content of the controller during cooling operation, and Figure 3 The figure shows the main flow of controlling the electric expansion valve opening degree.
The figures are flowcharts showing subflows related to the fuzzy control part of the main flow, and FIG. 5 is a Mollier diagram for explaining the principle of optimal control of the discharge pipe temperature. 1 Compressor 3 Outdoor heat exchanger (condenser or evaporator) 5 Electric expansion valve 6 Indoor heat exchanger (evaporator or condenser) 9 Refrigerant circuit 51 Optimal temperature calculation means 52 Normal range opening control means 53 Discharge temperature convergence Inter-region degree control means 54 Capacity convergence region opening degree control means The External heat exchange sensor (condensing temperature detection means) The Internal heat exchange sensor (evaporation temperature detection means) Th2 Discharge pipe sensor (discharge temperature detection means) Thr Indoor suction sensor ( suction temperature detection means)

Claims (2)

[Claims] (1) In a refrigeration system equipped with a refrigerant circuit (9) formed by sequentially connecting a compressor (1), a condenser (3 or 6), an electric expansion valve (5), and an evaporator (6 or 3), the above-mentioned evaporation temperature detection means (The) for detecting the evaporation temperature of the refrigerant in the evaporator (6 or 3); condensation temperature detection means (Thc) for detecting the condensation temperature of the refrigerant in the condenser (3 or 6); Optimal temperature calculation that receives the outputs of the evaporation temperature detection means (The) and the condensation temperature detection means (Thc) and calculates the optimal temperature of the discharge refrigerant temperature that provides the optimal refrigeration effect according to the evaporation temperature and condensation temperature of the refrigerant. means(
51), and a discharge temperature detection means (
Th2) and the electric expansion valve (5) so that the discharge refrigerant temperature converges to the optimum temperature calculated by the optimum temperature calculation means (51) in response to the output of the discharge temperature detection means (Th2).
normal range opening degree control means (52) for controlling the degree of opening of the evaporator (6 or 3); Th
r) and the output of the discharge temperature detection means (Th2), and when the discharge refrigerant temperature converges within a certain range above and below the optimum temperature calculated by the optimum temperature calculation means (51), the normal range opening degree control means Convergence region opening control means (53) for forcibly stopping the control of (52) and controlling the opening of the electric expansion valve (5) according to the suction temperature difference between the suction air temperature and its set value. An operation control device for a refrigeration system, characterized by comprising: (2) In a refrigeration system equipped with a refrigerant circuit (9) formed by sequentially connecting a compressor (1), a condenser (3 or 6), an electric expansion valve (5), and an evaporator (6 or 3), the above-mentioned evaporation temperature detection means (The) for detecting the evaporation temperature of the refrigerant in the evaporator (6 or 3); condensation temperature detection means (Thc) for detecting the condensation temperature of the refrigerant in the condenser (3 or 6); Optimal temperature calculation means (51) receives the outputs of the evaporation temperature detection means (The) and the condensation temperature detection means (Thc) and calculates the optimum temperature that provides the optimum refrigeration effect according to the evaporation temperature and condensation temperature of the refrigerant. and a discharge temperature detection means (Th2) for detecting the discharge refrigerant temperature, and upon receiving the output of the discharge temperature detection means (Th2), the discharge refrigerant temperature converges to the optimum temperature calculated by the optimum temperature calculation means (51). normal range opening control means (52) for controlling the opening degree of the electric expansion valve (5), and suction temperature detection means (Thr) for detecting the suction air temperature of the evaporator (6 or 3). ), and the suction temperature detection means (Thr
) and the output of the discharge temperature detection means (Th2),
When the suction air temperature converges within a predetermined range above and below the set temperature, the control of the normal range opening degree control means (52) is forcibly stopped, and the temperature difference between the discharge refrigerant temperature and the optimal temperature and the suction air temperature are - A capacity convergence range opening degree control means (54) that controls the opening degree of the electric expansion valve (5) to be changed based on a value obtained by weighting a temperature difference between the set temperatures with a predetermined value. Operation control device for refrigeration equipment.