JPH03199874A - Forseeing of failure in refrigerating device - Google Patents

Abstract

PURPOSE:To permit repairing and/or maintenance with an enough time and avoid the interruption of operation by a method wherein the discharging pressure and the suction pressure of a compressor are compared with the normal discharging pressure and the normal suction pressure of the compressor, which are corresponding to the temperature of suction air, to judge and indicate a failure in a refrigerating device by the amount of differences. CONSTITUTION:The output data of a dry-bulb temperature sensor 23, a wet-bulb temperature sensor 24, another dry-bulb temperature sensor 25 and another wet-bulb temperature sensor 26 are inputted into a computer 28 through a signal converter 27. The function of normal operating pressure characteristics values Pdn, Psn having the parameters of air temperature conditions (dry-bulb and wet-bulb temperatures) inside and outside of a room for every kinds of heat pump type air-conditioning machines previously are inputted into the computer 28 while the computer 28 is provided with a sequence, which operates the normal operating pressure characteristic values Pdn, Psn of the air-conditioning machine by the dry-bulb temperatures T11, T21 of suction air inside and outside of the room as well as the wet-bulb temperatures T12, T22 of the same and judges the condition of the failure of the heat pump type air-conditioning machine by comparing the values Pdn, Psn with the characteristic values Pd, Ps of actual operating pressures. Then, the abnormality of the heat pump type air- conditioning machine 1 is classified and indicated as failures, written in a data processing routine respectively, by the AND conditions of two elements of the discharging pressure Pd and the suction pressure Ps.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention provides a method for refrigeration equipment, such as a heat pump air conditioner or a store refrigerator-freezer, to notify the operation abnormality of the refrigeration equipment at an early stage before the equipment stops due to failure. This relates to a failure prediction method.

(Background of the Invention) Refrigeration equipment such as heat pump air conditioners having a refrigeration cycle is used in all fields today.
Moreover, the terms of use are becoming increasingly strict.

For example, convenience stores that are open 24 hours a day have become commonplace, and since these stores are open all year round, the air conditioners, refrigerators and freezers used in these stores can operate 24 hours a day without failure throughout the year. This is required.

However, in general, the air filter installed at the air intake port of the indoor heat exchanger is likely to become dirty due to dust and other factors that occur when customers come and go in stores, and bacteria can grow on the surface of the heat exchanger, producing slime. . Although it is recommended that users regularly clean their air filters once a week, the reality is that this is rarely done.

As a result, in conventional air conditioners, the air volume of the indoor heat exchanger decreases, reducing the heating and cooling capacity, or the high/low pressure cutoff switch, which is a protective device, is activated, causing the compressor to suddenly stop. There was a problem.

FIG. 3 is a diagram showing the operating pressure range and stress range of a standard compressor of a heat pump type air conditioner.

Generally, compressors for air conditioners have a discharge pressure of 28 kg/cm.
The area surrounded by the pressure range of 2G or more and the suction pressure of 0.2kg/cm2G or less, and the area where the compression ratio C (ratio of discharge pressure to suction pressure at absolute pressure) is 8 or more is excluded from the normal operating range as a stress area. In order to maintain the reliability of the compressor, various protection devices are used to stop the compressor in this stress region.

The pressure area surrounded by a diamond in Figure 3 is the operating pressure area during standard heating and cooling operation within the indoor and outdoor temperature range specified by the JIS standard, and heat pump air conditioners are operated as long as there is no abnormality. The high and low pressure characteristics within this region are shown. Note that the x mark is a design point.

High pressure abnormality occurs during cooling operation, when the fan motor of the outdoor blower fails and the standard air volume cannot be secured, or when the condenser capacity decreases due to dirt on the outdoor heat exchanger, etc. Occurs on the side. In the case of this high pressure abnormality, the high pressure cutoff switch installed in the discharge pipe of the compressor opens the contacts of the compressor's electrical circuit and stops the power supply to the compressor when the pressure reaches 28 kg/cm2G or more. do.

Conversely, during heating operation, the indoor heat exchanger acts as a condenser, so there may be dirt on the air filter installed at the air intake port, dirt on the surface of the indoor heat exchanger, or the fan of the indoor blower. The discharge pressure increases due to a decrease in the required air volume due to motor failure, and the high-pressure cutoff switch operates to stop the compressor, similar to during cooling operation.

In addition, low pressure abnormality occurs when the amount of refrigerant in the refrigeration cycle decreases, or when the air volume of the heat exchanger that acts as an evaporator decreases, the low pressure decreases to 0.2 kg/cm"G or less. At times, the compressor is stopped by opening the contacts of the low pressure cutoff switch provided in the suction pipe of the compressor.

Furthermore, conventional protection mechanisms for avoiding high-pressure compression ratio operation ranges include: - Since the gas temperature at the compressor outlet increases as the compression ratio increases during boat fishing, a discharge gas thermostat usually installed in the compressor discharge pipe is used. The temperature is detected by 130
℃ or above by opening the electrical circuit contacts to stop compressor operation, and by operating an internal overload protector attached to the windings of the compressor motor inside the compressor. It is protected by one of the methods of stopping and stopping energization.

In any case, the conventional protection mechanism for air conditioners is based on a method of stopping operation by cutting off the electric circuit of the compressor depending on protection conditions.

Conventional general air conditioner maintenance services include:
A service call is received only after an abnormality occurs, and countermeasures are taken after the cause of the problem has been determined, so it takes a lot of time to recover from the problem, resulting in a long period of time without air conditioning.

Many products sold at convenience stores lose their value due to melting at room temperature in the summer, and sudden failure of air conditioners not only makes it impossible to maintain proper air conditioning in these stores. There was also the issue of maintaining product quality.

(Objective of the Invention) An object of the present invention is to provide a malfunction prediction method for a refrigeration system that solves the above-mentioned problems, allows repair and maintenance to be carried out with sufficient time, and avoids operation stoppage. It is.

(Features of the Invention) In order to achieve the above object, the present invention detects the suction air temperature of the indoor heat exchanger and the outdoor heat exchanger, and also detects the discharge pressure and suction pressure of the compressor. The normal discharge pressure and normal suction pressure of the compressor corresponding to the suction air temperature are derived, and the detected discharge pressure and suction pressure are compared with the normal discharge pressure and normal suction pressure, and the problem is detected based on the amount of deviation. The system is characterized in that it determines and displays the malfunction, thereby notifying the user of the malfunction before it leads to the suspension of operation.

(Embodiments of the Invention) FIG. 1 is a configuration diagram of an example of a heat pump type air conditioner and its malfunction prediction system implementing the present invention.

A heat pump type air conditioner l consists of a compressor 2, a discharge pipe 3 of the compressor 2, a four-way valve 4 that changes the flow of refrigerant, and an outdoor heat pump that operates as a condenser during cooling operation and as an evaporator during heating operation. Exchanger 5, check valve 6 that opens during cooling operation, heating expansion valve 7, cooling expansion valve 8, check valve 9 that closes during cooling operation, operates as an evaporator during cooling operation, and acts as a condenser during heating operation. The indoor heat exchanger 10, the accumulator 11, and
It is composed of a suction pipe 12 of a compressor 2. Note that the outdoor heat exchanger 5 is provided with an outdoor fan 13, and the indoor heat exchanger 10 is provided with an indoor fan 14.

In the system configured as above, during cooling operation,
The refrigerant circulates in the order of 2 → 3 → 4 → 5 → 6 → 8 → 10 → 4 → 11 → 12 → 2, and during heating operation, 2-3
The refrigerant circulates in the order of →4→10→9→7→5→4→11→12→2 to form a refrigeration cycle.

Here, the operating pressure characteristics during normal operation of the heat pump type air conditioner are the wet bulb temperature of the intake air of the indoor heat exchanger 10 and the dry bulb temperature of the intake air of the outdoor heat exchanger 5 during cooling operation. It is given as a function of temperature, and if the outdoor suction dry bulb temperature is T1°C and the indoor suction wet bulb temperature is T2°C, then the operating pressure characteristic value during normal operation, that is, the normal discharge pressure P
dn and normal suction pressure P%6 are expressed by the following formula.

P, l, = F (T,, dingzt) = a+bTl
++c(1'9.5-T22) 10dLog(T+ +)
+e(19,5-T5-Ta2)Lo+ +)Ps,,
= F (T+ l, Tzs) = f+gT+ ++h
(19,5-T22)+iLog(T++)+j(19
, 5-75-72s) Lo++) However, a, b, c
, d, e, f, g, h, i, and j are constants determined for each model. Therefore, by knowing the outdoor suction dry bulb temperature T and the indoor suction wet bulb temperature T22, the temperature under each temperature condition can be determined. The normal operating pressure characteristic values of heat pump air conditioners can be calculated.

In addition, the normal operating pressure characteristic value during heating operation is the same as that during cooling operation.If the outdoor suction wet bulb temperature is T12℃, and the indoor suction dry bulb temperature is T2 + "c, then the operating pressure during normal operation is The characteristics, that is, the normal discharge pressure Pdh and the normal suction pressure Pan are given by: P, I, = F (T, □, T2.) P, h = F (T, 2. T2.) In the case of cooling operation The normal operating pressure characteristic value can be calculated in the same manner.

That is, the calculation of the operating pressure characteristic value during normal operation of the refrigeration equipment is based on T z and T 22 or T I2 and T 21.
This is possible by knowing two temperature elements.

In the embodiment shown in FIG. 1 which implements the present invention based on the above principle, a high-pressure pressure sensor 21 for detecting the discharge pressure is provided in the discharge pipe 3 of the compressor 2 constituting the refrigeration cycle, and the suction pipe of the compressor 2 12 is provided with a low-pressure pressure sensor 22 that detects the suction pressure, and also detects the dry bulb temperature T of the outdoor suction air.
A dry bulb temperature sensor 23 that detects I+, a wet bulb temperature sensor 24 that also detects the wet bulb temperature TI2, a dry bulb temperature sensor 25 that detects the dry bulb temperature T21 of the indoor intake air,
Also, a wet bulb temperature sensor 26 is installed to similarly detect the wet bulb temperature T22.

Note that the output data of each of these sensors 23 to 26 is input manually to a computer 28 via a signal converter 27.

A function of normal operating pressure characteristic values Pdn+Psn with indoor and outdoor air temperature conditions (wet and dry bulb temperature) as a parameter is input in advance to the computer 28 for each model of heat pump type air conditioner. The normal operating pressure characteristic value Pdn+ ps□ of the air conditioner is calculated from the suction dry bulb temperature T u + 721 and the wet bulb temperature T1□, T22, and this value is compared with the actual operating pressure characteristic value p, , p, As a result, it has a sequence for determining the malfunction status of heat pump type air conditioners.

FIG. 2 is a flow diagram showing a data processing routine during cooling operation of the failure prediction system for the heat pump air conditioner 1, which implements the present invention.

The outdoor suction dry bulb temperature Tz (°C) and the indoor suction wet bulb temperature T2□ (°C) are determined by the temperature sensor 23.2, respectively.
6, and in steps ■ and ■ of the flowchart of FIG. 2, the normal operating pressure characteristic value under the suction air conditions of the outdoor suction dry bulb temperature T and the indoor suction wet bulb temperature T22 is They are calculated using arithmetic expressions stored in the computer 28, and Pd, , and P, , (
kg/cm'G).

On the other hand, the discharge pressure P of the discharge pipe 3 of the compressor 2 and the suction pipe 1
The suction pressure P of 2 is the actual operating pressure characteristic value (kg/cm2G) under the conditions of Tz and T22, and is obtained as a signal from the high pressure pressure sensor 21 and the low pressure pressure sensor 22, respectively. It is input to a computer 28 via a converter 27.

Hereinafter, conditions for determining failure prediction of the heat pump type air conditioner 1 will be explained.

Step (2) is to judge the allowable pressure range caused by a refrigerant filling error during on-site construction of the heat pump air conditioner 1, and the discharge pressure P and suction pressure P5 are respectively Pdh-0, 7≦Pd≦ Pd,,+0.7P,h
−(1, 2≦P, ≦P, l, +0.2 is the normal operating range.

Therefore, if both P and P are within the above operating pressure range, the malfunction prediction system displays "normal operation" on the display in step (3) and continues monitoring.

1 2 If the normal operating range is exceeded in step ■, proceed to step ■, and in step ■, the discharge pressure decrease and suction pressure are determined respectively due to a decrease in the evaporator workload when the fan stops due to a failure of the indoor blower 14. Determine the decline. That is, in step (3), if the discharge pressure P and the suction pressure P are P, ≦ P, l, −4,5 P, ≦ P, , −1,0, the failure prediction system is " in step ■"
"Low pressure abnormality" is displayed.

If the above conditions are not met in step ■, proceed to step
, 10 is determined to be a decrease in the discharge pressure Pd and suction pressure P due to gas leakage from cracks or pinholes. That is,
The discharge pressure P and the suction pressure P are respectively PdI, 4.5 <p, ≦P, l, -1,3P, I, -
If 1, 0<P, ≦p, , -o, 4, the malfunction prediction system displays "gas shortage" in step (3) and prompts an inspection for the presence or absence of cracks. High and low pressure conditions from appropriate refrigerant filling conditions to low pressure abnormal conditions correspond to this range.

If the above conditions are not satisfied in step (2), the process further proceeds to step 0, where it is determined whether the cooling capacity has decreased due to a decrease in air volume due to the dirty coils of the indoor heat exchanger 10 or the dirty air filter. In other words, the air volume is 75% of the standard value.
%, the area where the cooling capacity decreases by 5% is the discharge pressure P and the suction pressure P, respectively.
dI, -1,3<p, ≦Pdh-0,7P, I, -0,
If 4<P, ≦P, h-0,2, the malfunction prediction system displays "indoor coil dirt, filter clogging" in step (3) and prompts inspection.

If the above conditions are not met in step (2), the process further proceeds to step [phase], where the discharge pressure P is increased until the air volume of the outdoor fan 13 drops to 75% of the standard value, and the suction pressure is increased accordingly. A rise in P is determined, and a decrease in the air volume of the outdoor fan 13 is determined. This operating condition is the same even when the amount of refrigerant charged is excessive, and the discharge pressure P and suction pressure P, , are Pdh+0.7 <Pa≦Pdh+1.4Ps+, +0, respectively.
．． 2 If <Ps≦P, . . . + 0.4, the malfunction prediction system displays "Outdoor coil dirty, refrigerant overfill" in step (■).

If the above conditions are not satisfied in step 0, the process further proceeds to step (2), where it is determined that the pressure is within the high pressure operating range. That is, the discharge pressure Pd and the suction pressure P are
If P, +fi+1.4 <Pd≦28 P,I,+0.4 <P,≦7.0, respectively, the failure prediction system performs step [phase]
Displays "high pressure abnormality" and prompts for early maintenance.

If the above conditions are not met in step
Since the compressor is operating in the stress region shown in the figure, the malfunction prediction system determines that there is an "equipment abnormality" in step (3).

In short, the abnormality of the heat pump type air conditioner 1 is classified into the malfunctions described in the flow diagram of the data processing routine shown in FIG. and display it.

As mentioned above, in conventional heat pump air conditioners,
From the perspective of ensuring the reliability of the compressor, the system operates while avoiding stress areas, so if an abnormality occurs in the equipment and it enters a stress operation state, the equipment is immediately stopped. According to the system shown in Figure 1,
Appropriate maintenance and inspection can now be carried out in a timely manner before the heat pump air conditioner stops working, making it possible to avoid sudden stoppages in stores that are open 24 hours a day, and leaving the store open without air conditioning. , it is possible to avoid deterioration in the quality of products in the store.

Although the above detailed description of the present invention has been directed to a heat pump type air conditioner, the present invention is equally applicable to reach-in devices such as cooling-only air conditioners having a refrigeration cycle and refrigerator-freezers for stores. The following effects can be obtained.

Furthermore, by installing a host computer in the headquarters structure and transmitting temperature and pressure signals from each store's air conditioning equipment to the headquarters via telephone lines, the headquarters can remotely detect malfunctions in the air conditioning equipment at each affiliate store. It becomes possible to perform predictive management, saving labor and establishing an efficient service system.

(Effects of the Invention) As described above, according to the present invention, the suction air temperature of the indoor heat exchanger and the outdoor heat exchanger is detected, and the discharge pressure and suction pressure of the compressor are detected. The normal discharge pressure and normal suction pressure of the compressor corresponding to the suction air temperature are derived, and the detected discharge pressure and suction pressure are compared with the normal discharge pressure and normal suction pressure, and the problem is detected based on the amount of deviation. A malfunction prediction method for refrigeration equipment that can determine and display malfunctions and notify malfunctions before they occur, allowing repairs and maintenance to be carried out with plenty of time and avoiding operational shutdowns. can be provided.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an example of a heat pump air conditioner and its malfunction prediction system implementing the present invention, Fig. 2 is a flow diagram showing the data processing routine of the malfunction prediction system during cooling operation, and Fig. 3 is a flow diagram of an example of the malfunction prediction system. FIG. 2 is a diagram showing the operating pressure range and stress range of a standard compressor of a heat pump type air conditioner. 110. Heat pump air conditioner, 21. . Compressor, 3.1. discharge pipe, 400. Four-way valve, 5°1. Outdoor heat exchanger, 611. Check valve, 713. Heating expansion valve, 811. Expansion valve for cooling, 911. Check valve, 10. , , indoor heat exchanger, 11. , ,
Accumulator, 12. ,. Suction pipe, ia, outdoor blower, 14. ,, indoor blower, 21. ,,Discharge pressure sensor, 22°,, +1 person pressure sensor, 23. ,,outdoor dry bulb temperature sensor, 24. ,
, outdoor wet bulb temperature sensor, 2513. Indoor dry bulb temperature sensor, 26. ,, indoor wet bulb temperature sensor, 27. ,,signal converter,28゜1. Computer.

Claims (2)

[Claims] (1) Detect the temperature of the suction air of the indoor heat exchanger and the outdoor heat exchanger of a refrigeration system having a refrigeration cycle, and also detect the discharge pressure and suction pressure of the compressor of the refrigeration system, and detect the temperature of the suction air. Determine the normal discharge pressure and normal suction pressure of the compressor corresponding to the compressor, compare the detected discharge pressure and suction pressure with the normal discharge pressure and normal suction pressure, and determine and display the malfunction based on the amount of deviation. A malfunction prediction method for refrigeration equipment. (2) Detect the intake air temperature of the indoor heat exchanger and the outdoor heat exchanger at dry bulb temperature and wet bulb temperature, respectively, and detect the normal discharge pressure and normal suction pressure of the compressor. 2. The malfunction prediction method for a refrigeration system according to claim 1, wherein the calculation is performed as a function of the dry bulb temperature and the wet bulb temperature of the intake air of the outdoor heat exchanger.