JP2001021195A - Contamination detecting system for heat exchanger of air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a contamination detecting system for heat exchanger of air conditioner in which abnormal stop due to pressure rise incident to lowering of heat exchanging efficiency based on accumulated contaminant in the heat exchanger is prevented. SOLUTION: The contamination detecting system comprises refrigerant inlet and outlet temperature sensors 8, 9 of an outdoor heat exchanger 2, suction and delivery air temperature sensors 10, 11 of an outdoor unit, a high pressure sensor 6 for refrigerant circuit, means for detecting contamination of a heat exchanger based on the detection values of these sensors, and means for informing contamination based on the output from the contamination detecting means. The contamination detecting means receives detection value from each sensor every predetermined time and calculates a heat passing rate as the degree of contamination of the heat exchanger, accumulates the detection value from each sensor and the calculated heat passing rate, calculates a criterion for determining the degree of contamination of the heat exchanger based on the accumulated data, compares the heat passing rate with the criterion, and actuates the informing means if the heat passing rate is lower than the criterion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dirt detection system for a heat exchanger of an air conditioner, and more particularly to a system for detecting in advance the dirt condition of an outdoor heat exchanger of an air-cooled packaged air conditioner.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a cooling refrigerant circuit of a conventionally used air conditioner. In FIG. 5, 1
Is a compressor, 2 is an outdoor heat exchanger (condenser), 3 is an expansion valve,
Reference numeral 4 denotes an indoor heat exchanger (evaporator), and a single refrigerant circuit is formed by these configurations. Reference numeral 5 denotes a high pressure switch which operates when the high pressure is increased, 6 denotes a high pressure sensor, 7
Is a bypass solenoid valve for bypassing from the high voltage circuit side to the low voltage circuit side when the high voltage rises.

Next, the operation of the above configuration will be described. In the refrigerant circuit configured as described above, when the outside air temperature is high during the cooling operation, the high pressure tends to increase with the operation, and further, when the aging dirt is accumulated in the outdoor heat exchanger 2. In many cases, the high-pressure switch 5 is operated to stop the compressor 1 abnormally. Depending on the model,
The bypass solenoid valve 7 opens according to the pressure detected by the high-pressure sensor 6 to suppress a high-pressure rise.

[0004]

As described above, due to the rise in the outside air temperature and the dirt on the outdoor heat exchanger 2, the high pressure rises and stops abnormally, and an air conditioner (hereinafter simply referred to as an air conditioner) is used. Becomes impossible. Further, when the bypass solenoid valve 7 is opened, there is a problem that the cooling capacity is reduced and the cooling is not performed.
As a permanent measure, the task of cleaning the heat exchanger will be explained to the user, but not only will the user not be able to use the air conditioner but also will have a sudden expense in this operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and detects a dirt accumulated in a heat exchanger over time, thereby reducing the heat exchange rate. It is an object of the present invention to obtain a heat exchanger dirt detection system for an air conditioner that can prevent abnormal stop due to high pressure rise.

[0006]

A heat exchanger dirt detection system for an air conditioner according to the present invention comprises an inlet temperature sensor and an outlet for detecting a refrigerant inlet temperature and a refrigerant outlet temperature of an outdoor heat exchanger of an air conditioner, respectively. A temperature sensor, an outdoor unit intake air temperature sensor and an outdoor unit outlet air temperature sensor that respectively detect an intake air temperature and an outlet air temperature of the outdoor heat exchanger, and a high pressure sensor that detects a high pressure of a refrigerant circuit of the air conditioner. And a dirt detecting means for detecting dirt on the heat exchanger based on the detection values of these sensors; and a notifying means for notifying dirt based on an output from the dirt detecting means. Input the detection value of each sensor at regular intervals, calculate the heat transmission rate as the degree of contamination of the heat exchanger, and accumulate the detection value of each sensor and the calculated heat transmission rate. A reference value for determining the degree of contamination of the heat exchanger is calculated based on the accumulated data, and the heat transmission rate is compared with the determination reference value. Is operated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a refrigerant circuit diagram of a heat exchanger dirt detection system for an air conditioner according to Embodiment 1 of the present invention. 1, the same parts as those of the conventional example shown in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. As a new code, 8 and 9 are an inlet temperature sensor and an outlet temperature sensor for detecting a refrigerant inlet temperature and a refrigerant outlet temperature of the outdoor heat exchanger 2, respectively, and 10 and 11 are an inlet air temperature and an outlet air of the outdoor heat exchanger 2, respectively. An outdoor unit intake air temperature sensor and an outdoor unit outlet air temperature sensor for detecting temperatures, respectively, and the detection signals of these sensors 8 to 11 and the high pressure sensor 6 are used for dirt detection by a heat exchanger dirt detection device described later.

FIG. 2 is a diagram showing the internal configuration of the heat exchanger dirt detection device. As shown in FIG. 2, the heat exchanger dirt detection device 20 includes an input device 12 for inputting a detection signal and a set value of each sensor shown in FIG. 1, a heat transfer coefficient used for determining the degree of dirt of the heat exchanger, and A computing device 13 for computing the determination reference value and the like; a storage device 14 for storing and accumulating data input by the input device 12 and computation data by the computing device 13; a comparing device 15 for determining the degree of contamination of the heat exchanger; And a control unit 16 for controlling each component, and when the heat transmission rate falls below the determination reference value, operates the notifying device 17 based on the output from the comparing device 15 to notify the detection of dirt. ing.

Next, the operation according to the above configuration will be described with reference to FIG.
This will be described with reference to the characteristic diagram of the heat transfer coefficient in the heat exchanger shown in FIG. 4 and the operation flowchart of the heat exchanger contamination detecting device 20 (mainly the control unit 16) shown in FIG. Outdoor heat exchanger 2
Is secular dirt accumulates when multiple years use, as shown in FIG. 3, cleanliness is severely each overlapping age, the value of heat transfer coefficient K is, as the initial value K ₀ of K _n It gradually decreases.

Therefore, the high-pressure pressure, the refrigerant inlet temperature, the refrigerant outlet temperature, the outdoor unit intake air temperature, and the blow-out air temperature of the outdoor heat exchanger 2 are detected by the respective sensors and input by the input device 12 at regular intervals. Then, the heat transmission coefficient K is periodically calculated by the arithmetic unit 13 according to the following formula.

Condensing capacity Q = K · A · ΔT ΔT = T _c − (T ₁ + T ₂ ) / 2 Condensing capacity Q = G · Δh where, condensing capacity Q, heat transfer area A, refrigerant circulation amount G is a set value, condensing temperature _Tc is a value obtained from the detection value of the high pressure sensor 6, and the enthalpy difference of the refrigerant inlet / outlet portion of the outdoor heat exchanger 2 △
h is the detected value of the enthalpy value obtained from the difference between the enthalpy corresponding to the detected value by the temperature sensor 9, T ₁ and T ₂ are the temperature sensor 10 11 that corresponds to the detected value by the temperature sensor 8, the arithmetic average temperature The difference ΔT can be calculated.

The heat transmission coefficient K obtained by the calculation of the arithmetic unit 13 is periodically stored as heat exchanger stain data together with the condensing temperature T _c , the outdoor unit intake air temperature T ₁ , and the outdoor unit outlet air temperature T _2. Is accumulated in Further, each time such data is accumulated, the limit value K ′ of the heat transmission rate with respect to the high-pressure cut value of the air conditioner is calculated by the calculation device 13 based on the following equation.

K ′ = Q / (A · ΔT) = (Q / A) ·
[T _c ′ − (T _1MAX + T _2MAX ) / 2] Here, T _c ′ is a condensation temperature (set value) with respect to the high-pressure cut value of the air conditioner, and T _{1 MAX} and T _2MAX take into account the high temperature in summer. outdoor unit inlet air temperatures T ₁ is stored in the storage device 14 and, among the data of the outdoor unit outlet air temperature T _2, respectively using the maximum temperature.

The limit value K 'of the heat transfer rate with respect to the high-pressure cutoff value of the air conditioner obtained as described above is used as a criterion value for contamination of the heat exchanger, and the heat transfer rate K and the criterion value K' are determined by the comparator 15. When the value of the heat transfer rate K is lower than the determination reference value K ′, it is determined that the heat exchanger is likely to be contaminated and a high pressure abnormality is likely to occur. Notify. Further, it is also possible to incorporate a notifying device in the notifying device 17 so as to notify a predetermined notifying destination.

The control unit 16 can set the heat transfer area A, the high pressure cut value (condensation temperature Tc '), and change the reset setting of the initial value. If the setting mode, the value of heat transfer coefficient at that time as an initial value K _0, the current overall heat transfer coefficient K _n is compared with the initial value K _0, i.e. efficiency _{η n = K n / K 0} × 10
By obtaining 0, the status of the heat exchanger contamination can be grasped.

FIG. 4 is a flowchart showing the control operation of the control unit 16 described above. That is, as shown in FIG. 4, first, as the set values, the condensing capacity Q, the heat transfer area A, and the refrigerant circulation amount G are input through the input device 12, and the built-in timer is initialized to t = 0 ( Step S1, S
2). Further, it is determined whether or not the input setting mode is the initial setting mode (step S3). After passing through the initial setting mode determination step, the built-in timer sets the predetermined time t _re.
The count is repeated periodically every time.

In the initial setting mode, n = 0 is set (step S4a), and when the repetition time t _re has been reached, the high-pressure pressure sensor 6, the outdoor unit intake air temperature sensor 10, and the outlet air temperature sensor 11 are detected as detection data. Are input (steps S5 and S6), and the arithmetic unit 13 calculates the heat transmittance K _n and the efficiency η _n (K _n / K ₀ × 100) and stores them in the storage unit 14. (Step S7). In this case, the heat transmittance and the efficiency are denoted as K ₀ and η ₀ , but are not stored because η ₀ is 100% and has no meaning.

Next, when n = 0, the process shifts from step S8 to step S2, sets the built-in timer to t = 0, and then shifts to step S4b because the mode is not the initial setting mode. After counting up and reaching the repetition time t _re , detection data of the high pressure sensor 6, the refrigerant inlet temperature sensor 8, the refrigerant outlet temperature sensor 9, the outdoor unit intake air temperature sensor 10, and the blowout air temperature sensor 11 are detected data. enter the detection value (step S5, S6), the overall heat transfer coefficient K _n and efficiency eta _n computed by the computing unit 13, the storage device 1
4 (step S7).

In this case, since n = 0 is not satisfied, the process goes through step S8 and shifts to step S9, where the limit value K 'of the heat transfer rate with respect to the high pressure cut value of the air conditioner is calculated and stored in the storage device 14. (Step S9).

Through these steps, the storage device 14
Heat transfer coefficient K _n to other sequential detection data, the efficiency η operation update data of the operation data and the limit value K 'of _n is stored in each case, the comparator 15 and the overall heat transfer coefficient K _n criterion value K Are compared (step S10), and if the value of the heat transfer rate K is lower than the determination reference value K ', the heat exchanger becomes dirty,
It is determined that the possibility of high pressure abnormality is high, and the user is notified from the notification device 17 as a sign (step S1).
1). In addition, a notification device is built in the notification device 17 to notify a predetermined notification destination.

Therefore, according to the above-described embodiment, by providing the heat exchanger dirt detection device 20 having the above-described configuration in the packaged air conditioner, it is possible to determine the degree of dirt of the heat exchanger over time. is there. Further, when the contamination exceeds the allowable range, the user can be notified in advance as a sign without abnormal stop. As a result, it is possible to prevent sudden expenditures for the heat exchanger cleaning operation. Further, since the degree of contamination (efficiency η) of the heat exchanger can be grasped at any time, the notification to the user also facilitates the explanation to the user.

[0022]

As described above, according to the present invention, the degree of contamination of the heat exchanger can be grasped at any time by detecting the degree of contamination from the operation data, storing it as data, and comparing it with the limit value. If it is determined that the possibility of a high-pressure abnormal stop due to heat exchanger contamination is high before the abnormal stop, the user can be notified as a sign.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a heat exchanger dirt detection system for an air conditioner according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing an internal configuration of a heat exchanger dirt detection device according to Embodiment 1 of the present invention.

FIG. 3 is a characteristic diagram of a heat transmittance in a heat exchanger.

FIG. 4 is an operation flowchart of the heat exchanger dirt detection device 20 (mainly the control unit 16) according to Embodiment 1 of the present invention.

FIG. 5 is a circuit diagram showing a cooling refrigerant circuit of an air conditioner according to a conventional example.

[Explanation of symbols]

1 Compressor, 2 outdoor heat exchanger (condenser), 3 expansion valve, 4 indoor heat exchanger (evaporator), 5 high pressure switch, 6 high pressure sensor, 7 bypass solenoid valve, 8 outdoor heat exchanger Refrigerant inlet temperature sensor, 9 Refrigerant outlet temperature sensor of outdoor heat exchanger, 10 Outdoor unit suction temperature sensor, 1
1 outdoor air temperature sensor, 12 input device 13 arithmetic device, 14 storage device, 15 comparison device, 16 control unit,
17 Notification device.

Claims (1)

[Claims] An inlet temperature sensor and an outlet temperature sensor for detecting a refrigerant inlet temperature and a refrigerant outlet temperature of an outdoor heat exchanger of an air conditioner, respectively, and an inlet air temperature and an outlet air temperature of the outdoor heat exchanger, respectively. An outdoor unit intake air temperature sensor and an outdoor unit outlet air temperature sensor; a high pressure sensor for detecting a high pressure of a refrigerant circuit of an air conditioner; and a dirt detection for detecting dirt on a heat exchanger based on a detection value of these sensors. Means, and a notifying means for notifying dirt based on an output from the dirt detecting means. The dirt detecting means inputs a detection value of each of the sensors at regular time intervals, and detects dirt on the heat exchanger. Calculate the heat transmittance as a degree, accumulate the detected value of each sensor and the calculated heat transmittance, calculate a reference value of the degree of contamination of the heat exchanger based on the accumulated data, A heat exchanger contamination detection system for an air conditioner, comprising: comparing the heat transmittance with the determination reference value; and operating the notification means when the heat transmittance is lower than the determination reference value.