JPS62210341A - Control device for defrosting of air-conditioning machine - Google Patents

Abstract

PURPOSE:To effect defrosting after deciding whether actual heating capacity exists or not surely by a method wherein a set temperature storing means, storing a boundary value temperature in accordance with an indoor airflow amount, is equipped to change the value of a set temperature difference in accordance with the amount of indoor airflow. CONSTITUTION:If the amount of indoor airflow is large, the sucking refrigerant temperature Ts of a compressor 1, the inlet pipeline temperature (t1) of an indoor side heat exchanger 3 and the temperature (t2) of a pipeline at the center of the heat exchanger 3 are reduced gradually when an outdoor heat exchanger 5 is not frosted yet, however, when the state of frosting, which reduces heating capacity remarkably, is achieved, the inlet pipeline temperature (t1) of the indoor side heat exchanger 3 is reduced extremely. When said respective temperature are shown by (t1'), (t2'), T's in the case the amount of indoor airflow is small, the values of (t1'), (t2') are higher than said respective values (t1), (t2) but the value of (t1')-(t2') is smaller than the value of (t1)-(t2). Therefore, the more proper decision of defrosting operation may be effected by changing the value of compared temperature difference in accordance with the amount of indoor airflow. At the same time, when the central pipeline temperature (t2) is reduced and a temperature difference (t1)-(t2) becomes lower than a set pipeline temperature (t), heating capacity is reduced and defrosting is needed. The decision of defrosting is effected by switching the set pipeline temperature (t1) to the degree of airflow amount of strong, medium and weak.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a static elimination control device for a separate heat pump type air conditioner, and in particular, it is capable of detecting frost on an outdoor heat exchanger indoors. It is related to air conditioners.

BACKGROUND ART Conventionally, as shown in Japanese Patent Publication No. 59-34255, the state of frost on an outdoor heat exchanger is detected based on both the temperature change of the indoor heat exchanger and the indoor temperature change. Technologies have been developed to control heating and defrosting operations.

Problems to be Solved by the Invention However, in this conventional configuration, the difference (Tc - Ta) between the corrected temperature Tc of the indoor heat exchanger and the indoor temperature Ta is a constant value that is smaller than the maximum value (Tc Ta) max. When the temperature drops, a defrosting signal is obtained, but the correction temperature Tc of the indoor heat exchanger is a correction value up to the minimum set air volume, and when the air conditioner 5 shallow is used in the room. case,
The filter installed in front of the indoor heat exchanger is often clogged with dust, etc., which causes the air volume to drop below the minimum setting of the air conditioner, and the difference between the correction temperature Tc and the indoor temperature Ta (
Tc-Ta) is its maximum value (Tc-Ta)max
There are cases where the temperature does not decrease to a certain value even though the outdoor heat exchanger is frosted, and there is a practical problem in that the defrosting operation is not performed even though the outdoor heat exchanger is frosted.

In addition, the air volume is higher in strong winds than in weak winds, and even at the same indoor heat exchanger temperature, the frosting conditions on the outdoor heat exchangers are different between 50an and 60den, making it difficult to make accurate defrost judgments. could not.

As described above, the conventional technology has at least one drawback, and improvements are required.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a control device that can ensure reliable operation without sacrificing the advantages of the prior art.

Means for Solving the Problems In order to solve the above problems, the present invention, as shown in FIG. a first time measuring means for measuring the time from
a first comparing means for detecting and outputting the coincidence of the time set in the set time elapsed signal; and a second time measuring means for measuring the time from the start of restarting the compressor after the temporary operation stop of the compressor. A second set time elapsed signal that stores a preset time, and a match between the time detected by the second time measuring means and the time set in the second set time elapsed signal is detected and output. a first temperature detection means that detects the temperature of a pipe connected to the refrigerant inlet side of the indoor heat exchanger during heating operation; a second temperature detection means for detecting the temperature of the piping, an air volume adjustment means for switching the indoor air volume and outputting a setting change as a set temperature elapsed signal, and a certain set temperature value for switching the heating cycle to the defrosting cycle. a set temperature elapsed signal that stores a certain set temperature value for switching the heating cycle to a defrosting cycle, a temperature detected by the first temperature detection means, and a temperature detected by the second temperature detection means. a third comparison means for detecting and outputting a difference in temperature from a certain set temperature stored in the set temperature elapsed signal;
determining means for determining switching from the heating cycle to the defrosting cycle based on the set time elapsed signal from the comparing means and the differential temperature value decrease signal from the third comparing means; It is composed of selection output means for controlling the cycle from heating operation to defrosting operation.

Effect: With this configuration, the set temperature elapsed signal that stores the boundary value temperature according to the indoor air volume, and also the value of the set temperature difference that is stored according to the indoor air volume in the present invention, can be changed, so that the change in the indoor air volume can be changed. Since the difference in temperature due to the difference in the degree of superheating can be compared, the frosting state can be detected more accurately.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 2 to 5. FIG. 2 is a refrigeration cycle diagram showing one embodiment of the present invention. In the same figure, the refrigeration cycle includes compressor 1
, a four-way valve 2, an indoor heat exchanger 3, a pressure reducer 4, and an outdoor heat exchanger 5 are connected in sequence.

Reference numeral 6 denotes a pipe temperature detection element, which is attached to a pipe that is on the refrigerant inlet side of the indoor heat exchanger 3 (condenser) during heating. Similarly, 6' is a pipe temperature detection element, which is attached to the pipe at the center of the indoor heat exchanger and detects the refrigerant temperature at the center of the heat exchanger.

In this case, during cooling operation, the refrigerant flows in the direction of the solid line arrow in the figure, and during heating operation, the four-way switching valve 2 is switched so that the refrigerant flows in the direction of the broken line arrow in the figure. Furthermore, the compressor 1, the four-way switching valve 2, the pressure reducer 4,
The outdoor heat exchanger 5 and the outdoor blower 8 constitute an outdoor unit A. In addition, the indoor heat exchanger 3 and the indoor blower 7, and the pipe temperature detection elements 6 and 6
', an operation control section (not shown) having a microcomputer (hereinafter abbreviated as microcomputer) programmed with a timer function, temperature control function, etc. is an indoor unit) B.
It is set in. Here, the pipe temperature detection element 6 is installed at a location away from the ventilation circuit where it is not affected by the air flow V of the indoor blower 7.

Alternatively, the location may be near indoor unit B.

FIG. 3 is a main circuit diagram of the operation control section.

In the same figure, the microcomputer 9 includes a memory section 10 that stores a time-seven-failure circuit for determining operating time, and an AND circuit between the time safe circuit stored in the memory section 10 and an input value to generate an appropriate output signal. There is a drive signal generating means 11. On the input side of the microcomputer 9, a comparator 12 is connected to a pipe temperature detection element 6 (for example, a pipe thermistor or a thermocouple element) as a temperature detection means, and a resistor 13 whose resistance value can be changed as necessary. 1, a heat exchanger temperature detection element 6' (for example, a piping thermistor or a thermocouple element, etc.), and an arithmetic processing unit 25 that processes signals from a resistor 13' whose resistance value can be changed as necessary. Switches F-14 and F-15 respond to this and resistors 16, 17 and 18 (resistance 16<17<I E3 ) connected to their respective terminals (resistance 26 whose resistance value can be changed)
is connected.

In addition, on the output side, switch transistors TR1 to TR
4, relay R1 that drives the four-way switching valve coil that is the drive means, relay R2 that drives the indoor blower 7, relay R3 that drives the outdoor blower 8, and relay R4 that drives the compressor 1 are read directly. .

Here, when comparing the configuration of FIG. 3 with the first configuration, the piping temperature detection element 6 and the resistor 13 correspond to the first temperature detection means in FIG. 13' corresponds to the second temperature detection means, and comparator 1
2 and the arithmetic processing section 20 correspond to the second comparing means in FIG. The microcomputer 9 corresponds to the set time elapsed signal, time measurement means, determination means, and selection output means in FIG. 1, and the drive signal generation means 11 corresponds to the determination means and selection output means.

Next, the operation from the start of heating operation to defrosting operation will be explained.

The discharge refrigerant temperature of the compressor 1 is Td, the suction refrigerant temperature of the compressor 1 is Ts, the discharge pressure of the compressor 1 is Pd, the suction pressure of the compressor 1 is Ps, and the po IJ I-rope index is n (however, 1 < n < K, where K is an adiabatic compression index), the discharge refrigerant temperature Td is expressed by the following formula. Therefore, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature Ts is high;
Furthermore, the discharge refrigerant temperature Td is also high. Then, as the outside air cools and the snow builds up, the suction refrigerant temperature Ts decreases, and the discharge refrigerant temperature Td also decreases. At the same time, the suction pressure Ps and the discharge pressure Pd also decrease. The pipe temperature detection element 6 in the present invention is
It is installed in the inlet pipe of the indoor heat exchanger 3 and detects the temperature of the part through which the high-temperature, high-pressure superheated refrigerant gas discharged from the compressor 1 flows; This is the temperature that has decreased by a predetermined temperature due to heat loss. Furthermore, the heat exchanger temperature detection element 6' is connected to the indoor heat exchanger 3.
This is the part where the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 flows, and it is the part where the discharged refrigerant gas changes from the gas phase to the gas-liquid two-phase state and then to the liquid phase. , whose temperature is considered to be approximately constant and is commonly referred to as the condensation temperature. The relationship between the temperature of the inlet pipe of the heat exchanger 3 and the condensation temperature is such that when the refrigerant gas discharged from the compressor 1 flows into the heat exchanger 3 in a gas state with a small superheated region, the temperature difference is It's getting less. Further, this temperature difference also changes depending on the indoor air volume; when the indoor air volume is large, the degree of superheating increases and the temperature difference becomes large, and when the indoor air volume is small, the temperature difference becomes small.

Therefore, as shown in FIG. 4, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature of the compressor 1 is Ts.

As the temperature progresses, the temperature gradually decreases, and when a frost condition occurs that significantly reduces the heating capacity, the temperature t1 of the inlet pipe of the indoor heat exchanger 3 becomes extremely low.

Furthermore, t'1+ ``2+''s in the same figure shows the inlet pipe temperature, center pipe temperature, and compressor suction temperature when the indoor air volume is small, and the broken line shows the behavior. As shown in the figure, the value of ``1+ t'2 is t'1+
j'2, but smaller than the temperature difference t1-t2. Therefore, the value of the temperature difference to be compared can be changed more accurately according to the indoor air volume. It is possible to make accurate defrosting operation decisions.

At the same time, the central piping temperature t2 of the heat exchanger 3 also decreases, the difference disappears, and the temperatures progress to almost the same state. That is, if the difference temperature t between the inlet pipe temperature a t 1 and the center pipe temperature t2 becomes less than the set pipe temperature, the heating capacity decreases and frost formation has progressed, so it is necessary to defrost.

Furthermore, the compressor's high pressure and discharge temperature are different in strong wind, medium wind, and weak wind. That is, the inlet pipe temperature t of the indoor heat exchanger 3 generally differs between strong winds, medium winds, and weak winds, and the defrosting determination is performed by changing the set pipe temperature t1 for strong winds, medium winds, and weak winds.

In this way, since the inlet pipe temperature t1 of the indoor heat exchanger 3 is the temperature of the refrigerant gas in the superheated region, it is not easily affected by the air volume of the blower 7, and the central pipe temperature t2 of the heat exchanger 3 is
Since it detects the condensing temperature, it is stable, and by measuring the temperature difference t1-t2, it is possible to make an accurate decision on defrosting operation, and it is possible to make accurate decisions about defrosting operation due to changes in the refrigeration cycle due to indoor air volume. The defrosting operation can be determined accordingly.

That is, in step 1 of FIG. 5, it is determined whether the air volume is strong, medium, or weak, and the air volume selector switch 14, 15 and the resistance values 16, 17, . 18.
The resistance value is changed (resistance 18<17<18) and the set temperature t3 is changed accordingly depending on the air flow rate: high, medium, or low. After that, when the heating operation is started as shown in step 4, the microcomputer 9 (step 3) sets the timer count to ensure the heating operation for T1 hours (for example, 1 hour) from the start of the heating operation. For example, one means is to continue heating for T1 hours.

And once the timer count is set, step 4
It is determined that the T1 time has passed. The heating operation is continued until the time T1 has elapsed.

When the time T1 has elapsed, the process moves to step 5, where a second timer counter is set, and the process moves to step 6, where it is determined in the microcomputer 9 whether or not the compressor 1 is operating. If no driving is performed (step 5)
(if not satisfied), the process returns to step 6 and the first timer counter is reset.

Next, when the condition of step 7 is satisfied, 1 is reached in step 8.
It is determined that two hours (for example, four minutes) have passed.

When the compressor 1 has been continuously operated for 12 hours, the process moves to step 11, where the pipe temperature detection element 6 reads the pipe temperature t1.

Next, the process moves to step 9, where the heat exchanger temperature t2 is read by the heat exchanger temperature detection element 6', and further, the process moves to step 10, where it is again determined whether or not the compressor 1 is operating.

Then, the process moves to step 11, and it is determined whether the temperature difference between the pipe temperature t1 and the heat exchanger temperature t2 is lower than the set temperature t. Specifically, the comparator 12 in FIG. 3 makes the determination.

Then, when the conditions of step 11 are satisfied, step 12
The defrosting operation starts. That is, the transistors TR1, TR2, TR3, and TR4 shown in FIG. 3 operate, respectively, to switch the four-way control valve 2, and if necessary, stop the operation for a certain period of time beforehand, thereby stopping the indoor blower 7 and the outdoor blower 8. Defrosting is then performed in the cooling cycle, and since the content of this defrosting operation is well known, detailed explanation will be omitted. Also, regarding the return of heating operation, as is well known,
This can be done by any appropriate means.

In this embodiment, the defrosting operation is performed by switching from the heating cycle to the cooling cycle.
For example, it goes without saying that a configuration may be adopted in which the heating cycle is maintained and a separately stored refrigerant is flowed to the outdoor heat exchanger, or a configuration in which the lightning is melted by a side heat source. Further, the compressor 1 may be operated continuously when switching to defrosting operation, and may be temporarily stopped before returning to heating operation.

Effects of the Invention As described above, according to the present invention, with the above configuration, the refrigerant gas temperature in the superheated region is detected at the indoor heat exchanger inlet piping, and the refrigerant condensation temperature in the gas-liquid two-phase region is detected in the indoor heat exchanger. By detecting the temperature difference in the center of the exchanger, it is possible to perform accurate defrosting operation with two temperature detection points. Whether or not there is sufficient heating capacity can be determined based on the temperature difference between the inlet side and the center of the indoor heat exchanger, and even if the indoor air volume setting is different, the set temperature can be changed, so the presence or absence of actual heating capacity can be determined. Defrosting can be performed based on reliable judgment.

In other words, the present invention is completely implemented; there is no difference in the temperature of the refrigerant where the frost is generated between the inlet part and the center part of the heat exchanger, and when there is no frost, the inlet refrigerant temperature is higher than the refrigerant temperature in the center part. By focusing on the point where the temperature is extremely high and detecting the refrigerant temperature on the inlet side and the refrigerant temperature in the center, it is possible to obtain a large temperature difference change from non-frost to frost, and it is possible to reach the limit by detecting the temperature at two points. It is possible to draw out similar heating capacity. Furthermore, since the present invention does not detect frost formation until a certain period of time has elapsed from the start of heating, heating capacity is ensured during that certain period of time, and comfort is not impaired.

In addition, during heating operation, after the compressor is temporarily stopped, frost formation is not detected until a certain period of time has elapsed since the restart of operation. The piping temperature is detected, and there is no possibility of accidentally starting the de1 operation even though there is no frost.

[Brief explanation of drawings]

Fig. 1 is a block diagram expressing the defrosting control device of the present invention using function realizing means, Fig. 2 is a refrigeration cycle diagram of an air conditioner showing an embodiment of the present invention, and Fig. 3 is a block diagram of the defrosting control device of the present invention. The circuit diagram of the defrosting control device, Figure 4, shows the relationship between the refrigerant temperature flowing into the indoor heat exchanger, the refrigerant temperature in the center of the indoor heat exchanger, and the compressor suction refrigerant temperature in the defrosting control device. The characteristic diagram and FIG. 5 are flowcharts showing the operation details of the defrosting control device. 1... Compressor, 2... Four-way switching valve, 3
...Indoor heat exchanger, 5...Outdoor heat exchanger, 6...Piping temperature detection element, 6'...
...Central piping temperature of heat exchanger, 9...Microcomputer, 10...Storage section, 11...
1. Dynamic signal generating means, 12.. Comparator, 16, 17, 18, 27.. Resistor, A.. Outdoor unit, B.. Indoor unit. . Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Diagram/- Pressure shallow 2 - Yomokiri chusuke 3 - 1 indoor unit order se η , vessel 4 - 1 pressure vessel 5 - 1 1 nitrogen outside tsuta exchange ironware A - m - outdoor unit B - 1 1 Emperor C unit 6---Trade f comrade friend chichichichichiko g'-1゛Mature interlacing device Mθ extraction element/3. IE', 17--Resistance I6- Operation heat 3! Part 4

Claims (1)

[Claims] A refrigeration cycle equipped with a compressor, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger is provided with cycle switching means for switching between a heating cycle and a defrosting cycle, and the cycle switching means is configured to switch between a heating cycle and a defrosting cycle. A control device for switching to a cycle is controlled by a first time measuring means for measuring time from the start of heating operation of the compressor, a first set time storage means for storing a preset time, and a first set time storage means for storing a preset time; a first comparing means for detecting and outputting a match between the time detected by the time measuring means and the time set in the first set time storage means; a second time measurement means for measuring time; a second set time storage means for storing a preset time; and a memory for the time detected by the second time measurement means and the second set time. a second comparison means for detecting and outputting a coincidence of times set in the means; and a first temperature detection means for detecting the temperature of a pipe connected to the refrigerant inlet side of the indoor heat exchanger during heating operation. , a second temperature detection means for detecting the temperature of the pipe connected to the central part of the indoor heat exchanger; a set temperature storage means for storing a certain set temperature value for switching the heating cycle to the defrosting cycle; a set temperature switching means for switching the boundary value temperature of the set temperature storage means based on an output signal from the discriminating means; a third comparison means for detecting and outputting that the difference between the temperature and the temperature detected by the second temperature detection means has fallen below a certain set temperature stored in the set temperature storage means; determining means for determining switching from the heating cycle to the defrosting cycle based on a set time elapsed signal from the comparing means and a differential temperature value decrease signal from the third comparing means; A defrosting control device for an air conditioner comprising selection output means for controlling from heating operation to defrosting operation.