JPS62261845A - Defrosting controller for air-conditioning machine - Google Patents

Abstract

PURPOSE:To provide a defrosting controller capable of ensuring the operation thereof by a method wherein defrosting operation is controlled by a set temperature memorizing means, which stores a set temperature switched in accordance with the frequency of an electric source, and the difference of temperatures detected by two sets of temperature detecting means. CONSTITUTION:The capacity of a compressor 1 is different with frequency of an electric source 50Hz or 60Hz while the pressure and the delivery temperature of an outdoor heat exchanger 5 upon frosting are different in case the frequency of the electric source is different. The inlet pipeline temperature (t) of an indoor heat exchanger 3 is also different generally under 50Hz or 60Hz, therefore, the judgement of defrosting is effected by switching the set pipeline temperature (t1) under 50Hz or 60Hz. The inlet pipeline temperature (t1) of the indoor heat exchanger 3 is the temperature of refrigerant gas in an overheating area, therefore, it is hardly affected by the flow amount of a fan 7 while the central part pipeline temperature (t2) of the heat exchanger 3 detects a condensing temperature, therefore, it is stable accordingly, the judgement of defrosting operation may be effected properly under 50Hz or 60Hz by measuring a temperature difference (t1-t2).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a defrosting control device for a separate heat pump air conditioner, and particularly to a defrosting control device for detecting frost on an outdoor heat exchanger indoors. This relates to an air conditioner.

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 such a conventional configuration, the difference between the corrected temperature Tc of the indoor heat exchanger and the indoor temperature Ta (Tc-Ta) is larger than its maximum value (Tc-Ta)max. A defrosting signal is obtained when the temperature drops by a certain value, but the corrected temperature Tc of the indoor heat exchanger is a corrected value up to the minimum set air volume, and the air conditioner is not used indoors. When used, the filter installed in front of the indoor heat exchanger is full of dust, etc., and the air volume is usually lower than the minimum setting of the air conditioner. The difference (Tc - Ta) is its maximum value (Tc Ta ) ma
xjJ) may not decrease to a certain value, and there is a practical problem that defrosting operation is not performed even though the outdoor heat exchanger is frosted.

Also, depending on the power frequency, the compression function differs between 50Hz and 60 ratio, and generally speaking, 60an has higher pressure than 90Hz.
, even at the same indoor heat exchanger temperature, 501 and 601
In -1Z, the frosting state of the outdoor heat exchanger was different9, and accurate defrosting judgment could not be made.

As described above, the conventional technology has problems, and improvements are required.

In view of the above-mentioned conventional problems, the present invention provides a defrosting control device that can ensure reliable operation without sacrificing the advantages of the conventional technology.

Means for Solving the Problems In order to solve the above problems, the present invention provides a control device that controls the refrigeration cycle from the heating cycle to the defrosting cycle as shown in FIG. a time measurement means for measuring the time since 1999, a set time storage means for storing a preset time, and a match between the time detected by the time measurement means and the time set in the set time storage means. a first temperature detection means for detecting the temperature of a pipe connected to the refrigerant inlet side (during heating operation) of the indoor heat exchanger, and a first temperature detection means for detecting and outputting the temperature of the indoor heat exchanger. a second temperature detection means for detecting the temperature of the piping connected to the central part of the system; a set temperature storage means for storing a certain set temperature value for switching the heating cycle to the defrosting cycle; and a set temperature storage means for inputting the power frequency. 60f-[z clock input means and 50/80 for determining 50 and 60)
1z discriminating means, a set temperature switching means for switching a set temperature value of the set temperature storage means according to an output signal from the discriminating means, and a temperature detected by the first temperature detecting means and a second temperature detecting means. a second comparing means for detecting and outputting a difference between the detected temperature and the set temperature that is lower than a certain set temperature stored in the set temperature storage means; a set time elapsed signal from the first comparing means; determining means for determining switching from the heating cycle to the defrosting cycle based on a differential temperature value decrease signal from the comparing means; and a selection output for controlling the refrigeration cycle from heating operation to defrosting operation in accordance with the output of the determining means. It is composed of means.

Effect: With this configuration, heating operation is ensured until a predetermined time has elapsed from the start of heating operation, and after the elapse of the predetermined time, a set temperature storage means that stores a set temperature value that changes according to the N source frequency; The defrosting operation is controlled based on the difference in temperature detected by the two temperature detection means.

Embodiment One embodiment of the present invention will be described below with reference to FIGS. 2 to 5. FIG. 2 is a refrigeration cycle diagram showing an embodiment of the present invention. In the same figure, the refrigeration cycle includes compressor 1
．． Four-way switching valve 2, indoor heat exchanger 3, pressure reducer 4. It is constructed by sequentially connecting outdoor heat exchangers 5.

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 also a pipe temperature detection element υ.

It is attached to the piping in the center of the indoor heat exchanger to detect the refrigerant temperature in 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. Further, the compressor 1, the four-way switching valve 2. Pressure reducer4.
The outdoor heat exchanger 6 and the outdoor blower 8 constitute an outdoor unit A. In addition, the indoor heat exchanger 3 and the indoor blower 7. Furthermore, pipe temperature detection elements 6 and 6',
A microcomputer (hereinafter abbreviated as microcomputer) that is programmed with timer functions, temperature control functions, etc.
An operation control section (not shown) having an operation control section (not shown) is provided in the indoor unit B. Here, the pipe temperature detection element 6 is attached at a location away from the ventilation circuit where it is not affected by the air blowing from the indoor blower 7.

Alternatively, it may be near indoor unit)B.

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

In the figure, a voltage supplied from an AC power supply 18 is stepped down by a transformer 19, converted into full-wave rectification by a diode bridge 20, and the waveform of the full-wave rectification is converted into a clock signal by an inverter IC 21, which is input to the microcomputer 9. This signal causes the microcomputer 9 to

A 50760Hz discrimination means discriminates whether it is 50 Hz or 60 Hz. Here, if it is 60, Hi is output from the Pl port of the microcomputer 9, the reference voltage generated by the voltage division of the resistor 14.15 is raised, and the set temperature value is increased.

The microcomputer 9 also includes a storage unit 10 that stores a time-safe circuit for determining operating time, and a drive signal generator that generates an appropriate output signal from an AND circuit between the time-safe circuit stored in the storage unit 10 and an input value. There is a 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 temperature detection means;
An arithmetic processing unit 16 that processes signals from a heat exchanger temperature detection element 6' (for example, a piping thermistor or a thermocouple element) and a resistor 13' whose resistance value can be changed as necessary. Also connected are resistors 14, 15, and 17 whose resistance values can be changed as necessary. Furthermore, on the output side, there are a relay Rj that drives a four-way switching valve coil, which is a driving means, through switching transistors TR1 to TR4, a relay R2 that drives an indoor blower 7, and a relay R3 that drives an outdoor blower 8. Relay R4 that drives 1 is connected.

Here, comparing the configuration of FIG. 3 with the first configuration, the pipe temperature detection element 6 and the resistor 13 are replaced by the heat exchanger temperature detection element 6' and the resistor 13' in the first temperature detection means of FIG.
is the second temperature detection means, the comparator 12 and the arithmetic processing section 16 are the second comparison means in FIG.
The signals generated by the resistors 17 and 17 are the signals of the set temperature storage means shown in FIG.
The output signal from the port is sent to the set temperature switching means 507.
The clock signal generation circuit 22 is 50760 in FIG.
The microcomputer 9, which includes a storage section 10 as a clock input means, has a 50/60Hz discrimination means and a set time storage means 1 shown in FIG.
The time measurement means 1 corresponds to the judgment means 1 selection output means, and in particular, the drive signal generation means 11 corresponds to the judgment means 1 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 polytropic index is n (where 1
Given the relationship <n<K, where is the adiabatic compression index), the discharge refrigerant temperature Td is expressed by the following equation.

Td=Ts・(upper limit) n g Therefore, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature T8 is high, and the discharge refrigerant temperature Td is also high.

As the outside air drops and frost grows, the suction refrigerant temperature Ts decreases, and the discharge refrigerant temperature Td also decreases. The pipe temperature detection element 6 in the present invention is installed at the inlet pipe of the indoor heat exchanger 3, and detects the temperature of the part through which the superheated refrigerant gas discharged from the compressor 1 and having a very high temperature and high pressure flows. is a temperature lower than that of the discharged gas by a predetermined temperature due to heat loss in internal and external connecting pipes, etc. Further, the heat exchanger temperature detection element 6' is provided almost at the center of the indoor heat exchanger 3, and is a part where the high temperature and high pressure refrigerant gas discharged from the compressor 1 flows. This is the part where the temperature changes from a gas-liquid two-phase state to a liquid phase, but the temperature is considered to be approximately constant and is generally referred to as the condensation temperature. Also, what is the relationship between the temperature of the heat exchanger 30 inlet pipe and the condensation temperature?

When the refrigerant gas discharged from the compressor 1 flows into the heat exchanger 3 in a gas state with less superheated region, the temperature difference therebetween becomes smaller. Therefore, as shown in FIG. 4, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature Ts of the compressor 1,
The inlet pipe temperature t1 of the indoor heat exchanger 3 and the pipe temperature t2 at the center of the heat exchanger 3 are both high and gradually decrease as frosting progresses, reaching a frosting state that significantly reduces the heating capacity. and the inlet pipe temperature t1 of the indoor heat exchanger 3
At the same time, the central piping temperature t2 of the heat exchanger 3 also decreases, and the difference disappears, and the two become almost equal. That is, if the difference temperature t between the inlet pipe temperature t1 and the center pipe temperature t2 becomes less than the set pipe temperature t3, the heating capacity decreases and frost formation has progressed, so it is necessary to defrost. Also.

Depending on the power supply frequency, at 50 Hz and 60 Hz.

When the capacity of the compressor 1 is different and the outdoor heat exchanger 5 is frosted. High pressure and discharge temperature are different. That is, in 50- and 60-an, the inlet pipe temperature t of the indoor heat exchanger 3 is generally
The setting pipe temperature t1 is also switched between soh and 60 Hz to make a defrosting determination. In this way, the indoor heat exchanger 30 inlet pipe temperature t1 is the temperature of the refrigerant gas in the superheated region, so 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 the condensing temperature. is detected, so it is stable, and by measuring the temperature difference t1-t2, it is possible to accurately determine defrosting operation at both 950 Hz and 60 Hz.

Based on the above explanation, the control circuit shown in FIG. 3 controls the contents of the flowchart shown in FIG.

That is, in step 1 of Fig. 5, the power supply frequency is 60
It is determined whether it is a hermitage or not, and in step 2, if the frequency is 60Hz, the P1 port is set to Hi, and if the frequency is 50Hz, the Pl port is opened. Specifically, 50/60 in Figure 3
The signal from the 8Z clock generation circuit is discriminated by the 50760Hz discriminating means in the microcomputer 9, and if the Pl port on the output side of the microcomputer 9 is eO output, it is set to Hi, and the reference voltage created by the voltage division of the resistor 14.15 is raised. The set pipe temperature t3 is changed by 50/60Hz.

After that, heating operation is started in step 3.

The microcomputer 9 counts a timer count for a predetermined time T (step 4). This timer count set is for ensuring heating operation for 7 hours (for example, 1 hour) from the start of heating operation, and one means is to continue heating for 1, for example, 7 hours.

And once the timer count is set, step 5
It is determined that 7 hours have passed. Heating operation continues until 7 hours have passed.

After 7 hours have elapsed, the process moves to step 6.

The pipe temperature t1 is read by the pipe temperature detection element 6. Next, the process moves to step 7, where the heat exchanger temperature t2 is read by the heat exchanger temperature detection element 6'.
Moving on to step 8, the pipe temperature t1 and the heat exchanger temperature t2
It is determined whether the difference in temperature is lower than the set temperature t3. Specifically, the comparator 12 in FIG. 3 makes the determination.

When the conditions of step 8 are satisfied, the process moves to step 9 and defrosting operation is started. That is, the transistors TR1, TR2, TR3, and TR4 shown in FIG. 3 each operate to switch the four-way switching valve 2.

If necessary, the indoor blower 7 and the outdoor blower 8 are stopped for a certain period of time before that. Then, defrost is performed in the cooling cycle. The content of this defrosting operation is well known, so
Detailed explanation will be omitted. Further, the restoration of the heating operation can be carried out by any suitable means as is well known in the art.

Note that in Embodiment 3, the defrosting operation was 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 the refrigerant that has been stored separately is allowed to flow into the outdoor heat exchanger, or a configuration in which frost is melted using a separate 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 overmature region is detected at the indoor heat exchanger inlet piping, and the refrigerant condensation temperature in the gas-liquid two-phase region is detected indoors. Detects the temperature at the center of the inner heat exchanger, determines the temperature difference, and enables accurate defrosting operation with two temperature detection points.The configuration is very simple, and the refrigerant performs heating operation. Whether or not there is sufficient heat can be determined based on the temperature difference between the inlet side and the center of the indoor heat exchanger, and the set temperature can be changed at 50Hz and 80L, so even if the power supply frequency is different. Defrosting can be performed by reliably determining the presence or absence of actual heating capacity.

In other words, the present invention has the advantage that there is no difference in the temperature of the refrigerant between the inlet part and the center part of the heat exchanger when frost has completely formed (the inlet refrigerant temperature is higher than the refrigerant temperature in the center part when no frost has formed). 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. In addition, since the present invention does not detect frost formation until a certain period of time has passed from the start of heating,
During this period, heating capacity is ensured and comfort is not compromised.

[Brief explanation of drawings]

Fig. 1 is a block diagram expressing the defrosting control device of the present invention as a function realizing means, Fig. 2 is a refrigeration cycle 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. Figure 4 shows the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger, the temperature of the refrigerant in the center of the indoor heat exchanger, and the temperature of the refrigerant sucked into the compressor in the defrost control device. Characteristic diagram showing. FIG. 5 is a flowchart showing the operation details of the defrosting control device. 1... Compressor, 2... Four-way switching valve, 3
...Outdoor heat exchanger, S...Outdoor heat exchanger, 6...Piping temperature detection element, 6'...
...Temperature of the central piping of the heat exchanger. 9...Microcomputer, 10...
・Memory section. 11... Drive signal generating means, 12...
Comparator, 13, 13', 14, 15, 17...
···resistance. 22...5 o/s OHZ clock signal generation circuit, A...outdoor unit, B...indoor unit. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 1 - 11 pressure 11 micro 2...-Shoto central valve 3--Kohei air axis 4- Judgment pressure mixture A...-Outdoor unit B-m-Indoor unit 6--Yodo tube temperature Force 1 output element 6'--Heat exchanger Detection quantum 9--Micro repeater Fig. 3 tt--N dynamic signal generator 73, 73' 7475.17--Resistance #) −−°Scaling processing unit jI □ Figure 5

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 time measuring means for measuring the time from the start of heating operation of the compressor, a set time storage means for storing a preset time, and a time detected by the time measuring means. a first comparing means for detecting and outputting a coincidence of times set in the set time storage means; and a first comparing means for detecting a temperature of a pipe connected to a refrigerant inlet side of the indoor heat exchanger during heating operation. a temperature detection means, a second temperature detection means for detecting the temperature of the piping connected to the central portion of the indoor heat exchanger, and a set temperature memory storing a certain set temperature value for switching the heating cycle to the defrosting cycle. means and
50/60Hz clock input means for inputting the power supply frequency; 50/60Hz discrimination means for discriminating between 50Hz and 60Hz; and set temperature switching means for switching the set temperature value of the set temperature storage means based on an output signal from the discrimination means. , a second temperature detection means for detecting and outputting that the difference between the temperature detected by the first temperature detection means and the temperature detected by the second temperature detection means is lower than a certain set temperature stored in the set temperature storage means; a comparison means, a determination means for determining switching from a heating cycle to a defrosting cycle based on a set time elapsed signal from the first comparison means and a temperature difference value decrease signal from the second comparison means, and the determination means A defrosting control device for an air conditioner, comprising a selection output means for controlling the refrigeration cycle from heating operation to defrosting operation according to the output of the air conditioner.