JPS63189731A - Air conditioner defrosting control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a defrosting control device for a separate heat pump type air conditioner.

Conventional technology Conventional air conditioners detect frost on the outdoor heat exchanger based on both indoor heat exchanger temperature changes and indoor temperature changes, and control heating and defrosting operations. A technology has been developed to do so.

Problems to be Solved by the Invention However, such a conventional configuration requires a plurality of temperature detection elements, which naturally causes the problem of complicating the circuit.

Moreover, since this configuration detects the temperature of the gas-liquid mixed refrigerant flowing through the heat exchanger, the temperature change between frost and non-frost is small, and frost formation must be determined within a minute range. However, there is a problem that the detection accuracy is unstable.

In addition, in recent years, control devices are often configured by using microcomputers to perform complex signal processing, but the fact that there are many input signal sources (temperature detection elements) as in conventional technology makes it difficult to create programs. This is a source of harmful effects, and there are limits to the simplification of the program. Furthermore, there is a problem in that the temperature of the indoor heat exchanger is also affected by the amount of indoor air circulating based on the operation of the indoor blower.For example, if the amount of indoor air circulating to the indoor heat exchanger is small, the indoor heat exchange The temperature of the outdoor heat exchanger increases, and this causes an inconvenience in that the defrosting operation is not started even though it is necessary to perform a defrosting operation that penetrates the outdoor heat exchanger.

Furthermore, the rotational speed of the compressor differs due to the power frequency difference of 50 Hz/60 Hz, which causes a difference in the capacity of the refrigeration cycle and changes the temperature of the indoor heat exchanger. For example, in the case of 60Hz, the rotation speed of the compressor is higher and the capacity of the refrigeration cycle is greater than in the case of 50Hz, so the temperature of the indoor heat exchanger rises, and therefore, defrosting operation is required for the outdoor heat exchanger. There was a problem in that the defrosting operation did not start regardless of the condition.

The present invention solves the above-mentioned conventional problems.

It is an object of the present invention to provide a defrosting control device that enables malfunction-free defrosting operation and has a simplified configuration 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 time from the start, a first set time storage means for storing a preset time, and a time detected by the first time measuring means and the first time. a first comparison means for detecting and outputting the coincidence of the times set in the set time storage means; a temperature detection means for detecting the temperature of the pipe connected to the refrigerant inlet side of the indoor heat exchanger during heating operation; a set temperature storage means that stores a boundary value temperature for switching the cycle to a defrosting cycle; and a second temperature storage means that measures the time at which the temperature detected by the temperature detection means falls below the boundary value temperature stored in the set temperature storage means. a time measurement means; a second set time storage means storing a preset time; and a match between the time detected by the second time measurement means and the time set in the second set time storage means. a second comparison means for detecting and outputting the power supply frequency, a power supply frequency input means for inputting the power supply frequency, and a power supply frequency input means for inputting the power supply frequency;
50,760 Hz determining means for determining whether the frequency is 50,760 Hz or 60 Hz; an air volume switching means for switching the air volume;
a set temperature switching means for switching the boundary value temperature of the set temperature storage means based on the output of the 0/60 Hz determination means, and a temperature detected by the temperature detection means that is lower than the boundary value temperature stored by the set temperature storage means. a third comparison means for detecting and outputting a detection result, and a third comparison means for detecting whether or not the compressor is in operation for a predetermined time after the first set time elapses; compressor operation detection means for detecting that the compressor is being operated when a reduction signal is output; a set time elapsed signal from the first and second comparison means; and a boundary value reduction from the third comparison means. a determining means for determining switching from a heating cycle to a defrosting cycle based on the signal and a compressor operation detection signal by the compressor operation detecting means; and a determining means for determining switching from a heating cycle to a defrosting cycle based on the signal and a compressor operation detection signal by the compressor operation detecting means; and selection output means for controlling.

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, the compressor operation detection means detects whether the compressor is in operation, and further changes the air volume and power frequency. After a certain period of time has elapsed since the boundary value temperature has been lowered, when this boundary value temperature decrease signal is output, and the compressor operation detection signal is being output, the selection output means will cause the refrigeration cycle to change. Switch control from heating operation to defrosting operation.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 is a refrigeration cycle diagram showing one embodiment of the present invention. In FIG. 2, the refrigeration cycle consists of compressor 1. Four-way switching valve 2, indoor heat exchanger 3. It is constructed by sequentially connecting a pressure reducer 4 and an outdoor heat exchanger 5. 6 is a pipe temperature detection element, which detects the temperature of the indoor heat exchanger 3 during heating.
It is attached to the pipe on the refrigerant inlet side of the condenser. In this case, during cooling operation, the refrigerant flows in the direction of the solid arrow in FIG. 2, and during heating operation, the four-way switching valve 2 switches, so that the refrigerant flows in the direction of the broken arrow in FIG. 2.

Furthermore, the compressor 1. Four-way switching valve2. The pressure reducer 4, the outdoor heat exchanger 5, and the outdoor fan 8 are provided in the outdoor unit A, and the indoor heat exchanger 3 and the indoor fan 7.
An operation control section (C in FIG. 3) having a microcomputer programmed with a pipe temperature detection element 6, a timer function, a temperature adjustment function, etc. is provided in the indoor unit B. Here, the pipe temperature detection element 6 is installed at a location away from the air circuit so as not to be affected by the air blown by the indoor air blower 7. Alternatively, the location may be near the indoor unit B.

FIG. 3 is a diagram showing the operation control section C and the control operation section. The operation control unit C steps down the voltage supplied from the AC power supply 11 with the transformer 12, converts it into full-wave rectification with the diode bridge 14 in the DC power supply generation unit 13, and converts the voltage supplied from the AC power supply 11 into full-wave rectification with the
Cl3 is used to create the DC power supply that operates the microcomputer 16 (hereinafter referred to as microcomputer). Microcomputer 16
In this case, the reset circuit 17 is connected to the P0 port, and the transmitting circuit I8 is connected to the P0 port.
are connected to ports p,, p, respectively. In addition, a scan signal is output from the p,, p, ports, and the air volume selector switch 19 and room temperature setting switch 20 of the control operation section are set to 0N10FF, and the P,, P4. Various scan signals enter the P port, and predetermined control is performed thereby. A signal is issued from the P11 boat to operate the relay that drives the compressor 1, and a signal is issued from the P12 port to operate the relay that drives the four-way switching valve 2.
A signal to operate a relay that drives the outdoor blower 8 is output from the Pl port, and a signal to operate a relay that drives the indoor blower 7 is output from the P□ to Pi6 ports. In addition, from the Pl, ~P2° ports, a signal is output for the D/A converter 22 to generate a reference voltage for detecting the room temperature by comparing it with the input signal from the suction sensor 21.
The output of a comparator 23 that compares the reference voltage with the input signal of the suction sensor 21 is input to the P1 port. The microcomputer 16 receives the input from the room temperature setting switch 2o in the control operation section, compares it with the input from the P21 port, and compares it with the input from the P21 port.
ON10FF control is performed. Air volume is Hi, Me, L
.

As the output port of p, , p24 changes to H
(High) signal is outputted, and the set temperature storage resistors 28 and 2 of the set temperature storage means 27 are set by the set temperature switching resistors 24 to 26.
The reference voltage is switched according to the boundary value temperature stored in step 9. The reference voltage and the signal from the pipe temperature detection element 6 are compared by a comparator 30 and input to P2@.

The power supply frequency signal is converted from the DC power generation section 13 into a clock signal by the inverter 31, and is input to the P1o port. Upon receiving the clock signal, if the 50760Hz determination means inside the microcomputer 16 determines that the frequency is 60Hz, P2. H (high) output is output from the port,
The set temperature switching resistor 32 switches the set value of the set temperature storage means 27 as the boundary value temperature.

Here, comparing the configuration of FIG. 3 with the configuration of FIG. 1, the pipe temperature detection element 6 includes a comparator 3 as a temperature detection means
0 is used as the third comparison means, resistors 28.29 are used as the set temperature storage means, the air volume changeover switch 19 on the control operation section is used as the air volume selection means, the inverter 31 is used as the power frequency input means, and the resistors 24 to 26.32 are used as the power supply frequency input means. correspond to set temperature switching means, and the microcomputer 16 excludes first and second set time storage means, first and second time measurement means, 50/60Hz determination means, first, second, and comparator 30. This corresponds to third comparison means, compressor operation detection means, 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, and 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 < n < k, where is an adiabatic compression index), then the discharge refrigerant temperature Td is expressed by the following equation.

Therefore, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature Ts is high and each discharge refrigerant temperature Td is also high, but as the outside air drops and the frost grows, the suction refrigerant temperature Ts decreases and the discharge The refrigerant temperature Td also decreases.

The pipe temperature detection element 6 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. Compared to this, the temperature is lowered by a predetermined temperature due to heat loss in internal and external connecting pipes, etc. Therefore, as shown in FIG. 4, when the outdoor heat exchanger 5 is not frosted, both the suction refrigerant temperature Ts of the compressor 1 and the inlet pipe temperature t of the indoor heat exchanger 3 are high, and frosting progresses. The temperature t of the inlet pipe of the indoor heat exchanger 3 gradually decreases, and when frost formation occurs which significantly reduces the heating capacity, the temperature t of the inlet pipe of the indoor heat exchanger 3 decreases extremely. That is, if the inlet pipe temperature t becomes lower than the set pipe temperature t1 (60 Hz air volume Lo), the heating capacity decreases, and since frost formation has progressed, it is necessary to defrost.

In addition, since this inlet pipe temperature is slightly affected by the air volume, as shown in Figure 4, the air volume varies.

By changing the set pipe temperature to jzt jaw tx (in the case of 60 Hz) with the air flow rate Me (weak wind), the air flow rate M e (medium wind), and the air flow rate Hi (strong wind), frost formation can be detected more accurately. Furthermore, the rotation speed of the compressor 1 is set to a power supply frequency of 50Hz.
Since the value is almost proportional to 60 Hz, the high pressure of the refrigeration cycle is high at 60 Hz. Therefore, the inlet pipe temperature of the indoor heat exchanger shown in Fig. 4 is, if the solid line section t is 60Hz, the broken line section t is 50Hz, and if the start of defrosting is fixed only at tx (air volume Lo), it is 50Hz.
In this case, defrosting begins before there is much frost and heating efficiency deteriorates. Therefore, in the case of 50 Hz, the optimum defrosting operation is ensured by setting the defrosting start temperature of the inlet pipe temperature of the indoor heat exchanger to t,/.

Based on the above explanation, the control circuit shown in FIG. 3 controls the contents of the flowchart shown in FIG. 7.

In other words, normal heating operation is started in step 1 of Fig. 5, and when the power frequency is input in step 2, it is determined in step 3 whether it is 50Hz or 60Hz, and if it is 60H2, P
2. Set the port output to H (high) to increase the piping temperature set value (step 4). Then, the microcomputer 16 counts the timer count for a predetermined time T1 (step (
5)). The first timer counter is set to ensure heating operation for T1 hours (for example, 1 hour) from the start of heating operation. For example, one means is to forcibly continue heating for T hours.

And when the first timer count is set.

In step 6, it is determined whether the T1 time has elapsed. The heating operation continues as shown in FIG. 5 until 10 hours have elapsed.

When the time T1 has elapsed, the process moves to step 7, where a second timer counter is set, and the process moves to step 8, where it is determined in the microcomputer 16 whether or not the compressor 1 is operating. If the compressor 1 is not in operation, the process returns to step 7 and the second timer counter is set again.

Next, when the conditions of step 8 are satisfied, it is determined in step 9 that 12 hours (for example, about 4 minutes) have passed. That is, in steps 7 to 9, the compressor 1
It is confirmed whether or not it is being operated continuously.

After the compressor 1 has been continuously operated for 12 hours with the second timer counter set, the process moves to step 10, where the third timer counter is set. As shown in FIG.
The time T3 (for example, 1 minute) during which the value is continuously lower than ta)
It is provided to detect the pipe temperature t lower than the actual temperature due to noise, for example, and to prevent the defrosting operation from being started by mistake.

When this third timer counter is set, the air volume is determined primarily. If the air volume is Lll (weak wind), set the output of the P22 port to H (high) in step 11.12).
If the air volume is Me (medium wind), P2. Set the port output to H(
Step 13.14), otherwise (Air volume H)
i), set the P24 port output to H (high) (step 15), and in this way resistor 28.
The set piping temperature determined by the voltage consisting of the partial pressure of 29 is set using resistors 24 to 26.32 at a power frequency of 50 Hz and 6
It is possible to change it by changing the 0 Hz difference or the air volume.

Once the set pipe temperature is set, the pipe temperature t is read by the pipe temperature detection element 6 in step 16, and the process moves to step 17, where it is again determined whether the compressor 1 is operating. And the inlet pipe temperature t7! lt
, if it is lower than the set piping temperature tx corresponding to each power supply frequency and each air volume (step 18), comparator 3
H (high) output is output from 0. When the conditions of step 18 are satisfied, it is determined in step 19 whether the time T1 has elapsed. As shown in FIG. 6, the heating operation is continued until the time T1 has elapsed, and if the inlet pipe temperature t is higher than the set pipe temperature tx before the time T1 has elapsed, the process returns to step 10 and the third timer is activated. Counter is reset.

Then, when the conditions of step 19 are satisfied, step 20
The defrosting operation starts.

That is, the P11 to P0 port outputs are changed, the four-way switching valve 2 is switched, and if necessary, the compressor 1 is stopped for a certain period of time, and the indoor blower 7 and the outdoor blower 8 are stopped.

Defrost is then performed in the cooling cycle. Since the content of this defrosting operation is conventionally well known, 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.

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 refrigerant that has been separately stored 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, the temperature of the refrigerant gas in the superheated region is detected at the indoor heat exchanger inlet pipe.

Corrections are made using the power supply frequency and room air volume, and accurate defrosting operation can be performed with a single temperature detection point, making the configuration extremely simple, and the refrigerant has sufficient heat for heating. Since it can be determined on the inlet side of the indoor heat exchanger whether there is actual heating capacity or not, defrosting can be performed by reliably determining the presence or absence of actual heating capacity.

More specifically, in the present invention, there is no difference in the temperature of the refrigerant at the inlet part and the middle part of the heat exchanger when frost has completely formed, and when no frost has formed, the inlet refrigerant temperature is higher than the refrigerant temperature at the middle part. By focusing on the refrigerant temperature on the inlet side and detecting the refrigerant temperature at a point that is significantly higher than the refrigerant temperature, the temperature change from non-frost to frost can be made large, and heating capacity close to the limit can be brought out by detecting the temperature at one point. be able to.

Furthermore, since the present invention does not detect frost formation until a certain period of time has elapsed from the start of heating, the heating capacity is ensured for that certain period of time, and comfort is not impaired.

In addition, during heating operation, the present invention does not detect frost formation until a certain period of time has passed after the compressor restarts after the compressor is temporarily stopped. The temperature of the heat exchanger piping is detected so that defrosting operation will not be started by mistake even if no frost has formed.

Furthermore, since the defrosting operation is not started unless the pipe temperature of the indoor heat exchanger continuously falls below the set temperature,
Reliable frost detection is possible, such as preventing false start of defrosting operation due to pipe temperature being detected as lower than the actual temperature due to noise etc.

This has the effect of performing highly reliable defrosting control without malfunction.

[Brief explanation of the drawing]

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. A circuit diagram of the defrosting control device, Fig. 4 is a characteristic diagram showing the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger and the temperature of the refrigerant sucked into the compressor in the defrosting control device, and Fig. 5 is a characteristic diagram showing the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger and the temperature of the refrigerant sucked into the compressor in the defrosting control device. T1 is a diagram showing the relationship between the operating time and piping temperature, which indicates that the heating operation is to be continued, and FIG. FIG. 7 is a flowchart showing the operation of the defrosting control device. DESCRIPTION OF SYMBOLS 1... Compressor, 2... Four-way switching valve, 3... Indoor heat exchanger, 5... Outdoor heat exchanger, 6... Piping temperature detection element, 16... Microcomputer , 19...
・Air volume selection switch, 20...Room temperature setting switch, 2
3... Comparator, 24-26.32... Set temperature switching resistor, 28.29... Set temperature memory resistor,
30...Comparator. Agent Yoshihiro Morimoto Figure 1 Figure 2 R /-, - 10,000-100-1Eμi (Rtsutribute R exchange I4shi store ito 4--; Nail pressure device! Sea-X 91411'19F! Exchange jD SΔ-・
O-tube j end] Pickled: B-boiled chia -1rE Kadan Sakura/-11 room evening VtLA person f~ 1: Amount 1: Hourly opening 5th = Fig.

Claims (1)

[Claims] 1. A refrigeration cycle equipped with a compressor, an indoor heat exchanger, a pressure reducer, 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 further removed from the heating cycle. a control device for switching to a frost cycle; the control device includes a first time measuring means for measuring time from the start of heating operation of the compressor; and a first setting for storing a preset time. a time storage means; a first comparison means for detecting and outputting a match between the time detected by the first time measurement means and the time set in the first set time storage means; temperature detection means for detecting the temperature of piping connected to the refrigerant inlet side of the heat exchanger; set temperature storage means for storing a boundary value temperature for switching the heating cycle to the defrosting cycle; and the temperature detected by the temperature detection means. a second time measuring means for measuring the time during which the temperature has decreased below the boundary value temperature stored in the set temperature storage means; a second set time storage means for storing a preset time; a second comparing means for detecting and outputting a match between the time detected by the time measuring means and the time set in the second set time storage means; a power frequency inputting means for inputting the power frequency; 50/60 Hz determination means for determining whether the frequency is 50 Hz or 60 Hz, air volume switching means for switching the air volume, and set temperature switching means for switching the boundary value temperature of the set temperature storage means based on each air volume and the output of the 50/60 Hz determination means. , third comparison means for detecting and outputting that the temperature detected by the temperature detection means has fallen below the boundary value temperature stored in the set temperature storage means; Compressor operation detection means for detecting whether the compressor is in operation or detecting that the compressor is being operated when the third comparison means outputs the boundary value temperature drop signal; From the heating cycle by the first and second set time elapsed signals from the first and second comparing means, the boundary value decrease signal from the third comparing means, and the compressor operation detection signal from the compressor operation detecting means. A defrosting control device for an air conditioner, comprising a determining means for determining switching to a defrosting cycle, and a selection output means for controlling the refrigeration cycle from heating operation to defrosting operation according to an output of the determining means.