JPS6315020A - Defrosting controller for air conditioner - Google Patents

Abstract

PURPOSE:To provide a defrosting controller which is simply constituted by detecting the temp. of the refrigerant gas in an overheated zone at the inlet piping of an indoor side heat exchanger and correcting the gas temp. by an indoor air quantity. CONSTITUTION:A piping temp. detecting element 6 is installed at the inlet piping of an indoor side heat exchanger 3 and a set piping temp. is able to be varied by the change of air quantity in using resistances 12-14. When the set piping temp. is settled, the read-in of piping temp. is performed by the element 6 and if the inlet piping temp. t is lower than the set piping temp. tx corresponding to each air quantity, Hi output is transmitted from a comparator 27 and space heating operation is continued until time T2 has elapsed and when the temp. t exceeds the set temp. tx before time T2 has elapsed, a secondary timer counter is reset to start defrosting operation. That is, port output P11-P16 is changed and a four-way change-over valve 2 is switched over and a compressor 1 is stopped for a specified time as required and an indoor blower 7 and an outdoor blower 8 are stopped. Then defrosting is achieved by a space cooling cycle.

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.

BACKGROUND ART Conventionally, as shown in Japanese Patent Publication No. 58-32296, 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, such a conventional configuration requires a plurality of temperature detection elements, and has the problem of complicating the eyes and circuitry. Furthermore, since this configuration detects the temperature of the gas-liquid mixed refrigerant while 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. 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 circulation 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 temperature of the indoor heat exchanger will rise accordingly, and therefore, even though defrosting operation is required for the outdoor heat exchanger, defrosting operation is not performed. This causes the inconvenience of not starting.

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

In view of the above-mentioned conventional problems, the present invention provides a defrosting control device that can be simplified in configuration without sacrificing the advantages of the prior art.

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 first time measuring means for measuring the time from , a first set time storage means for storing a preset time, and a time detected by the first time measuring means and the first setting. a first comparison means for detecting and outputting the coincidence of times set in the time storage means; a 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 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 when the temperature detected by the temperature detection means falls below the boundary value temperature stored in the set temperature storage means. a time measuring means, a second set time storage means storing a preset time, and a time detected by the second time measuring means and a time set in the second set time storage means. a second comparing means for detecting and outputting a match;
An air volume switching means for switching the air volume, a set temperature switching means for switching the set temperature according to each air volume, and detecting and outputting that the temperature detected by the temperature detection means has fallen below the boundary value temperature stored by the set temperature storage means. a third comparing means; a determining means for determining switching from a heating cycle to a defrosting cycle based on a set time elapsed signal from the first and second comparing means and a boundary value drop signal from the third comparing means; and a selection output means for controlling the refrigeration cycle from heating operation to defrosting operation according to the output of the determination means.

Effect: With this configuration, heating operation is ensured until a predetermined time has elapsed from the start of heating operation, and after that predetermined time has elapsed, the boundary value temperature is lowered, and after a predetermined time elapses, the boundary value temperature is switched according to the air volume. The defrosting operation is controlled by the set temperature storage means that stores the temperature and the temperature detected by the temperature detection means.

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 switching 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. 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, the pressure reducer 4, the outdoor heat exchanger 5, and the outdoor blower 8 constitute an outdoor unit A.

In addition, a microcomputer in which the indoor heat exchanger 3 and the indoor blower 7, a pipe temperature detection element 6, a timer function, a temperature adjustment function, etc. are programmed, is also provided.
2 (hereinafter abbreviated as microcomputer)
FIG. 3C) is installed in the indoor unit B. Here, the pipe temperature detection element 6 is attached at a location away from the wind circuit where it is not affected by the air blowing from the indoor 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 18 with a transformer 17, converts it into full-wave rectification with a diode bridge in the DC power generation unit 16, and creates a DC power supply that operates the microcomputer 22 with a regulator IC. There is. In the microcomputer 22, a reset circuit 23 is connected to the p□ port, and an oscillation circuit 26 is connected to the Pl and P2 ports. P
7. A scan signal is output from the P6 port, and the operation switch air volume switching section 24 and room temperature setting section 25 of the control operation section are output.
P3. P4. Predetermined control is performed by inputting various scan signals to the P5 port. A signal to operate the relay that drives the compressor 1 is output from the P11 boat, a signal to operate the relay that drives the four-way switching valve 2 is output from the P12 boat, and a signal that operates the relay that drives the outdoor blower 8 is output from the P13 port. A signal to operate the relay for driving the indoor blower 7 is output from ports P14 to P16. P
From the boats 17 to P20, a reference voltage for comparing the input from the suction sensor 29 and the room temperature is transmitted to the D/A converter 19.
The output of the comparator 15 which compares the reference voltage with the input of the suction sensor 29 is P21.
Entered into the boat. The microcomputer 22 receives the input from the room temperature setting section 25 of the control equipment section, compares it with the input from the P21 port, and performs 0N10FF control of the compressor 1. Air volume is H□, M8. As it switches to Lo, P22 to P
A Hi-multiply signal is output from the output port 24, and the reference voltage is switched according to the temperature stored in the resistor 9.degree. 10 of the set temperature storage means 28. The reference voltage and the signal of the temperature detection means 30 are compared by a comparator 27 corresponding to a third comparison means,
It is input to P26.

Comparing the configuration of FIG. 3 with the configuration of FIG. 1, the pipe temperature detection element 6, that is, the temperature detection means 30 is the temperature detection means of FIG. 1, and the comparator 27 is the third comparison means.
Resistors 9 and 10 serve as a set temperature storage means, and the air volume changeover switch 24 in the control equipment serves as an air volume change means.
3.14 is the set temperature switching means, and the microcomputer 22 is the first and second set time storage means and the first and second set time storage means shown in FIG.
time measuring means, first and second comparing means, determining means,
This corresponds to 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 TIIN, the discharge pressure of the compressor 1 is Pd, the suction pressure of the compressor 1 is P8, and the polytropic index is n (however, 1
Given the relationship <n<k, where k is an adiabatic compression index), 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 T is high, and each 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 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. 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. 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 as the frost progresses, As the temperature gradually decreases and frost formation occurs which significantly reduces the heating capacity, the temperature t of the inlet pipe of the indoor heat exchanger 3 extremely decreases. That is, the inlet pipe temperature t is the set pipe temperature 11 (air volume r-o)
If the temperature falls below this, the heating capacity will decrease and frost has progressed, so it will be necessary to defrost.

In addition, since this inlet pipe temperature is slightly affected by the air volume, as shown in Fig. 4, the air volume L0 (weak wind), the air volume M
e (medium wind), air volume Ht (strong wind), set pipe temperature to t.
j, t2. By changing to t3, frost formation can be detected more accurately.

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

That is, normal heating operation is started in step 1 of FIG. 5, and the microcomputer 22 counts a timer count for a predetermined time T1 (step 2). 1 hour)
This is to ensure heating operation, for example, forcibly turning on T1.
Continuous heating for hours is one way.

When the timer count is set, it is determined in step 3 whether the time T1 has elapsed. The heating operation is continued until the time T1 has elapsed.

Then, when the time T1 has elapsed, the microcomputer 2
2, a timer count for a predetermined time T2 is set. In this second timer count set, the pipe temperature t is set to the set pipe temperature (tl, t2, t3 by the air volume switching means).
) is used to measure the time T2 (for example, 1 minute) in which the pipe temperature t is continuously lower than the actual temperature, to prevent the pipe temperature t from being detected to be lower than the actual temperature due to noise, etc., and to prevent the defrosting operation from being started by mistake. It is provided for. Then, when this timer count is set, the air volume is determined. Air volume is L
(If the wind is weak), set the output of the P22 boat to H□ (step 5.6) and set the air volume to M. If (paralysis), P23
Set the port output to Hi (step 7.8); in other cases (air volume 81 strong wind), set the P24 port output to H□ (step 9). In this way, the set pipe temperature determined by the voltage formed by the partial pressure of resistors 9 and 10 in FIG.
2 to 14 are used to make it possible to change the set pipe temperature by changing 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 10.

Then, if the inlet pipe temperature t is lower than the set pipe temperature tx corresponding to each air volume (step 11), the comparator 27 outputs a Hi ratio output. When the conditions of step 11 are satisfied, it is determined in step 12 that 72 hours have elapsed. The heating operation is continued until 72 hours have elapsed, and if the inlet pipe temperature t is greater than the set pipe temperature tx before 72 hours have elapsed, the process returns to step 4 and the second timer counter is reset.

Then, when the conditions of step 12 are satisfied, step 13
The defrosting operation starts.

That is, the P11 to P16 boat 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.

Then, defrost is 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 in the outdoor heat exchanger is flowed, or a configuration in which a separate heat source is used to melt the lightning. 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-described configuration, the temperature of the refrigerant gas in the superheated region is detected at the indoor heat exchanger inlet pipe, correction is made according to the indoor air volume, and an appropriate defrosting operation is performed. This can be done with one temperature detection point, and the configuration is very simple.In addition, it is possible to judge whether the refrigerant has enough heat for heating at the inlet side of the indoor heat exchanger. Therefore, defrosting can be performed by reliably determining the presence or absence of actual heating capacity.

In other words, 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 in the middle part. By focusing on extremely high points and detecting the refrigerant temperature on the inlet side, it is possible to detect large temperature changes from non-frosting to frosting, and it is possible to draw out heating capacity close to the limit by detecting the temperature at one point. . 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.

Furthermore, 1. Because the control is such that static elimination operation does not start unless the pipe temperature of the indoor heat exchanger continuously falls below the set temperature, the pipe temperature may be detected to be lower than the actual temperature due to noise etc., and static elimination operation may be performed incorrectly. It's never even started.

[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. The 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 static electricity removal control device, and Fig. 5 is the circuit diagram of the defrosting control device. It is a flow chart showing operation details. 1... Compressor, 2... Four-way switching valve, 3...
・Indoor heat exchanger, 5...Outdoor heat exchanger, 6
...Piping temperature detection element, 9.1o...Setting temperature memory resistance, 12.13.14...Setting temperature switching resistance,
22... Microcomputer, 27... Name of comparator agent Patent attorney Toshio Nakao and one other person Figure 1 Figure 4 Time

Claims (1)

[Claims] 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 switches from the heating cycle to the defrosting cycle. a first time measuring means having a control device for switching the control device to a cycle, a first time measuring means for measuring the time from the start of heating operation of the compressor; and a first set time memory storing a preset time. means, first comparing means for detecting and outputting a match between the time detected by the first time measuring means and the time set in the first set time storage means, and the indoor heat exchanger during heating operation. a temperature detection means for detecting the temperature of a pipe connected to the refrigerant inlet side of the container; a set temperature storage means for storing a boundary value temperature for switching a heating cycle to a defrosting cycle; and a temperature detected by the temperature detection means; a second time measuring means for measuring the time when the temperature drops below a certain set temperature value stored in the set temperature storage means; a second set time storing 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; an air volume switching means for switching the air volume; and a set temperature according to each air volume. a set temperature switching means for switching; a third comparing means for detecting and outputting that the temperature detected by the temperature detecting means has fallen below a boundary value temperature stored in the set temperature storage means; determining means for determining switching from the heating cycle to the defrosting cycle based on the first and second set time elapsed signals from the comparing means and the boundary value drop signal from the third comparing 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 accordingly.