JPH0566493B2 - - Google Patents

Description

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

Prior 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, such a conventional configuration requires a plurality of temperature detection elements, and has the problem of complicating the circuit itself. Furthermore, in air conditioners, the amount of air blown inside the room is usually variably set arbitrarily, and for this reason, adding an air amount correction means to the conventional technology would further complicate 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.

Also, depending on the power supply frequency, the compression function differs between 50Hz and 60Hz, and in general, the pressure is higher at 60Hz, and even at the same indoor heat exchanger temperature,
The frosting conditions on the outdoor heat exchanger differed between Hz and 60Hz, making it impossible to accurately determine defrost.

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, as shown in FIG. temperature detection means for detecting the temperature of the pipe connected to the inlet side; set temperature storage means for storing the boundary value temperature for switching the heating cycle to the defrosting cycle; frequency discrimination means for discriminating different frequencies of the power supply based on the output; boundary value temperature switching means for switching the boundary value temperature of the set temperature storage means based on the output signal from the frequency discrimination means; and detection by the temperature detection means. determining whether to switch from the heating cycle to the defrosting cycle based on a boundary value drop signal from a comparison means that detects and outputs that the temperature has fallen below the boundary value temperature stored in the set temperature storage means; The apparatus includes selection output means for controlling the refrigeration cycle from heating operation to defrosting operation in accordance with the output of the determination means.

Operation With this configuration, the defrosting operation is controlled according to the set temperature storage means that stores the boundary value temperature according to the power supply frequency and the temperature detected by the temperature detection means.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 to 5.

FIG. 2 is a refrigeration cycle diagram showing one embodiment of the present invention.

In the figure, the refrigeration cycle is constructed by sequentially connecting a compressor 1, a four-way switching valve 2, an indoor heat exchanger 3, a pressure reducer 4, and an outdoor heat exchanger 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. In this case, during the heating operation, the refrigerant flows in the direction of the solid line arrow in the figure, and during the 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 (hereinafter referred to as
An operation control section (not shown) having an LSI (abbreviated as LSI) is provided in 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 indoor unit B.

Next, the operation control circuit configuration will be explained with reference to FIG. Here, the same parts as in FIG. 2 are given the same numbers and will be explained.

In the figure, C and D indicate an operation control section and a remote control section (hereinafter referred to as operation section), respectively, and the operation control section C includes a transformer 22 that steps down the AC power supply 21 and a DC power supply that converts AC into DC. A generating section 23, a DC power source generating section 23 that supplies direct current to the input power source of the LSI 24, a regular 25, a reference voltage generating circuit 26, a defrost setting circuit 27 that switches the operating temperature for defrosting, and the reference A comparison circuit 28 compares the reference composite input of the voltage generation circuit 26 and the defrosting setting circuit 27 with the input of the pipe temperature detection element 6, and each operation of the compressor 1, four-way switching valve 2, indoor blower 7, and outdoor blower 8 is controlled. An output circuit 29 consisting of a group of relay elements to be controlled, and a generation circuit 30 that creates basic timing for various signal processing of the LSI 24.
and a reset circuit 31 that controls various signal processing. Here, the regulator 25 is an LSI
The output circuit ₂₉ is connected to ports P ₁₁ to P ₁₆ , respectively, and the defrost setting circuit 27, which determines the operating temperature point for switching from heating operation to defrosting operation, is connected to port P ₂₁ . The comparator circuit 28 is connected to the port P ₃₁ , and the transmitting circuit 30 and the reset circuit 31 are connected to the ports P ₄₁ , P ₄₂ , P ₅₁
are connected to each.

The reference voltage generation circuit 26 includes a resistor 101,
102, the defrost setting circuit 27 is composed of a resistor 103 connected to port _P21 ,
Further, the output circuit 29 includes relay elements R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ connected to each port P ₁₁ to P ₁₆ . Relay element R ₁ corresponds to the compressor,
Relay element R ₂ corresponds to a four-way switching valve, relay element R ₃ corresponds to an outdoor blower, and relay elements R ₄ , R ₅ ,
_R6 corresponds to the "low speed", "medium speed", and "high speed" speed temperature terminals that change the air volume of the indoor blower.

Furthermore, 33 is an inverter IC circuit, and the LSI 2
4 port Po, and the DC power generation section 2
The waveform signal full-wave rectified by 3 is sent to the LSI 24.
Enter. Therefore, the LSI 24 can vary the power supply frequency from 50Hz to 50Hz, for example, depending on the period of this waveform signal.
Determine 60Hz, output the result to port P ₂₁ ,
The defrost setting circuit is operated and the reference synthesis input applied to the comparison circuit 28 is changed. In this example, when a high frequency of 60Hz is detected, "Hi" is output from port _P21 .
is set to output, increase the reference composite input voltage, and raise the boundary value temperature.

Further, 51 is an air temperature detection element for detecting the intake air temperature, 52 is an A/D conversion circuit including a plurality of resistor groups 110 to 115, and 53 is an input of the air temperature detection element 51 and the A/D conversion circuit 52. This is a comparison circuit that compares the inputs from the compressor 1 and outputs an operation/stop signal for the compressor 1.

The air temperature detection element 51 and the A/D conversion circuit 5
2 constitutes the function of a thermostat that adjusts the indoor temperature, the A/D conversion circuit 52 is connected to ports P ₇₁ to P ₇₄ of the LSI 24, and the output of the comparison circuit 53 is
Each is connected to port P ₈₁ of the LSI 24.
Since this room temperature control is not related to the gist of the present invention, detailed explanation will be omitted.

Next, the operation part D selects "low speed", "medium speed", "high speed",
An air volume switching operation section 41 equipped with "stop" selection switches S ₁ to S ₄ and a switch for setting the room temperature.
It is composed of a room temperature setting operation section 42 equipped with _S11 to _S14 . The air volume switching operation unit 41 and the room temperature setting operation unit 42 are connected to ports P ₆₁ to _{P 66} of the LSI 24.
are connected to each. By operating the air volume switching operation section 41 and the room temperature setting operation section 42, the operation contents are processed inside the LSI 24, and the output circuit 29 and the room temperature control related circuit section are operated.

Furthermore, the relationship between the above configuration and the configuration shown in FIG. 1 will be explained.

The pipe temperature detection element 6 corresponds to temperature detection means, and is connected to the inverter IC circuit 33 and the DC power generation section 23.
corresponds to a clock input means, the reference voltage generation circuit 26 and the defrost setting circuit 27 correspond to a set temperature storage means, the defrost setting circuit 27 corresponds to a boundary value temperature switching means, and the comparison circuit Reference numeral 28 corresponds to comparison means, output circuit 29 corresponds to selection output means, and four-way switching valve 2 corresponds to cycle switching means. The LSI 24 corresponds to frequency discrimination means and determination means.

Next, the operation from the start of the heating operation to the defrosting operation will be explained based on FIGS. 2 to 5.

The discharge refrigerant temperature of compressor 1 is Td, the suction refrigerant temperature of compressor 1 is Ts, the discharge pressure of compressor 1 is Pd, the suction pressure of compressor 1 is Ps, and the polytropic index is n (where 1<n<K In the relationship, K is the adiabatic compression index), then the discharge refrigerant temperature Td is expressed by the following equation.

Td=Ts・(Pd/Ps) ^n-1/n Therefore, when the outdoor heat exchanger 5 is not frosted, the suction refrigerant temperature Ts 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
It also goes down. Piping 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, but the temperature is actually lower than that of the discharged gas. This is the temperature that has decreased by a predetermined temperature due to heat loss in piping, etc.

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 t of the indoor heat exchanger 3 is both high, and gradually decreases as frosting progresses, and when frost formation that significantly reduces the heating capacity occurs, the inlet pipe temperature t of the indoor heat exchanger 3 decreases. decreases dramatically.
That is, if the inlet pipe temperature t becomes equal to or lower than the set pipe temperature _t1 , the heating capacity decreases, and since frost formation has progressed, it is necessary to defrost.

Also, regarding the power frequency, the capacity of the compressor 1 is different between 50Hz and 60Hz, and the capacity of the outdoor heat exchanger 5 is different.
The high pressure and discharge temperature during frost formation are also different. In other words, the inlet pipe temperature t of the indoor heat exchanger 3 is generally different between 50Hz and 60Hz, and the set pipe temperature _t1 is different from that of the indoor heat exchanger 3.
If defrost determination is not performed by switching between 50Hz and 60Hz, appropriate defrost detection cannot be performed depending on the power supply frequency, for example at 60Hz, and the heating capacity cannot be fully utilized.

In this way, since the inlet pipe temperature t 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 indoor blower 7, and the inlet pipe temperature t of the indoor heat exchanger 3 is Appropriate defrosting operation judgment can be made at both 50Hz and 60Hz.

Based on the above explanation, the control circuit shown in FIG. 3 controls the contents of the flowchart shown in FIG. 5. Here, for convenience of explanation, it is assumed that during the heating operation, the compressor, the four-way switching valve, the outdoor blower, and the relay elements R ₁ to _{R 4} of the indoor blower operated at "low speed" are operating.

That is, in step 1 of Fig. 5, it is determined whether the power supply frequency is 60Hz, and in step 2, it is determined whether the power supply frequency is 60Hz.
If it is Hz, set port P ₂₁ to Hi, if it is 50Hz,
Open port P ₂₁ . Specifically, the waveform signal from the inverter IC circuit 33 shown in FIG.
The frequency discrimination means in the LSI 24 makes the discrimination, and the LSI
Set port P ₂₁ on the output side of 24 to Hi at 60 Hz, raise the reference voltage created by the partial pressure of resistors 101 and 102, and set the set pipe temperature t ₁ to the power frequency.
It changes depending on 50Hz and 60Hz.

After that, heating operation is started in step 3,
The pipe temperature t is read by the pipe temperature detection element 6 (step 4), and the process moves to step 5, where it is determined whether the pipe temperature t is lower than the set pipe temperature t1 set in steps 1 and ₂ . Specifically, the comparison circuit 28 in FIG. 3 makes the determination.

When the conditions of step 5 are satisfied, the process moves to step 6 and defrosting operation is started. That is,
Each relay element R ₁ of the output circuit 29 shown in FIG.
R ₂ , R ₃ , and R ₄ are operated to switch the four-way switching valve 2, and if necessary, before that, 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. It goes without saying that a configuration in which the frost is allowed to flow or a configuration in which a separate heat source is used to melt the frost may also be used. Further, the compressor 1 may be operated continuously when switching to defrosting operation, and may be temporarily stopped before returning to heating operation.

Furthermore, the output status of port P ₂₁ according to the power frequency is set to "Hi" at 50Hz,
The setting value may be changed.

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 piping, and the temperature of the refrigerant gas in the superheated region is detected accurately without being affected by the indoor air volume. The defrosting operation can be performed with one temperature detection point, the configuration is very simple, and it can be determined whether the refrigerant has enough heat for heating at the inlet of the indoor heat exchanger. Since defrosting can be done on the side, it is possible to reliably determine whether there is actual heating capacity before defrosting. Furthermore, even if the power supply frequency differs, the temperature is changed to the boundary value according to the frequency, so defrosting can be performed reliably and reliability is improved.

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 to draw out the heating capacity close to the limit by detecting the temperature at one point. I can do it.

[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 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 compressor suction refrigerant temperature in the defrosting control device, and Fig. 5 is a diagram showing the relationship between the temperature of the refrigerant flowing into the indoor heat exchanger in the defrosting control device This is a flowchart showing the operation contents. 1... Compressor, 2... Four-way switching valve, 3... Indoor heat exchanger, 5... Outdoor heat exchanger, 6... Piping temperature detection element (temperature detection means), 23... DC power generation section (clock input means), 24... LSI (determination means), 26... reference voltage generation circuit (set temperature storage means), 27... defrost setting circuit (set temperature storage means), 28... comparison circuit ( means of comparison), 29...
Output circuit (selection output means), 30... oscillation circuit,
31...Reset circuit, 33...Inverter IC
circuit (clock input means).

Claims (1)

[Claims] 1. 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 switches from the heating cycle to the defrosting cycle. A control device for switching the heating cycle to a defrosting cycle, a temperature detection means for detecting the temperature of a portion of the pipe connected to the refrigerant inlet side of the indoor heat exchanger through which superheated refrigerant gas flows, and a boundary for switching the heating cycle to the defrosting cycle. Based on the set temperature storage means that stores the value temperature, the clock input means that inputs the power supply frequency, and the output from the clock input means,
frequency discrimination means for discriminating between different frequencies of the power source; boundary value temperature switching means for switching the boundary value temperature of the set temperature storage means according to an output signal from the frequency discrimination means; a determination means for determining switching from a heating cycle to a defrosting cycle based on a boundary value drop signal from a comparison means which detects and outputs a temperature drop below a boundary value stored in a temperature storage means; and an output of said determination means. What is claimed is: 1. A defrosting control device for a separate air conditioner, comprising an output device for driving the cycle switching device in accordance with the cycle switching device, and the control device is provided in an indoor unit.