JPS5971966A - Air conditioner - 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 Technical Field The present invention relates to an air conditioner having a refrigerant compression cycle and whose capacity is variable by frequency conversion control.

Conventional technology A conventional air conditioner consists of an electric compressor that compresses refrigerant gas, an outdoor heat exchanger installed outdoors, an indoor heat exchanger installed indoors, and an outdoor heat exchanger. A pressure reducer is connected between the indoor heat exchanger and depressurizes the refrigerant gas, and the refrigerant gas from the electric compressor is sent to the outdoor heat exchanger during cooling and to the indoor heat exchanger during heating. It has a refrigerant compression cycle consisting of a switching valve that switches to When an air conditioner is operated to heat a room in winter, a frosty state occurs because refrigerant gas in a low temperature state passes through the outdoor heat exchanger. To remove this frosting, there is a need to warm up the outdoor heat exchanger. To do this, the operation of the air conditioner is switched from heating operation to cooling operation using a switching valve. When switching this switching valve,
Since the rotational speed of the electric compressor is constant, the pressure of the refrigerant gas coming out of the electric compressor remains at a high pressure. In this state, the switching valve instantaneously switches the refrigerant gas from the heating cycle to the cooling cycle, which generates a loud refrigerant gas noise. This can be heard very loudly in quiet places, such as late at night, and can help you get a good night's sleep.

Purpose The purpose of the present invention is to solve the above-mentioned technical problem, and to solve the above-mentioned technical problem, when switching the operation of an air conditioner from heating operation to cooling operation, in order to remove frost on an outdoor heat exchanger during winter, etc. To provide an air conditioner that prevents the generation of refrigerant gas noise.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. The refrigerant compression cycle of the air conditioner consists of an electric compressor 1 and an outdoor heat exchanger 4.
, an indoor heat exchanger 6, a pressure reducer 5, and a four-way switching valve 3. The electric l:iE compressor 1 includes a compressor tb and an electric motor 1a that rotates the compressor 1b. The outdoor heat exchanger 4 is installed outdoors. The indoor heat exchanger 6 is installed indoors. Outdoor heat exchanger 4 and indoor heat exchanger 6
The pressure reducer 5 connected between the two is for reducing the pressure of the refrigerant gas. The four-way switching valve 8 includes a port a1, a port b5, a port C1, and a boat d, and has the following structure. During cooling, refrigerant gas is sent from boat a to boat d, and refrigerant gas that has entered boat b is sent to port c. During heating, refrigerant gas is sent from boat a to boat b, and refrigerant gas that has entered boat d is sent to boat C.

In the refrigerant compression cycle during room cooling, refrigerant gas circulates in the direction of the dashed arrow in FIG. When the compressor tb rotates, the refrigerant gas that has entered from the line 31 is compressed by the compressor tb and is sent to the line 82 as a high-temperature, high-pressure gas. This high-temperature, high-pressure refrigerant gas is sent out from the boat d through the port mirror 1ffi of the four-way switching valve 8, and sent to the outdoor heat exchanger 4 via the line 34. The high-temperature, high-pressure refrigerant gas that has entered the outdoor heat exchanger 4 is cooled by air sent from the outdoor blower 7, and then passed through the pressure reducer 5.
to go into. The pressure reducer 5 reduces the pressure of the high-pressure refrigerant gas to a low-temperature, low-pressure gas. The low-temperature, low-pressure refrigerant gas cools the indoor heat exchanger 6. Indoor air is cooled by blowing air from the indoor fan 8 to the indoor heat exchanger 6. The refrigerant gas that has passed through the indoor heat exchanger 6 is heated and enters the boat b of the four-way switching valve 8 via a line 83.

The refrigerant gas that has entered boat b is sent out to line 81 through boat C.

Next, the refrigerant compression cycle during room heating will be explained. The solid arrows in FIG. 1 indicate the direction of circulation of refrigerant gas during heating. When the compressor 1b rotates, the refrigerant gas coming in from the line a1 is compressed by the compressor 1b and sent to the line 32 as a high-temperature, high-pressure gas. This high-temperature, high-pressure refrigerant gas is sent out from boat b through boat a of the four-way switching valve 8, and sent to the indoor heat exchanger 6 via line 83.

The high-temperature, high-pressure refrigerant gas that has entered the indoor heat exchanger 6 is cooled by air sent from the indoor blower 8 and enters the pressure reducer 5 . This wall air heats the room.

The pressure reducer 5 reduces the pressure of the high-pressure refrigerant gas to a low-temperature, low-pressure refrigerant gas. The low-temperature, low-pressure refrigerant gas cools the outdoor heat exchanger 4. By blowing air from the outdoor side blower 7 to the outdoor side heat exchanger 4, the outdoor side heat exchanger 4
The refrigerant gas inside is heated and enters the boat d of the four-way switching valve 8 via line 34. The refrigerant gas that entered boat d is
It is sent out to line 81 through boat c.

The processing circuit 11 realized by an arm microcomputer or the like has input terminals lNl-lN3 and output terminals 0UT1 to 0.
The clock oscillation circuit 1 includes a UT 6, a read-only memory that stores programs therein, a random access memory that temporarily stores data, and an arithmetic circuit that performs arithmetic operations.
Synchronous operation is performed by the pulse from 7. The indoor thermistor 18 detects the indoor temperature using an analog signal, inputs the analog signal to the digital/analog conversion circuit 14, and converts the output into a digital signal, which is then sent to the processing circuit 110.
The input window is input to the INI. Digital/analog conversion episode IiI! The temperature setting variable resistor 15 connected to t16 is provided to set the temperature to a temperature desired by a person in the room. An analog signal corresponding to the resistance value of the temperature setting variable resistor 15 is input to the digital/analog conversion circuit 16 . This analog signal is converted into an analog signal by a digital/analog conversion amount V@16 and input to the input terminal IN2 of the processing circuit 11. Processing circuit 1
10 The heating/cooling selector switch 20 connected to the input terminal IN8 is a switch for switching between indoor cooling and heating, and the power switch 21 connected to the input terminal IN4 is a switch for turning the processing circuit 11 on and off. .

The clock oscillation circuit 17 generates a reference clock signal for operating the processing circuit 11. The analog/digital conversion circuit 19 provides the temperature state of the outdoor heat exchanger 4 to the outdoor thermistor 18 as an analog signal, converts the analog signal into a digital signal, and inputs the digital signal to the processing circuit 110 input terminal IN5. let

Output terminal 0UT1.0UT2゜0UT8 of processing circuit 11
The output signal from is amplified by an amplifier circuit 12 and input to an inverter 10. AC power from the commercial AC power supply 22 is converted to DC by the converter 9, and is led out to electric wires 25 and 26. The inverter IO receives and receives DC power from the electric wires 25, 26, and outputs three-phase AC power to the electric wires 27, 28, 29 in response to the output signal of the amplifier circuit 12. The electric power @la is driven by the three-phase AC power, and the compressor 1aib is rotated.

The output signal from the output terminal 0UT4 of the processing circuit 11 is input to the outdoor blower drive circuit 24, and the outdoor blower drive circuit 2
The outdoor fan 7 is driven by the output signal No. 4. The output signal from the output terminal 0UT5 of the processing circuit 11 is input to the indoor blower drive circuit 28, and the indoor blower 8 is driven by the output signal of the indoor blower drive circuit 28. Output terminal 0UT
The output signal from 6 is input to the switching valve rotation 1@80, and the output signal from the switching valve drive port @30 controls each port a, b, c, d of the four-way switching valve 3 during cooling and heating. Switch at .

The operation of the processing circuit (1) will be explained based on the flowcharts of FIGS. 2 and 3 and FIG. 1.

In step nl, the power switch 21 shown in FIG.
When conductive, the processing circuit 11 operates, and the electric motors 1a,
The outdoor fan 7 and the indoor fan 8 are energized. By energizing the electric motor 1a, the compressor 1b rotates, and the air conditioner starts operating. In step n2, the processing circuit (1) enters an operating state in which it can respond to command signals from each circuit. In step n3, it is determined whether the air conditioner is in operation mode or stop mode. If the air conditioner is in operation mode, the process moves to step n4, and if it is in stop mode, the process moves to step n15. Operating mode refers to a state in which the electric compressor l is driven when the indoor temperature is not equal to the set temperature, and stop mode refers to a state in which the electric compressor l is stopped when the indoor temperature is equal to the set temperature. state of being. In step n4, the operation mode continues and the process moves to step n5.

In step n5, it is determined whether a flag signal for preparation for defrosting the outdoor heat exchanger 4 is set. In order to defrost, (a) a flag signal that forcibly gives a defrost preparation command to the processing circuit ll is set by operating the air conditioning/heating selector switch 2o, and (b) the temperature of the outdoor heat exchanger 4 is set. When the temperature falls below a predetermined temperature, a signal is sent to the input terminal IN of the processing circuit 11 via the outdoor thermistor 18 and the analog/digital conversion circuit 19.
In some cases, a flag signal that is input to the processing circuit 5 and gives a defrosting preparation command to the processing circuit 11 is set. When the processing circuit 11 sets the defrost preparation flag signal through such an operation, the process moves to step n6, where the frequency of the three-phase AC power output from the inverter lO is lowered, and the rotational speed of the electric compressor l is lowered. If defrosting is not to be performed, the process returns to step n4.

In step n7, the frequency of the three-phase AC power is set to a predetermined value, for example, when switching from heating operation to cooling operation during defrosting, when the electric compressor ■ does not generate refrigerant gas noise. It is determined whether or not the frequency is equal to the frequency value (about 80 Hz) of the three-phase AC power that gives a low rotational speed, and if it is equal to a predetermined value, the process moves to step n8, and if it is not equal, the process returns to step n6. . In step n8, the timer is set to 10 seconds and the process moves to step n9.

In step n9, it is determined by the timer operation whether the set time of 10 seconds has elapsed, and if it has elapsed, the process moves to step nlO. In step nlO, a defrost flag signal is set to defrost the frost on the outdoor heat exchanger 4, and the process moves to step nll.

In step nil, the four-way switching valve 8 is switched from the refrigerant compression cycle during heating to the refrigerant compression cycle during cooling, and the outdoor fan 7 and the indoor fan 8 are stopped. In this state, in step n12, the operation mode is set to increase the operating frequency of the electric compressor l. In step n1B, the load current of the electric compressor l is set to a predetermined value, for example 2.
It is determined whether or not it is less than OA. If it is less than 20A, the process moves to step n16, and if it exceeds 20A, the process moves to step n14. In step n14, the operation mode is set to lower the operating frequency, and the process returns to step n13. In step n16, it is determined whether the defrosting preparation flag has been reset, and if it has been reset, the process moves to step n17, and if it has not been reset, the process returns to step n12. The conditions for resetting the defrosting preparation flag are predetermined such that the defrosting preparation flag is reset when the outdoor heat exchanger 4 is warmed and defrosted and the temperature becomes 7 degrees Celsius or higher. In step n17, the operation mode is set to lower the operating frequency of the electric compressor l, and the process moves to step n18.

In step n18, it is determined whether the operating frequency is the predetermined minimum frequency, and if it is the minimum frequency, step n1
Step n17 if the frequency is higher than the crotch low frequency.
Return to In step n19, while the rotation speed of the electric compressor ■ is again in a low speed rotation state, the timer of the processing circuit 11 is set to 1.
0 seconds is set. In step n20, it is determined whether the timer set time of 10 seconds has elapsed, and if the time has elapsed, the process moves to step n21. In step n21,
10 seconds after the electric compressor 1 enters low-speed operation, the four-way switching valve 8 is switched from the refrigerant compression cycle for cooling to the refrigerant compression cycle for heating, and the outdoor fan 7 and the indoor fan 8 are driven again. and set it to heating mode. In step n2B, the operating mode is set to increase the operating frequency of the electric compressor 1. In step n24, the electric compressor 1
It is determined whether the load current is 20A or less, and if it is 208 or less, the process returns to step n3, and if it exceeds 20A, the process moves to step n25. In step n25, the operation mode is set to lower the operating frequency and the process returns to step n24.

Effects As described above, according to the present invention, when the room is heated by the air conditioner during the busy season, the air conditioner This eliminates refrigerant gas noise when switching from heating operation to cooling operation automatically or manually, eliminating the need for a restful night's sleep during quiet periods such as late at night.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIGS. 2 and 8 are flowcharts for explaining the operation of the processing circuit 11, respectively. 1... Electric compressor, 8... Four-way switching valve, 4... Outdoor heat exchanger, 5... Pressure reducer, 6... Indoor heat exchanger, 7... Outdoor blower , 8... Indoor blower, 9
...Converter, 10...Inverter, 11...
Processing circuit, 12... Amplification circuit, 1B... Indoor thermistor, 14, 16° 19... Analog/digital conversion circuit, 15... Variable resistance for temperature setting, 17... Clock oscillation circuit, 18 ...Outdoor thermistor, 20...
Air conditioning/heating selector switch, 21...Power switch, 22.
...Commercial AC power supply, 28...Indoor blower drive circuit,
24...Outdoor side blower drive circuit, 25.26, 27,
28.29...Electric wire, 30...Four-way switching valve drive circuit, 31-34...Line agent Patent attorney Kei Nishi

Claims (1)

[Claims] An electric compressor that compresses refrigerant gas, an outdoor heat exchanger installed outdoors, an indoor heat exchanger installed indoors, an outdoor heat exchanger and an indoor heat exchanger A pressure reducer is connected between the electric compressor and the refrigerant gas to reduce the pressure of the refrigerant gas, and the refrigerant gas from the electric compressor is sent to the outdoor heat exchanger and the indoor heat exchanger. In an air conditioner that has a refrigerant compression cycle consisting of a switching valve that changes the rotation speed of the electric compressor to An air conditioner comprising: a control means for controlling the air conditioner to lower the air conditioner.