Patent Application
20200363112
The present invention relates to an air conditioner that uses refrigerant with a low global warming potential (GWP).
In recent years, use of refrigerant with a low GWP (hereinafter referred to as low-GWP refrigerant) in air conditioners has been considered from the viewpoint of environmental protection. A dominant example of low-GWP refrigerant is a refrigerant mixture containing 1,2-difluoroethylene.
However, the related art giving consideration from the aspect of increasing the efficiency of air conditioners using the foregoing refrigerant is rarely found. For example, in the case of applying the foregoing refrigerant to the air conditioner disclosed in PTL 1 (Japanese Unexamined Patent Application Publication No. 2013-124848), there is an issue of how to achieve high efficiency.
An air conditioner according to a first aspect includes a compressor that compresses a refrigerant mixture containing at least 1,2-difluoroethylene, a motor that drives the compressor, and a connection unit that causes power to be supplied from an alternating-current (AC) power source to the motor without frequency conversion.
In the air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the compressor can be driven without interposing a power conversion device between the AC power source and the motor. Thus, it is possible to provide the air conditioner that is environmentally friendly and has a relatively inexpensive configuration.
An air conditioner according to a second aspect is the air conditioner according to the first aspect, in which the connection unit directly applies an AC voltage of the AC power source between at least two terminals of the motor.
An air conditioner according to a third aspect is the air conditioner according to the first aspect or the second aspect, in which the AC power source is a single-phase power source.
An air conditioner according to a fourth aspect is the air conditioner according to any one of the first aspect to the third aspect, in which one terminal of the motor is connected in series to an activation circuit.
An air conditioner according to a fifth aspect is the air conditioner according to the fourth aspect, in which the activation circuit is a circuit in which a positive temperature coefficient thermistor and an operation capacitor are connected in parallel to each other.
In the air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, after the compressor has been activated, the PTC thermistor self-heats and the resistance value thereof increases, and switching to an operation circuit substantially by the operation capacitor occurs. Thus, the compressor enters a state of being capable of outputting a rated torque at appropriate timing.
An air conditioner according to a sixth aspect is the air conditioner according to the first aspect or the second aspect, in which the AC power source is a three-phase power source.
This air conditioner does not require an activation circuit and thus the cost is relatively low.
An air conditioner according to a seventh aspect is the air conditioner according to any one of the first aspect to the sixth aspect, in which the motor is an induction motor.
In this air conditioner, the motor is capable of high output with relatively low cost, and thus the efficiency of the air conditioner can be increased.
In the air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the compressor can be driven without interposing a power conversion device between the AC power source and the motor. Thus, the air conditioner that is environmentally friendly and has a relatively inexpensive configuration can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) and a coefficient of performance (COP) equal to those of R410A is used.
Any one of various refrigerants such as refrigerant A, refrigerant B, refrigerant C, refrigerant D, and refrigerant E, details of these refrigerant are to be mentioned later, can be used as the refrigerant.
The refrigerant according to the present disclosure can be preferably used as a working fluid in a refrigerating machine.
The composition according to the present disclosure is suitable for use as an alternative refrigerant for HFC refrigerant such as R410A, R407C and R404 etc, or HCFC refrigerant such as R22 etc.
The tracer compound may be present in the refrigerant composition at a total concentration of about 10 parts per million (ppm) to about 1000 ppm. Preferably, the tracer compound is present in the refrigerant composition at a total concentration of about 30 ppm to about 500 ppm, and most preferably, the tracer compound is present at a total concentration of about 50 ppm to about 300 ppm.
Hereinafter, the refrigerants A to E, which are the refrigerants used in the present embodiment, will be described in detail.
In addition, each description of the following refrigerant A, refrigerant B, refrigerant C, refrigerant D, and refrigerant E is each independent. The alphabet which shows a point or a line segment, the number of an Examples, and the number of a comparative examples are all independent of each other among the refrigerant A, the refrigerant B, the refrigerant C, the refrigerant D, and the refrigerant E. For example, the first embodiment of the refrigerant A and the first embodiment of the refrigerant B are different embodiment from each other.
When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 85% or more relative to that of R410A, and a COP of 92.5% or more relative to that of R410A; furthermore, the refrigerant has an RCL of 40 g/m3 or more.
COP=(refrigerating capacity or heating capacity)/power consumption
COP=(refrigerating capacity or heating capacity)/power consumption
The results further indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points:
point P (20.5, 51.7, 27.8),
point S (21.9, 39.7, 38.4), and
point T (8.6, 51.6, 39.8),
or on these line segments,
In the above, the line segment ET is represented by coordinates (−0.0547z2−0.5327z+53.4, 0.0547z2−0.4673z+46.6, z), and the line segment TF is represented by coordinates
(−0.0982z2+0.9622z+40.931, 0.0982z2−1.9622z+59.069, z).
The air conditioner 1 has a refrigerant circuit 11 in which a compressor 100, a four-way switching valve 16, a heat-source-side heat exchanger 17, an expansion valve 18 serving as a decompression mechanism, and a utilization-side heat exchanger 13 are connected in a loop shape by refrigerant pipes.
In this embodiment, the refrigerant circuit 11 is filled with refrigerant for performing a vapor compression refrigeration cycle. The refrigerant is a refrigerant mixture containing 1,2-difluoroethylene, and any one of the above-described refrigerant A to refrigerant E can be used. The refrigerant circuit 11 is filled with refrigerating machine oil together with the refrigerant mixture.
In the refrigerant circuit 11, the utilization-side heat exchanger 13 belongs to the utilization unit 2. In addition, a utilization-side fan 14 is mounted in the utilization unit 2. The utilization-side fan 14 generates an air flow to the utilization-side heat exchanger 13.
A utilization-side communicator 35 and a utilization-side microcomputer 41 are mounted in the utilization unit 2. The utilization-side communicator 35 is connected to the utilization-side microcomputer 41.
The utilization-side communicator 35 is used by the utilization unit 2 to communicate with the heat source unit 3. The utilization-side microcomputer 41 is supplied with a control voltage even during a standby state in which the air conditioner 1 is not operating. Thus, the utilization-side microcomputer 41 is constantly activated.
In the refrigerant circuit 11, the compressor 100, the four-way switching valve 16, the heat-source-side heat exchanger 17, and the expansion valve 18 belong to the heat source unit 3. In addition, a heat-source-side fan 19 is mounted in the heat source unit 3. The heat-source-side fan 19 generates an air flow to the heat-source-side heat exchanger 17.
In addition, a connection unit 30, a heat-source-side communicator 36, and a heat-source-side microcomputer 42 are mounted in the heat source unit 3. The connection unit 30 and the heat-source-side communicator 36 are connected to the heat-source-side microcomputer 42.
(6-2) Configuration of connection unit 30
The motor 70 is an induction motor and includes a squirrel-cage rotor 71, and a stator 72 having a main winding 727 and an auxiliary winding 728. The squirrel-cage rotor 71 rotates following a rotating magnetic field generated by the stator 72.
The compressor 100 has an M terminal, an S terminal, and a C terminal. The M terminal and the C terminal are connected by the main winding 727. The S terminal and the C terminal are connected by the auxiliary winding 728.
The AC power source 90 and the compressor 100 are connected by power supply lines 901 and 902 that supply an AC voltage to the compressor 100. The power supply line 901 is connected to the C terminal via a thermostat 26.
The thermostat 26 detects a temperature of a room equipped with the air conditioner 1. The thermostat 26 opens the contact thereof when the room temperature is within a set temperature range and closes the contact when the room temperature is out of the set temperature range.
The power supply line 902 branches off into a first branch line 902A and a second branch line 902B. The first branch line 902A is connected to the M terminal, and the second branch line 902B is connected to the S terminal via an activation circuit 20.
The activation circuit 20 is a circuit in which a positive temperature coefficient (PTC) thermistor 21 and an operation capacitor 22 are connected in parallel to each other.
In this embodiment, the thermostat 26 connected to the power supply line 901 and the activation circuit 20 connected to the power supply line 902 are referred to as the connection unit 30.
In the operation circuit of the compressor 100 having the above-described configuration, turning on of the AC power source 90 causes a current to flow through the auxiliary winding 728 via the PTC thermistor 21 and the motor 70 to be activated.
After the motor 70 has been activated, the PTC thermistor 21 self-heats by using the current flowing therethrough, and the resistance value thereof increases. As a result, the operation capacitor 22, instead of the PTC thermistor 21, is connected to the auxiliary winding 728, and the state shifts to a stable operation state.
(6-4-1)
In the air conditioner 1 that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the compressor 100 can be driven without interposing a power conversion device between the AC power source 90 and the motor 70. Thus, it is possible to provide the air conditioner 1 that is environmentally friendly and has a relatively inexpensive configuration.
(6-4-2)
In the air conditioner 1 that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the connection between the auxiliary winding 728 and the activation circuit 20, which is a parallel circuit of the PTC thermistor 21 and the operation capacitor 22, makes it possible to achieve a large activation torque of the motor 70 of the compressor 100.
After the compressor 100 has been activated, the PTC thermistor 21 self-heats and the resistance value thereof increases, the state changes to a state where the operation capacitor 22 and the auxiliary winding 728 are substantially connected to each other, and the compressor 100 is operated at a constant rotation rate (power source frequency). Thus, the compressor 100 enters a state of being capable of outputting a rated torque. As described above, in the air conditioner 1, switching of connection to the operation capacitor 22 is performed at appropriate timing, and thus the efficiency of the compressor 100 can be increased.
(6-4-3)
The motor 70 is an induction motor and is capable of high output with relatively low cost, and thus the efficiency of the air conditioner 1 can be increased.
The connection unit 130 is a relay having contacts 130u, 130v, and 130w. The contact 130u opens or closes a power supply line 903 between an R terminal of the three-phase AC power source 190 and a U-phase winding Lu of the motor 170. The contact 130v opens or closes a power supply line 904 between an S terminal of the three-phase AC power source 190 and a V-phase winding Lv of the motor 170. The contact 130w opens or closes a power supply line 905 between a T terminal of the three-phase AC power source 190 and a W-phase winding Lw of the motor 170.
AC voltages are supplied from the R terminal, the S terminal, and the T terminal of the three-phase AC power source 190 to the corresponding U-phase winding Lu, the V-phase winding Lv, and the W-phase winding Lw of the motor 170. The AC voltage supplied to the V-phase winding Lv of the motor 170 has a phase difference of 120 degrees with respect to the AC voltage supplied to the U-phase winding Lu. Also, the AC voltage supplied to the W-phase winding Lw of the motor 170 has a phase difference of 120 degrees with respect to the AC voltage supplied to the V-phase winding Lv.
Thus, only the supply of AC voltages from the three-phase AC power source 190 to the motor 170 causes a rotating magnetic field to be generated in the stator 172, and the rotor 171 rotates following the rotating magnetic field. As a result, the compressor 200 is operated at a constant rotation rate (power source frequency). Thus, the operation circuit of the motor 170 does not require the activation circuit 20 according to the foregoing embodiment, and only a relay circuit of the connection unit 130 is used.
(6-6-1)
In the air conditioner 1 that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the compressor 200 can be driven without interposing a power conversion device between the three-phase AC power source 190 and the motor 170. Thus, it is possible to provide the air conditioner 1 that is environmentally friendly and has a relatively inexpensive configuration.
(6-6-2)
The motor 170 is an induction motor and is capable of high output with relatively low cost, and thus the efficiency of the air conditioner 1 can be increased.
An embodiment of the present disclosure has been described above. It is to be understood that various changes of the embodiment and details are possible without deviating from the gist and scope of the present disclosure described in the claims.
PTL 1: Japanese Unexamined Patent Application Publication No. 2013-124848
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-242183 | Dec 2017 | JP | national |
| 2017-242185 | Dec 2017 | JP | national |
| 2017-242186 | Dec 2017 | JP | national |
| 2017-242187 | Dec 2017 | JP | national |
| PCT/JP2018/037483 | Oct 2018 | JP | national |
| PCT/JP2018/038746 | Oct 2018 | JP | national |
| PCT/JP2018/038747 | Oct 2018 | JP | national |
| PCT/JP2018/038748 | Oct 2018 | JP | national |
| PCT/JP2018/038749 | Oct 2018 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16772961 | US | |
| Child | 16913454 | US |
