JP6428221B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner that can achieve both energy saving and comfort.

  When performing cooling operation or heating operation with an air conditioner, the operation capacity of the compressor is determined and driven according to the temperature difference between the set temperature determined by the user and the room temperature. In such an air conditioner, after the room temperature reaches the set temperature, if the room temperature is lower than the set temperature by a predetermined temperature (for example, 1 ° C.) during the cooling operation, the room temperature is decreased during the heating operation. When the temperature is higher than the set temperature by a predetermined temperature, the so-called thermo-off state in which the compressor and the indoor fan are stopped is generally set. This transition to the thermo-off state is executed after a certain time (for example, 3 minutes) has elapsed since the room temperature has become a predetermined temperature lower or higher than the set temperature so that the entire room becomes a temperature close to the set temperature. There is.

  However, in a normal air conditioner, since the suction temperature detected by the indoor unit is regarded as room temperature, control is performed, so the detected suction temperature may not match the temperature of the entire room due to differences in the airflow distribution in the room. . For example, if a so-called air current short circuit is generated in which air blown out from the air outlet of the indoor unit is directly drawn from the air inlet of the indoor unit during heating operation, the detected suction temperature becomes higher than the temperature of the entire room. In such a case, if the timing for setting the thermo-off state is that the room temperature is a predetermined temperature lower or higher than the set temperature after a certain time has elapsed, the temperature of the entire room is not close to the set temperature. Nevertheless, the thermo-off state has occurred, and there is a risk that comfort may be impaired.

  In order to solve the above problems, an air conditioner that improves comfort by changing the timing of shifting to the thermo-off state has been proposed (for example, Patent Document 1). In the air conditioner described in Patent Document 1, a first thermo-off temperature having a small temperature difference from the set temperature, a long timer corresponding to the first thermo-off temperature, a second thermo-off temperature having a large temperature difference from the set temperature, A short timer corresponding to the second thermo-off temperature is set. When the compressor is driven at the minimum operating capacity, the timer corresponding to each thermo-off temperature is activated when the room temperature reaches each thermo-off temperature, and when the time measurement by the timer is completed, the thermo-off state is established.

  In the air conditioner described in Patent Literature 1, when the temperature difference between the room temperature and the set temperature is small, the time until the thermo-off state is increased, and when the temperature difference between the room temperature and the set temperature is large, the thermo-off state is established. The time until is shortened. Therefore, the thermo-off state is entered after the entire room reaches a temperature close to the set temperature, and comfort is improved.

JP-A-6-11173

  In the air conditioner described in Patent Literature 1, since two thermo-off temperatures having different temperature differences from the set temperature are set as described above, the room temperature reaches the second thermo-off temperature having a large temperature difference from the set temperature. In this case, until the thermo-off state is reached, the air conditioner is operated while the room temperature is maintained higher than the second thermo-off temperature, and there is a problem that energy saving performance is deteriorated.

  The present invention solves the above-described problems, and an object thereof is to provide an air conditioner that can achieve both energy saving and comfort.

  In order to solve the above problems, an air conditioner of the present invention includes an outdoor unit having a compressor capable of changing an operating capacity, an indoor heat exchanger, an indoor fan, and an indoor unit having a room temperature sensor for detecting a room temperature. And a refrigerant circuit in which the outdoor unit and the indoor unit are connected by a refrigerant pipe, and a control unit that periodically takes in the room temperature detected by the room temperature sensor and controls the driving of the compressor and the indoor fan. The control means calculates the room temperature change rate that is the time change rate of the captured room temperature, and when the captured room temperature reaches a predetermined thermo-off temperature, the compression is performed when the operating capacity of the compressor is the minimum operating capacity. When the compressor and the indoor fan are stopped and the compressor operating capacity is not the minimum operating capacity, if the room temperature change rate calculated immediately before the room temperature reaches the thermo-off temperature is greater than or equal to a predetermined threshold change rate, the compressor When the room temperature change rate calculated immediately before the room temperature reaches the thermo-off temperature is less than a predetermined threshold change rate, the operating capacity of the compressor is reduced.

  According to the air conditioner of the present invention configured as described above, if the operating capacity of the compressor is the minimum operating capacity when the room temperature reaches the thermo-off temperature, the thermo-off state is set, and the operating capacity of the compressor is the minimum operating capacity. Otherwise, if the room temperature change rate is equal to or higher than the threshold change rate, the thermo-off state is set. If the room temperature change rate is less than the threshold change rate, the operating capacity of the compressor is reduced without entering the thermo-off state. Thereby, when there exists a possibility that energy-saving property may deteriorate due to the air conditioner continuing to operate in a state where the room temperature greatly exceeds the thermo-off temperature, it is possible to quickly improve the energy-saving property as a thermo-off state. Also, if the air conditioner does not continue to operate when the room temperature is much higher than the thermo-off temperature, the compressor's operating capacity is reduced and the compressor is continuously driven and the indoor fan is driven without entering the thermo-off state. By continuing to do so, the user's comfort can be improved.

It is explanatory drawing of the air conditioner in embodiment of this invention, (A) is a refrigerant circuit figure, (B) is a block diagram of an indoor unit control means. It is a time chart for demonstrating the thermo-off control according to the difference of the change of room temperature in embodiment of this invention. It is a thermo-off operation | movement table in embodiment of this invention. It is a flowchart which shows the flow of a process in the indoor unit control part in embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, an air conditioner in which one outdoor unit and one indoor unit are connected by two refrigerant pipes will be described as an example. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  As shown in FIG. 1A, an air conditioner 1 according to this embodiment includes an outdoor unit 2 installed outdoors, and an indoor unit installed indoors and connected to the outdoor unit 2 with a liquid pipe 4 and a gas pipe 5. Machine 3 is provided. Specifically, the liquid pipe 4 has one end connected to the closing valve 25 of the outdoor unit 2 and the other end connected to the liquid pipe connecting portion 33 of the indoor unit 3. The gas pipe 5 has one end connected to the closing valve 26 of the outdoor unit 2 and the other end connected to the gas pipe connecting portion 34 of the indoor unit 3. The refrigerant circuit 10 of the air conditioner 1 is configured as described above.

  First, the outdoor unit 2 will be described. The outdoor unit 2 is connected to a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor fan 24, a closing valve 25 to which one end of the liquid pipe 4 is connected, and one end of the gas pipe 5. A closing valve 26 and an expansion valve 27 are provided. And these each apparatus except the outdoor fan 24 is mutually connected by each refrigerant | coolant piping explained in full detail below, and the outdoor unit refrigerant circuit 10a which makes a part of the refrigerant circuit 10 is comprised.

  The compressor 21 is a variable capacity compressor capable of changing the operating capacity by controlling the rotation speed by an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 by a discharge pipe 61. The refrigerant suction side of the compressor 21 is connected to the port c of the four-way valve 22 by a suction pipe 66.

  The four-way valve 22 is a valve for switching the direction in which the refrigerant flows, and includes four ports a, b, c, and d. The port a is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 61 as described above. The port b is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 23 by a refrigerant pipe 62. The port c is connected to the refrigerant suction side of the compressor 21 by the suction pipe 66 as described above. The port d is connected to the shutoff valve 26 and the outdoor unit gas pipe 64.

  The outdoor heat exchanger 23 exchanges heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 24 described later. As described above, one refrigerant inlet / outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 by the refrigerant pipe 62, and the other refrigerant inlet / outlet is connected to the closing valve 25 by the outdoor unit liquid pipe 63.

  The expansion valve 27 is an electronic expansion valve, for example. The expansion valve 27 adjusts the amount of refrigerant flowing into the outdoor heat exchanger 23 or the amount of refrigerant flowing out of the outdoor heat exchanger 23 by adjusting the opening degree thereof.

  The outdoor fan 24 is formed of a resin material and is disposed in the vicinity of the outdoor heat exchanger 23. The outdoor fan 24 is rotated by a fan motor (not shown) to take outside air from a suction port (not shown) of the outdoor unit 2 into the outdoor unit 2, and the outdoor air exchanged heat with the refrigerant in the outdoor heat exchanger 23 is shown in the illustration of the outdoor unit 2. Not discharged from the blower outlet to the outside of the outdoor unit 2.

  In addition to the configuration described above, the outdoor unit 2 is provided with various sensors. As shown in FIG. 1A, the discharge pipe 61 includes a high-pressure sensor 71 that detects the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature sensor that detects the temperature of the refrigerant discharged from the compressor 21. 73 is provided. The suction pipe 66 is provided with a low pressure sensor 72 that detects the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor 74 that detects the temperature of the refrigerant sucked into the compressor 21.

  Between the outdoor heat exchanger 23 and the expansion valve 27 in the outdoor unit liquid pipe 63, a heat exchange temperature sensor for detecting the temperature of the refrigerant flowing out of the outdoor heat exchanger 23 or flowing into the outdoor heat exchanger 23. 75 is provided. An outdoor air temperature sensor 76 that detects the temperature of the outside air flowing into the outdoor unit 2, that is, the outside air temperature, is provided in the vicinity of a suction port (not shown) of the outdoor unit 2.

  Next, the indoor unit 3 will be described with reference to FIG. The indoor unit 3 includes an indoor heat exchanger 31, an indoor fan 32, a liquid pipe connection portion 33 to which the other end of the liquid pipe 4 is connected, and a gas pipe connection portion 34 to which the other end of the gas pipe 5 is connected. I have. And these each apparatus except the indoor fan 32 is mutually connected by each refrigerant | coolant piping explained in full detail below, and the indoor unit refrigerant circuit 10b which makes a part of refrigerant circuit 10 is comprised.

  The indoor heat exchanger 31 exchanges heat between indoor air taken into the indoor unit 3 from a suction port (not shown) of the indoor unit 3 by rotation of a refrigerant and an indoor fan 32 to be described later. An indoor unit liquid pipe 67 is connected to the pipe connecting part 33, and the other refrigerant inlet / outlet is connected to the gas pipe connecting part 34 via an indoor unit gas pipe 68. The indoor heat exchanger 31 functions as an evaporator when the indoor unit 3 performs a cooling operation, and functions as a condenser when the indoor unit 3 performs a heating operation.

  In addition, in the liquid pipe connection part 33 and the gas pipe connection part 34, each refrigerant | coolant piping is connected by welding, a flare nut, etc.

  The indoor fan 32 is formed of a resin material and is disposed in the vicinity of the indoor heat exchanger 31. The indoor fan 31 is rotated by a fan motor (not shown) so that indoor air is taken into the indoor unit 3 from a suction port (not shown) of the indoor unit 3, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is taken into the indoor unit. 3 blows out into the room from a blower outlet (not shown).

  In addition to the configuration described above, the indoor unit 3 is provided with various sensors. The indoor unit liquid pipe 67 is provided with a liquid side temperature sensor 77 that detects the temperature of the refrigerant flowing into or out of the indoor heat exchanger 31. The indoor unit gas pipe 68 is provided with a gas side temperature sensor 78 that detects the temperature of the refrigerant flowing out of the indoor heat exchanger 31 or flowing into the indoor heat exchanger 31. A room temperature sensor 79 for detecting the temperature of the indoor air flowing into the indoor unit 3, that is, the room temperature, is provided near the suction port (not shown) of the indoor unit 3.

  The indoor unit 3 includes an indoor unit control means 100. The indoor unit control means 100 is mounted on a control board stored in an electrical component box (not shown) of the indoor unit 3. As shown in FIG. 1B, the indoor unit control means 100 includes a CPU 110, a storage unit 120, a communication unit 130, and a sensor input unit 140.

  The storage unit 120 includes a ROM and a RAM, and stores a control program for the indoor unit 3, detection values corresponding to detection signals from various sensors, a control state of the indoor fan 32, and the like. Although not shown, the storage unit 120 stores a rotation speed table in which a rotation speed code is assigned for each rotation speed of the compressor 21. In this rotational speed table, the rotational speed of the compressor 21 is determined by dividing it into a plurality of rotational speed codes between the maximum rotational speed and the minimum rotational speed determined by the compressor 21, for example, the minimum rotational speed. The number of rotations code corresponding to the number of rotations is “1”, the number of rotations code corresponding to the maximum number of rotations is “30”, and the compressor increases every time the number of rotations increases from 1 to 30. Assign a rotation number of 21.

  The communication unit 130 is an interface for performing communication with an outdoor unit control unit (not shown) of the outdoor unit 2. The sensor input unit 140 captures detection results from various sensors of the indoor unit 3 and outputs them to the CPU 110.

  CPU110 takes in the detection result in each sensor of indoor unit 3 mentioned above via sensor input part 140. FIG. Further, the CPU 110 takes in a signal related to control transmitted from the outdoor unit 2 via the communication unit 130. In addition, the CPU 110 performs drive control of the indoor fan 32 based on the acquired detection result and control signal.

  Further, the CPU 110 calculates a temperature difference between the set temperature set by the user by operating a remote controller (not shown) and the room temperature detected by the room temperature sensor 79, and stores the rotation speed table stored in the storage unit 120 described above. The rotation speed code corresponding to the temperature difference calculated with reference to is extracted, and a drive instruction signal for the compressor 21 based on this is transmitted to the outdoor unit 2 via the communication unit 130. The outdoor unit 2 controls the drive of the compressor 21 based on the received drive instruction signal. The operation capacity control of the compressor 21 is performed by the above operation.

Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 10 during the air conditioning operation of the air conditioner 1 in the present embodiment will be described with reference to FIG. In the following description, the case where the indoor unit 3 performs the cooling operation will be described first, and then the case where the indoor unit 3 performs the heating operation will be described. In FIG. 1A, the solid line arrows indicate the refrigerant flow during the cooling operation, and the broken line arrows indicate the refrigerant flow during the heating operation.
<Cooling operation>
When the indoor unit 3 performs a cooling operation, as shown in FIG. 1A, the four-way valve 22 is in a state indicated by a solid line, that is, the port a and the port b of the four-way valve 22 communicate with each other, and the port c And so that port d communicates. Thereby, a refrigerant | coolant circulates in the direction shown as a solid line arrow in the refrigerant circuit 10, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 31 functions as an evaporator.

  The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 and flows into the four-way valve 22, flows from the four-way valve 22 through the refrigerant pipe 62, and flows into the outdoor heat exchanger 23. The refrigerant flowing into the outdoor heat exchanger 23 is condensed by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 24. The refrigerant flowing out of the outdoor heat exchanger 23 into the outdoor unit liquid pipe 63 is decompressed when passing through the expansion valve 27 and flows into the liquid pipe 4 through the closing valve 25.

  The refrigerant flowing through the liquid pipe 4 and flowing into the indoor unit 3 through the liquid side connection portion 33 flows through the indoor unit liquid pipe 67 and into the indoor heat exchanger 31, and enters the indoor unit 3 by the rotation of the indoor fan 32. Evaporates by exchanging heat with the indoor air taken in. In this way, the indoor heat exchanger 31 functions as an evaporator, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown into the room from a blower outlet (not shown), so that the indoor unit 3 is installed. The room is cooled.

The refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit gas pipe 68 and flows into the gas pipe 5 through the gas side connection portion 34. The refrigerant flowing through the gas pipe 5 and flowing into the outdoor unit 2 through the closing valve 26 sequentially flows through the outdoor unit gas pipe 64, the four-way valve 22, and the suction pipe 66, and is sucked into the compressor 21 and compressed again.
<Heating operation>
When the indoor unit 3 performs the heating operation, as shown in FIG. 1A, the four-way valve 22 is indicated by a broken line, that is, the port a and the port d of the four-way valve 22 communicate with each other, and the port b And so that port c communicates. Thereby, a refrigerant | coolant circulates in the direction shown with a broken-line arrow in the refrigerant circuit 10, the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchanger 31 functions as a condenser.

  The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 and flows into the four-way valve 22, flows from the four-way valve 22 through the outdoor unit gas pipe 64, and flows into the gas pipe 5 through the closing valve 26. The refrigerant flowing through the gas pipe 5 flows into the indoor unit 3 through the gas pipe connection part 34.

  The refrigerant flowing into the indoor unit 3 flows through the indoor unit gas pipe 68 and flows into the indoor heat exchanger 31, and condenses by exchanging heat with the indoor air taken into the indoor unit 3 by the rotation of the indoor fan 32. . As described above, the indoor heat exchanger 31 functions as a condenser, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown into the room from a blower outlet (not shown), so that the indoor unit 3 is installed. The heated room is heated.

  The refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit liquid pipe 67 and flows into the liquid pipe 4 through the liquid pipe connecting portion 33. The refrigerant flowing through the liquid pipe 4 and flowing into the outdoor unit 2 through the closing valve 25 is decompressed when flowing through the outdoor unit liquid pipe 63 and passing through the expansion valve 27.

  The refrigerant that has flowed into the outdoor heat exchanger 23 through the expansion valve 27 evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 24. The refrigerant that has flowed out of the outdoor heat exchanger 23 into the refrigerant pipe 62 flows through the four-way valve 22 and the suction pipe 66, is sucked into the compressor 21, and is compressed again.

  Next, when the air conditioner 1 performs the cooling operation or the heating operation described above with reference to FIGS. 2 to 4, a problem that occurs when performing control to bring the room temperature detected by the room temperature sensor 79 closer to the set temperature. The operation of the present invention for solving this problem will be described.

  First, a problem that occurs when the air conditioner 1 performs control to bring the room temperature close to the set temperature will be described with reference to FIG. In FIG. 2, the time chart which shows the room temperature change when the air conditioner 1 is performing heating operation as an example is shown. In FIG. 2, Ti is room temperature, Tg is a set temperature, Tg1 is a thermo-off temperature higher than Tg by a predetermined temperature (eg, 1 ° C.), Tg 2 is a thermo-on temperature lower than Tg by a predetermined temperature (eg, 1 ° C.), and Tir is a unit time ta. The amount of change Ti of room temperature Ti (for example, 1 minute) (hereinafter referred to as room temperature change rate Tir; Tir = ΔTi / ta) is shown.

  When the air conditioner 1 starts the heating operation according to the user's instruction, the indoor fan 32 is activated, and the compressor 21 has an operating capacity corresponding to the temperature difference between the set temperature Tg determined by the user and the current room temperature Ti. Start with. Specifically, as described above, the CPU 110 of the indoor unit control unit 100 calculates the temperature difference between the set temperature Tg and the room temperature Ti captured from the room temperature sensor 79 via the sensor input unit 140, and the storage unit 120. The rotation number code corresponding to the temperature difference calculated with reference to the rotation number table stored in is extracted, and a drive instruction signal for the compressor 21 based on this is transmitted to the outdoor unit 2 via the communication unit 130. .

  When the compressor 21 is started and the heating operation is started as described above, the room temperature Ti rises. When the room temperature Ti reaches the set temperature Tg, the CPU 110 transmits a drive instruction signal based on a rotational speed code lower than the current rotational speed code to the outdoor unit 2 to reduce the rotational speed of the compressor 21. Thus, the operating capacity of the compressor 21 is reduced. The rotation speed of the compressor 21 is reduced by, for example, reducing the rotation speed code by one step every unit time (for example, every minute).

  Even if the compressor 21 is controlled as described above, when the room temperature Ti reaches the thermo-off temperature Tg1, if the compressor 21 is driven at the minimum rotational speed, that is, is driven at the minimum operating capacity, the CPU 110 will be the indoor fan 32. The outdoor unit 2 is instructed to stop the compressor 21 and the air conditioner 1 is put into the thermo-off state. By setting the air conditioner 1 to the thermo-off state, the room temperature Ti decreases and approaches the set temperature Tg. And if room temperature Ti falls to thermo-on temperature Tg2, CPU110 will restart the indoor fan 32 and the compressor 21, and will make the air conditioner 1 into a thermo-on state. Thereby, the room temperature Ti rises again and approaches the set temperature Tg.

  On the other hand, even if the rotation speed of the compressor 21 is decreased, when the room temperature Ti reaches the thermo-off temperature Tg1, if the compressor 21 is driven at the minimum rotation speed, that is, not driven at the minimum operating capacity, the CPU 110 The outdoor unit 2 is instructed to decrease the rotational speed of 21 per unit time. By reducing the rotational speed of the compressor 21 and reducing the operating capacity, the room temperature Ti becomes equal to or lower than the thermo-off temperature Tg1 and approaches the set temperature Tg.

  As described above, when the air conditioner 1 is controlled to be in the thermo-off state or the thermo-on state so that the room temperature Ti is always close to the set temperature Tg, the compression at the start of the heating operation or after the thermo-on is performed as shown in FIG. When the room temperature Ti suddenly rises due to the rotational speed of the machine 21 or the air conditioning load of the room where the indoor unit 3 is installed, that is, when the room temperature change rate Tir is large, the room temperature Ti is the thermo-off temperature. From time t1 when reaching Tg1 to time t2 when the rotation speed of the compressor 21 is decreased per unit time and the room temperature Ti becomes equal to or lower than the thermo-off temperature Tg1, the room temperature Ti greatly exceeds the thermo-off temperature Tg1 and energy saving is achieved. May be getting worse.

  Therefore, in the air conditioner 1 of the present invention, when the room temperature Ti reaches the thermo-off temperature Tg1, the compressor 21 is stopped if the compressor 21 is driven at the minimum operating capacity. If the compressor 21 is not driven at the minimum operating capacity, the compression is performed when the room temperature change rate Tir is equal to or higher than a predetermined threshold change rate, that is, when the room temperature Ti is changed as shown in FIG. The machine 21 is stopped, and when the room temperature change rate Tir is less than the threshold change rate, that is, when the room temperature Ti changes as shown in FIG. 2b, the operating capacity of the compressor 21 is reduced.

  2B, when the room temperature Ti rises more slowly than that of FIG. 2A, that is, when the room temperature change rate Tir is small (less than the threshold change rate), the temperature is equal to or higher than the thermo-off temperature Tg1 at time t3. If the operating capacity of the compressor 21 is not the minimum operating capacity, the operating capacity of the compressor 21 is reduced. At this time, if the room temperature Ti becomes equal to or lower than the thermo-off temperature Tg1 before the compressor 21 reaches the minimum operating capacity (time t4 of b1 in FIG. 2), the compressor 21 is kept until the room temperature Ti becomes the set temperature Tg after time t4. If the compressor 21 reaches the minimum operating capacity, the driving of the compressor 21 is maintained in that state. If the compressor 21 reaches the minimum operating capacity before the room temperature Ti becomes equal to or lower than the thermo-off temperature Tg1 (time t5 of b2 in FIG. 2), the compressor 21 is stopped at time t5 and the indoor fan 32 is also stopped. The air conditioner 1 is put into a thermo-off state.

  Next, the thermo-off operation table 200 used by the CPU 110 when performing the above-described control related to thermo-off will be described in detail with reference to FIG. 3, in addition to the room temperature change rate Tir described above, the operating capacity of the compressor 21 is C, the minimum operating capacity of the compressor 21 is Cmin, and the threshold change rate which is a threshold value of the room temperature change rate Tir is Ts (for example, 1 ° C./1 minute). The thermo-off operation table 200 is determined in advance by a test or the like and stored in the storage unit 120 in advance. The minimum operating capacity Cmin is the compressor operating capacity C when the compressor 21 is driven at a rotational speed corresponding to the minimum rotational speed code 1 in the rotational speed table described above.

  In the thermo-off operation table 200, the operation of the compressor 21 that the CPU 110 of the indoor unit 3 instructs the outdoor unit 2 and the operation of the indoor fan 32 are determined according to the compressor operating capacity C and the room temperature change rate Tir. It is a thing. Specifically, the room temperature change rate Tir is greater than or equal to the threshold change rate Ts when the compressor operating capacity C is the same as the minimum operating capacity Cmin and when the compressor operating capacity C is greater than the minimum operating capacity Cmin. The operation of the compressor 21 and the operation of the indoor fan 32 are determined by dividing into a case where the room temperature change rate Tir is greater than 0 and less than the threshold change rate Ts.

  As shown in FIG. 3, in the thermo-off operation table 200, when the compressor operating capacity C is the minimum operating capacity Cmin, the compressor 21 and the indoor fan 32 are stopped regardless of the room temperature change rate Tir. The air conditioner 1 is put into a thermo-off state. When the compressor operating capacity C is larger than the minimum operating capacity Cmin, when the room temperature change rate Tir is equal to or greater than the threshold change rate Ts, the compressor 21 and the indoor fan 32 are stopped, that is, the air conditioner 1 is turned off. When the thermo-off state is set and the room temperature change rate Tir is less than the super-threshold change rate Ts, the compressor operating capacity C is gradually reduced and the indoor fan 32 is continuously driven.

  Next, control related to thermo-off when the air conditioner 1 of the present embodiment is operating will be described with reference to FIGS. 1 to 4. FIG. 4 shows the flow of processing performed by the CPU 110 of the indoor unit control unit 100 when executing control related to thermo-off. In FIG. 4, ST represents a process step, and the number following this represents a step number. In FIG. 4, the processing related to the present invention is mainly described. Other processing, for example, control of the air conditioner 1 such as control related to the pressure and temperature of the refrigerant circuit 10 mainly performed by the outdoor unit 2 is performed. Description of processing related to general control is omitted.

  If there is an air conditioning operation start instruction from the user, the CPU 110 activates the indoor fan 32 and instructs the outdoor unit 2 to activate the compressor 21 via the communication unit 130 (ST1). As described above, the CPU 110 calculates the temperature difference between the set temperature Tg instructed by the user and the room temperature Ti acquired from the room temperature sensor 79 via the sensor input unit 140, and stores the rotation stored in the storage unit 120. The rotation number code corresponding to the calculated temperature difference is extracted with reference to the number table, and a drive instruction signal for the compressor 21 based on this is transmitted to the outdoor unit 2 via the communication unit 130.

  Next, the CPU 110 determines whether or not the room temperature Ti captured from the room temperature sensor 79 via the sensor input unit 140 is equal to or higher than the set temperature Tg during the heating operation, and is equal to or lower than the set temperature Tg during the cooling operation. (ST2). The CPU 110 fetches the room temperature Ti from the room temperature sensor 79 periodically (for example, every minute) and stores it in the storage unit 120 in time series.

  If the room temperature Ti is not less than the set temperature temperature Tg or less than the set temperature temperature Tg (ST2-No), the CPU 110 returns the process to ST2, and maintains driving of the indoor fan 32 and the compressor 21 under the conditions set in ST1. To do. If the room temperature Ti is not less than the set temperature temperature Tg or not more than the set temperature temperature Tg (ST2-Yes), the CPU 110 instructs the outdoor unit 2 to reduce the operation capacity of the compressor 21 (ST3). Specifically, CPU 110 extracts a rotation speed code that is one step lower than the rotation speed code determined in ST1 from the rotation speed table, and outputs a drive instruction signal for compressor 21 based on this to the outdoor unit via communication unit 130. 2 to send.

  Next, the CPU 110 determines whether or not the captured room temperature Ti is equal to or higher than the thermo-off temperature Tg1 during the heating operation, and whether or not the captured room temperature Ti is equal to or lower than the thermo-off temperature Tg1 during the cooling operation (ST4). If the room temperature Ti is not equal to or higher than the thermo-off temperature Tg1 or equal to or lower than the thermo-off temperature Tg1 (ST4-No), the CPU 110 captures whether the captured room temperature Ti is equal to or lower than the thermo-on temperature Tg2 during the heating operation. It is determined whether or not the room temperature Ti is equal to or higher than the thermo-on temperature Tg2 (ST11).

  If the room temperature Ti is equal to or lower than the thermo-on temperature Tg2 or equal to or higher than the thermo-on temperature Tg2 (ST11-Yes), the CPU 110 instructs the outdoor unit 2 to increase the compressor operating capacity C (ST14), and returns the process to ST2. Specifically, the CPU 110 extracts a rotation speed code corresponding to the temperature difference between the current room temperature Ti and the set temperature Tg from the rotation speed table, and transmits a drive instruction signal for the compressor 21 based on the code to the communication unit 130. To the outdoor unit 2.

  If the room temperature Ti is not equal to or lower than the thermo-on temperature Tg2 or equal to or higher than the thermo-on temperature Tg2 (ST11-No), the CPU 110 determines whether or not the current compressor operating capacity C is the minimum operating capacity Cmin (ST12). Note that the CPU 110 indicates that the current compressor operating capacity C is the minimum operating capacity Cmin, and the rotational speed code instructing the outdoor unit 2 is the lowest rotational speed code in the rotational speed table. Judge by whether or not.

  If the current compressor operating capacity C is not the minimum operating capacity Cmin (ST12-No), the CPU 110 returns the process to ST3 and decreases the compressor operating capacity C. As described above, the compressor operating capacity C may be reduced by reducing the rotation speed code of the compressor 21 by one step per unit time (for example, every minute), or by increasing the room temperature change rate Tir. Accordingly, the rotation speed code may be decreased by a plurality of stages per unit time.

  If the current compressor operating capacity C is the minimum operating capacity Cmin (ST12-Yes), the CPU 110 maintains the minimum operating capacity Cmin that is the current compressor operating capacity C (ST13), and returns the process to ST4.

  If the room temperature Ti is equal to or higher than the thermo-off temperature Tg1 or equal to or lower than the thermo-off temperature Tg1 in ST4 (ST4-Yes), the CPU 110 determines whether or not the current compressor operating capacity C is the minimum operating capacity Cmin ( ST5).

  If the current compressor operating capacity C is the minimum operating capacity Cmin (ST5-Yes), the CPU 110 advances the process to ST8. If the current compressor operating capacity C is not the minimum operating capacity Cmin (ST5-No), the CPU 110 stores the room temperature change rate Tir immediately before the room temperature Ti becomes equal to or higher than the thermo-off temperature Tg1 or equal to or lower than the thermo-off temperature Tg1 in ST4. Read from 120 (ST6). The room temperature change rate Tir is the room temperature Ti fetched from the present time and the room temperature fetched immediately before the present time when the room temperature Ti is periodically taken from the room temperature sensor 79 and stored in the storage unit 120 in time series. Calculated using Ti and stored in the storage unit 120.

  Next, the CPU 110 determines whether or not the read room temperature change rate Tir is equal to or higher than a threshold change rate Ts defined in the thermo-off operation table 200 (ST7). If the room temperature change rate Tir is not equal to or greater than the threshold change rate Ts (ST7-No), the CPU 110 returns the process to ST3 and decreases the compressor operating capacity C. If room temperature change rate Tir is more than threshold change rate Ts (ST7-Yes), CPU110 will advance a process to ST8.

  In ST8, the CPU 110 stops the indoor fan 32 and instructs the outdoor unit 2 to stop the compressor 21 via the communication unit 130 (ST8), that is, the air conditioner 1 is put into a thermo-off state.

  When the CPU 110 performs the processes from ST5 to ST8 described above, the process is performed with reference to the above-described thermo-off operation table 200.

  Next, the CPU 110 determines whether or not the captured room temperature Ti is equal to or lower than the thermo-on temperature Tg2 during the heating operation, and whether or not the captured room temperature Ti is equal to or higher than the thermo-on temperature Tg2 during the cooling operation (ST9). If the room temperature Ti is not below the thermo-on temperature Tg2 or above the thermo-on temperature Tg2 (ST9-No), the CPU 110 returns to ST9 and maintains the state where the indoor fan 32 and the compressor 21 are stopped.

  If the room temperature Ti is equal to or lower than the thermo-on temperature Tg2 or equal to or higher than the thermo-on temperature Tg2 (ST9-Yes), the CPU 110 restarts the indoor fan 32 and restarts the compressor 21 with respect to the outdoor unit 2. Instruction is given via 130 (ST10). The CPU 110 extracts a rotation speed code corresponding to the temperature difference between the current room temperature Ti and the set temperature Tg from the rotation speed table, and outputs a drive instruction signal for the compressor 21 based on the code through the communication unit 130. Transmit to machine 2. And the outdoor unit 2 restarts the compressor 21 with the rotation speed according to the received drive instruction signal.

  As described above, when the room temperature Ti reaches the thermo-off temperature Tg1, the air conditioner 1 of the present invention first enters the thermo-off state when the compressor operating capacity C is the minimum operating capacity Cmin, and the compressor operating capacity is When C is not the minimum operating capacity Cmin, if the room temperature change rate Tir is equal to or greater than the threshold change rate Ts, the thermo-off state is set. The fan 32 continues to drive. Thereby, when there exists a possibility that energy-saving property may deteriorate because the air conditioner 1 continues to operate in a state where the room temperature Ti greatly exceeds the thermo-off temperature Tg1, it is possible to quickly improve the energy-saving property as a thermo-off state. . In addition, when the air conditioner 1 does not continue to operate in a state where the room temperature Ti greatly exceeds the thermo-off temperature Tg1, the operating capacity of the compressor 21 is reduced and the compressor 21 is continuously driven without entering the thermo-off state. In addition, the user's comfort can be improved by continuing to drive the indoor fan 32.

  The minimum operating capacity Cmin in the above-described embodiment has been described as the compressor operating capacity C when the compressor 21 is driven at the rotational speed corresponding to the minimum rotational speed code 1 in the rotational speed table. However, the present invention is not limited to this, and the lower limit operating capacity of the compressor 21 determined when performing control related to the pressure, temperature, etc. of the refrigerant circuit 10 may be the minimum operating capacity Cmin of the present invention.

  For example, if the compressor 21 is driven with a low operating capacity at a low outside air temperature (0 ° C. or less), the refrigerant may stagnate in the refrigerating machine oil of the compressor 21. There is a possibility that the compressor oil is exhausted and the refrigerator oil is exhausted. In such a case, it is desirable to increase the operating capacity of the compressor 21 as much as possible to raise the temperature inside the compressor 21. Accordingly, the lower limit operating capacity of the compressor 21 when the control for suppressing the refrigerant stagnation is performed is larger than the compressor operating capacity C corresponding to the minimum engine speed code defined in the engine speed table described above. Is desirable.

  In the above case, control related to the thermo-off of the present invention is performed with the operating capacity larger than the compressor operating capacity C corresponding to the minimum rotation speed code as the minimum operating capacity Cmin of the air conditioner 1. Further, normally, when the control related to the thermo-off is performed with the compressor operating capacity C corresponding to the minimum rotation speed code as the minimum operating capacity Cmin, and the control related to the refrigerant circuit 10 is performed, the lower limit operating capacity determined by the control is minimized. As the operating capacity Cmin, the larger operating capacity may be appropriately set as the minimum operating capacity Cmin.

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Outdoor unit 3 Indoor unit 10 Refrigerant circuit 21 Compressor 22 Four way valve 23 Outdoor heat exchanger 31 Indoor heat exchanger 32 Indoor fan 76 Outside temperature sensor 79 Room temperature sensor 100 Outdoor unit control part 110 CPU
120 Storage unit 130 Communication unit 140 Sensor input unit 200 Thermo-off operation table C Compressor operating capacity Cmin Minimum operating capacity Ti Room temperature ΔTi Room temperature change rate Tg Set temperature Tg1 Thermo-off temperature Tg2 Thermo-on temperature Ts Threshold change rate

Claims (4)

An outdoor unit having a compressor capable of changing the operating capacity;
An indoor heat exchanger, an indoor fan, and an indoor unit having a room temperature sensor for detecting room temperature,
A refrigerant circuit formed by connecting the outdoor unit and the indoor unit with a refrigerant pipe;
Control means for periodically taking in the room temperature detected by the room temperature sensor and controlling the driving of the compressor and the indoor fan;
An air conditioner having
The control means includes
Calculate the room temperature change rate, which is the time change rate of the captured room temperature,
When the captured room temperature reaches a predetermined thermo-off temperature,
If the operating capacity of the compressor is the minimum operating capacity, stop the compressor and the indoor fan,
If the operating capacity of the compressor is not the minimum operating capacity,
If the room temperature change rate calculated immediately before the room temperature reaches the thermo-off temperature is equal to or higher than a predetermined threshold change rate, the compressor and the indoor fan are stopped,
If the room temperature change rate calculated immediately before the room temperature reaches the thermo-off temperature is less than a predetermined threshold change rate, the operating capacity of the compressor is reduced.
An air conditioner characterized by that. The minimum operating capacity is an operating capacity corresponding to a predetermined minimum rotational speed of the compressor;
The air conditioner according to claim 1. The minimum operating capacity is an operating capacity determined in accordance with the control of the refrigerant circuit, separately from the predetermined minimum rotational speed of the compressor.
The air conditioner according to claim 1. The minimum operating capacity is an operating capacity corresponding to a predetermined minimum rotational speed of the compressor, or a larger operating capacity among operating capacity determined according to control of the refrigerant circuit,
The air conditioner according to any one of claims 1 to 3.

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