JP5423150B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner.

2. Description of the Related Art Conventionally, an air conditioner that calculates a control air conditioning load and controls the rotational speed of a compressor that correlates with the air conditioning capability (output) based on the air conditioning load is known.
For example, in the air conditioner of Patent Document 1, the air conditioning load on control is calculated as “the difference between the indoor intake air temperature and the indoor set temperature”, and the value corresponds to one of a plurality of predetermined temperature ranges. Thus, it has been proposed to change the upper limit frequency of the drive frequency (rotational speed) of the compressor stepwise. For example, when the air conditioning load belongs to the largest region among preset temperature regions, the upper limit frequency of the compressor is increased. As a result, the air conditioning capability, that is, the hunting width of the actual drive frequency of the compressor can be suppressed, and as a result, the number of thermo-offs and thermo-ons can be reduced, and energy saving can be improved.

  Further, in the air conditioner of Patent Document 2, the control air conditioning load is calculated as “difference between room temperature and remote control set temperature”, and the compressor operating frequency (rotational speed) is set in advance by the air conditioning load. It has been proposed to make a determination by applying to frequency allocation conditions. As frequency allocation conditions, two types (high load allocation conditions and low load allocation conditions) that can be selected depending on whether the air conditioning load tends to be high or low are provided. The application of the frequency allocation condition is not started immediately after the outdoor unit is started, but after the air conditioning load calculated in the above-described manner falls within a certain value (that is, after entering the stable range). Until then, the operating frequency of the compressor is integrated every minute, and the frequency allocation condition of the above-mentioned high load tendency or low load tendency is properly used depending on the integrated value when the air conditioning load falls within a certain value. ing. Thereby, the optimal air-conditioning capability corresponding to an air-conditioning load can be obtained reliably and promptly, and the comfort and energy saving can be improved.

  Furthermore, in the air conditioner of Patent Document 3, a plurality of compressors such as inverter drives are mounted, and the sum of the differences between the room temperature and the remote controller set temperature (the sum of all indoor units) is used as an air conditioning load for control. It has been proposed to calculate and control the operation frequency (rotational speed) of each compressor in a plurality of patterns according to the air conditioning load. As a result, each compressor is operated at an operation frequency or the like corresponding to the actual air conditioning load, and it is possible to ensure optimum air conditioning capacity and to avoid unnecessary operation stop.

JP 2007-10200 A JP-A-5-346259 JP-A-5-157374

  By the way, in the air conditioning apparatus of patent documents 1-3, since the operation capacity (horsepower) of the indoor unit is not included in the calculation of the control air conditioning load, for example, a space (room) in which only the small capacity indoor unit is installed. ) And the space where large-capacity indoor units are installed, the control air-conditioning load calculated in the above-described manner is the same even though the air-conditioning load is originally different. It will be considered. For this reason, comfort may be hindered especially in a space where a large-capacity indoor unit is installed.

  The objective of this invention is providing the air conditioning apparatus which can improve the comfort in the space in which each indoor unit is installed, improving energy saving.

  In order to solve the above problems, the invention described in claim 1 functions as a compressor that compresses refrigerant as it rotates and a condenser for refrigerant during cooling operation, and as a refrigerant evaporator during heating operation. An air conditioner comprising: an outdoor unit having an outdoor unit heat exchanger; and a plurality of indoor units having an indoor unit heat exchanger that functions as a refrigerant evaporator during cooling operation and functions as a refrigerant condenser during heating operation In the above, the capacity acquisition means for acquiring all the operating capacities of the plurality of indoor units, respectively, and the temperature difference between the actual air temperature and the target air temperature in all the operating of the plurality of indoor units, respectively. Temperature difference acquisition means, and the capacity acquired for each indoor unit, a value obtained by summing up the capacity acquired for each indoor unit and the multiplication value of the temperature difference in all the indoor units. All the above Computation means for computing the air conditioning load temperature difference by dividing by the total value in the internal unit, and rotational speed control means for controlling the upper limit of the rotational speed of the compressor based on the computed air conditioning load temperature difference This is the gist.

  According to this configuration, the capacity (horsepower) of each indoor unit in operation is included in the calculation of the air conditioning load temperature difference as the air conditioning load for control. The upper limit of the rotation speed of the compressor is controlled based on the calculated air conditioning load temperature difference. Therefore, for example, even when a space (room) where only a small-capacity indoor unit is installed and a space where a large-capacity indoor unit is installed are mixed, optimum air conditioning corresponding to the air conditioning load in each indoor unit Capability can be ensured, and comfort in the space where each indoor unit is installed can be improved. Moreover, unnecessary operation stop of the compressor can be avoided, and energy saving can be improved.

Furthermore, the rotational speed control means controls the upper limit of the rotational speed of the compressor based on the air conditioning load upper limit rotational speed that is updated every predetermined period after the establishment of a predetermined condition representing the stable state of the system, Control effect amount calculation means for calculating the control effect amount by subtracting the previous air conditioning load temperature difference from the previous air conditioning load temperature difference calculated by the arithmetic means, and the previous air conditioning load upper limit rotation from the previous air conditioning load upper limit rotation speed. The control amount calculation means that calculates the previous control amount by reducing the speed, and the value obtained by multiplying the previous air conditioning load upper limit rotation speed by the control effect amount multiplied by the current air conditioning load temperature difference It computes the next air conditioning load upper limit rotation speed Ru and a air-conditioning load upper limit rotation speed calculation means.

  According to this configuration, the air conditioning load upper limit rotational speed, which is the upper limit of the rotational speed of the compressor, is calculated by dividing the previous air conditioning load upper limit rotational speed by a value obtained by dividing the previous control amount by the control effect amount. It is calculated by adding the value multiplied by. That is, the next control amount (the value obtained by subtracting the previous air conditioning load upper limit rotation speed from the next air conditioning load upper limit rotation speed) is the previous control amount and the air conditioning load fluctuation amount (control effect amount) when the control amount is given. To be determined. Thus, in calculating the air conditioning load upper limit rotation speed, the control amount and the air conditioning load fluctuation amount (control effect amount) when the control amount is given are reflected, so that the air conditioning load is originally requested. The upper limit of the rotation speed of the compressor can be calculated more accurately, and the air temperature in the space in which each indoor unit is installed is targeted while improving energy saving by suppressing the number of start and stop of the compressor. It can be quickly reached by the air temperature.

According to a second aspect of the present invention, in the air conditioner according to the first aspect , when the calculated air conditioning load temperature difference exceeds a predetermined air conditioning load temperature difference, the compressor of the compressor by the rotational speed control means is provided. The gist of the invention is that a stopping means for stopping the upper limit control of the rotational speed is provided.

  According to this configuration, for example, the control air conditioning load is increased due to an increase in the operating capacity accompanying an increase in the outside air temperature during cooling operation, a decrease in the outside air temperature during heating operation, or an increase in the number of indoor units during operation. When a certain air conditioning load temperature difference exceeds a predetermined air conditioning load temperature difference, the upper limit control of the rotation speed of the compressor based on the air conditioning load temperature difference is stopped by the stopping means. Therefore, it is possible to prevent the rotation speed of the compressor, that is, the air conditioning capability, from being lowered suddenly in a state where the air conditioning load is high, and it is possible to maintain comfort in the space where each indoor unit is installed. .

A third aspect of the present invention is the air conditioner according to the second aspect , further comprising a low-side pressure sensor and a high-side pressure sensor that respectively detect a pressure of a suction pipe and a pressure of a discharge pipe of the compressor, The stopping means is configured to rotate when the pressure of the suction pipe exceeds a low-side predetermined pressure during cooling operation, or when the pressure of the discharge pipe falls below a high-side predetermined pressure during heating operation. The gist is to stop the upper limit control of the rotational speed of the compressor by the speed control means.

  According to the same configuration, for example, in the cooling operation, when the pressure of the suction pipe exceeds the low side predetermined pressure due to an increase in the operating capacity accompanying an increase in the outside air temperature or an increase in the number of indoor units during operation, that is, In a state where the evaporation temperature of the refrigerant correlated with the pressure is high and the air conditioning load (cooling load) is high, the upper limit control of the rotation speed of the compressor is stopped by the stop means. Similarly, during heating operation, when the discharge pipe pressure falls below the high-side predetermined pressure due to a decrease in outside air temperature or an increase in operating capacity accompanying an increase in the number of indoor units during operation, etc. In a state where the condensation temperature of the refrigerant to be performed is low and the air conditioning load (heating load) is high, the upper limit control of the rotation speed of the compressor is stopped by the stop means. Therefore, it is possible to prevent the rotation speed of the compressor, that is, the air conditioning capability, from being lowered suddenly in a state where the air conditioning load is high, and it is possible to maintain comfort in the space where each indoor unit is installed. .

  In the present invention, it is possible to provide an air conditioner that can improve comfort in a space where each indoor unit is installed while improving energy saving.

The refrigerant circuit diagram which shows one Embodiment of this invention. The graph which shows the relationship between the temperature and pressure at the time of condensation or evaporation. The flowchart which shows the control aspect of the embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram showing a heat pump type air conditioner 1 according to the present embodiment. As shown in the figure, the air conditioner 1 includes an outdoor unit 10 and a plurality of indoor units 30. Note that the capacity of each of the plurality of indoor units 30 is selected and set according to the size of the space (room) in which they are installed, and the capacity of at least one indoor unit 30 is that of the other indoor units 30. It may be different from the capacity.

  The outdoor unit 10 is provided with a compressor 12 that compresses the refrigerant as it rotates. The compressor 12 compresses the refrigerant sucked from the suction pipe 12a and sends the refrigerant to a four-way valve 14 connected to the discharge pipe 12b via the refrigerant pipe 13a. The four-way valve 14 is connected to the outdoor unit heat exchanger 15 through the refrigerant pipe 13b, and is connected to each indoor unit 30 (indoor unit heat exchanger 31) through the refrigerant pipe 13d. The four-way valve 14 is connected to an accumulator 18 through a refrigerant pipe 13f, and the accumulator 18 is connected to the suction pipe 12a of the compressor 12 through a refrigerant pipe 13g.

  The outdoor unit heat exchanger 15 functions as a refrigerant condenser during cooling operation and functions as a refrigerant evaporator during heating operation, and is connected to the indoor unit 30 (electronic expansion valve 32) via the refrigerant pipe 13h. It is connected. A check valve 21 that allows the refrigerant to flow toward the indoor unit 30 is disposed in the refrigerant pipe 13h, and an electronic expansion valve 22 is disposed in parallel with the check valve 21.

  The indoor unit heat exchanger 31 installed in each indoor unit 30 is connected to the refrigerant pipe 13d and to the electronic expansion valve 32. The electronic expansion valve 32 is connected to the refrigerant pipe 13h. The indoor unit heat exchanger 31 functions as a refrigerant evaporator during cooling operation and functions as a refrigerant condenser during heating operation.

Next, the operation | movement which concerns on the air conditioning of the air conditioning apparatus 1 is demonstrated. In addition, the flow of the refrigerant | coolant at the time of each operation | movement of cooling and heating is represented by the solid line arrow and the broken line arrow.
First, during the cooling operation, the refrigerant that has exited the discharge pipe 12b of the compressor 12 passes through the four-way valve 14, and is then guided to the outdoor unit heat exchanger 15 that functions as a condenser. In the outdoor unit heat exchanger 15, the refrigerant is deprived of heat by outdoor air (outside air), and condensed and liquefied. Thereafter, the refrigerant guided to the indoor unit 30 via the check valve 21 is depressurized by the electronic expansion valve 32, and in the indoor unit heat exchanger 31 functioning as an evaporator, the heat of the indoor air is taken and vaporized. To do. Thereafter, the refrigerant returns to the suction pipe 12 a of the compressor 12 through the four-way valve 14 and the accumulator 18. Through the above process, the room is cooled.

  On the other hand, during the heating operation, the refrigerant that has exited the discharge pipe 12 b of the compressor 12 passes through the four-way valve 14 and is then guided to the indoor unit 30. The refrigerant releases heat into the indoor air in the indoor unit heat exchanger 31 functioning as a condenser, and condenses and liquefies. Thereafter, the refrigerant decompressed by the electronic expansion valve 32 is further decompressed by the electronic expansion valve 22 and guided to the outdoor unit heat exchanger 15. The refrigerant absorbs and vaporizes the heat of the outdoor air in the outdoor unit heat exchanger 15 that functions as an evaporator. Thereafter, the refrigerant from the outdoor unit heat exchanger 15 through the four-way valve 14 returns to the suction pipe 12 a of the compressor 12 through the accumulator 18. Through the above process, the room is heated.

  Here, the outdoor unit 10 is provided with a control device 41 for driving and controlling the compressor 12 and the like. The control device 41 is mainly composed of a microcomputer, and includes a low side pressure sensor 42 for detecting the refrigerant pressure PL of the suction pipe 12a and a high side pressure sensor 43 for detecting the refrigerant pressure PH of the discharge pipe 12b. Electrically connected.

  On the other hand, each indoor unit 30 is provided with a control device 46 that drives and controls the electronic expansion valve 32 and the like. The control device 46 is mainly composed of a microcomputer, and is electrically connected to a temperature sensor 47 that detects a suction temperature Ts as an air temperature of the indoor unit 30. Further, the control device 46 sets the temperature adjustment set temperature (set temperature of the operation panel, remote controller, etc.) Tm as the target air temperature set for the indoor unit 30 and the capacity (horsepower) PW of the indoor unit 30. Store in the built-in storage means.

  And the control apparatus 41 is comprised so that the suction temperature Ts of each indoor unit 30 under operation, setting temperature Tm, capacity | capacitance PW, etc. can be acquired through a suitable communication means (a capacity | capacitance acquisition means, a temperature difference acquisition means), Based on the suction temperature Ts, the set temperature Tm, and the capacity PW, the air conditioning load of the entire apparatus (the air conditioning load totaled by all the indoor units 30) is calculated (calculation means). And the control apparatus 41 controls the upper limit of the rotational speed of the compressor 12 based on the air-conditioning load of the whole apparatus, for example (rotational speed control means). This control (hereinafter also referred to as “air conditioning load upper limit rotational speed control”) is for reducing the rotational speed of the compressor 12 for the purpose of improving energy saving.

  Alternatively, the control device 41 controls the rotational speed of the compressor 12 based on the required rotational speed based on the refrigerant pressure PL of the suction pipe 12a during the cooling operation (hereinafter also referred to as “cooling evaporation pressure request control”). During the heating operation, the rotation speed of the compressor 12 is controlled based on the required rotation speed based on the refrigerant pressure PH of the discharge pipe 12b (hereinafter also referred to as “condensing pressure request control during heating”). When the cooling evaporation pressure request control or the heating condensing pressure request control (hereinafter also referred to as “required rotation speed control”) is performed, the use region maximum rotation speed Nmax is set as the upper limit rotation speed of the compressor 12. . This use region maximum rotation speed Nmax is a standard (system) upper limit rotation speed that can avoid, for example, abnormal overheating of the control device 41 or the like, overload operation of the compressor 12, and the like. Therefore, when the required rotational speed control is performed, the rotational speed of the compressor 12, that is, the air conditioning capability is sufficiently ensured, and the comfort in the space where each indoor unit 30 is installed is quickly improved.

  Here, the rotational speed control mode of the compressor 12 during the cooling operation by the control device 41 will be described more specifically. When the outdoor unit 10 (compressor 12) is started by turning on the operation panel of the indoor unit 30 or the remote controller, the control device 41 performs the above-described required rotational speed control (cooling evaporation pressure request control) of the compressor 12. And if predetermined time (for example, 5 minutes) or more passes after starting the outdoor unit 10, the control apparatus 41 will start the calculation of air-conditioning load temperature difference (DELTA) Ts according to the following Formula (1). That is, the control device 41 does not calculate the air conditioning load temperature difference ΔTs by continuing the required rotation speed control until the predetermined time or more has elapsed since the outdoor unit 10 was started. This is to keep the system at least stable prior to the upper limit control of the rotational speed of the compressor 12 described above.

Air-conditioning load temperature difference ΔTs = (the value of (capacity PW × (suction temperature Ts−set temperature Tm)) of all the indoor units 30 in operation) / (each indoor unit 30 in operation) (The total value of the capacity PW of the unit 30 for all indoor units 30 in operation)
... (1)
The air conditioning load temperature difference ΔTs calculated in this way includes the capacity PW of each indoor unit 30 in operation. The control device 41 determines that the air conditioning load temperature difference ΔTs is less than a predetermined temperature difference DTc (for example, 2 ° C.) and the refrigerant evaporation temperature VT is lower than the predetermined temperature VTc (for example, 6 ° C.). Start air conditioning load upper limit rotation speed control. As shown in FIG. 2, the evaporation temperature VT correlates with the refrigerant pressure PL (evaporation pressure) of the suction pipe 12a and is detected by the low-side pressure sensor.

  That is, the control device 41 does not operate the compressor 12 in the operation region where the air conditioning load temperature difference ΔTs is large and the air conditioning load as a whole device is large even after the predetermined time has elapsed since the outdoor unit 10 is started. The air conditioning load upper limit rotational speed control is not started (standby) because there is no need to lower the rotational speed. Alternatively, the control device 41, in the operation region where the refrigerant evaporating temperature VT is high and the blowout temperature of the indoor unit 30 as a whole device is high even after the predetermined time has elapsed since the outdoor unit 10 was started, Lowering the rotational speed of the compressor 12 further increases the evaporation temperature VT, and the blowout temperature of the indoor unit 30 may rise to impair comfort. Therefore, the air conditioning load upper limit rotational speed control is not started (standby). ).

  When it is determined that the system is stable, the air conditioning load of the entire apparatus is reduced, and there is no possibility of impairing comfort, the control device 41 starts the air conditioning load upper limit rotational speed control. That is, the control device 41 gives a value obtained by multiplying the current rotational speed of the compressor 12 by “0.9” as the initial rotational speed (initial value) of the control. Then, the control device 41 waits until a predetermined time T (for example, 30 seconds), which is a rotation speed control cycle, has elapsed after performing the upper limit control of the rotation speed of the compressor 12 at the initial rotation speed. At the next control cycle after the predetermined time T has elapsed, the control device 41 calculates the air conditioning load upper limit rotational speed N according to the following equation (2) based on the control amount ΔN and the control effect amount E (air conditioning load upper limit rotational speed calculating means, Control effect amount calculation means, control amount calculation means).

Air conditioning load upper limit rotational speed N (i) = previous air conditioning load upper limit rotational speed N (i−1) + (previous control amount ΔN (i−1) / control effect amount E (i)) × air conditioning load temperature difference ΔTs ( i)
(I is the number of control cycles)
However,
Previous control amount ΔN (i−1) = previous air conditioning load upper limit rotational speed N (i−1) −previous air conditioning load upper limit rotational speed N (i−2)
Control effect amount E (i) = previous air conditioning load temperature difference ΔTs (i−2) −previous air conditioning load temperature difference ΔTs (i−1)
... (2)
At the start of the air conditioning load upper limit rotational speed control, when a value obtained by multiplying the rotational speed of the compressor 12 by “0.9” is given as the initial rotational speed, the rotational speed of the compressor 12 is set as the initial value of the previous control amount. A value obtained by multiplying by “0.1” is adopted.

  That is, the next control amount ΔN (i) (= the air conditioning load upper limit rotational speed N (i) −the previous air conditioning load upper limit rotational speed N (i−1)) for lowering the rotational speed of the compressor 12 is the previous control. It is determined based on the air conditioning load fluctuation amount (control effect amount E (i)) when the amount ΔN (i-1) and the control amount ΔN (i-1) are given. Thus, in calculating the air conditioning load upper limit rotational speed, the compression amount originally requested from the air conditioning load is reflected by reflecting the previous control amount and the air conditioning load fluctuation amount (control effect amount) when the control amount is given. The upper limit of the rotational speed of the machine 12 is calculated more accurately.

Thereafter, the control device 41 repeats the same control (air conditioning load upper limit rotational speed control) every time the predetermined time T elapses.
In addition, when the air conditioning load upper limit rotational speed control is repeated in the above-described manner, if the air conditioning load increases due to an increase in operating capacity due to an increase in the outside air temperature or an increase in the number of indoor units during operation, etc. Since the apparatus 41 needs to increase the rotational speed of the compressor 12 again, it stops the air conditioning load upper limit rotational speed control (stopping means), and performs the above-mentioned required rotational speed control (cooling evaporation pressure request control). Resume.

  Specifically, the control device 41 determines that the air conditioning load temperature difference ΔTs is equal to or greater than a predetermined temperature difference DTc1 (for example, 3 ° C.) as the predetermined air conditioning load temperature difference, or the refrigerant pressure PL of the suction pipe 12a is the low side predetermined pressure. If the refrigerant evaporating temperature VT, which correlates with the temperature exceeds a predetermined temperature VTc1 (for example, 10 ° C.), the air-conditioning load upper limit rotational speed control is stopped and the required rotational speed control is restarted. Thereby, it is possible to prevent the rotational speed of the compressor 12 from being lowered in an operation region where the air conditioning load temperature difference ΔTs is large and the air conditioning load of the entire apparatus can be considered large. Alternatively, it is possible to prevent the rotational speed of the compressor 12 from being lowered in an operation region where the evaporation temperature VT of the refrigerant is high and the blowout temperature of the indoor unit 30 as the whole apparatus is high, and the blowout of the indoor unit 30 can be prevented. The possibility that the temperature rises and the comfort is impaired can be reduced. In order to avoid a sudden increase in the rotational speed of the compressor 12 when switching from the air conditioning load upper limit rotational speed control to the required rotational speed control, it is more preferable to gradually increase the upper limit of the rotational speed.

  Next, the rotation speed control mode of the compressor 12 during the heating operation by the control device 41 will be described. Since the above control during the heating operation is basically performed according to the above-described cooling operation, only differences from the cooling operation are extracted and described here.

  When the outdoor unit 10 is started, the control device 41 performs the above-described required rotational speed control (heating-time condensation pressure request control) of the compressor 12. And if predetermined time (for example, 5 minutes) or more passes after starting the outdoor unit 10, the control apparatus 41 will start the calculation of air-conditioning load temperature difference (DELTA) Ts according to the following Formula (3).

Air-conditioning load temperature difference ΔTs = (the value of (capacity PW × (set temperature Tm−suction temperature Ts)) of all operating indoor units 30 for all the operating indoor units 30) ÷ (each operating room (The total value of the capacity PW of the unit 30 for all indoor units 30 in operation)
... (3)
The control device 41 determines that the air conditioning load temperature difference ΔTs is less than a predetermined temperature difference DTh (for example, 2 ° C.) and the refrigerant condensing temperature CT is equal to or higher than the predetermined temperature CTh (for example, 40 ° C.). The air conditioning load upper limit rotation speed control is started. As shown in FIG. 2, the condensation temperature CT correlates with the pressure (condensation pressure) of the discharge pipe 12 b and is detected by the high-side pressure sensor 43.

  When it is determined that the system is stable, the air conditioning load of the entire apparatus is reduced, and there is no possibility of impairing comfort, the control device 41 starts the air conditioning load upper limit rotational speed control. At this time, the control device 41 calculates the air conditioning load upper limit rotation speed N by applying the air conditioning load temperature difference ΔTs calculated based on the expression (3) to the expression (2) (air conditioning load upper limit rotation speed calculating means, Control effect amount calculation means, control amount calculation means). When calculating the air conditioning load upper limit rotational speed, the control amount of the compressor 12 that is originally requested by the air conditioning load is reflected by reflecting the previous control amount and the air conditioning load fluctuation amount (control effect amount) when the control amount is given. As described above, the upper limit of speed is calculated more accurately.

  When the air conditioning load upper limit rotational speed control is repeated at every elapse of the predetermined time T, if the air conditioning load increases due to an increase in operating capacity due to a decrease in the outside air temperature or an increase in the number of indoor units during operation, Since the control device 41 needs to increase the rotational speed of the compressor 12 again, the control device 41 stops the air conditioning load upper limit rotational speed control (stop means), and the above-mentioned required rotational speed control (heating condensation pressure request control). To resume. Specifically, in the control device 41, the air conditioning load temperature difference ΔTs is equal to or greater than a predetermined temperature difference DTh1 (for example, 3 ° C.), or the refrigerant pressure PH of the discharge pipe 12b exceeds the predetermined high pressure and correlates with this. When the refrigerant condensing temperature CT falls below a predetermined temperature CTh1 (for example, 35 ° C.), the air conditioning load upper limit rotational speed control is stopped and the required rotational speed control is resumed. Thereby, it is possible to prevent the rotational speed of the compressor 12 from being lowered in an operation region where the air conditioning load temperature difference ΔTs is large and the air conditioning load of the entire apparatus can be considered large. Alternatively, it is possible to prevent the rotation speed of the compressor 12 from being lowered in an operation region where the refrigerant condensing temperature CT is low and the blowing temperature of the indoor unit 30 as a whole apparatus can be regarded as low. It is possible to reduce the possibility that the temperature decreases and the comfort is impaired.

  Next, the rotational speed control mode of the compressor 12 during the cooling operation by the control device 41 will be described based on the flowchart of FIG. When the process shifts to this routine due to the operation panel of the indoor unit 30 or the remote control being turned on, the outdoor unit 10 is started (S1). Then, the required rotational speed control (cooling evaporation pressure request control) of the compressor 12 is performed (S2). Subsequently, after the outdoor unit 10 is started, the elapse of the predetermined time or more is waited (S3), and the calculation of the air conditioning load temperature difference ΔTs is started according to the equation (1), and the air conditioning load temperature difference ΔTs is It is determined whether or not the temperature difference is less than the predetermined temperature difference DTc (S4). Then, after it is determined that the air conditioning load temperature difference ΔTs is less than the predetermined temperature difference DTc, it is determined whether or not the refrigerant evaporation temperature VT is lower than the predetermined temperature VTc (S5).

  Subsequently, after the evaporating temperature VT of the refrigerant is determined to be lower than the predetermined temperature VTc, the calculation of the air conditioning load upper limit rotational speed is started (S6). That is, a value obtained by multiplying the current rotational speed of the compressor 12 by “0.9” is set as the initial rotational speed of the control (S7). Then, after the air conditioning load upper limit rotational speed control is performed at this initial rotational speed, the passage of the predetermined time T or longer is waited (S8), and the air conditioning load upper limit rotational speed N is calculated according to the equation (2) (S9). .

  Next, it is determined whether or not the air conditioning load temperature difference ΔTs is equal to or greater than the predetermined temperature difference DTc1 (S10). Here, if it is determined that the air conditioning load temperature difference ΔTs is less than the predetermined temperature difference DTc1, it is further determined whether or not the refrigerant evaporation temperature VT is equal to or higher than the predetermined temperature VTc1 (S11). If it is determined that the refrigerant evaporation temperature VT is lower than the predetermined temperature VTc1, the process returns to S8 and the same control (air conditioning load upper limit rotational speed control) is repeated. That is, after the air conditioning load upper limit rotational speed control is performed with the air conditioning load upper limit rotational speed N updated / set in S9, the next air conditioning load upper limit rotational speed N is calculated after waiting for the predetermined time T or more. .

  If the air conditioning load temperature difference ΔTs is determined to be equal to or greater than the predetermined temperature difference DTc1 in S10, or the refrigerant evaporation temperature VT is determined to be equal to or greater than the predetermined temperature VTc1, the calculation of the air conditioning load upper limit rotational speed is stopped ( S12). Then, the above-described required rotation speed control (cooling evaporation pressure request control) is performed in which the upper limit rotation speed of the compressor 12 is set to the maximum use area rotation speed.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) In this embodiment, the capacity PW of each indoor unit 30 during operation is included in the calculation of the air conditioning load temperature difference ΔTs as the air conditioning load for control. The upper limit of the rotational speed of the compressor 12 is controlled based on the air conditioning load temperature difference ΔTs. Therefore, for example, when a space (room) where only small-capacity indoor units are installed and a space where large-capacity indoor units are installed are mixed (when different-capacity indoor units are connected in a multi-system for buildings, etc.) ), It is possible to ensure the optimum air conditioning capacity corresponding to the air conditioning load in each indoor unit 30 and to improve the comfort in the space in which each indoor unit 30 is installed.

  That is, for example, there are a space where only a large capacity indoor unit is installed (A space) and a space where only a small capacity indoor unit is installed (B space), and the difference between the set temperature of the A space and the room temperature is 2 °. Consider a case where the difference between the set temperature of the B space and the room temperature does not change from C but changes from 2 ° C to 0 ° C. If the control air conditioning load is simply calculated as “difference between set temperature and room temperature” or “total difference between set temperature and room temperature”, it is considered that the control air conditioning load is decreasing. The rotational speed of the compressor 12 will be lowered. On the other hand, in this embodiment, since the indoor temperature of the A space remains unchanged from the set temperature, the air conditioning load temperature difference ΔTs as the control air conditioning load remains large. Accordingly, an excessive decrease in the rotational speed of the compressor 12 can be suppressed, and the rotational speed of the compressor 12 can be controlled with the originally required operating capacity. Further, unnecessary operation stop of the compressor 12 can be avoided, and energy saving can be improved.

  (2) In the present embodiment, the air conditioning load upper limit rotational speed N (i) that is the upper limit of the rotational speed of the compressor 12 is set to the previous control amount ΔN (i) to the previous air conditioning load upper limit rotational speed N (i−1). It is calculated by adding a value obtained by multiplying the value obtained by dividing -1) by the control effect amount E (i) by the current air conditioning load temperature difference ΔTs (i). That is, the next control amount ΔN (a value obtained by subtracting the previous air conditioning load upper limit rotational speed N (i−1) from the next air conditioning load upper limit rotational speed N (i)) is the previous control amount ΔN (i−1). It is determined based on the air conditioning load fluctuation amount (control effect amount E (i)) when the control amount ΔN (i−1) is given. Thus, in calculating the air conditioning load upper limit rotational speed N (i), the air conditioning load fluctuation amount (control effect amount E when the previous control amount ΔN (i−1) and the control amount ΔN (i−1) are given. By reflecting (i)), the upper limit of the rotational speed of the compressor 12 originally required from the air conditioning load can be calculated more accurately, and energy saving is achieved by suppressing the number of times the compressor 12 is started and stopped. The suction temperature Ts of the space in which each indoor unit 30 is installed can be quickly reached by the set temperature Tm while improving the temperature.

  That is, for example, if the rotational speed of the compressor 12 is lowered while the difference between the suction temperature Ts and the set temperature Tm is 2 ° C., and the same rotational speed is given during the next control, the air conditioning load decreases. Since the rotational speed of the compressor 12 is not fluctuated during a certain temperature region, the followability to the set temperature Tm is deteriorated, and the number of start / stop operations may not be suppressed. On the other hand, in the present embodiment, the influence of the control fluctuation range (control amount) given from the air conditioning load on the air conditioning load fluctuation amount (control effect amount) is considered, and the difference between the suction temperature Ts and the set temperature Tm ( By calculating the next control fluctuation range based on the air conditioning load temperature difference ΔTs), it is possible to improve the followability up to the set temperature Tm and to suppress the number of start / stop times.

  (3) In the present embodiment, for example, the control air conditioning is performed due to an increase in the operating capacity accompanying an increase in the outside air temperature during the cooling operation, a decrease in the outside air temperature during the heating operation, or an increase in the number of indoor units during operation. When the air conditioning load temperature difference ΔTs, which is a load, exceeds the predetermined temperature differences DTc1, DTh1, the upper limit control of the rotational speed of the compressor 12 based on the air conditioning load temperature difference ΔTs is stopped. Therefore, it is possible to prevent the rotational speed of the compressor 12, that is, the air conditioning capability, from being lowered suddenly under a high air conditioning load, and to maintain comfort in the space where each indoor unit 30 is installed. it can.

  (4) In the present embodiment, for example, during the cooling operation, the refrigerant pressure PL of the suction pipe 12a decreases to a predetermined value on the low side due to an increase in the operating capacity accompanying an increase in the outside air temperature or an increase in the number of indoor units during operation. If the refrigerant evaporating temperature VT correlated with the refrigerant pressure PL exceeds the predetermined temperature VTc1 and the air conditioning load (cooling load) is high, the upper limit of the rotational speed of the compressor 12 based on the air conditioning load temperature difference ΔTs. Control is stopped. Similarly, during the heating operation, when the refrigerant pressure PH of the discharge pipe 12b falls below the high-side predetermined pressure due to a decrease in the outside air temperature or an increase in the operating capacity accompanying an increase in the number of indoor units during operation, that is, the refrigerant When the refrigerant condensation temperature CT correlated with the pressure PH exceeds the predetermined temperature CTh1 and the air conditioning load (heating load) is high, the upper limit control of the rotational speed of the compressor 12 based on the air conditioning load temperature difference ΔTs is stopped. Therefore, it is possible to prevent the rotational speed of the compressor 12, that is, the air conditioning capability, from being lowered suddenly under a high air conditioning load, and to maintain comfort in the space where each indoor unit 30 is installed. it can.

  (5) In the present embodiment, when the upper limit control of the rotational speed of the compressor 12 based on the air conditioning load temperature difference ΔTs is stopped, the request based on the refrigerant pressure PL (evaporation pressure) of the suction pipe 12a during the cooling operation. Based on the rotational speed, during the heating operation, the rotational speed of the compressor 12 is controlled based on the required rotational speed based on the refrigerant pressure PH (condensation pressure) of the discharge pipe 12b. The air conditioning capability can be suitably secured.

In addition, you may change the said embodiment as follows.
The present invention includes an electric heat pump (EHP) type air conditioner in which the compressor 12 is rotationally driven by an electric motor, a gas heat pump (GHP) type air conditioner in which the compressor 12 is rotationally driven by a gas engine, The present invention may be applied to a kerosene heat pump (KHP) type air conditioner in which the compressor 12 is rotationally driven by a kerosene engine. In each of these cases, the rotational speed of the compressor 12 may be indirectly controlled via the rotational speed of an electric motor, a gas engine, or a kerosene engine.

In particular, when an engine-driven air conditioner is employed, for example, the exhaust heat may be used in conjunction with the engine coolant circuit during heating operation.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

In the air conditioner according to claim 3 , when the upper limit control of the rotation speed of the compressor is stopped by the stop means, the maximum rotation speed in the use region is set as the upper limit, and during the cooling operation, the suction pipe An air conditioner that controls the rotational speed of the compressor based on a required rotational speed based on a pressure, based on a required rotational speed based on a pressure in the discharge pipe during heating operation. According to this configuration, when the upper limit control of the rotation speed of the compressor is stopped, during the cooling operation, based on the required rotation speed based on the pressure (evaporation pressure) of the suction pipe, during the heating operation. Since the rotation speed of the compressor is controlled based on the required rotation speed based on the pressure of the discharge pipe (condensation pressure), the air conditioning capability can be suitably ensured even in a high air conditioning load state.

  DESCRIPTION OF SYMBOLS 1 ... Air conditioning apparatus, 10 ... Outdoor unit, 12 ... Compressor, 12a ... Intake pipe, 12b ... Discharge pipe, 15 ... Outdoor unit heat exchanger, 30 ... Indoor unit, 31 ... Indoor unit heat exchanger, 41 ... Control Apparatus (capacity acquisition means, temperature difference acquisition means, calculation means, rotation speed control means, control effect amount calculation means, control amount calculation means, air conditioning load upper limit rotation speed calculation means, stop means), 42 ... low side pressure sensor, 43 ... High side pressure sensor.

Claims (3)

A compressor that compresses refrigerant as it rotates and an outdoor unit that has an outdoor unit heat exchanger that functions as a refrigerant condenser during cooling operation and a refrigerant evaporator during heating operation, and refrigerant evaporation during cooling operation In an air conditioner comprising a plurality of indoor units having an indoor unit heat exchanger that functions as a condenser and functions as a refrigerant condenser during heating operation,
Capacity acquisition means for respectively acquiring all the capacity during operation among the plurality of indoor units;
A temperature difference acquisition means for acquiring a temperature difference between an actual air temperature and a target air temperature in all of the plurality of indoor units during operation; and
A value obtained by summing the multiplication value of the capacity acquired for each indoor unit and the temperature difference in all the indoor units is used, and the capacity acquired for each indoor unit is calculated for all the indoor units. An arithmetic means for calculating an air conditioning load temperature difference by dividing by the total value;
A rotational speed control means for controlling an upper limit of the rotational speed of the compressor based on the calculated air conditioning load temperature difference ;
The rotational speed control means controls an upper limit of the rotational speed of the compressor based on an air conditioning load upper limit rotational speed that is updated every predetermined period after a predetermined condition representing a stable state of the system is established,
Control effect amount calculating means for calculating the control effect amount by subtracting the previous air conditioning load temperature difference from the previous air conditioning load temperature difference calculated by the calculating means;
A control amount calculation means for calculating the previous control amount by subtracting the previous air conditioning load upper limit rotation speed from the previous air conditioning load upper limit rotation speed;
Calculate the next air conditioning load upper limit rotational speed by adding the previous air conditioning load upper limit rotational speed to the value obtained by dividing the previous control amount by the control effect amount and the current air conditioning load temperature difference to calculate the next air conditioning load upper limit rotational speed. an air conditioning apparatus characterized by comprising a means. In the air conditioning apparatus according to claim 1 ,
Air conditioning characterized by comprising stop means for stopping upper limit control of the rotational speed of the compressor by the rotational speed control means when the calculated air conditioning load temperature difference exceeds a predetermined air conditioning load temperature difference. apparatus. In the air conditioning apparatus according to claim 2 ,
A low-side pressure sensor and a high-side pressure sensor that respectively detect the pressure of the suction pipe and the pressure of the discharge pipe of the compressor;
When the pressure of the suction pipe exceeds the low side predetermined pressure during the cooling operation, and when the pressure of the discharge pipe falls below the high side predetermined pressure during the heating operation, the stop means An air conditioner that stops upper limit control of the rotational speed of the compressor by the rotational speed control means.

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