KR20100129137A - Air conditioner - Google Patents

Abstract

PURPOSE: An air conditioning device is provided to improve comfort in spaces where indoor units are installed and to improve an energy saving effect. CONSTITUTION: An air conditioning device(1) comprises an outdoor unit(10), multiple indoor units(30), a capacity acquisition unit, a temperature difference acquisition unit, a calculation unit, and a rotational speed control unit. The outdoor unit has an outdoor heat exchanger(15). Each indoor unit has an indoor heat exchanger(31). The capacity acquisition unit acquires capacity of the indoor units. The temperature difference acquisition unit acquires a temperature difference between actual air temperature and a target air temperature. The calculation unit calculates an air conditioning temperature difference. The rotational speed control unit control the speed of a compressor based on the calculated air conditioning temperature difference.

Description

Air Conditioning Equipment {AIR CONDITIONER}

The present invention relates to an air conditioner.

Background Art Conventionally, an air conditioner that calculates a control air conditioning load and controls the rotational speed of a compressor that correlates to the air conditioning capacity (output) based on the air conditioning load is known.

For example, in the air conditioner of Patent Literature 1, the control air conditioning load is calculated as the "difference between the indoor suction air temperature and the indoor set temperature", and the value corresponds to one of a plurality of predetermined temperature ranges. It is proposed to change the upper limit frequency of the drive frequency (rotational speed) of the compressor in steps. For example, when the air conditioning load belongs to the largest region among the preset temperature ranges, the upper limit frequency of the compressor is increased. As a result, the air conditioning capacity, i.e., the hunting width of the actual driving frequency of the compressor can be suppressed, and as a result, the number of thermostat off and the number of thermostat on can be reduced. Therefore, improvement of energy saving is aimed at.

In addition, in the air conditioner of Patent Literature 2, the air conditioning load on the control is calculated as the "difference between the room temperature and the remote control set temperature", and the operating frequency (rotation speed) of the compressor is set in advance by the air conditioning load. It is proposed to decide according to. As the frequency allocation conditions, two types (high load allocation conditions and low load allocation conditions) are selectable depending on whether the air conditioning load is a high load tendency or a low load tendency. The application of the frequency assignment condition is not immediately after the outdoor unit is started, but after the air conditioning load calculated in the above-described mode falls within a predetermined value (that is, after entering the stable region). And up to that, the operating frequency of the compressor is accumulated every minute, and the frequency allocation condition of the high load tendency or the low load tendency is classified and used according to the integrated value at the time when the air conditioning load falls within a certain value. have. As a result, the optimum air conditioning capability corresponding to the air conditioning load can be obtained reliably and quickly, and the comfort and energy saving properties are improved.

In addition, the air conditioner of Patent Literature 3 is equipped with a plurality of compressors such as inverter driving, and calculates the sum of the difference between the indoor temperature and the remote control set temperature (total of the entire indoor unit) as the control air conditioning load. It is proposed to control the operation frequency (rotational speed) and the like of each compressor in a plurality of patterns by the air conditioning load. As a result, each compressor is operated at an operating frequency or the like suitable for the actual air conditioning load, thereby ensuring optimum air conditioning capacity and avoiding unnecessary stops.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2007-10200 [Patent Document 2] Japanese Patent Application Laid-Open No. 5-346259 [Patent Document 3] Japanese Patent Application Laid-Open No. 5-157374

By the way, in the air conditioners of Patent Documents 1 to 3, since the operating capacity (horsepower) of the indoor unit is not included in the calculation of the control air conditioning load, for example, a space (room) and a large capacity indoor unit in which only a small capacity indoor unit is installed. In the case where the spaces provided are mixed, the air-conditioning load calculated in the above-described form is considered to be the same even though the air-conditioning load is in a different state. For this reason, there exists a possibility that it may interfere with comfort especially in the space where a large capacity indoor unit is installed.

An object of the present invention is to provide an air conditioner that can improve comfort in a space where each indoor unit is installed while improving energy saving.

In order to solve the above problems, the invention described in claim 1 has a compressor for compressing a refrigerant with rotation and an outdoor unit heat exchanger that functions as a condenser of the refrigerant during the cooling operation and functions as an evaporator of the refrigerant during the heating operation. An air conditioner including an outdoor unit and a plurality of indoor units having an indoor unit heat exchanger that functions as an evaporator of a refrigerant during a cooling operation and a condenser of a refrigerant during a heating operation, comprising: A capacity acquiring means for acquiring a capacity respectively, a temperature difference acquiring means for acquiring a temperature difference between an actual air temperature and a target air temperature in all indoor units in operation among the plurality of indoor units, the capacity acquired for each indoor unit, and The value obtained by adding up the value obtained by multiplying the temperature difference in all the indoor units, Calculating means for calculating the air-conditioning load temperature difference by dividing the obtained capacity by the sum of all the indoor units, and a rotational speed control means for controlling the upper limit of the rotational speed of the compressor based on the calculated air-conditioning load temperature difference. It is a summary to provide.

According to the said structure, the capacity | capacitance (horsepower) of each indoor unit in operation is included in calculation of the said air conditioning load temperature difference as a control air conditioning load. The upper limit of the rotational speed of the compressor is controlled based on the calculated air conditioning load temperature difference. Thus, for example, even in a case where a space (room) where only a small capacity indoor unit is installed and a space where a large capacity indoor unit are installed are mixed, an optimum air conditioning capability corresponding to an air conditioning load can be ensured in each indoor unit. The comfort in the space where each indoor unit is installed can be improved. In addition, unnecessary shutdown of the compressor can be avoided, thereby improving energy saving.

In the air conditioner according to claim 2, the air conditioner according to claim 1 is characterized in that the rotational speed control means is based on the air-conditioning load upper limit rotational speed which is updated at regular intervals after the establishment of a predetermined condition indicating a stable state of the system. A control effect amount calculating means for controlling an upper limit of the rotational speed of the compressor and calculating a control effective amount by subtracting the previous air conditioning load temperature difference from the previous air conditioning load temperature difference calculated by the calculating means, and the previous air conditioning load upper limit The control amount calculating means for calculating the last control amount by subtracting the previous air conditioning load upper limit rotation speed from the rotation speed, and the value of the previous air conditioning load upper limit rotation speed divided by the previous control amount divided by the control effective amount and multiplied by the present air conditioning load temperature difference. With air-conditioning load upper limit rotational speed calculating means for calculating the next air-conditioning load upper limit rotational speed in addition to To the point.

According to the above configuration, the air-conditioning load upper limit rotational speed, which is the upper limit of the rotational speed of the compressor, is a value obtained by multiplying the current air-conditioning load temperature difference by a value obtained by dividing the previous control amount by the control effect amount and the previous air-conditioning upper limit rotational speed. It is calculated. That is, the next control amount (the next air conditioning load upper limit rotation speed minus the previous air conditioning load upper limit rotation speed) is determined based on the last control amount and the air conditioning load variation (control effect amount) when the control amount is given. . In this way, when calculating the air conditioning load upper limit rotation speed, the previous control amount and the air conditioning load variation amount (control effect amount) when the control amount is applied are reflected, thereby limiting the upper limit of the rotational speed of the compressor originally required from the air conditioning load. It is possible to calculate more accurately, and it is possible to quickly reach the air temperature of the space where each indoor unit is installed by the target air temperature while improving energy saving by suppressing the start-stop frequency of the compressor. have.

In the air conditioner according to claim 1 or 2, in the air conditioner according to claim 1 or 2, when the calculated air-conditioning load temperature difference exceeds a predetermined air-conditioning load temperature difference, the rotational speed of the compressor by the rotational speed control means The gist of the present invention is to provide a stop means for stopping the upper limit control of the control.

According to the above configuration, for example, the air conditioning load on the control is increased due to an increase in the operating capacity accompanied by 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 exceeds a predetermined air regulating load temperature difference, the upper limit control of the rotational speed of the compressor based on the air conditioning load temperature difference is stopped by the stop means. Therefore, it is possible to prevent the compressor's rotational speed, that is, the air conditioning capacity, from being unnecessarily reduced in the state of high air conditioning load, and maintain comfort in the space where each indoor unit is installed.

In the air conditioner according to claim 3, the air conditioner according to claim 3 includes: a low pressure side pressure sensor and a high pressure side pressure sensor for detecting a pressure in a suction pipe and a pressure in a discharge pipe of the compressor, respectively; In the cooling operation, when the pressure of the suction pipe exceeds the predetermined pressure on the low pressure side, and when the pressure of the discharge pipe falls below the predetermined pressure on the high pressure side in the heating operation, It is a main idea to stop the upper limit control of the rotational speed of the compressor.

According to the above configuration, for example, in the case of a cooling operation, when the pressure of the suction pipe exceeds the predetermined pressure on the low pressure side due to an increase in operating capacity accompanied with an increase in the outside air temperature, an increase in the number of indoor units during operation, or the like, that is, When the evaporation temperature of the refrigerant correlated with this pressure is high and the air conditioning load (cooling load) is high, the upper limit control of the rotational speed of the compressor is stopped by the stop means. Similarly, at the time of heating operation, when the pressure of the discharge pipe falls below a predetermined pressure on the high pressure side, i.e., correlates with this pressure due to a decrease in the outside air temperature, an increase in the operating capacity accompanied with an increase in the number of indoor units during operation, or the like. When the condensation temperature of the refrigerant is low and the air conditioning load (heating load) is high, the upper limit control of the rotational speed of the compressor is stopped by the stop means. Therefore, it is possible to prevent the compressor's rotational speed, that is, the air conditioning capacity, from being unnecessarily reduced in the state of high air conditioning load, and maintain comfort in the space where each indoor unit is installed.

According to 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.

1 is a refrigerant circuit diagram showing an embodiment of the present invention.
2 is a graph showing the relationship between temperature and pressure at the time of condensation or evaporation.
3 is a flowchart showing a control mode of the present embodiment.

<Mode for carrying out the invention>

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment which actualized this invention is described according to drawing.

1 is a circuit diagram showing a heat pump type air conditioner 1 according to the present embodiment. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 10 and a plurality of indoor units 30. In addition, each of the indoor units 30 has a capacity selected and set according to the size of the space (room) to be installed, and the capacity of the at least one indoor unit 30 is equal to the capacity of the other indoor units 30. It may be different.

The outdoor unit 10 is provided with a compressor 12 that compresses the refrigerant with rotation. The compressor 12 compresses the refrigerant sucked from the suction pipe 12a and delivers the refrigerant to the 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 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. Connected.

The outdoor unit heat exchanger 15 functions as a condenser of the refrigerant during the cooling operation, and functions as an evaporator of the refrigerant during the heating operation, and the indoor unit 30 (the electromagnetic expansion valve 32) through the refrigerant pipe 13h. Is connected to. In addition, a check valve 21 for allowing the flow of the coolant to the indoor unit 30 is disposed in the refrigerant pipe 13h, and the electromagnetic expansion valve 22 is provided in parallel with the check valve 21. It is arranged.

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

Next, an operation related to air conditioning of the air conditioner 1 will be described. In addition, the flow of a refrigerant | coolant at the time of each operation of cooling and heating is shown by the solid line arrow and the broken line arrow.

First, in the cooling operation, the refrigerant exiting the discharge pipe 12b of the compressor 12 passes through the four-way valve 14 and is then led to the outdoor unit heat exchanger 15 functioning as a condenser. In the outdoor unit heat exchanger (15), the refrigerant loses heat by outdoor air (outside air) to condense and liquefy. Thereafter, the refrigerant guided to the indoor unit 30 through the check valve 21 is depressurized by the electromagnetic expansion valve 32 and vaporizes the heat of the indoor air by the indoor unit heat exchanger 31 which functions as an evaporator. . Thereafter, the refrigerant returns to the suction pipe 12a of the compressor 12 through the four-way valve 14 and the accumulator 18. By passing through the above process, the room is cooled.

On the other hand, in the heating operation, the refrigerant exiting the discharge pipe 12b of the compressor 12 passes through the four-way valve 14 and is led to the indoor unit 30. The refrigerant is condensed and liquefied by releasing heat into the air in the room from the indoor unit heat exchanger 31 which functions as a condenser. Thereafter, the refrigerant decompressed in the electromagnetic expansion valve 32 is further decompressed in the electromagnetic expansion valve 22 to be led to the outdoor unit heat exchanger 15. The refrigerant absorbs and vaporizes heat of outdoor air in the outdoor unit heat exchanger 15 which functions as an evaporator. Thereafter, the refrigerant through the four-way valve 14 from the outdoor unit heat exchanger 15 returns to the suction pipe 12a of the compressor 12 through the accumulator 18. By going through the above process, the room is heated.

Here, the outdoor unit 10 is provided with a control device 41 for driving control of the compressor 12 or the like. This control device 41 is mainly composed of a microcomputer, the low pressure side pressure sensor 42 which detects the refrigerant pressure PL of the suction pipe 12a, and the refrigerant pressure PH of the discharge pipe 12b. It is electrically connected to the high pressure side pressure sensor 43 which detects this.

On the other hand, each indoor unit 30 is provided with a control device 46 for driving control of the electromagnetic expansion valve 32 or the like. This control device 46 mainly comprises a microcomputer, and is electrically connected to a temperature sensor 47 that detects the suction temperature Ts as the air temperature of the indoor unit 30. Moreover, the control apparatus 46 is set temperature (setting temperature of an operation panel, a remote control, etc.) Tm as a target air temperature set to the said indoor unit 30, and capacity | capacitance (horsepower) of the said indoor unit 30. (PW) is stored in the built-in storage means.

The control device 41 is configured to acquire the suction temperature Ts, the set temperature Tm, the capacity PW, and the like of each indoor unit 30 during operation through an appropriate communication means (capacity acquisition means). Based on the temperature difference acquisition means, the suction temperature Ts, the set temperature Tm and the capacity PW, to calculate the air-conditioning load of the whole apparatus (air-conditioning load totaled by all the indoor units 30) (operation 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 upper limit rotation speed control") is for lowering the rotation speed of the compressor 12 for the purpose of improving energy saving.

Alternatively, the controller 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, referred to as “evaporation pressure request control during cooling”). 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 of the discharge pipe 12b (hereinafter referred to as "condensation pressure demand control during heating"). Also called). In addition, when the cooling evaporation pressure demand control or cooling condensation pressure demand control (hereinafter also referred to as "request rotation speed control") is executed, the maximum operating speed Nmax is set as the upper limit rotation speed of the compressor 12. do. This use area maximum rotation speed Nmax is the upper limit rotation speed of the specification (system) which can avoid abnormal overheating of the control apparatus 41, the overload operation of the compressor 12, etc., for example. Therefore, at the time of performing the required rotational speed control, the rotational speed of the compressor 12, that is, the air-conditioning capacity is sufficiently secured, and the comfort in the space where each indoor unit 30 is installed is quickly improved.

Here, the rotation speed control mode of the compressor 12 during the cooling operation by the control device 41 will be described in more detail. 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 unit 41 controls the above-described required rotational speed control of the compressor 12 (evaporation pressure demand during cooling). Control). And when the predetermined time (for example, 5 minutes) or more passes after starting the outdoor unit 10, the control apparatus 41 starts calculation of the air conditioning load temperature difference (DELTA) Ts according to following formula (1). That is, the control device 41 continues to control the required rotational speed until the predetermined time elapses after starting the outdoor unit 10, and does not calculate the air conditioning load temperature difference [Delta] Ts. This is because the system is stabilized at the minimum before the upper limit control of the rotational speed of the compressor 12 described above.

Air-conditioning load temperature difference (ΔTs) = ((capacity (PW) × (suction temperature (Ts)-set temperature (Tm)) of each indoor unit 30 in operation) summed in all indoor units 30 in operation) (Total value of total capacity PW of each indoor unit 30 in operation in all indoor units 30 in operation). (One)

The air load load temperature difference ΔTs calculated as described above includes the capacity PW of each indoor unit 30 during operation. In the controller 41, the air-conditioning load temperature difference ΔTs is lower than the predetermined temperature difference DTc (for example, 2 ° C), and the evaporation temperature VT of the refrigerant is a predetermined temperature VTc (for example, For example, the air conditioner load upper limit rotational speed control mentioned above is started by below 6 degreeC). 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 pressure side pressure sensor 42.

That is, even if the predetermined time elapses more than the predetermined time after starting the outdoor unit 10, the control device 41 rotates the compressor 12 in the operating region where the air conditioning load temperature difference ΔTs is large and the air conditioning load as the whole apparatus is large. Since the speed need not be lowered, the air conditioning upper limit rotation speed control is not started (waiting). Alternatively, even after the predetermined time has elapsed since the start of the outdoor unit 10, the control device 41 has a high evaporation temperature (VT) of the refrigerant, which can be considered to be a high extraction temperature of the indoor unit 30 as the whole device. In the operating region in which the compressor 12 is lowered, the evaporation temperature VT is further increased, and the suction temperature of the indoor unit 30 may be increased to impair comfort. Do not initiate (wait).

When the system is stable and it is determined that the air conditioning load as the whole apparatus is lowered and there is no possibility of impairing the comfort, the controller 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 rotation speed of the compressor 12 by "0.9" as the initial rotation speed (initial value) of the control. Then, the control device 41 performs the upper limit control of the rotational speed of the compressor 12 at the initial rotational speed, and then waits until a predetermined time T (for example, 30 seconds), which is the rotational speed control period, has passed. do. In the next control cycle after the predetermined time T has elapsed, the control device 41 is based on the control amount ΔN and the control effect amount E according to the following equation (2). Calculate (air load upper limit rotation speed calculation means, control effect amount calculation means, control amount calculation means).

HVAC upper limit rotation speed (N (i)) = previous HVAC upper limit rotation speed (N (i-1)) + (last control amount (ΔN (i-1)) / control effect amount (E (i)) ) × Air-conditioning load temperature difference (ΔTs (i))

(i is the number of control cycles)

only,

Last control amount (ΔN (i-1)) = Last air load upper limit rotation speed (N (i-1))-Last air conditioning load upper limit rotation 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)

When starting the air conditioning load upper limit rotational speed control, when the rotational speed of the compressor 12 is multiplied by "0.9" as the initial rotational speed, the compressor 12 is used as the initial value of the last control amount. The value obtained by multiplying the speed by "O.1" is adopted.

That is, the next control amount ΔN (i) (= air-conditioning load upper limit rotation speed N (i))-the previous air-conditioning load upper limit rotation speed N (i-1) for lowering the rotation speed of the compressor 12. ) Is determined based on the amount of change in air conditioning load (control effect amount E (i)) when the previous control amount ΔN (i-1) and the control amount ΔN (i-1) are applied. Thus, when calculating the air conditioning load upper limit rotation speed, the rotational speed of the compressor 12 originally required from the air conditioning load is reflected by reflecting the last control amount and the air conditioning load variation amount (control effect amount) when the control amount is given. The upper limit of is calculated more accurately.

Thereafter, the control device 41 repeats the same control (air load upper limit rotation speed control) for each elapse of the predetermined time T.

When the air conditioning load is increased due to the increase in the operating capacity accompanied by the increase in the outside temperature, the increase in the number of indoor units during operation, or the like when the air conditioning load upper limit rotation speed control is repeated in the above-described form, the control device 41 Since it is necessary to raise the rotational speed of the compressor 12 again, the air conditioning load upper limit rotational speed control is stopped (stopping means), and the above-mentioned required rotational speed control (evaporation pressure demand control at cooling) is resumed.

Specifically, the control device 41 has the air conditioning load temperature difference ΔTs equal to or greater than the 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. When the evaporation temperature VT of the refrigerant correlating with the predetermined pressure on the low pressure side exceeds the predetermined temperature VTc1 (for example, 10 ° C), the air conditioning load upper limit rotation speed control is stopped, and the required rotation speed Resume control. As a result, the rotational speed of the compressor 12 can be prevented from being lowered unnecessarily in the operating region where the air conditioning load temperature difference ΔTs is large and the air conditioning load as the whole apparatus is large. Alternatively, in an operation region in which the refrigerant evaporation temperature (VT) is high and the extraction temperature of the indoor unit 30 as a whole device is high, the rotational speed of the compressor 12 can be prevented from being lowered unnecessarily, and the indoor unit 30 It is possible to reduce the possibility of impairing comfort by increasing the extraction temperature. Further, in order to avoid the 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 increase the upper limit of the rotational speed.

Next, the rotational speed control mode of the compressor 12 during the heating operation by the control device 41 will be described. In addition, since the said control at the time of heating operation is basically performed according to the above-mentioned cooling operation, only the difference with the case of cooling operation is extracted and demonstrated here.

When the outdoor unit 10 is started, the control device 41 performs the above-described required rotation speed control (control of condensation pressure demand at the time of heating) of the compressor 12. When the predetermined time (for example, 5 minutes) has elapsed since the start of the outdoor unit 10, the control device 41 starts the calculation of the air conditioning load temperature difference ΔTs according to the following equation (3).

Air-conditioning load temperature difference (ΔTs) = ((capacity (PW) x (set temperature (Tm)-intake temperature (Ts)) of each indoor unit 30 in operation) summed in all indoor units 30 in operation) (Total value of total capacity PW of each indoor unit 30 in operation in all indoor units 30 in operation). (3)

In the controller 41, the air-conditioning load temperature difference ΔTs is lower than the predetermined temperature difference DTh (for example, 2 ° C), and the condensation temperature CT of the refrigerant is a predetermined temperature CTh (for example, 40 degreeC) or more, and the above-mentioned air conditioning load upper limit rotation speed control is started. As shown in FIG. 2, the condensation temperature CT is correlated with the pressure (condensing pressure) of the discharge pipe 12b and is detected by the high pressure side pressure sensor 43.

If it is determined that the system is stable and the air conditioning load as the whole apparatus is lowered and there is no possibility of impairing the comfort, the control unit 41 starts the air conditioning load upper limit rotation 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 equation (3) to equation (2) (air load upper limit rotation speed). Calculation means, control effect amount calculation means, control amount calculation means). The upper limit of the rotational speed of the compressor 12 originally required from the air conditioning load is reflected by reflecting the previous control amount and the amount of change in the air conditioning load (control effect amount) when calculating the air conditioning load upper limit rotation speed. More accurate calculations have already been made.

When the air conditioner load increases due to the decrease in the outside air temperature, the increase in the number of indoor units during operation, or the like when the air conditioner load upper limit rotation speed control is repeated for each elapse of the predetermined time T, the control device. Since 41 needs to raise the rotational speed of the compressor 12 again, the air-conditioning load upper limit rotational speed control is stopped (stopping means), and the above-mentioned required rotational speed control (condensation pressure demand control at the time of heating) is resumed. do. Specifically, in the controller 41, the air-conditioning load temperature difference ΔTs is equal to or higher than the predetermined temperature difference DTh1 (for example, 3 ° C), or the refrigerant pressure PH of the discharge pipe 12b is higher than the predetermined pressure on the high pressure side. If the condensation temperature CT of the refrigerant correlated to this is lower than the predetermined temperature CTh1 (for example, 35 ° C), the air conditioning load upper limit rotation speed control is stopped and the required rotation speed control is resumed. As a result, the rotational speed of the compressor 12 can be prevented from being lowered unnecessarily in the operating region where the air conditioning load temperature difference ΔTs is large and the air conditioning load as the whole apparatus is large. Alternatively, in the operating region where the refrigerant condensation temperature CT is low and the suction temperature of the indoor unit 30 as the whole apparatus is low, the rotational speed of the compressor 12 can be prevented from being lowered unnecessarily, and the indoor unit 30 is prevented. It is possible to reduce the possibility of impairing the comfort by lowering the extraction temperature of.

Next, the rotational speed control mode of the compressor 12 during the cooling operation by the control device 41 will be collectively described based on the flowchart of FIG. 3. When the processing shifts to this routine by turning on the operation panel of the indoor unit 30 or the remote controller, the outdoor unit 10 is started (S1). Then, the above-mentioned required rotation speed control (control of evaporation pressure at the time of cooling) of the compressor 12 is performed (S2). Subsequently, after the outdoor unit 10 starts up, it waits for the predetermined time or more to pass (S3), and the calculation of the air conditioning load temperature difference ΔTs is started in accordance with the above formula (1), and the air conditioning load temperature difference ΔTs is It is determined whether it is less than the predetermined temperature difference DTc (S4). Then, it is determined that the air conditioning load temperature difference ΔTs is lower than the predetermined temperature difference DTc, and it is determined whether the evaporation temperature VT of the refrigerant is lower than the predetermined temperature VTc (S5).

Subsequently, it is determined that the evaporation temperature VT of the refrigerant is lower than the predetermined temperature VTc, and the above calculation of the air conditioning load upper limit rotation speed is started (S6). That is, a value obtained by multiplying the current rotation speed of the compressor 12 by "O.9" as the initial rotation speed of the control is set (S7). After the air conditioning load upper limit rotation speed control is performed at this initial rotation speed, the air conditioner load upper limit rotation speed N is calculated according to the above formula (2) after waiting for the passage of the predetermined time T or more (S8) ( S9).

Next, it is determined whether the air conditioning load temperature difference ΔTs is equal to or greater than the predetermined temperature difference DTc1 (S10). Here, when it is determined that the air conditioning load temperature difference ΔTs is less than the predetermined temperature difference DTc1, it is again determined whether the evaporation temperature VT of the refrigerant is equal to or greater than the predetermined temperature VTc1 (S11). Here, if it is determined that the evaporation temperature VT of the refrigerant is lower than the predetermined temperature VTc1, the control returns to S8 and the same control (air load upper limit rotational speed control) is repeated. That is, after the air-conditioning load upper limit rotational speed control is performed at the air conditioning load upper limit rotational speed N updated and set in S9, the air-conditioning load upper limit rotational speed N is calculated the next time after waiting for the passage of the predetermined time T or more. .

In addition, when it is determined that the air conditioning load temperature difference ΔTs is equal to or greater than the predetermined temperature difference DTc1 or the evaporation temperature VT of the refrigerant is equal to or greater than the predetermined temperature VTc1, the calculation of the air conditioning load upper limit rotation speed is performed. It stops (S12). Then, the above-described required rotation speed control (evaporation pressure demand control at cooling) is performed, which makes the upper limit rotation speed of the compressor 12 the maximum rotation speed in the use area.

As described above, according to the present embodiment, the following effects can be obtained.

(1) In this embodiment, the capacity | capacitance PW of each indoor unit 30 in operation | movement is included in calculation of the air-conditioning load temperature difference (DELTA) Ts as control air conditioning load. The upper limit of the rotational speed of the compressor 12 is controlled based on the air conditioning load temperature difference ΔTs. Thus, 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 (in a case where an indoor unit having a different capacity is connected in a building multi-system or the like) are connected, each indoor unit 30 Optimum air-conditioning capacity corresponding to the air-conditioning load can be ensured, and the comfort in the space where each indoor unit 30 is installed can be improved.

That is, for example, there is a space where only a large indoor unit is installed (space A) and a space where only a small capacity indoor unit is installed (space B), and the difference between the set temperature of the space A and the room temperature does not change from 2 ° C. Consider the case where the difference between the set temperature of room B and the room temperature is changed from 2 ℃ to 0 ℃. When the control air conditioning load is simply calculated as "the difference between the set temperature and the room temperature" or "the sum of the difference between the set temperature and the room temperature", it is considered that the control air conditioning load is decreasing and the rotational speed of the compressor 12 is reduced. Goes down. On the other hand, in the present embodiment, since the room temperature of the A space does not change while being kept away from the set temperature, the air conditioning load temperature difference ΔTs as the control air conditioning load remains large. Therefore, excessive reduction of the rotational speed of the compressor 12 can be suppressed, and the rotational speed of the compressor 12 can be controlled by the driving capability originally requested. In addition, unnecessary stop of the compressor 12 can be avoided, and energy saving can be improved.

(2) In this embodiment, the air-conditioning load upper limit rotational speed N (i), which is the upper limit of the rotational speed of the compressor 12, is the last control amount ΔN to the previous air conditioning load upper limit rotational speed N (i-1). It is calculated by adding (i-1)) divided by the control effect amount E (i) to the product of the present air conditioning load temperature difference ΔTs (i). That is, the next control amount ΔN (the next air conditioning load upper limit rotation speed N (i) minus the previous air load upper limit rotation speed N (i-1)) is the previous control amount ΔN (i -1)) and the amount of change in air conditioning load (control effect amount E (i)) when the control amount ΔN (i-1) is applied. i)) reflects the amount of change in air conditioning load (control effect amount E (i)) when the previous control amount ΔN (i-1) and the control amount ΔN (i-1) are applied. Thus, the upper limit of the rotational speed of the compressor 12, which is originally required from the air conditioning load, can be calculated more accurately, and the indoor unit 30 can be improved while suppressing the start / stop frequency of the compressor 12 to improve energy saving. The suction temperature Ts of the space in which the is installed can be reached more quickly at the set temperature Tm.

That is, for example, if the difference between the suction temperature Ts and the set temperature Tm decreases the rotational speed of the compressor 12 in the state of 2 ° C, if the same rotational speed is given at the next control, the air conditioning load Even if it decreases, since the rotational speed of the compressor 12 is not fluctuated between some temperature ranges, the followability up to the set temperature Tm may deteriorate and the start / stop frequency may not be suppressed. On the other hand, in this embodiment, while considering how the control variation width (control amount) applied from the air conditioning load influences the air conditioning load variation amount (control effect amount), the difference between the suction temperature Ts and the set temperature Tm ( By calculating the next control variation based on the air conditioning load temperature difference ΔTs), the followability up to the set temperature Tm can be improved and the start / stop frequency can be suppressed.

(3) In the present embodiment, for example, the control capacity is increased due to an increase in operating capacity accompanied by 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 the air conditioning load temperature difference ΔTs, which is the air conditioning load, exceeds the predetermined temperature differences DTc1 and 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 capacity, from being unnecessarily lowered in the state of high air conditioning load, and to maintain comfort in the space in which the indoor units 30 are installed.

(4) In the present embodiment, for example, during the cooling operation, the refrigerant pressure PL of the suction pipe 12a is low in pressure due to an increase in operating capacity accompanied with an increase in the outside air temperature, an increase in the number of indoor units during operation, or the like. The air-conditioning load temperature difference ΔTs when the evaporation temperature VT of the refrigerant correlating to the refrigerant pressure PL is higher than the predetermined temperature VTc1 when the air-conditioning load (cooling load) is higher than the predetermined pressure on the side. Based on this, the upper limit control of the rotational speed of the compressor 12 is stopped. Similarly, in the heating operation, when the refrigerant pressure PH of the discharge pipe 12b is lower than the predetermined pressure on the high pressure side due to a decrease in the outside air temperature, an increase in the operating capacity accompanied with an increase in the number of indoor units during operation, or the like. That is, when the condensation temperature CT of the refrigerant correlated with the refrigerant pressure PH exceeds the predetermined temperature CTh1 and the air conditioning load (heating load) is high, the compressor 12 is based on the air conditioning load temperature difference ΔTs. The upper limit control of the rotation speed is stopped. Therefore, in a state where the air conditioning load is high, it is possible to prevent the rotational speed of the compressor 12, that is, the air conditioning capacity, from being unnecessarily lowered, and to maintain comfort in the space in which the indoor units 30 are installed.

(5) In this 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 cooling pressure PL (evaporation pressure) of the suction pipe 12a is stopped during the cooling operation. On the basis of the required rotational speed based on the rotational speed of the compressor 12 is controlled at the time of heating operation based on the required rotational speed based on the refrigerant pressure PH (condensation pressure) of the discharge pipe 12b. The air-conditioning capacity can be preferably secured even under a high load.

In addition, you may change the said embodiment as follows.

The present invention relates to an electric heat pump (EHP) type air conditioner in which the compressor 12 is driven by an electric motor, or a gas heat pump (GHP) type in which the compressor 12 is driven by a gas engine. You may apply to the kerosene heat pump (KHP) type | mold air conditioner by which the compressor 12 rotates by a roughening apparatus and a kerosene engine. In each of these cases, the rotational speed of the compressor 12 may be indirectly controlled through the rotational speed of the electric motor, the gas engine, or the kerosene engine.

In particular, in the case of employing an engine-driven air conditioner, the arrangement may be used in connection with the coolant circuit of the engine during heating operation, for example.

Next, the technical idea grasped | ascertained from the said embodiment and another example is described further below.

The air conditioner according to claim 4 is a request based on the pressure of the suction pipe at the time of cooling operation as the upper limit when the upper limit control of the rotational speed of the compressor is stopped by the stop means. The air conditioner is characterized by controlling the rotational speed of the compressor on the basis of the rotational speed, and based on the required rotational speed based on the pressure of the discharge pipe during the heating operation. According to the above arrangement, when the upper limit control of the rotational speed of the compressor is stopped, the pressure of the discharge pipe (at the time of heating operation) is based on the required rotational speed based on the pressure (evaporation pressure) of the suction pipe at the time of cooling operation. By controlling the rotational speed of the compressor on the basis of the required rotational speed based on the condensation pressure), it is possible to ensure the air-conditioning capacity even in a state where the air-conditioning load is high.

One … Air conditioner, 10... 12, outdoor unit; Compressor, 12a... Suction tube, 12b... Discharge tube, 15... Outdoor unit heat exchanger, 30. Indoor unit, 31. Indoor unit heat exchanger, 41. Control device (capacity acquisition means, temperature difference acquisition means, calculation means, rotation speed control means, control effect amount calculation means, control amount calculation means, air load upper limit rotation speed calculation means, stop means), 42. Low pressure side pressure sensor; High pressure sensor

Claims (9)

An outdoor unit having a compressor for compressing the refrigerant with rotation and an outdoor unit heat exchanger functioning as a condenser of the refrigerant during the cooling operation and an evaporator of the refrigerant during the heating operation;
In an air conditioner comprising a plurality of indoor units having an indoor unit heat exchanger that functions as an evaporator of a refrigerant during a cooling operation and functions as a condenser of a refrigerant during a heating operation,
Capacity measuring means for respectively acquiring capacity (horsepower) of all indoor units operating in the plurality of indoor units;
Temperature difference acquiring means for acquiring a temperature difference between an actual air temperature and a target air temperature of all the indoor units operating in the plurality of indoor units;
The air-conditioning load is obtained by dividing the value obtained by multiplying the capacity of the indoor unit obtained by the respective indoor units with the temperature difference in all the indoor units, and dividing the capacity of the indoor unit obtained by the indoor units by the total value in all the indoor units. Computing means for calculating a temperature difference;
And 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 method according to claim 1,
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 updated every predetermined period after the establishment of a predetermined condition indicating a stable state of the system, and calculated by the calculating means A control effect amount calculating means for calculating a control effective amount by subtracting the previous air conditioning load temperature difference from the previous air conditioning load temperature difference;
Control amount calculation means for calculating the last control amount by subtracting the previous air conditioning load upper limit rotation speed from the previous air conditioning load upper limit rotation speed;
The air-conditioning load upper limit rotation speed calculating means for calculating the next air-conditioning load upper limit rotation speed by adding the value of the previous air conditioning upper limit rotation speed divided by the previous control amount divided by the control effective amount and multiplied by the present air conditioning load temperature difference. Air conditioning device characterized in that. The method according to claim 1,
And the compressor has a low pressure side pressure sensor and a high pressure side pressure sensor for detecting the pressure of the suction pipe and the discharge pipe of the compressor, respectively. The method according to any one of claims 1 to 3,
And a stopping means for stopping the upper limit control of the rotational speed of the compressor, when the air conditioning load temperature difference obtained from the calculating means exceeds a predetermined air conditioning load temperature difference. The method according to claim 4,
The stop means rotates when the pressure of the suction pipe exceeds the predetermined pressure on the low pressure side during the cooling operation, and when the pressure of the discharge tube falls below the predetermined pressure on the high pressure side during the heating operation. And an upper limit control of the rotational speed of the compressor by a speed control means. The method according to claim 5,
The rotational speed of the compressor is the upper limit of the maximum rotational speed of the use area when the upper limit control of the rotational speed of the compressor is stopped by the stop means, and at the required rotational speed based on the pressure of the suction pipe during the cooling operation. In operation, the air conditioner is controlled at the required rotational speed based on the pressure of the discharge pipe. The method according to claim 1,
The rotational speed control means controls the rotational speed of the compressor at the required rotational speed based on the refrigerant pressure of the suction pipe during the cooling operation and the discharge pipe during the heating operation until the predetermined time or more passes after starting the outdoor unit. Rotational speed control method characterized in that. The method according to claim 1,
And said calculating means for controlling said rotational speed starts the operation after a predetermined time has elapsed after starting the outdoor unit. The method according to claim 1,
And the air conditioning load upper limit rotational speed control is started when the air conditioning load temperature difference is less than a predetermined temperature difference and the evaporation temperature of the refrigerant is below a predetermined temperature.

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