182 results about "Constant air volume" patented technology

The invention provides a system and a method for controlling the constant air volume of an air duct type air conditioning indoor unit. The method comprises the following steps of: outputting a constant duty ratio D by a central processing unit to drive a direct current motor; detecting the rotating speed of the direct current motor by a rotating speed detection module, and transmitting the rotating speed to a rotating speed comparison module; comparing the rotating speed with a motor rotating speed value of a rotating speed unit by the rotating speed comparison module to obtain static pressure, and outputting the static pressure to a storage module; and contrasting a required constant air volume and static pressure with the data stored in the target rotating speed unit by the central processing unit to obtain a motor rotating speed value, and controlling the direct current motor to reach the rotating speed value. According to the system and the method for controlling the constant air volume of the air duct type air conditioning indoor unit, the automatic identification of the static pressure can be realized according to different air duct lengths so as to control the constant air volume, so that the output of the constant air volume can be realized under any static pressure conditions.

The invention discloses a detection method and device for filth blockage of a filter screen of an air conditioner and the air conditioner. The method includes the steps that the target rotating speed obtained when a draught fan stably works according to the preset constant air volume at present is obtained after the draught fan of the air conditioner is controlled to run according to the default initial rotating speed; the initial rotating speed of the draught fan of the air conditioner is obtained when the draught fan runs according to the preset constant air volume for the first time; and whether filth blockage happens to the filter screen arranged in an air feeding pipeline of the air conditioner or not is determined according to the current target rotating speed and the initial rotating speed of the draught fan. The detection method and device solve the technical problem that in the prior art, filth blockage happening to the filter screen arranged in the air feeding pipeline of the air conditioner can not be accurately detected.

The invention discloses a system and a method for controlling a range hood capable of outputting constant air volume. The system comprises a controller; the controller is connected with a user control panel, a speed sensor, a current sensor and a storage, wherein the user control panel is used for enabling a user to input the initial air volume Qu; the speed sensor is used for detecting the actual speed n of a motor; the current sensor is used for detecting the actual current i of the motor; the storage is used for storing data such as the speed N, the current I, the static pressure P and air volume Q; the air volume is directly proportional to the speed; the static pressure is directly proportional to the square of the speed; the current is directly proportional to the cube of the speed. Through the judging whether the air volume Q is within the difference value delta Q range or not, the actual speed N is adjusted to change the air volume Q to achieve the purpose that the range hood can output constant air volume.

The invention provides a method and a system for adjusting constant air volume of a range hood. The system comprises a detection unit for detecting the parameters of a motor in the range hood, an air volume monitoring unit for obtaining the real-time air volume of the exhaust outlet of the range hood according to the parameters of the motor, and a control unit for regulating the parameters of the motor through an inverter so as to keep the real-time air volume constant. The parameters of the motor are obtained and the current air volume value is calculated, and then the monitored real-time air volume is fed back to the control unit so that the control unit is capable of regulating the rotating speed or the current of the motor according to the real-time air volume, and therefore, the purpose of regulating the real-time air volume is achieved and the output air volume is kept constant, and moreover, the oil fume suction effect is guaranteed.

The invention provides an air conditioner filter screen dirty blockage situation detection and air volume control method, and belongs to the field of air conditioner indoor unit filter screen dirty plug detection and air volume control. According to the invention, the problem that an existing indoor unit filter screen dirty blockage situation detection is inaccurate, and constant air volume judgment is inaccurate are solved. the technical scheme is as follows, the running parameters of the motor of the air conditioner indoor unit at different running speeds of the fan in the factory debuggingprocess are obtained, and a running power standard value is calculated, and the standard parameter value is recorded as a standard parameter value; in the use process of the air conditioner, running parameters of the motor of the air conditioner indoor unit are acquired in real time, and corresponding real-time running power values are calculated; the running power standard value and the real-timerunning power value are compared; and if the real-time running power value is not equal to the running power standard value, the rotating speed of the fan is increased or decreased until the real-time running power value reaches the operating power standard value, and when the rotating speed of the fan reaches a set value, and the real-time running power value is smaller than the operating powerstandard value, the control unit sends out a command which needs to be cleaned by the filter screen.

A method for providing energy-efficient temperature and humidity control with uniform ventilation air distribution in a constant-volume zoned heating and cooling systems. The method utilizes an air-to-air heat exchanger that regulates the temperature of the supply air to a space, using the temperature differential between supply air and return (room) air and regulating the flow of return air through the heat exchanger.

The invention discloses a constant air volume conditioner and a control method thereof. According to the control method, basic reference data, related to air supply volume and obtained when an indoor fan operates at a standard operating speed Nb and an air guide reaches a maximum outlet position and a position deviating from the maximum outlet position, is preset in a storage module of the conditioner; an analytical processing module of the conditioner calls the basic reference data and acquires compensated speed of the indoor fan according to a deviation of the air guide deviating from the maximum outlet position; the analytical processing module adjusts the speed of the indoor fan according to the compensated speed. According to the constant air volume conditioner and the control method thereof, the compensated speed of the indoor fan is acquired through calling the basic reference data and according to the deviation of the air guide, the speed of the indoor fan is adjusted according to the compensated speed so as to change the air supply volume, and constant air supply volume is maintained; therefore, air supply volume stability is improved for the conditioner, and refrigerating and heating performances of the conditioner are improved.

The invention relates to a central air conditioning system, in particular to an air pipe type air conditioner. According to the technical scheme, a direct current fan motor is adopted, a static pressure recognition mode can run before an indoor unit is used, automatic operation is started through a unit, resistance characteristics of an air duct are recognized through changing the revolving speed, and the revolving speed suitable for resistance is found. After the recognition is achieved, the air conditioner automatically stops, and the revolving speed is recorded; the revolving speed is taken as a target revolving speed during following running, air blast capacity of the unit is guaranteed to be constant, and the full output capacity is ensured; after the static pressure reorganization method is adopted, the air blast capacities of the air pipe type air conditioner under different static pressures are recognized on the condition of normal voltage, and the deviation of the output air capacity of the indoor unit is within + / -5%; the deviation of the output air capacity of the indoor unit is also within + / -10% on the condition of abnormal voltage.

The invention discloses a constant-air volume control method and device for an indoor unit of an air conditioner and the indoor unit of the air conditioner. The constant-air volume control method includes that acquiring the real-time power of a motor of the indoor unit of the air conditioner under a certain rotating speed; in consideration of the influence of the current input voltage of the air conditioner on the motor power, correcting the real-time power of the motor to obtain a new power value; calculating the power difference between the corrected power value of the motor and a preset standard power value under the motor rotating speed corresponding to the corrected power value of the motor; calculating a target rotating speed of the motor needed for arriving at a preset constant air volume according to the power difference, and controlling the motor to run in the target rotating speed. The constant-air volume control method and device for the indoor unit of the air conditioner and the indoor unit of the air conditioner can precisely detect the air resistance and realize the constant air volume control for the indoor unit of the air conditioner, and meanwhile, the influence of the voltage factor of a power grid of the user is avoided, and the stable refrigerating or heating effect of the air conditioner is guaranteed.

The invention discloses a PM motor direct power control constant-air-volume control method and an HVAC system using same. The control method comprises the steps of step A, receiving the target air volume IN-CFM through a starting motor; step B, obtaining a corresponding function P=f (n) according to the target air volume IN-CFM; step C, entering a direct power control constant-air-volume control mode: controlling the motor to reach a stable work point (pt, nt) along the function P=f (n) control track; step D, calculating motor real-time input power Pi according to motor operation parameters, wherein delta P= / Pt-Pi / ; step E, maintaining the prior work point if delta P is smaller than the set value Pset; step F, calculating whether the speed ring operation time is reached if delta P is larger than or equal to the set value Pset, and maintaining the prior work point if the operation time is not reached; step G, entering the speed control circuit adjusting speed, that is, making pt=Pi and nt=ni, if the time is reached to achieve a novel work point (Pi, ni) on the track, and returning to the step C. The control method and the HVAC system have the advantages that the method is particularly applicable to air volume control in the steady state, the algorithm is concise, the requirement for CPU operation is not high, the cost is low, and the control accuracy is high.

The invention relates to the field of air filtration, in particular to an intelligent constant control method and device for the air filtration air volume. The intelligent constant control method and device can be used for intelligent constant control over the air filtration air volume. A large number of air purifiers and novel air filtration fans are used. But air filters of the air purifiers and air filters of the novel air filtration fans are gradually blocked by particulate matter along with using, so that the air volume is reduced, and accordingly experience brought to users are that the filtration efficiency of the air filters is poorer and poorer, and even a certain filtration effect can only be achieved a long time after starting. According to the intelligent constant control method and device, the air pressure difference between the front end and the rear end of each air filter is detected to control the work state of the fans, so that the air volume is made to be constant under the circumstance that filter screens are gradually blocked by dust, and the users are made to experience comfortably. The feeling that the air volume is smaller and smaller along with using is avoided, and the service life of the air filters is prolonged furthest. Meanwhile, when the air filters reach the design service life, replacement is pointed out. According to the intelligent constant control method and device, the filters are convenient to replace. The intelligent constant control method and device are suitable for the air purifiers and novel air filtration fans of any types, so that the application range is broadened.

The invention relates to a clean purification air-conditioning control method for an operating room. The clean purification air-conditioning control method comprises the following steps of: executing the function of air regulation by using an electric adjustable air valve A mounted in a fresh air passage, a frequency-variable fan mounted in a circulating air passage and an electric adjustable air valve B mounted in a discharge air passage, so as to carry out control on the air regulation of the operating room under different working conditions, wherein the control is achieved by comparing operating progress information inputted through a keyboard and the indoor pressure value of the operating room acquired by a pressure sensor mounted in the operating room with data stored in a data storage unit by a processing unit, and calling out preset fresh air volume values and circulating air volume values corresponding to different operating stages according to the compared result to adjust the opening degree of the electric adjustable air valve of the fresh air passage, so as to control air volume; and adjusting a circulating fan frequency converter to execute frequency conversion, so as to control the air volume.

The invention discloses a constant-air-volume control method for a range hood. According to the method, the number of all internally-arranged gears of an indoor unit is x, and the default initial gearof a high gear air volume interval [ Q1, Q2 ] is x / 2; when the operating gear of an indoor range hood is equal to x and the air volume is smaller than Q1, target air volume is reduced from [ Q1, Q2 ]to [ q1, q2 ], so that the gear is reduced, and noise is reduced; and when the target air volume is in the interval [ q1, q2 ], the number of the operating gear is smaller than x-2, the target air volume is changed from [ q1, q2 ] to [ Q1 and Q2 ], so that the air volume is increased, and the oil fume suction effect is improved. The method has the advantages that a constant-air-volume control method of the range hood is applied to a central flue system; from the point of reducing noise, when the start-up rate is extremely high, the air volume interval is properly reduced, a bit of the oil fume suction effect is sacrificed, so that the noise is reduced; the air exhaust amount of high floors is reduced, so that the flue exhaust power of low floors is increased, and the air exhaust volume ofthe low floors is increased; and meanwhile, the air volume of all the floors is ensured to be balanced and capable of meeting the flue exhaust requirement, so that the use experience of users is good.

The invention discloses an air conditioner and a draught fan air volume control method and device thereof. The draught fan air volume control method for the air conditioner comprises the steps that the environment temperature of the environment where the air conditioner is located is collected; the gear of a draught fan of the air conditioner is determined; the duty ratio of the draught fan of the air conditioner is determined according to the environment temperature and the gear of the draught fan; and the air volume of the draught fan of the air conditioner is adjusted according to the duty ratio. By means of the air conditioner and the draught fan air volume control method and device thereof, the problem that in the prior art, the air volume of a draught fan in the air conditioner draught fan adjusting process is not constant is solved, and accordingly the effect of outputting the optimal constant air volume in the air conditioner draught fan adjusting process is achieved.

The invention provides an automatic static pressure regulation control method and system for an air duct type indoor unit. The method includes the following steps that after being powered on, a direct-current motor of the indoor unit is controlled to run at the rotating speed corresponding to preset static pressure, a running current value is detected after the direct-current motor runs for a first period of time, whether the detected running current value is within a target current range corresponding to the preset static pressure is judged through comparison, and stable regulation control over static pressure is conducted according to judgment and comparison results. The rotating speed of the direct-current motor is automatically regulated by comparing the detected running current value with the target current range, so that the air duct type indoor unit keeps output of a constant air volume in the installing and using process all the time, and the requirement of users for use comfort is met.

A method for providing energy-efficient temperature and humidity control with uniform ventilation air distribution in a constant-volume zoned heating and cooling systems. The method utilizes an air-to-air heat exchanger that regulates the temperature of the supply air to a space, using the temperature differential between supply air and return (room) air and regulating the flow of return air through the heat exchanger.

A method for controlling constant air volume of an ECM motor in an HVAC system. The method includes: a) acquiring a target air volume Qset input from an external, determining a function Itad=f(n) corresponding to the target air volume Qset by the microprocessor, in which Itad represents a bus current, n represents a rotational speed of the motor; b) acquiring a calculated bus current Itad according to the rotational speed n and the function Itad=f(n), and detecting a real-time bus current Ibus; and c) comparing the calculated bus current Itad with the real-time bus current Ibus by the microprocessor for closed-loop control; when Itad>Ibus, increasing the rotational speed n of the motor; when Itad<Ibus, decreasing the rotational speed n of the motor; and when Itad=Ibus, stopping regulating the rotational speed n and returning to B) for continuing the control of the constant air volume.

The invention discloses a stepless constant-air volume control method and control device of a fan, and the fan. The stepless constant-air volume control method of the fan comprises the steps that a target constant air volume value of the fan is acquired; a target torque of the fan is determined according to the target constant air volume value, and the fan is controlled to operate under the targettorque; the actual rotating speed and the actual torque of the fan during operation are acquired; the air volume and air pressure of the fan are worked out according to the actual rotating speed andthe actual torque of the fan during operation, and a target rotating speed range of the fan is worked out according to the air volume and air pressure of the fan and a preset stepless constant-air volume mathematic model; a current compensation value required by the fan to reach the target rotating speed range is determined, and current compensation is conducted according to the current compensation value to control the fan to constantly output an air volume at the target constant air volume value. According to the stepless constant-air volume control method and control device of the fan, andthe fan, complex test procedures and a large quantity of calculation in the process of fitting an air volume and air pressure characteristic curve are reduced, and the capacity of the fan to output aconstant air volume under different air pressures is improved.

The invention discloses a direct current fan control method and system. The method comprises the steps of obtaining the target air volume; obtaining the lower-limit air volume and the upper-limit air volume of a range within which the target air volume is located so that a proportionality coefficient can be obtained; collecting the current rotating speed and a torque current of a driving motor; according to the current rotating speed and the torque current, obtaining a low air volume torque current and a high air volume torque current through the lower-limit air volume and the upper-limit air volume; and according to the proportionality coefficient, the low air volume torque current and the high air volume torque current, obtaining a target torque current so that a direct current fan can be controlled to operate according to the target torque current. By means of the control method, the target torque current can be determined according to the target air volume, the current rotating speed and the torque current, and thus the direct current fan is controlled according to the target torque current; the purpose of constant air volume output is achieved; control precision is improved; and the direct current fan control method is simple and easy to implement.

The invention discloses a constant-air-volume motor drive control method for a fan. The constant-air-volume motor drive control method comprises the following steps: determining Duty 0, N0, I0 and CFM0, keeping Duty0 unchanged, and blocking the sectional area of an air flue opening; respectively obtaining Nx, Ix and CFMx under different Sx values while an initial sectional area is S0 and an effective ventilation sectional area is Sx; obtaining a stepless speed regulation datum reference curve; enabling the CFMX to be identically equal to CFM0 by regulating Dutyx, thereby obtaining current Nx, Ix and Dutyx; obtaining a constant-air-volume regulating datum curve; setting Dutyx as Duty0, and measuring Nx and Ix; according to the stepless speed regulation datum reference curve and the constant-air-volume regulating datum curve, correcting a duty ratio to be Dutyx, and enabling air volume CFMx of an air outlet to be identically equal to CFM0. In case of no sensor feedback, the control method realizes intelligent control of constant air volume of the fan, and improves the reliability of motor control.

The invention discloses a constant air volume control method of an air conditioner. The air conditioner comprises an air pressure sensor; the constant air volume control method of the air conditionerincludes steps of detecting current air pressure of an air outlet of the air conditioner through the air pressure sensor, acquiring the target air volume set by a user; calculating the current air volume according to current air pressure, and calculating the air volume differential value between the current air volume and the standard air volume; correspondingly controlling the motor rotate speedof the air conditioner according to the differential value of the air volume, thereby keeping the constant air volume of the air conditioner. The invention further discloses an air conditioner and a computer readable storage medium. According to the constant air volume control method of the air conditioner, the air conditioner and the computer readable storage medium, the constant air volume control of an indoor air conditioner is realized, and the cooling and heating effects of the air conditioner are improved.

The invention discloses a motor fan device, air flowability adjusting equipment and an air capacity control method. The motor fan device comprises a motor, a processor, a storage device for storing alookup table and a speed detection unit. The processor obtains the target driving voltage and the corresponding target rotating speed of the motor by inquiring the lookup table or carrying out calculation based on data in the lookup table according to the preset air capacity. When the rotating speed difference between the practical rotating speed and the target rotating speed of the motor is not within a preset rotating speed difference range, a gain value is repeatedly increased to the target driving voltage to obtain the new target driving voltage, the target rotating speed corresponding tothe new target driving voltage and the practical rotating speed of the motor are obtained, whether the rotating speed difference between the practical rotating speed and the target rotating speed is within the preset rotating speed difference range or not is judged, the operations are carried out till the rotating speed difference is within the preset rotating speed difference range, and the corresponding target rotating speed at the movement is kept to drive the motor. An air flowability adjusting system can output the constant air capacity.

The invention relates to a shared oil smoke emission vertical pipe system and a control method thereof. The shared oil smoke emission vertical pipe system comprises a controller, oil smoke exhausters, frequency convertors, an oil smoke emission vertical pipe and a plurality of oil smoke emission horizontal pipe assemblies. Oil smoke emission horizontal pipes are connected with the oil smoke emission vertical pipe through electric air valves. Starting switches and actuators are all electrically connected with the controller. The electric air valves are connected with one ends of constant air volume valves. The other ends of the constant air volume valves are connected with the oil smoke emission horizontal pipes. The oil smoke exhausters are connected with the controller through the frequency convertors. The starting switches are used for sending starting signals to the controller. The controller is used for controlling the electric air valves to open after receiving the starting signals, and the running air volumes of the oil smoke exhausters are controlled through the frequency convertors. According to the shared oil smoke emission vertical pipe system, the oil smoke emission vertical pipe is shared by the oil smoke emission horizontal pipe assemblies, and through controlling of the controller and the frequency convertors over the oil smoke exhausters, the oil smoke emission requirements for the oil smoke emission vertical pipe shared by the oil smoke emission horizontal pipe assemblies are met, and full-automatic intelligent control is achieved.

An HVAC controller, a method of operating a constant air volume (CAV) HVAC unit and a CAV HVAC system are disclosed herein. In one embodiment, the HVAC controller includes: (1) an interface configured to receive both a latent cooling demand and a sensible cooling demand and (2) a processor configured to direct both a dehumidification function and a discharge air temperature control function for a CAV HVAC system employing the latent cooling demand and the sensible cooling demand.

The invention provides a low noise fast response permanent magnet direct current brushless motor for controlling constant air volume, which comprises a shell, a stator and a rotor in the shell, wherein the stator comprises a stator iron core and a stator winding which are fixed on the inner wall of the shell, the rotor comprises a main shaft and a rotor iron core, the external circumferential direction of the rotor iron core is evenly fixed with rotor magnetic poles which comprise radial magnetized magnetic steel and tangential magnetized magnetic steel, the radial magnetized magnetic steel is a main magnetic pole, and the tangential magnetized magnetic steel which is arranged between adjacent main magnetic poles is a side magnetic pole. Or, the inner circumferential direction of the rotor iron core is evenly embedded with built-in radial magnetized rectangular strip magnetic steel which is the main magnetic pole, and the tangential magnetized magnetic steel which is arranged between adjacent main magnetic poles is the side magnetic pole. The low noise fast response permanent magnet direct current brushless motor gathers magnetic through two ways of radial and tangential direction, thereby observably increasing the air gap flux density, greatly reducing the mechanical time constant, increasing fast response, controlling the constant air volume in a high performance, which leads a motor to steadily operate in high efficiency, saving energy, low fluctuation, low noise, frequent starting and rapid response, and the low noise fast response permanent magnet direct current brushless motor can achieve the miniaturization and lightening of the motor.

The invention provides a parallel type draught fan power type variable air volume tail end device and a control method thereof. The parallel type draught fan power type variable air volume tail end device comprises a draught fan, a primary air valve connected with the draught fan in parallel, and a direct digital controller. The draught fan comprises a motor, and the draught fan further comprises a check valve with a baffle. The baffle is fixed to the position of a draught fan air outlet of the draught fan through a rotating shaft. When the draught fan is static, the baffle is kept vertical so that primary air can be prevented from entering the draught fan through the check valve; and when the draught fan works, at least part of the baffle is opened. According to the parallel type draught fan power type variable air volume tail end device, when the draught fan is static, the primary air can be prevented from entering the draught fan through the check valve, and when the draught fan works, the baffle can be opened. Through the test, the resistance losses of the baffle can almost be ignored when the draught fan runs, abnormal noise is not generated at the position of the baffle, and constant-air-volume running of the parallel type draught fan power type variable air volume tail end device can be achieved.

The invention belongs to the technical field of air conditioners, and provides a draught fan control method and device and an air conditioner. The draught fan control method comprises the steps that firstly, initial rotating speed is obtained according to preset air quality to enable a draught fan to operate at the initial rotating speed; then, a preset electrical parameter is obtained according to the preset air quality and the initial rotating speed; an actual electrical parameter of the draught fan is detected in real time; and when a difference value of the preset electrical parameter andthe actual electrical parameter is not in a preset numerical value interval, the rotating speed of the draught fan is adjusted step by step, and difficult calculation of resistance, limited dial-up gear, human factor interference and environmental factor interference caused by air output volume of a dial-up adjusting draught fan are avoided and the accuracy and efficiency of constant air volume control of the draught fan are improved due to the fact that the purpose of detecting actual air volume through the actual electrical parameter of a detecting draught fan is achieved by using a relationship of the electrical parameter and the air volume of the draught fan, and the air output air volume of the draught fan is enabled to reach the preset air volume by adjusting the rotating speed of the draught fan.

The invention provides a constant air volume control method of an air conditioner, and belongs to the field of constant air volume control of the air conditioner indoor unit. The key point of the technical scheme is as follows, the running parameters of a motor of the air conditioner indoor unit at different running speeds of the fan in the factory debugging process are acquired, and the standardvalue of the running power is calculated; in the using process of the air conditioner, the running parameters of the motor of the air conditioner indoor unit are acquired in real time, and the corresponding real-time running power value is calculated; the running power standard value and the real-time running power value are compared; if the real-time running power value is smaller than the running power standard value, the rotating speed of the fan is increased; when the rotating speed of the fan is increased, the running power standard value can be reached if the real-time running power value is increased, the rotating speed is increased to the corresponding rotating speed, and if the rotating speed of the fan is increased to the maximum rotating speed, the real-time running power valuecan still not reach the operating power standard value, and then alarm information is sent out.

Disclosed therein is a dual zone type air conditioner for a vehicle, which includes: an air volume control door mounted between a blower and an evaporator for controlling the degree of opening of first and second passageways so as to control the volume of air blown to the inside of an air-conditioning case; and bypass passageways disposed in the air volume control door to supply a predetermined air volume to a closed passageway even though the air volume control door is at the location to close the first passageway or the second passageway, thereby preventing a sudden change in air volume by widening a control interval of the air volume control door because the first-stage air volume can be realized even though the air volume control door closes one of the air passageways, and reducing a whistle noise by securing a predetermined cross-sectional area of the air passageway through the bypass passageways even though the cross-sectional area of the air passageway gets narrower while the air volume control door closes one of the air passageways.

The invention discloses an air conditioner and a constant-air-volume control method, a control device and a control system of an indoor fan thereof. The constant-air-volume control method of the indoor fan of the air conditioner comprises the steps of: obtaining an air pressure characteristic curve and an initial air volume Q1 of the indoor fan under a D air gear; acquiring present operation parameters of the indoor fan under the D air gear; solving a present air volume Qn under the D air gear according to the present operation parameters and the air pressure characteristic curve; calculating change values of the initial air volume Q1 under the D air gear and the present air volume Qn; adopting an optimizing algorithm to determine a constant-air air gear matched with the initial air volume Q1 when the change values reach preset thresholds; and actuating an air gear adjusting instruction to adjust the indoor fan to the constant-air air gear. The air conditioner and the constant-air-volume control method, control device and control system of the indoor fan thereof can realize real-time air volume and the initial air volume of the indoor fan to approximate to or even achieve the effect of constant air volume as far as possible, have no need to adopt a constant-air-volume motor, are low in cost, and guarantee the use comfort of the air conditioner.