Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
  • F25B47/02—Defrosting cycles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F11/00—Control or safety arrangements
  • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
  • F24F11/41—Defrosting; Preventing freezing
  • F24F11/42—Defrosting; Preventing freezing of outdoor units
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B13/00—Compression machines, plants or systems, with reversible cycle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
  • F25B2313/029—Control issues
  • F25B2313/0294—Control issues related to the outdoor fan, e.g. controlling speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2500/00—Problems to be solved
  • F25B2500/12—Sound
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2600/00—Control issues
  • F25B2600/23—Time delays
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2106—Temperatures of fresh outdoor air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2117—Temperatures of an evaporator

Definitions

• the present invention relates to an outdoor unit of an air conditioner that includes an outdoor fan that accelerates heat exchange by applying air to an outdoor heat exchanger, and controls the rotation speed of the outdoor fan when the outdoor heat exchanger is frosted.
• the subject of this invention is providing the outdoor unit of the air conditioning apparatus which can suppress the ventilation sound of the fan which does not reduce driving
• An outdoor unit is an outdoor unit of an air conditioner to which the indoor unit is connected, and includes an outdoor heat exchanger, an outdoor fan, and a control unit.
• the outdoor heat exchanger exchanges heat with air as an evaporator during heating operation.
• the outdoor fan generates an air flow that passes through the outdoor heat transfer surface.
• the controller detects or estimates frost formation on the outdoor heat exchanger. When it is, the fan control at the time of frost formation is performed to reduce the rotation speed of the outdoor fan. In this outdoor unit, even if the ventilation resistance increases due to frost formation, the increase amount of the blowing sound is small. For this reason, unpleasant noise is suppressed.
• An outdoor unit according to a second aspect of the present invention is the outdoor unit according to the first aspect of the present invention, and the frosting fan control is not executed until a predetermined time has elapsed for the heating operation start force.
• the heating operation is maintained for a predetermined time, even if the operation is started with low outside air, it is possible to provide warm air.
• An outdoor unit according to a third aspect of the present invention is the outdoor unit according to the first aspect of the present invention, and the fan control at the time of frost formation includes reducing a preset target rotational speed of the outdoor fan.
• An outdoor unit according to a fourth aspect of the present invention is the outdoor unit according to the first aspect of the present invention, and the frosting fan control includes lowering an upper limit of an input value supplied to the outdoor fan. .
• An outdoor unit according to a fifth aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein a predetermined time has elapsed since the start of heating operation, and the evaporating temperature of the outdoor heat exchanger has fallen below a predetermined temperature. Fan control is executed.
• frost formation is detected without using a special device, and blowing noise is suppressed.
• An outdoor unit according to a sixth aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein a predetermined time has elapsed since the start of heating operation and the outside air temperature has fallen below a predetermined temperature, fan control during frost formation Is executed.
• the outdoor unit according to the seventh aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein the frosting fan control is executed when a predetermined time has elapsed from the start of the heating operation and the low pressure side falls below a predetermined pressure. .
• the outdoor unit according to the eighth aspect of the invention is the outdoor unit according to the first aspect of the invention, and is When the fixed time has elapsed and the on-time ratio in one cycle of the drive voltage supplied to the outdoor fan exceeds the preset on-time ratio, fan control during frost formation is executed.
• frost formation is detected without using a special device, and blowing noise is suppressed.
• An outdoor unit according to a ninth aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein a predetermined time has elapsed from the start of heating operation, and the rotational speed of the outdoor fan is less than a preset target rotational speed. At that time, fan control during frost formation is executed.
• An outdoor unit according to a tenth aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein an average value of inputs supplied to the outdoor fan is calculated before the start of frost fan control, While the fan control is being executed, the average value of the input calculated previously is supplied to the outdoor fan.
• An outdoor unit according to an eleventh aspect of the present invention is the outdoor unit according to the first aspect of the present invention, wherein when the frosting fan control is performed, the rotational speed of the outdoor fan is preset. If it falls below, start defrosting operation.
• An outdoor unit is the outdoor unit according to the first aspect of the present invention, wherein the number of rotations of the outdoor fan and the number of rotations of the outdoor fan before frosting are determined when fan control is performed during frost formation. If the difference exceeds the preset tolerance, start defrosting operation.
• the heating capacity decreases due to fan control during frost formation, so the difference between the rotation speed of the outdoor fan and the rotation speed of the outdoor fan before frost formation is monitored, and the heating capacity exceeds the allowable range. To prevent it from falling. For this reason, the defrosting operation will be started in a timely manner when frosting has progressed to such an extent that the increase in blowing noise cannot be suppressed. Heating performance recovers before starting.
• An outdoor unit is the outdoor unit according to the first aspect of the present invention, wherein the rotation speed of the outdoor fan and the rotation of the outdoor fan before frost formation are performed when fan control is performed during frost formation.
• the defrosting operation is started.
• the heating capacity decreases due to fan control during frost formation, so the integrated value of the difference between the rotation speed of the outdoor fan before frost formation and the current rotation speed is monitored, and the heating capacity is within the allowable range. It is prevented from falling over.
• the defrosting operation is started in a timely manner, so that the heating performance is restored before the user feels that heating is insufficient.
• the start of the defrosting operation is determined based on the integrated value of the rotational speed difference, even if a sudden back wind acts on the outdoor fan and the rotational speed suddenly drops, or the power supply voltage drops. However, even if the rotational speed of the outdoor fan drops suddenly, the defrosting operation will not be started by mistake.
• the heating operation is maintained for a predetermined time, so that warm air can be provided even when the operation is started with low outside air.
• frost formation is detected without using a special device, and blowing noise is suppressed.
• the outdoor unit according to the tenth aspect of the invention automatically reduces the rotational speed of the outdoor fan due to ventilation resistance due to frost formation. For this reason, the increase amount of blowing sound is small.
• the defrosting operation is started in a timely manner when the frosting progresses to such an extent that the increase in the blowing noise cannot be suppressed. Therefore, before the user feels insufficient heating. Heating performance is restored.
• FIG. 1 is a refrigerant circuit of an air conditioner including an outdoor unit according to an embodiment of the present invention.
• Figure 2 Control block diagram of the air conditioner including the outdoor unit
• FIG. 3 is a graph showing the relationship between outdoor fan input, outdoor fan rotation speed, and outdoor fan blowing sound when normal control is performed during frost formation.
• FIG. 4 is a graph showing the relationship between outdoor fan input, outdoor fan rotation speed, and outdoor fan blowing sound when fan control is performed during frost formation.
• FIG. 5 is a flowchart of fan control during frost formation.
• FIG. 6 is a graph showing the relationship between outdoor fan input, outdoor fan rotation speed, outdoor fan blowing sound, and frost formation when fan control during frost formation is continued.
• FIG. 7 Fan control start force during frost formation Flow chart until defrost control starts.
• FIG. 8 is a flowchart up to the start of defrosting control of the fan control start force during frosting of the outdoor unit according to the first modification of the embodiment of the present invention.
• FIG. 9 is a flowchart up to the start of defrosting control of the fan control start force during frost formation of the outdoor unit according to the second modification of the embodiment of the present invention.
• FIG. 1 shows a refrigerant circuit of an air conditioner including an outdoor unit according to an embodiment of the present invention.
• the air conditioner 1 is a multi-room air conditioner, and has a configuration in which a plurality of indoor units 3 are connected in parallel to a single outdoor unit 2.
• the refrigerant circuit 10 of the air conditioner 1 is mainly composed of a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an expansion valve 14, and an indoor heat exchanger 16 connected in this order. It is a cycle.
• the compressor 11 is a variable capacity inverter compressor that performs rotational speed control by an inverter.
• an accumulator 2 that separates liquid refrigerant and gas refrigerant is provided on the suction pipe side of the compressor 11. 0 is provided.
• the compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13 and the expansion valve 14 are included in the outdoor unit 2, and the indoor heat exchanger 16 is included in the indoor unit 3.
• the four-way switching valve 12 and the indoor heat exchanger 16 are connected by a refrigerant communication pipe 17a, and the expansion valve 14 and the indoor heat exchanger 16 are connected by a refrigerant communication pipe 17b.
• the refrigerant communication pipes 17a and 17b are arranged between the outdoor unit 2 and the indoor unit 3.
• the internal refrigerant circuit of the outdoor unit 2 is provided with a gas side closing valve 18 and a liquid side closing valve 19.
• the gas side closing valve 18 is arranged on the four-way switching valve 12 side, and the liquid side closing valve 19 is arranged on the expansion valve 14 side.
• a refrigerant communication pipe 17a is connected to the gas side closing valve 18, and a refrigerant communication pipe 17b is connected to the liquid side closing valve 19. These closing valves 18 and 19 are closed when the outdoor unit 2 and the indoor unit 3 are installed. The closing valves 18 and 19 are opened after the outdoor unit 2 and the indoor unit 3 are installed on the site and the refrigerant communication pipe 17a and the refrigerant communication pipe 17b are connected to the closing valves 18 and 19, respectively.
• the outdoor unit 2 is provided with an outdoor fan 29 for generating an air flow in order to promote heat exchange between the air and the outdoor heat exchanger 13.
• the air conditioner 1 including the outdoor unit 2 of the present embodiment includes a number of temperature sensors that are thermistors.
• the outdoor temperature sensor 102 detects the ambient temperature where the outdoor unit 2 is installed, and the discharge pipe temperature sensor 111 is attached to the discharge pipe of the compressor 11 and detects the discharge pipe temperature To.
• the evaporating temperature sensor 113 during heating operation is attached to the outdoor heat exchanger 13 to detect the evaporating temperature Te, and the liquid pipe temperature sensor 117 is attached to the outlet side during heating operation of the indoor heat exchanger 16 to Detect tube temperature T1.
• a low pressure side pressure sensor 213 for detecting a low pressure side pressure is provided between the four-way switching valve 12 and the outdoor heat exchanger 13. Based on the detected values of the temperature sensor and the detected value of the pressure sensor, the control unit 4 controls the operation of the air conditioner 1.
• the four-way switching valve 12 is maintained in the state indicated by the solid line in FIG.
• the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 13 through the four-way selector valve 12, and the outdoor air Exchange heat and condense.
• the liquefied refrigerant is depressurized to a predetermined low pressure by the expansion valve 14 and is further evaporated by exchanging heat with room air by heat exchange in the room.
• the indoor air cooled by the evaporation of the refrigerant is blown out into the room by an indoor fan (not shown) to cool the room.
• the refrigerant evaporated and vaporized in the indoor heat exchanger 16 returns to the outdoor unit 2 through the refrigerant communication pipe 17a, and is sucked into the compressor 11.
• the four-way selector valve 12 is held in the state indicated by the broken line in FIG.
• the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the indoor heat exchange of each indoor unit 3 through the four-way switching valve 12, and exchanges heat with the indoor air to condense and liquidate. .
• the indoor air heated by the condensation of the refrigerant is blown out into the room by the indoor fan to heat the room.
• the refrigerant liquefied in the indoor heat exchanger 16 returns to the outdoor unit 2 through the refrigerant communication pipe 17b.
• the refrigerant that has returned to the outdoor unit 2 is decompressed to a predetermined low pressure by the expansion valve 14, and is further evaporated by exchanging heat with outdoor air in the outdoor heat exchanger 13.
• the refrigerant evaporated and evaporated in the outdoor heat exchanger 13 is sucked into the compressor 11 through the four-way switching valve 12.
• the outdoor fan 29 includes a motor 29a.
• the motor 29a is a long-life DC brushless motor, and the number of revolutions can be changed by controlling the ON time ratio (DUTY ratio) during one cycle of power input (DUTY control).
• the rotational speed is detected by a rotational speed sensor 129 that is provided in the motor 29a and is a Hall IC.
• the rotational speed of the outdoor fan 29 decreases. This rotational speed decrease is detected by the rotational speed sensor 129. Further, as the duty ratio is increased, the input supplied to the motor 29a of the outdoor fan 29 increases, so the rotational speed of the outdoor fan 29 increases.
• Fig. 3 is a graph showing ⁇ Relationship between outdoor fan input, outdoor fan rotation speed, and outdoor fan blowing sound under normal control during frost formation '', and the horizontal axis is the elapsed time after the start of heating operation. The vertical axis shows the outdoor fan input, outdoor fan speed, and outdoor fan blowing sound in descending order. Show.
• the frost starts to increase and the draft resistance starts to increase.
• the outdoor fan input is increased to keep the rotational speed of the outdoor fan 29 constant so that the rotational speed does not drop due to draft resistance. For this reason, ventilation sound increases rapidly.
• FIG. 2 is a control block diagram of the air conditioner 1 including the outdoor unit 2 of the present embodiment.
• the control unit 4 receives detection values from the outdoor temperature sensor 102, the evaporation temperature sensor 113, the outdoor fan rotation speed sensor 129, and the low pressure side pressure sensor 213 through the frost detection unit 41, and performs outdoor heat exchange.
• the outdoor fan 29 is controlled via the outdoor fan control unit 42 by detecting or estimating the frost formation of the vessel 13.
• control unit 4 keeps the outdoor fan input constant when the frosting of the outdoor heat exchanger 13 starts and the ventilation resistance starts to increase, and the outdoor fan speed is reduced. I try to go down. This is fan control at the time of frost formation, and this suppresses the increase of the blowing sound.
• FIG. 4 is a graph showing “relationship between outdoor fan input, outdoor fan rotation speed, and outdoor fan blowing sound when fan control is performed during frost formation”, and the horizontal axis indicates the start of heating operation. The elapsed time is shown, and the vertical axis shows the outdoor fan input, outdoor fan rotation speed, and outdoor fan blowing sound in order from the bottom.
• the heating operation is started and the predetermined time TD is passed, frosting of the outdoor heat exchanger 13 starts and the ventilation resistance starts to increase.
• the outdoor fan input is kept constant, the rotational speed of the outdoor fan 29 naturally decreases due to the ventilation resistance, and the increase in the blowing noise becomes smaller than when the normal control is maintained.
• FIG. 5 is a flowchart of fan control during frost formation.
• the heating operation is started, the elapsed time TD after the heating operation is started in S1.
• TD2 After waiting for a certain time (TD2) in S2, it is determined in S3 whether or not the outside air temperature is lower than a predetermined temperature (Doadef). If Yes, the average value of the outdoor fan input is calculated in S4. Then, the process proceeds to S5, in which it is determined whether or not the time TD that has elapsed since the start of timekeeping has reached the predetermined time (TD1). Determine whether the temperature is lower than Tedef. If S6 is Yes, proceed to S7 so that the average value of the input calculated by the outdoor fan input force S4 is maintained. If any of S3, S5, and S6 is No, the system enters normal operation.
• S1 to S7 are the conditions for starting fan control during frost formation, and S7 is the fan control operation during frost formation.
• FIG. 6 is a graph showing the relationship between the outdoor fan input, the outdoor fan rotation speed, the outdoor fan blowing sound, and the amount of frost formation when the fan control during frost formation is continued. As shown in Fig. 6, if the amount of frost formation increases excessively, even if the rotational speed of the outdoor fan 29 continues to decrease, the amount of increase in the blowing noise increases, and the blowing noise finally reaches the allowable limit value Qs. To reach. The rotation speed of the outdoor fan 29 at this time is defined as the lower limit rotation speed Ns.
• the defrosting control is executed.
• the control unit 4 performs fan control during frost formation
• the frost formation amount increases. It is determined that the blowing sound has reached the allowable limit value Qs, and the fan control during frost formation is switched to defrost control.
• FIG. 7 is a flowchart from the start of fan control during frost formation to the start of defrost control.
• the control unit 4 keeps the input to the outdoor fan 29 constant at step S11.
• step S12 the rotational speed N of the outdoor fan 29 is detected.
• step S13 it is determined whether or not the rotational speed N of the outdoor fan 29 has fallen below the lower limit rotational speed Ns. When it determines with Yes at step S13, it switches to defrost control at step S14. No in step S13 If set, return to step S12.
• FIG. 8 is a flowchart from the start of fan control during frost formation to the start of defrost control of the outdoor unit according to the first modification of the embodiment of the present invention.
• the control unit 4 keeps the input to the outdoor fan 29 constant at step S21.
• step S22 the rotational speed Na of the outdoor fan 29 before frost formation is stored.
• step S23 the rotational speed N of the outdoor fan 29 is detected.
• step S24 it is determined whether or not the difference (Na ⁇ N) between the rotational speed Na of the outdoor fan 29 before frost formation and the detected rotational speed N of the outdoor fan 29 exceeds an allowable value L. If YES in step S24, switch to defrost control in step S25. If it is determined No in step S24, the process returns to step S23.
• the first modification since it is determined to switch to defrost control based on the instantaneous rotational speed of the outdoor fan 29, for example, natural wind against the air blowing direction of the outdoor fan 29 hits the outdoor fan 29 and rotates. If the number decreases instantaneously, or if the power supply voltage decreases and the rotational speed of the outdoor fan 29 decreases instantaneously, there is a possibility of erroneously switching to defrost control. Therefore, in the second modification, switching to defrosting control is performed when the integrated value of the difference from the rotational speed of the outdoor fan 29 before frosting exceeds the allowable volume calculation value.
• FIG. 9 is a flowchart from the start of fan control during frost formation to the start of defrost control of the outdoor unit according to the second modification of the embodiment of the present invention.
• the control unit 4 performs step S3. 1 keeps the input to the outdoor fan 29 constant.
• step S32 the rotational speed Na of the outdoor fan 29 before frost formation is stored.
• step S33 the rotational speed Ni of the outdoor fan 29 is detected i times (for example, 5 times) every t seconds (for example, 60 seconds).
• step S34 it is determined whether the integrated value ⁇ (Na — Ni) of the difference between the rotational speed Na of the outdoor fan 29 before frost formation and each detected rotational speed of the outdoor fan 29 exceeds the allowable integrated value M. judge. If it is determined as Yes in step S34, switch to defrost control in step S35. If it is determined No in step S34, return to step S33.
• the outdoor unit 2 includes an outdoor heat exchanger 13, an outdoor fan 29, and a control unit 4.
• the outdoor heat exchanger 13 exchanges heat with air as an evaporator during heating operation.
• the outdoor fan 29 generates an air flow passing through the outdoor heat exchange surface.
• the control unit 4 performs frost formation fan control for reducing the rotation speed of the outdoor fan 29. For this reason, even if ventilation resistance increases due to frost formation, unpleasant noise is suppressed because the amount of increase in blowing noise is small.
• the fan control during frost formation is not executed until the heating operation start force predetermined time elapses. For this reason, since the heating operation is maintained for a predetermined time, even if the operation is started with low outside air, warm air is provided.
• the fan control at the time of frost formation of the outdoor unit 2 includes lowering the target rotational speed of the outdoor fan 29 set in advance. Alternatively, it includes lowering the upper limit of the input value supplied to the outdoor fan 29. As a result, the rotational speed of the outdoor fan 29 decreases during frost formation, and the amount of increase in the blowing sound is reduced. For this reason, noise is suppressed.
• the frosting fan control is executed when a predetermined time elapses in the heating operation start force and the evaporation temperature of the outdoor heat exchange is lower than the predetermined temperature.
• a predetermined time has elapsed from the start of heating operation and the outside air temperature falls below a predetermined temperature
• fan control during frost formation is executed.
• the frosting fan control is executed.
• the frosting fan control is executed when the heating operation start force has also passed the predetermined time and the outdoor fan speed falls below a preset target speed. For this reason, frost formation is detected without using a special device, and blowing noise is suppressed.
• the average value of the input supplied to the outdoor fan 29 is calculated before the start of frost fan control, and while the frost fan control is being executed, the outdoor fan To 29, the average value of the previously calculated input is supplied.
• the rotational speed of the outdoor fan 29 is automatically reduced by the draft resistance due to frost formation. For this reason, the increase amount of blowing sound becomes small.
• the defrosting operation is started when the rotation speed of the outdoor fan falls below the lower limit rotation speed Ns during fan control during frost formation.
• the fan control during frosting reduces the heating capacity, so the outdoor fan speed is monitored to prevent the heating capacity from falling beyond the allowable range.
• the defrosting operation is started in a timely manner, so that the heating performance is restored before the user feels that heating is insufficient.
• defrosting occurs when the integrated value of the difference between the rotational speed of the outdoor fan 29 and the rotational speed of the outdoor fan 29 before frost exceeds the allowable integrated value M. You may start driving. As a result, even if a sudden back wind acts on the outdoor fan and its rotation speed suddenly decreases, or even if the power supply voltage decreases and the outdoor fan rotation speed suddenly decreases, the defrosting operation is mistakenly performed. Will never start.
• the outdoor unit according to the present invention generates a low noise from the outdoor fan during frost formation. It is effective as an outdoor unit for an air conditioner.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Air Conditioning Control Device (AREA)

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• 2006
  • 2006-12-22 JP JP2006345396A patent/JP4270274B2/ja not_active Expired - Fee Related
• 2007
  • 2007-03-29 AU AU2007232984A patent/AU2007232984B2/en not_active Ceased
  • 2007-03-29 WO PCT/JP2007/056847 patent/WO2007114243A1/ja active Application Filing
  • 2007-03-29 EP EP07740285A patent/EP2012078A4/de not_active Withdrawn

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