JP6440930B2 - Air conditioner and control method of air conditioner - Google Patents

Description

  The present invention relates to an air conditioner and an air conditioner control method.

  If the air conditioner is stopped for a long time, the refrigerant becomes liquid and accumulates in the compressor. If the compressor is started in this state, the compressor may be damaged by liquid compression. For this reason, particularly in an air conditioner for cold regions, a crankcase heater is attached to the compressor, and before the air conditioner is operated, the crankcase heater is energized to heat the compressor, thereby collecting liquid refrigerant. This prevents liquid compression due to intrusion.

  However, if the crankcase heater is energized continuously while the compressor is stopped, the power consumption of the crankcase heater increases and the standby power of the air conditioner increases.

  In order to solve this problem, Patent Document 1 discloses that after the crankcase heater is operated when the compressor is in a stopped state, the operation of the crankcase heater is stopped when the refrigeration oil temperature exceeds a predetermined temperature. An air conditioner prepared for restarting the compressor is described.

Japanese Patent No. 3799940

  However, in the air conditioner described in Patent Document 1, it is necessary to repeatedly energize the crankcase heater every time the refrigeration oil temperature becomes lower than a predetermined temperature when the compressor is stopped, and the reduction in standby power is limited. there were.

  The present invention has been made in view of such circumstances, and an air conditioner and an air conditioner that can further reduce standby power generated by energizing a crankcase heater during a period in which the compressor is stopped. It aims at providing the control method of a machine.

  In order to solve the above problems, the air conditioner and the air conditioner control method of the present invention employ the following means.

In the first aspect of the present invention, a crankcase heater is attached to the compressor, the compressor can be heated by energizing the crankcase heater, and the compressor is started according to a predetermined schedule. In the air conditioner, the energization time of the crankcase heater is calculated based on the superheat degree of the refrigerant and the outside air temperature before the compressor is started in the period when the compressor is stopped. Control means for determining a timing for starting energization of the crankcase heater from the energization time of the crankcase heater and the schedule, and the control means repeatedly calculates the energization time until the timing is reached. An air conditioner is provided that repeats the determination of the new timing.

  According to this configuration, in the air conditioner, the crankcase heater is attached to the compressor, and the compressor can be heated by energizing the crankcase heater. The air conditioner heats the compressor by energizing the crankcase heater before starting the stopped compressor. Thereby, since the liquid refrigerant is heated and vaporized, liquid compression due to the accumulation of the liquid refrigerant is prevented.

However, unless energization of the crankcase heater is started at an appropriate timing, energization of the crankcase heater is performed more than necessary, and standby power increases.
Therefore, the timing for starting energization of the crankcase heater is determined based on the superheat degree of the refrigerant and the outside air temperature before the compressor is started in the period in which the compressor is stopped. That is, the timing for starting energization of the crankcase heater is determined so that the parameter reaches a predetermined target value at the time when the compressor starts to start.
Specifically, the lower the degree of superheat of the refrigerant, the earlier the timing of starting energization of the crankcase heater so that the temperature of the refrigerant reaches a temperature at which accumulation can be eliminated at the start of operation of the compressor. On the other hand, the higher the degree of superheat of the refrigerant, the later the timing for starting energization of the crankcase heater. Thereby, it is suppressed that the energization time of a crankcase heater becomes longer than necessary.

  The accumulation of liquid refrigerant is small when the degree of superheat is sufficiently high. Also, if the lower temperature of the compressor is sufficiently high, the liquid refrigerant will not accumulate. However, the lower temperature of the compressor is easily affected by the outside air temperature, and the state of the refrigerant is not necessarily measured correctly. On the other hand, the degree of superheat of the refrigerant is a parameter correlated with not only the temperature of the refrigerant but also the pressure of the refrigerant. For this reason, the measurement of the superheat degree of the refrigerant measures the state of the refrigerant more correctly than the measurement of the lower temperature of the compressor. Therefore, the timing for starting energization of the crankcase heater can be determined more accurately by using the degree of superheat.
  Even if the crankcase heater is energized, the degree of increase in the compressor temperature, that is, the refrigerant temperature, varies depending on the difference in the outside air temperature. Therefore, in this configuration, the energization time of the crankcase heater is calculated using not only the degree of superheat but also the outside air temperature, and the timing for starting energization is determined. That is, even when the parameter values are the same, the lower the outside air temperature, the earlier the timing for starting energization of the crankcase heater, and the higher the outside air temperature, the later the timing for starting energization of the crankcase heater. Thereby, the timing which supplies with electricity to a crankcase heater can be determined more correctly. Therefore, according to this configuration, standby power generated by energizing the crankcase heater can be further reduced while the compressor is stopped.

In the first aspect, the table示灯is provided on the control board, the indicator light, when the state free operation of the remote control has continued for a predetermined time or more, or, if the capacity of the outdoor unit does not change more than a predetermined time, or It is preferable to turn off the light when there is no change in starting and stopping of the compressor for a predetermined time or more .

  This configuration can further reduce the power consumption of the air conditioner.

The second condition like the present invention, the crank case heater is attached to the compressor, wherein the compressor is configured to be heated by energizing the crankcase heater, the line according to the schedule start of the compressor is predetermined a crack Ru control method of an air conditioner, the before said compressor is a period that is stopped compressor is started, based on parameters that correlate to the temperature of the refrigerant, the crankcase Calculate the energization time of the heater, determine the timing for starting energization of the crankcase heater from the calculated energization time of the crankcase heater and the schedule, and repeat the calculation of the energization time until the timing is reached An air conditioner control method is provided that repeats the determination of the new timing .

  According to the present invention, there is an excellent effect that standby power generated by energizing the crankcase heater can be further reduced during a period in which the compressor is stopped.

It is a schematic block diagram of the multi air conditioner which concerns on 1st Embodiment of this invention. It is a block diagram around the compressor provided with the crankcase heater of the multi air conditioner which concerns on 1st Embodiment of this invention. It is a graph which shows the relationship between the superheat degree which concerns on 1st Embodiment of this invention, and heater ON time. It is a flowchart which shows the flow of CH energization processing concerning a 1st embodiment of the present invention. It is a graph which shows the relationship between the superheat degree which concerns on 2nd Embodiment of this invention, and heater ON time.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of an air conditioner and an air conditioner control method according to the present invention will be described with reference to the drawings.

[First Embodiment]
The first embodiment of the present invention will be described below.
FIG. 1 shows a schematic configuration diagram of a multi-air conditioner according to the first embodiment of the present invention, and FIG. 2 shows a configuration diagram around a compressor provided with the crankcase heater.
The multi-type air conditioner 1 has a branching unit 6 between a gas side pipe 4 and a liquid side pipe 5 from which a plurality of indoor units 3A and 3B are led out from the outdoor unit 2 with respect to one outdoor unit 2. Are connected to each other in parallel.

  The outdoor unit 2 heats an inverter-driven compressor 10 that compresses refrigerant, an oil separator 11 that separates lubricating oil from refrigerant gas, a four-way switching valve 12 that switches the circulation direction of refrigerant, and refrigerant and outside air. The outdoor heat exchanger 13 to be exchanged, the supercooling coil 14 configured integrally with the outdoor heat exchanger 13, the outdoor expansion valve (EEVH) 15, the receiver 16 storing the liquid refrigerant, and the liquid refrigerant A subcooling heat exchanger 17 that provides supercooling, a supercooling expansion valve (EEVSC) 18 that controls the amount of refrigerant that is diverted to the subcooling heat exchanger 17, and a liquid component from the refrigerant gas that is drawn into the compressor 10. And an accumulator 19 that sucks only the gas component to the compressor 10 side, a gas side operation valve 20, and a liquid side operation valve 21.

  Each said apparatus by the side of the outdoor unit 2 is connected as is well-known via the refrigerant | coolant piping 22, and comprises the outdoor side refrigerant circuit 23. FIG. The outdoor unit 2 is provided with an outdoor fan 24 that ventilates the outdoor air to the outdoor heat exchanger 13, and the oil separator 11 is interposed between the oil separator 11 and the suction pipe of the compressor 10. An oil return circuit 25 is provided for returning the lubricating oil separated from the discharged refrigerant gas to the compressor 10 by a predetermined amount.

  The gas side pipe 4 and the liquid side pipe 5 are refrigerant pipes connected to the gas side operation valve 20 and the liquid side operation valve 21 of the outdoor unit 2, and are connected to the outdoor unit 2 and to it during installation on site. The pipe length is set according to the distance between the plurality of indoor units 3A and 3B. An appropriate number of branching devices 6 are provided in the middle of the gas side piping 4 and the liquid side piping 5, and an appropriate number of indoor units 3 </ b> A and 3 </ b> B are connected via the branching devices 6. As a result, a sealed refrigeration cycle (refrigerant circuit) 7 is configured.

  The indoor units 3A and 3B include an indoor heat exchanger 30 that exchanges heat between indoor air and refrigerant for indoor air conditioning, an indoor expansion valve (EEVC) 31, and an indoor air that circulates indoor air to the indoor heat exchanger 30. The fan 32 is provided, and is connected to the branching device 6 via the indoor branch gas side pipes 4A and 4B and the branch liquid side pipes 5A and 5B.

  Further, the pressure of the refrigerant discharged from the compressor 10 is measured by the pressure sensor 33.

In the air conditioner 1 described above, the cooling operation is performed as follows.
The high-temperature and high-pressure refrigerant gas compressed and discharged by the compressor 10 is separated from the lubricating oil contained in the refrigerant by the oil separator 11. Thereafter, the refrigerant gas is circulated to the outdoor heat exchanger 13 side by the four-way switching valve 12, and heat is exchanged with the outdoor air blown by the outdoor fan 24 in the outdoor heat exchanger 13 to be condensed and liquefied. The liquid refrigerant is further cooled by the supercooling coil 14, passes through the outdoor expansion valve 15, and is temporarily stored in the receiver 16.

  The liquid refrigerant whose circulation amount is adjusted by the receiver 16 is diverted from the liquid refrigerant pipe in the process of flowing through the liquid refrigerant pipe side through the supercooling heat exchanger 17 and is insulated by the supercooling expansion valve (EEVSC) 18. Heat exchange is performed with a part of the expanded refrigerant to provide a degree of supercooling. The liquid refrigerant is led out from the outdoor unit 2 to the liquid side pipe 5 through the liquid side operation valve 21. Furthermore, the liquid refrigerant led out to the liquid side pipe 5 is diverted to the branch liquid side pipes 5A and 5B of the indoor units 3A and 3B via the branching unit 6.

  The liquid refrigerant divided into the branch liquid side pipes 5A and 5B flows into the indoor units 3A and 3B, is adiabatically expanded by the indoor side expansion valve (EEVC) 31, and becomes a gas-liquid two-phase flow. 30. In the indoor heat exchanger 30, the indoor air circulated by the indoor fan 32 and the refrigerant are heat-exchanged, and the indoor air is cooled and supplied to the indoor cooling. On the other hand, the refrigerant is gasified, reaches the branching device 6 through the branch gas side pipes 4A and 4B, and is merged with the refrigerant gas from the other indoor units in the gas side pipe 4.

  The refrigerant gas merged in the gas side pipe 4 returns to the outdoor unit 2 again, merges with the refrigerant gas from the supercooling heat exchanger 17 through the gas side operation valve 20 and the four-way switching valve 12, and then accumulator 19. To be introduced. In the accumulator 19, the liquid component contained in the refrigerant gas is separated, and only the gas component is sucked into the compressor 10. This refrigerant is compressed again in the compressor 10, and the cooling operation is performed by repeating the above cycle.

On the other hand, the heating operation is performed as follows.
The high-temperature and high-pressure refrigerant gas compressed and discharged by the compressor 10 is separated from the lubricating oil contained in the refrigerant by the oil separator 11 and then the gas-side operation valve 20 side through the four-way switching valve 12. It is circulated in. The refrigerant circulated to the gas-side operation valve 20 side is led out from the outdoor unit 2 through the gas-side pipe 4, and passes through the branching unit 6 and the indoor-side branching gas-side pipes 4A and 4B to be a plurality of indoor units 3A and 3B. To be introduced.

  The high-temperature and high-pressure refrigerant gas introduced into the indoor units 3A and 3B is heat-exchanged with the indoor air circulated through the indoor fan 32 in the indoor heat exchanger 30, and the indoor air is heated and used for indoor heating. The The liquid refrigerant condensed in the indoor heat exchanger 30 reaches the branching device 6 through the indoor expansion valve (EEVC) 31 and the branch liquid side pipes 5A and 5B, and is merged with the refrigerant from other indoor units. It returns to the outdoor unit 2 side through the liquid side pipe 5. During heating, in the indoor units 3A and 3B, the opening degree of the indoor expansion valve (EEVC) 31 is set so that the refrigerant outlet temperature or the refrigerant subcooling degree of the indoor heat exchanger 30 functioning as a condenser becomes a target value. Is to be controlled.

  The refrigerant that has returned to the outdoor unit 2 side reaches the supercooling heat exchanger 17 via the liquid side operation valve 21, and is given supercooling as in the case of cooling, and then flows into the receiver 16 and temporarily stored. Thus, the circulation amount is adjusted. The liquid refrigerant is supplied to the outdoor expansion valve (EEVH) 15 and subjected to adiabatic expansion, and then flows into the outdoor heat exchanger 13 through the supercooling coil 14.

  In the outdoor heat exchanger 13, heat is exchanged between the outside air blown through the outdoor fan 24 and the refrigerant, and the refrigerant absorbs heat from the outside air and is evaporated and gasified. The refrigerant is introduced from the outdoor heat exchanger 13 through the four-way switching valve 12 to the refrigerant gas from the supercooling heat exchanger 17 and then introduced into the accumulator 19. In the accumulator 19, the liquid component contained in the refrigerant gas is separated, and only the gas component is sucked into the compressor 10 and compressed again in the compressor 10. The heating operation is performed by repeating the above cycle.

  Further, in the air conditioner 1, the compressor 10 is provided with a crankcase heater (hereinafter referred to as “CH”) 40 on the outer periphery of the hermetic housing 10A as shown in FIG. In the CH 40, during the period when the compressor 10 is stopped, the refrigerant accumulates in the compressor 10 in a liquid state, and the compressor 10 sucks the liquid refrigerant when the compressor 10 starts up, causing liquid compression, and the compressor 10 is damaged. This is provided to prevent the liquid refrigerant from being discharged from the compressor 10 by energizing the CH 40 and heating the compressor 10 before the air conditioner 1 is operated. It is what you bear.

  The CH 40 is ON / OFF controlled for energization via the control unit 41. The control unit 41 calculates a normal operation mode control unit 42 that constantly controls energization based on a predetermined specification for the CH 40 while the compressor 10 is stopped, calculates the ON timing of the CH 40, and turns the CH 40 ON / OFF. An operation reduction mode control unit 43 that performs OFF control is provided. The control unit 41 includes a switching unit 44 that can selectively switch the control mode to either the normal operation mode or the operation reduction mode. The switching unit 44 can be switched from the remote controller 45 side, for example. Composed.

  The control unit 41 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a computer-readable recording medium. A series of processes for realizing various functions is recorded on a recording medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized.

Moreover, the control part 41 is provided with the indicator lamp 50 which shows the control state of the air conditioner 1 on the control board. The indicator lamp 50 is required for maintenance of the air conditioner 1 or the like. The indicator lamp 50 is, for example, a 7-segment display, but is not limited thereto, and may be one or a plurality of LED lamps.
Further, the control unit 41 has a measured value by the under-dome temperature sensor 52 that measures the temperature of the lower portion of the compressor 10 (hereinafter referred to as “under-dome temperature”), a measured value by the outside air temperature sensor 46 that measures the outside air temperature, and A measurement value by the pressure sensor 33 is input.

  The normal operation mode control unit 42 always energizes the CH 40 while the compressor 10 is in the stop period and heats the compressor 10 by turning on the CH 40 when the CH 40 ON condition described in the spec is set. . In this case, when the compressor 10 is started, the CH 40 is turned off during the start-up, and when the compressor 10 is stopped, the CH 40 is always turned on during the stop period.

As described above, the air conditioner 1 heats the compressor 10 by energizing the CH 40 before starting the stopped compressor 10. Thereby, since the liquid refrigerant is heated and vaporized, liquid compression due to the accumulation of the liquid refrigerant is prevented.
However, unless energization of CH40 is started at an appropriate timing, energization of CH40 is performed more than necessary, and standby power increases.

  Therefore, the operation reduction mode control unit 43 according to the first embodiment is based on parameters correlated with the refrigerant temperature before the compressor 10 is started in the period in which the compressor 10 is stopped. Thus, the timing for starting energization of CH40 is determined. That is, the timing for starting energization of the CH 40 is determined so that the parameter reaches a predetermined target value at the time when the compressor 10 starts to start.

  Note that the parameter according to the first embodiment is the degree of superheat of the refrigerant. This is because the accumulation of liquid refrigerant is small when the degree of superheat is sufficiently high. The degree of superheat is calculated by subtracting the saturation temperature calculated based on the measured value of the pressure sensor 33 from the under-dome temperature measured by the under-dome temperature sensor 52.

Then, the operation reduction mode control unit 43 calculates the time for energizing the CH 40 from the relationship between the degree of superheat as shown in the graph of FIG. 3 and the ON time of the CH 40 (hereinafter referred to as “heater ON time”).
Specifically, the timing at which energization of the CH 40 is started earlier as the degree of superheat is lower so that the refrigerant reaches the degree of superheat at which accumulation can be eliminated at the start of operation of the compressor 10. On the other hand, the higher the degree of superheat, the later the timing for starting energization of CH40. Furthermore, when the degree of superheat is sufficiently high, the CH 40 is not energized while the compressor 10 is stopped.
Thereby, it is suppressed that the energization time of CH40 becomes longer than necessary.

Although the relationship between the degree of superheat and the heater ON time is expressed by the function f as shown in equation (1), the relationship may not be linear as shown in FIG.
Heater ON time = f (degree of superheat) (1)
The function f is determined in advance based on the heat capacity of the compressor 10, the output of the CH 40, the heat radiation from the compressor 10, and the like. In addition, the target value of the superheat degree which can start the compressor 10 is 10-15 degreeC, for example.

  The control unit 41 according to the first embodiment is a so-called schedule timer for starting and stopping the air conditioner 1, that is, starting and stopping various components such as the compressor 10 according to a predetermined schedule. It has the function of. When the schedule timer is set, the control unit 41 cuts unnecessary power for each component device according to the schedule timer and puts the air conditioner 1 into the sleep state during the stop period of the air conditioner 1.

  Then, the operation reduction mode control unit 43 calculates a time for energizing the CH 40 (hereinafter referred to as “CH energization start time”) according to the calculated heater ON time and schedule. For example, when the air conditioner 1 is started at 8:00 am by the schedule timer, if the heater ON time is calculated as 3 hours, the CH energization start time is 5:00 am.

Note that when the temperature under the dome is sufficiently high, the liquid refrigerant does not accumulate. For this reason, as shown in the equation (2), the operation reduction mode control unit 43 may calculate the heater ON time using a function of heater ON time = f (under-dome temperature).
However, the temperature under the dome is easily affected by the outside air temperature, and the state of the refrigerant is not always measured correctly. On the other hand, the degree of superheat of the refrigerant is a parameter correlated with not only the temperature of the refrigerant but also the pressure of the refrigerant. For this reason, the measurement of the superheat degree of the refrigerant measures the state of the refrigerant more correctly than the measurement of the lower temperature of the compressor.
Therefore, by using the degree of superheat as a parameter having a correlation with the refrigerant temperature, it is possible to more accurately determine the timing of energizing CH40.

  FIG. 4 is a period in which the compressor 10 is stopped and before the compressor 10 is started, the energization process to the CH 40 (hereinafter referred to as “CH energization process”) executed by the operation reduction mode control unit 43. ). Note that the CH energization process is executed during a period in which the compressor 10 is stopped.

  First, in step 100, the degree of superheat is calculated.

  In the next step 102, the heater ON time is calculated based on the calculated degree of superheat.

  In the next step 104, the CH energization start time is calculated based on the calculated heater ON time.

  In the next step 106, it is determined whether or not the current time has reached the CH energization start time. If the determination is affirmative, the process proceeds to step 108. If the determination is negative, the process returns to step 100.

  In step 108, energization of CH40 is started.

  When returning from step 106 to step 100, a new CH energization start time is calculated based on the newly calculated superheat degree and heater ON time.

Further, the control unit 41 according to the present embodiment turns off the indicator lamp 50 when the control is stable for a predetermined time or more. The case where the control is stable is, for example, a case where there is no operation on the remote controller 45, a case where there is no change in the capacity of the outdoor unit 2, or a case where there is no change in starting and stopping of the compressor 10. The indicator lamp 50 is turned off according to the schedule timer.
Thereby, the power consumption of the air conditioner 1 is further reduced.

As described above, in the air conditioner 1 according to the first embodiment, the CH 10 is attached to the compressor 10, and the compressor can be heated by energizing the CH 40. Then, the control unit 41 starts CH40 based on the degree of superheat that is a parameter correlated with the temperature of the refrigerant before the compressor 10 is started in the period in which the compressor 10 is stopped. Determine timing.
Therefore, the air conditioner 1 according to the first embodiment can further reduce standby power generated by energizing the CH 40 during the period in which the compressor 10 is stopped.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
The configuration of the air conditioner 1 according to the second embodiment is the same as the configuration of the air conditioner 1 according to the first embodiment shown in FIGS.

  Even if the CH 40 is energized during the period in which the compressor 10 is stopped and before the compressor 10 is started, the temperature of the compressor 10, that is, the degree of increase in the refrigerant temperature, depends on the difference in the outside air temperature. Come different.

Therefore, the operation reduction mode control unit 43 according to the second embodiment is a period during which the compressor 10 is stopped and before the compressor 10 is started, based on the degree of superheat and the outside air temperature. The timing for starting energization is determined.
That is, the heater ON time is expressed as shown in Equation (2).
Heater ON time = f (degree of superheat, outside air temperature) (2)

  FIG. 5 is a graph showing the relationship between the degree of superheat and the heater ON time according to the second embodiment. A solid line indicates a case where the outside air temperature is lower than that of the broken line. Thus, even if the value of the degree of superheat is the same, the timing for starting energization of CH40 is advanced as the outside air temperature is lower. In addition, the higher the outside air temperature, the later the timing for starting energization of CH40.

  Therefore, the air conditioner 1 according to the second embodiment can more accurately determine the timing of energizing the crankcase heater.

  As mentioned above, although this invention was demonstrated using said each embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention.

  The flow of CH energization processing described in the above embodiment is also an example, and unnecessary steps are deleted, new steps are added, or the processing order is changed within a range not departing from the gist of the present invention. May be.

DESCRIPTION OF SYMBOLS 1 Air conditioner 10 Compressor 40 Crankcase heater 41 Control part 50 Indicator light

Claims (3)

In an air conditioner, a crankcase heater is attached to the compressor, the compressor can be heated by energizing the crankcase heater, and the compressor is started according to a predetermined schedule.
The crankcase heater is calculated by calculating the energization time of the crankcase heater based on the degree of superheat and the outside air temperature of the refrigerant before the compressor is started during the period when the compressor is stopped. From the energization time and the schedule, comprising a control means for determining the timing to start energization of the crankcase heater,
The said control means is an air conditioner which repeats the calculation of the said energization time until it reaches the said timing, and repeats the determination of the said new timing. Table示灯is provided on the control board,
The indicator lamp is in a state where there is no operation on the remote control for a predetermined time or more, or when the capacity of the outdoor unit does not change for a predetermined time or the start and stop of the compressor is not changed for a predetermined time or more. If the air conditioner according to claim 1 Symbol placement extinguishes the indicator. A control method for an air conditioner in which a compressor is provided with a crankcase heater, the compressor can be heated by energizing the crankcase heater, and the compressor is started according to a predetermined schedule. And
Before the compressor is started in the period when the compressor is stopped, the energization time of the crankcase heater is calculated based on the superheat degree of the refrigerant and the outside air temperature ,
From the calculated energization time of the crankcase heater and the schedule, the timing for starting energization of the crankcase heater is determined,
A control method for an air conditioner in which the energization time is repeatedly calculated until the timing is reached, and the new timing is repeatedly determined.

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