JP2014194312A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the rotational speed of an outdoor fan in a heating operation to be performed after the end of a defrosting operation by determining whether a present status is a status in which defrosting can be easily started, and to reduce unnecessary power consumption of the outdoor fan.SOLUTION: If a heating operation is to resume after finishing a defrosting operation, a rotational speed B of an outdoor fan included in an outdoor heat exchanger is set according to whether heating operation time A of a previous heating operation just before starting the defrosting operation (time from start of the heating operation until start of the defrosting operation) is long or short.

Description

  The present invention relates to an air conditioner having a refrigeration cycle that can be switched between a cooling operation and a heating operation by a four-way valve, and more specifically, the rotational speed of an outdoor fan when the defrosting operation is ended and the heating operation is restarted. It is related with the technique which controls.

  A cooling / heating combined use air conditioner has a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected via a refrigerant pipe. The compressor → four-way valve → outdoor heat exchanger → expansion valve → indoor heat exchanger → four-way valve → compressed to the compressor, the outdoor heat exchanger acts as a condenser and the indoor heat exchanger acts as an evaporator.

  On the other hand, during the heating operation, the refrigerant is flowed to the compressor → four-way valve → indoor heat exchanger → expansion valve → outdoor heat exchanger → four-way valve → compressor. A heat exchanger acts as an evaporator. This switching between cooling and heating is performed by the control unit on the outdoor unit side based on an instruction from a remote controller or the like.

  In this way, during the heating operation, the outdoor heat exchanger acts as an evaporator, so if the heating operation is continued in an environment where the outside air temperature is low, the condensed water adhering to the outdoor heat exchanger is frozen and frosted. The phenomenon occurs. If it does so, the heat exchange rate of an outdoor heat exchanger will fall.

  Therefore, during the heating operation, the control unit on the outdoor unit side determines whether a predetermined defrosting operation start condition is satisfied, and performs the defrosting operation when the defrosting condition is satisfied. Yes. The defrosting operation start conditions include the outside air temperature, the outdoor heat exchanger temperature of the outdoor heat exchanger, the heating operation time, and the like.

  Usually, the defrosting operation is performed by switching the four-way valve to the cooling operation side as reverse defrosting. That is, during the defrosting operation, as in the cooling operation, the high-temperature and high-pressure refrigerant from the compressor is supplied to the outdoor heat exchanger, thereby increasing the temperature of the outdoor heat exchanger (outdoor heat exchange temperature). And the frost adhering to the outdoor heat exchanger is melted.

  During the defrosting operation, the control unit on the outdoor unit side monitors, for example, the outdoor heat exchange temperature Tc and the defrosting operation time RT, and the outdoor heat exchange temperature Tc reaches a predetermined release temperature (15 ° C. as an example). When the temperature rises or when the outdoor heat exchange temperature Tc does not rise to the release temperature and the defrosting operation time RT reaches the time-up time (15 minutes as an example), the defrosting operation is terminated and the heating operation is started. Let it resume.

  Since the indoor heating is interrupted during the defrosting operation, in the heating operation after the completion of the defrosting operation, the outdoor fan heats up with the maximum number of rotations of the outdoor fan to increase the evaporation temperature of the outdoor heat exchanger. As much as possible, it is difficult to enter the next defrosting operation.

  However, when high heating capacity is not required from the indoor unit side, it is not necessary to operate the outdoor fan at the maximum number of rotations, and power is wasted correspondingly.

  In Patent Document 1, in order to prevent the room temperature from decreasing during the defrosting operation, the next defrosting start time is predicted from the defrosting operation conditions performed in the past, and a predetermined time before the predicted time. In addition, it has been proposed to increase the heating capacity in advance by increasing the set temperature of the room temperature by a predetermined value and performing the heating operation.

  However, even in this case, when the heating capacity is increased in advance, the rotation speed of the outdoor fan is set to be higher than the rotation speed at the time of the heating operation so far, and extra power is consumed accordingly. It will be.

JP-A-4-257646

  Therefore, the problem of the present invention is to determine whether the air conditioner is likely to enter the defrosting operation, and by setting the rotation speed of the outdoor fan in the heating operation performed after the defrosting operation is completed, It is to reduce wasteful power consumption.

In order to solve the above problems, the present invention provides a refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected via a refrigerant pipe, and the refrigeration by the four-way valve. A control unit that reversibly switches the cycle between heating operation and cooling operation, and the control unit moves the four-way valve from the heating operation side to the cooling operation side under a predetermined defrosting operation start condition during the heating operation. The defrosting operation for removing frost attached to the outdoor heat exchanger is started, and after the defrosting operation is started, the defrosting operation is terminated under a predetermined defrosting operation release condition, and the four-way valve is cooled. In an air conditioner that performs control to switch from the operation side to the heating operation side and resume the heating operation,
The control unit stores the heating operation time A executed in the previous heating operation immediately before entering the defrosting operation when the defrosting operation is ended and the heating operation is restarted, and the outdoor heat exchanger is provided. The rotational speed B of the outdoor fan is set according to the length of the heating operation time A, and the heating operation is restarted.

  According to a preferred aspect of the present invention, the control unit has a reference time Th for determining whether the heating operation time A exceeds a predetermined time, and the heating operation time A is shorter than the reference time Th. If it is time, the rotational speed B of the outdoor fan is made larger than the rotational speed Bf at the time of the previous heating operation, and the heating operation time A is longer than the reference time Th, The rotational speed B of the outdoor fan is set to the same rotational speed as the rotational speed Bf in the previous heating operation or a lower rotational speed.

  According to the present invention, when the defrosting operation is terminated and the heating operation is restarted, the rotational speed B of the outdoor fan is determined according to the length of the heating operation time A performed in the previous heating operation immediately before entering the defrosting operation. Thus, as in the above-described conventional technology, the wasteful power consumption of the outdoor fan can be reduced compared to the case where the rotational speed of the outdoor fan is uniformly set to the maximum rotational speed during the heating operation after the completion of the defrosting operation. Can be reduced.

The schematic diagram which shows the refrigerating cycle with which the air conditioner of this invention is provided. The flowchart which shows the procedure which sets the rotation speed of the outdoor fan at the time of the heating operation after completion | finish of a defrost operation.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this.

  As shown in FIG. 1, the air conditioner according to this embodiment connects a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an expansion valve 14, an indoor heat exchanger 16, and an accumulator 17 via a refrigerant pipe. And a control unit 20 that controls the refrigeration cycle.

  The compressor 11 may be any of a rotary type, a scroll type, a constant speed type, and a variable speed type using an inverter, but a discharge temperature sensor for detecting the temperature of the discharge refrigerant is provided in the refrigerant discharge pipe 11a of the compressor 11. 111 is provided.

  The outdoor heat exchanger 13 includes an outdoor fan 131. The outdoor heat exchanger 13 includes an outdoor air temperature sensor 132 that detects an outdoor air temperature, and an outdoor air temperature that detects the temperature (outdoor heat exchange temperature) Tc of the outdoor heat exchanger. A heat exchanger temperature sensor 133 is provided. The outdoor heat exchanger temperature sensor 133 also serves as a sensor that detects the frosting state of the outdoor heat exchanger 13.

  The outdoor heat exchanger temperature sensor 133 is disposed at a position where the frosting state of the outdoor heat exchanger 13 can be detected in a path (refrigerant pipe) passed through the outdoor heat exchanger 13. The outdoor heat exchanger 13 may be provided with a sensor (not shown) for detecting the state of heat exchange. As the expansion valve 14, for example, an electronic expansion valve whose valve opening degree is controlled by a pulse motor is used.

  The indoor heat exchanger 16 includes an indoor fan 161. The indoor heat exchanger 16 is provided with a room temperature sensor 162 that detects the room temperature and an indoor heat exchanger temperature sensor 163 that detects the temperature of the indoor heat exchanger 16.

  The accumulator 17 is a gas-liquid separator, and separates the liquid refrigerant contained in the refrigerant returned from the outdoor heat exchanger 13 or the indoor heat exchanger 16 to the compressor 11 side via the low-pressure side refrigerant return pipe 171. . The gas-phase refrigerant separated from the liquid refrigerant is sucked into the compressor 11 through the refrigerant suction pipe 11b.

  The four-way valve 12 includes a first port 121 to which discharged refrigerant is supplied, a second port 122 to which the outdoor heat exchanger 13 is connected, a second port 123 to which the indoor heat exchanger 16 is connected, and an accumulator 17. 4 ports of the 4th port 124 to which the refrigerant | coolant return piping 171 to reach is connected are provided.

  During the cooling operation, the four-way valve 12 is switched as shown by the solid line in the figure, the first port 121 and the second port 122 are connected, and the third port 123 and the fourth port 124 are connected.

  Thereby, the refrigerant discharged from the compressor 11 circulates from the outdoor heat exchanger 13 → the expansion valve 14 → the indoor heat exchanger 16 → the refrigerant return pipe 171 → the accumulator 17 → the compressor 11, and the outdoor heat exchanger 13 is circulated. The condenser and the indoor heat exchanger 16 function as an evaporator.

  During the heating operation, the four-way valve 130 is switched as indicated by the chain line in the figure, and the first port 121 and the third port 123 are connected, and the second port 122 and the fourth port 124 are connected.

  As a result, the refrigerant discharged from the compressor 11 circulates from the indoor heat exchanger 16 → the expansion valve 14 → the outdoor heat exchanger 13 → the refrigerant return pipe 171 → the accumulator 17 → the compressor 11, and the indoor heat exchanger 210 is circulated. The condenser and the outdoor heat exchanger 140 function as an evaporator.

  The control unit 20 is preferably a microcomputer. The control unit 20 includes a timer 210 that measures the operation time of heating operation, cooling operation, defrosting operation, and the like.

  Signals are input to the control unit 20 from the discharge temperature sensor 111, the outside air temperature sensor 132, the outdoor heat exchange temperature sensor 133, the room temperature sensor 162, and the like, and the control unit 20 performs the defrosting operation based on these signals. Control necessary for the operation of the refrigeration cycle.

  Next, with reference to the flowchart of FIG. 2, about the procedure of setting the rotation speed of the outdoor fan 131 at the time of the heating operation after completion | finish of the defrost operation performed in this embodiment (henceforth "outdoor fan rotation speed"). explain.

  First, in step ST101, when the heating operation is performed, the outdoor fan rotation speed B is set to an initial value. In this embodiment, the outdoor fan 131 has a maximum rotation speed (upper limit value) of 1200 rpm, a minimum rotation speed (lower limit value) of 600 rpm, and a rotation speed per step for changing the rotation speed is 100 rpm. The initial value set in step ST101 is determined based on the outside air temperature at that time, the rotational speed of the compressor, and the like, and in this example, B = 700 rpm.

  As described above, after the outdoor fan rotation speed B is set to the initial value of 700 rpm, a heating operation instruction is received from a remote controller or the like, and in step ST102, the heating operation is started and the timer 210 is started. Then, the timing of the heating operation time A is started.

  Then, the control part 20 determines whether defrost operation is started by step ST103. For this defrosting start determination, for example, the outside air temperature To, the outdoor heat exchange temperature Tc, the room temperature Ti, and the like are used. As an example, the outside air temperature To ≦ −5 ° C. and the outdoor heat exchange temperature Tc ≦ −15 ° C. In this case, and / or when the room temperature Ti does not reach the set temperature even after a predetermined time has elapsed, the control unit 20 determines that defrosting has started (Yes).

  Then, in step ST104, the heating operation time A counted by the timer 210 is stored, and in step ST105, the four-way valve 12 is switched from the heating operation side to the cooling operation side, and the defrosting operation is started. During the defrosting operation, the indoor fan 161 is stopped on the indoor unit side so that the indoor temperature does not decrease.

  When the defrosting operation is started, the control unit 20 determines whether or not to end the defrosting operation in step ST106. In this embodiment, the outdoor heat exchange temperature Tc and the defrost operation time RT are used for the defrosting end determination, and the outdoor heat exchange temperature Tc rises to a predetermined release temperature (15 ° C. as an example). Alternatively, when the outdoor heat exchange temperature Tc does not rise to the release temperature and the defrosting operation time RT reaches the time-up time (for example, 15 minutes), the control unit 20 determines that the defrosting is finished (Yes). To do.

  As a result, the four-way valve 12 is switched from the cooling operation side to the heating operation side again, and the heating operation is resumed by returning to step ST102. However, the heating operation performed in the previous step ST102 is referred to as “previous heating operation”, In this embodiment, the heating operation resumed after the frost operation is set as “next heating operation”. In this embodiment, the next heating operation is performed next time based on the previous heating operation time A by any one of steps ST107 to ST110. The outdoor fan speed in heating operation is determined.

  First, in step ST107, the control unit 20 determines whether or not A <60 minutes, that is, whether or not the defrosting operation is started without passing 60 minutes from the start of the heating operation, and the determination result is Yes. In some cases, it is presumed that the defrosting operation is likely to be frequently performed. Therefore, in step ST107a, the outdoor fan rotation speed B is set to B = so that it is difficult to enter the defrosting operation in the next heating operation. Set to 1000 rpm, B + 3 steps.

  If the determination result in step ST107 is No (A ≧ 60 minutes), it is determined in the next step ST108 whether A <120 minutes. If the determination result is Yes, the next time in step ST108a. The outdoor fan rotation speed B in the heating operation is set to 900 rpm of B = B + 2 steps.

  If the determination result in step ST108 is No (A ≧ 120 minutes), it is determined in the next step ST109 whether A <180 minutes. If the determination result is Yes, the next time in step ST109a. The outdoor fan rotation speed B in the heating operation is set to 800 rpm of B = B + 1 step.

  If the determination result in step ST109 is No (A ≧ 180 minutes), it is determined in the next step ST110 whether A <240 minutes. If the determination result is Yes, the outdoor fan rotation speed B is determined. Without changing, the initial heating speed is kept at 700 rpm and the next heating operation is started.

  When the determination result in step ST110 is No (A ≧ 240 minutes), in step ST110a, the outdoor fan rotation speed B in the next heating operation is set to 600 rpm of B = B−1 step. In addition, when lowering the outdoor fan rotation speed B in this way, the minimum rotation speed (lower limit value) is the limit.

  Thus, according to the present invention, according to the previous heating operation time A (time from the start of the heating operation to the start of the defrosting operation), the outdoor fan rotation speed at the next heating operation after the completion of the defrosting operation is set. That is, as in the above embodiment, if A <60 minutes, 1000 rpm, 60 minutes ≦ A <120 minutes, 900 rpm, 120 minutes ≦ A <180 minutes, 800 rpm, 180 minutes. In the case of ≦ A <240 minutes, the initial 700 rpm is maintained, and in the case of A ≧ 240 minutes, the pressure is lowered to 600 rpm. As compared with the case where the rotational speed of the outdoor fan is uniformly set to the maximum rotational speed, useless power consumption of the outdoor fan can be reduced, and the frequency of entering the defrosting operation can be suppressed.

DESCRIPTION OF SYMBOLS 11 Compressor 12 Four-way valve 13 Outdoor heat exchanger 131 Outdoor fan 132 Outdoor air temperature sensor 133 Outdoor heat exchange temperature sensor 14 Expansion valve 16 Indoor heat exchanger 162 Room temperature sensor 17 Accumulator 20 Control part 210 Timer

Claims (2)

A refrigerating cycle in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected via a refrigerant pipe, and the four-way valve reversibly converts the refrigeration cycle into a heating operation and a cooling operation. A switching control unit,
During the heating operation, the control unit switches the four-way valve from the heating operation side to the cooling operation side under a predetermined defrosting operation start condition, and starts a defrosting operation for removing frost attached to the outdoor heat exchanger. After the start of the defrosting operation, air that performs control to resume the heating operation by ending the defrosting operation under a predetermined defrosting operation release condition and switching the four-way valve from the cooling operation side to the heating operation side. In the harmony machine,
The control unit stores the heating operation time A executed in the previous heating operation immediately before entering the defrosting operation when the defrosting operation is ended and the heating operation is restarted, and the outdoor heat exchanger is provided. An air conditioner characterized in that the rotation speed B of an outdoor fan is set according to the length of the heating operation time A and the heating operation is resumed.   The control unit has a reference time Th for determining whether the heating operation time A exceeds a predetermined time, and when the heating operation time A is shorter than the reference time Th, When the rotational speed B of the outdoor fan is made larger than the rotational speed Bf at the time of the previous heating operation and the heating operation time A is longer than the reference time Th, the rotational speed B of the outdoor fan is set to 2. The air conditioner according to claim 1, wherein the rotation speed is the same as or lower than the rotation speed Bf at the time of the previous heating operation.

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