JP2013164236A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle device capable of improving reliability without increasing costs.SOLUTION: A refrigeration cycle device 1 includes an outdoor fan 61 distributing air to an outdoor heat exchanger 3, an indoor fan 71 distributing air to an indoor heat exchanger 5, an outdoor fan motor 62 driving the outdoor fan 61, an indoor fan motor 72 driving the indoor fan 71, an outdoor fan driving section 8 driving the outdoor fan motor 62, an indoor fan driving section 9 driving the indoor fan motor 72, and a control section 10 controlling a four-way valve 2, an expanding mechanism 4, the outdoor fan driving section 8 and the indoor fan driving section 9. The control section 10 outputs a command to drive the outdoor fan 61 to the outdoor fan driving section 68 in detecting a time change of an output value of a temperature sensor 100 over a prescribed value in a state of stopping the outdoor fan 61.

Description

  The present invention relates to a refrigeration cycle apparatus.

  In the heat pump refrigeration cycle apparatus, frost may form on the heat exchanger of the outdoor unit depending on outdoor temperature and humidity conditions. There is a control system (defrost operation) in which the refrigeration cycle is operated as a reverse cycle as a method for recovering the heating performance deterioration due to frost formation. The defrost operation does not require additional parts such as a heater and can easily remove frost, and various proposals have been made for methods of effectively performing this operation.

  For example, the technology described in Patent Document 1 below improves the defrost effect by controlling the fan motor rotation speed so as to offset the outside wind during the defrost operation.

JP 2010-169292 A

  However, in the conventional technique represented by the above-mentioned Patent Document 1, since the outdoor heat exchanger or the indoor heat exchanger that functions as an evaporator generates heat during defrost operation, the inside of the heat exchanger in a state where the attached frost has been melted is high.・ High humidity atmosphere. At this time, since the temperature around the heat exchanger is lower than that of the atmosphere, the humidity in the atmosphere is cooled to cause condensation, which may accelerate corrosion and the like. In particular, in an outdoor unit or a fan motor mounted on an indoor unit, copper wires, boards, and the like are arranged inside, and there is a possibility that the function of the refrigeration cycle apparatus itself may be lost if a conduction failure due to corrosion occurs.

  The dew condensation of the outdoor fan motor is due to the temperature difference from the atmosphere, but this temperature difference is not limited to the defrost operation.For example, the atmosphere of the outdoor fan motor may be due to the presence of a boiler, etc. Condensation is also possible when the temperature suddenly rises.

  As a method for preventing moisture from entering the fan motor due to condensation due to the above factors, it can be considered to change to a waterproof structure, but there is a problem that the cost increases due to the increase in size of the fan motor.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the refrigerating-cycle apparatus which can aim at the improvement of reliability, without increasing cost.

  In order to solve the above-described problems and achieve the object, a refrigeration cycle apparatus according to the present invention includes a compressor, an expansion mechanism, a four-way valve, an indoor heat exchanger that functions as a condenser or an evaporator, A refrigerating cycle device in which an outdoor heat exchanger functioning as an evaporator or an evaporator is connected by a refrigerant pipe, an outdoor fan for blowing air to the outdoor heat exchanger, and an indoor fan for blowing air to the indoor heat exchanger An outdoor fan motor that drives the outdoor fan, an indoor fan motor that drives the indoor fan, an outdoor fan drive that drives the outdoor fan motor, and an indoor fan drive that drives the indoor fan motor; The four-way valve, the expansion mechanism, the outdoor fan drive unit, a control unit that controls the indoor fan drive unit, and a temperature that detects the temperature of the atmosphere in the vicinity of the outdoor heat exchanger. A controller, and when the outdoor fan is stopped, the control unit issues a command to drive the outdoor fan when detecting that the amount of time change in the output value of the temperature sensor exceeds a predetermined value. It outputs to the said outdoor fan drive part, It is characterized by the above-mentioned.

  According to the present invention, there is an effect that the reliability can be improved without increasing the cost.

FIG. 1 is a structural diagram of a refrigeration cycle apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the relationship between the heating operation time and the heating capacity. FIG. 3 is a diagram illustrating an operation mode at a low temperature. FIG. 4 is a diagram illustrating a temperature change in the outdoor unit during the defrost operation by the refrigeration cycle apparatus. FIG. 5 is a diagram showing a temperature change in the outdoor unit during the defrost operation by the refrigeration cycle apparatus according to the embodiment of the present invention. FIG. 6 is a circuit diagram of the outdoor fan drive unit. FIG. 7 is a flowchart showing the operation of the control unit. FIG. 8 is a time chart of the outdoor fan rotation speed. FIG. 9 is a structural diagram of the outdoor unit.

  Embodiments of a refrigeration cycle apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a structural diagram of a refrigeration cycle apparatus 1 according to an embodiment of the present invention. The refrigeration cycle apparatus 1 has an outdoor unit 6 and an indoor unit 7 as main components. The outdoor unit 6 includes a four-way valve 2, an outdoor heat exchanger 3 that functions as a condenser or an evaporator, an expansion mechanism 4, an outdoor fan drive unit 8, a control unit 10, a refrigerant pipe 11, a compressor 13, an outdoor fan 61, temperature An outdoor fan motor 62 that drives the sensor 100 and the outdoor fan 61 is included. The indoor unit 7 includes an indoor heat exchanger 5 that functions as a condenser or an evaporator, an indoor fan drive unit 9, a refrigerant pipe 11, an indoor fan 71, and an indoor fan motor 72 that drives the indoor fan 71. ing.

  The outdoor fan 61 is a blower fan for blowing air to the outdoor heat exchanger 3 to promote heat exchange, and the indoor fan 71 is a blower fan for blowing air to the indoor heat exchanger 5 to promote heat exchange. is there. The outdoor fan motor 62 is a motor that rotates the outdoor fan 61, and the indoor fan motor 72 is a motor that rotates the indoor fan 71. The outdoor fan drive unit 8 is a circuit that supplies power to the outdoor fan motor 62, and the indoor fan drive unit 9 is a circuit that supplies power to the indoor fan motor 72. The control unit 10 is a control unit that controls the four-way valve 2, the compressor 13, the expansion mechanism 4, the outdoor fan drive unit 8, and the indoor fan drive unit 9 according to the temperature and humidity desired by the user. The refrigerant pipe 11 connects the compressor 13, the four-way valve 2, the indoor heat exchanger 5, the expansion mechanism 4, and the outdoor heat exchanger 3 so that the refrigerant can be circulated. The environmental conditions that cause condensation will be described in the description of the defrost operation during the heating operation. In the heating operation, the four-way valve 2 shown in FIG. 1 is in a state of connecting the discharge pipe (not shown) of the compressor 13 and the indoor heat exchanger 5. The temperature sensor 100 detects the temperature of the outdoor heat exchanger 3 or the ambient temperature.

  Next, the basic operation during the heating operation of the refrigeration cycle apparatus 1 in a low temperature environment will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram illustrating a relationship between the heating operation time and the heating capacity, and FIG. 3 is a diagram illustrating an operation mode at a low temperature. The horizontal axis represents time, and the vertical axis represents the heating capacity of the refrigeration cycle apparatus 1.

  When the surface temperature of the outdoor heat exchanger 3 is less than 0 degrees under low outdoor air conditions, moisture in the air adheres to the surface of the outdoor heat exchanger 3 as frost. Part A of FIG. 2 shows a point in time when frost formation on the surface of the outdoor heat exchanger 3 has started. When this frost grows until it blocks the air path of the outdoor heat exchanger 3, heat exchange between the outside air and the refrigerant is performed. Is not performed sufficiently, the heating capacity rapidly decreases as shown in part B of FIG. In the refrigeration cycle apparatus 1, a defrost operation is performed as shown in part C of FIG.

  The defrosting operation is realized by switching the four-way valve 2 in the reverse direction by the expansion mechanism 4. That is, the four-way valve 2 shown in FIG. 1 is performed by connecting a discharge pipe (not shown) of the compressor 13 and the outdoor heat exchanger 3 as indicated by a dotted line. Thereby, a high-temperature and high-pressure refrigerant is supplied to the outdoor heat exchanger 3 side, and frost adhering to the outdoor heat exchanger 3 can be melted by this heat. When the frost is removed, the defrosting operation is terminated as shown in part D of FIG. 3, the four-way valve 2 is switched again as shown in FIG. 1, and the heating operation is resumed.

  During the defrost operation, the outdoor heat exchanger 3 generates heat, and the adhering ice is melted to become water, and a part of it becomes water vapor. That is, since an increase in temperature and an increase in moisture occur at the same time, the atmosphere of the outdoor heat exchanger 3 becomes partially hot and humid compared to the surroundings.

  Next, the temperature change in the outdoor unit 6 during the defrost operation will be described with reference to FIG. FIG. 4 is a diagram showing a temperature change in the outdoor unit during the defrost operation by the refrigeration cycle apparatus 1. The horizontal axis represents time, and the vertical axis represents temperature. The solid line represents the temperature of the temperature sensor 100, the dotted line represents the motor temperature (the temperature of the outdoor fan motor 62), and the alternate long and short dash line represents the dew point temperature.

  The refrigeration cycle apparatus 1 actively drives the outdoor fan 61 to blow air to the outdoor heat exchanger 3 in the normal operation mode (rotation control mode) other than the defrost operation. Promotes heat exchange with the outside air. When the rotation control mode is the heating operation, the outdoor heat exchanger 3 may be frosted as described above. Therefore, the refrigeration cycle apparatus 1 is operated from the heating operation to the defrost operation as shown in part P of FIG. Switch to. When the defrost operation is started (t1), since the high-temperature refrigerant is supplied to the outdoor heat exchanger 3, the temperature of the outdoor heat exchanger 3 rises as shown in the Q part of FIG. As the frost melts, some of it becomes water vapor and the humidity increases. Note that the outdoor fan 61 is stopped after the defrost operation is started. Further, as the temperature and humidity of the outdoor heat exchanger 3 increase, the dew point temperature in the outdoor unit 6 increases as shown in the R part of FIG.

  The outdoor fan motor 62 is cooled to a low temperature by a heat exchanger that is in an evaporating operation immediately before the defrost operation, and has a larger heat capacity than air, so that the motor temperature is lower than the atmosphere even after the defrost operation starts. Kept. Therefore, as shown in S part of FIG. 4, when the dew point temperature of the atmosphere in the outdoor unit 6 becomes higher than the motor temperature, the outdoor fan motor 62 condenses water vapor and causes condensation. Since the amount of dew condensation depends on the dew point temperature and the motor temperature, as shown in FIG. 4, the area of the shaded portion corresponding to the difference between the dew point temperature and the motor temperature corresponds to the dew amount. Hereinafter, the shaded area is referred to as a motor dew generation area. The outdoor fan motor 62 is generally made of a metal such as a circuit board, iron, or copper, and therefore metal corrosion tends to proceed more easily as the condensation increases.

  Next, the temperature change at the time of the defrost driving | operation by the refrigerating-cycle apparatus 1 which concerns on embodiment of this invention using FIG. 5 is demonstrated. FIG. 5 is a diagram showing a temperature change in the outdoor unit 6 during the defrost operation by the refrigeration cycle apparatus 1 according to the embodiment of the present invention.

  When the defrost operation is started as shown in part P of FIG. 5, the ambient temperature in the vicinity of the outdoor heat exchanger 3 increases due to refrigerant condensation in the outdoor heat exchanger 3. The temperature sensor 100 measures the temperature of the atmosphere near the outdoor heat exchanger 3 and detects the temperature rise. When the time change rate of the temperature becomes equal to or greater than a predetermined value, the control unit 10 performs a blowing operation (condensation prevention operation) so that a high-temperature and high-humidity atmosphere does not drift near the motor. In this dew condensation prevention operation, for example, an AC voltage is applied to the windings of the outdoor fan motor 62 from the outdoor fan motor 8 so that the outdoor fan 61 gently flows air from the outdoor fan motor 72 side to the outdoor heat exchanger 3 side. It is realized by doing.

  By this dew condensation prevention operation, outside air is introduced into the vicinity of the outdoor fan motor 62 even after defrosting. For this reason, the temperature and humidity of the atmosphere in the vicinity of the motor do not change greatly before and after the defrost, and the dew condensation condition shown in FIG. 4 is not reached. That is, according to the dew condensation prevention operation of the refrigeration cycle apparatus 1 according to the embodiment, it is possible to reduce the dew amount of the outdoor fan motor 62 or to prevent dew condensation.

  It should be noted that the amount of air required to prevent the fan motor dew condensation is sufficient if the atmosphere in the vicinity of the outdoor heat exchanger 3 does not contact the outdoor fan motor 62. If the amount of air is large, the defrost of the outdoor heat exchanger 3 is sufficient. It is desirable that the outdoor fan motor 62 be operated at the minimum necessary number of rotations because this results in a decrease in effect and an increase in power consumption.

  Next, a specific method of the dew condensation preventing operation will be described with reference to FIGS. 6 is a circuit diagram of the outdoor fan drive unit 8, FIG. 7 is a flowchart showing the operation of the control unit 10, and FIG. 8 is a time chart of the outdoor fan rotation speed during heating of the control unit 10, FIG. 9 is a structural diagram of the outdoor unit 6.

  In FIG. 9, the general internal structure of the outdoor unit 6 will be described. The outdoor fan 61, the outdoor fan motor 62, and the outdoor heat exchanger 3 are arranged in this order when viewed from the front side (lower part of the figure). In normal operation (air-conditioning operation), the outdoor fan 61 is directed to the front side. Drive the outdoor fan.

  In FIG. 6, the outdoor fan drive unit 8 includes an outdoor fan control circuit 81 and an inverter 82 as main components. The inverter 82 applies a voltage to the outdoor fan motor 62, and the position sensor 63 built in the outdoor fan motor 62 detects the rotor position (magnetic pole position of the rotor) of the outdoor fan motor 62 or the rotation speed of the rotor. The outdoor fan control circuit 81 outputs a PWM signal to the inverter 82 based on information from the control unit 10 and the position sensor 63.

  The position sensor 63 of the outdoor fan motor 62 is composed of elements that output electrical signals, such as Hall ICs, photocouplers, photointerrupters, and their associated circuits, and is therefore fixed and built in the motor stator with a structure with a printed circuit board. Is done.

  Next, the operation of the control unit 10 will be described with reference to FIG. The temperature sensor 100 detects the temperature near the outdoor heat exchanger 3 and outputs the detection result to the control unit 10. The controller 10 periodically detects the temperature Tc in the vicinity of the outdoor heat exchanger 3 based on the output of the temperature sensor 100, for example (step S1). Further, the control unit 10 confirms the operating state of the outdoor fan motor 62. Specifically, the control unit 10 confirms whether or not the outdoor fan motor 62 is in normal operation (step S2). When the outdoor fan motor 62 is not in normal operation (ie, stopped) (No at Step S2), the control unit 10 calculates a time variation ΔTc / Δt of the temperature Tc, and this time variation ΔTc / It is determined whether Δt is equal to or greater than a predetermined value (S3). Here, Δt represents the amount of change over time, ΔTc represents the amount of temperature change at Δt, and the predetermined value is a positive predetermined value because it detects a temperature rise. When it is detected that the time variation ΔTc / Δt is equal to or greater than the predetermined value (step S3, Yes), the control unit 10 determines that there is a possibility of condensation, selects the condensation prevention operation mode, and selects the outdoor fan. A command corresponding to the operation mode is output to the control circuit 81 (step S5). Such a situation may occur, for example, during defrost operation. When it is detected that the time change amount ΔTc / Δt is less than the predetermined value (step S3, No), the process returns to step S1. When the outdoor fan motor 62 is in normal operation (air-conditioning operation) (step S2, Yes), the control unit 10 selects the normal operation mode and instructs the outdoor fan control circuit 81 to correspond to the normal operation mode. Is output (step S4).

  When the outdoor fan control circuit 81 receives a command corresponding to the dew condensation prevention operation mode, the outdoor fan control circuit 81 performs a dew condensation prevention operation (for example, a low speed reverse rotation operation). Specifically, the outdoor fan control circuit 81 determines the energization order to each phase of the outdoor fan motor 62 so as to rotate the outdoor fan 61 so that the wind flows from the outdoor fan 61 to the outdoor heat exchanger 3, for example. On the other hand, when the outdoor fan control circuit 81 receives a command corresponding to the normal operation mode, the outdoor fan control circuit 81 performs the normal operation mode (forward rotation operation). Specifically, the outdoor fan control circuit 81 determines an energization order to each phase of the outdoor fan motor 62 so as to rotate the outdoor fan 61 so that wind flows from the outdoor heat exchanger 3 to the outdoor fan 61.

  As described above, in the present embodiment, when the amount of time change of the output value of the temperature sensor 100 exceeds a predetermined value in a state where the outdoor fan 61 is stopped, the control unit 10 sends the outdoor fan drive unit 8 to the outdoor fan. Since a command for driving the fan 61 is output and the outdoor fan 61 is blown toward the inside of the outdoor unit 6, for example, the condensation of the outdoor fan motor 62 can be prevented, and the reliability can be increased without increasing the cost. Improvements can be made.

  Note that the air volume in the fan motor dew condensation prevention mode only needs to be enough to prevent air from coming into contact with the high-temperature, high-humidity heat exchanger near the low-temperature fan motor surface. Is sufficiently small compared to the airflow required for Further, if the air volume is excessive, the temperature of the outdoor heat exchanger 3 during the defrosting operation is lowered, which may hinder the defrosting of the outdoor heat exchanger 3 and cause a reduction in heating capacity. For this reason, the refrigeration cycle apparatus 1 with high reliability and high heating capacity can be obtained by setting the value of the frequency command in the fan motor dew condensation prevention mode to a value smaller than the lower limit value of the normal frequency command. FIG. 8 shows, for example, the fan rotation speed during heating operation and the fan rotation speed during defrost operation. The operation frequency (fan rotation speed) at the time of defrost operation is set to a value smaller than the minimum rotation speed at the time of air conditioning operation (only the heating operation is shown in the illustrated example).

  Further, when the outdoor fan motor 62 incorporates the rotor position sensor 63, an electric circuit is built in, and there is a possibility of pattern corrosion due to condensation. Therefore, the effect of the refrigeration cycle apparatus 1 according to the present embodiment. Will be big.

  In the refrigeration cycle apparatus 1, the temperature information of the outdoor temperature sensor 100 is generally notified only to the control unit 10 that performs refrigeration cycle control and is not given to the outdoor fan motor 62. Therefore, the start / stop determination in the fan motor dew condensation prevention mode is performed by the control unit 10, and there is an advantage that the refrigeration cycle apparatus 1 can be configured at low cost without an increase in sensors and signal lines.

  Further, in the present embodiment, it has been described that the dew condensation of the outdoor fan motor 62 during the defrost operation is suppressed. However, the dew condensation of the outdoor fan motor 62 is caused by a temperature difference from the atmosphere, and this temperature difference is caused by the defrost operation. For example, when a boiler or the like is installed in the vicinity, or when the ambient temperature suddenly rises due to solar radiation, there is a possibility of condensation. Therefore, this embodiment can be applied to cases other than during defrost operation.

  Further, the driving direction of the outdoor fan 61 during the defrost operation is preferably a direction in which air is introduced from the outdoor fan 61 into the outdoor unit, but it is also possible to select a direction opposite to this. However, since air moves inside the outdoor unit, it is effective in preventing condensation of the outdoor fan motor 62. That is, the outdoor fan motor 8 is set so that the voltage for driving the outdoor fan 61 is output to the outdoor fan motor 62 when the command corresponding to the dew condensation prevention operation mode is received. 62 is effective in preventing condensation. As described above, conventionally, the outdoor fan 61 is stopped during the defrost operation.

  Note that the refrigeration cycle apparatus 1 according to the embodiment of the present invention shows an example of the content of the present invention, and can be combined with another known technique, and departs from the gist of the present invention. Of course, it is possible to change and configure such as omitting a part within the range.

  As described above, the present invention is applicable to a refrigeration cycle apparatus, and is particularly useful as a refrigeration cycle apparatus that can improve reliability without increasing costs.

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle apparatus 2 Four-way valve 3 Outdoor heat exchanger 4 Expansion mechanism 5 Indoor heat exchanger 6 Outdoor unit 7 Indoor unit 8 Outdoor fan drive part 9 Indoor fan drive part 10 Control part 11 Refrigerant piping 13 Compressor 61 Outdoor fan 62 Outdoor Fan motor 63 Position sensor 71 Indoor fan 72 Indoor fan motor 81 Outdoor fan control circuit 82 Inverter

Claims (6)

A refrigeration cycle in which a compressor, an expansion mechanism, a four-way valve, an indoor heat exchanger that functions as a condenser or an evaporator, and an outdoor heat exchanger that functions as a condenser or an evaporator are connected by a refrigerant pipe. A device,
An outdoor fan that blows air to the outdoor heat exchanger;
An indoor fan for blowing air to the indoor heat exchanger;
An outdoor fan motor for driving the outdoor fan;
An indoor fan motor for driving the indoor fan;
An outdoor fan driving unit for driving the outdoor fan motor;
An indoor fan drive unit for driving the indoor fan motor;
A control unit for controlling the four-way valve, the expansion mechanism, the outdoor fan driving unit, and the indoor fan driving unit;
A temperature sensor for detecting the temperature of the atmosphere in the vicinity of the outdoor heat exchanger;
With
When the outdoor unit has stopped, the control unit detects a command to drive the outdoor fan to the outdoor fan driving unit when detecting that the amount of time change of the output value of the temperature sensor exceeds a predetermined value. A refrigeration cycle apparatus characterized by outputting.   The driving direction of the outdoor fan when the time change amount of the output value of the temperature sensor exceeds the predetermined value in a state where the outdoor fan is stopped is a direction in which air is introduced into the outdoor unit. The refrigeration cycle apparatus according to claim 1.   When the control unit detects that the time change amount of the output value of the temperature sensor exceeds the predetermined value during the defrost operation when the outdoor heat exchanger functions as an evaporator, the control unit controls the outdoor fan. The refrigeration cycle apparatus according to claim 1 or 2, wherein a command to drive is output to the outdoor fan drive unit.   The refrigeration cycle according to any one of claims 1 to 3, wherein an operating frequency of the outdoor fan motor for preventing dew condensation of the outdoor fan motor is smaller than a minimum rotational speed during air-conditioning operation. apparatus.   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the outdoor fan motor includes a position sensor for detecting a magnetic pole position or a rotation speed of the rotor.   The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the controller is configured to start and stop a predetermined command for suppressing condensation of the outdoor fan motor.

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