JP4694457B2 - Air conditioner - Google Patents

Description

The present invention relates to an air conditioner capable of performing a defrosting operation for defrosting frost adhering to an outdoor heat exchanger while heating is continued during a heating operation by a heat pump operation.

  Conventionally, this type of heat pump type air conditioner defrosting method generally employs a defrosting method in which the four-way valve is switched and the refrigerant of the refrigeration cycle is flowed in the reverse direction. That is, in the defrosting operation, the flow direction of the refrigerant is the same as that during cooling, and a high-temperature and high-pressure refrigerant is passed through the outdoor heat exchanger to melt frost adhering to the heat exchanger.

  In this defrosting method, since the indoor heat exchanger becomes an evaporator during defrosting, there is a basic problem that the temperature of the room in the room is lowered and a feeling of cold air is felt. As a countermeasure against this basic problem, an invention of performing a defrosting operation while continuing heating has been considered (for example, see Patent Document 1).

  FIG. 5 is a configuration diagram of a refrigeration cycle of a conventional air conditioner.

  As shown in the figure, a compressor, a four-way valve, an indoor heat exchanger, a decompressor, a heat pump refrigeration cycle in which an outdoor heat exchanger is connected by a refrigerant circuit, and an indoor unit and an outdoor unit are each equipped with a blower. A first bypass circuit that connects the indoor heat exchanger and the pressure reducer connected to the refrigeration cycle, the four-way valve, and the outdoor heat exchanger is provided, and the two-way valve is provided in the first bypass circuit. And a refrigerant heater, and the compression connected between the four-way valve and the indoor heat exchanger connected to the refrigeration cycle, between the decompressor and the outdoor heat exchanger, or connected to the refrigeration cycle A second bypass circuit that connects between the compressor and the four-way valve and between the pressure reducer and the outdoor heat exchanger, a two-way valve is provided in the second bypass circuit, and the outdoor heat exchanger When performing defrosting, it passes through the refrigerant heater. And after opening the two-way valve of the first bypass circuit and opening the two-way valve of the second bypass circuit and the refrigerant heated by the refrigerant heater passes through the compressor, The flow through the indoor heat exchanger and the flow from the defrosting circuit to the flow through the outdoor heat exchanger are branched, and the branched refrigerant flows merge at the inlet of the refrigerant heating circuit, and the refrigerant heating is performed again. An invention configured to be heated by a vessel is disclosed.

  7 is a time chart during the defrosting operation of the conventional air conditioning apparatus.

  When the defrosting start determination is operated, the heating operation by the heat pump is shifted to the heating operation by the refrigerant heating operation in sequence 1 of the defrosting preparation section, the frequency of the compressor is set to a predetermined instruction frequency, and the opening of the decompressor The refrigerant heater is operated by heating the refrigerant heater.

  After the elapse of a predetermined sequence t1, the process proceeds to sequence 2, and the setting of the opening of the pressure reducer and the refrigerant heating two-way valve of the first bypass circuit are controlled in the opening direction.

  After a predetermined sequence t2 has elapsed, the process proceeds to sequence 3 of the defrosting section, the refrigerant heater continues to be turned on, the frequency of the compressor is set to the defrosting frequency, and the defrosting of the second bypass circuit is performed. The two-way valve is controlled in the opening direction, the opening of the decompressor is set in the throttle direction from the closing of the valve or the start of defrosting, and the defrosting operation is performed until the end of the defrosting section time considering the comfort of the room. At this time, since the four-way valve continues heating, it is not switched during defrosting in the heating circuit. The outdoor blower stops during defrosting.

  After completion of the defrosting, the process proceeds to sequence 4, and the two-way defrosting valve of the second bypass circuit is controlled in the closing direction with the refrigerant heating two-way valve of the first bypass circuit opened. By operating the outdoor fan, the heat stored in the outdoor heat exchanger during defrosting is dissipated to melt frost and ice.

  After elapse of a predetermined sequence t4, the process proceeds to sequence 5, returns to normal heat pump heating operation, the refrigerant heater is turned off, and the refrigerant heating two-way valve of the first bypass circuit is also controlled in the closing direction. . The decompressor is set to a normal operation opening.

  After a predetermined sequence t5 seconds, the defrosting operation control ends.

  FIG. 6 is a flowchart about the refrigerant heater from sequence 3 in the defrosting operation control of the conventional air conditioner.

After shifting to the sequence 3 of the defrosting section, the refrigerant heater is turned on, and the defrosting operation is performed until the end of the defrosting section time (predetermined set time t3 seconds) considering the comfort of the room. After the defrosting section, the process proceeds to the defrosting end control section sequence 4. The refrigerant heater continues to be turned on.
JP 2006-242443 A

However, this refrigeration cycle control system has the following problems.
This refrigeration cycle is controlled by defrosting operation in which a high-temperature and high-pressure refrigerant flows through the outdoor heat exchanger at the defrosting frequency in the defrosting section to melt the frost adhering to the heat exchanger and the amount of frost formation is reduced. As the pressure decreased, the low pressure increased, and the amount of refrigerant discharged from the compressor increased, resulting in a problem that the oil level of the compressor decreased.

  The present invention has been made in view of such problems of the prior art, and improves the reliability of the compressor while at the same time performing a stable defrosting operation that does not cause a decrease in comfort or a problem of unmelted melt. It aims at providing the air conditioning apparatus which can be implemented while continuing heating operation.

In order to solve the above conventional problems, the present invention provides a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a decompressor, and an outdoor heat exchanger are connected by a refrigerant circuit, and an indoor unit and an outdoor unit. A first bypass circuit that includes a blower and connects between the indoor heat exchanger and the decompressor connected to the refrigeration cycle, and between the four-way valve and the outdoor heat exchanger; The bypass circuit is provided with a two-way valve and a refrigerant heater, and further between the four-way valve and the indoor heat exchanger connected to the refrigeration cycle, between the decompressor and the outdoor heat exchanger, or the refrigeration A second bypass circuit is provided between the compressor and the four-way valve connected to a cycle, and between the pressure reducer and the outdoor heat exchanger, and a two-way valve is provided in the second bypass circuit. , Defrosting the outdoor heat exchanger When, by energizing the refrigerant heater, open the respective two-way valve of the first bypass circuit and the second bypass circuit, the refrigerant heated by the refrigerant heater, after passing through the compressor An air conditioner that performs a defrosting operation by being branched into a flow passing through the indoor heat exchanger and a flow passing through the outdoor heat exchanger from the second bypass circuit , wherein the first bypass circuit is connected An outdoor pipe temperature detecting means is provided on the outdoor heat exchanger side between the four-way valve of the refrigeration cycle and the outdoor heat exchanger, and the refrigerant is heated when the outdoor pipe temperature detecting means exceeds a predetermined temperature during the defrosting section. This is characterized in that the pressure increase of the refrigerant that occurs as the amount of frost formation on the outdoor heat exchanger is reduced by turning off the heater is suppressed .

  The air conditioner of the present invention can perform a stable defrosting operation that does not cause a decrease in comfort and a problem of undissolved melt while improving the reliability of the compressor while continuing the heating operation.

The first invention includes a heat pump refrigeration cycle in which a compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger are connected by a refrigerant circuit, and an indoor unit and an outdoor unit each equipped with a blower. A first bypass circuit that connects between the indoor heat exchanger and the pressure reducer connected in a cycle, and between the four-way valve and the outdoor heat exchanger is provided, and the two-way valve and the first bypass circuit are provided in the first bypass circuit. The compressor provided with a refrigerant heater and further connected between the four-way valve connected to the refrigeration cycle and the indoor heat exchanger, between the decompressor and the outdoor heat exchanger, or connected to the refrigeration cycle And the four-way valve, and a second bypass circuit that connects the pressure reducer and the outdoor heat exchanger, a two-way valve is provided in the second bypass circuit, and the outdoor heat exchanger is removed. When frosting, the refrigerant heater is energized Opens the respective two-way valve of the first bypass circuit and the second bypass circuit, the refrigerant heated by the refrigerant heater, after passing through the compressor, the flow through the indoor heat exchanger And an air conditioner that performs a defrosting operation by branching from the second bypass circuit to the flow passing through the outdoor heat exchanger , wherein the four-way valve and the outdoor of the refrigeration cycle to which the first bypass circuit is connected An outdoor pipe temperature detecting means is provided on the outdoor heat exchanger side from between the heat exchanger and when the outdoor pipe temperature detecting means exceeds a predetermined temperature during the defrosting section, the refrigerant heater is turned off to turn the outdoor heat exchanger off In the defrosting section, high-temperature and high-pressure refrigerant is allowed to flow through the outdoor heat exchanger at the defrosting frequency to melt the frost adhering to the heat exchanger. In the defrosting operation When the tube temperature exceeds the specified temperature, the refrigerant heater is turned off, so that heat is exchanged in the outdoor heat exchanger without increasing the heat energy, so the low pressure can be lowered, and the refrigerant discharge rate from the compressor It is possible to suppress the reduction of the compressor oil level.

  Also, in the defrosting operation in which a high-temperature and high-pressure refrigerant flows through the outdoor heat exchanger at the defrosting frequency in the defrosting section to melt the frost adhering to the heat exchanger, the outdoor pipe temperature is maintained even when the refrigerant heater is turned off. When the temperature falls below a predetermined temperature, the refrigerant heater can be turned on again to increase the heat energy and increase the defrosting ability to melt the frost adhering to the heat exchanger. Since the remaining problems do not occur and the low pressure rises from the state where the low pressure is lowered, the compressor oil level can be prevented from being lowered.

  As described above, heating operation is continued with stable defrosting operation that suppresses low pressure rise and suppresses refrigerant discharge from the compressor, improves reliability, and does not cause deterioration of comfort or unmelted problems. Can be implemented.

  The second invention is characterized in that the heating output of the refrigerant heater is changed according to the outside air temperature during the defrosting operation. By performing this control, the outdoor heat exchanger is defrosted in the defrosting section. In the defrosting operation in which high-temperature and high-pressure refrigerant flows at the frequency to melt frost adhering to the heat exchanger, if the outside air temperature is low, the heating output of the refrigerant heater is increased to increase the defrosting capacity, and the outside air temperature is high. In this case, by reducing the heating output of the refrigerant heater and reducing the defrosting capacity, compressed oil can be obtained by defrosting operation with the optimal defrosting capacity and the optimal defrosting time by melting the outside air temperature and melting the refrigerant heater. Surface degradation can also be prevented.

  As described above, it is possible to carry out a stable defrosting operation while improving the reliability of the compressor by an optimal defrosting operation, and without causing a decrease in comfort and a problem of undissolved melt while continuing the heating operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a control block diagram showing Embodiment 1 according to the present invention.
As shown in the figure, the ON / OFF switching determination condition of the refrigerant heater from the sequence 3 of the defrosting section to the sequence 4 of the defrosting end control section is determined by the microcomputer 50 with the outdoor pipe temperature detecting means 51. The refrigerant heater ON / OFF determination unit 54 determines from the set time passage determination means 52, and when the condition is satisfied, the refrigerant heater is controlled to be ON or OFF.

  Next, FIG. 2 is a flowchart about the refrigerant heater from sequence 3 in the defrosting operation control showing the first embodiment according to the present invention.

  As shown in the figure, after the transition 101 to sequence 3 of the defrosting section 101, the refrigerant heater is turned ON 102. After the transition 101 to the sequence 3 of the defrosting section, if the elapsed time A seconds has passed the predetermined sequence set time t3 seconds by the set time elapsed determination 103, the process proceeds to the sequence 4 of the defrosting end control section 109.

  If the elapsed time A seconds has not passed the sequence set time t3 seconds, it is determined by the next outdoor pipe temperature determination 104 whether the current outdoor pipe temperature T ° C has exceeded a predetermined set outdoor pipe temperature ta ° C. If the outdoor pipe temperature ta ° C. is not exceeded, the refrigerant heater ON102 is continued.

  If the outdoor piping temperature ta ° C. is exceeded, the refrigerant heater is turned off 105.

  After the refrigerant heater is turned off 105, it is determined again by the set time elapse determination 106 whether the elapsed time A seconds has passed the predetermined sequence set time t3 seconds, and if it has elapsed, the routine proceeds to sequence 4 in the defrosting end control section 109. .

  If the elapsed time A seconds has not passed the sequence set time t3 seconds, it is determined by the next outdoor pipe temperature determination 107 whether the current outdoor pipe temperature T ° C. has fallen below a predetermined set outdoor pipe temperature tb ° C.

  If the outdoor piping temperature is less than tb ° C., the refrigerant heater is turned ON again.

  If it is not lower than the outdoor pipe temperature tb ° C., it is determined by the next outdoor pipe temperature determination 108 whether the current outdoor pipe temperature T ° C. exceeds a predetermined set outdoor pipe temperature tc ° C.

  If the outdoor piping temperature tc ° C is not exceeded, the refrigerant heater OFF 105 is continued.

  If the outdoor piping temperature tc ° C is exceeded, the defrosting section is terminated and the routine proceeds to sequence 4 of the defrosting termination control section.

  In sequence 4 after the refrigerant heater ON / OFF control, the refrigerant heater is turned off.

  Next, FIG. 3 is a time chart showing the behavior when the defrosting operation control according to the present invention is operated.

  As shown in the figure, when the defrost start determination is activated, the operation is shifted from the heating operation by the heat pump to the heating operation by the refrigerant heating operation in the sequence 1 in the defrost preparation section, and the frequency of the compressor 1 is set to a predetermined instruction frequency. The opening degree of the decompressor 4 is set, and the refrigerant heater 9 is heated to perform the refrigerant heating operation.

  At this time, the inner fan continues to heat and therefore does not stop.

After a predetermined sequence t1 seconds elapses, the sequence proceeds to sequence 2 where the opening degree of the decompressor 4 and the refrigerant heating two-way valve 7 of the first bypass circuit 6 are controlled in the opening direction. After a predetermined sequence t2 seconds elapses, the process proceeds to sequence 3 of the defrosting section, the frequency of the compressor 1 is set to the defrosting frequency, and the second
The defrosting section in which the comfort of the room is taken into consideration by controlling the two-way defrosting valve 14 of the bypass circuit 13 in the opening direction and setting the opening degree of the decompressor 4 in the throttle direction from closing the valve or starting the defrosting The defrosting operation is performed until the end of time t3 seconds.

  At this time, the refrigerant heater 9 continues to be ON, the outdoor pipe temperature detecting means 20 detects the outdoor pipe temperature, and the ON / OFF of the refrigerant heater is controlled by the outdoor pipe temperature determination. At this time, since the four-way valve 2 continues heating, the heating circuit remains in the heating circuit and is not switched during defrosting. The outdoor blower 17 stops during defrosting.

  After completion of defrosting, the process proceeds to sequence 4, the refrigerant heater is turned off, and the two-way defrosting of the second bypass circuit 13 is performed in the state in which the refrigerant heating two-way valve 7 of the first bypass circuit 6 is opened. By controlling the valve 14 in the closing direction and operating the outdoor blower 17, the heat stored during the defrosting is radiated to the outdoor heat exchanger 5 to melt frost and ice.

  After a lapse of a predetermined sequence t4 seconds, the process proceeds to sequence 5, the normal heat pump heating operation is restored, the refrigerant heater 9 continues to be turned off, and the refrigerant heating two-way valve 7 of the first bypass circuit 6 is also closed. Be controlled. The decompressor 4 is set to the normal operation opening.

  After a predetermined sequence t5 seconds, the defrosting operation control ends.

(Embodiment 2)
FIG. 1 is a control block diagram showing a second embodiment according to the present invention.

  As shown in the figure, the heating output change determination condition of the refrigerant heater from the sequence 3 in the defrosting section to the sequence 4 in the defrosting end control section is set with the outdoor pipe temperature detecting means 51 in the microcomputer 50. The heating output change determination unit 54 of the refrigerant heater determines the passage of time determination means 52 and the outside air temperature detection means 53, and controls the heating output of the refrigerant heater according to the conditions.

  Next, FIG. 4 is a flowchart about the refrigerant heater from sequence 3 in the defrosting operation control showing the second embodiment according to the present invention.

  As shown in the figure, after transition 101 to sequence 3 of the defrosting section, it is determined by the outside air temperature determination 201 whether the current outside air temperature B ° C. is higher or lower than a predetermined set outside air temperature td ° C.

  When the current outside air temperature B ° C. is higher than a predetermined set outside air temperature td ° C., the heating output of the refrigerant heater 9 is Qe%, and when the current outside air temperature B ° C. is lower than the predetermined set outside air temperature b ° C., the refrigerant The heating output of the heater 9 is controlled to Qf%.

  At this time, the output of the refrigerant heater is Qe% <Qf%.

  In this case, the temperature is not limited to the predetermined set temperature td ° C., and may be set in several temperature ranges.

  After the transition 101 to the sequence 3 of the defrosting section, if the elapsed time A seconds has passed the predetermined sequence set time t3 seconds by the set time elapsed determination 103, the process proceeds to the sequence 4 of the defrosting end control section 109.

  If the elapsed time A seconds has not passed the sequence set time t3 seconds, it is determined by the next outdoor pipe temperature determination 104 whether the current outdoor pipe temperature T ° C has exceeded a predetermined set outdoor pipe temperature ta ° C.

  If it does not exceed the outdoor piping temperature ta ° C., the process proceeds to the outside air temperature determination 201 to control the heating output of the refrigerant heater. If the outdoor piping temperature ta ° C. is exceeded, the refrigerant heater is turned off 105.

  After the refrigerant heater is turned off 105, it is determined again by the set time elapse determination 106 whether the elapsed time A seconds has passed the predetermined sequence set time t3 seconds, and if it has elapsed, the routine proceeds to sequence 4 in the defrosting end control section 109. .

  If the elapsed time A seconds has not passed the sequence set time t3 seconds, it is determined by the next outdoor pipe temperature determination 107 whether the current outdoor pipe temperature T ° C. has fallen below a predetermined set outdoor pipe temperature tb ° C.

  If it is below outdoor piping temperature tb degreeC, it will transfer to the outdoor temperature determination 201, and the heating output of a refrigerant | coolant heater will be controlled. If it is not lower than the outdoor pipe temperature tb ° C., it is determined by the next outdoor pipe temperature determination 108 whether the current outdoor pipe temperature T ° C. exceeds a predetermined set outdoor pipe temperature tc ° C.

  If the outdoor piping temperature tc ° C is not exceeded, the refrigerant heater OFF 105 is continued. If the outdoor piping temperature tc ° C is exceeded, the defrosting section is terminated and the routine proceeds to sequence 4 of the defrosting termination control section. In sequence 4 after the refrigerant heater ON / OFF control, the refrigerant heater is turned off.

  As described above, since the air conditioner of the present invention can perform a stable defrosting operation while improving the reliability of the compressor, this control method is also used in the defrosting operation of a heat pump air conditioner. Applicable.

Control block diagram according to the present invention The flowchart about the refrigerant | coolant heater from the sequence 3 in the defrost operation control which shows Embodiment 1 concerning this invention. Time chart of Embodiment 1 at the time of defrosting operation concerning this invention The flowchart about the refrigerant | coolant heater from the sequence 3 in the defrost operation control which shows Embodiment 2 concerning this invention. Configuration of conventional air conditioner The flowchart about the refrigerant | coolant heater from the sequence 3 in the defrost operation control which shows the form of a prior art example Time chart during conventional defrosting operation

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Pressure reducer 5 Outdoor heat exchanger 6 1st bypass circuit 7 Two-way valve for refrigerant heating 8 Refrigerant heating pressure reducer 9 Refrigerant heater 10 Heater heater 11 Refrigerant passage pipe Part 12 Heat storage part 13 Second bypass circuit 14 Two-way valve for defrosting 15 Defrosting decompressor 16 Indoor fan 17 Outdoor fan 18 Indoor unit 19 Outdoor unit 20 Outdoor pipe temperature detecting means 50 Microcomputer 51 Outdoor pipe temperature detecting means 52 Setting temperature progress determination means 53 Outside air temperature detection means 55 Refrigerant heater ON / OFF determination section or refrigerant heater output change determination section 101 Start of defrosting section sequence 3 102 Refrigerant heater ON
103 Set time elapsed determination 104 Outdoor piping temperature determination 105 Refrigerant heater OFF
106 Determination of passage of set time 107 Outdoor pipe temperature determination 108 Outdoor pipe temperature determination 109 Transition to defrosting end control section sequence 4 201 Outdoor air temperature determination 202 Heating output Qe% of refrigerant heater
203 Heating output Qf% of refrigerant heater

Claims (2)

A compressor, a four-way valve, an indoor heat exchanger, a decompressor, an outdoor heat exchanger connected by a refrigerant circuit, a heat pump refrigeration cycle, and an indoor unit and an outdoor unit each equipped with a blower, and connected to the refrigeration cycle Providing a first bypass circuit connecting between the indoor heat exchanger and the decompressor, and between the four-way valve and the outdoor heat exchanger, providing a two-way valve and a refrigerant heater in the first bypass circuit; Further, between the four-way valve connected to the refrigeration cycle and the indoor heat exchanger, between the pressure reducer and the outdoor heat exchanger, or between the compressor and the four-way valve connected to the refrigeration cycle. And providing a second bypass circuit that connects the decompressor and the outdoor heat exchanger, providing a two-way valve in the second bypass circuit, and defrosting the outdoor heat exchanger, Energizing the refrigerant heater, the first Bypass circuit and opens the respective two-way valve in the second bypass circuit, the refrigerant heated by the refrigerant heater, after passing through the compressor, the flow through the indoor heat exchanger and the second An air conditioner that performs a defrosting operation by branching from a bypass circuit to a flow that passes through the outdoor heat exchanger , wherein the four-way valve of the refrigeration cycle to which the first bypass circuit is connected and an outdoor heat exchanger An outdoor pipe temperature detecting means is provided on the outdoor heat exchanger side, and when the outdoor pipe temperature detecting means exceeds a predetermined temperature during the defrosting section, the refrigerant heater is turned off and the frost amount of the outdoor heat exchanger is reduced. An air conditioner that suppresses an increase in the pressure of the refrigerant that occurs as the amount decreases . The air conditioner according to claim 1, wherein the refrigerant heater changes a heating output according to an outside air temperature detected by an outdoor pipe temperature detecting means .

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