JP2011099644A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable refrigerating cycle device preventing outflow of refrigerating machine oil generated at a start of a high pressure shell type compressor. <P>SOLUTION: The refrigerating cycle device includes the compressor 1, an oil separator 6, an oil return circuit 8, an oil separator preheating means 9, an outside air temperature detection means 10 and a control means 11. By preheating the oil separator 6 in accordance with outside air temperature during stop of the compressor 1, retention of a liquid refrigerant in the oil separator 6 can be prevented. Thus, even if the liquid refrigerant is made to transiently flow out from the compressor 1 at a start initial stage, a liquid component can be separated and collected by the oil separator 6 to prevent outflow to a radiator, so as to avoid a refrigerating machine oil shortage state of the compressor 1. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a refrigeration cycle apparatus equipped with a high-pressure shell type compressor, and more particularly to a refrigeration cycle apparatus that needs to prevent the refrigeration oil from flowing out of the compressor at the initial startup stage.

  Conventionally, in this type of air conditioner, the compressor is preheated in order to prevent the temperature of the compressor from decreasing during stoppage and the refrigerant from being melted and accumulated in the refrigeration oil inside the compressor (for example, , See Patent Document 1).

  FIG. 5 is a flowchart showing the preheat treatment of the compressor that is performed while the operation of the conventional refrigeration cycle apparatus described in Patent Document 1 is stopped. As shown in FIG. 5, a preheat amount control unit that detects the outside air temperature at a predetermined time interval and sets a preheat amount according to the outside air temperature is provided to perform preheat treatment of the compressor.

JP-A-8-114346

  However, in the high-pressure shell type compressor, even if the liquid refrigerant is prevented from staying inside the stopped compressor shell, the structure of the compressor against the pressure increase inside the compressor shell at the initial startup stage As the temperature rises, the refrigerant condenses inside the compressor shell, liquid refrigerant is generated, the liquid level inside the compressor shell rises, and a large amount of refrigeration oil flows out of the compressor together with a large amount of liquid refrigerant. End up. Further, in the conventional configuration, only the preheating means of the compressor is provided, and even if the liquid refrigerant stays in the compressor during the stop, the liquid refrigerant cannot stay in the oil separator. It was.

  In the state in which the retention of liquid refrigerant in the oil separator has not been prevented, as described above, if a large amount of refrigeration oil flows out from the compressor together with a large amount of liquid refrigerant and flows into the oil separator in the initial startup stage, The liquid level rises, and a large amount of refrigerating machine oil flows out to the radiator together with the liquid refrigerant without being recovered by the oil separator. Since the refrigeration oil that has flowed out of the radiator circulates in the system and returns to the compressor, it takes a long time to return to the compressor, and during that time, there is a shortage of refrigeration oil inside the compressor. Had.

  The present invention solves the above-described conventional problems, and prevents the oil from flowing out from the oil separator against the outflow of the refrigerating machine oil from the compressor that increases transiently at the start-up, and the lack of refrigerating machine oil inside the compressor. An object is to provide a highly reliable refrigeration cycle apparatus that can always be avoided.

In order to solve the conventional problems, a refrigeration cycle apparatus according to the present invention includes a refrigerant circuit formed by connecting a compressor, a radiator, a throttle mechanism, and an evaporator, and an oil disposed in a discharge pipe of the compressor. A separator, an oil return circuit for returning the refrigeration oil separated by the oil separator to the suction pipe of the compressor, preheating means for preheating the oil separator, outside air temperature detecting means for detecting outside air temperature, and control means; And the operation of the preheating means is controlled based on the outside air temperature detected by the outside air temperature detecting means to prevent the liquid refrigerant from staying in the oil separator during the stop and start up Even if the amount of refrigeration oil flowing out of the compressor increases transiently, the oil separator can be separated by separating the liquid components with an oil separator and ensuring a sufficient volume to stay. The refrigerating machine oil can return to the compressor suction pipe by chromatography data, and it can prevent the outflow of refrigeration oil from the oil separator.

  According to the present invention, the refrigeration oil flowing out from the compressor that increases transiently at the start-up can be prevented from flowing out from the oil separator, and a reliable refrigeration that can always avoid shortage of refrigeration oil inside the compressor. A cycle device can be provided.

Cycle configuration diagram of refrigeration cycle apparatus in Embodiment 1 of the present invention Flow chart of preheating operation of oil separator of control means of same refrigeration cycle apparatus Cycle configuration diagram of refrigeration cycle apparatus in Embodiment 2 of the present invention Flow chart of preheating operation of oil separator of control means of same refrigeration cycle apparatus Flow chart of preheating operation of conventional refrigeration cycle apparatus

  According to a first aspect of the present invention, there is provided a refrigerant circuit formed by connecting a compressor, a radiator, a throttle mechanism, and an evaporator, an oil separator disposed in a discharge pipe of the compressor, and refrigerating machine oil separated by the oil separator. And an oil return circuit for returning to the suction pipe of the compressor, a preheating means for preheating the oil separator, an outside air temperature detecting means for detecting the outside air temperature, and a control means, which are detected by the outside air temperature detecting means. The refrigeration cycle apparatus controls the operation of the preheating means based on an outside air temperature.

  The second invention is characterized in that the oil separator is preheated when the outside air temperature detected by the outside air temperature detecting means is equal to or lower than a predetermined temperature.

  According to a third aspect of the present invention, there is provided a refrigerant circuit formed by connecting a compressor, a radiator, a throttle mechanism, and an evaporator, an oil separator disposed in a discharge pipe of the compressor, and refrigerating machine oil separated by the oil separator. , An oil return circuit for returning to the suction pipe of the compressor, preheating means for preheating the oil separator, discharge pressure detecting means for detecting the discharge pressure of the compressor, and temperature detection for detecting the outer temperature of the oil separator Means for controlling the operation of the preheating means based on the discharge pressure detected by the discharge pressure detection means and the temperature detected by the oil separator temperature detection means. It is a feature.

  According to a fourth aspect of the present invention, the preheating amount of the preheating unit is set so that the temperature difference between the saturation temperature corresponding to the discharge pressure detected by the discharge pressure detection unit and the temperature detected by the oil separator temperature detection unit is within a predetermined range. It is characterized by adjusting.

  According to this, by having the preheating means for preheating the oil separator, it is possible to prevent the liquid refrigerant from staying in the stopped oil separator, and a large amount of refrigeration oil flows out of the compressor together with the liquid refrigerant during startup. However, by temporarily retaining the liquid component in the oil separator, separating the liquid component and returning it to the suction pipe of the compressor, it is possible to prevent the refrigerating machine oil from flowing out to the radiator and reliably return it to the compressor. .

In addition, by preventing the liquid refrigerant from staying in the oil separator that is stopped, the return of the liquid refrigerant from the oil return circuit at the time of start-up can be reduced as compared with the case of not preheating, and the intake gas of the compressor can be reduced. By keeping the dryness high, it is possible to promote overheating of the compressor and to suppress the condensation of the refrigerant inside the compressor shell, so that the amount of refrigeration oil flowing out of the compressor together with the liquid refrigerant can be reduced.

  Moreover, it is possible to prevent a shortage of refrigeration oil in the compressor by preventing a large amount of refrigeration oil flowing out together with the liquid refrigerant from the compressor at the start-up from flowing into the radiator.

  Further, the liquid refrigerant can be prevented from staying in the oil separator, and the amount of power consumed by the preheating means can be reduced.

  In addition, liquid components can be reliably separated into gas and liquid with an oil separator against the transient increase in refrigeration oil flow from the compressor during startup, and the refrigeration oil can be collected in the suction pipe. By preventing the liquid refrigerant from staying in the oil separator, the return amount of the liquid refrigerant from the oil return circuit at the time of start-up can be reduced as compared with the case where there is no preheating.

  Also, the amount of refrigerant oil flowing out of the compressor together with the liquid refrigerant can be increased by keeping the dryness of the intake gas of the compressor high, thereby promoting the overheating of the compressor and suppressing the condensation of the refrigerant inside the compressor shell. Accordingly, it is possible to always prevent the occurrence of a shortage of refrigeration oil in the compressor and provide a highly reliable refrigeration cycle apparatus.

  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 cycle configuration diagram of the refrigeration cycle apparatus in the first embodiment of the present invention, and FIG. 2 is a preheating operation of the oil separator of the control means of the refrigeration cycle apparatus in the first embodiment of the present invention. A flowchart is shown.

  In FIG. 1, the compressor 1 is a high-pressure shell type compressor, and connects the indoor heat exchangers 2a and 2b as radiators, the outdoor expansion valve 22 as a throttle mechanism, and the outdoor heat exchanger 4 as an evaporator to connect a refrigerant circuit. Forming. An oil separator 6 is disposed in the discharge pipe 5 of the compressor 1, and an oil return circuit 8 that returns the refrigeration oil separated by the oil separator 6 to the suction pipe 7 of the compressor 1, and preheats the oil separator 6. The oil separator preheating means 9 for detecting the outside air temperature, the outside air temperature detecting means 10 for detecting the outside air temperature, and the oil separator preheating means 10 when the temperature is not more than a predetermined outside air temperature based on the outside temperature detected by the outside air temperature detecting means 10 And control means 11 to be used.

  In the refrigeration cycle apparatus configured as described above, the control means 11 performs a preheating operation of the oil separator shown in the flowchart of FIG. Hereinafter, description will be given with reference to the flowchart of FIG. Note that the preheating operation of the oil separator while the compressor is stopped is performed every predetermined time.

First, the outside air temperature detecting means 10 detects the outside air temperature. Next, it is determined whether the detected outside air temperature Tair is lower than a predetermined temperature T. When the outdoor temperature Tair is equal to or higher than the predetermined temperature T, the oil separator preheating means is turned off to finish the processing, and the processing from the outdoor temperature detection is performed again after a predetermined time has elapsed. When the outdoor temperature Tair is lower than the predetermined temperature T, the oil separator preheating means 9 is ON / OFF controlled in accordance with the ON / OFF time ratio set in advance according to the outdoor temperature, and the processing is performed when the predetermined time elapses. The process from the outside temperature detection is performed again. The ON / OFF time ratio is such that the lower the outside air temperature,
It is set so that the ratio of ON time increases and the amount of preheating increases.

  By controlling the oil separator preheating means 9 and preheating the oil separator 6 in this way, it is possible to prevent liquid refrigerant from staying in the oil separator 6 while the compressor 1 is stopped.

  Incidentally, the high-pressure shell type compressor 1 is usually equipped with a crankcase heater 14 and used by the control means 11 in the same manner as the oil separator preheating means 9 in order to prevent liquid refrigerant from staying in the compressor 1. The compressor 1 is preheated to prevent the liquid refrigerant from staying in the compressor shell.

  However, even if the liquid refrigerant is prevented from staying by preheating during the stop, the temperature rise of the structure is delayed at the initial startup stage of the compressor 1 with respect to the pressure rise in the shell of the compressor 1. The refrigerant condenses inside the machine shell, the liquid refrigerant accumulates inside the compressor shell, the liquid level rises, and a large amount of liquid refrigerant and refrigerating machine oil flow out of the compressor 1 in a transient manner.

  As described above, even if a large amount of liquid refrigerant and refrigeration oil flow out of the compressor 1 at the start-up, if the oil separator preheating means 9 can prevent the liquid refrigerant from staying in the oil separator 6, the liquid component Can be separated by the oil separator 6 and once retained in the oil separator 6. Since the liquid component separated by the oil separator 6 is returned to the suction pipe 7 of the compressor 1 through the oil return circuit 8, it is possible to prevent the refrigerating machine oil from flowing out to the indoor heat exchangers 2a and 2b serving as radiators. .

  Further, by preventing the liquid refrigerant from staying in the oil separator 6 that is stopped, the amount of liquid refrigerant that returns from the oil return circuit 8 to the suction pipe 7 after activation can be reduced, and the intake gas of the compressor 1 can be reduced. By increasing the degree of dryness, the compressor 1 can be easily overheated, the time during which the condensing action occurs inside the compressor shell is shortened, and the outflow amounts of the liquid refrigerant and the refrigerating machine oil can be reduced.

  As described above, in the present embodiment, the oil separator preheating means 9 for preheating the oil separator 6 and the control means 11 using the oil separator preheating means 9 according to the outside air temperature are provided, and the oil separator being stopped is provided. By preventing the liquid refrigerant from staying in the refrigerant 6, the refrigerant oil is prevented from flowing out to the radiator, and the compressor 1 can be prevented from running out of the refrigerant oil.

  In the present embodiment, by switching the four-way valve 15, the outdoor heat exchanger 4 can be used as a radiator, and the indoor heat exchangers 2a and 2b can be used as an evaporator. Even so, it is possible to prevent the refrigerating machine oil from flowing out to the radiator, and it is possible to prevent the compressor 1 from running out of the refrigerating machine oil.

(Embodiment 2)
FIG. 3 is a cycle configuration diagram of the refrigeration cycle apparatus according to the second embodiment of the present invention, and FIG. 4 is a preheating operation of the oil separator of the control means of the refrigeration cycle apparatus according to the second embodiment of the present invention. A flowchart is shown.

  In FIG. 3, the oil separator temperature detecting means 13 detects the outer temperature of the oil separator 6. Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

With respect to the refrigeration cycle apparatus configured as described above, the control means 11 performs the preheating operation of the oil separator shown in the flowchart of FIG. Hereinafter, description will be given with reference to the flowchart of FIG. Note that the preheating operation of the oil separator while the compressor is stopped is performed every predetermined time.

  First, a temperature difference ΔT between the saturation temperature corresponding to the discharge pressure detected by the discharge pressure detection means 12 and the temperature detected by the oil separator temperature detection means 13 is calculated. Next, it is determined whether the calculated temperature difference ΔT is less than a predetermined temperature difference SH.

  If the temperature difference ΔT is equal to or greater than the predetermined temperature difference SH, the oil separator preheating means 9 is turned off to finish the process, and after a predetermined time has elapsed, the process returns to the temperature difference ΔT calculation stage and performs the process again. When the temperature difference ΔT becomes less than the predetermined temperature T, the oil separator preheating means is turned on to finish the process, and after a predetermined time has passed, the process returns to the temperature difference ΔT calculation step and the process is performed again.

  Thus, by controlling the oil separator preheating means 9 and preheating so that the oil separator 6 is overheated, the liquid refrigerant is reliably prevented from staying in the oil separator 6 while the compressor 1 is stopped. At the same time, the amount of power consumed by the oil separator preheating means 9 can be reduced.

  As described above, in the present embodiment, the oil separator preheating means 9 for preheating the oil separator 6, the oil separator temperature detecting means 13 for detecting the outer temperature of the oil separator 6, and the discharge pressure of the compressor 1 are detected. The discharge pressure detecting means 12 to be operated, and the temperature difference ΔT between the saturation temperature corresponding to the discharge pressure detected by the discharge pressure detecting means 12 and the outer temperature of the oil separator 6 detected by the oil separator temperature detecting means 13. The control means 11 using the oil separator preheating means 9 is provided, so that liquid refrigerant can be prevented from staying in the stopped oil separator 6 and the amount of power consumed by the oil separator preheating means 13 can be reduced.

  As described above, the refrigeration cycle apparatus according to the present invention reliably separates and collects liquid components with an oil separator against the outflow of refrigeration oil from the compressor that increases transiently at startup, and the compressor refrigeration oil is insufficient. Therefore, it can be applied to uses such as a refrigeration apparatus and a heat source apparatus using a high-pressure shell type compressor.

DESCRIPTION OF SYMBOLS 1 Compressor 2a, 2b Indoor heat exchanger 3a, 3b Indoor expansion valve 4 Outdoor heat exchanger 5 Discharge pipe 6 Oil separator 7 Intake pipe 8 Oil return circuit 9 Oil separator preheating means 10 Outside air temperature detection means 11 Control means 12 Discharge pressure Detection means 13 Oil separator temperature detection means 14 Crankcase heater 15 Four-way valve 16 Accumulator 17 Outdoor blower 18 Check valve 19a, 19b Indoor blower 20 Electromagnetic valve 21 Pressure reducing mechanism 22 Outdoor expansion valve

Claims (4)

A refrigerant circuit formed by connecting a compressor, a radiator, a throttle mechanism, and an evaporator, an oil separator disposed in a discharge pipe of the compressor, and refrigerating machine oil separated by the oil separator are sucked into the compressor. An oil return circuit for returning to the pipe, a preheating means for preheating the oil separator, an outside air temperature detecting means for detecting the outside air temperature, and a control means, based on the outside air temperature detected by the outside air temperature detecting means, A refrigeration cycle apparatus for controlling the operation of the preheating means. The refrigeration cycle apparatus according to claim 1, wherein the oil separator is preheated when the outside air temperature detected by the outside air temperature detecting means is equal to or lower than a predetermined temperature. A refrigerant circuit formed by connecting a compressor, a radiator, a throttle mechanism, and an evaporator, an oil separator disposed in a discharge pipe of the compressor, and refrigerating machine oil separated by the oil separator are sucked into the compressor. An oil return circuit for returning to the pipe, preheating means for preheating the oil separator, discharge pressure detecting means for detecting the discharge pressure of the compressor, temperature detecting means for detecting the outer temperature of the oil separator, and control means; And a refrigeration cycle apparatus that controls the operation of the preheating means based on the discharge pressure detected by the discharge pressure detection means and the temperature detected by the oil separator temperature detection means. The preheating amount of the preheating means is adjusted so that the temperature difference between the saturation temperature corresponding to the discharge pressure detected by the discharge pressure detection means and the temperature detected by the oil separator temperature detection means is within a predetermined range. The refrigeration cycle apparatus according to claim 3.