JP2005180753A - Air conditioner and refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner and a refrigerator that use existing piping to replace the heat-source equipment of a gas heat pump type system with that of an electric heat pump type system and that enable smooth start of a compressor by discharging liquid refrigerant in the compressor without producing an eddy current even if PAG oil with low volume resistivity is present in the compressor. <P>SOLUTION: In the air conditioner and the refrigerator, the existing piping of an air conditioner and a refrigerator that use PAG oil as refrigerator oil is reused to replace the heat-source equipment 1 of an electric heat pump type system that uses refrigerator oil other than PAG oil. The air conditioner and the refrigerator include a heating means for heating from the outside a compressor 10 built into the heat-source equipment 1, and a controller 32 that starts the compressor 10 after the compressor 10 has been heated by the heating means. The level of liquid that collects in the bottom of the compressor 10 prior to the start of the compressor 10 is kept lower than a conduit 28 inside the compressor 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to compressor operation control in an air-conditioning apparatus and a refrigeration apparatus in which an existing pipe is reused to replace a gas heat pump type system with a heat source unit of an electric heat pump type system.

  In the heat pump refrigeration system, after the operation of the compressor is stopped, the condensed liquid refrigerant moves to the compressor which is the coldest part in the heat pump refrigeration apparatus, and the liquid refrigerant dissolves in the refrigeration oil in the compressor and sleeps. The phenomenon tends to occur. Conventionally, if the compressor is restarted in this state, the liquid refrigerant dissolved in the refrigerating machine oil will be in the form of bubbles, causing a forming phenomenon that the refrigerating machine oil is taken out of the compressor, or the liquid refrigerant is compressed. Since the compressor sucks directly, liquid compression occurs and causes problems such as failure of the compressor. Therefore, energize the lead wire in the compressor with a small current that does not allow the compressor to operate. The oil reservoir space was heated, and after the liquid refrigerant dissolved in the refrigeration oil was quickly discharged to the outside, control was performed to start the compressor. (For example, refer to Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-292017 (page 7, FIG. 1)

However, in an air conditioner and a refrigeration system that replaces a gas heat pump system with a heat source machine of an electric heat pump system by reusing existing piping, a polyalkylene glycol (PAG) that is a refrigeration oil used in the gas heat pump system ) Oil may remain in the existing piping and may move due to the flow of refrigerant and accumulate in the compressor. Since this PAG oil has a smaller volume resistivity than the refrigeration oil used in the electric heat pump system, the liquid refrigerant stays in the compressor, and when the liquid refrigerant containing a lot of PAG oil comes into contact with the conductor in the compressor, The insulation resistance of the conducting wire is reduced, and an overcurrent is generated during energization.
The method of heating the inside of the compressor and discharging the liquid refrigerant to the outside includes the method of energizing the conducting wire part in the compressor to overheat the oil sump space in the sealed container as described above, and the inside of the compressor with a crankcase heater from the outside. There is a method of heating. In the method of energizing the conducting wire part in the compressor, when the liquid refrigerant staying in the compressor comes into contact with the conducting wire in the compressor and the concentration of the PAG oil becomes 0.5% or more, when energizing for the above reason, There is a problem that overcurrent is generated in the compressor and short-circuiting easily occurs, and the compressor cannot be started smoothly. In addition, even in a system in which the inside of the compressor is heated from the outside with a crankcase heater, the liquid refrigerant staying in the compressor is compressed without contacting a sufficient amount of liquid refrigerant from the compressor while being in contact with the conductor in the compressor. When the machine was started, an overcurrent was generated in the compressor, resulting in the same problem as described above.

  In addition, a gas heat pump type | system | group is an air conditioning apparatus and refrigeration apparatus which drive a compressor with a gas engine and performs cooling and heating with a heat pump system. The electric heat pump system is an air conditioner and a refrigeration apparatus that drive a compressor with an electric motor and perform cooling and heating with a heat pump system. Moreover, as a refrigerating machine oil of a gas heat pump system, PAG oil is generally used from the viewpoint of price and availability.

  The present invention has been made to solve the above problems, and is an air conditioner and a refrigeration apparatus in which a gas heat pump system is replaced with a heat source apparatus of an electric heat pump system, and the volume resistivity is reduced in the compressor. Even if low PAG oil is present, the liquid refrigerant in the compressor is discharged without generating an overcurrent, and an air conditioner and a refrigeration apparatus capable of smoothly starting the compressor are obtained.

  An air conditioner and a refrigerating apparatus according to the present invention are an air conditioner using PAG oil as a refrigerating machine oil and an existing heat pipe of a refrigerating apparatus that reuses existing piping of the refrigerating apparatus and uses a refrigerating machine oil other than PAG oil. An air conditioner and a refrigeration apparatus replaced by a heating means for heating a compressor built in the heat source machine from the outside, and a control for starting the compressor after heating the compressor by the heating means And the liquid level of the liquid collected at the bottom of the compressor before the compressor is started is lower than the conductor in the compressor.

  The present invention relates to an air conditioner and a refrigeration apparatus that reuses existing piping and replaces a gas heat pump type system with a heat source unit of an electric heat pump type system, and an external heating method even when PAG oil is accumulated in a compressor To heat the oil sump space in the airtight container of the compressor and start the compressor after the liquid refrigerant level is lower than the conductor in the compressor. It can start smoothly.

Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram showing an air conditioner according to Embodiment 1 of the present invention. A gas heat pump system using CFC or HCFC refrigerant is replaced with H407 refrigerant such as R407C or R410A that does not contain chlorine. It was replaced with the heat source machine of the electric heat pump system used.

  In FIG. 1, the refrigerant circuit of the electric heat pump type system includes a heat source unit 1, a first connection pipe 3, a second connection pipe 4 used in the gas heat pump type system, and the first connection pipe 3. It is mainly configured by the indoor unit 2 connected to the heat source unit 1 by the second connection pipe 4. The heat source unit 1 includes a heat source unit side heat exchanger 5, a first operation valve 6, a second operation valve 7, an accumulator 8, an oil separator 9 (oil separation means), a compressor 10, and a four-way valve 11. And have. The indoor unit 2 includes a flow rate regulator 12 and a use side heat exchanger 13.

  Next, a procedure for replacing the gas heat pump type system with a heat source machine of an electric heat pump type system will be described. First, CFC or HCFC refrigerant is recovered from the refrigerant circuit of the gas heat pump system, and then the CFC or HCFC refrigerant heat source unit and the indoor unit are removed from the first connection pipe 3 and the second connection pipe 4, The R407C or R410A refrigerant heat source unit 1 and the indoor unit 2 shown in FIG. 1 are connected to the first connection pipe 3 and the second connection pipe 4. In addition, it is necessary to fill the R407C or R410A refrigerant in advance to the heat source device 1 to be connected. Next, the first operation valve 6 and the second operation valve 7 are kept closed, and the indoor unit 2, the first connection pipe 3 and the second connection pipe 4 are evacuated, and then the first operation valve 6. And the second operation valve 7 are opened, and R407C or R410A refrigerant is additionally charged to perform normal air conditioning operation.

  Next, the configuration of the compressor 10 in the heat source device 1 will be described based on FIG. 2 which is a partial cross-sectional view of the compressor 10. In the compressor 10, a motor 22, a main shaft 23, and a compression element 24 are disposed in a sealed container 21 having a circular body part, and a refrigerant suction pipe 25 and a discharge pipe 26 are attached to the sealed container 21 so as to protrude. The charging unit 27 that conducts electricity is configured to be connected to the motor 22 by three conductive wires 28. FIG. 3 is an enlarged cross-sectional view of a charging unit in the compressor, and the charging unit 27 is a part for energizing the compressor 10. During the operation of the compressor 10, the gas refrigerant flows into the sealed container 21 from the suction pipe 25, is compressed by the compression element 24, is brought to a high temperature and a high pressure, passes through the discharge pipe 26, and is discharged from the compressor 10. Will be discharged.

  In addition, a crankcase heater 29 is installed around the sealed container 21 of the compressor 10, and the oil reservoir space 30 in the compressor 10 is heated by the crankcase heater 29, so that the refrigeration oil in the oil reservoir space 30 The liquid refrigerant dissolved in is evaporated and discharged from the compressor. Note that. The temperature of the crankcase heater temperature sensor 31 installed in the compressor 10 is controlled by the control device 32.

As shown in FIG. 4, the solubility curve of the refrigerant in the refrigeration oil shows a tendency that the solubility is lower as the temperature is higher. Further, the height of the liquid refrigerant level in the oil sump space 30 in the compressor 10 can be reduced as the refrigerant solubility is reduced. For this reason, by controlling the temperature in the compressor 10, the liquid level of the liquid refrigerant in the oil sump space 30 can be controlled.
In the present embodiment, the compressor 10 is heated from the outside by the crankcase heater 29 so that the liquid refrigerant has a level that does not come into contact with the conducting wire 28 connected to the charging unit 27, and the crankcase heater temperature is increased. The sensor 31 controls the temperature in the compressor 10 to be a preset target temperature of 40 ° C. (C in FIG. 4).
Here, the reason why the solubility of the refrigerant in the refrigerating machine oil is taken into account is that the refrigerant evaporates first because the boiling point of the refrigerant is lower than that of the refrigerating machine oil.

  As described above, the present embodiment is an air conditioner and a refrigeration apparatus in which a gas heat pump system is replaced with a heat source apparatus of an electric heat pump system, and PAG oil used as a refrigeration oil in the gas heat pump system is a compressor 10. Even if the liquid refrigerant is present, the crankcase heater 29 heats the compressor 10 to compress the refrigerant by evaporating the liquid refrigerant before starting the compressor 10 regardless of the liquid level of the liquid refrigerant. It can be discharged outside the machine 10. In addition, in order to start the compressor 10 with the liquid refrigerant level in which the PAG oil is melted lower than the conductor 28, an overcurrent is generated regardless of the concentration of the PAG oil in the compressor 10. Without the compressor 10 being able to start smoothly.

Next, the reason why the present invention is effective in the air-conditioning apparatus and the refrigeration apparatus using R410A as the refrigerant will be described.
For example, the liquid density of R407C refrigerant and R410A refrigerant at 20 ° C. is ρ _lR407C = 1159 [kg / m ³ ] and ρ _lR410A = 1085 [kg / m ³ ], respectively, so that the R410A refrigerant is more liquid than the R407C refrigerant. The density is small.
There is a risk that the R410A refrigerant having the same mass as the R407C refrigerant will be accidentally sealed in the field work. In this case, the R410A refrigerant has a larger capacity, so the liquid surface of the liquid refrigerant does not contact the conductor 28 with the R407C refrigerant. However, a situation occurs in which the R410A refrigerant contacts.

In addition, when the R410A refrigerant is used, the pressure is higher than that of the R407C refrigerant and the pipe needs to be made thinner. Therefore, if the same amount of the R410A refrigerant as the R407C refrigerant is sealed, the amount of refrigerant circulating in the pipe is reduced and compressed. The possibility that the amount of liquid refrigerant that accumulates in the oil sump space 30 in the machine 10 increases is increased.
If the R410A refrigerant having the same mass as the R407C refrigerant is mistakenly filled in the field work, the circuit designed for the R410A refrigerant will be overfilled, increasing the risk that the compressor 10 will be submerged with the refrigerant. As described above, the R410A refrigerant may have a larger capacity of refrigerant that accumulates in the compressor when the operation is stopped than the R407C refrigerant. Therefore, the present invention is more than the air conditioner and the refrigeration apparatus that use R407C as the refrigerant. This is particularly effective in an air conditioner and a refrigerating apparatus using R410A.

Embodiment 2. FIG.
FIG. 5 is a partial cross-sectional view showing the compressor in the second embodiment, in which the operation of the compressor 10 is controlled based on the internal temperature of the compressor. In FIG. 5, the same components as those in FIG. 2 and the corresponding components are denoted by the same reference numerals, and description thereof is omitted.
In FIG. 5, reference numeral 33 denotes an in-compressor temperature sensor arranged inside the compressor 10.
Next, the temperature control in FIG. 5 will be described based on the flowchart in FIG.
First, the compressor temperature T1 is read from the compressor temperature sensor 33 (step S1), and the pressure P in the compressor 10 is obtained from the compressor temperature T1 using the Mollier diagram (step S2). Next, the temperature T2 of the crankcase heater 29 is read from the crankcase heater temperature sensor 31 (step S3), and based on the relationship diagram shown in FIG. The solubility W of the refrigerant in the refrigerating machine oil is read from the intersection B between the value of the pressure P in the compressor 10 and the value of the temperature T2 of the crankcase heater on the horizontal axis (step S4). Next, it is determined whether or not the current solubility value W is larger than a predetermined solubility target value Wm (step S5). If larger, the crankcase heater 29 is turned on (step S6) and heated. If it is smaller, the power is turned off (step S7).
In the present embodiment, the compressor internal temperature sensor 33 is arranged inside the compressor 10, but instead of the compressor internal temperature sensor 33, a temperature sensor is arranged outside the compressor 10 to obtain the compressor internal temperature T1. May be used.
4, when the solubility W of the refrigerant in the refrigeration oil is obtained, the temperature T2 of the crankcase heater temperature sensor 31 is used in the present embodiment. Instead, the compressor temperature T1 of the compressor temperature sensor 33 is used. May be used.

  In the first embodiment, only the temperature control in the compressor 10 is considered so that the liquid refrigerant does not come into contact with the conductive wire 28, and the temperature in the compressor 10 is changed from point A to point C by the crankcase heater 29 at 40 ° C. In the second embodiment, the liquid level of the liquid refrigerant is predicted to some extent from the temperature in the compressor 10 and the solubility of the refrigerant in the refrigeration oil. Since the temperature within 10 is controlled to 20 ° C. from point A to point B, the input to the crankcase heater 29 can be minimized. As described above, in the present embodiment, the compressor 10 is heated by the crankcase heater 29 only when there is a large amount of liquid refrigerant, that is, when the solubility of the refrigerant in the refrigeration oil is high, so fine control can be performed. Particularly in summer, since the outside air temperature is high, it is not necessary to heat the crankcase heater 29 excessively. Therefore, the control according to the present embodiment is effective in saving power consumption.

Embodiment 3 FIG.
FIG. 7 is a partial cross-sectional view showing the compressor in the third embodiment, in which the operation of the compressor 10 is controlled by the oil level detected by the oil level detection device. In FIG. 7, the same components as those in FIG.
In FIG. 7, 34 is an oil level detection device installed in the compressor 10. Further, the control device 32 in FIG. 7 turns on the power of the crankcase heater 29 when the height of the liquid refrigerant detected by the oil level detection device 34 is higher than a predetermined height, and is lower than the predetermined height. In this case, the crankcase heater 29 is turned off.
As described above, by directly detecting the height of the liquid coolant level, the power of the crankcase heater 29 is controlled to be turned on and off, so that finer control can be achieved and energy saving can be achieved.

It is a refrigerant circuit figure which shows the air conditioning apparatus in Embodiment 1 of this invention. It is a fragmentary sectional view of the compressor which shows Embodiment 1 of this invention. It is an expanded sectional view of the charge part in the compressor which shows Embodiment 1 of this invention. It is a solubility curve of the refrigerant | coolant in the refrigerating machine oil used in Embodiment 2 of this invention. It is a fragmentary sectional view of the compressor which shows Embodiment 2 of this invention. It is a flowchart which shows the heating control of the compressor in Embodiment 2 of this invention. It is a fragmentary sectional view of the compressor which shows Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat source machine, 2 Indoor unit, 3 1st connection piping, 4 2nd connection piping, 5 Heat source machine side heat exchanger, 6 1st operation valve, 7 2nd operation valve, 8 Accumulator, 9 Oil separation , 10 compressor, 11 four-way valve, 12 flow regulator, 13 use side heat exchanger, 21 sealed container, 22 motor, 23 spindle, 24 compression element, 25 suction pipe, 26 discharge pipe, 27 charging section, 28 lead wire , 29 Crankcase heater, 30 Oil reservoir space, 31 Crankcase heater temperature sensor, 32 Control device, 33 Compressor temperature sensor, 34 Oil level detection device

Claims (4)

An air conditioner and a refrigerating apparatus in which an existing air conditioner using PAG oil as a refrigerating machine oil and an existing pipe of the refrigerating apparatus are reused and replaced with a heat source machine of an electric heat pump system using a refrigerating machine oil other than PAG oil. A heating unit that heats the compressor built in the heat source unit from the outside, and after heating the compressor by the heating unit, the conductor is energized in a charging unit connected to a motor in the compressor to compress the compression An air conditioner and a refrigeration apparatus, characterized in that a liquid level of liquid accumulated at the bottom of the compressor when the compressor is started is lower than the conductor. The controller includes temperature detection means for detecting the temperature in the compressor, and the control device calculates the solubility of the refrigerant in the refrigeration oil in the compressor based on the detected temperature, and the calculated value is smaller than a preset value. It controls so that it may become. The air conditioning apparatus and refrigeration apparatus of Claim 1 characterized by the above-mentioned. The air conditioner and the refrigeration apparatus according to claim 1, wherein an oil level detection device is provided in the compressor, and the control device controls a heating unit based on the detected oil level height. The air-conditioning apparatus and refrigeration apparatus according to any one of claims 1 to 3, wherein the refrigerant is R410A.

Images