WO2011070917A1 - Air conditioner and method for detecting amount of refrigerant in air conditioner - Google Patents
Air conditioner and method for detecting amount of refrigerant in air conditioner Download PDFInfo
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- WO2011070917A1 WO2011070917A1 PCT/JP2010/071064 JP2010071064W WO2011070917A1 WO 2011070917 A1 WO2011070917 A1 WO 2011070917A1 JP 2010071064 W JP2010071064 W JP 2010071064W WO 2011070917 A1 WO2011070917 A1 WO 2011070917A1
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- Prior art keywords
- refrigerant
- pressure
- temperature
- receiver
- air conditioner
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- 239000003507 refrigerant Substances 0.000 title claims abstract description 221
- 238000000034 method Methods 0.000 title abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 82
- 238000001514 detection method Methods 0.000 claims abstract description 66
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 46
- 238000010438 heat treatment Methods 0.000 claims abstract description 31
- 238000010586 diagram Methods 0.000 claims abstract description 22
- 230000006837 decompression Effects 0.000 claims abstract description 11
- 238000001816 cooling Methods 0.000 claims description 15
- 230000000630 rising effect Effects 0.000 claims description 3
- 239000011555 saturated liquid Substances 0.000 description 13
- 230000007812 deficiency Effects 0.000 description 4
- 238000004781 supercooling Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000004378 air conditioning Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B45/00—Arrangements for charging or discharging refrigerant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/04—Refrigerant level
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
Definitions
- the present invention relates to an air conditioner that can always be filled with an optimum amount of refrigerant at the time of installation, and a refrigerant amount detection method for the air conditioner.
- a multi-type air conditioner used for air conditioning of buildings and the like includes a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve for heating, a receiver and an outdoor fan, an indoor heat exchanger, A plurality of indoor units equipped with a cooling expansion valve, an indoor fan, and the like are connected locally via a gas refrigerant pipe and a liquid refrigerant pipe.
- a pipe length that connects between the outdoor unit and the indoor unit when the outdoor unit is preliminarily filled with a predetermined amount of refrigerant and the air conditioner is installed in the field and then trial run is performed.
- an insufficient amount of refrigerant is additionally charged according to the number of indoor units connected.
- the amount of refrigerant to be added is always stored in the receiver in the refrigerant circuit during the refrigerant charging operation.
- a liquid level detection circuit is provided for detecting that the incoming liquid refrigerant has reached a predetermined liquid level, and the liquid level detection circuit detects that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver.
- a bypass circuit is connected to a compressor suction side from a predetermined height position of a receiver, and an on-off valve, a pressure reducing mechanism, and a temperature detection unit are provided in the bypass circuit.
- the technique disclosed in Patent Document 2 is provided with an on-off valve, a pressure reducing mechanism, a heating unit, and a temperature detection unit in the bypass circuit, and when the saturated gas refrigerant is taken out from the receiver to the bypass circuit; When saturated liquid refrigerant is taken out, measure the refrigerant temperature after depressurization, and determine the amount of refrigerant by detecting that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver from the temperature difference It is what you do.
- JP 2002-350014 A Japanese Patent No. 3719246
- the one disclosed in Patent Document 2 is provided with a heating unit that heats the refrigerant decompressed by the decompression mechanism in the liquid level detection circuit, and the refrigerant taken out from the receiver is in a gas state
- the temperature rise due to heating is large, and in the liquid state, the heat energy from heating is consumed as latent heat of evaporation and the temperature rise is small, so that a sufficient temperature difference can be secured to improve detection accuracy. It is a thing.
- it is indispensable to install a heating unit in the liquid level detection circuit there is a problem that the configuration becomes complicated.
- the present invention has been made in view of such circumstances, and it is possible to always detect the refrigerant charging amount with high accuracy without providing a heating unit in the liquid level detection circuit, and the refrigerant amount of the air conditioner.
- An object is to provide a detection method.
- the air conditioner and the refrigerant amount detection method for the air conditioner of the present invention employ the following means. That is, the air conditioner according to the first aspect of the present invention includes an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver for storing liquid refrigerant, and the like, an indoor heat exchanger, and a cooling expansion.
- an air conditioner that connects an indoor unit having a valve or the like with a gas refrigerant pipe and a liquid refrigerant pipe to form a closed-cycle refrigerant circuit, the predetermined height position of the receiver and the suction side of the compressor
- a liquid level detection circuit provided with an on-off valve and a pressure reduction mechanism in a bypass circuit connecting between them, a temperature detection unit for detecting the temperature of the refrigerant depressurized by the pressure reduction mechanism flowing in the liquid level detection circuit, and in the receiver
- the intermediate pressure is controlled to a pressure at which the superheat degree is 5 deg or more of the saturated gas temperature with a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is in a region that rises to the right.
- detection By detecting the temperature of the refrigerant taken out for the road by the temperature detecting unit, and a, a refrigerant amount detecting unit determines refrigerant charge based on temperature.
- a liquid level detection circuit in which an on-off valve and a pressure reducing mechanism are provided in a bypass circuit that connects between a predetermined height position of the receiver and the suction side of the compressor, and a liquid level detection circuit
- a temperature detection unit for detecting the temperature of the refrigerant decompressed by the decompression mechanism flowing through the intermediate pressure in the receiver, and the saturation gas line of the pressure-enthalpy diagram with a superheat degree of 5 deg.
- the pressure of the refrigerant is controlled to a pressure that rises to the right, and the temperature of the refrigerant taken out from the receiver to the liquid level detection circuit is detected by the temperature detection unit, so that the refrigerant filling amount is determined based on the temperature.
- a refrigerant amount detection unit that performs an intermediate pressure in which the degree of superheat is not less than 5 deg.
- the low-pressure saturated gas temperature and the slope of the saturated gas line in the pressure-enthalpy diagram is an upward-sloping region.
- the refrigerant charging amount can be detected with high accuracy by ensuring a sufficient temperature difference without being influenced by the refrigerant discharge side pressure (high pressure) and without providing the refrigerant heating section. It is possible to stably operate the air conditioner by filling the optimal amount of refrigerant without any shortage.
- the refrigerant amount detection unit includes an intermediate pressure sensor, a temperature sensor that detects a refrigerant temperature taken out by the liquid level detection circuit, Alternatively, the intermediate pressure is detected from a detected value from a high-pressure sensor and a temperature sensor that detects the degree of refrigerant supercooling at the outlet of the outdoor heat exchanger or a converted value thereof, and the rotational speed of the compressor is applied to the outdoor heat exchanger.
- the intermediate pressure in the receiver is controlled to the pressure by controlling the rotational speed of an outdoor fan that ventilates the outside air, the opening degree of the expansion valve for heating, or the like.
- the refrigerant amount detection unit detects the refrigerant temperature taken out by the intermediate pressure sensor, the liquid level detection circuit, or the refrigerant supercooling at the outlet of the high pressure sensor and the outdoor heat exchanger.
- the intermediate pressure is detected from the detected value from the temperature sensor, etc. that detects the degree or the converted value, and the rotational speed of the compressor, the rotational speed of the outdoor fan that ventilates the outdoor air to the outdoor heat exchanger, or the opening of the heating expansion valve Etc., and the intermediate pressure in the receiver is controlled to the above pressure. Therefore, the intermediate pressure in the receiver is changed to the rotational speed of the compressor, the outdoor fan that ventilates the outdoor air to the outdoor heat exchanger.
- the superheat degree is softer than 5 deg of the saturated gas temperature at low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is on the right For intermediate pressure to be the rising area Gosuru can. Therefore, it is possible to accurately detect the refrigerant filling amount by detecting the refrigerant temperature after decompression by the liquid level detection circuit without adding a refrigerant heating unit in hardware, and to fill the optimum amount of refrigerant without excess or deficiency. Can do.
- the air conditioner according to the first aspect of the present invention introduces hot gas discharged from the compressor between the discharge side of the compressor and the receiver in any of the air conditioners described above. And the hot gas bypass circuit for raising the intermediate pressure in the said receiver to the said pressure is provided.
- the hot gas for introducing the hot gas discharged from the compressor between the discharge side of the compressor and the receiver to raise the intermediate pressure in the receiver to the above pressure. Since a bypass circuit is provided, for example, even when the ambient pressure in the receiver does not rise to the above pressure under low ambient temperature conditions, a part of the hot gas is passed to the receiver via the hot gas bypass circuit. By introducing, the intermediate pressure can be controlled to the above pressure. Therefore, the refrigerant filling amount can be accurately detected even under a low outside air temperature condition, and the optimum amount of refrigerant can be filled. In addition, this makes it possible to easily increase the pressure even under a low outside air temperature condition, and can be effectively applied to high pressure control or the like during cooling at a low outside air temperature.
- the refrigerant amount detection method for an air conditioner includes an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver storing liquid refrigerant, and the like, and indoor heat exchange.
- the refrigerant amount detection method of the air conditioner that connects the indoor unit having an air conditioner, an expansion valve for cooling, etc. with a gas refrigerant pipe and a liquid refrigerant pipe, and constitutes a closed cycle refrigerant circuit
- the intermediate pressure in the receiver is controlled to a pressure at which the superheat degree is at least 5 deg of the saturated gas temperature with a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram rises to the right. From the predetermined height position of the receiver to a liquid level detecting circuit connected to the compressor suction side, and detecting the temperature of the refrigerant decompressed to a low pressure state in the liquid level detecting circuit, Determine.
- the intermediate pressure of the refrigerant in the receiver is equal to or greater than 5 deg. Of the saturated gas temperature with a superheat degree of low pressure, and the saturated gas line of the pressure-enthalpy diagram.
- the pressure is controlled so that the slope becomes an upwardly rising region, and the intermediate-pressure refrigerant is taken out from the predetermined height position of the receiver to the liquid level detection circuit connected to the compressor suction side, and the low pressure in the liquid level detection circuit Since the refrigerant charging amount is determined by detecting the temperature of the refrigerant whose pressure has been reduced to the state, the degree of superheat is not less than 5 deg.
- the refrigerant temperature after decompression is detected when the saturated gas refrigerant is taken out from the receiver controlled in the intermediate pressure where the inclination is an area where the inclination rises to the right and when the saturated liquid refrigerant is taken out, respectively.
- the temperature difference It is possible to detect that the accumulated predetermined liquid level of the liquid refrigerant in Luo the receiver. Therefore, the refrigerant filling amount can be detected with high accuracy by ensuring the temperature difference sufficiently without being influenced by the discharge pressure (high pressure) of the refrigerant and without providing a portion for heating the refrigerant. It is possible to fill the air conditioner with an optimal amount of refrigerant without excess or deficiency.
- the degree of superheat is not less than 5 deg of the low pressure saturated gas temperature, and the slope of the saturated gas line in the pressure-enthalpy diagram rises to the right.
- the saturated gas refrigerant is taken out from the receiver controlled to the intermediate pressure that becomes the region of the above and when the saturated liquid refrigerant is taken out, the refrigerant temperature after depressurization is detected, and the difference in temperature is detected in the receiver. Since it is possible to detect that the liquid refrigerant of a predetermined liquid level has accumulated, the above temperature difference is sufficiently ensured without being influenced by the refrigerant discharge side pressure and without providing a refrigerant heating section. Thus, the refrigerant charge amount can be detected with high accuracy, and the optimum amount of refrigerant can be charged without excess or deficiency, and the air conditioner can be operated stably.
- the air conditioner shown in FIG. 1 it is a pressure-enthalpy diagram when the intermediate pressure in the receiver is set to the vicinity of the maximum enthalpy with a saturated gas line by the intermediate pressure control.
- FIG. 1 shows a refrigerant circuit diagram of an air conditioner according to the first embodiment of the present invention.
- the air conditioner 1 is a multi-type air conditioner that is applied to air conditioning of buildings and the like, and includes an outdoor unit 2 and a plurality of indoor units 3 connected in parallel to each other (FIG. 1 shows only one unit). It is composed of).
- a compressor 10 that compresses the refrigerant, a four-way switching valve 11 that switches the circulation direction of the refrigerant, an outdoor heat exchanger 12 that exchanges heat between the outside air and the refrigerant, and the outside air are passed through the outdoor heat exchanger 12.
- An outdoor fan 13 for heating, an electric expansion valve for heating (heating expansion valve) 14, a receiver 15 for accumulating condensed liquid refrigerant, and the like are disposed, and a compressor 10, a four-way switching valve 11, an outdoor heat exchanger 12,
- the outdoor refrigerant circuit 17 is configured by sequentially connecting the heating electric expansion valve 14 and the receiver 15 via the refrigerant pipe 16.
- an indoor heat exchanger 20 Inside the indoor unit 3, an indoor heat exchanger 20, an indoor fan 21 that circulates indoor air through the indoor heat exchanger 20, a cooling electric expansion valve (cooling expansion valve) 22, and the like are disposed.
- the indoor unit 3 and the outdoor unit 2 are connected via a gas refrigerant pipe 23 and a liquid refrigerant pipe 24, whereby a closed-cycle refrigerant circuit 25 is configured.
- the plurality of indoor units 3 are connected in parallel to each other via the gas refrigerant pipe 23 and the liquid refrigerant pipe 24 branched from the gas refrigerant pipe 23 and the liquid refrigerant pipe 24.
- the air conditioner 1 circulates the refrigerant discharged from the compressor 10 to the outdoor heat exchanger 12 side via the four-way switching valve 11, and receives the receiver 15, the cooling electric expansion valve 22, the indoor heat exchanger 20, and the four-way switching valve 11.
- the outdoor heat exchanger 12 functions as a condenser
- the indoor heat exchanger 20 functions as an evaporator so that a cooling operation can be performed.
- the refrigerant discharged from the compressor 10 is circulated to the indoor heat exchanger 20 side via the four-way switching valve 11, and the receiver 15, the heating electric expansion valve 14, the outdoor heat exchanger 12, the four-way switching valve 11, and
- the indoor heat exchanger 20 functions as a condenser
- the outdoor heat exchanger 12 functions as an evaporator so that heating operation can be performed.
- the lengths of the gas refrigerant pipe 23 and the liquid refrigerant pipe 24 that connect the outdoor unit 2 and the indoor unit 3 vary depending on the environment in which the air conditioner 1 is installed. For this reason, when the outdoor unit 2 is preliminarily filled with a predetermined amount of refrigerant and the air conditioner 1 is installed in the field, the length of the pipe connecting the outdoor unit 2 and the indoor unit 3 when the test operation is performed Insufficient amount of refrigerant must be charged according to the number of indoor units 3 connected. When the refrigerant is additionally charged, the following liquid level detection circuit 30 and the refrigerant amount detection unit 35 are incorporated in order to always be able to charge an appropriate amount of refrigerant without depending on the construction level at the site. Yes.
- the liquid level detection circuit 30 includes a bypass circuit 31 that can take out the refrigerant from a predetermined height position in the receiver 15 to the suction side of the compressor 10, and a capillary tube, an expansion valve, and the like provided in the bypass circuit 31. And a temperature sensor (temperature detection unit) 34 such as a thermistor for detecting the refrigerant temperature after being taken out by the bypass circuit 31 and decompressed by the decompression mechanism 32. .
- the refrigerant amount detection unit 35 is for determining whether or not an appropriate amount of refrigerant is filled based on the temperature detected by the temperature sensor 34.
- the liquid refrigerant is accumulated in the receiver 15, The liquid level reaches the height position at which the bypass circuit 31 is opened, and the detected temperature from the temperature sensor 34 when the saturated liquid refrigerant is taken out to the bypass circuit 31 and the liquid refrigerant at a predetermined height position.
- Whether or not an appropriate amount of refrigerant has been charged based on the temperature difference from the temperature detected by the temperature sensor 34 when the saturated gas refrigerant is taken out from the receiver 15 to the bypass circuit 31 from the receiver 15. Can be determined.
- the refrigerant amount detection unit 35 sets the intermediate pressure in the receiver 15 to 5 degrees or more of the saturated gas temperature at which the superheat is low, and the slope of the saturated gas line in the pressure-enthalpy diagram is on the right. It has a function to control the pressure to become a shoulder rise area. This is because, for example, the intermediate pressure detected by the intermediate pressure sensor 36 is not less than 5 deg. Of the saturated gas temperature of the low pressure on the pressure-enthalpy diagram, and the slope of the saturated gas line rises to the right.
- the pressure is controlled by adjusting the rotational speed of the compressor 10, the rotational speed of the outdoor fan 13, or the opening degree of the heating electric expansion valve 14 so that the pressure becomes the same pressure.
- the intermediate pressure in the receiver 15 is a pressure obtained by using the detected temperature from the temperature sensor 37 provided in the refrigerant take-out portion of the bypass circuit 31 as the saturated gas temperature of the refrigerant, as shown in FIG. 2. Or the refrigerant provided at the outlet of the high-pressure sensor 38 and the outdoor heat exchanger 12 provided in the discharge pipe of the compressor 10 as shown in FIG. On the basis of the detected value from the temperature sensor 39 that detects the degree of supercooling, the enthalpy may be converted into a saturated liquid pressure that is constant.
- the refrigerant circuit 25 is operated as a cooling cycle.
- the outdoor fan 13 is controlled so that the condensation pressure in the outdoor heat exchanger 12 becomes a predetermined value, and at the outlet of the indoor heat exchanger 20, a predetermined superheat degree is given to the refrigerant.
- the opening degree of the electric expansion valve 22 is controlled.
- the refrigerant can be filled in the refrigerant circuit 25 in a state where the liquid refrigerant pipe 24 is filled with the liquid refrigerant having a predetermined density.
- the electromagnetic opening / closing valve 33 of the liquid level detection circuit 30 is open.
- the refrigerant circulation amount in the refrigerant circuit 25 is gradually increased, and the liquid level of the refrigerant in the receiver 15 gradually rises. This is because the amount of refrigerant evaporated in the indoor heat exchanger 20 and the amount of refrigerant condensed in the outdoor heat exchanger 12 are balanced, and the receiver 15 is filled with the amount of refrigerant charged from the outside. Liquid refrigerant gradually accumulates. At this time, the saturated gas refrigerant in the receiver 15 flows to the bypass circuit 31 until the liquid refrigerant is accumulated in the receiver 15 up to a height position where the bypass circuit 31 of the liquid level detection circuit 30 is opened. That is, when the liquid level of the liquid refrigerant rises to the height position where the bypass circuit 31 is opened, the saturated liquid refrigerant flows into the bypass circuit 31.
- the saturated gas refrigerant or saturated liquid refrigerant is decompressed to a low pressure state by the decompression mechanism 33, and the temperature drops.
- the refrigerant amount detection unit 35 looks at the temperature difference between the temperature drop from the saturated gas refrigerant state and the temperature drop from the saturated liquid refrigerant state. It is determined that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15, and it is determined that the required amount of refrigerant has been filled. At this point, the refrigerant filling operation is terminated.
- the temperature difference is sufficiently secured.
- the saturated liquid refrigerant that has flowed into the bypass circuit 31 is decompressed by the decompression mechanism 33 to become a gas-liquid two-phase state and evaporates, so that the temperature detected by the temperature sensor 34 rapidly decreases.
- the refrigerant flowing in the saturated gas state increases the discharge-side pressure of the compressor 10 due to, for example, an increase in the outside air temperature, and the strip pressure in which the slope of the saturated gas line in the pressure-enthalpy diagram increases to the left.
- a gas-liquid two-phase state occurs when the pressure is reduced by the pressure reducing mechanism 33. In this case, a rapid temperature drop due to the evaporation of the refrigerant is detected, and the refrigerant amount detecting unit 35 is
- the liquid refrigerant may erroneously be determined to have reached a predetermined liquid level.
- the intermediate pressure of the refrigerant in the receiver 15 is not less than 5 deg. Of the saturated gas temperature of the low pressure, and the saturated gas line on the pressure-enthalpy diagram. Since the saturated gas refrigerant in this state is taken out to the bypass circuit 31 and is depressurized to lower the temperature, the saturation of the refrigerant depressurized to low pressure is controlled. It is possible to always secure a superheat degree SH of 5 deg or more with respect to the gas temperature.
- FIG. 4 is a pressure-enthalpy diagram when the pressure in the receiver 15 is set to the vicinity of the maximum enthalpy with a saturated gas line.
- R410A refrigerant the refrigerant is taken out from the vicinity of 2 MPa to the bypass circuit 31 and the temperature is lowered.
- the pressure-enthalpy diagram at the time of the actual refrigerant filling operation is as shown in FIG. That is, although the discharge side pressure of the compressor 10 is higher than the intermediate pressure in the receiver 15, the intermediate pressure in the receiver 15 flows into the intermediate pressure sensor 36 and the bypass circuit 31 without being influenced by this high pressure.
- the intermediate pressure is detected from the detected value from the temperature sensor 37 for detecting the temperature, the temperature sensor 39 for detecting the degree of refrigerant supercooling at the outlet of the high pressure sensor 38 and the outdoor heat exchanger 13 or the converted value thereof.
- the rotational speed, the rotational speed of the outdoor fan 13 that ventilates the outdoor air to the outdoor heat exchanger 12, or the opening degree of the heating expansion valve 14, etc. the liquid refrigerant in the receiver 15 is controlled by the above pressure. It is on the saturated liquid line.
- the saturated gas refrigerant or the saturated liquid refrigerant is taken out from the receiver 15 to the bypass circuit 31 and is decompressed by the decompression mechanism 33 to decrease the temperature, and the temperature is detected by the temperature sensor 34 to detect the refrigerant amount from the temperature difference.
- the amount of refrigerant can be accurately detected via the unit 35. Therefore, according to the present embodiment, the temperature difference is sufficiently reduced without being influenced by the discharge side pressure (high pressure) of the refrigerant that is influenced by the outside air temperature or the like and without providing the refrigerant heating unit in the bypass circuit 31. It is possible to secure and detect the refrigerant filling amount with high accuracy, and to fill the optimum amount of refrigerant without excess and deficiency and to operate the air conditioner stably.
- FIG. 6 a part of the hot gas discharged from the compressor 10 can be introduced into the receiver 15 between the discharge pipe from the compressor 10 and the receiver 15.
- the hot gas bypass circuit 40 is provided.
- the hot gas bypass circuit 40 is provided with an electromagnetic opening / closing valve 41 and a pressure reducing mechanism 42 such as a capillary tube or an expansion valve.
- the hot gas bypass circuit 40 in which the electromagnetic on-off valve 41 and the pressure reducing mechanism 42 are interposed is provided between the discharge side of the compressor 10 and the receiver 15, and is discharged from the compressor 10 into the receiver 15.
- the electromagnetic on-off valve 41 can be used even when the intermediate pressure in the receiver 15 does not rise to the above-described pressure during the refrigerant charging operation, for example, under a low outside air temperature condition. Is opened, and hot gas is introduced into the receiver 15 via the hot gas bypass circuit 40, whereby the intermediate pressure in the receiver 15 can be controlled to the above-described pressure.
- the refrigerant charging amount can be detected with high accuracy, and the optimal amount of refrigerant can be charged.
- This also makes it possible to easily increase the pressure even under low outside air temperature conditions.
- the control for reducing the pressure is easy and the control for increasing the pressure is difficult.
- the pressure control at the low outside air temperature can be facilitated.
- the hot gas bypass circuit 40 can be effectively applied not only to the refrigerant charging operation but also to high pressure control at the time of cooling at a low outside air temperature, and contributes to the expansion of the cooling operation range by the air conditioner 1. Can do.
- the bypass circuit 31 of the liquid level detection circuit 30 is inserted and connected to the receiver 15 from the upper surface of the receiver 15, but the bypass circuit 31 has a predetermined height in the receiver 15. It is only necessary to be connected so as to be opened at a position, and therefore, it may be inserted so as to be opened from a side surface or a lower surface of the receiver 15 so as to be opened at a predetermined height position.
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Abstract
Provided are an air conditioner and a method for detecting the amount of refrigerant in the air conditioner, wherein the amount of refrigerant charge can be consistently detected with high accuracy, without providing a heating unit on a liquid level detection circuit. An air conditioner (1) to which an outdoor unit (2) and an indoor unit (3) are connected, is provided with a liquid level detection circuit (30) wherein an opening and closing valve (33) and a decompression mechanism (32) are provided on a bypass circuit (31) that connects a predetermined height position within a receiver (15) to the suction side of a compressor (10); a temperature detection unit (34) for detecting the temperature of refrigerant which passes through the liquid level detection circuit (30) and which is decompressed by a decompression mechanism (32); and a refrigerant amount detection unit (35) which controls an intermediate pressure within the receiver (15) to a pressure at which the superheated temperature is at least 5 degrees higher than the temperature of a low-pressure saturated gas, and a saturated gas line extends diagonally to the upper right in a pressure-enthalpy diagram, said refrigerant amount detection unit detecting the temperature of refrigerant transferred from the receiver (15) to the liquid level detection circuit (30) with a temperature detection unit (34) so as to determine the amount of refrigerant charge on the basis of the temperature.
Description
本発明は、据付け時に、常に最適な量の冷媒を充填することができる空気調和機および空気調和機の冷媒量検出方法に関するものである。
The present invention relates to an air conditioner that can always be filled with an optimum amount of refrigerant at the time of installation, and a refrigerant amount detection method for the air conditioner.
ビル等の空調に用いられるマルチタイプの空気調和機は、圧縮機、四方切換弁、室外熱交換器、暖房用膨張弁、レシーバおよび室外ファン等を備えている室外機と、室内熱交換器、冷房用膨張弁および室内ファン等を備えている複数台の室内機との間を、現地においてガス冷媒配管および液冷媒配管を介して接続するようにしている。このような空気調和機では、予め室外機に所定量の冷媒を充填しておき、現地において空気調和機を据付けした後、試運転するときに、室外機と室内機との間を接続する配管長さや室内機の接続台数等に応じて不足量の冷媒を追加充填するようにしている。
A multi-type air conditioner used for air conditioning of buildings and the like includes a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve for heating, a receiver and an outdoor fan, an indoor heat exchanger, A plurality of indoor units equipped with a cooling expansion valve, an indoor fan, and the like are connected locally via a gas refrigerant pipe and a liquid refrigerant pipe. In such an air conditioner, a pipe length that connects between the outdoor unit and the indoor unit when the outdoor unit is preliminarily filled with a predetermined amount of refrigerant and the air conditioner is installed in the field and then trial run is performed. In addition, an insufficient amount of refrigerant is additionally charged according to the number of indoor units connected.
かかる空気調和機において、追加する冷媒の充填量を現地の工事レベルに依存することなく、常に適正な量の冷媒を充填できるようにするため、冷媒充填運転時に、冷媒回路中のレシーバ内に溜まってくる液冷媒が所定の液面レベルに達したことを検出する液面検出回路を設け、この液面検出回路によりレシーバ内に所定液面の液冷媒が溜まったことが検出されたことを以って、冷媒回路内に必要量の冷媒が充填されていると判定するようにした技術が特許文献1(図1参照),特許文献2(図1参照)により開示されている。
In such an air conditioner, in order to always be able to charge an appropriate amount of refrigerant without depending on the local construction level, the amount of refrigerant to be added is always stored in the receiver in the refrigerant circuit during the refrigerant charging operation. A liquid level detection circuit is provided for detecting that the incoming liquid refrigerant has reached a predetermined liquid level, and the liquid level detection circuit detects that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver. Thus, a technique for determining that a necessary amount of refrigerant is filled in the refrigerant circuit is disclosed in Patent Document 1 (see FIG. 1) and Patent Document 2 (see FIG. 1).
この特許文献1に示された技術は、レシーバの所定高さ位置から圧縮機吸入側にバイパス回路を接続し、このバイパス回路中に開閉弁、減圧機構、温度検出部を設けたものである。特許文献2に示された技術は、バイパス回路中に開閉弁、減圧機構、加熱部、温度検出部を設けたものであり、バイパス回路にレシーバから飽和状態のガス冷媒が取出された場合と、飽和状態の液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を測定し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することにより、冷媒量を判定するようにしたものである。
In the technique disclosed in Patent Document 1, a bypass circuit is connected to a compressor suction side from a predetermined height position of a receiver, and an on-off valve, a pressure reducing mechanism, and a temperature detection unit are provided in the bypass circuit. The technique disclosed in Patent Document 2 is provided with an on-off valve, a pressure reducing mechanism, a heating unit, and a temperature detection unit in the bypass circuit, and when the saturated gas refrigerant is taken out from the receiver to the bypass circuit; When saturated liquid refrigerant is taken out, measure the refrigerant temperature after depressurization, and determine the amount of refrigerant by detecting that the liquid refrigerant of the predetermined liquid level has accumulated in the receiver from the temperature difference It is what you do.
しかしながら、特許文献1に開示されたものの場合、外気温等が高く、圧縮機の吐出側圧力(高圧)が高くなって、圧力-エンタルピ線図上の飽和ガス線の傾きが左肩上がりとなる圧力条件下では、飽和状態のガス冷媒を取出して減圧したとき、気液二相状態となることがあり、この場合、冷媒の急激な温度降下を検出してしまい、液冷媒が所定液面レベルに到達していると誤判定してしまうおそれがあり、検出精度を確保できないという課題があった。
However, in the case of the one disclosed in Patent Document 1, the outside air temperature is high, the discharge side pressure (high pressure) of the compressor is high, and the slope of the saturated gas line on the pressure-enthalpy diagram increases to the left. Under certain conditions, when a saturated gas refrigerant is taken out and depressurized, a gas-liquid two-phase state may occur.In this case, a sudden temperature drop of the refrigerant is detected, and the liquid refrigerant reaches a predetermined liquid level. There is a possibility that it may be erroneously determined that it has arrived, and there is a problem that detection accuracy cannot be secured.
一方、特許文献2に開示されたものは、上記課題を解決するため、液面検出回路に減圧機構で減圧された冷媒を加熱する加熱部を設け、レシーバから取出された冷媒がガス状態の場合は加熱による温度上昇が大きく、液状態の場合は加熱による熱エネルギーが蒸発潜熱として消費されて温度上昇が小さいことを利用し、温度差を十分に確保できるようにして、検出精度を向上させるようにしたものである。しかし、液面検出回路に加熱部を設置することが不可欠となるため、構成が複雑化するという問題があった。特許文献1,2のいずれのものにおいても、低外気温時等で吐出側圧力(高圧圧力)が十分に上昇されない場合、レシーバから取出されるガス冷媒の過熱度が確保できなくなり、検出精度が低下するという問題が内在されている。
On the other hand, in order to solve the above problem, the one disclosed in Patent Document 2 is provided with a heating unit that heats the refrigerant decompressed by the decompression mechanism in the liquid level detection circuit, and the refrigerant taken out from the receiver is in a gas state The temperature rise due to heating is large, and in the liquid state, the heat energy from heating is consumed as latent heat of evaporation and the temperature rise is small, so that a sufficient temperature difference can be secured to improve detection accuracy. It is a thing. However, since it is indispensable to install a heating unit in the liquid level detection circuit, there is a problem that the configuration becomes complicated. In any one of Patent Documents 1 and 2, when the discharge side pressure (high pressure) is not sufficiently increased at low outside air temperature, the degree of superheat of the gas refrigerant taken out from the receiver cannot be secured, and the detection accuracy is improved. The problem of decline is inherent.
本発明は、このような事情に鑑みてなされたものであって、液面検出回路に加熱部を設けることなく、冷媒充填量を常に高精度で検出できる空気調和機および空気調和機の冷媒量検出方法を提供することを目的とする。
The present invention has been made in view of such circumstances, and it is possible to always detect the refrigerant charging amount with high accuracy without providing a heating unit in the liquid level detection circuit, and the refrigerant amount of the air conditioner. An object is to provide a detection method.
上記した課題を解決するために、本発明の空気調和機および空気調和機の冷媒量検出方法は、以下の手段を採用する。
すなわち、本発明の第1の態様にかかる空気調和機は、圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を有する室外機と、室内熱交換器、冷房用膨張弁等を有する室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、前記レシーバの所定高さ位置と前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を設けた液面検出回路と、前記液面検出回路を流れる前記減圧機構によって減圧された冷媒の温度を検出する温度検出部と、前記レシーバ内の中間圧力を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該レシーバ内から前記液面検出回路に取出された冷媒の温度を前記温度検出部で検出することにより、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている。 In order to solve the above-described problems, the air conditioner and the refrigerant amount detection method for the air conditioner of the present invention employ the following means.
That is, the air conditioner according to the first aspect of the present invention includes an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver for storing liquid refrigerant, and the like, an indoor heat exchanger, and a cooling expansion. In an air conditioner that connects an indoor unit having a valve or the like with a gas refrigerant pipe and a liquid refrigerant pipe to form a closed-cycle refrigerant circuit, the predetermined height position of the receiver and the suction side of the compressor A liquid level detection circuit provided with an on-off valve and a pressure reduction mechanism in a bypass circuit connecting between them, a temperature detection unit for detecting the temperature of the refrigerant depressurized by the pressure reduction mechanism flowing in the liquid level detection circuit, and in the receiver The intermediate pressure is controlled to a pressure at which the superheat degree is 5 deg or more of the saturated gas temperature with a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is in a region that rises to the right. detection By detecting the temperature of the refrigerant taken out for the road by the temperature detecting unit, and a, a refrigerant amount detecting unit determines refrigerant charge based on temperature.
すなわち、本発明の第1の態様にかかる空気調和機は、圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を有する室外機と、室内熱交換器、冷房用膨張弁等を有する室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、前記レシーバの所定高さ位置と前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を設けた液面検出回路と、前記液面検出回路を流れる前記減圧機構によって減圧された冷媒の温度を検出する温度検出部と、前記レシーバ内の中間圧力を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該レシーバ内から前記液面検出回路に取出された冷媒の温度を前記温度検出部で検出することにより、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている。 In order to solve the above-described problems, the air conditioner and the refrigerant amount detection method for the air conditioner of the present invention employ the following means.
That is, the air conditioner according to the first aspect of the present invention includes an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver for storing liquid refrigerant, and the like, an indoor heat exchanger, and a cooling expansion. In an air conditioner that connects an indoor unit having a valve or the like with a gas refrigerant pipe and a liquid refrigerant pipe to form a closed-cycle refrigerant circuit, the predetermined height position of the receiver and the suction side of the compressor A liquid level detection circuit provided with an on-off valve and a pressure reduction mechanism in a bypass circuit connecting between them, a temperature detection unit for detecting the temperature of the refrigerant depressurized by the pressure reduction mechanism flowing in the liquid level detection circuit, and in the receiver The intermediate pressure is controlled to a pressure at which the superheat degree is 5 deg or more of the saturated gas temperature with a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is in a region that rises to the right. detection By detecting the temperature of the refrigerant taken out for the road by the temperature detecting unit, and a, a refrigerant amount detecting unit determines refrigerant charge based on temperature.
本発明の第1の態様によれば、レシーバの所定高さ位置と圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を設けた液面検出回路と、液面検出回路を流れる減圧機構によって減圧された冷媒の温度を検出する温度検出部と、レシーバ内の中間圧を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該レシーバ内から液面検出回路に取出された冷媒の温度を温度検出部で検出することにより、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えているため、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる中間圧に制御されたレシーバ内から飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することができる。従って、冷媒の吐出側圧力(高圧)に左右されることなく、また、冷媒加熱部を設けることなく、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。
According to the first aspect of the present invention, a liquid level detection circuit in which an on-off valve and a pressure reducing mechanism are provided in a bypass circuit that connects between a predetermined height position of the receiver and the suction side of the compressor, and a liquid level detection circuit A temperature detection unit for detecting the temperature of the refrigerant decompressed by the decompression mechanism flowing through the intermediate pressure in the receiver, and the saturation gas line of the pressure-enthalpy diagram with a superheat degree of 5 deg. The pressure of the refrigerant is controlled to a pressure that rises to the right, and the temperature of the refrigerant taken out from the receiver to the liquid level detection circuit is detected by the temperature detection unit, so that the refrigerant filling amount is determined based on the temperature. And a refrigerant amount detection unit that performs an intermediate pressure in which the degree of superheat is not less than 5 deg. Of the low-pressure saturated gas temperature and the slope of the saturated gas line in the pressure-enthalpy diagram is an upward-sloping region. In a controlled receiver? When the saturated gas refrigerant is taken out and when the saturated liquid refrigerant is taken out, the refrigerant temperature after depressurization is detected, and from the temperature difference, it is detected that the liquid refrigerant at the predetermined liquid level has accumulated in the receiver. can do. Therefore, the refrigerant charging amount can be detected with high accuracy by ensuring a sufficient temperature difference without being influenced by the refrigerant discharge side pressure (high pressure) and without providing the refrigerant heating section. It is possible to stably operate the air conditioner by filling the optimal amount of refrigerant without any shortage.
さらに、本発明の第1の態様の空気調和機は、上記の空気調和機において、前記冷媒量検出部は、中間圧センサ、前記液面検出回路に取出された冷媒温度を検出する温度センサ、あるいは高圧センサおよび前記室外熱交換器出口の冷媒過冷却度を検出する温度センサ等からの検出値またはその換算値から前記中間圧を検出し、前記圧縮機の回転数、前記室外熱交換器に外気を通風する室外ファンの回転数、または前記暖房用膨張弁の開度等を制御して、前記レシーバ内の中間圧を前記圧力に制御するように構成されている。
Furthermore, in the air conditioner according to the first aspect of the present invention, in the above air conditioner, the refrigerant amount detection unit includes an intermediate pressure sensor, a temperature sensor that detects a refrigerant temperature taken out by the liquid level detection circuit, Alternatively, the intermediate pressure is detected from a detected value from a high-pressure sensor and a temperature sensor that detects the degree of refrigerant supercooling at the outlet of the outdoor heat exchanger or a converted value thereof, and the rotational speed of the compressor is applied to the outdoor heat exchanger. The intermediate pressure in the receiver is controlled to the pressure by controlling the rotational speed of an outdoor fan that ventilates the outside air, the opening degree of the expansion valve for heating, or the like.
本発明の第1の態様によれば、冷媒量検出部が、中間圧センサ、液面検出回路に取出された冷媒温度を検出する温度センサ、あるいは高圧センサおよび室外熱交換器出口の冷媒過冷却度を検出する温度センサ等からの検出値またはその換算値から中間圧を検出し、圧縮機の回転数、室外熱交換器に外気を通風する室外ファンの回転数または暖房用膨張弁の開度等を制御して、レシーバ内の中間圧を上記圧力に制御するように構成されているため、レシーバ内の中間圧を、圧縮機の回転数、室外熱交換器に外気を通風する室外ファンの回転数、または暖房用膨張弁の開度等を制御することにより、ソフト的に過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる中間圧に制御することができる。従って、ハード的に冷媒加熱部を付設することなく、液面検出回路で減圧後の冷媒温度を検出することによって精度よく冷媒充填量を検出し、過不足のない最適量の冷媒を充填することができる。
According to the first aspect of the present invention, the refrigerant amount detection unit detects the refrigerant temperature taken out by the intermediate pressure sensor, the liquid level detection circuit, or the refrigerant supercooling at the outlet of the high pressure sensor and the outdoor heat exchanger. The intermediate pressure is detected from the detected value from the temperature sensor, etc. that detects the degree or the converted value, and the rotational speed of the compressor, the rotational speed of the outdoor fan that ventilates the outdoor air to the outdoor heat exchanger, or the opening of the heating expansion valve Etc., and the intermediate pressure in the receiver is controlled to the above pressure. Therefore, the intermediate pressure in the receiver is changed to the rotational speed of the compressor, the outdoor fan that ventilates the outdoor air to the outdoor heat exchanger. By controlling the rotational speed or the opening of the expansion valve for heating, etc., the superheat degree is softer than 5 deg of the saturated gas temperature at low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is on the right For intermediate pressure to be the rising area Gosuru can. Therefore, it is possible to accurately detect the refrigerant filling amount by detecting the refrigerant temperature after decompression by the liquid level detection circuit without adding a refrigerant heating unit in hardware, and to fill the optimum amount of refrigerant without excess or deficiency. Can do.
さらに、本発明の第1の態様の空気調和機は、上述のいずれかの空気調和機において、前記圧縮機の吐出側と前記レシーバとの間に、前記圧縮機から吐出されたホットガスを導入して前記レシーバ内の中間圧を前記圧力に上昇させるためのホットガスバイパス回路が設けられている。
Furthermore, the air conditioner according to the first aspect of the present invention introduces hot gas discharged from the compressor between the discharge side of the compressor and the receiver in any of the air conditioners described above. And the hot gas bypass circuit for raising the intermediate pressure in the said receiver to the said pressure is provided.
本発明の第1の態様によれば、圧縮機の吐出側とレシーバとの間に、圧縮機から吐出されたホットガスを導入してレシーバ内の中間圧を上記圧力に上昇させるためのホットガスバイパス回路が設けられているため、例えば低外気温条件下であって、レシーバ内の中間圧が上記圧力まで上昇しないような場合でも、ホットガスバイパス回路を介してホットガスの一部をレシーバに導入することにより、中間圧を上記圧力に制御することができる。従って、低外気温条件下であっても、精度よく冷媒充填量を検出することができ、最適量の冷媒を充填することができる。また、これによって、低外気温条件下でも容易に圧力を上昇させることが可能となり、低外気温冷房時の高圧制御等にも有効に適用することができる。
According to the first aspect of the present invention, the hot gas for introducing the hot gas discharged from the compressor between the discharge side of the compressor and the receiver to raise the intermediate pressure in the receiver to the above pressure. Since a bypass circuit is provided, for example, even when the ambient pressure in the receiver does not rise to the above pressure under low ambient temperature conditions, a part of the hot gas is passed to the receiver via the hot gas bypass circuit. By introducing, the intermediate pressure can be controlled to the above pressure. Therefore, the refrigerant filling amount can be accurately detected even under a low outside air temperature condition, and the optimum amount of refrigerant can be filled. In addition, this makes it possible to easily increase the pressure even under a low outside air temperature condition, and can be effectively applied to high pressure control or the like during cooling at a low outside air temperature.
さらに、本発明の第2の態様にかかる空気調和機の冷媒量検出方法は、圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を有する室外機と、室内熱交換器、冷房用膨張弁等を有する室内機とをガス冷媒配管および液冷媒配管で接続し、閉サイクルの冷媒回路を構成している空気調和機の冷媒量検出方法において、冷媒充填運転時、前記レシーバ内の中間圧力を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該中間圧冷媒を前記レシーバの所定高さ位置から前記圧縮機吸入側に接続されている液面検出回路に取出し、該液面検出回路中で低圧状態に減圧された冷媒の温度を検出することにより冷媒充填量を判定する。
Furthermore, the refrigerant amount detection method for an air conditioner according to the second aspect of the present invention includes an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve, a receiver storing liquid refrigerant, and the like, and indoor heat exchange. In the refrigerant amount detection method of the air conditioner that connects the indoor unit having an air conditioner, an expansion valve for cooling, etc. with a gas refrigerant pipe and a liquid refrigerant pipe, and constitutes a closed cycle refrigerant circuit, The intermediate pressure in the receiver is controlled to a pressure at which the superheat degree is at least 5 deg of the saturated gas temperature with a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram rises to the right. From the predetermined height position of the receiver to a liquid level detecting circuit connected to the compressor suction side, and detecting the temperature of the refrigerant decompressed to a low pressure state in the liquid level detecting circuit, Determine.
本発明の第2の態様によれば、冷媒充填運転時、レシーバ内の冷媒の中間圧力を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該中間圧冷媒をレシーバの所定高さ位置から圧縮機吸入側に接続されている液面検出回路に取出し、該液面検出回路中で低圧状態に減圧された冷媒の温度を検出することにより冷媒充填量を判定するようにしているため、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる中間圧力に制御されたレシーバ内から飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧された後の冷媒温度を検出し、その温度差からレシーバ内に所定液面レベルの液冷媒が溜まったことを検出することができる。従って、冷媒の吐出側圧力(高圧)に左右されることなく、また、冷媒を加熱する部を設けることなく、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、空気調和機に過不足のない最適量の冷媒を充填することが可能となる。
According to the second aspect of the present invention, during the refrigerant charging operation, the intermediate pressure of the refrigerant in the receiver is equal to or greater than 5 deg. Of the saturated gas temperature with a superheat degree of low pressure, and the saturated gas line of the pressure-enthalpy diagram. The pressure is controlled so that the slope becomes an upwardly rising region, and the intermediate-pressure refrigerant is taken out from the predetermined height position of the receiver to the liquid level detection circuit connected to the compressor suction side, and the low pressure in the liquid level detection circuit Since the refrigerant charging amount is determined by detecting the temperature of the refrigerant whose pressure has been reduced to the state, the degree of superheat is not less than 5 deg. Of the saturated gas temperature of the low pressure, and the saturated gas line of the pressure-enthalpy diagram The refrigerant temperature after decompression is detected when the saturated gas refrigerant is taken out from the receiver controlled in the intermediate pressure where the inclination is an area where the inclination rises to the right and when the saturated liquid refrigerant is taken out, respectively. The temperature difference It is possible to detect that the accumulated predetermined liquid level of the liquid refrigerant in Luo the receiver. Therefore, the refrigerant filling amount can be detected with high accuracy by ensuring the temperature difference sufficiently without being influenced by the discharge pressure (high pressure) of the refrigerant and without providing a portion for heating the refrigerant. It is possible to fill the air conditioner with an optimal amount of refrigerant without excess or deficiency.
本発明によると、空気調和機および空気調和機の冷媒量検出方法によると、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる中間圧に制御されたレシーバから飽和ガス冷媒が取出された場合と、飽和液冷媒が取出された場合とにおいて、それぞれ減圧後の冷媒温度を検出し、その温度差からレシーバ内に所定液面の液冷媒が溜まったことを検出することが可能となるため、冷媒の吐出側圧力に左右されることなく、また、冷媒加熱部を設けることなく、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。
According to the present invention, according to the air conditioner and the refrigerant amount detection method of the air conditioner, the degree of superheat is not less than 5 deg of the low pressure saturated gas temperature, and the slope of the saturated gas line in the pressure-enthalpy diagram rises to the right. When the saturated gas refrigerant is taken out from the receiver controlled to the intermediate pressure that becomes the region of the above and when the saturated liquid refrigerant is taken out, the refrigerant temperature after depressurization is detected, and the difference in temperature is detected in the receiver. Since it is possible to detect that the liquid refrigerant of a predetermined liquid level has accumulated, the above temperature difference is sufficiently ensured without being influenced by the refrigerant discharge side pressure and without providing a refrigerant heating section. Thus, the refrigerant charge amount can be detected with high accuracy, and the optimum amount of refrigerant can be charged without excess or deficiency, and the air conditioner can be operated stably.
以下に、本発明にかかる実施形態について、図面を参照して説明する。
[第1実施形態]
以下、本発明の第1実施形態について、図1ないし図5を用いて説明する。
図1には、本発明の第1実施形態にかかる空気調和機の冷媒回路図が示されている。
空気調和機1は、ビル等の空調に適用されるマルチタイプの空気調和機であり、室外機2と、互いに並列に接続される複数台の室内機3(図1には、1台だけ図示されている。)とから構成されている。 Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows a refrigerant circuit diagram of an air conditioner according to the first embodiment of the present invention.
The air conditioner 1 is a multi-type air conditioner that is applied to air conditioning of buildings and the like, and includes anoutdoor unit 2 and a plurality of indoor units 3 connected in parallel to each other (FIG. 1 shows only one unit). It is composed of).
[第1実施形態]
以下、本発明の第1実施形態について、図1ないし図5を用いて説明する。
図1には、本発明の第1実施形態にかかる空気調和機の冷媒回路図が示されている。
空気調和機1は、ビル等の空調に適用されるマルチタイプの空気調和機であり、室外機2と、互いに並列に接続される複数台の室内機3(図1には、1台だけ図示されている。)とから構成されている。 Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows a refrigerant circuit diagram of an air conditioner according to the first embodiment of the present invention.
The air conditioner 1 is a multi-type air conditioner that is applied to air conditioning of buildings and the like, and includes an
室外機2の内部には、冷媒を圧縮する圧縮機10、冷媒の循環方向を切換える四方切換弁11、外気と冷媒とを熱交換する室外熱交換器12、室外熱交換器12に外気を通風する室外ファン13、暖房用電動膨張弁(暖房用膨張弁)14、凝縮された液冷媒を溜めるレシーバ15等が配設されており、圧縮機10、四方切換弁11、室外熱交換器12、暖房用電動膨張弁14およびレシーバ15が順次冷媒配管16を介して接続されることによって、室外側冷媒回路17が構成されている。
Inside the outdoor unit 2, a compressor 10 that compresses the refrigerant, a four-way switching valve 11 that switches the circulation direction of the refrigerant, an outdoor heat exchanger 12 that exchanges heat between the outside air and the refrigerant, and the outside air are passed through the outdoor heat exchanger 12. An outdoor fan 13 for heating, an electric expansion valve for heating (heating expansion valve) 14, a receiver 15 for accumulating condensed liquid refrigerant, and the like are disposed, and a compressor 10, a four-way switching valve 11, an outdoor heat exchanger 12, The outdoor refrigerant circuit 17 is configured by sequentially connecting the heating electric expansion valve 14 and the receiver 15 via the refrigerant pipe 16.
室内機3の内部には、室内熱交換器20、室内熱交換器20を通して室内空気を循環させる室内ファン21、冷房用電動膨張弁(冷房用膨張弁)22等が配設されており、この室内機3と室外機2とがガス冷媒配管23および液冷媒配管24を介して接続されることにより、閉サイクルの冷媒回路25が構成されるようになっている。複数台の室内機3は、ガス冷媒配管23および液冷媒配管24から分岐されたガス冷媒配管23および液冷媒配管24を介して互いに並列に接続されるようになっている。
Inside the indoor unit 3, an indoor heat exchanger 20, an indoor fan 21 that circulates indoor air through the indoor heat exchanger 20, a cooling electric expansion valve (cooling expansion valve) 22, and the like are disposed. The indoor unit 3 and the outdoor unit 2 are connected via a gas refrigerant pipe 23 and a liquid refrigerant pipe 24, whereby a closed-cycle refrigerant circuit 25 is configured. The plurality of indoor units 3 are connected in parallel to each other via the gas refrigerant pipe 23 and the liquid refrigerant pipe 24 branched from the gas refrigerant pipe 23 and the liquid refrigerant pipe 24.
空気調和機1は、圧縮機10から吐出された冷媒を、四方切換弁11を介して室外熱交換器12側に循環させ、レシーバ15、冷房用電動膨張弁22、室内熱交換器20、四方切換弁11および圧縮機10の順に時計方向に循環させることによって、室外熱交換器12を凝縮器、室内熱交換器20を蒸発器として機能させ、冷房運転できるようになっている。一方、圧縮機10から吐出された冷媒を、四方切換弁11を介して室内熱交換器20側に循環させ、レシーバ15、暖房用電動膨張弁14、室外熱交換器12、四方切換弁11および圧縮機10の順に反時計方向に循環させることによって、室内熱交換器20を凝縮器、室外熱交換器12を蒸発器として機能させ、暖房運転できるようになっている。
The air conditioner 1 circulates the refrigerant discharged from the compressor 10 to the outdoor heat exchanger 12 side via the four-way switching valve 11, and receives the receiver 15, the cooling electric expansion valve 22, the indoor heat exchanger 20, and the four-way switching valve 11. By circulating the switching valve 11 and the compressor 10 in the clockwise direction, the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 20 functions as an evaporator so that a cooling operation can be performed. On the other hand, the refrigerant discharged from the compressor 10 is circulated to the indoor heat exchanger 20 side via the four-way switching valve 11, and the receiver 15, the heating electric expansion valve 14, the outdoor heat exchanger 12, the four-way switching valve 11, and By circulating counterclockwise in the order of the compressor 10, the indoor heat exchanger 20 functions as a condenser and the outdoor heat exchanger 12 functions as an evaporator so that heating operation can be performed.
上記空気調和機1において、室外機2と室内機3との間を接続するガス冷媒配管23および液冷媒配管24の配管長さは、空気調和機1が据付けられる環境によって様々変化する。このため、予め室外機2に所定量の冷媒を充填しておき、現地において空気調和機1を据付けした後、試運転するときに、室外機2と室内機3との間を接続する配管長さや室内機3の接続台数等に応じて不足量の冷媒を追加充填しなければならない。この冷媒を追加充填する際、現地での工事レベルに依存することなく、常に適正な量の冷媒を充填できるようにするため、以下の液面検出回路30および冷媒量検出部35が組み込まれている。
In the air conditioner 1, the lengths of the gas refrigerant pipe 23 and the liquid refrigerant pipe 24 that connect the outdoor unit 2 and the indoor unit 3 vary depending on the environment in which the air conditioner 1 is installed. For this reason, when the outdoor unit 2 is preliminarily filled with a predetermined amount of refrigerant and the air conditioner 1 is installed in the field, the length of the pipe connecting the outdoor unit 2 and the indoor unit 3 when the test operation is performed Insufficient amount of refrigerant must be charged according to the number of indoor units 3 connected. When the refrigerant is additionally charged, the following liquid level detection circuit 30 and the refrigerant amount detection unit 35 are incorporated in order to always be able to charge an appropriate amount of refrigerant without depending on the construction level at the site. Yes.
液面検出回路30は、レシーバ15内の所定高さ位置から圧縮機10の吸入側に冷媒を取出すことができるバイパス回路31と、このバイパス回路31中に設けられているキャピラリチューブ、膨張弁等からなる減圧機構32および電磁開閉弁33と、このバイパス回路31に取出され、減圧機構32によって減圧された後の冷媒温度を検出するサーミスタ等の温度センサ(温度検出部)34とを備えている。
The liquid level detection circuit 30 includes a bypass circuit 31 that can take out the refrigerant from a predetermined height position in the receiver 15 to the suction side of the compressor 10, and a capillary tube, an expansion valve, and the like provided in the bypass circuit 31. And a temperature sensor (temperature detection unit) 34 such as a thermistor for detecting the refrigerant temperature after being taken out by the bypass circuit 31 and decompressed by the decompression mechanism 32. .
冷媒量検出部35は、温度センサ34の検出温度に基づいて適正量の冷媒が充填されたか否かを判定するためのものであり、冷媒充填運転中に、レシーバ15内に液冷媒が溜まり、その液面レベルが、バイパス回路31が開口する高さ位置に到達し、バイパス回路31に飽和状態の液冷媒が取出された場合における温度センサ34からの検出温度と、液冷媒が所定高さ位置に到達するまで間、レシーバ15からバイパス回路31に飽和状態のガス冷媒が取出されていた場合における温度センサ34からの検出温度との温度差に基づいて、適正量の冷媒が充填されたか否かを判定できる構成とされている。
The refrigerant amount detection unit 35 is for determining whether or not an appropriate amount of refrigerant is filled based on the temperature detected by the temperature sensor 34. During the refrigerant filling operation, the liquid refrigerant is accumulated in the receiver 15, The liquid level reaches the height position at which the bypass circuit 31 is opened, and the detected temperature from the temperature sensor 34 when the saturated liquid refrigerant is taken out to the bypass circuit 31 and the liquid refrigerant at a predetermined height position. Whether or not an appropriate amount of refrigerant has been charged based on the temperature difference from the temperature detected by the temperature sensor 34 when the saturated gas refrigerant is taken out from the receiver 15 to the bypass circuit 31 from the receiver 15. Can be determined.
さらに、冷媒量検出部35は、冷媒充填運転時、レシーバ15内の中間圧を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御する機能を担っている。これは、例えば中間圧センサ36によって検出された中間圧が圧力-エンタルピ線図上において、過熱度が低圧の飽和ガス温度の5deg以上であって、飽和ガス線の傾きが右肩上がりの領域となる圧力となるように、圧縮機10の回転数、室外ファン13の回転数、あるいは暖房用電動膨張弁14の開度を調整することによって制御するものである。
Further, during the refrigerant charging operation, the refrigerant amount detection unit 35 sets the intermediate pressure in the receiver 15 to 5 degrees or more of the saturated gas temperature at which the superheat is low, and the slope of the saturated gas line in the pressure-enthalpy diagram is on the right. It has a function to control the pressure to become a shoulder rise area. This is because, for example, the intermediate pressure detected by the intermediate pressure sensor 36 is not less than 5 deg. Of the saturated gas temperature of the low pressure on the pressure-enthalpy diagram, and the slope of the saturated gas line rises to the right. The pressure is controlled by adjusting the rotational speed of the compressor 10, the rotational speed of the outdoor fan 13, or the opening degree of the heating electric expansion valve 14 so that the pressure becomes the same pressure.
レシーバ15内の中間圧力は、中間圧センサ36に代えて、図2に示されるように、バイパス回路31の冷媒取出し部に設けられた温度センサ37からの検出温度を冷媒の飽和ガス温度として圧力に換算して検出するようにしてもよいし、あるいは図3に示されるように、圧縮機10の吐出配管に設けられている高圧センサ38と室外熱交換器12の出口に設けられている冷媒の過冷却度を検出する温度センサ39からの検出値に基づいて、エンタルピ一定の飽和液圧力に換算して算出するようにしてもよい。
As shown in FIG. 2, the intermediate pressure in the receiver 15 is a pressure obtained by using the detected temperature from the temperature sensor 37 provided in the refrigerant take-out portion of the bypass circuit 31 as the saturated gas temperature of the refrigerant, as shown in FIG. 2. Or the refrigerant provided at the outlet of the high-pressure sensor 38 and the outdoor heat exchanger 12 provided in the discharge pipe of the compressor 10 as shown in FIG. On the basis of the detected value from the temperature sensor 39 that detects the degree of supercooling, the enthalpy may be converted into a saturated liquid pressure that is constant.
次に、冷媒充填運転と冷媒充填量の検出方法について、図4および図5を参照して更に詳しく説明する。
冷媒充填運転は、冷媒回路25を冷房サイクルとして運転される。この際、室外熱交換器12での凝縮圧力が所定値となるように室外ファン13が制御されるとともに、室内熱交換器20の出口で冷媒に所定の過熱度が付与されるように冷房用電動膨張弁22の開度が制御される。これにより、液冷媒配管24内に所定密度の液冷媒を満たした状態として冷媒回路25に冷媒を充填することができる。このとき、液面検出回路30の電磁開閉弁33は開状態とされている。 Next, the refrigerant filling operation and the refrigerant filling amount detection method will be described in more detail with reference to FIG. 4 and FIG.
In the refrigerant charging operation, therefrigerant circuit 25 is operated as a cooling cycle. At this time, the outdoor fan 13 is controlled so that the condensation pressure in the outdoor heat exchanger 12 becomes a predetermined value, and at the outlet of the indoor heat exchanger 20, a predetermined superheat degree is given to the refrigerant. The opening degree of the electric expansion valve 22 is controlled. Thereby, the refrigerant can be filled in the refrigerant circuit 25 in a state where the liquid refrigerant pipe 24 is filled with the liquid refrigerant having a predetermined density. At this time, the electromagnetic opening / closing valve 33 of the liquid level detection circuit 30 is open.
冷媒充填運転は、冷媒回路25を冷房サイクルとして運転される。この際、室外熱交換器12での凝縮圧力が所定値となるように室外ファン13が制御されるとともに、室内熱交換器20の出口で冷媒に所定の過熱度が付与されるように冷房用電動膨張弁22の開度が制御される。これにより、液冷媒配管24内に所定密度の液冷媒を満たした状態として冷媒回路25に冷媒を充填することができる。このとき、液面検出回路30の電磁開閉弁33は開状態とされている。 Next, the refrigerant filling operation and the refrigerant filling amount detection method will be described in more detail with reference to FIG. 4 and FIG.
In the refrigerant charging operation, the
この状態で運転を継続すると、冷媒回路25中の冷媒循環量が徐々に増大され、レシーバ15内の冷媒の液面が徐々に上昇してくる。これは、室内熱交換器20での冷媒の蒸発量と室外熱交換器12での冷媒の凝縮量がバランスしているためであり、レシーバ15内には外部から充填される冷媒量の分だけ、液冷媒が徐々に溜まってくる。この際、液面検出回路30のバイパス回路31が開口されている高さ位置まで、レシーバ15内に液冷媒が溜まるまでの間は、レシーバ15内の飽和状態のガス冷媒がバイパス回路31に流れることになり、バイパス回路31が開口されている高さ位置まで液冷媒の液面レベルが上昇すると、飽和状態の液冷媒がバイパス回路31に流れることになる。
If the operation is continued in this state, the refrigerant circulation amount in the refrigerant circuit 25 is gradually increased, and the liquid level of the refrigerant in the receiver 15 gradually rises. This is because the amount of refrigerant evaporated in the indoor heat exchanger 20 and the amount of refrigerant condensed in the outdoor heat exchanger 12 are balanced, and the receiver 15 is filled with the amount of refrigerant charged from the outside. Liquid refrigerant gradually accumulates. At this time, the saturated gas refrigerant in the receiver 15 flows to the bypass circuit 31 until the liquid refrigerant is accumulated in the receiver 15 up to a height position where the bypass circuit 31 of the liquid level detection circuit 30 is opened. That is, when the liquid level of the liquid refrigerant rises to the height position where the bypass circuit 31 is opened, the saturated liquid refrigerant flows into the bypass circuit 31.
この飽和ガス冷媒または飽和液冷媒は、それぞれ減圧機構33によって低圧状態に減圧され、温度降下する。この冷媒の温度を温度センサ34で検出することにより、飽和ガス冷媒の状態から温度降下した場合と、飽和液冷媒の状態から温度降下した場合との温度差を見て、冷媒量検出部35がレシーバ15内に所定液面の液冷媒が溜まったことを検出し、所要量の冷媒が充填されたと判定するようにしており、この時点で冷媒の充填運転が終了されることになる。
The saturated gas refrigerant or saturated liquid refrigerant is decompressed to a low pressure state by the decompression mechanism 33, and the temperature drops. By detecting the temperature of the refrigerant with the temperature sensor 34, the refrigerant amount detection unit 35 looks at the temperature difference between the temperature drop from the saturated gas refrigerant state and the temperature drop from the saturated liquid refrigerant state. It is determined that the liquid refrigerant of a predetermined liquid level has accumulated in the receiver 15, and it is determined that the required amount of refrigerant has been filled. At this point, the refrigerant filling operation is terminated.
ここで、適正量の冷媒が充填されたことを精度よく検出するためには、上記温度差が十分に確保されることが望ましい。通常、バイパス回路31に流れ込んだ飽和液冷媒は、減圧機構33により減圧されて気液二相状態となり蒸発するため、温度センサ34による検出温度は急激に低下する。これに対して、飽和ガス状態で流れ込んだ冷媒は、例えば外気温の上昇により圧縮機10の吐出側圧力が高くなって、圧力-エンタルピ線図の飽和ガス線の傾きが左肩上がりとなる条圧力件下では、減圧機構33で減圧されたとき、気液二相状態となるケースがあり、この場合、冷媒の蒸発による急激な温度降下を検出してしまうことになり、冷媒量検出部35が、液冷媒が所定液面レベルに到達していると誤判定してしまうおそれがある。
Here, in order to accurately detect that an appropriate amount of refrigerant has been charged, it is desirable that the temperature difference is sufficiently secured. Normally, the saturated liquid refrigerant that has flowed into the bypass circuit 31 is decompressed by the decompression mechanism 33 to become a gas-liquid two-phase state and evaporates, so that the temperature detected by the temperature sensor 34 rapidly decreases. On the other hand, the refrigerant flowing in the saturated gas state increases the discharge-side pressure of the compressor 10 due to, for example, an increase in the outside air temperature, and the strip pressure in which the slope of the saturated gas line in the pressure-enthalpy diagram increases to the left. Under the circumstances, there is a case where a gas-liquid two-phase state occurs when the pressure is reduced by the pressure reducing mechanism 33. In this case, a rapid temperature drop due to the evaporation of the refrigerant is detected, and the refrigerant amount detecting unit 35 is The liquid refrigerant may erroneously be determined to have reached a predetermined liquid level.
しかるに、本実施形態では、レシーバ15内における冷媒の中間圧力を、図4に示されるように、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図上の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、この状態の飽和ガス冷媒をバイパス回路31に取出し、それを減圧させて温度降下させるようにしているため、低圧に減圧された冷媒の飽和ガス温度に対して、常に5deg以上の過熱度SHを確保することが可能となる。
However, in this embodiment, as shown in FIG. 4, the intermediate pressure of the refrigerant in the receiver 15 is not less than 5 deg. Of the saturated gas temperature of the low pressure, and the saturated gas line on the pressure-enthalpy diagram. Since the saturated gas refrigerant in this state is taken out to the bypass circuit 31 and is depressurized to lower the temperature, the saturation of the refrigerant depressurized to low pressure is controlled. It is possible to always secure a superheat degree SH of 5 deg or more with respect to the gas temperature.
つまり、図4中において、飽和液冷媒から減圧されて温度降下したA点に対して、飽和ガス状態から減圧されて温度降下した場合、減圧により気液二相状態となるようなケースでは、ほぼ飽和ガス線上に温度降下し、過熱度が大きい場合でも2~3℃にしかならないことがあり、この場合、温度差を十分に確保することができず誤判定の要因となる。しかし、本実施形態の場合、常に、少なくとも5deg以上の過熱度SHを確保できるB点に温度降下させることができるため、誤判定を確実に解消することができる。
That is, in FIG. 4, when the temperature is reduced from the saturated gas state to the point A where the temperature is reduced due to the reduced pressure from the saturated liquid refrigerant, in the case where the gas-liquid two-phase state is brought about by the reduced pressure, Even when the temperature drops on the saturated gas line and the degree of superheat is large, the temperature may reach only 2 to 3 ° C. In this case, a sufficient temperature difference cannot be ensured, resulting in erroneous determination. However, in the case of this embodiment, the temperature can always be lowered to the point B at which the degree of superheating SH of at least 5 deg or more can be secured, so that erroneous determination can be reliably eliminated.
図4は、レシーバ15内の圧力を飽和ガス線でエンタルピ最大付近とした場合の圧力-エンタルピ線図であり、R410A冷媒を使用し、2MPa付近からバイパス回路31に冷媒を取出し、温度降下させた場合のものであるが、実際の冷媒充填運転時の圧力-エンタルピ線図は、図5に示すようになる。つまり、圧縮機10の吐出側圧力は、レシーバ15内の中間圧よりも高いが、この高圧に左右されることなく、レシーバ15内の中間圧を、中間圧センサ36、バイパス回路31に流れ込む冷媒温度を検出する温度センサ37、あるいは高圧センサ38および室外熱交換器13出口の冷媒過冷却度を検出する温度センサ39等からの検出値またはその換算値から中間圧力を検出し、圧縮機10の回転数、室外熱交換器12に外気を通風する室外ファン13の回転数、または暖房用膨張弁14の開度等を制御して上記圧力に制御することにより、レシーバ15内の液冷媒は、飽和液線上となる。
FIG. 4 is a pressure-enthalpy diagram when the pressure in the receiver 15 is set to the vicinity of the maximum enthalpy with a saturated gas line. Using R410A refrigerant, the refrigerant is taken out from the vicinity of 2 MPa to the bypass circuit 31 and the temperature is lowered. Although it is a case, the pressure-enthalpy diagram at the time of the actual refrigerant filling operation is as shown in FIG. That is, although the discharge side pressure of the compressor 10 is higher than the intermediate pressure in the receiver 15, the intermediate pressure in the receiver 15 flows into the intermediate pressure sensor 36 and the bypass circuit 31 without being influenced by this high pressure. The intermediate pressure is detected from the detected value from the temperature sensor 37 for detecting the temperature, the temperature sensor 39 for detecting the degree of refrigerant supercooling at the outlet of the high pressure sensor 38 and the outdoor heat exchanger 13 or the converted value thereof. By controlling the rotational speed, the rotational speed of the outdoor fan 13 that ventilates the outdoor air to the outdoor heat exchanger 12, or the opening degree of the heating expansion valve 14, etc., the liquid refrigerant in the receiver 15 is controlled by the above pressure. It is on the saturated liquid line.
このレシーバ15から飽和ガス冷媒または飽和液冷媒をバイパス回路31に取出し、それを減圧機構33により減圧して温度降下させ、それぞれ温度を温度センサ34で検出することによって、その温度差から冷媒量検出部35を介して冷媒量を精度よく検出することができる。
従って、本実施形態によると、外気温等に影響される冷媒の吐出側圧力(高圧)に左右されることなく、また、バイパス回路31に冷媒加熱部を設けることなく、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。 The saturated gas refrigerant or the saturated liquid refrigerant is taken out from thereceiver 15 to the bypass circuit 31 and is decompressed by the decompression mechanism 33 to decrease the temperature, and the temperature is detected by the temperature sensor 34 to detect the refrigerant amount from the temperature difference. The amount of refrigerant can be accurately detected via the unit 35.
Therefore, according to the present embodiment, the temperature difference is sufficiently reduced without being influenced by the discharge side pressure (high pressure) of the refrigerant that is influenced by the outside air temperature or the like and without providing the refrigerant heating unit in thebypass circuit 31. It is possible to secure and detect the refrigerant filling amount with high accuracy, and to fill the optimum amount of refrigerant without excess and deficiency and to operate the air conditioner stably.
従って、本実施形態によると、外気温等に影響される冷媒の吐出側圧力(高圧)に左右されることなく、また、バイパス回路31に冷媒加熱部を設けることなく、上記温度差を十分に確保して高精度で冷媒充填量を検出することができ、過不足のない最適量の冷媒を充填し、空気調和機を安定して運転することが可能となる。 The saturated gas refrigerant or the saturated liquid refrigerant is taken out from the
Therefore, according to the present embodiment, the temperature difference is sufficiently reduced without being influenced by the discharge side pressure (high pressure) of the refrigerant that is influenced by the outside air temperature or the like and without providing the refrigerant heating unit in the
[第2実施形態]
次に、本発明の第2実施形態について、図6を用いて説明する。
本実施形態は、上記した第1実施形態に対して、ホットガスバイパス回路40が付加されている点が異なっている。その他の点については、第1実施形態と同様であるので説明は省略する。
本実施形態では、図6に示されるように、圧縮機10からの吐出配管とレシーバ15との間に、圧縮機10から吐出されたホットガスの一部をレシーバ15内に導入することができるホットガスバイパス回路40を設けた構成としている。このホットガスバイパス回路40には、電磁開閉弁41とキャピラリチューブや膨張弁等の減圧機構42とが介装されている。 [Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment is different from the first embodiment described above in that a hotgas bypass circuit 40 is added. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, as shown in FIG. 6, a part of the hot gas discharged from thecompressor 10 can be introduced into the receiver 15 between the discharge pipe from the compressor 10 and the receiver 15. The hot gas bypass circuit 40 is provided. The hot gas bypass circuit 40 is provided with an electromagnetic opening / closing valve 41 and a pressure reducing mechanism 42 such as a capillary tube or an expansion valve.
次に、本発明の第2実施形態について、図6を用いて説明する。
本実施形態は、上記した第1実施形態に対して、ホットガスバイパス回路40が付加されている点が異なっている。その他の点については、第1実施形態と同様であるので説明は省略する。
本実施形態では、図6に示されるように、圧縮機10からの吐出配管とレシーバ15との間に、圧縮機10から吐出されたホットガスの一部をレシーバ15内に導入することができるホットガスバイパス回路40を設けた構成としている。このホットガスバイパス回路40には、電磁開閉弁41とキャピラリチューブや膨張弁等の減圧機構42とが介装されている。 [Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment is different from the first embodiment described above in that a hot
In the present embodiment, as shown in FIG. 6, a part of the hot gas discharged from the
このように、圧縮機10の吐出側とレシーバ15との間に、電磁開閉弁41および減圧機構42が介装されたホットガスバイパス回路40を設け、レシーバ15内に圧縮機10から吐出されたホットガスの一部を導入可能とすることにより、例えば低外気温条件下であって、冷媒充填運転時に、レシーバ15内の中間圧が上述した圧力まで上昇しないような場合でも、電磁開閉弁41を開とし、ホットガスバイパス回路40を介してホットガスをレシーバ15に導入することによって、レシーバ15内の中間圧を上述の圧力に制御することができる。
As described above, the hot gas bypass circuit 40 in which the electromagnetic on-off valve 41 and the pressure reducing mechanism 42 are interposed is provided between the discharge side of the compressor 10 and the receiver 15, and is discharged from the compressor 10 into the receiver 15. By allowing a part of the hot gas to be introduced, the electromagnetic on-off valve 41 can be used even when the intermediate pressure in the receiver 15 does not rise to the above-described pressure during the refrigerant charging operation, for example, under a low outside air temperature condition. Is opened, and hot gas is introduced into the receiver 15 via the hot gas bypass circuit 40, whereby the intermediate pressure in the receiver 15 can be controlled to the above-described pressure.
従って、低外気温条件下であっても、精度よく冷媒充填量を検出することができ、最適量の冷媒を充填することができる。また、これによって、低外気温条件下でも容易に圧力を上昇させることが可能となる。一般に、圧力を下げる側の制御は容易であり、圧力を上げる側の制御は難しいが、本実施形態により、低外気温時の圧力制御を容易化することができる。さらに、このホットガスバイパス回路40は、冷媒充填運転時に限らず、低外気温冷房時の高圧制御等にも有効に適用することができ、空気調和機1による冷房運転範囲の拡大にも資することができる。
Therefore, even under a low outside air temperature condition, the refrigerant charging amount can be detected with high accuracy, and the optimal amount of refrigerant can be charged. This also makes it possible to easily increase the pressure even under low outside air temperature conditions. In general, the control for reducing the pressure is easy and the control for increasing the pressure is difficult. However, according to the present embodiment, the pressure control at the low outside air temperature can be facilitated. Furthermore, the hot gas bypass circuit 40 can be effectively applied not only to the refrigerant charging operation but also to high pressure control at the time of cooling at a low outside air temperature, and contributes to the expansion of the cooling operation range by the air conditioner 1. Can do.
本発明は、上記実施形態にかかる発明に限定されるものではなく、その要旨を逸脱しない範囲において、適宜変形が可能である。例えば、上記実施形態では、レシーバ15に対して液面検出回路30のバイパス回路31がレシーバ15の上面から挿入接続された構成とされているが、バイパス回路31は、レシーバ15内の所定高さ位置に開口されるように接続されておればよく、従って、レシーバ15の側面あるいは下面から挿入して所定高さ位置に開口されるように接続してもよい。
The present invention is not limited to the invention according to the above-described embodiment, and can be modified as appropriate without departing from the scope of the invention. For example, in the above embodiment, the bypass circuit 31 of the liquid level detection circuit 30 is inserted and connected to the receiver 15 from the upper surface of the receiver 15, but the bypass circuit 31 has a predetermined height in the receiver 15. It is only necessary to be connected so as to be opened at a position, and therefore, it may be inserted so as to be opened from a side surface or a lower surface of the receiver 15 so as to be opened at a predetermined height position.
1 空気調和機
2 室外機
3 室内機
10 圧縮機
12 室外熱交換器
13 室外ファン
14 暖房用電動膨張弁(暖房用膨張弁)
15 レシーバ
20 室内熱交換器
22 冷房用電動膨張弁(冷房用膨張弁)
23 ガス冷媒配管
24 液冷媒配管
25 冷媒回路
30 液面検出回路
31 バイパス回路
32 減圧機構
33 電磁開閉弁
34 温度センサ(温度検出部)
35 冷媒量検出部
36 中間圧センサ
37 温度センサ
38 高圧センサ
39 温度センサ
40 ホットガスバイパス回路 DESCRIPTION OF SYMBOLS 1Air conditioner 2 Outdoor unit 3 Indoor unit 10 Compressor 12 Outdoor heat exchanger 13 Outdoor fan 14 Electric expansion valve for heating (expansion valve for heating)
15Receiver 20 Indoor Heat Exchanger 22 Electric Expansion Valve for Cooling (Expansion Valve for Cooling)
23Gas refrigerant pipe 24 Liquid refrigerant pipe 25 Refrigerant circuit 30 Liquid level detection circuit 31 Bypass circuit 32 Pressure reducing mechanism 33 Electromagnetic on-off valve 34 Temperature sensor (temperature detection unit)
35 Refrigerantamount detection unit 36 Intermediate pressure sensor 37 Temperature sensor 38 High pressure sensor 39 Temperature sensor 40 Hot gas bypass circuit
2 室外機
3 室内機
10 圧縮機
12 室外熱交換器
13 室外ファン
14 暖房用電動膨張弁(暖房用膨張弁)
15 レシーバ
20 室内熱交換器
22 冷房用電動膨張弁(冷房用膨張弁)
23 ガス冷媒配管
24 液冷媒配管
25 冷媒回路
30 液面検出回路
31 バイパス回路
32 減圧機構
33 電磁開閉弁
34 温度センサ(温度検出部)
35 冷媒量検出部
36 中間圧センサ
37 温度センサ
38 高圧センサ
39 温度センサ
40 ホットガスバイパス回路 DESCRIPTION OF SYMBOLS 1
15
23
35 Refrigerant
Claims (4)
- 圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を有する室外機と、室内熱交換器、冷房用膨張弁等を有する室内機とをガス冷媒配管および液冷媒配管により接続し、閉サイクルの冷媒回路を構成している空気調和機において、
前記レシーバの所定高さ位置と前記圧縮機の吸入側との間を接続するバイパス回路に開閉弁および減圧機構を設けた液面検出回路と、
前記液面検出回路を流れる前記減圧機構によって減圧された冷媒の温度を検出する温度検出部と、
前記レシーバ内の中間圧を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、該レシーバから前記液面検出回路に取出された冷媒の温度を前記温度検出部で検出することにより、該温度に基づいて冷媒充填量を判定する冷媒量検出部と、を備えている空気調和機。 An outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve and a receiver for storing liquid refrigerant, and an indoor unit having an indoor heat exchanger, a cooling expansion valve, and the like are connected by gas refrigerant pipe and liquid refrigerant pipe. In an air conditioner that connects and configures a closed-cycle refrigerant circuit,
A liquid level detection circuit provided with an on-off valve and a pressure reducing mechanism in a bypass circuit connecting between a predetermined height position of the receiver and the suction side of the compressor;
A temperature detector that detects the temperature of the refrigerant decompressed by the decompression mechanism flowing through the liquid level detection circuit;
The intermediate pressure in the receiver is controlled to a pressure at which the superheat degree is 5 deg or more of the saturated gas temperature at a low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is in a region that rises to the right. An air conditioner comprising: a refrigerant amount detection unit that determines a refrigerant filling amount based on the temperature detected by the temperature detection unit by detecting the temperature of the refrigerant taken out by the liquid level detection circuit. - 前記冷媒量検出部は、中間圧センサ、前記液面検出回路に取出された冷媒温度を検出する温度センサ、あるいは高圧センサおよび前記室外熱交換器出口の冷媒過冷却度を検出する温度センサ等からの検出値またはその換算値から前記中間圧を検出し、前記圧縮機の回転数、前記室外熱交換器に外気を通風する室外ファンの回転数、または前記暖房用膨張弁の開度等を制御して、前記レシーバ内の中間圧を前記圧力に制御するように構成されている請求項1に記載の空気調和機。 The refrigerant amount detection unit includes an intermediate pressure sensor, a temperature sensor that detects a refrigerant temperature taken out by the liquid level detection circuit, a high-pressure sensor, a temperature sensor that detects a refrigerant subcooling degree at the outlet of the outdoor heat exchanger, and the like. The intermediate pressure is detected from the detected value or its converted value, and the rotational speed of the compressor, the rotational speed of the outdoor fan that ventilates the outdoor air to the outdoor heat exchanger, or the opening degree of the heating expansion valve is controlled. And the air conditioner of Claim 1 comprised so that the intermediate pressure in the said receiver may be controlled to the said pressure.
- 前記圧縮機の吐出側と前記レシーバとの間に、前記圧縮機から吐出されたホットガスを導入して前記レシーバ内の中間圧を前記圧力に上昇させるためのホットガスバイパス回路が設けられている請求項1または2に記載の空気調和機。 A hot gas bypass circuit is provided between the discharge side of the compressor and the receiver to introduce hot gas discharged from the compressor and raise the intermediate pressure in the receiver to the pressure. The air conditioner according to claim 1 or 2.
- 圧縮機、室外熱交換器、暖房用膨張弁および液冷媒を貯留するレシーバ等を有する室外機と、室内熱交換器、冷房用膨張弁等を有する室内機とをガス冷媒配管および液冷媒配管で接続し、閉サイクルの冷媒回路を構成している空気調和機の冷媒量検出方法において、
冷媒充填運転時、前記レシーバ内の中間圧力を、過熱度が低圧の飽和ガス温度の5deg以上であって、圧力-エンタルピ線図の飽和ガス線の傾きが右肩上がりの領域となる圧力に制御し、
該中間圧冷媒を前記レシーバの所定高さ位置から前記圧縮機吸入側に接続されている液面検出回路に取出し、
該液面検出回路中で低圧状態に減圧された冷媒の温度を検出することにより冷媒充填量を判定する空気調和機の冷媒量検出方法。 A gas refrigerant pipe and a liquid refrigerant pipe connect an outdoor unit having a compressor, an outdoor heat exchanger, a heating expansion valve and a receiver for storing liquid refrigerant, and an indoor unit having an indoor heat exchanger, a cooling expansion valve, etc. In the refrigerant amount detection method of the air conditioner that connects and configures the closed-cycle refrigerant circuit,
During refrigerant charging operation, the intermediate pressure in the receiver is controlled to a pressure where the superheat degree is 5 deg or more of the saturated gas temperature with low pressure, and the slope of the saturated gas line in the pressure-enthalpy diagram is in an upwardly rising area. And
The intermediate pressure refrigerant is taken out from a predetermined height position of the receiver to a liquid level detection circuit connected to the compressor suction side,
A refrigerant amount detection method for an air conditioner that determines a refrigerant charge amount by detecting a temperature of a refrigerant that has been decompressed to a low pressure state in the liquid level detection circuit.
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CN201080030950.9A CN102472538B (en) | 2009-12-10 | 2010-11-25 | Air conditioner and method for detecting amount of refrigerant in air conditioner |
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JP6105256B2 (en) * | 2012-10-31 | 2017-03-29 | 株式会社日本クライメイトシステムズ | Air conditioner for vehicles |
EP3201539B1 (en) | 2014-10-01 | 2021-10-20 | Danfoss A/S | A method, a controller and a system for estimating loss of refrigerant charge in an rvcs system |
WO2016208268A1 (en) * | 2015-06-24 | 2016-12-29 | 株式会社デンソー | Refrigeration cycle apparatus |
CN109869941B (en) * | 2018-12-17 | 2020-03-10 | 珠海格力电器股份有限公司 | Heat pump system, air suction superheat degree and vapor-liquid separator accumulated liquid evaporation control method |
JP7282157B2 (en) * | 2019-03-19 | 2023-05-26 | 三菱電機株式会社 | Outdoor unit and refrigeration cycle device provided with the same |
CN109899940A (en) * | 2019-03-21 | 2019-06-18 | 珠海格力电器股份有限公司 | Air conditioning system and refrigerant quantity control method thereof |
CN114450571A (en) * | 2019-10-04 | 2022-05-06 | 三菱电机株式会社 | Airtightness evaluation device |
JP7489817B2 (en) | 2020-04-17 | 2024-05-24 | 東芝ライフスタイル株式会社 | Air conditioners |
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- 2010-11-25 WO PCT/JP2010/071064 patent/WO2011070917A1/en active Application Filing
- 2010-11-25 CN CN201080030950.9A patent/CN102472538B/en not_active Expired - Fee Related
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Also Published As
Publication number | Publication date |
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CN102472538A (en) | 2012-05-23 |
CN102472538B (en) | 2014-07-23 |
JP2011122766A (en) | 2011-06-23 |
EP2511629A4 (en) | 2017-09-13 |
EP2511629A1 (en) | 2012-10-17 |
JP5595025B2 (en) | 2014-09-24 |
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