US20060000224A1 - Air conditioner - Google Patents

Air conditioner Download PDF

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Publication number
US20060000224A1
US20060000224A1 US10/523,780 US52378005A US2006000224A1 US 20060000224 A1 US20060000224 A1 US 20060000224A1 US 52378005 A US52378005 A US 52378005A US 2006000224 A1 US2006000224 A1 US 2006000224A1
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Prior art keywords
refrigerant
pressure
pressure unit
air conditioner
compressor
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US10/523,780
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English (en)
Inventor
Hiromune Matsuoka
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Daikin Industries Ltd
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Daikin Industries Ltd
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Assigned to DAIKIN INDUSTRIES, LTD. reassignment DAIKIN INDUSTRIES, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MATSUOKA, HIROMUNE
Publication of US20060000224A1 publication Critical patent/US20060000224A1/en
Abandoned legal-status Critical Current

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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
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • 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
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
    • F25B2313/0233—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in parallel arrangements
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
    • F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0313—Pressure sensors near the outdoor heat exchanger
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0314—Temperature sensors near the indoor heat exchanger
    • 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
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/031—Sensor arrangements
    • F25B2313/0315—Temperature sensors near the outdoor heat exchanger
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/01—Geometry problems, e.g. for reducing size
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/21—Reduction of parts
    • 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
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves

Definitions

  • the present invention relates to an air conditioner, and more particularly relates to an air conditioner comprising a plurality of utilization units.
  • the operating load fluctuates greatly, and attendant therewith the amount of refrigerant circulating in a refrigerant circuit fluctuates, thereby causing a fluctuation in the surplus refrigerant inside the refrigerant circuit.
  • This surplus refrigerant is sometimes pooled as a liquid refrigerant in an accumulator connected on the inlet side of a compressor.
  • R407C is a non-azeotropic refrigerant
  • making the surplus refrigerant pool in the accumulator unfortunately causes a compositional change in the refrigerant during the evaporation process in the refrigerating cycle process, i.e., during the refrigerant evaporation process (during cooling operation) in a utilization side heat exchanger of a utilization unit, and during the refrigerant evaporation process (during heating operation) in a heat source side heat exchanger of a heat source unit, resulting in a rich state of the low boiling point component R32 in the gas phase inside the accumulator, and a rich state of the high boiling point component R134a in the liquid phase inside the accumulator. Consequently, the R32-rich refrigerant is sucked into the compressor and circulates inside the refrigerant circuit, and there is a risk that the overall air conditioner will not achieve the performance expected of R407C.
  • Patent Document 1
  • Patent Document 2
  • Patent Document 5
  • a receiver is connected to the refrigerant pipe, wherein a high-pressure liquid refrigerant flows, instead of the accumulator as in the air conditioner that uses the latter R407C mentioned above, then it is preferable in that the constitution as well as operation and control of the refrigerant circuit are not as complicated as the former.
  • the maximum value of the working pressure of the refrigerant flowing inside the refrigerant circuit is higher than the case wherein R407C is used (in contrast with the standard working pressure, a high pressure of approximately 1 MPa is often used, and shall be the maximum working pressure hereinbelow); consequently, the compressive strength of the parts constituting the refrigerant circuit must be increased.
  • the size of the parts that constitute the refrigerant circuit in an air conditioner of a building and the like is larger than a relatively compact air conditioner like a room air conditioner, if the maximum working pressure of the refrigerant circuit portion wherein a high-pressure refrigerant flows (hereinbelow, referred to as the high pressure unit) increases, then the compressive strength of the parts that constitute the refrigerant circuit must consequently be increased, which strongly tends to increase cost. Consequently, to increase the compressive strength of the receiver in an air conditioner comprising a receiver that is one of the parts constituting the abovementioned high pressure unit, the wall thickness must be increased, which increases the cost.
  • the high pressure unit the maximum working pressure of the refrigerant circuit portion wherein a high-pressure refrigerant flows
  • the air conditioner according to the first invention is an air conditioner comprising a plurality of utilization units, comprising a vapor compression type refrigerant circuit and an accumulator.
  • the refrigerant circuit comprises a high pressure unit constituted by the connection of parts capable of flowing a high-pressure refrigerant at a maximum working pressure of 3.3 MPa or higher; and a low pressure unit constituted by the connection of parts capable of flowing only a low-pressure refrigerant at a maximum working pressure of less than 3.3 MPa.
  • the accumulator is one of the parts constituting the low pressure unit and is capable of pooling refrigerant that circulates inside the refrigerant circuit as a liquid refrigerant.
  • the refrigerant that flows through the low pressure unit and the high pressure unit is a pseudo azeotropic refrigerant, an azeotropic refrigerant, or a single refrigerant.
  • the standard working pressure of the high pressure unit is approximately 2.0 MPa. Consequently, if R407C is used as the working refrigerant, then it is often the case in an air conditioner that the maximum working pressure of the high pressure unit is set to 3.0-3.3 MPa, which is a pressure approximately 1 MPa higher than the standard working pressure of 2.0 MPa. Consequently, in the air conditioner that uses R407C as the working refrigerant, it is preferable that the parts constituting the high pressure unit have a compressive strength that can withstand 3.3 MPa.
  • the parts constituting the high pressure unit must have a compressive strength that can withstand a pressure of 3.3 MPa or higher because the maximum working pressure of the high pressure unit exceeds 3.3 MPa.
  • a raw material of the thick wall that satisfies the maximum working pressure condition is normally selected and fabricated from among standard products, such as JIS standard products. Consequently, by using a refrigerant having saturation pressure characteristics higher than R407C, the wall thickness unfortunately increases substantially, and the cost of the parts constituting the refrigerant circuit unfortunately increase unnecessarily.
  • a pseudo azeotropic refrigerant, an azeotropic refrigerant, or a single refrigerant is used as the refrigerant having saturation pressure characteristics higher than R407C, and an accumulator, capable of pooling the surplus refrigerant, which increases and decreases due to the fluctuations of the operating load of the plurality of utilization units, is installed in the low pressure unit having a maximum working pressure of less than 3.3 MPa; consequently, a receiver is no longer needed in the high pressure unit, and parts, such as the bypass pipe for preventing a compositional change in the refrigerant such as the case wherein a non-azeotropic refrigerant is used, are no longer necessary.
  • the air conditioner according to the second invention comprises a compressor, a heat source side heat exchanger, expansion mechanisms, a plurality of utilization side heat exchangers, a switching mechanism, and an accumulator.
  • the compressor compresses low-pressure gas refrigerant and discharges high-pressure gas refrigerant.
  • the heat source side heat exchanger is capable of functioning as an evaporator or a condenser.
  • the plurality of utilization side heat exchangers are mutually connected in parallel, and each is capable of functioning as a condenser or an evaporator.
  • the expansion mechanisms are connected between the utilization side heat exchangers and the heat source side heat exchanger.
  • the switching mechanism is capable of switching between a state wherein the gas side of the heat source side heat exchanger is connected to the discharge side of the compressor, the inlet side of the compressor is connected to the gas side of the utilization side heat exchangers, and low-pressure gas refrigerant is sucked into the compressor, and a state wherein the gas side of the heat source side heat exchanger is connected to the inlet side of the compressor, the discharge side of the compressor is connected to the gas side of the utilization side heat exchangers, and high-pressure gas refrigerant flows to the utilization side heat exchangers.
  • the accumulator is connected between the switching mechanism and the inlet side of the compressor, and is capable of pooling low-pressure refrigerant as a liquid refrigerant.
  • the low pressure unit which includes the accumulator and is constituted by the connection of the switching mechanism and the inlet side of the compressor, can flow only low-pressure refrigerant at a maximum working pressure of less than 3.3 MPa.
  • the high pressure unit which is a part that excludes the low pressure unit and is constituted by the connection of the compressor, the heat source side heat exchanger, the plurality of utilization side heat exchangers, and the switching mechanism, can flow high-pressure refrigerant at a maximum working pressure of 3.3 MPa or higher.
  • the refrigerant that flows through the low pressure unit and the high pressure unit is a pseudo azeotropic refrigerant, an azeotropic refrigerant, or a single refrigerant having saturation pressure characteristics higher than R407C.
  • the standard working pressure of the high pressure unit is approximately 2.0 MPa. Consequently, if R407C is used as the working refrigerant, then it is often the case in an air conditioner that the maximum working pressure of the high pressure unit is set to 3.0-3.3 MPa, which is a pressure approximately 1 MPa higher than the standard working pressure of 2.0 MPa. Consequently, in the air conditioner that uses R407C as the working refrigerant, it is preferable that the parts constituting the high pressure unit have a compressive strength that can withstand 3.3 MPa.
  • the parts constituting the high pressure unit must have a compressive strength that can withstand a pressure of 3.3 MPa or higher because the maximum working pressure of the high pressure unit exceeds 3.3 MPa.
  • a raw material of the thick wall that satisfies the maximum working pressure condition is normally selected and fabricated from among standard products, such as JIS standard products. Consequently, by using a refrigerant having saturation pressure characteristics higher than R407C, the wall thickness unfortunately increases substantially, and the cost of the parts constituting the refrigerant circuit unfortunately increases unnecessarily.
  • a pseudo azeotropic refrigerant, an azeotropic refrigerant, or a single refrigerant is used as the refrigerant having saturation pressure characteristics higher than R407C, and an accumulator, capable of pooling the surplus refrigerant, which increases and decreases due to the fluctuations of the operating load of the plurality of utilization side heat exchangers, is installed in the low pressure unit having a maximum working pressure of less than 3.3 MPa; consequently, a receiver is no longer needed in the high pressure unit, and parts, such as the bypass pipe for preventing a compositional change in the refrigerant such as the case wherein a non-azeotropic refrigerant is used, are no longer necessary.
  • the air conditioner according to the third invention is the air conditioner according to the second invention, further comprising a heat source side temperature detector, utilization side temperature detectors, and a high pressure pressure detector.
  • the heat source side temperature detector detects a refrigerant temperature on the liquid side of the heat source side heat exchanger.
  • a utilization side temperature detector detects a refrigerant temperature on the liquid side of each of the utilization side heat exchangers.
  • the high pressure pressure detector detects a refrigerant pressure on the discharge side of the compressor.
  • the opening of the expansion mechanism is regulated so that the liquid refrigerant on the liquid side of the heat source side heat exchanger reaches a prescribed subcooled state when the heat source side heat exchanger functions as a condenser
  • the opening of each expansion mechanism is regulated so that the liquid refrigerant on the liquid side of the each utilization side heat exchanger reaches a prescribed subcooled state when the utilization side heat exchanger functions as the condenser.
  • the surplus refrigerant which increases and decreases according to the operating load, can be reliably pooled in the accumulator by setting the condensed refrigerant to a prescribed subcooled state when the heat source side heat exchanger functions as the condenser during cooling operation.
  • the surplus refrigerant which increases and decreases according to the operating load, can be reliably pooled in the accumulator by setting the condensed refrigerant to a prescribed subcooled state, even when the utilization side heat exchanger functions as the condenser during heating operation.
  • the air conditioner to the fourth invention is the air conditioner as recited in any one invention of the first invention through the third invention, wherein the refrigerant that flows through the low pressure unit and the high pressure unit includes R32.
  • the air conditioning capacity can be improved because a refrigerant is used that includes R32, which has a high heat transport performance.
  • the air conditioner to the fifth invention is the air conditioner as recited in any one invention of the first invention through the third invention, wherein the refrigerant that flows through the low pressure unit and the high pressure unit is R410A.
  • the air conditioning capacity can be improved more than when using R407C because R410A is used.
  • FIG. 1 is a schematic view of the refrigerant circuit of the air conditioner of one embodiment according to the present invention.
  • FIG. 2 is a Mollier diagram that depicts the refrigerating cycle of the air conditioner.
  • FIG. 3 is a chart that depicts the relationship between the working pressure and the wall thickness.
  • FIG. 1 is a schematic view of the refrigerant circuit of an air conditioner 1 according to one embodiment of the present invention.
  • the air conditioner 1 is, for example, an apparatus used in the cooling and heating of a building and the like, and comprises a heat source unit 2 , a plurality of utilization units 5 (two units in the present embodiment) connected in parallel thereto, and a liquid refrigerant connecting pipe 6 and a gas refrigerant connecting pipe 7 for connecting the heat source unit 2 and the utilization units 5 .
  • the air conditioner 1 uses R410A (50 wt % of R32 and 50 wt % of R125), which is a pseudo azeotropic refrigerant having saturation pressure characteristics higher than R407C, as the working refrigerant.
  • R410A includes more R32, which has high heat transport performance, than does R407C, which improves the air conditioning capacity of the air conditioner 1 .
  • Each utilization unit 5 principally comprises a utilization side expansion valve 51 , a utilization side heat exchanger 52 , and a pipe connecting them.
  • the utilization side expansion valve 51 is an electric expansion valve connected on the liquid side of the utilization side heat exchanger 52 in order to regulate the refrigerant pressure, regulate the refrigerant flow, and the like.
  • the utilization side heat exchanger 52 is a heat exchanger that functions as a refrigerant evaporator during cooling operation to cool the indoor air, and functions as a refrigerant condenser during heating operation to heat the indoor air.
  • the utilization side heat exchanger 52 is provided with a utilization side temperature detector 53 that detects the refrigerant temperature.
  • the utilization side temperature detector 53 is a thermistor disposed on the liquid side of the utilization side heat exchanger 52 .
  • the heat source unit 2 principally comprises a compressor 21 , a four-way switching valve 22 , a heat source side heat exchanger 23 , a heat source side expansion valve 24 , an accumulator 25 , a liquid side gate valve 26 , a gas side gate valve 27 , and pipes that connect them.
  • the compressor 21 is a variable capacity compressor that compresses low-pressure gas refrigerant and discharges high-pressure gas refrigerant.
  • a high pressure pressure detector 28 comprising a pressure sensor that detects the pressure of the high-pressure gas refrigerant is provided on the discharge side of the compressor 21 .
  • the four-way switching valve 22 is a valve that switches the direction of the flow of the refrigerant when switching between cooling operation and heating operation; during cooling operation, the discharge side of the compressor 21 and the gas side of the heat source side heat exchanger 23 can be connected, and the inlet side of the compressor 21 (specifically, the accumulator 25 ) and the gas refrigerant connecting pipe 7 side can be connected (refer to the solid line of the four-way switching valve 22 in FIG. 1 ); and during heating operation, the discharge side of the compressor 21 and the gas refrigerant connecting pipe 7 side can be connected, and the inlet side of the compressor 21 and the gas side of the heat source side heat exchanger 23 can be connected (refer to the broken line of the four-way switching valve 22 in FIG. 1 ).
  • the heat source side heat exchanger 23 is a heat exchanger that functions as a refrigerant condenser during cooling operation with the outdoor air or water as the heat source, and functions as a refrigerant evaporator during heating operation with the outdoor air or water as the heat source.
  • the heat source side heat exchanger 23 is provided with a heat source side temperature detector 29 that detects the refrigerant temperature.
  • the heat source side temperature detector 29 is a thermistor disposed on the liquid side of the heat source side heat exchanger 23 .
  • the heat source side expansion valve 24 is connected on the liquid side of the heat source side heat exchanger 23 and, in the present embodiment, is an electric expansion valve for regulating the refrigerant flow between the heat source side heat exchanger 23 and the utilization side heat exchanger 52 , and the like.
  • the accumulator 25 is connected between the four-way switching valve 22 and the compressor 21 , and is a vessel for pooling the low-pressure refrigerant and the surplus refrigerant sucked into the compressor 21 .
  • the liquid side gate valve 26 and the gas side gate valve 27 are respectively connected to the liquid refrigerant connecting pipe 6 and the gas refrigerant connecting pipe 7 .
  • the liquid refrigerant connecting pipe 6 is connected between the liquid side of the utilization side heat exchanger 52 of each utilization unit 5 and the liquid side of the heat source side heat exchanger 23 of the heat source unit 2 .
  • the gas refrigerant connecting pipe 7 is connected between the gas side of the utilization side heat exchanger 52 of each utilization unit 5 and the four-way switching valve 22 of the heat source unit 2 .
  • the refrigerant circuit wherein are successively connected the utilization side expansion valves 51 , the utilization side heat exchangers 52 , the compressor 21 , the four-way switching valve 22 , the heat source side heat exchanger 23 , the heat source side expansion valve 24 , the accumulator 25 , the liquid side gate valve 26 , and the gas side gate valve 27 , as explained above, constitutes a refrigerant circuit 10 of the air conditioner 1 .
  • FIG. 2 is a Mollier diagram that depicts the refrigerating cycle of the air conditioner 1 .
  • the four-way switching valve 22 is in the state depicted by the solid line in FIG. 1 , i.e., the discharge side of the compressor 21 and the gas side of the heat source side heat exchanger 23 are connected, and the inlet side of the compressor 21 and the gas side of the utilization side heat exchangers 52 are connected.
  • the liquid side gate valve 26 and the gas side gate valve 27 are opened, and the utilization side expansion valves 51 are fully opened.
  • the heat source side expansion valve 24 is in a state wherein the opening can be regulated by the subcooling control based on the high pressure pressure detector 28 and the heat source side temperature detector 29 .
  • a degree of subcooling of the high-pressure liquid refrigerant is calculated based on the temperature differential between a saturation temperature corresponding to a pressure value of the high-pressure gas refrigerant detected by the high pressure pressure detector 28 and a temperature value of the high-pressure liquid refrigerant detected by the heat source side temperature detector 29 , and the opening of the heat source side expansion valve 24 can be regulated so that the degree of subcooling reaches a prescribed value.
  • the high-pressure gas refrigerant is sent to the heat source side heat exchanger 23 via the four-way switching valve 22 , is heat exchanged with the outdoor air or water that forms the heat source, is condensed, and is cooled to a temperature Tc (approximately 45° C.) slightly lower than the saturation temperature Tsat (approximately 50° C.) at pressure Pd (refer to the point C in FIG. 2 ).
  • the high pressure liquid refrigerant subcooling temperature ⁇ Tc in the point C state i.e., Tsat ⁇ Tc
  • Tsat ⁇ Tc the high pressure liquid refrigerant subcooling temperature ⁇ Tc in the point C state
  • the state change is maintained as in the refrigerating cycle depicted in FIG. 2 and the surplus refrigerant pools in the accumulator 25 , even if the operating load of each utilization unit 5 fluctuates, changing the amount of refrigerant circulating.
  • R410A which is one of the pseudo azeotropic refrigerants, is used as the working refrigerant in the present embodiment, the refrigerant composition of the low-pressure gas refrigerant sucked into the compressor 21 and the refrigerant composition of the liquid refrigerant that pooled in the accumulator 25 are maintained at a constant level by the vapor-liquid separation inside the accumulator 25 .
  • the four-way switching valve 22 is in the state indicated by the broken line in FIG. 1 , i.e., the discharge side of the compressor 21 is connected to the gas side of the utilization side heat exchangers 52 , and the inlet side of the compressor 21 is connected to the gas side of the heat source side heat exchanger 23 .
  • the liquid side gate valve 26 and the gas side gate valve 27 are opened, and the heat source side expansion valve 24 is in a full-open state.
  • Each utilization side expansion valve 51 is in a state wherein the valve opening can be regulated by the subcooling control based on the high pressure pressure detector 28 and the respective utilization side temperature detector 53 .
  • the degree of subcooling of the high-pressure liquid refrigerant is calculated based on the temperature differential between the saturation temperature corresponding to the pressure value of the high-pressure gas refrigerant detected by the high pressure pressure detector 28 and the temperature value of the high-pressure liquid refrigerant detected by the respective utilization side temperature detector 53 , and the opening of the respective utilization side expansion valve 51 can be regulated so that the degree of subcooling reaches a prescribed value.
  • the compressor 21 If the compressor 21 is activated in this refrigerant circuit 10 state, the low-pressure gas refrigerant is sucked into and compressed by the compressor 21 , becomes a high-pressure gas refrigerant, and is then sent to the each utilization unit 5 via the four-way switching valve 22 , the gas side gate valve 27 , and the gas refrigerant connecting pipe 7 . Furthermore, the high-pressure gas refrigerant sent to each utilization unit 5 is heat exchanged with the indoor air and condensed in the utilization side heat exchanger 52 , and is cooled to a temperature slightly lower than the saturation temperature of the high-pressure gas refrigerant.
  • the degree of subcooling of the high-pressure liquid refrigerant in the point C state is maintained at a constant level by the subcooling control based on the respective utilization side expansion valve 51 .
  • the pressure of this condensed liquid refrigerant is reduced in accordance with the opening of the respective utilization side expansion valve 51 , becomes a low-pressure vapor-liquid two-phase refrigerant, and is sent to the heat source unit 2 via the liquid refrigerant connecting pipe 6 and the liquid side gate valve 26 .
  • the vapor-liquid two-phase refrigerant sent to the heat source unit 2 passes through the heat source side expansion valve 24 , its heat is exchanged with the outdoor air or water, which forms the heat source, by the heat source side heat exchanger 23 , is then evaporated, once again becomes a low-pressure gas refrigerant, and flows into the accumulator 25 via the four-way switching valve 22 . Furthermore, the low-pressure gas refrigerant that flowed into the accumulator 25 once again is sucked into the compressor 21 .
  • the refrigerant flows during heating operation in a direction the opposite of the flow during cooling operation; in addition, although there is a point of difference in that subcooling control is performed by the utilization side expansion valve 51 , the refrigerant state change is the same as the refrigerating cycle state change as shown in FIG. 2 .
  • the refrigerant circuit 10 comprises a high pressure unit 10 a , which is a refrigerant circuit part wherein high-pressure refrigerant flows, and a low pressure unit 10 b , which is a refrigerant circuit part wherein only low-pressure refrigerant flows.
  • the low pressure unit 10 b is a part that includes the accumulator 25 and wherein the four-way switching valve 22 and the inlet side of the compressor 21 are connected; and the high pressure unit 10 a is the part of the refrigerant circuit 10 that does not include the low pressure unit 10 b.
  • the parts that constitute the high pressure unit 10 a (specifically, the compressor 21 , the four-way switching valve 22 , the heat source side heat exchanger 23 , the heat source side expansion valve 24 , the liquid side gate valve 26 , the gas side gate valve 27 , the utilization side expansion valves 51 , and the utilization side heat exchangers 52 ) and the piping are designed taking into consideration a margin of approximately 1 MPa with respect to the standard working pressure (approximately 3.0 MPa) of the abovementioned high-pressure refrigerant so that high-pressure refrigerant can flow at the maximum working pressure (approximately 4 MPa).
  • the parts that constitute the low pressure unit 10 b (specifically, the accumulator 25 ) and the piping are designed taking into consideration a margin of approximately 1 MPa with respect to the standard working pressure (approximately 0.9 MPa) of the abovementioned low-pressure refrigerant, so that low-pressure refrigerant can flow at the maximum working pressure (approximately 2 MPa).
  • the air conditioner 1 of the present embodiment has the following features.
  • R410A is used as the refrigerant having saturation pressure characteristics higher than R407C; and an accumulator 25 , capable of pooling surplus refrigerant that increases and decreases due to fluctuations in the operating load of the plurality of utilization units 5 , is installed in the low pressure unit 10 b , which has a maximum working pressure of less than 3.3 MPa.
  • schedule 20 raw material can be used up to a working pressure of 3.3 MPa
  • schedule 30 raw material can be used up to 4.3 MPa.
  • schedule 20 raw material can be selected because it has sufficient compressive strength.
  • the maximum working pressure of the receiver is approximately 4.0 MPa (the maximum working pressure of the high pressure unit 10 a )
  • schedule 20 raw material cannot be used; moreover, schedule 30 raw material must be selected regardless of the fact that the approximately 7.4 mm wall thickness is sufficient based on calculations.
  • the maximum working pressure of the high pressure unit is 3.0-3.3 MPa if R407C is used as the working refrigerant of the air conditioner, it is possible to use schedule 20 raw material; however, in a case wherein a refrigerant is used, as in the present embodiment, having saturation pressure characteristics higher than R407C, such as R410A, the use of the receiver as the vessel that pools the surplus refrigerant results in a substantial increase in wall thickness, which unfortunately increases the cost of the parts that constitute the refrigerant circuit unnecessarily.
  • R410A is a pseudo azeotropic refrigerant
  • parts such as the bypass pipe are no longer necessary to prevent compositional changes in the refrigerant, such as in the case wherein a non-azeotropic refrigerant like R407C is used, even if using the accumulator 25 as the vessel that pools the surplus refrigerant, and it is therefore possible to prevent an increase in the cost of the parts that constitute the refrigerant circuit.
  • the degree of subcooling based on the high-pressure liquid refrigerant is calculated during cooling operation in the air conditioner 1 based on the temperature differential between the pressure value of the high-pressure gas refrigerant detected by the high pressure pressure detector 28 and the temperature value of the high-pressure liquid refrigerant detected by the heat source side temperature detector 29 , and the opening of the heat source side expansion valve 24 can be regulated so that the degree of subcooling reaches a prescribed value; consequently, the surplus refrigerant, which increases and decreases according to the operating load, can be reliably pooled in the accumulator 25 .
  • the degree of subcooling based on the high-pressure liquid refrigerant during heating operation is calculated based on the temperature differential between the pressure value of the high-pressure gas refrigerant detected by the high pressure pressure detector 28 and the temperature value of the high-pressure liquid refrigerant detected by the utilization side temperature detector 53 , and the opening of the utilization side expansion valve 51 can be regulated so that the degree of subcooling reaches a prescribed value; consequently, the surplus refrigerant, which increases and decreases according to the operating load, can be reliably pooled in the accumulator 25 .
  • the air conditioner of the abovementioned embodiment uses a refrigerant circuit capable of cooling and heating operation; however, the present invention is not limited thereto, and may be applied to an air conditioner having a refrigerant circuit dedicated for cooling or for heating that does not use a 4-way switching valve.
  • R410A which is one type of pseudo azeotropic refrigerant
  • R410B R32:45 wt %, R125:55 wt %
  • a single refrigerant like R32 and other pseudo azeotropic refrigerants or azeotropic refrigerants.
  • the use of the present invention enables, in an air conditioner comprising a plurality of utilization units, the prevention of a cost increase in the parts constituting the refrigerant circuit, even if the maximum working pressure of the refrigerant circuit increases, by the use of a refrigerant having saturation pressure characteristics higher than R407C.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
US10/523,780 2003-06-06 2004-05-31 Air conditioner Abandoned US20060000224A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2003-161934 2003-06-06
JP2003161934A JP2004361036A (ja) 2003-06-06 2003-06-06 空気調和装置
PCT/JP2004/007490 WO2004109199A1 (ja) 2003-06-06 2004-05-31 空気調和装置

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US20060000224A1 true US20060000224A1 (en) 2006-01-05

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US (1) US20060000224A1 (zh)
EP (1) EP1632732B1 (zh)
JP (1) JP2004361036A (zh)
KR (1) KR100605797B1 (zh)
CN (1) CN100419344C (zh)
AT (1) ATE541167T1 (zh)
AU (1) AU2004245797B2 (zh)
ES (1) ES2380331T3 (zh)
WO (1) WO2004109199A1 (zh)

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US20110252818A1 (en) * 2008-12-29 2011-10-20 Daikin Industries, Ltd. Air conditioning apparatus and method of controlling the air conditioning apparatus
US20120312045A1 (en) * 2011-06-10 2012-12-13 Samsung Electronics Co., Ltd. Water supply apparatus
US20140026603A1 (en) * 2012-07-30 2014-01-30 Fujitsu General Limited Outdoor unit for air-conditioning apparatus, and air-conditioning apparatus
US20170080773A1 (en) * 2008-11-03 2017-03-23 Arkema France Vehicle Heating and/or Air Conditioning Method
US9631847B2 (en) 2011-10-04 2017-04-25 Mitsubishi Electric Corporation Refrigeration cycle apparatus
US11365335B2 (en) 2017-12-18 2022-06-21 Daikin Industries, Ltd. Composition comprising refrigerant, use thereof, refrigerating machine having same, and method for operating said refrigerating machine
US11435118B2 (en) 2017-12-18 2022-09-06 Daikin Industries, Ltd. Heat source unit and refrigeration cycle apparatus
US11441819B2 (en) 2017-12-18 2022-09-13 Daikin Industries, Ltd. Refrigeration cycle apparatus
US11441802B2 (en) 2017-12-18 2022-09-13 Daikin Industries, Ltd. Air conditioning apparatus
US11492527B2 (en) 2017-12-18 2022-11-08 Daikin Industries, Ltd. Composition containing refrigerant, use of said composition, refrigerator having said composition, and method for operating said refrigerator
US11493244B2 (en) 2017-12-18 2022-11-08 Daikin Industries, Ltd. Air-conditioning unit
US11506425B2 (en) 2017-12-18 2022-11-22 Daikin Industries, Ltd. Refrigeration cycle apparatus
US11535781B2 (en) 2017-12-18 2022-12-27 Daikin Industries, Ltd. Refrigeration cycle apparatus
US11549041B2 (en) 2017-12-18 2023-01-10 Daikin Industries, Ltd. Composition containing refrigerant, use of said composition, refrigerator having said composition, and method for operating said refrigerator
US11549695B2 (en) 2017-12-18 2023-01-10 Daikin Industries, Ltd. Heat exchange unit
US11820933B2 (en) 2017-12-18 2023-11-21 Daikin Industries, Ltd. Refrigeration cycle apparatus
US11906207B2 (en) 2017-12-18 2024-02-20 Daikin Industries, Ltd. Refrigeration apparatus

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JP5138292B2 (ja) * 2007-07-04 2013-02-06 三菱重工業株式会社 空気調和装置
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WO2012042573A1 (ja) * 2010-09-30 2012-04-05 三菱電機株式会社 空気調和装置
JP2016102631A (ja) * 2014-11-28 2016-06-02 パナソニックＩｐマネジメント株式会社 空気調和装置
WO2019123897A1 (ja) * 2017-12-18 2019-06-27 ダイキン工業株式会社 冷凍サイクル装置
CN110953779B (zh) * 2019-12-20 2021-06-22 潍柴动力股份有限公司 朗肯循环系统的储液罐压力的控制方法和装置
KR20230168821A (ko) 2022-06-08 2023-12-15 임종봉 R410a가스 절연변압기

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US20170080773A1 (en) * 2008-11-03 2017-03-23 Arkema France Vehicle Heating and/or Air Conditioning Method
US10808157B2 (en) 2008-11-03 2020-10-20 Arkema France Vehicle heating and/or air conditioning method
US20110252818A1 (en) * 2008-12-29 2011-10-20 Daikin Industries, Ltd. Air conditioning apparatus and method of controlling the air conditioning apparatus
US20120312045A1 (en) * 2011-06-10 2012-12-13 Samsung Electronics Co., Ltd. Water supply apparatus
US9631847B2 (en) 2011-10-04 2017-04-25 Mitsubishi Electric Corporation Refrigeration cycle apparatus
US20140026603A1 (en) * 2012-07-30 2014-01-30 Fujitsu General Limited Outdoor unit for air-conditioning apparatus, and air-conditioning apparatus
US9518755B2 (en) * 2012-07-30 2016-12-13 Fujitsu General Limited Outdoor unit for air-conditioning apparatus, and air-conditioning apparatus
US11435118B2 (en) 2017-12-18 2022-09-06 Daikin Industries, Ltd. Heat source unit and refrigeration cycle apparatus
US11365335B2 (en) 2017-12-18 2022-06-21 Daikin Industries, Ltd. Composition comprising refrigerant, use thereof, refrigerating machine having same, and method for operating said refrigerating machine
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US11506425B2 (en) 2017-12-18 2022-11-22 Daikin Industries, Ltd. Refrigeration cycle apparatus
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US11549041B2 (en) 2017-12-18 2023-01-10 Daikin Industries, Ltd. Composition containing refrigerant, use of said composition, refrigerator having said composition, and method for operating said refrigerator
US11549695B2 (en) 2017-12-18 2023-01-10 Daikin Industries, Ltd. Heat exchange unit
US11820933B2 (en) 2017-12-18 2023-11-21 Daikin Industries, Ltd. Refrigeration cycle apparatus
US11906207B2 (en) 2017-12-18 2024-02-20 Daikin Industries, Ltd. Refrigeration apparatus

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WO2004109199A1 (ja) 2004-12-16
KR20050044931A (ko) 2005-05-13
CN100419344C (zh) 2008-09-17
AU2004245797A1 (en) 2004-12-16
JP2004361036A (ja) 2004-12-24
ES2380331T3 (es) 2012-05-10
AU2004245797B2 (en) 2006-06-29
EP1632732B1 (en) 2012-01-11
ATE541167T1 (de) 2012-01-15
KR100605797B1 (ko) 2006-08-01
CN1723373A (zh) 2006-01-18
EP1632732A1 (en) 2006-03-08
EP1632732A4 (en) 2006-07-26

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