US20090205350A1 - Air conditioning system - Google Patents
Air conditioning system Download PDFInfo
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- US20090205350A1 US20090205350A1 US12/364,899 US36489909A US2009205350A1 US 20090205350 A1 US20090205350 A1 US 20090205350A1 US 36489909 A US36489909 A US 36489909A US 2009205350 A1 US2009205350 A1 US 2009205350A1
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- United States
- Prior art keywords
- refrigerant
- evaporator
- air
- heat
- circulation path
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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
- F25B41/00—Fluid-circulation arrangements
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
- B60H1/00814—Control systems or circuits characterised by their output, for controlling particular components of the heating, cooling or ventilating installation
- B60H1/00878—Control systems or circuits characterised by their output, for controlling particular components of the heating, cooling or ventilating installation the components being temperature regulating devices
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- B60H1/00—Heating, cooling or ventilating [HVAC] devices
- B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
- B60H1/00814—Control systems or circuits characterised by their output, for controlling particular components of the heating, cooling or ventilating installation
- B60H1/00878—Control systems or circuits characterised by their output, for controlling particular components of the heating, cooling or ventilating installation the components being temperature regulating devices
- B60H2001/00928—Control systems or circuits characterised by their output, for controlling particular components of the heating, cooling or ventilating installation the components being temperature regulating devices comprising a secondary circuit
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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
- F25B2339/00—Details of evaporators; Details of condensers
- F25B2339/04—Details of condensers
- F25B2339/047—Water-cooled condensers
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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
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/23—Separators
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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
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2501—Bypass valves
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
Definitions
- the present invention relates to an air conditioning system that can achieve air-heating by using a heat-pump type cooling unit.
- the air conditioning system includes a heat-pump type cooling unit 100 and an air-heating circulation unit 120 .
- the heat-pump type cooling unit 100 has a first circulation path 101 along which first refrigerant circulates.
- the air-heating circulation unit 120 has a second circulation path 121 along which second refrigerant circulates.
- a compressor 102 , a heat-radiating side of an internal heat exchanger 103 , an in-compartment heat exchanger 104 , an expansion valve 105 , an evaporator (external heat exchanger) 106 and a gas-liquid separator 107 are provided on the first circulation path 101 in the heat-pump type cooling unit 100 .
- the in-compartment heat exchanger 104 is provided within an air-conditioning duct 110 .
- a pump 122 for circulating the second refrigerant, a heat-receiving side of the internal heat exchanger 103 and a heater core 123 are provided on the second refrigerant path 121 in the air-heating circulation unit 120 .
- the compressor of the heat-pump type cooling unit 100 and the pump 102 of the air-heating circulation unit 120 are both driven.
- Heat of the first refrigerant is radiated at the in-compartment heat exchanger 104 for air heating.
- the heat of the first refrigerant is conducted to the second refrigerant in the internal heat exchanger 103 .
- heat of the second refrigerant is radiated at the heater core 123 for air heating.
- the cooling unit 100 is driven even at the heating mode and the first refrigerant needs to receive heat from flowing air at the evaporator 106 .
- the first refrigerant is HFC134a
- evaporating pressure of the refrigerant is 1.01 bar (almost atmosphere pressure: 1 atm) at ⁇ 26.2 deg C. and 1.33 bar at ⁇ 20.0 deg C. as shown in FIG. 10 . Therefore, the pressure may be reduced by 0.32 Bar and then the pressure in the first circulation path 101 will be equal-to or lower-than the atmosphere pressure. And then, since the gas-liquid separator 107 is provided between the evaporator 106 and the compressor 102 , the evaporator 106 cannot achieve heat-exchanging if flowing resistance through the gas-liquid separator 107 is equivalent to 0.32 bar. As a result, air heating cannot be achieved.
- An object of the present invention is to provide an air conditioning system that can achieve air-heating by driving a heat-pump type cooling unit even under a condition where outside temperature is very low.
- An aspect of the present invention is to provide an air conditioning system that includes a heat-pump type cooling unit including a first circulation path in which a first refrigerant circulates and an air-heating unit including a second circulation path in which a second refrigerant circulates.
- a compressor for compressing the first refrigerant, a condenser for heat-exchanging between the first refrigerant and the second refrigerant and radiating heat of the first refrigerant, an expansion unit for expanding the first refrigerant, and an evaporator for heat-exchanging between the first refrigerant expanded by the expansion unit and air to cool the air are provided on the first circulation path.
- the air-heating unit achieves air-heating by using heat radiated by the condenser.
- the system further includes a gas-liquid separator provided between the expansion unit and the evaporator for separating the first refrigerant supplied from the expansion unit into first refrigerant gas and first refrigerant liquid and sending the first refrigerant liquid to the evaporator, a bypass path for flowing the first refrigerant gas through the first circulation path with bypassing the evaporator, and a refrigerant liquid flow preventing unit for preventing the first refrigerant liquid from flowing into the evaporator.
- a gas-liquid separator provided between the expansion unit and the evaporator for separating the first refrigerant supplied from the expansion unit into first refrigerant gas and first refrigerant liquid and sending the first refrigerant liquid to the evaporator
- a bypass path for flowing the first refrigerant gas through the first circulation path with bypassing the evaporator
- a refrigerant liquid flow preventing unit for preventing the first refrigerant liquid from flowing into the evaporator.
- the first refrigerant liquid is prevented from flowing into the evaporator by the refrigerant liquid flow preventing unit and only the first refrigerant gas is circulated through the bypass path (the warming-up mode).
- the evaporator does not achieve heat-exchanging but heat quantity equivalent to work of the compressor is used for air-heating. Therefore, air-heating can be achieved even under a condition where outside temperature is very low.
- a pump for circulating the second refrigerant a component container for arranging the condenser also on the second circulation path, a heater core for heating air by heat-exchanging between the second refrigerant and the air, and a radiator for radiating heat of the second refrigerant are provided on the second circulation path.
- the second refrigerant is fluid to achieve heat-exchanging with sensible heat change
- air-heating can be done by way of heat-radiation by the heater core in a hearing mode and air-cooling can be done by way of heat-radiation by the radiator in a cooling mode.
- the condenser is a water-cooling type with higher heat-transfer efficiency than an air-cooling type, it can be down-sized and thereby flowing resistance of the first refrigerant can be reduced.
- driving force for the compressor can be saved and thereby the compressor can be down-sized.
- the refrigerant in the second circulation path does not change its phase in a liquid phase but takes sensible heat change, heat-transfer efficiency can be further improved and down-sizing can be achieved.
- a first orifice and a second orifice are capable of provided on the bypass path alternatively.
- the refrigerant liquid flow preventing unit is a changeover valve capable of moving between a first position and a second position.
- the changeover valve When the changeover valve is set to the first position, the bypass path is communicated with the first circulation path and the first circulation path is blocked so as not to flow the first refrigerant liquid into the evaporator.
- the changeover valve When the changeover valve is set to the second position, the bypass path is communicated with the first circulation path and the first circulation path is opened so as to flow the first refrigerant liquid into the evaporator.
- the changeover valve has a first orifice to make the first refrigerant gas passing through at the first position and a second orifice to make the first refrigerant gas passing through at the first position.
- Flowing resistance of the first orifice is set to be optimum for warming-up mode and flowing resistance of the second orifice is set to be optimum for heating/cooling mode.
- the changeover valve is controlled so that the refrigerant gas passes through the first orifice in the warm-up mode and passes through the second orifice in the heating/cooling mode.
- flow quantity of the refrigerant gas may be differentiated between the warming-up mode and the heating/cooling mode, appropriate flowing resistance can be set for each mode.
- bypass path passes through a position where the first refrigerant liquid is normally held within a refrigerant tank within the gas-liquid separator.
- the inside of the bypass path communicates with the inside of the refrigerant tank through an oil breed hole at the position.
- changeover between the warming-up mode (it is prevented that the first refrigerant liquid flows into the evaporator) and the heating mode (it is allowed that the refrigerant liquid flows into the evaporator) is done based on at least one of intake air temperature into the evaporator and refrigerant pressure at an inlet side of the compressor.
- mode changeover can be done appropriately by way of the mode changeover based on the intake air temperature of the evaporator.
- mode changeover can be done appropriately by way of the mode changeover based on the refrigerant pressure at the inlet side of the compressor.
- FIG. 1 is a configuration diagram of an air conditioning system according to an embodiment of the present invention
- FIG. 2 is a configuration diagram of a gas-liquid separator in the embodiment of the present invention.
- FIG. 3A is a configuration diagram showing a changed-over position of a changeover valve under an warming-up mode in the embodiment of the present invention
- FIG. 3B is a configuration diagram showing a changed-over position of the changeover valve under a heating mode or a cooling mode in the embodiment of the present invention
- FIG. 4 is a configuration diagram of main elements in an air-conditioning duct in the embodiment of the present invention.
- FIG. 5 is a circuit block diagram of a control system in the embodiment of the present invention.
- FIG. 6 is a configuration diagram showing a flow of refrigerant under the idle warming-up mode in the embodiment of the present invention.
- FIG. 7 is a configuration diagram showing a flow of refrigerant under the heating mode in the embodiment of the present invention.
- FIG. 8 is a P-h diagram on which shown is a condition of a heat-pump type cooling unit (refrigeration cycle) in the embodiment of the present invention.
- FIG. 9 is a configuration diagram of a conventional air conditioning system.
- FIG. 10 is a P-h diagram on which shown is a condition of a conventional heat-pump type cooling unit (refrigeration cycle).
- an air conditioning system is combined of a heat-pump type cooling unit A and an air-heating circulation unit B.
- the heat-pump type cooling unit A includes a first circulation path 1 .
- the first circulation path 1 is filled with first refrigerant (HFC134a).
- a compressor 2 a water-cooled condenser 3 , an internal heat exchanger 4 , an expansion valve (expansion unit) 5 , a gas-liquid separator 6 , an evaporator 7 and a changeover valve (refrigerant liquid flow preventing unit) 8 are provided on the first circulation path 1 in this order.
- the compressor 2 inhales the relatively low-temperature and pressure first refrigerant and discharges the high-temperature and pressure first refrigerant after compressing it.
- the water-cooled condenser 3 is arranged within an after-mentioned unit container 13 on the second circulation path 10 .
- the first refrigerant output from the compressor 2 is cooled by the second refrigerant. Specifically, heat-exchanging is achieved between the first refrigerant and the second refrigerant at the water-cooled condenser 3 .
- the second refrigerant is heated by the first refrigerant.
- the internal heat exchanger 4 achieves heat-exchanging between the first refrigerant output from the water-cooled condenser 3 and the low-temperature first refrigerant output from the evaporator 7 .
- the first refrigerant output from the water-cooled condenser 3 is further cooled down.
- the expansion valve 5 expands the first refrigerant (reduce the pressure of the first refrigerant) had passed through the internal heat exchanger 4 and sends it to the gas-liquid separator 6 as a low-temperature and pressure gas.
- the gas-liquid separator 6 separates the first refrigerant output from the expansion valve 5 into gas phase and liquid phase.
- the first refrigerant in the liquid phase is temporally held in the gas-liquid separator 6 .
- Detailed configuration of the gas-liquid separator 6 will be explained later in detail.
- the evaporator 7 achieves heat-exchanging between the first refrigerant liquid output from the gas-liquid separator 6 and air had passed through the evaporator 7 .
- the air had passed through the evaporator 7 is cooled down by the first refrigerant.
- the evaporator 7 is provided within an air-conditioning duct 30 as explained later.
- the changeover valve 8 changes over the flow of the first refrigerant to make the first refrigerant flow into the evaporator 7 or not. Detailed configuration of the changeover valve 8 will be explained later in detail.
- a bypass path 9 for the refrigerant gas is provided in the first circulation path 1 so as to communicate the gas-liquid separator 6 and the changeover valve 8 .
- the air-heating circulation unit B includes a second circulation path 10 .
- the second circulation path 10 is filled with second refrigerant (liquid such as water, antifreeze solution or the like).
- a pump 11 , a radiator 12 , the unit container 13 and a heater core 14 are provided on the second circulation path 10 in this order.
- the unit container 13 is a space having a larger cross-sectional area than that of the second circulation path 10 .
- the above-mentioned water-cooled condenser 3 and an electric heater 15 are contained within the unit container 13 .
- the pump 11 inhales the second refrigerant and then pumps it out in order to circulates it along the second circulation path 10 .
- the second refrigerant liquid pumped by the pump 11 circulates along the second circulation path 10 in liquid phase without changing its phase.
- the second refrigerant takes sensible heat change due to heat-changing.
- the radiator 12 is a unit for radiating heat of the second refrigerant to fresh air.
- the fresh air is blown to the radiator 12 by an electric fan or air flow due to a vehicle running and then heat-exchange is achieved between the second refrigerant and the fresh air.
- the electric heater 15 is provided beneath the water-cooled condenser 13 and heats the second refrigerant by its heat with being energized.
- the heater core 14 heats air passing through it by achieving heat-exchanging between the second refrigerant and the air passing through it.
- the heater core 14 is provided within the air-conditioning duct 30 .
- a radiator-bypass path 16 is provided in the second circulation path 10 so as to bypass the radiator 12 .
- the flow of the second refrigerant can be changed into the radiator 12 or the radiator-bypass path 16 by changing over a flow-path changeover valve 17 provided upstream of the radiator 12 .
- the gas-liquid separator 6 has a refrigerant tank 6 a within its inside as shown in FIG. 2 .
- a refrigerant inlet 1 a is connected at an upper portion of the refrigerant tank 6 a .
- the refrigerant inlet la configures a part of the first circulation path 1 .
- a refrigerant outlet opening 1 b is opened at a lower portion of the refrigerant tank 6 a .
- the refrigerant outlet 1 b is connected to the evaporator 7 and configures a part of the first circulation path 1 .
- the refrigerant liquid is output from the refrigerant outlet 1 b to the evaporator 7 .
- the bypass path 9 for the refrigerant gas is also connected at the upper portion of the refrigerant tank 6 a .
- the refrigerant gas is output through the bypass path 9 to the changeover valve 8 .
- the bypass path 9 is led out of the refrigerant tank 6 a via the lower portion of the refrigerant tank 6 a and a position where the refrigerant liquid is normally held.
- the inside of the bypass path 9 communicates with the inside of the refrigerant tank 6 a through an oil breed hole 9 a at the position where the refrigerant liquid is held.
- the changeover valve 8 has a valve housing 20 as shown in FIGS. 3A and 3B .
- the first circulation path 1 A from the evaporator 7 (“ 1 A” is allocated for distinction in FIGS. 3A and 3B ) and the bypass path 9 are connected to two inlet ports of the valve housing 20 , respectively.
- the first circulation path 1 B led out to the compressor 2 (“ 1 B” is allocated for distinction in FIGS. 3A and 3B ) is connected to two outlet ports of the valve housing 20 .
- a valve element 21 is provided within the valve housing 20 .
- the valve element 21 includes a path 22 for the refrigerant liquid.
- the valve element 21 also includes a first orifice 23 and a second orifice 24 for the refrigerant gas.
- the first orifice 23 has a smaller inner diameter than that of the second orifice 24 .
- the first orifice 23 provides large flowing resistance and the second orifice 24 provides small flowing resistance.
- the flowing resistance of the first orifice 23 is set to be optimum for warming-up mode and the second orifice 24 is set to be optimum for heating/cooling mode.
- the valve element 21 moves between a first position ( FIG. 3A ) and a second position ( FIG. 3B ) according to a changeover command from a controller.
- the refrigerant liquid flowing between the first circulation path 1 A and the first circulation path 1 B is blocked and the refrigerant gas flowing between the bypass path 9 and the first circulation path 1 B is allowed through the first orifice 23 . Therefore, the refrigerant liquid does not flow into the evaporator 7 and only the refrigerant gas circulates in the refrigeration cycle.
- the refrigerant liquid flowing between the first circulation path 1 A and the first circulation path 1 B is allowed and the refrigerant gas flowing between the bypass path 9 and the first circulation path 1 B is also allowed through the second orifice 24 . Therefore, the refrigerant liquid flows into the evaporator 7 and the refrigerant gas circulates in the refrigeration cycle with bypassing the evaporator 7 through the bypass path 9 .
- An air selector door (not shown) and a blower fan 31 are provided within the air-conditioning duct 30 in this order.
- the air selector door is changed its position between an interior-air position for inhaling air inside a vehicle compartment (interior air) and a fresh-air position for inhaling air outside the vehicle compartment (fresh air).
- Interior air or fresh air is inhaled into the air conditioning duct 30 by flowing force of the blower fan 31 .
- the evaporator 7 and the heater core 14 is further provider within the air-conditioning duct 30 in this order.
- a temperature sensor 32 is provided just upstream the evaporator 7 . The temperature sensor 32 detects air temperature before passing through the evaporator 7 (intake air temperature) to output it to the controller 40 (see FIG. 5 ).
- a mixture door 33 is provided between the evaporator 7 and the heater core 14 . The mixture door 33 adjusts how much rate of cooled air from the evaporator 7 to be sent to the heater core 14 . In warming-up mode, full heating mode and so on, entire air passing through the evaporator 7 is sent to the heater core 14 . Air passing-through and bypassing the heater core 14 is blown out from desired ventilation grills.
- an input command (heating operation command, cooling operation command or the like) from a operation unit 41 and a detection signal of the temperature sensor 32 are input to the controller 40 .
- the controller 40 controls the compressor 2 , the pump 11 , door actuators 42 , the changeover valve 8 , the electric heater 15 , the flow-path changeover valve 17 and so on based on the input command by a user, detection information of the temperature sensor 32 or the like.
- the door actuators 42 actuate the air selector door (not shown), the mixture door 33 and so on.
- the controller 40 drives the door actuators 42 to move the mixture door 33 to the position so that entire cooled air from the evaporator 7 will be sent to the heater core 14 ( FIG. 4 ) and to move the air selector door (not shown) to the interior-air position.
- the controller 40 drives the compressor 2 and the pump 11 and controls the flow-path changeover valve 17 so as to flow the refrigerant to the radiator-bypass path 16 .
- the controller 40 gets the detected temperature by the temperature sensor 32 parallel to the above controls.
- the changeover valve 8 is set to the first position ( FIG. 3A ) to achieve the warming-up mode when the detected temperature by the temperature sensor 32 is not more than a predetermined temperature (e.g. ⁇ 20 deg C.). Basically the detected temperature by the temperature sensor 32 at starting-up may be equal to outside temperature.
- the first refrigerant in the heat-pump type cooling unit A is separated into gas phase (refrigerant gas) and liquid phase (refrigerant liquid) by the gas-liquid separator 6 .
- the refrigerant liquid does not flow into the evaporator 7 and only the refrigerant gas circulates in the refrigeration cycle with bypassing the evaporator 7 through the bypass path 9 as shown in FIG. 6 . Therefore, the first refrigerant is heated by heat quantity equivalent to work of the compressor 2 and heat of the first refrigerant is radiated at the water-cooled condenser 3 .
- the second refrigerant in the air-heating circulation unit B is heated by heat-radiation at the water-cooled condenser 3 and heat of the second refrigerant is radiated at the heater core 14 to heat flowing air within the air-conditioning duct 30 .
- the heated air by the heater core 14 is blown out into a vehicle compartment.
- the vehicle compartment can be heated by using the heat-pump type cooling unit A regardless of outside temperature.
- the controller 40 continuously checks the detected temperature by the temperature sensor 32 and changes the changeover valve 8 to the second position ( FIG. 3B ) to achieve the heating mode when the detected temperature becomes more than the predetermined temperature (e.g. ⁇ 20 deg C.) to.
- the predetermined temperature e.g. ⁇ 20 deg C.
- the first refrigerant in the heat-pump type cooling unit A is separated into gas phase (refrigerant gas) and liquid phase (refrigerant liquid) by the gas-liquid separator 6 .
- the refrigerant liquid flows into the evaporator 7 and the refrigerant gas circulates in the refrigeration cycle with bypassing the evaporator 7 through the bypass path 9 as shown in FIG. 7 . Therefore, the first refrigerant is heated by heat quantity equivalent to work of the compressor 2 and condensation of the first refrigerant. Then, heat of the first refrigerant is radiated at the water-cooled condenser 3 .
- the second refrigerant in the air-heating circulation unit B is heated by heat-radiation at the water-cooled condenser 3 and heat of the second refrigerant is radiated at the heater core 14 to heat flowing air within the air-conditioning duct 30 .
- the heated air by the heater core 14 is blown out into a vehicle compartment.
- the refrigerant liquid output from the gas-liquid separator 6 flows into the evaporator 7 for heat-exchanging at the evaporator 7 .
- a refrigerant evaporating pressure at an outlet port of the evaporator 7 can be reduced by a pressure equivalent to flowing resistance reduction due to the gas-liquid separator 6 (between the orifices 23 and 24 ) and bypassing the evaporator 7 as shown in FIG. 8 compared with the conventional system where a gas-liquid separator is provided between an evaporator and a compressor. Therefore, temperature difference between the first refrigerant and the air passing through the evaporator 7 even under a very low temperature condition (e.g. almost ⁇ 20 deg C.) can be made larger than the conventional system.
- a very low temperature condition e.g. almost ⁇ 20 deg C.
- an evaporating temperature of the first refrigerant must be ⁇ 20 deg C. at least as shown in FIG. 10 . Therefore, heat-exchanging for air-heating cannot be achieved if air temperature before passing through the evaporator (intake air temperature) is ⁇ 20 deg C. On the contrary, an evaporating temperature of the first refrigerant can be ⁇ 26.2 deg C. at least in the present embodiment as shown in FIG. 8 . Heat-exchanging for air-heating can be achieved even if the air temperature before passing through the evaporator 7 (intake air temperature) is ⁇ 20 deg C.
- the flow-path changeover valve 17 is changed so as to flow the refrigerant to the radiator 12 . Therefore, heat of the first refrigerant is radiated outside the vehicle compartment by the radiator 12 .
- the mixture door 33 is moved to a position for restricting a flow amount to the heater core 14 . Then, the first refrigerant cools flowing air within the air-conditioning duct 30 by the evaporator. Cooled air air-conditioned with the cooled air by the evaporator 7 and/or heated air passing through the heater core 14 is supplied into the vehicle compartment.
- the pump 11 for circulating the second refrigerant, the component container 13 for arranging the water-cooled condenser 3 on the second circulation path 10 , the heater core 14 for heating air by heat-exchanging between the second refrigerant and the air, the radiator 12 for radiating heat of the second refrigerant are provided, and the second refrigerant is fluid to achieve heat-exchanging with sensible heat change. Therefore, air-heating and air-cooling can be done by way of the heat-radiation by the heater core 14 in the hearing mode and by the radiator 12 in the cooling mode.
- the condenser 3 is a water-cooling type with higher heat-transfer efficiency than an air-cooling type, it can be down-sized and thereby flowing resistance of the first refrigerant can be reduced. As a result, since needed power for driving the compressor 2 can be reduced by the flowing resistance reduction, driving force for the compressor 2 can be saved and thereby the compressor can be down-sized. Furthermore, since the refrigerant in the second circulation path 10 does not change its phase in a liquid phase but takes sensible heat change, heat-transfer efficiency can be further improved and down-sizing can be achieved.
- the refrigerant liquid flow preventing unit is the changeover valve 8 which can be changed over between the first position and the second position.
- the changeover valve 8 When the changeover valve 8 is set to the first position, the bypass path 9 is communicated with the first circulation path 1 and the refrigerant flowing between the first circulation path 1 A and the first circulation path 1 B (see FIGS. 3A and 3B ) is blocked so as not to flow the refrigerant into the evaporator 7 .
- the changeover valve 8 is set to the second position, the bypass path 9 is communicated with the first circulation path 1 and the refrigerant flowing between the first circulation path 1 A and the first circulation path 1 B (see FIGS.
- the first orifice 23 and the second orifice 24 are provided on the bypass path 9 (specifically within the changeover valve 8 ). Even if the refrigerant liquid flows through the bypass path 9 , the refrigerant liquid is gasified again. Therefore, it can be prevented that the refrigerant liquid returns to the compressor 2 .
- the changeover valve 8 includes the first orifice 23 for allowing the refrigerant gas flowing at its first position and the second orifice 24 for allowing the refrigerant gas flowing at its second position.
- the flowing resistance of the first orifice 23 is set adequately for the warming-up mode.
- the flowing resistance of the second orifice 24 is set adequately for the heating/cooling mode.
- flow quantity of the refrigerant gas may be differentiated between the warming-up mode and the heating/cooling mode, appropriate flowing resistance can be set for each mode.
- the bypass path 9 passes through a position where the refrigerant liquid is normally held within the refrigerant tank 6 a of the gas-liquid separator 6 and the inside of the bypass path 9 communicates with the inside of the refrigerant tank 6 a through the oil breed hole 9 a at the position. Therefore, since oil is circulated together with the refrigerant gas downstream the bypass path 9 , the oil can be returned to the compressor 2 even in the warming-up mode. As a result, reliability of the compressor 2 can be ensured.
- changeover between the warming-up mode (it is prevented that the refrigerant liquid flows into the evaporator 7 ) and the heating mode (it is allowed that the refrigerant liquid flows into the evaporator 7 ) is done based on the intake air temperature. Since it depends on the intake air temperature of the evaporator 7 whether or not the evaporator 7 can done appropriate heat-exchanging, mode changeover can be done appropriately by way of the mode changeover based on the intake air temperature of the evaporator 7 .
- changeover control between the warm-up mode and the heating mode may be done based on the refrigerant pressure at the inlet side of the compressor 2 . Since it depends on the refrigerant pressure at the inlet side of the compressor 2 whether or not the refrigerant pressure at the inlet side of the compressor 2 is equal-to or lower-than the atmosphere pressure, mode changeover can be done appropriately by way of the mode changeover based on the refrigerant pressure at the inlet side of the compressor 2 . Note that changeover between the warming-up mode and the heating mode may be done based on both the intake air temperature of the evaporator 7 and the refrigerant pressure at the inlet side of the compressor 2 .
- entire of the cooled air passing through the evaporator 7 is returned to the vehicle compartment in the heating mode.
- entire or some of the cooled air passing through the evaporator 7 may be ejected outside the vehicle compartment.
- heating performance can be improved.
- the electric heater 15 is used.
- the same workings and advantages can be achieved by a combustion heater or the like.
- HFC134a is used as the first refrigerant and water, antifreeze solution or the like is used as the second refrigerant.
- Other refrigerant may be used.
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Abstract
An air conditioning system includes a heat-pump type cooling unit and an air-heating unit. On a first circulation path in the cooling unit, provided are a gas-liquid separator provided between an expansion valve and an evaporator for separating refrigerant supplied from the expansion valve into refrigerant gas and refrigerant liquid and sending the refrigerant liquid to the evaporator, a bypass path for flowing the refrigerant gas through the first circulation path with bypassing the evaporator, and a changeover valve for preventing the refrigerant liquid from flowing into the evaporator. In warming-up mode, only the refrigerant gas is circulated in a refrigeration cycle. According to the system, air-heating can be achieved by driving the cooling unit even under a condition where outside temperature is very low.
Description
- 1. Field of the Invention
- The present invention relates to an air conditioning system that can achieve air-heating by using a heat-pump type cooling unit.
- 2. Description of Related Art
- A conventional air conditioning system is disclosed in Japanese Patent Application Laid-Open Number 2002-98430. As shown in
FIG. 9 , the air conditioning system includes a heat-pumptype cooling unit 100 and an air-heating circulation unit 120. The heat-pumptype cooling unit 100 has afirst circulation path 101 along which first refrigerant circulates. The air-heating circulation unit 120 has asecond circulation path 121 along which second refrigerant circulates. - A
compressor 102, a heat-radiating side of aninternal heat exchanger 103, an in-compartment heat exchanger 104, anexpansion valve 105, an evaporator (external heat exchanger) 106 and a gas-liquid separator 107 are provided on thefirst circulation path 101 in the heat-pumptype cooling unit 100. The in-compartment heat exchanger 104 is provided within an air-conditioning duct 110. Apump 122 for circulating the second refrigerant, a heat-receiving side of theinternal heat exchanger 103 and aheater core 123 are provided on thesecond refrigerant path 121 in the air-heating circulation unit 120. - In a heating mode, the compressor of the heat-pump
type cooling unit 100 and thepump 102 of the air-heating circulation unit 120 are both driven. Heat of the first refrigerant is radiated at the in-compartment heat exchanger 104 for air heating. In addition, the heat of the first refrigerant is conducted to the second refrigerant in theinternal heat exchanger 103. And then, heat of the second refrigerant is radiated at theheater core 123 for air heating. - In the air conditioning system with the heat-pump
type cooling unit 100 as explained above, thecooling unit 100 is driven even at the heating mode and the first refrigerant needs to receive heat from flowing air at theevaporator 106. - However, certain degree of temperature difference should be needed between the temperature of the first refrigerant and the temperature of the passing air through the evaporator in order that adequate heat-changing by the evaporator is achieved. In the above conventional example, it may occasionally happen that the desired temperature difference cannot be obtained under a very low temperature condition.
- Namely, for example the first refrigerant is HFC134a, evaporating pressure of the refrigerant is 1.01 bar (almost atmosphere pressure: 1 atm) at −26.2 deg C. and 1.33 bar at −20.0 deg C. as shown in
FIG. 10 . Therefore, the pressure may be reduced by 0.32 Bar and then the pressure in thefirst circulation path 101 will be equal-to or lower-than the atmosphere pressure. And then, since the gas-liquid separator 107 is provided between theevaporator 106 and thecompressor 102, theevaporator 106 cannot achieve heat-exchanging if flowing resistance through the gas-liquid separator 107 is equivalent to 0.32 bar. As a result, air heating cannot be achieved. - An object of the present invention is to provide an air conditioning system that can achieve air-heating by driving a heat-pump type cooling unit even under a condition where outside temperature is very low.
- An aspect of the present invention is to provide an air conditioning system that includes a heat-pump type cooling unit including a first circulation path in which a first refrigerant circulates and an air-heating unit including a second circulation path in which a second refrigerant circulates. A compressor for compressing the first refrigerant, a condenser for heat-exchanging between the first refrigerant and the second refrigerant and radiating heat of the first refrigerant, an expansion unit for expanding the first refrigerant, and an evaporator for heat-exchanging between the first refrigerant expanded by the expansion unit and air to cool the air are provided on the first circulation path. The air-heating unit achieves air-heating by using heat radiated by the condenser. The system further includes a gas-liquid separator provided between the expansion unit and the evaporator for separating the first refrigerant supplied from the expansion unit into first refrigerant gas and first refrigerant liquid and sending the first refrigerant liquid to the evaporator, a bypass path for flowing the first refrigerant gas through the first circulation path with bypassing the evaporator, and a refrigerant liquid flow preventing unit for preventing the first refrigerant liquid from flowing into the evaporator.
- According to the aspect of the present invention, the first refrigerant liquid is prevented from flowing into the evaporator by the refrigerant liquid flow preventing unit and only the first refrigerant gas is circulated through the bypass path (the warming-up mode). As a result, the evaporator does not achieve heat-exchanging but heat quantity equivalent to work of the compressor is used for air-heating. Therefore, air-heating can be achieved even under a condition where outside temperature is very low.
- It is preferable that a pump for circulating the second refrigerant, a component container for arranging the condenser also on the second circulation path, a heater core for heating air by heat-exchanging between the second refrigerant and the air, and a radiator for radiating heat of the second refrigerant are provided on the second circulation path. The second refrigerant is fluid to achieve heat-exchanging with sensible heat change
- According to this, air-heating can be done by way of heat-radiation by the heater core in a hearing mode and air-cooling can be done by way of heat-radiation by the radiator in a cooling mode. Note that, if the condenser is a water-cooling type with higher heat-transfer efficiency than an air-cooling type, it can be down-sized and thereby flowing resistance of the first refrigerant can be reduced. As a result, since needed power for driving the compressor can be reduced by the flowing resistance reduction, driving force for the compressor can be saved and thereby the compressor can be down-sized. In addition, if the refrigerant in the second circulation path does not change its phase in a liquid phase but takes sensible heat change, heat-transfer efficiency can be further improved and down-sizing can be achieved.
- It is preferable that a first orifice and a second orifice are capable of provided on the bypass path alternatively.
- According to this, even if the refrigerant liquid flows through the bypass path, the refrigerant liquid is gasified again. Therefore, it can be prevented that the refrigerant liquid returns to the compressor.
- It is preferable that the refrigerant liquid flow preventing unit is a changeover valve capable of moving between a first position and a second position. When the changeover valve is set to the first position, the bypass path is communicated with the first circulation path and the first circulation path is blocked so as not to flow the first refrigerant liquid into the evaporator. When the changeover valve is set to the second position, the bypass path is communicated with the first circulation path and the first circulation path is opened so as to flow the first refrigerant liquid into the evaporator.
- According to this, since operation mode (between the warming-up mode and the heating/cooling mode) can be changed over by way of changeover control of the
changeover valve 8, changeover operation can be done easily. - It is further preferable that the changeover valve has a first orifice to make the first refrigerant gas passing through at the first position and a second orifice to make the first refrigerant gas passing through at the first position. Flowing resistance of the first orifice is set to be optimum for warming-up mode and flowing resistance of the second orifice is set to be optimum for heating/cooling mode.
- According to this, the changeover valve is controlled so that the refrigerant gas passes through the first orifice in the warm-up mode and passes through the second orifice in the heating/cooling mode. Although flow quantity of the refrigerant gas may be differentiated between the warming-up mode and the heating/cooling mode, appropriate flowing resistance can be set for each mode.
- It is preferable that the bypass path passes through a position where the first refrigerant liquid is normally held within a refrigerant tank within the gas-liquid separator. The inside of the bypass path communicates with the inside of the refrigerant tank through an oil breed hole at the position.
- According to this, since oil is circulated together with the refrigerant gas downstream the bypass path, the oil can be returned to the compressor even in the warming-up mode. As a result, reliability of the compressor can be ensured.
- It is preferable that changeover between the warming-up mode (it is prevented that the first refrigerant liquid flows into the evaporator) and the heating mode (it is allowed that the refrigerant liquid flows into the evaporator) is done based on at least one of intake air temperature into the evaporator and refrigerant pressure at an inlet side of the compressor.
- According to this, since it depends on the intake air temperature of the evaporator whether or not the evaporator can done appropriate heat-exchanging, mode changeover can be done appropriately by way of the mode changeover based on the intake air temperature of the evaporator.
- Alternatively, since it depends on the refrigerant pressure at the inlet side of the compressor whether or not the refrigerant pressure at the inlet side of the compressor is equal-to or lower-than the atmosphere pressure, mode changeover can be done appropriately by way of the mode changeover based on the refrigerant pressure at the inlet side of the compressor.
-
FIG. 1 is a configuration diagram of an air conditioning system according to an embodiment of the present invention; -
FIG. 2 is a configuration diagram of a gas-liquid separator in the embodiment of the present invention; -
FIG. 3A is a configuration diagram showing a changed-over position of a changeover valve under an warming-up mode in the embodiment of the present invention; -
FIG. 3B is a configuration diagram showing a changed-over position of the changeover valve under a heating mode or a cooling mode in the embodiment of the present invention; -
FIG. 4 is a configuration diagram of main elements in an air-conditioning duct in the embodiment of the present invention; -
FIG. 5 is a circuit block diagram of a control system in the embodiment of the present invention; -
FIG. 6 is a configuration diagram showing a flow of refrigerant under the idle warming-up mode in the embodiment of the present invention; -
FIG. 7 is a configuration diagram showing a flow of refrigerant under the heating mode in the embodiment of the present invention; -
FIG. 8 is a P-h diagram on which shown is a condition of a heat-pump type cooling unit (refrigeration cycle) in the embodiment of the present invention; -
FIG. 9 is a configuration diagram of a conventional air conditioning system; and -
FIG. 10 is a P-h diagram on which shown is a condition of a conventional heat-pump type cooling unit (refrigeration cycle). - Hereinafter, one embodiment according to the present invention will be explained with reference to drawings.
- As shown in
FIG. 1 , an air conditioning system is combined of a heat-pump type cooling unit A and an air-heating circulation unit B. - The heat-pump type cooling unit A includes a
first circulation path 1. Thefirst circulation path 1 is filled with first refrigerant (HFC134a). Acompressor 2, a water-cooledcondenser 3, aninternal heat exchanger 4, an expansion valve (expansion unit) 5, a gas-liquid separator 6, anevaporator 7 and a changeover valve (refrigerant liquid flow preventing unit) 8 are provided on thefirst circulation path 1 in this order. - The
compressor 2 inhales the relatively low-temperature and pressure first refrigerant and discharges the high-temperature and pressure first refrigerant after compressing it. - The water-cooled
condenser 3 is arranged within an after-mentionedunit container 13 on thesecond circulation path 10. The first refrigerant output from thecompressor 2 is cooled by the second refrigerant. Specifically, heat-exchanging is achieved between the first refrigerant and the second refrigerant at the water-cooledcondenser 3. The second refrigerant is heated by the first refrigerant. - The
internal heat exchanger 4 achieves heat-exchanging between the first refrigerant output from the water-cooledcondenser 3 and the low-temperature first refrigerant output from theevaporator 7. The first refrigerant output from the water-cooledcondenser 3 is further cooled down. - The
expansion valve 5 expands the first refrigerant (reduce the pressure of the first refrigerant) had passed through theinternal heat exchanger 4 and sends it to the gas-liquid separator 6 as a low-temperature and pressure gas. - The gas-
liquid separator 6 separates the first refrigerant output from theexpansion valve 5 into gas phase and liquid phase. The first refrigerant in the liquid phase is temporally held in the gas-liquid separator 6. Detailed configuration of the gas-liquid separator 6 will be explained later in detail. - The
evaporator 7 achieves heat-exchanging between the first refrigerant liquid output from the gas-liquid separator 6 and air had passed through theevaporator 7. The air had passed through theevaporator 7 is cooled down by the first refrigerant. Theevaporator 7 is provided within an air-conditioning duct 30 as explained later. - The
changeover valve 8 changes over the flow of the first refrigerant to make the first refrigerant flow into theevaporator 7 or not. Detailed configuration of thechangeover valve 8 will be explained later in detail. - A
bypass path 9 for the refrigerant gas is provided in thefirst circulation path 1 so as to communicate the gas-liquid separator 6 and thechangeover valve 8. - The air-heating circulation unit B includes a
second circulation path 10. Thesecond circulation path 10 is filled with second refrigerant (liquid such as water, antifreeze solution or the like). Apump 11, aradiator 12, theunit container 13 and aheater core 14 are provided on thesecond circulation path 10 in this order. Theunit container 13 is a space having a larger cross-sectional area than that of thesecond circulation path 10. The above-mentioned water-cooledcondenser 3 and anelectric heater 15 are contained within theunit container 13. - The
pump 11 inhales the second refrigerant and then pumps it out in order to circulates it along thesecond circulation path 10. The second refrigerant liquid pumped by thepump 11 circulates along thesecond circulation path 10 in liquid phase without changing its phase. The second refrigerant takes sensible heat change due to heat-changing. - The
radiator 12 is a unit for radiating heat of the second refrigerant to fresh air. The fresh air is blown to theradiator 12 by an electric fan or air flow due to a vehicle running and then heat-exchange is achieved between the second refrigerant and the fresh air. - The
electric heater 15 is provided beneath the water-cooledcondenser 13 and heats the second refrigerant by its heat with being energized. - The
heater core 14 heats air passing through it by achieving heat-exchanging between the second refrigerant and the air passing through it. Theheater core 14 is provided within the air-conditioning duct 30. - A radiator-
bypass path 16 is provided in thesecond circulation path 10 so as to bypass theradiator 12. The flow of the second refrigerant can be changed into theradiator 12 or the radiator-bypass path 16 by changing over a flow-path changeover valve 17 provided upstream of theradiator 12. - The gas-
liquid separator 6 has arefrigerant tank 6 a within its inside as shown inFIG. 2 . Arefrigerant inlet 1 a is connected at an upper portion of therefrigerant tank 6 a. The refrigerant inlet la configures a part of thefirst circulation path 1. A refrigerant outlet opening 1 b is opened at a lower portion of therefrigerant tank 6 a. Therefrigerant outlet 1 b is connected to theevaporator 7 and configures a part of thefirst circulation path 1. the refrigerant liquid is output from therefrigerant outlet 1 b to theevaporator 7. Thebypass path 9 for the refrigerant gas is also connected at the upper portion of therefrigerant tank 6 a. The refrigerant gas is output through thebypass path 9 to thechangeover valve 8. In addition, thebypass path 9 is led out of therefrigerant tank 6 a via the lower portion of therefrigerant tank 6 a and a position where the refrigerant liquid is normally held. The inside of thebypass path 9 communicates with the inside of therefrigerant tank 6 a through anoil breed hole 9 a at the position where the refrigerant liquid is held. - The
changeover valve 8 has avalve housing 20 as shown inFIGS. 3A and 3B . Thefirst circulation path 1A from the evaporator 7 (“1A” is allocated for distinction inFIGS. 3A and 3B ) and thebypass path 9 are connected to two inlet ports of thevalve housing 20, respectively. Thefirst circulation path 1B led out to the compressor 2 (“1B” is allocated for distinction inFIGS. 3A and 3B ) is connected to two outlet ports of thevalve housing 20. Avalve element 21 is provided within thevalve housing 20. Thevalve element 21 includes apath 22 for the refrigerant liquid. Thevalve element 21 also includes afirst orifice 23 and asecond orifice 24 for the refrigerant gas. Thefirst orifice 23 has a smaller inner diameter than that of thesecond orifice 24. Thefirst orifice 23 provides large flowing resistance and thesecond orifice 24 provides small flowing resistance. Specifically, the flowing resistance of thefirst orifice 23 is set to be optimum for warming-up mode and thesecond orifice 24 is set to be optimum for heating/cooling mode. Thevalve element 21 moves between a first position (FIG. 3A ) and a second position (FIG. 3B ) according to a changeover command from a controller. - With respect to the first position shown in
FIG. 3A , the refrigerant liquid flowing between thefirst circulation path 1A and thefirst circulation path 1B is blocked and the refrigerant gas flowing between thebypass path 9 and thefirst circulation path 1B is allowed through thefirst orifice 23. Therefore, the refrigerant liquid does not flow into theevaporator 7 and only the refrigerant gas circulates in the refrigeration cycle. - With respect to the second position shown in
FIG. 3B , the refrigerant liquid flowing between thefirst circulation path 1A and thefirst circulation path 1B is allowed and the refrigerant gas flowing between thebypass path 9 and thefirst circulation path 1B is also allowed through thesecond orifice 24. Therefore, the refrigerant liquid flows into theevaporator 7 and the refrigerant gas circulates in the refrigeration cycle with bypassing theevaporator 7 through thebypass path 9. - Next, configurations within the air-
conditioning duct 30 will be explained. An air selector door (not shown) and ablower fan 31 are provided within the air-conditioning duct 30 in this order. The air selector door is changed its position between an interior-air position for inhaling air inside a vehicle compartment (interior air) and a fresh-air position for inhaling air outside the vehicle compartment (fresh air). Interior air or fresh air is inhaled into theair conditioning duct 30 by flowing force of theblower fan 31. - The
evaporator 7 and theheater core 14 is further provider within the air-conditioning duct 30 in this order. Atemperature sensor 32 is provided just upstream theevaporator 7. Thetemperature sensor 32 detects air temperature before passing through the evaporator 7 (intake air temperature) to output it to the controller 40 (seeFIG. 5 ). Amixture door 33 is provided between theevaporator 7 and theheater core 14. Themixture door 33 adjusts how much rate of cooled air from theevaporator 7 to be sent to theheater core 14. In warming-up mode, full heating mode and so on, entire air passing through theevaporator 7 is sent to theheater core 14. Air passing-through and bypassing theheater core 14 is blown out from desired ventilation grills. - Next, control system of air conditioning system for a vehicle will be explained in outline. As shown in
FIG. 5 , an input command (heating operation command, cooling operation command or the like) from aoperation unit 41 and a detection signal of thetemperature sensor 32 are input to thecontroller 40. Thecontroller 40 controls thecompressor 2, thepump 11,door actuators 42, thechangeover valve 8, theelectric heater 15, the flow-path changeover valve 17 and so on based on the input command by a user, detection information of thetemperature sensor 32 or the like. The door actuators 42 actuate the air selector door (not shown), themixture door 33 and so on. - Next, will be explained behavior of the air conditioning system for a vehicle in the present embodiment under heating operation.
- On generating the heating operation command, the
controller 40 drives thedoor actuators 42 to move themixture door 33 to the position so that entire cooled air from theevaporator 7 will be sent to the heater core 14 (FIG. 4 ) and to move the air selector door (not shown) to the interior-air position. In addition, thecontroller 40 drives thecompressor 2 and thepump 11 and controls the flow-path changeover valve 17 so as to flow the refrigerant to the radiator-bypass path 16. - The
controller 40 gets the detected temperature by thetemperature sensor 32 parallel to the above controls. Thechangeover valve 8 is set to the first position (FIG. 3A ) to achieve the warming-up mode when the detected temperature by thetemperature sensor 32 is not more than a predetermined temperature (e.g. −20 deg C.). Basically the detected temperature by thetemperature sensor 32 at starting-up may be equal to outside temperature. - As mentioned above, the first refrigerant in the heat-pump type cooling unit A is separated into gas phase (refrigerant gas) and liquid phase (refrigerant liquid) by the gas-
liquid separator 6. In the warming-up mode, the refrigerant liquid does not flow into theevaporator 7 and only the refrigerant gas circulates in the refrigeration cycle with bypassing theevaporator 7 through thebypass path 9 as shown inFIG. 6 . Therefore, the first refrigerant is heated by heat quantity equivalent to work of thecompressor 2 and heat of the first refrigerant is radiated at the water-cooledcondenser 3. The second refrigerant in the air-heating circulation unit B is heated by heat-radiation at the water-cooledcondenser 3 and heat of the second refrigerant is radiated at theheater core 14 to heat flowing air within the air-conditioning duct 30. The heated air by theheater core 14 is blown out into a vehicle compartment. - Therefore, the vehicle compartment can be heated by using the heat-pump type cooling unit A regardless of outside temperature.
- Note that, in case where the
electric heater 15 is further used, since the second refrigerant is heated by both heat quantity equivalent to work of thecompressor 2 and heat quantity by theelectric heater 15, heating can be done more quickly. - As the vehicle compartment is warmed up gradually as mentioned above, the detected temperature by the
temperature sensor 32 will gradually increases. Thecontroller 40 continuously checks the detected temperature by thetemperature sensor 32 and changes thechangeover valve 8 to the second position (FIG. 3B ) to achieve the heating mode when the detected temperature becomes more than the predetermined temperature (e.g. −20 deg C.) to. - As mentioned above, the first refrigerant in the heat-pump type cooling unit A is separated into gas phase (refrigerant gas) and liquid phase (refrigerant liquid) by the gas-
liquid separator 6. In the heating mode, the refrigerant liquid flows into theevaporator 7 and the refrigerant gas circulates in the refrigeration cycle with bypassing theevaporator 7 through thebypass path 9 as shown inFIG. 7 . Therefore, the first refrigerant is heated by heat quantity equivalent to work of thecompressor 2 and condensation of the first refrigerant. Then, heat of the first refrigerant is radiated at the water-cooledcondenser 3. The second refrigerant in the air-heating circulation unit B is heated by heat-radiation at the water-cooledcondenser 3 and heat of the second refrigerant is radiated at theheater core 14 to heat flowing air within the air-conditioning duct 30. The heated air by theheater core 14 is blown out into a vehicle compartment. - In the heating mode, the refrigerant liquid output from the gas-
liquid separator 6 flows into theevaporator 7 for heat-exchanging at theevaporator 7. A refrigerant evaporating pressure at an outlet port of theevaporator 7 can be reduced by a pressure equivalent to flowing resistance reduction due to the gas-liquid separator 6 (between theorifices 23 and 24) and bypassing theevaporator 7 as shown inFIG. 8 compared with the conventional system where a gas-liquid separator is provided between an evaporator and a compressor. Therefore, temperature difference between the first refrigerant and the air passing through theevaporator 7 even under a very low temperature condition (e.g. almost −20 deg C.) can be made larger than the conventional system. As a result, heat-exchanging can be achieved efficiently and heating performance in the heating mode can be improved. In the conventional system, an evaporating temperature of the first refrigerant must be −20 deg C. at least as shown inFIG. 10 . Therefore, heat-exchanging for air-heating cannot be achieved if air temperature before passing through the evaporator (intake air temperature) is −20 deg C. On the contrary, an evaporating temperature of the first refrigerant can be −26.2 deg C. at least in the present embodiment as shown inFIG. 8 . Heat-exchanging for air-heating can be achieved even if the air temperature before passing through the evaporator 7 (intake air temperature) is −20 deg C. - Since the refrigerant gas, which can not be contributed to heat-absorption at the
evaporator 7, bypasses theevaporator 7, heat-exchange efficiency of the evaporator can be improved. The heating performance in the heating mode can be improved in this view point. - On generating the cooling operation command (in the cooling mode), almost the same operations are done as the heating mode. The flow-
path changeover valve 17 is changed so as to flow the refrigerant to theradiator 12. Therefore, heat of the first refrigerant is radiated outside the vehicle compartment by theradiator 12. In addition, themixture door 33 is moved to a position for restricting a flow amount to theheater core 14. Then, the first refrigerant cools flowing air within the air-conditioning duct 30 by the evaporator. Cooled air air-conditioned with the cooled air by theevaporator 7 and/or heated air passing through theheater core 14 is supplied into the vehicle compartment. - In the above embodiment, the
pump 11 for circulating the second refrigerant, thecomponent container 13 for arranging the water-cooledcondenser 3 on thesecond circulation path 10, theheater core 14 for heating air by heat-exchanging between the second refrigerant and the air, theradiator 12 for radiating heat of the second refrigerant are provided, and the second refrigerant is fluid to achieve heat-exchanging with sensible heat change. Therefore, air-heating and air-cooling can be done by way of the heat-radiation by theheater core 14 in the hearing mode and by theradiator 12 in the cooling mode. In addition, since thecondenser 3 is a water-cooling type with higher heat-transfer efficiency than an air-cooling type, it can be down-sized and thereby flowing resistance of the first refrigerant can be reduced. As a result, since needed power for driving thecompressor 2 can be reduced by the flowing resistance reduction, driving force for thecompressor 2 can be saved and thereby the compressor can be down-sized. Furthermore, since the refrigerant in thesecond circulation path 10 does not change its phase in a liquid phase but takes sensible heat change, heat-transfer efficiency can be further improved and down-sizing can be achieved. - In the above embodiment, the refrigerant liquid flow preventing unit is the
changeover valve 8 which can be changed over between the first position and the second position. When thechangeover valve 8 is set to the first position, thebypass path 9 is communicated with thefirst circulation path 1 and the refrigerant flowing between thefirst circulation path 1A and thefirst circulation path 1B (seeFIGS. 3A and 3B ) is blocked so as not to flow the refrigerant into theevaporator 7. When thechangeover valve 8 is set to the second position, thebypass path 9 is communicated with thefirst circulation path 1 and the refrigerant flowing between thefirst circulation path 1A and thefirst circulation path 1B (seeFIGS. 3A and 3B ) is allowed so as to flow the refrigerant into theevaporator 7. Therefore, since operation mode (between the warming-up mode and the heating/cooling mode) can be changed over by way of changeover control of thechangeover valve 8, changeover operation can be done easily. - In the above embodiment, the
first orifice 23 and thesecond orifice 24 are provided on the bypass path 9 (specifically within the changeover valve 8). Even if the refrigerant liquid flows through thebypass path 9, the refrigerant liquid is gasified again. Therefore, it can be prevented that the refrigerant liquid returns to thecompressor 2. - In the above embodiment, the
changeover valve 8 includes thefirst orifice 23 for allowing the refrigerant gas flowing at its first position and thesecond orifice 24 for allowing the refrigerant gas flowing at its second position. The flowing resistance of thefirst orifice 23 is set adequately for the warming-up mode. The flowing resistance of thesecond orifice 24 is set adequately for the heating/cooling mode. Although flow quantity of the refrigerant gas may be differentiated between the warming-up mode and the heating/cooling mode, appropriate flowing resistance can be set for each mode. - In the above embodiment, the
bypass path 9 passes through a position where the refrigerant liquid is normally held within therefrigerant tank 6 a of the gas-liquid separator 6 and the inside of thebypass path 9 communicates with the inside of therefrigerant tank 6 a through theoil breed hole 9 a at the position. Therefore, since oil is circulated together with the refrigerant gas downstream thebypass path 9, the oil can be returned to thecompressor 2 even in the warming-up mode. As a result, reliability of thecompressor 2 can be ensured. - In the above embodiment, changeover between the warming-up mode (it is prevented that the refrigerant liquid flows into the evaporator 7) and the heating mode (it is allowed that the refrigerant liquid flows into the evaporator 7) is done based on the intake air temperature. Since it depends on the intake air temperature of the
evaporator 7 whether or not theevaporator 7 can done appropriate heat-exchanging, mode changeover can be done appropriately by way of the mode changeover based on the intake air temperature of theevaporator 7. - In addition, changeover control between the warm-up mode and the heating mode may be done based on the refrigerant pressure at the inlet side of the
compressor 2. Since it depends on the refrigerant pressure at the inlet side of thecompressor 2 whether or not the refrigerant pressure at the inlet side of thecompressor 2 is equal-to or lower-than the atmosphere pressure, mode changeover can be done appropriately by way of the mode changeover based on the refrigerant pressure at the inlet side of thecompressor 2. Note that changeover between the warming-up mode and the heating mode may be done based on both the intake air temperature of theevaporator 7 and the refrigerant pressure at the inlet side of thecompressor 2. - In the above embodiment, entire of the cooled air passing through the
evaporator 7 is returned to the vehicle compartment in the heating mode. However, entire or some of the cooled air passing through theevaporator 7 may be ejected outside the vehicle compartment. When the temperature of the cooled air passing through theevaporator 7 is lower than outside temperature, heating performance can be improved. - In the above embodiment, the
electric heater 15 is used. However, the same workings and advantages can be achieved by a combustion heater or the like. - In the above embodiment, HFC134a is used as the first refrigerant and water, antifreeze solution or the like is used as the second refrigerant. Other refrigerant may be used.
Claims (7)
1. An air conditioning system comprising
a heat-pump type cooling unit including a first circulation path in which a first refrigerant circulates and
an air-heating unit including a second circulation path in which a second refrigerant circulates,
wherein,
on the first circulation path, provided are
a compressor for compressing the first refrigerant,
a condenser for heat-exchanging between the first refrigerant and the second refrigerant and radiating heat of the first refrigerant,
an expansion unit for expanding the first refrigerant, and
an evaporator for heat-exchanging between the first refrigerant expanded by the expansion unit and air to cool the air;
the air-heating unit achieves air-heating by using heat radiated by the condenser; and
the system further comprises
a gas-liquid separator provided between the expansion unit and the evaporator for separating the first refrigerant supplied from the expansion unit into first refrigerant gas and first refrigerant liquid and sending the first refrigerant liquid to the evaporator,
a bypass path for flowing the first refrigerant gas through the first circulation path with bypassing the evaporator, and
a refrigerant liquid flow preventing unit for preventing the first refrigerant liquid from flowing into the evaporator.
2. The air conditioning system according to claim 1 , wherein,
on the second circulation path, provided are
a pump for circulating the second refrigerant,
a component container for arranging the condenser also on the second circulation path,
a heater core for heating air by heat-exchanging between the second refrigerant and the air, and
a radiator for radiating heat of the second refrigerant; and
the second refrigerant is fluid to achieve heat-exchanging with sensible heat change.
3. The air conditioning system according to claim 1 , wherein,
a first orifice and a second orifice are capable of provided on the bypass path alternatively.
4. The air conditioning system according to claim 1 , wherein,
the refrigerant liquid flow preventing unit is a changeover valve capable of moving between a first position and a second position,
when the changeover valve is set to the first position, the bypass path is communicated with the first circulation path and the first circulation path is blocked so as not to flow the first refrigerant liquid into the evaporator, and
when the changeover valve is set to the second position, the bypass path is communicated with the first circulation path and the first circulation path is opened so as to flow the first refrigerant liquid into the evaporator.
5. The air conditioning system according to claim 4 , wherein,
the changeover valve has a first orifice to make the first refrigerant gas passing through at the first position and a second orifice to make the first refrigerant gas passing through at the first position, and
flowing resistance of the first orifice is set to be optimum for warming-up mode and flowing resistance of the second orifice is set to be optimum for heating/cooling mode.
6. The air conditioning system according to claim 1 , wherein,
the bypass path passes through a position where the first refrigerant liquid is normally held within a refrigerant tank within the gas-liquid separator, and
the inside of the bypass path communicates with the inside of the refrigerant tank through an oil breed hole at the position.
7. The air conditioning system according to claim 1 , wherein,
changeover between the warming-up mode, in which it is prevented that the first refrigerant liquid flows into the evaporator, and the heating mode, in which it is allowed that the refrigerant liquid flows into the evaporator, is done based on at least one of intake air temperature into the evaporator and refrigerant pressure at an inlet side of the compressor.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008-033718 | 2008-02-14 | ||
JP2008033718A JP2009190579A (en) | 2008-02-14 | 2008-02-14 | Air conditioning system |
Publications (1)
Publication Number | Publication Date |
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US20090205350A1 true US20090205350A1 (en) | 2009-08-20 |
Family
ID=40677738
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/364,899 Abandoned US20090205350A1 (en) | 2008-02-14 | 2009-02-03 | Air conditioning system |
Country Status (3)
Country | Link |
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US (1) | US20090205350A1 (en) |
EP (1) | EP2090852A2 (en) |
JP (1) | JP2009190579A (en) |
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WO2012008956A1 (en) * | 2010-07-14 | 2012-01-19 | International Truck Intellectual Property Company, Llc | Climate control system for the interior of an electric drive vehicle |
CN103256743A (en) * | 2013-04-18 | 2013-08-21 | 南京瑞柯徕姆环保科技有限公司 | Overlapping type freezing-force circulation refrigeration unit (low pressure side) |
US9242528B2 (en) | 2012-09-20 | 2016-01-26 | Hanon Systems | Heat exchanger arrangement and air conditioning system of a motor vehicle |
US20170120725A1 (en) * | 2015-11-04 | 2017-05-04 | Toyota Motor Engineering & Manufacturing North America, Inc. | Absorption-based system for automotive waste heat recovery |
US20170241679A1 (en) * | 2014-09-02 | 2017-08-24 | Cyclect Electrical Engineering Pte Ltd | Heat recovery system and method |
US20170369080A1 (en) * | 2015-01-13 | 2017-12-28 | Mitsubishi Electric Corporation | Air-conditioning device for vehicle |
US20190011155A1 (en) * | 2017-07-10 | 2019-01-10 | Hanon Systems | Method for operating an air-conditioning system of a motor vehicle |
US20220369509A1 (en) * | 2021-05-12 | 2022-11-17 | Huawei Digital Power Technologies Co., Ltd. | Cooling device |
US11592221B2 (en) | 2020-12-22 | 2023-02-28 | Deere & Company | Two-phase cooling system |
CN117267816A (en) * | 2023-11-03 | 2023-12-22 | 蓝航科技(廊坊)集团有限公司 | Efficient, energy-saving and stable central air conditioner bypass system and intelligent bypass valve |
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KR101342931B1 (en) * | 2011-03-09 | 2013-12-18 | 한라비스테온공조 주식회사 | Heat pump system for vehicle |
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CN103256743A (en) * | 2013-04-18 | 2013-08-21 | 南京瑞柯徕姆环保科技有限公司 | Overlapping type freezing-force circulation refrigeration unit (low pressure side) |
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US20170369080A1 (en) * | 2015-01-13 | 2017-12-28 | Mitsubishi Electric Corporation | Air-conditioning device for vehicle |
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CN117267816A (en) * | 2023-11-03 | 2023-12-22 | 蓝航科技(廊坊)集团有限公司 | Efficient, energy-saving and stable central air conditioner bypass system and intelligent bypass valve |
Also Published As
Publication number | Publication date |
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JP2009190579A (en) | 2009-08-27 |
EP2090852A2 (en) | 2009-08-19 |
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