REFRIGERANT CYCLE DEVICE

• US 20120255319A1
• Filed: 04/03/2012
• Published: 10/11/2012
• Est. Priority Date: 04/04/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Itoh, Satoshi, Inaba, Atsushi, Kuwahara, Mikiharu
• Granted Patent: US 8,984,903 B2
• Time in Patent Office: Days
• US Class Current: 62/160
• CPC Class Codes: B60H 1/00807 the input being a specific way of measuring or calculating an air or coolant temperature
• CPC Class Codes: B60H 1/00921 where the flow direction of the refrigerant does not change and there is an extra subcondenser, e.g. in an air duct
• CPC Class Codes: F24F 3/1405 in which the humidity of the air is exclusively affected by contact with the evaporator of a closed-circuit cooling system or heat pump circuit
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 41/20 Disposition of valves, e.g. of on-off valves or flow control valves expansion valves F25B41/31
• CPC Class Codes: F25B 41/24 Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
• CPC Class Codes: F25B 41/385 Dispositions with two or more expansion means arranged in parallel on a refrigerant line leading to the same evaporator
• CPC Class Codes: F25B 41/39 Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
• CPC Class Codes: F25B 49/022 Compressor control arrangements

Abstract

A refrigerant cycle device includes a first refrigerant passage for guiding refrigerant from a refrigerant radiator to an inlet side of an outdoor heat exchanger, a first throttle part capable of varying an opening area of the first refrigerant passage, a second refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to a compressor-suction side, a first opening/closing part for opening/closing the second refrigerant passage, a third refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to the compressor-suction side via an evaporator, a second throttle part capable of varying an opening area of the third refrigerant passage, a bypass passage for guiding the refrigerant flowing between the refrigerant radiator and the first throttle part to a position between the outdoor heat exchanger and the second throttle part in the third refrigerant passage, and a second opening/closing part for opening/closing the bypass passage.

Claims

1. A refrigerant cycle device for an air conditioner that performs a dehumidifying operation of cooling and dehumidifying feed air to be blown into a space to be air-conditioned and of heating the dehumidified feed air, the refrigerant cycle device comprising:

a compressor which compresses and discharges refrigerant;

a refrigerant radiator disposed to make refrigerant discharged from the compressor exchange heat with the feed air to thereby radiate an amount of heat of the refrigerant discharged from the compressor;

an outdoor heat exchanger disposed to make the refrigerant flowing out of the refrigerant radiator exchange heat with outdoor air;

an evaporator disposed to make the refrigerant flowing out of the outdoor heat exchanger exchange heat with the feed air before passing through the refrigerant radiator to thereby evaporate the refrigerant flowing out of the outdoor heat exchanger;

a first refrigerant passage provided to guide the refrigerant flowing out of the refrigerant radiator to an inlet side of the outdoor heat exchanger;

a first throttle part that is arranged in the first refrigerant passage to be capable of changing a passage opening area of the first refrigerant passage;

a second refrigerant passage provided to guide the refrigerant flowing out of the outdoor heat exchanger to a suction side of the compressor;

a first opening/closing part that is arranged in the second refrigerant passage and that opens or closes the second refrigerant passage;

a third refrigerant passage provided to guide the refrigerant flowing out of the outdoor heat exchanger to the suction side of the compressor via the evaporator;

a second throttle part that is arranged between the outdoor heat exchanger and the evaporator in the third refrigerant passage to be capable of changing a passage opening area of the third refrigerant passage;

a bypass passage provided to guide the refrigerant flowing between the refrigerant radiator and the first throttle part to a position between the outdoor heat exchanger and the second throttle part in the third refrigerant passage; and

a second opening/closing part that is arranged in the bypass passage and that opens or closes the bypass passage.

2. The refrigerant cycle device as in claim 1, wherein

the second refrigerant passage is closed by the first opening/closing part and the bypass passage is closed by the second opening/closing part, in a first dehumidifying and heating mode, and

the second refrigerant passage is opened by the first opening/closing part and the bypass passage is opened by the second opening/closing part, in a second dehumidifying and heating mode.

3. The refrigerant cycle device as in claim 2, wherein

in the first dehumidifying and heating mode, as a target temperature of air blown off into the space to be air-conditioned is increased, the first throttle part decreases the passage opening area of the first refrigerant passage, and

in the first dehumidifying and heating mode, as the target temperature of air blown off into the space to be air-conditioned is increased, the second throttle part increases the passage opening area of the third refrigerant passage.

4. The refrigerant cycle device as in claim 2, wherein

in the second dehumidifying and heating mode, the first throttle part varies the passage opening area of the first refrigerant passage in such a way that a degree of superheat of the refrigerant on an outlet side of the outdoor heat exchanger becomes a target degree of superheat which is determined in advance.

5. The refrigerant cycle device as in claim 1, further comprising

a constant-pressure adjusting part that is arranged on an outlet side of the evaporator in the third refrigerant passage and keeps a pressure of the refrigerant on an outlet side of the evaporator at a specified value.

6. The refrigerant cycle device as in claim 1, further comprising

a back-flow preventing part that is arranged in the third refrigerant passage, to allow a flow of the refrigerant from an outlet side of the outdoor heat exchanger to an inlet side of the second throttle part, and to prevent a flow of the refrigerant from the inlet side of the second throttle part to the outlet side of the outdoor heat exchanger.

7. A refrigerant cycle device for an air conditioner that performs a dehumidifying operation of cooling and dehumidifying feed air to be blown into a space to be air-conditioned and of heating the dehumidified air, the refrigerant cycle device comprising:

a compressor which compresses and discharges refrigerant;

a refrigerant radiator disposed to make a high-pressure refrigerant discharged from the compressor exchange heat with the feed air to thereby radiate heat of the high-pressure refrigerant;

an outdoor heat exchanger disposed to make the refrigerant flowing out of the refrigerant radiator exchange heat with outdoor air;

an evaporator disposed to make a low-pressure refrigerant passing therein exchange heat with the feed air before passing through the refrigerant radiator to thereby evaporate the low-pressure refrigerant;

a first throttle part configured to reduce pressure of the refrigerant flowing into the outdoor heat exchanger and being capable of varying a throttle opening;

a second throttle part configured to reduce pressure of the refrigerant flowing into the evaporator and being capable of varying a throttle opening;

a constant-pressure adjusting part configured to keep a pressure of the refrigerant flowing out of the evaporator at a specified value which is determined in advance; and

a refrigerant passage switching part configured to switch at least between a first refrigerant passage and a second refrigerant passage in a refrigerant cycle, wherein

the first refrigerant passage makes the refrigerant flowing out of the refrigerant radiator flow in order of;

the first throttle part→

a the outdoor heat exchanger→

the second throttle part→

the evaporator→

the constant-pressure adjusting part→

a suction side of the compressor, and

the second refrigerant passage makes the refrigerant flowing out of the refrigerant radiator flow in order of;

the first throttle part→

the outdoor heat exchanger→

the suction side of the compressor and at the same time makes the refrigerant flowing out of the refrigerant radiator flow in order of the second throttle part→

the evaporator→

the constant-pressure adjusting part→

the suction side of the compressor.

8. The refrigerant cycle device as in claim 7, further comprising:

a bypass passage that makes the refrigerant flowing out of the refrigerant radiator bypass the first throttle part and the outdoor heat exchanger and guides the refrigerant to an inlet side of the second throttle part;

a second refrigerant passage that guides the refrigerant flowing out of the outdoor heat exchanger to a refrigerant outlet side of the constant-pressure adjusting part and the inlet side of the compressor;

a third refrigerant passage that guides the refrigerant flowing out of the outdoor heat exchanger to the inlet side of the compressor via the evaporator; and

a back-flow preventing part that is arranged in the third refrigerant passage and that allows a flow of the refrigerant from an outlet side of the outdoor heat exchanger to an inlet side of the evaporator and prevents a flow of the refrigerant from the inlet side of the evaporator to the outlet side of the outdoor heat exchanger,

wherein a first opening/closing part for opening or closing the second refrigerant passage and a second opening/closing part for opening or closing the bypass passage are provided as the refrigerant passage switching part.

9. The refrigerant cycle device as in claim 7, further comprising:

an outdoor air temperature detecting part provided to detect an outdoor air temperature, wherein

when the outdoor air temperature is higher than an outdoor air reference temperature which is determined in advance, the refrigerant passage switching part switches the refrigerant cycle to the first refrigerant passage, and

when the outdoor air temperature is lower than the outdoor air reference temperature, the refrigerant passage switching part switches the refrigerant cycle to the second refrigerant passage.

10. The refrigerant cycle device as in claim 7, further comprising;

a blowoff temperature detecting part configured to detect a blowoff temperature of the feed air blown off into the space to be air-conditioned; and

a target blowoff temperature determining part configured to determine a target blowoff temperature of the feed air blown off into the space to be air-conditioned, wherein

when a temperature difference obtained by subtracting the target blowoff temperature from the blowoff temperature is lower than a reference value, the refrigerant passage switching part switches the refrigerant cycle to the first refrigerant passage, and

when the temperature difference is higher than the reference value, the refrigerant passage switching part switches the refrigerant cycle to the second refrigerant passage.

11. The refrigerant cycle device as in claim 7, further comprising:

a blowoff temperature detecting part configured to detect a blowoff temperature of the feed air blown off into the space to be air-conditioned;

a target blowoff temperature determining part configured to determine a target blowoff temperature of the feed air blown off into the space to be air-conditioned;

an evaporator temperature detecting part configured to detect an evaporator blowoff temperature of the feed air blown off from the evaporator; and

a target evaporator temperature determining part configured to determine a target evaporator temperature of the feed air blown off from the evaporator, wherein

when the refrigerant passage switching part switches the refrigerant cycle to the first refrigerant passage, one of the first and second throttle parts and the compressor is operated in such a way that the blowoff temperature comes close to the target blowoff temperature and the other of the first and second throttle parts and the compressor is operated in such a way that the evaporator temperature comes close to the target evaporator temperature.

12. The refrigerant cycle device as in claim 7, further comprising:

a blowoff temperature detecting part configured to detect a blowoff temperature of the feed air blown off into the space to be air-conditioned;

a target blowoff temperature determining part configured to determine a target blowoff temperature of the feed air blown off into the space to be air-conditioned;

a super-cooling detecting part configured to detect a physical amount correlated with a degree of super-cooling of the refrigerant on an outlet side of the refrigerant radiator;

a target super-cooling determining part configured to determine a target degree of super-cooling of the refrigerant on the outlet side of the refrigerant radiator;

a superheat detecting part configured to detect a physical amount correlated with a degree of superheat of the refrigerant on an outlet side of the evaporator; and

a target superheat determining part configured to determine a target degree of superheat of the refrigerant on the outlet side of the evaporator, wherein

when the refrigerant passage switching part switches the refrigerant cycle to the second refrigerant passage, (i) the compressor is controlled in such a way that the blowoff temperature comes close to the target blowoff temperature, (ii) the first throttle part is controlled in such a way that the degree of super-cooling comes close to the target degree of super-cooling, and (iii) the second throttle part is controlled in such a way that the degree of superheat comes close to the target degree of superheat.

13. The refrigerant cycle device as in claim 7, further comprising:

a blowoff temperature detecting part configured to detect a blowoff temperature of the feed air blown off into the space to be air-conditioned;

a target blowoff temperature determining part configured to determine a target blowoff temperature of the feed air blown off into the space to be air-conditioned;

an evaporator temperature detecting part configured to detect an evaporator temperature of the feed air blown off from the evaporator;

a target evaporator temperature determining part configured to determine a target evaporator blowoff temperature of the feed air blown off from the evaporator;

a super-cooling detecting part configured to detect a physical amount correlated with a degree of super-cooling of the refrigerant on an outlet side of the refrigerant radiator; and

a target super-cooling determining part configured to determine a target degree of super-cooling of the refrigerant on the outlet side of the refrigerant radiator, wherein

when the refrigerant passage switching part switches the refrigerant cycle to the second refrigerant passage, (i) the compressor is controlled in such a way that the blowoff temperature comes close to the target blowoff temperature, (ii) one of the first throttle part and the second throttle part is controlled in such a way that the degree of super-cooling comes close to the target degree of super-cooling, and (iii) the other of the first throttle part and the second throttle part is controlled in such a way that the evaporator blowoff temperature comes close to the target evaporator blowoff temperature.

14. A refrigerant cycle device comprising:

a compressor configured to suck, compress, and discharge refrigerant;

a refrigerant radiator disposed to radiate heat of the refrigerant discharged from the compressor to thereby heat an external fluid;

a first pressure reducing part disposed to reduce pressure of the refrigerant flowing out of the refrigerant radiator to thereby expand the refrigerant;

an evaporator disposed to evaporate the refrigerant reduced in pressure by the first pressure reducing part to thereby absorb heat from the external fluid; and

a second pressure reducing part that reduces pressure of the refrigerant evaporated by the evaporator and to be sucked by the compressor and that is configured to vary an amount of pressure reduction, wherein

one of an amount of the refrigerant discharged from the compressor and an amount of pressure reduction of the refrigerant of the second pressure reducing part is adjusted in such a way that a heating capacity of the refrigerant radiator or a value of a physical amount related to the heating capacity becomes equal to a heating target value, and

the other of the amount of the refrigerant discharged from the compressor and the amount of pressure reduction of the refrigerant of the second pressure reducing part is adjusted in such a way that a heat absorbing capacity of the evaporator or a value of a physical amount related to the heat absorbing capacity becomes equal to a heat-absorption target value.

15. The refrigerant cycle device as in claim 14, further comprising:

a control part for controlling the amount of discharge of the refrigerant of the compressor on the basis of the heating capacity or the value of the physical amount related to the heating capacity, wherein

the second pressure reducing part is a constant-pressure valve that prevents a refrigerant pressure in the evaporator from becoming less than a specified pressure even if pressure of the refrigerant sucked by the compressor becomes lower,

the control part controls the amount of discharge of the refrigerant in such a way that the heating capacity or the value of the physical amount related to the heating capacity becomes equal to the heating target value, and

the second pressure reducing part adjusts the amount of pressure reduction of the refrigerant in such a way that the heat absorbing capacity or the physical amount related to the heat absorbing capacity becomes equal to the heat-absorption target value.

16. The refrigerant cycle device as in claim 14, further comprising:

a control part for controlling the amount of discharge of the refrigerant of the compressor and the amount of pressure reduction of the refrigerant of the second pressure reducing part on the basis of the heating capacity or the value of the physical amount related to the heating capacity and the heat absorbing capacity or the value of physical amount related to the heat absorbing capacity, wherein

the control part controls one of the amount of discharge of the refrigerant and the amount of pressure reduction of the refrigerant in such a way that the heating capacity or the value of the physical amount related to the heating capacity becomes equal to the heating target value, and

the control part controls the other of the amount of discharge of the refrigerant and the amount of pressure reduction of the refrigerant in such a way that the heat absorbing capacity or the value of the physical amount related to the heat absorbing capacity becomes equal to the heat-absorption target value.

17. The refrigerant cycle device as in claim 16, wherein

the second pressure reducing part includes a fixed throttle valve having a throttle fixed, and an opening/closing valve that is arranged in parallel to the fixed throttle valve and that is switched between an opened state and a closed state, and

the control part switches between the opened state and the closed state of the opening/closing valve to control the amount of pressure reduction of the refrigerant.

18. The refrigerant cycle device as in claim 14, wherein

the refrigerant radiator and the evaporator are arranged in a duct in such a way that the evaporator is arranged on a more upstream side of a flow of the air than the refrigerant radiator,

the evaporator is configured to absorb heat from the air to dehumidify the air, and

the refrigerant radiator is configured to heat the air flowing from the evaporator.