CA2610421A1 - Oil-free liquid chiller - Google Patents
Oil-free liquid chiller Download PDFInfo
- Publication number
- CA2610421A1 CA2610421A1 CA002610421A CA2610421A CA2610421A1 CA 2610421 A1 CA2610421 A1 CA 2610421A1 CA 002610421 A CA002610421 A CA 002610421A CA 2610421 A CA2610421 A CA 2610421A CA 2610421 A1 CA2610421 A1 CA 2610421A1
- Authority
- CA
- Canada
- Prior art keywords
- refrigerant
- condenser
- motor
- bearing
- variable speed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
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- Y02B30/741—
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- Structures Of Non-Positive Displacement Pumps (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
- Compressor (AREA)
Abstract
A refrigeration chiller employs a centrifugal compressor the impellers of which are mounted on a shaft which it itself mounted for rotation using rolling element bearings lubricated only by the refrigerant which constitutes the working fluid of the chiller system. Apparatus is taught for providing liquid refrigerant to the bearings immediately upon chiller start-up, during chiller operation and during a coastdown period subsequent to shut down of the chiller and the driver motor of the chiller's compressor for motor cooling purposes. By use of a variable speed-driven motor to drive the compressor, optimized part load chiller performance is achieved in a chiller which does not require or employ an oil-based lubrification system.
Claims (50)
1. A liquid chiller comprising:
a condenser, said condenser condensing refrigerant gas to the liquid state when said chiller is in operation;
a metering device, said metering device receiving refrigerant from said condenser;
an evaporator, said evaporator receiving refrigerant from said metering device;
a compressor, said compressor receiving refrigerant from said evaporator and delivering refrigerant in the gaseous state to said condenser when said chiller is in operation;
a motor, said motor driving said compressor and being cooled by refrigerant sourced from said condenser;
a variable speed drive, said variable speed drive being electrically connected to said compressor drive motor for varying the speeds thereof, refrigerant being delivered from said condenser to said variable speed drive so as to cool said variable speed drive.
a condenser, said condenser condensing refrigerant gas to the liquid state when said chiller is in operation;
a metering device, said metering device receiving refrigerant from said condenser;
an evaporator, said evaporator receiving refrigerant from said metering device;
a compressor, said compressor receiving refrigerant from said evaporator and delivering refrigerant in the gaseous state to said condenser when said chiller is in operation;
a motor, said motor driving said compressor and being cooled by refrigerant sourced from said condenser;
a variable speed drive, said variable speed drive being electrically connected to said compressor drive motor for varying the speeds thereof, refrigerant being delivered from said condenser to said variable speed drive so as to cool said variable speed drive.
2. The chiller according to claim 1 further comprising a pump, said pump pumping refrigerant from said condenser to said variable speed drive so as to cool said variable speed drive.
3. The chiller according to claim 2 wherein refrigerant delivered by said pump to said variable speed drive is returned therefrom to said condenser.
4. The chiller according to claim 3 wherein refrigerant pumped from said condenser by said pump is pumped in parallel to both said compressor drive motor and to said variable speed drive.
5. The chiller according to claim 3 wherein refrigerant pumped by said pump from said condenser is pumped in series to both said compressor drive motor and to said variable speed drive.
6. The chiller according to claim 3 wherein said compressor includes at least one bearing, said at least one bearing being a rolling element bearing, the rolling elements of said bearing being fabricated from a non-metallic material, said at least one bearing being lubricated by refrigerant in the absence of oil, referigerant delivered to said at least one bearing for lubrication purposes being at least primarily in the liquid state and a portion of the refrigerant used in the lubrication of said at least one bearing vaporizing at the location of said at least one bearing as a result of the bearing lubrication process, said pump pumping refrigerant from said condenser to said at least one bearing for bearing lubrication purposes.
7. The chiller according to claim 6 further comprising a reservoir, refrigerant pumped by said pump from said at least one bearing being pumped to said reservoir prior to flowing to said at least one bearing.
8. The chiller according to claim 7 wherein refrigerant pumped by said pump from said condenser is additionally pumped to 0said compressor drive motor, the refrigerant pumped to said variable speed drive being pumped to said reservoir prior to flowing to said variable speed drive.
9. The chiller according to claim 8 wherein refrigerant delivered to said at least one bearing for bearing lubrication purposes drains, subsequent to being used for lubrication purposes to a location in said compressor drive motor and is returned therefrom, together with refrigerant used for motor cooling purposes, to said condenser.
10. The chiller according to claim 3 wherein said pump pumps refrigerant to said compressor drive motor so as to cool said motor and further comprising apparatus for regulating the flow of refrigerant pumped by said pump to said compressor drive motor and to said variable speed drive in accordance with the conditions under which said chiller is operating.
11. The chiller according to claim 3 wherein said motor is an induction motor, wherein, in addition to pumping refrigerant to said variable speed drive, said pump pumps refrigerant to said compressor drive motor so as to cool said motor, said pump increasing the pressure of refrigerant pumped by it from said condenser to a pressure which is higher than condenser pressure, and wherein heat rejected to refrigerant pumped by said pump to said compressor drive motor and to said variable speed drive is carried therein back to said condenser, said condenser transferring such heat, which has a parasitic effect on the efficiency of said chiller, to the cooling medium which flows through said condenser.
12. The liquid chiller according to claim 1 further comprising a pump, wherein refrigerant is pumped by said pump from said condenser to both said compressor drive motor and to said variable speed drive so as to cool said compressor drive motor and said variable speed drive, said pump increasing the pressure of refrigerant pumped by it from said condenser to a pressure which is higher than condenser pressure, and wherein heat rejected to refrigerant pumped by said pump to said compressor drive motor and said variable speed drive is carried therein back to said condenser, said condenser transferring such heat, which has a parasitic effect on the efficiency of said chiller, to the cooling medium which flows through said condenser.
13. The liquid chiller according to claim 12 wherein said compressor includes at least one bearing, said bearing being lubricated by refrigerant in the absence of oil, the refrigerant used to lubricate said at least one bearing in the absence of oil being refrigerant pumped thereto from said condenser by said pump.
14. The liquid chiller according to claim 13 vherein said pump pumps liquid refrigerant from said condenser, in parallel, to said at least one bearing and to said compressor drive motor, the liquid refrigerant pumped to said variable speed drive by said pump being pumped thereto in parallel with refrigerant pumped by said pump to said compressor drive motor.
15. A method of operating the liquid chiller comprising the steps of:
connecting a condenser, a metering device, an evaporator and a compressor for flow so as to form a refrigeration circuit;
flowing a cooling medium through said condenser so as to carry heat thereoutof;
driving said compressor by the use of a motor;
controlling the speed of said motor by the use of a variable speed drive which includes heat generating components;
delivering refrigerant from said condenser to said at least one of said compressor drive motor and said variable speed drive;
rejecting heat from said at least one of said compressor drive motor and said variable speed drive to the refrigerant delivered in said delivering step;
returning refrigerant to which heat has been rejected in said rejecting step to said condenser; and transferring heat carried back to said condenser in said returning step to the cooling medium which flows through said condenser.
connecting a condenser, a metering device, an evaporator and a compressor for flow so as to form a refrigeration circuit;
flowing a cooling medium through said condenser so as to carry heat thereoutof;
driving said compressor by the use of a motor;
controlling the speed of said motor by the use of a variable speed drive which includes heat generating components;
delivering refrigerant from said condenser to said at least one of said compressor drive motor and said variable speed drive;
rejecting heat from said at least one of said compressor drive motor and said variable speed drive to the refrigerant delivered in said delivering step;
returning refrigerant to which heat has been rejected in said rejecting step to said condenser; and transferring heat carried back to said condenser in said returning step to the cooling medium which flows through said condenser.
16. The method according to claim 15 wherein said delivering step includes the step of pumping refrigerant from said condenser to said at least one of said motor and said variable speed drive.
17. The chiller according to claim 16 wherein said pumping step includes the step of pumping refrigerant in parallel from said condenser to both of said motor and said variable speed drive.
18. The method according to claim 16 wherein said pumping step includes the step of pumping refrigerant in series from said condenser to both of said compressor drive motor and variable speed drive.
19. The method according to claim 16 wherein said compressor includes a bearing and wherein said pumping step includes the step of pumping refrigerant from said condenser to said bearing so as to lubricate said bearing.
20. The method according to claim 19 wherein said chiller includes a reservoir and wherein said pumping step includes the step of delivering refrigerant to said reservoir prior to its delivery to said bearing for bearing lubrication purposes.
21. The method according to claim 20 comprising the further step of isolating refrigerant in said reservoir from a drop in pressure upstream thereof so that pressurized refrigerant continues to be available from said reservoir to lubricate said bearing for a predetermined period of time in the event of a pressure drop upstream of said reservoir.
22. The method according to claim 21 comprising the further step of delivering refrigerant from said reservoir to said variable speed drive so as to cool said variable speed drive.
23. The method according to claim 19 comprising the further step of defining a flow path from said bearing to said motor so that refrigerant used to lubricate said bearing flows to said motor and returns to said condenser, in said returning step, with refrigerant used to cool said drive motor.
24. The method according to claim 16 comprising the further step of regulating the flow of refrigerant pumped in said pumping step in accordance with chiller operating conditions.
25. The method according to claim 15 wherein said driving step includes the step of driving said compressor directly so that said compressor is driven at the same rotational speed as the rotor of said drive motor.
26. A liquid chiller comprising:
a condenser for condensing refrigerant gas to a liquid state when said chiller is in operation;
a metering device arranged to receive refrigerant from said condenser for reducing the pressure thereof;
an evaporator arranged to receive refrigerant from said metering device;
a compressor arranged to receive refrigerant from said evaporator and deliver refrigerant in a gaseous state to said condenser when said chiller is in operation; and a motor for driving said compressor, said motor being cooled by refrigerant sourced from said condenser; and characterized in that a variable speed drive is electrically connected to said compressor motor for varying the speed thereof, refrigerant being delivered from said condenser to said variable speed drive so as to cool said variable speed drive.
a condenser for condensing refrigerant gas to a liquid state when said chiller is in operation;
a metering device arranged to receive refrigerant from said condenser for reducing the pressure thereof;
an evaporator arranged to receive refrigerant from said metering device;
a compressor arranged to receive refrigerant from said evaporator and deliver refrigerant in a gaseous state to said condenser when said chiller is in operation; and a motor for driving said compressor, said motor being cooled by refrigerant sourced from said condenser; and characterized in that a variable speed drive is electrically connected to said compressor motor for varying the speed thereof, refrigerant being delivered from said condenser to said variable speed drive so as to cool said variable speed drive.
27. A chiller according to claim 26, further comprising a pump, said pump being arranged to pump refrigerant from said condenser to said variable speed drive so as to cool said variable speed drive.
28. A chiller according to claim 27, wherein refrigerant delivered by said pump to said variable speed drive is returned therefrom to said condenser.
29. A chiller according to claims 27 or 28, wherein refrigerant pumped from said condenser by said pump is pumped in parallel to both said motor and said variable speed drive.
30. A chiller according to claims 27 or 28, wherein refrigerant pumped by said pump from said condenser is pumped in series to both said motor and to said variable speed drive.
31. A chiller according to any one of claims 27 to 30, wherein said compressor includes at least one rolling element bearing that has rolling elements fabricated from a non-metallic material, said pump pumping refrigerant from said condenser to said at least one bearing to provide lubrication by refrigerant in the absence of oil, refrigerant delivered to said at least one bearing for lubrication purposes being at least primarily in the liquid state and a portion of the refrigerant used in the lubrication of said at least one bearing vaporizing at the location of said at least one bearing as a result of the bearing lubrication process.
32. A chiller according to claim 31, further comprising a reservoir, refrigerant pumped by said pump to said at least one bearing being pumped to said reservoir prior to flowing to said at least one bearing.
33. A chiller according to claim 32, wherein the refrigerant pumped by said pump from said condenser to said variable speed drive is pumped to said reservoir prior to flowing to said variable speed drive.
34. A chiller according to claims 31, 32 or 33, wherein refrigerant delivered to said at least one bearing for bearing lubrication purposes drains, subsequent to being used for lubrication purposes, to a location in said motor and is returned therefrom, together with the refrigerant used for motor cooling purposes, to said condenser.
35. A chiller according to claims 27 or 28, wherein said pump pumps refrigerant to said motor so as to cool said motor and further comprising valving for regulating the flow of refrigerant pumped by said pump to said motor and to said variable speed drive in accordance with the conditions under which said chiller is operating.
36. A chiller according to claims 27, 28 or 35, wherein said motor is an induction motor, said pump pumps refrigerant to said motor so as to cool said motor, said pump increasing the pressure of refrigerant pumped by it from said condenser to a pressure which is higher than condenser pressure, and wherein heat rejected to refrigerant pumped by said pump to said motor and to said variable speed drive is carried therein back to said condenser, said condenser transferring such heat to the cooling medium which flows through said condenser.
37. A liquid chiller according to claim 26, further comprising a pump, wherein refrigerant is pumped by said pump from said condenser to both said motor and to said variable speed drive so as to cool said motor and said variable speed drive, said pump increasing the pressure of refrigerant pumped by it from said condenser to a pressure which is higher than condenser pressure, and wherein heat rejected to refrigerant pumped by said pump to said motor and said variable speed drive is carried therein back to said condenser, said condenser transferring such heat to the cooling medium which flows through said condenser.
38. A liquid chiller according to claim 37, wherein said compressor includes at least one bearing having non-metallic rolling elements, said bearing being lubricated by refrigerant in the absence of oil, the refrigerant used to lubricate said at least one bearing in the absence of oil being refrigerant pumped thereto from said condenser by said pump.
39. A liquid chiller according to claim 38, wherein said pump pumps liquid refrigerant from said condenser, in parallel to said at least one bearing and to said motor, the liquid refrigerant pumped to said variable speed drive by said pump being pumped thereto in parallel with refrigerant pumped by said pump to said motor.
40. A method of operating a liquid chiller that comprises:
a condenser, a metering device, an evaporator and a compressor connected to form a refrigeration circuit; and a motor for driving said compressor and a variable speed drive, which is for controlling the speed of said motor and includes heat generating components; said method comprising the steps of:
flowing a cooling medium through said condenser so as to carry heat therefrom;
driving said compressor by the use of said motor;
controlling the speed of said motor by the use of said variable speed drive;
delivering refrigerant from said condenser to at least one of said motor and said variable speed drive, which refrigerant receives heat from said at least one of said compressor drive motor and said variable speed drive; and returning said refrigerant which has received said heat to said condenser such that said heat can be transferred to said cooling medium which flows through said condenser.
a condenser, a metering device, an evaporator and a compressor connected to form a refrigeration circuit; and a motor for driving said compressor and a variable speed drive, which is for controlling the speed of said motor and includes heat generating components; said method comprising the steps of:
flowing a cooling medium through said condenser so as to carry heat therefrom;
driving said compressor by the use of said motor;
controlling the speed of said motor by the use of said variable speed drive;
delivering refrigerant from said condenser to at least one of said motor and said variable speed drive, which refrigerant receives heat from said at least one of said compressor drive motor and said variable speed drive; and returning said refrigerant which has received said heat to said condenser such that said heat can be transferred to said cooling medium which flows through said condenser.
41. A method according to claim 40, wherein said delivering step includes the step of pumping refrigerant from said condenser to said at least one of said motor and said variable speed drive.
42. A method according to claim 41, wherein said pumping step includes the step of pumping refrigerant in parallel from said condenser to both of said motor and said variable speed drive.
43. A method according to claim 41, wherein said pumping step includes the step of pumping refrigerant in series from said condenser to both of said motor and variable speed drive.
44. A method according to claims 41, 42 or 43, wherein said compressor includes a bearing having non-metallic rolling elements and wherein said pumping step includes the step of pumping refrigerant from said condenser to said bearing so as to lubricate said bearing.
45. A method according to claim 44, wherein said chiller includes a reservoir and said pumping step includes the step of delivering refrigerant to said reservoir prior to its delivery to said bearing for bearing lubrication purposes.
46. A method according to claim 45, comprising the further step of isolating refrigerant in said reservoir from a drop in pressure upstream thereof so that pressurized refrigerant continues to be available from said reservoir to lubricate said bearing for a predetermined period of time in the event of a pressure drop upstream of said reservoir.
47. A method according to claims 45 or 46, wherein said delivering step further comprises delivering refrigerant to said variable speed drive via said reservoir.
48. A method according to any one of claims 44 to 47, comprising the further step of defining a flow path from said bearing to said motor so that refrigerant used to lubricate said bearing flows to said motor and returns to said condenser, in said returning step, with refrigerant used to cool said motor.
49. A method according to any one of claims 41 to 48, comprising the further step of regulating the flow of refrigerant pumped in said pumping step in accordance with chiller operating conditions.
50. A method according to any one of claims 40 to 49, wherein said driving step comprises driving said compressor directly so that said compressor is driven at the same rotational speed as the rotor of said motor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/169,343 | 1998-10-09 | ||
| US09/169,343 US6176092B1 (en) | 1998-10-09 | 1998-10-09 | Oil-free liquid chiller |
| CA002342909A CA2342909C (en) | 1998-10-09 | 1999-09-15 | Oil-free liquid chiller |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002342909A Division CA2342909C (en) | 1998-10-09 | 1999-09-15 | Oil-free liquid chiller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2610421A1 true CA2610421A1 (en) | 2000-04-20 |
| CA2610421C CA2610421C (en) | 2010-06-29 |
Family
ID=39264338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2610421A Expired - Fee Related CA2610421C (en) | 1998-10-09 | 1999-09-15 | Oil-free liquid chiller |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2610421C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023079936A1 (en) * | 2021-11-03 | 2023-05-11 | Daikin Industries, Ltd. | Centrifugal compressor with reverse overhung volute |
-
1999
- 1999-09-15 CA CA2610421A patent/CA2610421C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023079936A1 (en) * | 2021-11-03 | 2023-05-11 | Daikin Industries, Ltd. | Centrifugal compressor with reverse overhung volute |
| US11953015B2 (en) | 2021-11-03 | 2024-04-09 | Daikin Industries, Ltd. | Centrifugal compressor with reverse overhung volute |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2610421C (en) | 2010-06-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20150915 |