oil return retentiontc0811.ashraetcs.org/documents/meeting-information...unitary split system gas...

ASHRAE 1721‐RP: Oil Return and Retention in Unitary Split System Gas Lines with HFC and HFO

Refrigerants

PIs: Eckhard A. Groll and James E. Braun

RA: Vatsal Shah

Purdue University

Ray W. Herrick Laboratories

West Lafayette, IN 47907

June 23, 20191/4323 June 2019 RP:1721 Oil Retention in gas lines

Agenda

2/4323 June 2019 RP:1721 Oil Retention in gas lines

• Project Background

• Test Setup

• Modifications

• Oil Injection

• Oil Retention Measurement Method

• Project Schedule

23 June 2019 3/43

Project Background

Objectives• Gain a better understanding with regard to oil retention of interconnecting gas lines used in air‐

conditioning systems.• Develop a user‐friendly modeling tool and engineering design guidelines for sizing refrigerant

piping in unitary split systems.• Collect data for a wide range of tests that considers existing and new refrigerant‐lubricant

combination, different orientation and geometry of refrigerant lines, varying refrigerant flowrates and with different concentrations of oil.

Motivation• The rising applications of variable speed and tandem compressors coupled with emerging

refrigerant‐oil combinations have brought about the importance of additional design parametersto help determine not only the line size but to also give values for oil retention forinterconnecting gas lines of systems running vapor compression cycle.

RP:1721 Oil Retention in gas lines

23 June 2019 4/43

Project Background

Task Overview

Task 1: Literature Review• Papers related to studies carried out in past have been reviewed and reported• Various oil measurement techniques have been studied and reported

Task 2: Development of Test Matrix• Preliminary test matrix has been prepared and reported which considers• PMS has agreed to initiate testing with R134a with POE • Further oils will be selected for the remaining refrigerants based on the results obtained from R134a and POE

Task 3: Design and Construction of Experimental Setup • Construction of the test setup is completed • Results of shakedown test with only refrigerant will be presented in the current meeting

Task 4: Collect R134a/POE Baseline Data• Baseline data will be collected in the upcoming quarter


Agenda


• Test Setup

• Modifications

• Oil Injection




Test Setup

Refrigerant + Oil

Refrigerant

Oil

Sight Tube

Test Section

Sensor (P: Pressure, T : Temperature, M: Mass flow)

Valve

Ball Valve

Air Purge Valve

Pressure Relief Valve

Controller

Liquid Pump

Check Valve

VCO Fitt ing

Pressure Switch

T13

Oil Separator

Flat Plate Heat Exchanger (Condenser)

RefrigerantReceiver

Oil Receiver

Flow Meter

Development Length

DC - motor with VFD

P

Climate Master (3 Ton)

Hot Water Return

Hot Water Supply

Chilled Water Supply


Chilled Water Return

1/2 “

3/4 “

1-1/8 “

Flat Plate Heat

Exchanger (Evaporator)

Oil Separator

P1

P2

T17

P4P5

M2

T11

T18

T19

T14

T15

T12

T22

P3

TanklessWater Heater

T21

T1 VFD

Exp. Tank

VFD M1

Flow Meter

P6 T16

Oil Separator

ProcessedWater fromBuildingSupply

VFD

Water Reheater

with Buffer Tank


Chilled Water (T = 5 °C)

T20

Sub-cooler

T2

T3

T5

T6

T9

T8

Exp. Tank

PS1

PS

1/2 “3/4 “

T24

T25

T26T27T28

T29

T30

T31

T32

T33

T36

T34

T35

T37 T38

Needle Valve


D Pulsation Dampener

D

5/16 “

23 June 2019 6/43RP:1721 Oil Retention in gas lines

Refrigerant + Oil

Refrigerant

Oil

Sight Tube

Test Section


Valve

Ball Valve

Air Purge Valve


Controller

Liquid Pump

Check Valve

VCO Fitt ing

Pressure Switch

T13

Oil Separator


RefrigerantReceiver

Oil Receiver

Flow Meter

Development Length

DC - motor with VFD

P


Hot Water Return

Hot Water Supply




1/2 “

3/4 “

1-1/8 “

Flat Plate Heat


Oil Separator

P1

P2

T17

P4P5

M2

T11

T18

T19

T14

T15

T12

T22

P3


T21

T1 VFD

Exp. Tank

VFD M1

Flow Meter

P6 T16

Oil Separator


VFD

Water Reheater

with Buffer Tank



T20

Sub-cooler

T2

T3

T5

T6

T9

T8

Exp. Tank

PS1

PS

1/2 “3/4 “

T24

T25

T26T27T28

T29

T30

T31

T32

T33

T36

T34

T35

T37 T38

Needle Valve



D

5/16 “

Test Setup

23 June 2019 7RP:1721 Oil Retention in gas lines

Test Setup

Horizontal Test Sections

Vertical Test Sections

ChillersCondensers

Sub-cooler

Receiver Refrigerant Pump

Water Pump

8/36

Oil Pump

Oil Separators

23 June 2019 RP:1721 Oil Retention in gas lines

Development Length

Test Setup

Liquid Line

Refrigerant Mass Flow Meter

Evaporator

Water Heater Oil Mass Flow Meter

Oil LineOil Injection

9/36

Oil Line

Liquid Line


Water Pump

Agenda



• Test Setup

• Modifications

• Oil Injection



Test Matrix

11/4323 June 2019

Sr. No. Refrigerant Oil

Viscosity

[cSt]

Nominal Line

Diameter [mm]

Oil

Circulation

Rate [%] Mass Flow Rate

Test Section

Saturation

Temperature [C]

Test Section

Inlet

Temperature

[C]

10 20

40 64

10 20

40 64

10 20

40 64

10 20

40 64

1/3, 1, and 2 of Jacob's Limit 10 20

1/3, 1, 2 and 3x of Jacob's Limit 40 75







1/3, 1, 2 and 3x of Jacob's Limit

POE 68cSt 19.05 0.5, 3, 5 1/3, 1, 2 and 3x of Jacob's Limit

POE 100cSt 19.05

0.5, 3, 5

0.5, 3, 5 1/3, 1, 2 and 3x of Jacob's Limit

POE 170cSt 19.05 0.5, 3, 5 1/3, 1, 2 and 3x of Jacob's Limit

2 R410A

POE 32cSt12.70,

19.05,28.57

?12.70,

19.05,28.57

1 (Baseline) R134a

POE 32cSt 19.05

POE 68cSt12.70,

19.05,28.570.5, 3, 5

PAG/PVE

??

12.70,

19.05,28.570.5,3,5

AB

0.5, 3, 5

0.5, 3, 5


Refrigerant Only : Suction Line

12/4323 June 2019

Suction Line Test (Previous)

Can Achieve

Partially Achieve

Cannot Achieve

Sr. No.Refrigerant -

Lubricant

Nominal Line Diameter

[mm]

Ref. Mass Flow Rate

[kg/hr]

Oil Circulation Rate [kg/hr]

Test Section Saturation

Temperature [C]

Test Section Inlet

Temperature [C]

0.055 10 200.33 10 200.55 10 20

0.165 10 200.99 10 201.65 10 200.33 10 201.98 10 203.3 10 200.5 10 20 20 303 10 20 20 305 10 20 20 30

19.05

11

1 (Baseline) R134a - POE 32

33

66

100



13/4323 June 2019

Suction Line Test (Current)

Can Achieve

Partially Achieve

Sr. No.Refrigerant -

Lubricant

Nominal Line Diameter

[mm]

Ref. Mass Flow Rate

[kg/hr]

Oil Circulation Rate [kg/hr]

Test Section Saturation

Temperature [C]

Test Section Inlet

Temperature [C]

0.055 10 200.33 10 200.55 10 20

0.165 10 200.99 10 201.65 10 200.33 10 201.98 10 203.3 10 200.5 10 20 20 303 10 20 20 305 10 20 20 30

19.05

11

1 (Baseline) R134a - POE 32

33

66

100

‐Added bypass valve on the refrigeration loop


010

2030

4050

6070

Test Date : 13.Jun .2019 Refrig eran t : R134a Test: Suction L ine

Ref

riger

ant

Mas

s F

low

Rat

e [k

g/hr

]

Raw S igna l

Mov ing Ave rage o f 20 po ints

Se tpo int

-10

010

2030

4050

T im e [h r]

Tem

pera

ture

[°C

]

1 1.25 1.5 1.75 2

Refrige rant Temp a t Tes t Sec tion Inle t

Re frige rant Sa t Temp

Setpo int

Se tpo int

23 June 2019


66 kg/hr

33 kg/hr

11 kg/hr

RP:1721 Oil Retention in gas lines 14/43

23 June 2019

Pulsation – Refrigerant Pump

100 kg/hr

66 kg/hr

33 kg/hr

11 kg/hr

Filtered Signal

Raw Signal

RP:1721 Oil Retention in gas lines 15

050

100

150

Test Date : 09.Jan.2019 Refrigerant : R134a Test: Suction Line

Ref

riger

ant M

ass

Flo

w R

ate

[kg/

hr]

Raw Signal

Moving Average of 20 points

Setpoint

050

010

0015

0020

00

Time [hr]

Pre

ssur

e [k

Pa]

1.25 1.5 1.75 2 2.25

Ref. Pump Discharge Pressure

Ref. Suction Pressure

Test Section Pressure

23 June 2019 16/43

Pulsation – Diaphragm Pump (100 kg/h)

100 kg/hr


050

100

150

Test Date : 12.Jun.2019 Refrigerant : R134a Test: Suction Line

Ref

riger

ant M

ass

Flo

w R

ate

[kg/

hr]

Raw Signal


Setpoint

050

010

0015

0020

00

Time [hr]

Pre

ssur

e [k

Pa]

1 1.25 1.5 1.75 2




23 June 2019 17/43

Pulsation – Gear Pump (100 kg/h)

100 kg/hr


050

100

150


Ref

riger

ant M

ass

Flo

w R

ate

[kg/

hr]

Raw Signal


Setpoint

050

010

0015

0020

00

Time [hr]

Pre

ssur

e [k

Pa]

2.5 2.75 3 3.25




23 June 2019 18/43

Pulsation – Diaphragm Pump (66 kg/h)


050

100

150

Test Date : 12.Jun .2019 Refrig eran t : R134a Test: Suction L ine

Ref

riger

ant

Mas

s F

low

Rat

e [k

g/hr

]

Raw S igna l

M oving A verage o f 20 po ints

S etpo int

050

010

0015

0020

00

T im e [h r]

Pre

ssur

e [k

Pa]

4 .5 4.75 5

Ref. P um p D ischarge P ressure

Ref. S uction P ressure

Test S ection P ressure

23 June 2019 19/43

Pulsation – Gear Pump (66 kg/h)

66 kg/hr


050

100

150


Ref

riger

ant M

ass

Flo

w R

ate

[kg/

hr]

Raw Signal


Setpoint

050

015

0025

00

Time [hr]

Pre

ssur

e [k

Pa]

4 4.25 4.5




23 June 2019 20/43

Pulsation – Diaphragm Pump (33 kg/hr)

33 kg/hr


050

100

150

T est Date : 13.Ju n .2019 Refrig eran t : R134a T est: S u ctio n L in e

Ref

riger

ant

Mas

s F

low

Rat

e [k

g/hr

]

Raw S igna l

M oving A verage o f 20 po ints

S etpo int

050

010

0015

0020

00

T im e [h r]

Pre

ssur

e [k

Pa]

0 .75 1 1.25

Ref. P um p D ischarge P ressure

Ref. S uction P ressure

Test S ection P ressure

23 June 2019 21/43

Pulsation – Gear Pump (33 kg/hr)

33 kg/hr


23 June 2019 22

Liquid Refrigerant in Oil Separator

Problem• Liquid Refrigerant getting condensed in the oil

separator especially for the discharge line test

Solution• Insulate the vapor line between the vertical test

section and the oil separators• Add a heater in the oil collector and maintain a

temperature 10K > Sat. Temperature of the system to ensure all the refrigerant is evaporated

• If needed, connect the oil collector to the condenser inlet with a check valve

Oil Separators

Sight Tubes

Oil Collector

Condenser

Ref. Vapor Line


23 June 2019 23

Liquid Refrigerant in Oil Separator

Solution• Insulated the vapor line between the vertical test

section and the oil separators• Added a PID controlled heater along with

thermocouples in the oil collector • We maintain a temperature 10K > Sat. Temperature

of the system to ensure all the refrigerant is evaporated

• Added PID controlled heater along with thermocouple in oil collector as well

• Added pressure equalization line between the oil separator shell and the oil collector for the oil to flow under gravity

Oil Separators

Sight Tubes

Oil Collector Condenser

PressureEqualization Line


Agenda



• Test Setup

• Modifications

• Oil Injection



Refrigerant + Oil

Refrigerant

Oil

Sight Tube

Test Section


Valve

Ball Valve

Air Purge Valve


Controller

Liquid Pump

Check Valve

VCO Fitt ing

Pressure Switch

T13

Oil Separator


RefrigerantReceiver

Oil Receiver

Flow Meter

Development Length

DC - motor with VFD

P


Hot Water Return

Hot Water Supply




1/2 “

3/4 “

1-1/8 “

Flat Plate Heat


Oil Separator

P1

P2

T17

P4P5

M2

T11

T18

T19

T14

T15

T12

T22

P3


T21

T1 VFD

Exp. Tank

VFD M1

Flow Meter

P6 T16

Oil Separator


VFD

Water Reheater

with Buffer Tank



T20

Sub-cooler

T2

T3

T5

T6

T9

T8

Exp. Tank

PS1

PS

1/2 “3/4 “

T24

T25

T26T27T28

T29

T30

T31

T32

T33

T36

T34

T35

T37 T38

Needle Valve



D

5/16 “

25/43

Oil Injection


23 June 2019 26/43

Oil Return Issue – 33 kg/hr


23 June 2019 27/43

Oil Return Issue – 33 kg/hr


23 June 2019 28/43

Oil Return Solution

Test Section

Refrigerant Mass Flow Rate [kg/h]

Test Section Inside

Diameter [mm]

Mass Flux[kg/s-m2]

Jacob’s Limit

Nominal Pipe Size

Horizontal 33 16.9 40.8 1 3/4”

Vertical 33 10.9 97.8 2.4x 1/2”

Horizontal 11 16.9 13.6 0.3x 3/4”

Vertical 11 6.3 98.0 2.4x 5/16”


Refrigerant + Oil

Refrigerant

Oil

Sight Tube

Test Section


Valve

Ball Valve

Air Purge Valve


Controller

Liquid Pump

Check Valve

VCO Fitt ing

Pressure Switch

T13

Oil Separator


RefrigerantReceiver

Oil Receiver

Flow Meter

Development Length

DC - motor with VFD

P


Hot Water Return

Hot Water Supply




1/2 “

3/4 “

1-1/8 “

Flat Plate Heat


Oil Separator

P1

P2

T17

P4P5

M2

T11

T18

T19

T14

T15

T12

T22

P3


T21

T1 VFD

Exp. Tank

VFD M1

Flow Meter

P6 T16

Oil Separator


VFD

Water Reheater

with Buffer Tank



T20

Sub-cooler

T2

T3

T5

T6

T9

T8

Exp. Tank

PS1

PS

1/2 “3/4 “

T24

T25

T26T27T28

T29

T30

T31

T32

T33

T36

T34

T35

T37 T38

Needle Valve



D

5/16 “

29/43

Oil Return Issue


23 June 2019 30/43

Oil Injection Result : Test ID 33


23 June 2019 31/43



23 June 2019 32/43



23 June 2019 33/43



23 June 2019 34/43



23 June 2019 35/43



23 June 2019 36/43



37/43

Oil Injection Result


Sr. Description TestID 33 TestID 34 TestID 35 Unit

1 Refrigerant R134a R134a R134a

2 Oil POE‐32 POE‐32 POE‐32

3 Test Mode Suction Suction Suction

4 Horiztal Pipe Dia 16.9 16.9 16.9 mm

5 Vertical Pipe Dia 10.9 6.3 10.9 mm

6 Ref Flow Rate 21.1 8.76 30.31 kg/h

7 Oil Flow Rate 0.89 0.36 0.16 kg/h

8 Ref Mass Flux ‐ Horizontal 26.07 10.83 37.46 kg/m2‐s

9 Ref Mass Flux ‐ Vertical 62.53 78.09 89.86 kg/m2‐s

10 OCR 4.23 4.08 0.54 %

11 Oil Retention ‐ Horizontal 10.49 11.63 4.27 g/m

Ankit Sethi & Pega Hrnjak (2014) Oil retention and pressure drop of R1234yf and R134a with POE ISO 32 in suction lines, HVAC&R Research, 20:6, 703‐720

38/43

Test ID 33

Test ID 34

Test ID 35


Agenda



• Test Setup

• Modifications

• Oil Injection



23 June 2019 40/43

Oil Retention Measurement


Agenda


• Test Setup

• Test Matrix

• Shakedown Test Results (Oil Free)




Schedule

42/4323 June 2019

-

-

-

-

Proposed Schedule

Completed

In-progress

Planned


Year

Quarter

Quarterly Progress ReportFinal Report

Year 3

Apr - Jun 2017

Jul - Sep 2017

Oct - Dec 2017

Jan -Mar 2018

Apr - Jun 2018

Jul - Sep 2018

Oct - Dec 2018

Jan - Mar 2019

Apr - Jun 2019

Jul - Sep 2019

Oct - Dec 2019

Jan - Mar 2020

Task 1: Literature Review

Task 2: Development of Test Matrix

Task 3: Design and Construction of Experimental Setup

Task 4: Collect R134a/POE Baseline Data

Task 5: Collection of R410A data with first Lubricant

Task 6: Collect data with remaining Refrigerant-Oil Combinations

Task 7: Development of Model

Year 1 Year 2

Thank You.


oil return retentiontc0811.ashraetcs.org/documents/meeting-information...unitary split system gas...

Documents