Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Nucleate boiling heat transfer coefficients

of

pure halogenated refrigerants

Dongsoo Junga Youngil Kimb Younghwan Koa Kilhong Songa

Department of Mechanical Engineering Inha University Incheon 402-751 Republic of Korea

ThermalFlow Control Research Center Korea Institute of Science and Technology Seoul 130-650 Republic of Korea

Sudheer Nandi

(PhD)MTechMBA

Sustainable Energy Skorea

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Nucleate boiling heat transfer coefficients of pure halogenated

refrigerants

2

bull httpwwwsciencedirectcomsciencearticlepiiS0140700702000403

httpwwwyoutubecomwatchv=s-YmfZNKnlU

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Nucleate boiling heat transfer coefficients of pure halogenated

refrigerants

2

bull httpwwwsciencedirectcomsciencearticlepiiS0140700702000403

httpwwwyoutubecomwatchv=s-YmfZNKnlU

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 3

Qualitative classification flow regimes

MIT Department of Nuclear Science and Engineering

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 4

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 5

Heat transfer and flow regimes in a vertical heated channel (Thermal non‐equilibrium effec

ts have been neglected in sketching the bulk temperature)

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Abstract

bull Nucleate pool boiling heat transfer coefficients (HTCs) of HCFC123 CFC11 HCFC142b HFC134a CFC12HCFC22 HFC125

and HFC32 on a horizontal smooth tube of 190 mm outside diameter have been measured

bull The experimental apparatus was specially designed to accommodate high vapor pressure refrigerants such as HFC32 and

HFC125 with a sight glass

bull A cartridge heater was used to generate uniform heat flux on the tube Data were taken in the order of decreasing heat flux from

80 to 10 kW mminus2 with an interval of 10 kW m-2 in the pool of 7degC

bull Test results showed that HTCs of HFC125 and HFC32 were 50ndash70 higher than those of HCFC22 while HTCs of HCFC123 and

bull HFC134a were similar to those of CFC11 and CFC12 respectively

bull It was also found that nucleate boiling heat transfer correlations available in the literature were not good for certain alternative

refrigerants such as HFC32 and HCFC142b Hence a new correlation was developed by a regression analysis taking into account

the variation of the exponent to the heat flux term as a function of reduced pressure and some other properties

bull The new correlation showed a good agreement with all measured data including those of new refrigerants of significantly varying

vapor pressures with a mean deviation of less than 7

Keywords Heat transfer Mass transfer Nucleate Boiling Refrigerant Measurement

6

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 7

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 4

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 5

Heat transfer and flow regimes in a vertical heated channel (Thermal non‐equilibrium effec

ts have been neglected in sketching the bulk temperature)

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Abstract

bull Nucleate pool boiling heat transfer coefficients (HTCs) of HCFC123 CFC11 HCFC142b HFC134a CFC12HCFC22 HFC125

and HFC32 on a horizontal smooth tube of 190 mm outside diameter have been measured

bull The experimental apparatus was specially designed to accommodate high vapor pressure refrigerants such as HFC32 and

HFC125 with a sight glass

bull A cartridge heater was used to generate uniform heat flux on the tube Data were taken in the order of decreasing heat flux from

80 to 10 kW mminus2 with an interval of 10 kW m-2 in the pool of 7degC

bull Test results showed that HTCs of HFC125 and HFC32 were 50ndash70 higher than those of HCFC22 while HTCs of HCFC123 and

bull HFC134a were similar to those of CFC11 and CFC12 respectively

bull It was also found that nucleate boiling heat transfer correlations available in the literature were not good for certain alternative

refrigerants such as HFC32 and HCFC142b Hence a new correlation was developed by a regression analysis taking into account

the variation of the exponent to the heat flux term as a function of reduced pressure and some other properties

bull The new correlation showed a good agreement with all measured data including those of new refrigerants of significantly varying

vapor pressures with a mean deviation of less than 7

Keywords Heat transfer Mass transfer Nucleate Boiling Refrigerant Measurement

6

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 7

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 5

Heat transfer and flow regimes in a vertical heated channel (Thermal non‐equilibrium effec

ts have been neglected in sketching the bulk temperature)

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Abstract

bull Nucleate pool boiling heat transfer coefficients (HTCs) of HCFC123 CFC11 HCFC142b HFC134a CFC12HCFC22 HFC125

and HFC32 on a horizontal smooth tube of 190 mm outside diameter have been measured

bull The experimental apparatus was specially designed to accommodate high vapor pressure refrigerants such as HFC32 and

HFC125 with a sight glass

bull A cartridge heater was used to generate uniform heat flux on the tube Data were taken in the order of decreasing heat flux from

80 to 10 kW mminus2 with an interval of 10 kW m-2 in the pool of 7degC

bull Test results showed that HTCs of HFC125 and HFC32 were 50ndash70 higher than those of HCFC22 while HTCs of HCFC123 and

bull HFC134a were similar to those of CFC11 and CFC12 respectively

bull It was also found that nucleate boiling heat transfer correlations available in the literature were not good for certain alternative

refrigerants such as HFC32 and HCFC142b Hence a new correlation was developed by a regression analysis taking into account

the variation of the exponent to the heat flux term as a function of reduced pressure and some other properties

bull The new correlation showed a good agreement with all measured data including those of new refrigerants of significantly varying

vapor pressures with a mean deviation of less than 7

Keywords Heat transfer Mass transfer Nucleate Boiling Refrigerant Measurement

6

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 7

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Abstract

bull Nucleate pool boiling heat transfer coefficients (HTCs) of HCFC123 CFC11 HCFC142b HFC134a CFC12HCFC22 HFC125

and HFC32 on a horizontal smooth tube of 190 mm outside diameter have been measured

bull The experimental apparatus was specially designed to accommodate high vapor pressure refrigerants such as HFC32 and

HFC125 with a sight glass

bull A cartridge heater was used to generate uniform heat flux on the tube Data were taken in the order of decreasing heat flux from

80 to 10 kW mminus2 with an interval of 10 kW m-2 in the pool of 7degC

bull Test results showed that HTCs of HFC125 and HFC32 were 50ndash70 higher than those of HCFC22 while HTCs of HCFC123 and

bull HFC134a were similar to those of CFC11 and CFC12 respectively

bull It was also found that nucleate boiling heat transfer correlations available in the literature were not good for certain alternative

refrigerants such as HFC32 and HCFC142b Hence a new correlation was developed by a regression analysis taking into account

the variation of the exponent to the heat flux term as a function of reduced pressure and some other properties

bull The new correlation showed a good agreement with all measured data including those of new refrigerants of significantly varying

vapor pressures with a mean deviation of less than 7

Keywords Heat transfer Mass transfer Nucleate Boiling Refrigerant Measurement

6

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 7

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 7

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 8

Experimental apparatus

shows a schematic diagram of the experimental apparatus for nucleate boiling heat transfer that

can be used to take measurements up to 2500 Kpa

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Manufacture of the tube

9

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

In this study a cartridge heater was used to generate uniform heat flux on the surface of the heat transfer tube The uniformity of the heater

was thoroughly checked before its use and it was inserted into the center hole of 95 mm diameter which was machined by a gun

drill as mentioned earlier And then a paste of high thermal conductivity was applied between the inner surface of the hole and cartridge

heater and the heater was pushed through the hole tightly

Finally the left end of the tube was capped with a Bakelite piece and epoxy for insulation and soldered with a copper cap for sealing and

the other end with the heaterrsquos electrical connections was sealed with epoxy and a nylon cap as shown in Fig 2(b)

10

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

The experimental procedure for a given refrigerant was as

follows1 Nitrogen was charged to the refrigerant loop up to 1500 kPa with some halogenated refrigerants to check with a

halogen detector if there was any leak

2 A vacuum pump was turned on few hours to evacuate the system thoroughly and the refrigerant was charged to the

system up to 30 mm higher than the top of the heat transfer tube

3 The liquid was heated for 2 h by supplying power to the cartridge heater maintaining the heat flux of 60 kW m2 on

the heat transfer tube and the vapor was vented a few times for degassing which was especially important for low

pressure refrigerants that might have trapped some air within

4 After 1 h power to the cartridge heater was initiated and the heat flux was increased to 80 kW m2 gradually And

data were taken under steady state at 7 C from 80 to 10 kW m2 with an interval of 10 kW m2 in the order of decreasing

heat flux to avoid a hysteresis effect

5 Refrigerant was changed and the same procedures of (1ndash4) were repeated after the surface was cleaned as described

earlier

11

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 12

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 13

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 14

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 15

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 16

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

Comparison of the present data with a new

correlation for all pure refrigerants

17

Heat transfer coefficients vs heat flux on a logarithmic plot

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

ConclusionsIn this study nucleate boiling heat transfer coefficients (HTCs) of eight pure halogenated refrigerants of HCFC123 CFC11 HCFC142b

HFC134a CFC12 HC FC22 HFC125 and HFC32 were measured at the liquid temperature of 7 C on a plain tube of 190 mm outside diameter

All data were taken from 80 to 10 kW m2 with an interval of 10 kWm2 in the decreasing order of heat flux Based upon the test results and cor

relation development following conclusions can be drawn

(1) At the same pool temperature refrigerants with higher vapor pressures showed higher nucleate boiling HTCs consistently This was due to

the fact that the wall superheat required to activate given size cavities became smaller as pressure increased

(2) Stephan and Abdelsalamrsquos correlation under predicted the present data by 175 while Cooperrsquos over predicted them by 151 Stephan

and Abdelsalamrsquos correlation under predicted the data of HFC32 by 48 while Cooperrsquos over predicted the data of HCFC142b by 44

(3) Some dimensionless groups affecting nucleate boiling heat transfer were identified and they were correlated by a regression analysis to

yield a new correlation valid for all halogenated refrigerants tested Thus developed correlation predicted the present data within 7 deviation

for all refrigerants including HFC32 and HCFC142b The new correlation takes into account that the exponent to the heat flux term

varies significantly among fluids and also is a strong function of reduced pressure

18

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ

References[1] Molina MJ Rowland FS Stratospheric sink for chlorofluoromethane chlorine atom catalyzed destruction of ozone Nature 19742

49810ndash2

[2] United Nations Environment Programme Montreal protocol on substances that deplete the ozone layer Final Act 1989

[3] Air-conditioning and Refrigeration Institute R22 and R502 alternative refrigerants evaluation program Arlington (VA USA) 1992

ndash1997

[4] Cavallini A Working fluids for mechanical refrigerationInt J Refrigeration 199619(8)485ndash96

[5] Jung D Kim C Song K Lee J Nucleate boiling heat transfer coefficients of pure refrigerants Proc 11th Int Heat Transfer Conf 199

82443ndash7

[6] Thome JR Boiling of new refrigerants a state-of-the-artreview Int J Refrigeration 199619(7)435ndash57

[7] Gorenflo D State of the art in pool boiling heat transfer of new refrigerants Int J Refrigeration 2001246ndash14

[8] Jung D Kim C Cho S Song K Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 a

nd CFC12 Int J Refrigeration 199922(7)548ndash57

[9] Webb RL Principles of enhanced heat transfer New York John Wiley amp Sons 1994 p 293ndash4

[10] Kline SJ McClintock FA Describing uncertainties in single- sample experimentsMechanical Engineers 1953753ndash9

[11] McLinden MO Klein SA Lemmon EW Peskin AP NIST thermodynamic and transport properties of refrigerants and refrigerant

mixturesmdashREFPROP version 60 1998

[12] Webb RL Pais C Nucleate pool boiling data for five refrigerants on plain integral-fin and enhanced tube geometries

Int J Heat Mass Transfer 199235(8)1893ndash904

[13] Stephan K Abdelsalam M Heat transfer correlations for natural convection boiling Int J Heat Mass Transfer 1980 2373ndash

87

[14] Cooper MG Heat flow rates in saturated nucleate pool boilingmdasha wide-ranging examination using reduced properties

In Advances in Heat Transfer vol 16 Academic Press 1984 p 157ndash239

[15] Rohsenow WM Hartnett JP Ganic EN Handbook of heat transfer fundamentals 2nd ed McGraw-Hill 1985 p 12ndash22

[16] Incropera FP DeWitt DP Fundamentals of heat and mass transfer 4th ed New York John Wiley amp Sons 1994 p 536ndash7

[17] Cooper MG Correlations for nucleate boilingmdashformulation using reduced properties Physico Chemical Hydrodynamics

19823(2)89ndash111

19

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening

Thermal Energy Conversion Control Lab Chonbuk NatrsquoI Univ 20

Thank you for listening