The effect of CuOwater nanofluids and biomaterial wick on loop heat pipe performance.
Advanced Materials Research Vols. 875-877 (2014) pp 356-361
Online available since 2014/Feb/27 at www.scientific.net
© (2014) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/AMR.875-877.356
The Effect of CuO-water Nanofluid and Biomaterial Wick
On Loop Heat Pipe Performance
Nandy Putra1, Wayan Nata Septiadi1, Rosari Saleh2, Raldi Artono Koestoer1,
Suhendro Purbo Prakoso2
1
Heat Transfer Laboratory, Department of Mechanical Engineering University of Indonesia
Kampus Baru UI-Depok, 16424 Indonesia
2
Department of Physics University of Indonesia
nandyputra@eng.ui.ac.id
Keywords: loop heat pipe, wick, biomaterial, nano fluid.
Abstract The determinants of heat pipe performances are its wick and working fluid, instead of
controlled by the material, dimension, and the shape of heat pipe. This study aimed to determine the
effect of using nano-fluid on the performance of Loop heat pipes (LHP) with CuO-water nanofluid
that using biomaterials wick. LHP was made of 8 mm diameter copper pipe, with the diameter of
evaporator and the condenser was 20 mm respectively and the length of the heat pipe was 100 mm.
The wick was made of biomaterials Collaria Tabulate and the working fluid was CuO-water
nanofluids where the CuO nanoparticles were synthesized by sol-gel method. The characteristic of the
Tabulate Collaria biomaterial as a wick in LHP was also investigated in this experiment. The results
of the experiments showed that the temperature differences between the evaporator and condenser
sections with the biomaterial wick and CuO-water nanofluid were less than those using pure water.
These results make the biomaterial (Collar) and nanofluids are attractive both as wick and working
fluid in LHP technology.
Introduction
Materials with porous structures or porous media, have been giving massive advantages in developing
heat pipe as one of heat exchangers especially for the evaporator and the condenser. The permeability
of porous media has importance in some cases concerning fluid flows to these media, whether with
macro structures, the combination of both macro and micro structures, or with nano structures as well
[1]. Electronic cooler beneficiation with space two-phase and porous media as capillary pump in
controlling the circulation of working fluid in cooler is ever more required to address thermal
problems in electronic devices and other advanced technologies [2]. Heat pipe is the technology
transferring heat which applies these principles. Heat pipe is made of the pipe with certain size and
contains specific fluids for transferring the heat from evaporator to condenser. Moreover, porous
media, so-called-wicks, are provided in these technologies as the paths or channels for the fluid
flowing back to evaporator [3-6].
There are many kind of heat pipes such as straight heat pipe, L-type heat pipe, heat pipe with phase
change material (PCM), loop heat pipe (LHP), micro-type heat pipe, flat-type heat pipe, and heat pipe
in liquid-block and thermoelectric [7-11]. The application of heat pipe in industrial and electric
technologies has been applied progressively, such as for heat-exhausted recovery, air pre-heater and
the utilization of heat exhaust to boiler which certainly succeed [12]. Heat pipe has been used recently
due to its superiorities, such as the short-cycle of heat transfer, the dense of its dimension, the high
level of heat transfer coefficient, and also it is no necessary to acquire additional energy because the
fluid circulation occur naturally [12]. Therefore, many of industrial fields and researchers find it is
important to understand characteristics problems of this heat pipe.
The determinant of the heat pipe performances are wick and working fluid, instead of controlled by
the material, dimension, and shape of the heat pipe [13]. The wick has important role in working fluid
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,
www.ttp.net. (ID: 152.118.24.10, University of Indonesia, Depok, Indonesia-17/07/14,06:07:12)
Advanced Materials Research Vols. 875-877
357
circulation, primarily in process of water condensate flow back to evaporator sites. Wick in heat pipe
is used for capillary structural or arteries as the return-flow tunnels of working fluids from condenser
to evaporator through adiabatic section. Wick is a part of heat pipe whose function is to circulate fluid
from condenser to evaporator. Hence, wick plays vital roles in both conventional heat pipe and LHP.
There are some types of wick in heat pipe including screen mesh, sintered powder, groove, and wire.
All of those were made of metal, composite, and ceramics [14-20].
Many studies have been accomplished relating with wick. Jinwang Li et. al examined the capillary
pump of sintered powder wick and found that the capillarity of the wick increased along with the rise
of porous value of wicks, to name but a few [14]. Also, K.C Leong et. al [21] studied the
characterization of wick heat pipe which was made from sintered powder. This characterization was
influenced by sintering temperature (800oC dan 1000oC) and sintering time to the porous of wick.
D.K. Mishra et.al , K.J Zan et. al, Yong Tang et. al, Brian Holley et al and Marcelo Lago et al [22-24]
have also done the assessment and characterization of the structure of porous media.
Recently, nano fluid is an alternative as a working fluid that is widely used in heat pipe
applications. N Putra et al, S.W Kang et. al [25, 26], Zhenhua Liu et. al [27, 28], Kyu Hyung Do et. al
[29] and R. Saleh et. al [30] who have also been applying nano fluid in the heat pipe. Their results
showed that the application of nano-fluid in heat pipe could improve the performance of heat pipes.
This study aimed to determine the effect of using low concentration CuO-water nano fluid on the
performance of LHP with biomaterial as a wick.
Research Methodology
LHP was made of copper pipe with diameter of 8 mm, with the evaporator and the condenser has a
diameter of 20 mm and the overall length of 100 mm. Wick is made of biomaterials Tabulate Collaria
that previously tested by Jinwang Li et al.’s method for measuring the capillary pumping parameter of
a porous wick. Measurements have been done for several biomaterial such as Tabulate, Massive,
Sintered, Foliose and Branching. The capillary pumping performance of the sample Tabulate was the
best, followed by Massive, Sintered, Foliose and Branching [31] .
CuO-water nanofluid was made with dispersion CuO nanoparticles ± 17 nm in water as based fluid
and then sonificated using ultrasonic processor. The CuO nanoparticles was synthesized by sol-gel
method. CuSO4.5H2O, NaOH, DI-water and ethanol were used as the precursor on the synthesis
process. The requisite amount of CuSO4.5H2O and NaOH were dispersed in 200 ml and 300 ml
DI-water, respectively. The NaOH solution was added slowly to CuSO4.5H2O solution until the pH of
mixed solution reach 13. On the same time, mixed solution was stirred continously on the hot plate
magnetic stirrer for 5 hour with the temperature hot plate is set to 250oC. Then the precipitate was
washed by DI-water and ethanol to prevent the by product reaction. The dark brown of CuO
nanoparticles powder was obtained after the precipitate was dried at temperature 125oC for 8 hour.
Figure 1 shows SEM photograph and EDX test of CuO nano particles. From the figure can be seen
that CuO particles was in nano-sized and Cu content was 58.02%, O 32.27%, and there are elements
of C 9.71%. In this study, nano-fluid CuO water was made in the 0.025%, 0.05%, and 0.075% volume
fraction. Then nano fluid is charged into the LHP with 60% loading fluid.
Figure1. SEM Photograph and EDX CuO nano particle
358
Material Research and Applications
Figure 2 shows the schematic of the LHP performance test. As a heat source on the evaporator, the
electric heater was attached which was controlled by DC power supply, while heat removal in
condenser was brought about by circulation of the cooling water through a coaxial liquid cooling heat
exchanger. A recirculating thermostatic bath was used to provide a continuous flow of cooling water
in the heat exchanger; the coolant tank’s temperature stability was controlled with an accuracy rate of
± 0.5oC and was set at 25oC. The temperature was measured at several sections on evaporator,
condenser and also the adiabatic, using thermocouple type-K with an accuracy rate of ± 0.1oC
connected to cDAQ-NI. To avoid heat loss to other parts of condenser, the LHP was insulated with
polyurethane.
Figure 2. Experimental set-up
Result and Discussion
Figure 3 (a) and 3 (b) show the temperature distribution of the biomaterial wick LHP with variation of
volume concentration and heat source respectively. The temperature decreased from the evaporator,
but the trajectory of steam at the condenser has a slight increase again in the fluid path. Improved
loading visible has increases the temperature in the evaporator but at different loading levels; the
temperature distribution of LHP has the same trend for each volume concentration. In figure 3 can be
seen that CuO-water nano fluid 0.075% fraction volume has the best heat absorption, so the
temperature at the evaporator to be the lowest. This is because at higher concentrations, the heat
transfer through contact between surfaces becomes greater so the ability of nano-fluid to absorb and
transfer the heat also becomes faster.
The presence of CuO nano-particles in the base fluid results in particles dispersed in the fluid so it
will affect the viscosity of the working fluid which will affect heat transfer coefficient of the working
fluid. Nano fluid also affects the flow rate of the condensate from the condenser into the evaporator
where it is influenced by the addition of porosity and capillarity wick, the viscosity of the fluid is also
crucial. This will prevent dryness (dry out) on the evaporator due to the inability of the liquid
condensate return.
Entrainment restriction which limits the maximum heat that can be absorbed by a heat pipe
depends on the ability of the capillarity of the wick that is capable of forming the sufficient of
capillary pressure to pump or drain condensate to the evaporator. The existence of wick with great
capillarity is also function as a separate track that is used to limit the mixing of vapor with liquid.
Advanced Materials Research Vols. 875-877
359
Figure 3. (a)Temperature distribution of working fluids water and nanofluids with biomaterial wick,
(b) Temperature distribution of working fluids CuO-water nanofluids 0.75%
with biomaterial wick
Figure. 4 Distribution temperature of LHPs with sintered powder wick, biomaterial wick and without
wick, respectively
The performances of LHP with biomaterials wick in comparison with sintered powder wick and
without wick are shown in figure 4. It can be seen that the temperature in the evaporator of LHP with
biomaterial was the lowest due to the structural of biomaterial is more homogeneous than sintered
powder. Meanwhile, for the LHP without wick or wick thermosipon has the absence of a capillary
pump between the trajectory and the vapor line. It was because the condensate which return from the
condenser to the evaporator was inhibited by the steam flowing from the evaporator to the condenser.
The structures of biomaterial may make smaller contact angle with the liquid and the wick capillary
pressure tend to increase as the mass flow rate of condensate so that the performance of the LHP will
more excellent.
Figure 5 is the result of EDX testing of wick biomaterials before and after using CuO-water nano
fluids. CuO-Water nano fluid charged in LHP had changed the surface of wick, where it can be seen
cleary in the wick EDX test before and after experiment that using CuO-water nano fluid. From the
Fig 5b can be seen that the elements of Cu had coated the surface of the wick. However, the Cu
coating on the surface of the wick is only11.23%., which was not so significant.
360
Material Research and Applications
(a)
(b)
Figure 5. Wick condition (a) before and (b) after experiment
Conclusion
It can be concluded that the use of CuO-water nano fluid and biomaterials wick can improve the
performance of loop heat pipe as compared to using a water-based fluid and sintered powder wick.
Evaporator temperature at 10 watts was 43 oC, it was 17.3% lower than using water fluid. The values
of small porosity will increase the capillarity that will increase the condensate flow rate into the
evaporator. Wick surface had been coating by CuO-water nano fluid but not so much.
Acknowledgement
The authors would like to thank the DRPM University of Indonesia for funding this research through
Hibah Riset Utama UI 2012.
Literature References
[1]. Yu, Boming., and Ping Cheng : International Journal of Heat and Mass Transfer vol 45 (2002), p.
2983-2993
[2]. Kaya, Tarik., and John Goldak : International Journal of Heat and Mass Transfer Vol 49 (2006), p.
3211-3220
[3]. Reay, David & Peter Kew., Heat Pipe, Theory, Design and Applications, 5th Edition, USA, 2006.
[4]. Leonard L, Vasiliev : Applied Thermal Engineering 25 (2005), p.1-19
[5]. Harris, James R., Modeling, Designing, Fabricating and Testing of Channel Panel Flat Plate
Heat Pipe. Utah State University, (2008), p.1-6
[6]. Ochterbeck, Jay M., Heat Pipe. Departement of Mechanical Engineering Clemson University,
pp.1182-1229.
[7]. Nandy Putra, Yanuar, Ferdiansyah N. Iskandar : Experimental Thermal and Fluid Science 35
(2011), p. 1274–1281
[8]. Ying-CheWeng, Hung-Pin Cho, Chih-Chung Chang, Sih-Li Chen : Applied Energy 88 (2011), p.
1825–1833
[9]. Jung-Chang Wang : International Journal of Thermal Sciences 50 (2011), p. 97-105
[10]. Leonid Vasilieva, David Lossouarn, Cyril Romestant, Alain Alexandre, Yves Bertin,
YauheniPiatsiushyk, Vladimir Romanenkov : International Journal of Heat and Mass Transfer
52 (2009), p. 301–308
[11]. L.L. Vasiliev: Applied Thermal Engineering 28 (2008), p. 266–273
Advanced Materials Research Vols. 875-877
361
[12]. Leonard L. Vasiliev: Applied Thermal Engineering 25 (2005) p. 1–19
[13]. Weibel, Justin A., Suresh V Garimella., and Mark T North: International Journal of Heat and
Mass Transfer vol 53 (2010), p. 4202-4215
[14]. Jinwang Li, Yong Zou, Lin Cheng : Experimental Thermal and Fluid Science 34 (2010), p.
1403–1408.
[15]. R. Kempers, A. J. Robinson, D. Ewing, C. Y. Ching : International Journal of Heat and Mass
Transfer 51 (2008), p. 6039–6046.
[16]. Nandy Putra, Wayan Nata Septiadi, Haolia Rahman, Ridho Irwansyah : Experimental Thermal
and Fluid Science, 40 (2012), p. 10-17
[17]. Frédéric Lefèvre, Jean-Baptiste Conrardy, Martin Raynaud, Jocelyn Bonjour : Applied Thermal
Engineering (2011), p. 1-8.
[18]. Yu-Wei Chang, Chiao-Hung Cheng, Jung-Chang Wang, Sih-Li Chen : Energy Conversion and
Management 49 (2008), pp. 3398–3404
[19]. Kyu Hyung Do, Hyo Jun Ha, Seok Pil Jang : International Journal of Heat and Mass Transfer 53
(2010) p. 5888–5894.
[20]. Nandy Putra, Saputra, M. Iqbal Bimo, Ridho Irwansyah, Wayan Nata S. Experimental Study on
Sintered Powder Wick Loop Heat Pipe. The 4th International Meeting of Advances in
Thermofluids, Melaka, Malaysia, 3rd - 4th October, (2011).
[21]. K.C. Leong and C.Y. Liu : Journal of Porous Materials 4 (1997), p. 303–308
[22]. D.K. Mishra, T.T. Saravanan, G.P. Khanra, S. Girikumar, S.C. Sharma, K. Sreekumar, P.P.
Sinha.: Advanced Powder Technology 21 (2010), p. 658–662.
[23]. K.J. Zan, C.J. Zan, Y.M. Chen, and S.J. Wu : Heat Transfer—Asian Research, 33 (8), 2004
[24]. Yong Tang, Daxiang Deng, Longsheng Lu, Minqiang Pan, Qinghui Wang : Experimental
Thermal and Fluid Science 34 (2010), p. 190–196
[25]. S.W. Kang, W.C. Wei, S.H. Tsai, C.C. Huang : Applied Thermal Engineering 29 (5–6) (2009),
p. 973–979.
[26]. S.W. Kang, W.C. Wei, S.H. Tsai, S.Y. Yang : Applied Thermal Engineering 26 (17–18) (2006),
p. 2377–2382
[27]. Zhen-Hua Liu, Yuan-Yang Li. Ran Bao : International Journal of Thermal Sciences 49 (2010),
p. 1680-1687
[28]. ZhenHua Liu, QunZhi Zhu. : Energy Conversion and Management 52 (2011) p. 292–300.
[29]. Kyu Hyung Do, Hyo Jun Ha, Seok Pil Jang : International Journal of Heat and Mass Transfer 53
(2010), p. 5888–5894.
[30]. Rosari Saleh, Nandy Putra, Suhendro Purbo Prakoso, Wayan Nata Septiadi, Experimental
investigation of thermal conductivity and heat pipe thermal performance of ZnO nanofluids,
International Journal of Thermal Sciences, (2012) In Press.
[31]. Nandy Putra, Rosari Saleh, Wayan Nata Septiadi, A. Okta D, Zein Hamid, Thermal
performance of nanofluids in biomaterial wick loop heat pipes, submitted to International
Journal of Thermal Sciences
Material Research and Applications
10.4028/www.scientific.net/AMR.875-877
The Effect of CuO-Water Nanofluid and Biomaterial Wick on Loop Heat Pipe Performance
10.4028/www.scientific.net/AMR.875-877.356
Online available since 2014/Feb/27 at www.scientific.net
© (2014) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/AMR.875-877.356
The Effect of CuO-water Nanofluid and Biomaterial Wick
On Loop Heat Pipe Performance
Nandy Putra1, Wayan Nata Septiadi1, Rosari Saleh2, Raldi Artono Koestoer1,
Suhendro Purbo Prakoso2
1
Heat Transfer Laboratory, Department of Mechanical Engineering University of Indonesia
Kampus Baru UI-Depok, 16424 Indonesia
2
Department of Physics University of Indonesia
nandyputra@eng.ui.ac.id
Keywords: loop heat pipe, wick, biomaterial, nano fluid.
Abstract The determinants of heat pipe performances are its wick and working fluid, instead of
controlled by the material, dimension, and the shape of heat pipe. This study aimed to determine the
effect of using nano-fluid on the performance of Loop heat pipes (LHP) with CuO-water nanofluid
that using biomaterials wick. LHP was made of 8 mm diameter copper pipe, with the diameter of
evaporator and the condenser was 20 mm respectively and the length of the heat pipe was 100 mm.
The wick was made of biomaterials Collaria Tabulate and the working fluid was CuO-water
nanofluids where the CuO nanoparticles were synthesized by sol-gel method. The characteristic of the
Tabulate Collaria biomaterial as a wick in LHP was also investigated in this experiment. The results
of the experiments showed that the temperature differences between the evaporator and condenser
sections with the biomaterial wick and CuO-water nanofluid were less than those using pure water.
These results make the biomaterial (Collar) and nanofluids are attractive both as wick and working
fluid in LHP technology.
Introduction
Materials with porous structures or porous media, have been giving massive advantages in developing
heat pipe as one of heat exchangers especially for the evaporator and the condenser. The permeability
of porous media has importance in some cases concerning fluid flows to these media, whether with
macro structures, the combination of both macro and micro structures, or with nano structures as well
[1]. Electronic cooler beneficiation with space two-phase and porous media as capillary pump in
controlling the circulation of working fluid in cooler is ever more required to address thermal
problems in electronic devices and other advanced technologies [2]. Heat pipe is the technology
transferring heat which applies these principles. Heat pipe is made of the pipe with certain size and
contains specific fluids for transferring the heat from evaporator to condenser. Moreover, porous
media, so-called-wicks, are provided in these technologies as the paths or channels for the fluid
flowing back to evaporator [3-6].
There are many kind of heat pipes such as straight heat pipe, L-type heat pipe, heat pipe with phase
change material (PCM), loop heat pipe (LHP), micro-type heat pipe, flat-type heat pipe, and heat pipe
in liquid-block and thermoelectric [7-11]. The application of heat pipe in industrial and electric
technologies has been applied progressively, such as for heat-exhausted recovery, air pre-heater and
the utilization of heat exhaust to boiler which certainly succeed [12]. Heat pipe has been used recently
due to its superiorities, such as the short-cycle of heat transfer, the dense of its dimension, the high
level of heat transfer coefficient, and also it is no necessary to acquire additional energy because the
fluid circulation occur naturally [12]. Therefore, many of industrial fields and researchers find it is
important to understand characteristics problems of this heat pipe.
The determinant of the heat pipe performances are wick and working fluid, instead of controlled by
the material, dimension, and shape of the heat pipe [13]. The wick has important role in working fluid
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,
www.ttp.net. (ID: 152.118.24.10, University of Indonesia, Depok, Indonesia-17/07/14,06:07:12)
Advanced Materials Research Vols. 875-877
357
circulation, primarily in process of water condensate flow back to evaporator sites. Wick in heat pipe
is used for capillary structural or arteries as the return-flow tunnels of working fluids from condenser
to evaporator through adiabatic section. Wick is a part of heat pipe whose function is to circulate fluid
from condenser to evaporator. Hence, wick plays vital roles in both conventional heat pipe and LHP.
There are some types of wick in heat pipe including screen mesh, sintered powder, groove, and wire.
All of those were made of metal, composite, and ceramics [14-20].
Many studies have been accomplished relating with wick. Jinwang Li et. al examined the capillary
pump of sintered powder wick and found that the capillarity of the wick increased along with the rise
of porous value of wicks, to name but a few [14]. Also, K.C Leong et. al [21] studied the
characterization of wick heat pipe which was made from sintered powder. This characterization was
influenced by sintering temperature (800oC dan 1000oC) and sintering time to the porous of wick.
D.K. Mishra et.al , K.J Zan et. al, Yong Tang et. al, Brian Holley et al and Marcelo Lago et al [22-24]
have also done the assessment and characterization of the structure of porous media.
Recently, nano fluid is an alternative as a working fluid that is widely used in heat pipe
applications. N Putra et al, S.W Kang et. al [25, 26], Zhenhua Liu et. al [27, 28], Kyu Hyung Do et. al
[29] and R. Saleh et. al [30] who have also been applying nano fluid in the heat pipe. Their results
showed that the application of nano-fluid in heat pipe could improve the performance of heat pipes.
This study aimed to determine the effect of using low concentration CuO-water nano fluid on the
performance of LHP with biomaterial as a wick.
Research Methodology
LHP was made of copper pipe with diameter of 8 mm, with the evaporator and the condenser has a
diameter of 20 mm and the overall length of 100 mm. Wick is made of biomaterials Tabulate Collaria
that previously tested by Jinwang Li et al.’s method for measuring the capillary pumping parameter of
a porous wick. Measurements have been done for several biomaterial such as Tabulate, Massive,
Sintered, Foliose and Branching. The capillary pumping performance of the sample Tabulate was the
best, followed by Massive, Sintered, Foliose and Branching [31] .
CuO-water nanofluid was made with dispersion CuO nanoparticles ± 17 nm in water as based fluid
and then sonificated using ultrasonic processor. The CuO nanoparticles was synthesized by sol-gel
method. CuSO4.5H2O, NaOH, DI-water and ethanol were used as the precursor on the synthesis
process. The requisite amount of CuSO4.5H2O and NaOH were dispersed in 200 ml and 300 ml
DI-water, respectively. The NaOH solution was added slowly to CuSO4.5H2O solution until the pH of
mixed solution reach 13. On the same time, mixed solution was stirred continously on the hot plate
magnetic stirrer for 5 hour with the temperature hot plate is set to 250oC. Then the precipitate was
washed by DI-water and ethanol to prevent the by product reaction. The dark brown of CuO
nanoparticles powder was obtained after the precipitate was dried at temperature 125oC for 8 hour.
Figure 1 shows SEM photograph and EDX test of CuO nano particles. From the figure can be seen
that CuO particles was in nano-sized and Cu content was 58.02%, O 32.27%, and there are elements
of C 9.71%. In this study, nano-fluid CuO water was made in the 0.025%, 0.05%, and 0.075% volume
fraction. Then nano fluid is charged into the LHP with 60% loading fluid.
Figure1. SEM Photograph and EDX CuO nano particle
358
Material Research and Applications
Figure 2 shows the schematic of the LHP performance test. As a heat source on the evaporator, the
electric heater was attached which was controlled by DC power supply, while heat removal in
condenser was brought about by circulation of the cooling water through a coaxial liquid cooling heat
exchanger. A recirculating thermostatic bath was used to provide a continuous flow of cooling water
in the heat exchanger; the coolant tank’s temperature stability was controlled with an accuracy rate of
± 0.5oC and was set at 25oC. The temperature was measured at several sections on evaporator,
condenser and also the adiabatic, using thermocouple type-K with an accuracy rate of ± 0.1oC
connected to cDAQ-NI. To avoid heat loss to other parts of condenser, the LHP was insulated with
polyurethane.
Figure 2. Experimental set-up
Result and Discussion
Figure 3 (a) and 3 (b) show the temperature distribution of the biomaterial wick LHP with variation of
volume concentration and heat source respectively. The temperature decreased from the evaporator,
but the trajectory of steam at the condenser has a slight increase again in the fluid path. Improved
loading visible has increases the temperature in the evaporator but at different loading levels; the
temperature distribution of LHP has the same trend for each volume concentration. In figure 3 can be
seen that CuO-water nano fluid 0.075% fraction volume has the best heat absorption, so the
temperature at the evaporator to be the lowest. This is because at higher concentrations, the heat
transfer through contact between surfaces becomes greater so the ability of nano-fluid to absorb and
transfer the heat also becomes faster.
The presence of CuO nano-particles in the base fluid results in particles dispersed in the fluid so it
will affect the viscosity of the working fluid which will affect heat transfer coefficient of the working
fluid. Nano fluid also affects the flow rate of the condensate from the condenser into the evaporator
where it is influenced by the addition of porosity and capillarity wick, the viscosity of the fluid is also
crucial. This will prevent dryness (dry out) on the evaporator due to the inability of the liquid
condensate return.
Entrainment restriction which limits the maximum heat that can be absorbed by a heat pipe
depends on the ability of the capillarity of the wick that is capable of forming the sufficient of
capillary pressure to pump or drain condensate to the evaporator. The existence of wick with great
capillarity is also function as a separate track that is used to limit the mixing of vapor with liquid.
Advanced Materials Research Vols. 875-877
359
Figure 3. (a)Temperature distribution of working fluids water and nanofluids with biomaterial wick,
(b) Temperature distribution of working fluids CuO-water nanofluids 0.75%
with biomaterial wick
Figure. 4 Distribution temperature of LHPs with sintered powder wick, biomaterial wick and without
wick, respectively
The performances of LHP with biomaterials wick in comparison with sintered powder wick and
without wick are shown in figure 4. It can be seen that the temperature in the evaporator of LHP with
biomaterial was the lowest due to the structural of biomaterial is more homogeneous than sintered
powder. Meanwhile, for the LHP without wick or wick thermosipon has the absence of a capillary
pump between the trajectory and the vapor line. It was because the condensate which return from the
condenser to the evaporator was inhibited by the steam flowing from the evaporator to the condenser.
The structures of biomaterial may make smaller contact angle with the liquid and the wick capillary
pressure tend to increase as the mass flow rate of condensate so that the performance of the LHP will
more excellent.
Figure 5 is the result of EDX testing of wick biomaterials before and after using CuO-water nano
fluids. CuO-Water nano fluid charged in LHP had changed the surface of wick, where it can be seen
cleary in the wick EDX test before and after experiment that using CuO-water nano fluid. From the
Fig 5b can be seen that the elements of Cu had coated the surface of the wick. However, the Cu
coating on the surface of the wick is only11.23%., which was not so significant.
360
Material Research and Applications
(a)
(b)
Figure 5. Wick condition (a) before and (b) after experiment
Conclusion
It can be concluded that the use of CuO-water nano fluid and biomaterials wick can improve the
performance of loop heat pipe as compared to using a water-based fluid and sintered powder wick.
Evaporator temperature at 10 watts was 43 oC, it was 17.3% lower than using water fluid. The values
of small porosity will increase the capillarity that will increase the condensate flow rate into the
evaporator. Wick surface had been coating by CuO-water nano fluid but not so much.
Acknowledgement
The authors would like to thank the DRPM University of Indonesia for funding this research through
Hibah Riset Utama UI 2012.
Literature References
[1]. Yu, Boming., and Ping Cheng : International Journal of Heat and Mass Transfer vol 45 (2002), p.
2983-2993
[2]. Kaya, Tarik., and John Goldak : International Journal of Heat and Mass Transfer Vol 49 (2006), p.
3211-3220
[3]. Reay, David & Peter Kew., Heat Pipe, Theory, Design and Applications, 5th Edition, USA, 2006.
[4]. Leonard L, Vasiliev : Applied Thermal Engineering 25 (2005), p.1-19
[5]. Harris, James R., Modeling, Designing, Fabricating and Testing of Channel Panel Flat Plate
Heat Pipe. Utah State University, (2008), p.1-6
[6]. Ochterbeck, Jay M., Heat Pipe. Departement of Mechanical Engineering Clemson University,
pp.1182-1229.
[7]. Nandy Putra, Yanuar, Ferdiansyah N. Iskandar : Experimental Thermal and Fluid Science 35
(2011), p. 1274–1281
[8]. Ying-CheWeng, Hung-Pin Cho, Chih-Chung Chang, Sih-Li Chen : Applied Energy 88 (2011), p.
1825–1833
[9]. Jung-Chang Wang : International Journal of Thermal Sciences 50 (2011), p. 97-105
[10]. Leonid Vasilieva, David Lossouarn, Cyril Romestant, Alain Alexandre, Yves Bertin,
YauheniPiatsiushyk, Vladimir Romanenkov : International Journal of Heat and Mass Transfer
52 (2009), p. 301–308
[11]. L.L. Vasiliev: Applied Thermal Engineering 28 (2008), p. 266–273
Advanced Materials Research Vols. 875-877
361
[12]. Leonard L. Vasiliev: Applied Thermal Engineering 25 (2005) p. 1–19
[13]. Weibel, Justin A., Suresh V Garimella., and Mark T North: International Journal of Heat and
Mass Transfer vol 53 (2010), p. 4202-4215
[14]. Jinwang Li, Yong Zou, Lin Cheng : Experimental Thermal and Fluid Science 34 (2010), p.
1403–1408.
[15]. R. Kempers, A. J. Robinson, D. Ewing, C. Y. Ching : International Journal of Heat and Mass
Transfer 51 (2008), p. 6039–6046.
[16]. Nandy Putra, Wayan Nata Septiadi, Haolia Rahman, Ridho Irwansyah : Experimental Thermal
and Fluid Science, 40 (2012), p. 10-17
[17]. Frédéric Lefèvre, Jean-Baptiste Conrardy, Martin Raynaud, Jocelyn Bonjour : Applied Thermal
Engineering (2011), p. 1-8.
[18]. Yu-Wei Chang, Chiao-Hung Cheng, Jung-Chang Wang, Sih-Li Chen : Energy Conversion and
Management 49 (2008), pp. 3398–3404
[19]. Kyu Hyung Do, Hyo Jun Ha, Seok Pil Jang : International Journal of Heat and Mass Transfer 53
(2010) p. 5888–5894.
[20]. Nandy Putra, Saputra, M. Iqbal Bimo, Ridho Irwansyah, Wayan Nata S. Experimental Study on
Sintered Powder Wick Loop Heat Pipe. The 4th International Meeting of Advances in
Thermofluids, Melaka, Malaysia, 3rd - 4th October, (2011).
[21]. K.C. Leong and C.Y. Liu : Journal of Porous Materials 4 (1997), p. 303–308
[22]. D.K. Mishra, T.T. Saravanan, G.P. Khanra, S. Girikumar, S.C. Sharma, K. Sreekumar, P.P.
Sinha.: Advanced Powder Technology 21 (2010), p. 658–662.
[23]. K.J. Zan, C.J. Zan, Y.M. Chen, and S.J. Wu : Heat Transfer—Asian Research, 33 (8), 2004
[24]. Yong Tang, Daxiang Deng, Longsheng Lu, Minqiang Pan, Qinghui Wang : Experimental
Thermal and Fluid Science 34 (2010), p. 190–196
[25]. S.W. Kang, W.C. Wei, S.H. Tsai, C.C. Huang : Applied Thermal Engineering 29 (5–6) (2009),
p. 973–979.
[26]. S.W. Kang, W.C. Wei, S.H. Tsai, S.Y. Yang : Applied Thermal Engineering 26 (17–18) (2006),
p. 2377–2382
[27]. Zhen-Hua Liu, Yuan-Yang Li. Ran Bao : International Journal of Thermal Sciences 49 (2010),
p. 1680-1687
[28]. ZhenHua Liu, QunZhi Zhu. : Energy Conversion and Management 52 (2011) p. 292–300.
[29]. Kyu Hyung Do, Hyo Jun Ha, Seok Pil Jang : International Journal of Heat and Mass Transfer 53
(2010), p. 5888–5894.
[30]. Rosari Saleh, Nandy Putra, Suhendro Purbo Prakoso, Wayan Nata Septiadi, Experimental
investigation of thermal conductivity and heat pipe thermal performance of ZnO nanofluids,
International Journal of Thermal Sciences, (2012) In Press.
[31]. Nandy Putra, Rosari Saleh, Wayan Nata Septiadi, A. Okta D, Zein Hamid, Thermal
performance of nanofluids in biomaterial wick loop heat pipes, submitted to International
Journal of Thermal Sciences
Material Research and Applications
10.4028/www.scientific.net/AMR.875-877
The Effect of CuO-Water Nanofluid and Biomaterial Wick on Loop Heat Pipe Performance
10.4028/www.scientific.net/AMR.875-877.356