Thermoelectric Performances of Seawater and Al2O3 Nanofluids using Battery Facility

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1 Thermoelectric Performances of Seawater and AlO3 Nanofluids using Battery Facility Jung-Chang Wang* and Li-Wei Ye Department of Marine Engineering, National Taiwan Ocean University (NTOU), Keelung 04, Taiwan, R.O.C *Corresponding author: Professor; Abstract- The article investigates some electrolytes (Tap Water, Seawater, and Aluminium oxide nanoparticles based fluid de-ionized water as nanofluids) to enhance the micro-generation and heat transfer capabilities utilizing thermoelectric performance experiments of battery facilities. Firstly, the experiment employs the two-step synthesis with emulsion-ultrasonic technology to make the aluminium oxide nanofluid in order to search the best suspended stability for alumina nanofluid as electrolyte according to Zeta potential, ph value, thermal conductivity, and viscosity in the present study. The AlO3 nanofluid was compared with other two electrolytes to discuss the characteristics of the impact of the output currents, voltages, resistances, and temperature distributions under different operating temperatures, distances and areas of electrodes. Finally, the alumina nanofluid between 0% and % emulsifying effect has the best stability, thermal conductivity and stable current output. Keywords-Ultrasonic; Nanofluid; Thermoelectric; Generation; Electrochemistry I. INTRODUCTION A seawater battery for long lived upper seawater systems had been conducted by Hosom et al. [1]. They designed a family of seawater batteries that span the range from a full surface buoy battery to a small battery that might also be a drogue anchor for use on a drifting float. Zhao et al. [] employed the magnesium alloy as the anode based on the seawater as the electrolyte. The feasibility to apply magnesium alloy sheet to highly effective seawater battery was verified. Seawater is one of the novel green energy materials for marine in the seawater. Seawater battery employs the seawater as the electrolyte [3, 4]. Shinohara et al. [5] showed that the seawater battery is useful for application of long-term power consumption even in the deep-sea basin. Stable power supply is essential for various long-term sea floor geophysical observations. For electric power supply, a Sea- Water Battery (SWB) system with monitoring and control was developed and used. From the monitoring data, the SWB can supply up to the long-term average of at least 13 W. The energy density is estimated to be 318 Wh/kg. Hasvold et al. [6] described a power source for the autonomous control system of a sub-sea well (SWACS) in the Ionian Sea. The unit was deployed in January 1996 at a depth of 180 m. The 650 kwh sea-water batteries uses anodes made from commercial magnesium alloys, sea-water as the electrolyte and oxygen dissolved in the sea-water as oxidant. The inert cathodes are made from carbon fibers. Nano-science and technology has become a novel research area, especially in nanofluids. Because the thermal conductivity coefficients of solids, such as copper, aluminium, and AlO3, are generally much higher than those of fluids, a nanofluid that contains nanoparticles of a higher degree of thermal conductivity dispersed in a continuous liquid phase will simultaneously exhibit the superior thermal conductivity of the solid phase and the excellent fluidity characteristics of the liquid phase [7]. Nanoparticles dispersed in a working fluid can also increase the contact surface area and collision frequency between liquid and solid particles through Van Der Waals force, electrostatic force, stochastic force and hydrodynamic force, leading to an improved boiling heat transfer rate and thermal performance. Nanofluids have demonstrated wide applicability in electrical thermal conductance due to their superior thermal conductivity [8]. The progress of nanofluid has not only been motivating new phenomena and theories, but it also has been leading to industrial revolutions. However, rapid advances in nanotechnology mean particles can be further reduced in size to the nano-scale, thus rendering the preparation of nanofluids economically feasible. This paper utilized ultrasonic vibration technology [9, 10] to prepare the nanofluids. The emulsion agent helps the alumina nanoparticles distribute evenly in deionized water to reduce the aggregation phenomenon upon particle collection and avoids particle powder spray. The prepared alumina nanofluids were characterized for thermoelectric and microgeneration properties by the battery facility in the present paper. A. Multi-Battery facilities II. EXPERIMENTAL APPARATUS AND PROCESS The study employs two-step synthesis with emulsion-ultrasonic technology to modulate the AlO3 nanofluid based on Ref. [9, 10]. Measure the thermo-fluid characteristics including nanoparticle size, Zeta potential, ph value, thermal conductivity, viscosity, and absorbance values through testing instruments, in order to search the best suspended stability for alumina nanofluid as electrolyte. Fig. 1 reveals the manufacturing process of alumina nanofluid and testing experiment instrument set diagram. According to previous literatures [3, 4], the best concentration of the emulsion with QF-DTK-190 water-soluble -35-

2 dispersing agent for AlO3 nanofluids is % wt.. Then, another fixed volume electrolytes is compared with the present alumina nanofluid on the impact of the output current and energy at different operating temperatures using battery facility. Fig. exhibits the battery facility in the present paper. The diameters of the anode and cathode are both mm. Their lengths are all mm with copper and aluminum materials, respectively. Each electrolytic cell had a length of mm, a width of mm, and a depth of 30.8 mm, and the electrolyte solution fixed volume of 60 ml was added to the electrolytic cell. The depth of the electrode in the electrolyte is about 4.78 mm which means that it has a surface area of mm under the surface of each electrode. (a) Manufacturing process of Al O 3 nanofluid (b) Testing instrument setup Fig. 1 Experimental Apparatus [3, 4] (a) Single set of four electrodes (b) Four sets of the battery Fig. Experimental diagram of battery facility\ The present experiments are divided into three parts. First, % wt. AlO3 nanoparticles, % wt. emulsion concentration, % wt. QF-DTK-190 agent (dispersant), and deionized water were deployed and mixed uniformly to manufacture alumina nanofluids with the best suspended stability. The Zeta potential with particle size testing set (Malvern Co., Switzerland), ph meter (Metrohm Co., Switzerland), KD (Decagon Co., USA), Sub spectrophotometer (Hitachi Co., Japan), and viscosity analyzer (Brookfield Co., USA) can measure respectively the thermo-fluid characteristics including nanoparticle size, Zeta potential, ph value, thermal conductivity, absorbance values, and viscosity of electrolytes. Then, after the above steps to select the best AlO3 nanofluid as the electrolyte measured its output current and voltage values at the single battery / four different types of electrodes of different heating temperatures with different electrodes connection method under the same conditions of the surface area of the liquid, is used to test the thermoelectric properties of alumina nanofluid as shown in the Fig. (a), and in addition the same specifications with tap water experiments as a basis for comparison. Finally, four sets of the battery / sixteen electrodes will be adopted to enhance the heat transfer rate and micro-generation performance test, and record the output current and voltage values, respectively, at different operating temperatures and the change in the type of connection between the electrodes, to observe the results and discuss the optimal configuration of alumina nanofluid method with reasonable electrode as a basis for future applications. -36-

3 (a) Drawing (b) Entity Fig. 3 Testing set up B. Seawater Battery Facility Battery is also called electro-chemical cells. It is composed of two different metals from chemical changes in the electrolyte, and the process causes the chemical energy into electrical energy by this chemical reaction. Since 1960s, sea water batteries have been investigated in underwater applications for their simple operation, portable, self-contained, high conversion efficiencies, and excellent storage [11, 1]. An apparatus used in the article is shown in Fig. 3. It consists of transparent cuboids of acrylic, in which the dimensions are 130 x 100 x 70 mm 3 and the thickness of PMMA (Polymethylmethacrylate, Acrylic) is 5 mm. There are four partitions allowed electrolyte and electrodes for series connection into five parts. A measuring device records current and voltage with time and serial effects. The seawater battery employs the Aluminum (Al) and Copper (Cu) alloys as the electrode materials, carbon (C) powder as assisting conduct-electricity material in sea water electrolyte. Seawater was prepared and analyzed of typical components by dissolving properly ratios of Sodium Chloride (NaCl), Potassium Chloride (KCl), Magnesium Chloride (MgCl), Calcium Sulphate (CaSO4) and Sodium Sulfate (NaSO4). These cruds appear to be a mixture of metallic hydroxides resulting from cell reactions including Anode and Cathode effects as Eqs. (1) to (3). Metallic hydroxides deposited on the surface of electrodes or inside the electrolyte because they do not dissolve in water. These metallic hydroxides increase the internal resistance of seawater battery. Another polarization effect will affect the discharge efficiency resulting from the hydrogen generated around the electrodes Al Al 3 e E Volt (1) 1 0 Cu Cu e E Volt () H O e OH 1 0 H E Volt (3) 1.5 Power Consumption 1.8 Power Consumption Voltage(v) Voltage(v) Time(m) Time(m) Fig. 4 (a) Time step of 10 mins (b) Time step of 30 mins III. RESULTS AND DISCUSSIONS For seawater battery facility experiment, we have designed a novel method to explore how many times the seawater battery can deplete. Two kinds of experiments formed with load resistance path let the seawater continued to discharge the seawater battery facility. Each one measures the voltage every 10 minutes at the loading resistance of.95 kω; the other is to let the -37-

4 seawater battery naturally discharge by itself and records the voltage every 30 minutes as shown in Fig. 4. No loading resistance to discharge is shown as in Fig. 5. From these figures, slight touch on the seawater battery will disturb the voltage values, and its value will be steady for a while. The reason is that the bubble generation affected the voltage values. The problem is it to pay attention to designing the series-parallel seawater batteries in the future. There are two groups of the same weight of the surface area of electrodes connected to different load discharge test, and the composition of the two electrode materials is the same, and both are bound to the same power capacity. The seawater battery has about 110 x 90 x 60 mm 3 sea water reservoir. The experiment studies the relationship between discharge and contact area of the seawater batteries electrode. 1.8 Self-discharge 1.7 Voltage(V) Time(day) Fig. 5 Natural discharge TABLE 1 CARBON POWDER OF G Time(min) Voltage(V) TABLE CARBON POWDER OF 30.8 G Time(min) Voltage(V) TABLE 3 PURE WATER S.C Voltage (V) Current (ma) TABLE 4 SEAWATER S.C Voltage (V) Current (ma) Tables 1 and showed that using different metals of potential, water-activated current generated can provide energy. They showed the mean voltage of about 0.34 and 0.3 voltages at Carbon powder of g and 30.8 g respectively. Change the electrode and the carbon powder to the contact area, neither change in the case of other conditions, the test size of the difference between the discharge voltages. The loading resistance is 0 ohm in order to form the circuit, which allows the seawater battery to discharge continually, each process 0 minutes later, gauges its voltage. Metal alloy is usually selected as the seawater battery anode resulting from the discharge force of the higher, good of the discharge performance and light weight. But the chemical reaction of metal materials with sea water generates hydrogen, surrounded by the film formed around the electrodes within the cell impedance; this phenomenon is called polarization, affecting the discharge efficiency. Tables 3 and 4 revealed the electromotive force (E.M.F.) and output currents employing pure water and seawater as electrolytes respectively, which is the relationship between discharge and series connection (S.C.). The E.M.F. is getting higher with adding S.C. and the -38-

5 current of sea water is about ten times than that of pure water. This is because that there is much assisting conduct-electricity material inside the seawater. In the present study, the Al O 3 nanofluid with the best suspended stability had the Zeta potential of.33 mv, mean particle size of nm, ph value of 5.516, the thermal conductivity of 0.66 W/(mK), a viscosity of 1.1 cp, and the absorbance of 1.844,.011, and.95, respectively, light wavelengths of 350 nm, 400 nm, and 500 nm through the thermo-fluid test of a variety of instruments. Using the nature with alumina nanofluids in Fig. (a) of single cell / four electrodes electrolysis tank test its electrochemical experiment, and the same specifications as a tap water electrolyze another electrochemical experiments as a comparative sample, and the results are shown in Fig. 6. The output voltages and currents of both electrolytes are roughly rising with increasing temperatures, showing an upward trend, with increasing electrolyte temperatures from Fig. 6. With the improvement of the electrolyte temperature, voltage and current output also showed a rising trend. Furthermore, the output current of alumina nanofluids is much higher than that of the tap water. There is an average of 4.5 times. (a)output voltage (b)output current Fig. 6 Output energy of tap water and AlO3 nanofluids at Single set of the battery AlO3 nanofluids had lower output voltage than the tap water because of the large number of ions (eg. AlO3 nanoparticles) as the electrolyte solution resulting in lower resistance of nanofluids. However, after the two electrochemical electrolytic solutions experimental data and even the nature of deployment of alumina nanofluids can still find some problems. The electrodes placed on the front part of the single cell must first check whether the oxidation to react with the electrolyte, if oxidation, the first portion need to scrape the surface of the electrode and is oxidized redox smoothly; Secondly, because the electrolyte will gradually warm experiments to detect the change in current and voltage at different temperatures, and the time when stretched, it will make the electrolyte in the cell because of evaporation reduce, evaporation of the tap water and then add only part, but it will be because of nanofluids affect evaporation concentration change, because the change in concentration as the electrolyte nanofluids with the passage of time, alumina nanoparticles gradually attached to the electrode, and perhaps this will also affect the redox electrode reaction. The suspended nanofluids enhance the nanoparticles through the emulsion and dispersant way, but at the time of the experiment with the elongated, or can be found in the cell's electrolyte precipitation phenomenon, in addition to changes in evaporation caused a bit of concentration than mentioned. Finally, The Zeta potential of alumina nanofluids with ph of is too small to make each other less repulsion between nanoparticles, not making the suspension enough to make nanofluids has been maintained in a decentralized state and cause precipitation. IV. CONCLUSIONS From the current progress of the present experiment, the performance of AlO3 nanofluids as an electrolyte is indeed very good, but the natures of the various aspects still need to improve. The present study expected that the electro-chemical reaction of alumina nanofluid can effectively explore and improve both the output battery and heat transfer rate in different electrolytes, operating temperatures, and electrodes areas. Then, the best suspended alumina nanofluid as the electrolyte was to measure its output current and voltage values at the single battery types of electrodes of different heating temperatures with different electrodes connection method under the same conditions of the surface area of the liquid, is used to test the thermoelectric properties of AlO3 nanofluid. The seawater battery has the convenience of usage and storage and may offer the electric power of Direct Current (D.C.) for a long time which causing it unexpected deficient and does not cause the marine pollution. The carbon powder can be uniformly covered around the electrodes at the same electrodes and capacity, the issue of power is almost the same. So long as -39-

6 the seawater battery vibrates light flipping, the voltage starts unstable and will draw steady-state value after a little time. In other words, the air bubble will affect the voltage value in the seawater battery. From the point of view of changes in viscosity, viscosity affected by the concentration of nanoparticles is much greater than adding nano-emulsion fluid; and in the case of emulsification, thermal conductivity decreases with increasing temperature, at about 50 time and began to rise. Since the resistor will be affected by the temperature coefficient, the resistance generally decreases with increasing temperature, while the water resistance is increased by the rise in temperature and the resistance. ACKNOWLEDGMENTS The financial support for this study received from the National Science Council, Taiwan, R.O.C. under grant numbers NSC 10-1-E is gratefully acknowledged. And the author would like to thank all colleagues and students who contributed to this study.. REFERENCES [1] Hosom D S, Weller R A, Hinton A A, Rao B M L. Sea water battery for long lived upper seawater systems. Proceedings of Seawaters '91, Seawaters Conference Record (IEEE), 1991, Vol. 3, pp [] Zhao H, Bian P, Ju D. Electrochemical performance of magnesium alloy and its application on the sea water battery. Journal of Environmental Sciences, 009, Vol. 1, pp. S88-S91. [3] Wang J C. Novel green illumination energy for LED with seawater battery materials. INTERNATIONAL JOURNAL OF MATERIALS & PRODUCT TECHNOLOGY, 01, 44(3/4), pp [4] Wang J C. LED with Seawater Battery. Advanced Materials Research, 01, Vols , pp [5] Shinohara M, Araki E, Mochizuki M, Kanazawa T, Suyehiro K. Practical application of a sea-water battery in deep-sea basin and its performance. Journal of Power Sources, 009, 187(1), pp [6] Hasvold O, Henriksen H, Melvaer E, Citi G, Johansen B O, Kjonigsen T, Galetti R. Sea-water battery for subsea control systems. Journal of Power Sources, 1997, 65(1-), pp [7] Wang J C, Chiang W C. Researches on Thermo-Electric Properties of Seawater and AlO3 Nanofluids. Applied Mechanics and Materials, 013, Vol. 394, pp /. [8] Wang J C, Lin C Y, Chen T C. Thermal performance of a vapor chamber-based plate of high-power LEDs filled with AlO3 nanofluid. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 013, 13(4), pp [9] MURTI V S R, PHILIP P K. An analysis of the debris in ultrasonic-assisted electrical discharge machining. Wear, 1987, 117(), pp [10] Lin C Y, Wang J C, Chen T C. Analysis of suspension and heat transfer characteristics of AlO3 nanofluids prepared through ultrasonic vibration. Applied Energy, 011, 88(1), pp [11] Opitz C L. Seawater Power Supply Using a Magnesium-Steel Cell. 4th Intersociety Energy Conversion Engineering Conference, September, 1964, pp [1] Wilson B J. CHARACTERISTICS OF AN IMPROVED INERT-CATHODE/MAGNESIUM-ANODE SEA-WATER BATTERY. NRL 6715, Naval Research Laboratory, Washington, D.C., Accession Number : AD ,