AFFECT OF 10% WT GALENA POWDER ON THE ABSORBITIVITY OF BLACK PAINT

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1 International Journal of Advanced Research in Engineering and Technology (IJARET) Volume 7, Issue 2, March-April 2016, pp , Article ID: IJARET_07_02_001 Available online at Journal Impact Factor (2016): (Calculated by GISI) ISSN Print: and ISSN Online: IAEME Publication AFFECT OF 10% WT GALENA POWDER ON THE ABSORBITIVITY OF BLACK PAINT Iessa Sabbe Moosa College of Engineering, University of Buraimi, Sultanate of Oman, B.O. Box 890, P.C. 512, Al- Buraimi ABSTRACT Addition of Galena Powder to black paint with a range of particle size has been studied, as a developed selective solar absorber for domestic use for water heating system. The powder used was prepared from an ingot of Galena. Selective surfaces; pure aluminum, black paint, and mixture of black paint with galena powder having particle size range of about 250μm and less greater than 125μm at 10% wt were experimented. Temperature difference ( T) as a function of exposure time has been studied pertaining to the mixture of black paint with Galena powder. Furthermore, microstructure of the used bulk ingot of Galena was investigated by using SEM. An increase of about 5 0 C of water temperature was gained by using the Galena powder compared with black paint. The results of this attempt of research showed that the maximum value of water temperature was around 95 0 C in Al- Buraimi City, Sultanate of Oman. Keywords: Galena ingot, Al- Buraimi City - Sultanate of Oman, high absorbitivity, temperature difference. Cite this Article: Iessa Sabbe Moosa, Affect of 10% Wt Galena Powder on The Absorbitivity of Black Paint. International Journal of Advanced Research in Engineering and Technology, 7(2), 2016, pp HIGHLIGHTS Galena powder has been used in attempt to develop the aborbitivity of black paint for heating system by using solar energy. A range of particle size of Galena powder was mixed with the black paint to increase the aborbitivity of the paint. A maximum water temperature of about 95 0 C was reached with 10 wt% of Galena powder. 1 editor@iaeme.com

2 Iessa Sabbe Moosa 1. INTRODUCTION The Sun is a sphere of very condensed hot gaseous matter with a diameter of about m, mostly hydrogen isotopes combining to form helium atoms with a transformation of a certain mass, which is emitted as solar energy. This process takes place by nuclear fusion in the core of the Sun. The solar power that strikes the Earth is around kw. This value, theoretical and practical information about history of solar energy, thermal collectors, and applications of solar energy has been very well clarified by Kalogirou, 2004 [1]. Brilliant details about using of materials for heating system by solar energy have been almost fully reported by Lenel et al., Kennedy [2, 3]. In 1993, Chatterjee and Pal have declared that thin film of Galena can be used as low cost selective absorber [4]. Large scale applications of hot water system in Europe have been reviewed by Fisch et al. [5]. Materials with high absorbitivity and low emission in the solar spectrum with good stability and accessibility at using the temperatures are required for manufacturing of heating system by solar energy especially for domestic use. Many attempts in the field of finding new selective materials and using solar energy for domestic applications have been reported [6, 7, 8, 9, and 10]. Numerous countries with abundance of Sunshine started utilization of solar energy for water heating system for domestic applications [11, 12, and 13]. Additions of some metal powders to selective materials have been published to increase the thermal conductivity of these materials [14, 15, and 16]. The Sultanate of Oman is classified among countries that receive the highest solar energy in the world as that very well reported by Kazem [17], hence any work of research either theoretical or practical is very essential in the field of solar energy applications. The current work is carried out in Al- Buraimi city at the north-west, Sultanate of Oman, where the solar intensity is very high. This city receives the highest Sunshine hours/day compared with the other cites of the Sultanate of Oman as reported by Al-Badi et al [18]. The goal of this research is to study the affect of Galena powder with particle size within the range greater than 125μ to 250μ on the absorbitivity of black paint as a selective surface for solar energy applications. 2. EXPERIMENTAL METHOD The experimental procedure was started by preparing the following stuff and equipments: Black paint type Berger paints, Allinone, High Gloss Enamel, product of Oman Thinner Liquid type Supreme, CCIA PV , product of Italy Homemade experiment wooden box with double glassing front side, about 1m of length, 15cm of depth, and 20cm of height. The air gap between glasses is of about 1cm Aluminum containers size of 15cm 10cm 4cm with top pipe of about 1.5 cm diameter and length of about 5cm for temperature measurements Digital thermometers Digital balance Galena ingot Stainless steel mortar with its hammer handle Stainless steel micro sieves of about 125μm and 250μm 2 editor@iaeme.com

3 Affect of 10% Wt Galena Powder on The Absorbitivity of Black Paint Bulks of Galena with a diameter of about 2.5 cm were brought from public market in Ajman, UAE. Figure1 shows some parts of Galena ingots as received. Powder of Galena was prepared by following these steps: The lumps of Galena were mechanically crushed to a size of about 2mm and less. The crushed small pieces were manually pulverized by using a stainless steel mortar for about one hour. The obtained powder was sieved by the stainless steel micro-sieves of 125μm, and then by 250μm prior to mixing process with the black paint. After using the sieve of 250μm, the collected powder particle size is within the range from greater than 125μm to 250μm. Figure 1 Reveals some lumps of as received Galena ingot A fracture surface specimen from the received Galena bulks and some produced powder were prepared for SEM tests. Mixing process of the black paint with 10wt% percentage of prepared Galena powder was done. About 40g of black paint was weighed by the digital balance and about 5g of thinner liquid was added and mechanically mixed with the produced powder to be ready for painting process. Three aluminum containers were very well cleaned; one of them was kept as it is, the second was painted by plain black paint, and the third was painted by the mixture of the black paint with the sieved Galena powder by 250μm sieve. The prepared containers were filled with water and then fixed in the homemade wooden box prior to water heating by solar energy. The heating process was employed by setting up the experiments proceeding to start at 9:00 am. The initial temperature T 0 was measured by using the digital thermometer, and then the wooden box was exposed to solar radiation for 7 hours. The temperatures of the water in all containers as a function of exposure time were measured whilst the box was almost perpendicular to the direction of the solar beam. 3. RESULTS AND DISCUSSION Solar energy profile of Al-Buraimi city is shown in figure 2, which shows the monthly average of direct radiation, diffused radiation and global radiation. The maximum value of solar radiation in this city is in June, which is about 9.8 kwh/m 2 /day. 3 editor@iaeme.com

4 Iessa Sabbe Moosa Figure 2 Irradiation of Al-Buraimi, Sultanate of Oman of 2012 [16] The misconstrue study of Galena ingot and powder by the SEM exhibited very brittle fracture surface as shown in figure 3. This brittleness is very important in the subsequent milling process to produce a powder from this ingot. In addition, the EDAX unit attached with the SEM revealed that Galena ingot was found almost compound of PbS [16] Figure 3 a-secondary electron image of fracture surface of galena ingot, 500x, b- Galena powder with magnification of 100x The first attempt of heating process was carried out on the date of by using three containers: pure aluminum, black painted aluminum, and the one painted with mixture of black paint and Galena powder to see the difference between these cases on the water temperatures. The result of this experiment is shown in figure 4, from which it can be concluded that the maximum temperature in the case of the pure aluminum is about 73 0 C, and about 84 0 C in the black painted case, whilst in the case of the mixture painted is around 89 0 C. 4 editor@iaeme.com

5 Affect of 10% Wt Galena Powder on The Absorbitivity of Black Paint Figure 4 Water temperatures against exposure time for three cases, Date: , weather: partially cloudy, weather temp.: 35 0 C The result is very important so as these values of water temperatures can be achieved by using very simple facility even when the weather is partially cloudy. After the first attempt of water heating by solar energy, another try was employed on The feedback of this attempt is exposed in Figure 5. Figure 5 Water temperatures against exposure time for different cases, Date: , weather: little partially cloudy, weather temp.: 34 0 C The result of the third experiment is given in figure 6 from which it can be noticed that the maximum water temperature in the case of the black paint plus 10 wt% of Galena powder with the chosen particle size is higher than that of plain black paint by around 5 0 C, while this value is about C when the particle size within the range of 60μm and less [16]. At the first 5 editor@iaeme.com

6 Iessa Sabbe Moosa Figure 6 Water Temperatures Against exposure Time of three Cases, Date: , weather: sunny, weather temp. : 33 0 C hour of exposing time, the increase in temperature is almost the same, and then starts to increase gradually to the maximum value. This behavior probably is due to the change of the aborbitivity of the mixture of black paint with the Galena powder with temperature increase. A value of maximum temperature of about 95 0 C can be achieved by black paint mixture. The maximum values of temperatures obtained in this trial of research are more than enough for domestic use; consequently black painted aluminum solar heating system is very adequate in Al-Buraimi, and probably in many cities in the Sultanate of Oman. The relation of temperature difference T as a function of exposure time is given in figure 7, from which it can be concluded that the relation is almost exponential form. T=T-T 0, where T is the water temperature after a certain exposure time, and T 0 is the initial water temperature. Figure 7 Shows the relation between T and Exposure Time. 4. CONCLUSION The most important conclusion in this article is that even with a pure aluminum selective surface, a temperature of about 75 0 C as an average can be obtained, which is more than enough for domestic use. The results also showed that the water temperature can be increased by addition of Galena powder to black painted selective 6 editor@iaeme.com

7 Affect of 10% Wt Galena Powder on The Absorbitivity of Black Paint surface. A maximum temperature of about 95 0 C can be achieved by the mixture of the black paint with Galena powder within the range of particle of about greater than 125μm to 250μm at 10% wt. Temperature difference as a function of exposure time is almost exponential relation. However, most of the places in the Sultanate of Oman should use solar heating system for domestic use because of the abundance of solar energy even during the winter season. 5. ACKNOWLEDGEMENTS The author would like to thank Dr. Ahmed Al Rawas of the Sultan Qaboos University, Sultanate of Oman, Physics Department for his great help to use the SEM for microstructure and chemical analysis. Also, the author greatly appreciates Mr. Kalyan Baddipudi of the UoB for proof reading. Many thanks to my students Amal Al Ghailini and Abdol Aziz Al- Saadi for their appreciated help in this work. REFERENCES [1] Kalogirou S. A., Solar thermal collectors and applications, Progress in Energy and Combustion Science 30 (2004), pp [2] LENEL U. R. and P. MLID1 R., A Review of Materials for Solar Heating Systems for Domestic Hot Water, Solar Energy Vol. 32, No. I (1984), pp [3] C.E. Kennedy, Review of Mid- to High-Temperature Solar Selective Absorber Materials, National Renewable Energy Laboratory, 2002, NREL/TP [4] Chatterjee S., Pal U., Low cost solar selective absorbers from Indian Galena, Optical Engineering, Vol. 32, No. 11, November 1993, pp [5] FISCH M N., GUIGAS M., and DALENBÄ CK J. O., A Review of Large- Scale Solar Heating Systems In Europe, Solar Energy Vol. 63, No. 6 (1998), pp [6] SÜzer S., Kadirgan1 F., SÖhmen H. M., Wetherilt A. J., TÜre I.0.E, Spectroscopic Characterization of Al 2 O 3 -Ni selective absorbers for solar collectors, Solar Energy Materials and Solar Cells 52 (1998), pp [7] Wazwaz A., Salmi J., Hallak H., Bes R, Solar thermal performance of a nickel pigmented aluminum oxide selective absorber, Renewable Energy 27 (2002), pp [8] Bostrom T., Wackelgard E., Westin G, Solution-chemical derived nickel alumina coatings for thermal solar absorbers, Solar Energy 74 (2008), pp [9] Shashilaka A. R., Sharma A. K., Bhandari D. R., Solar selective black nickel cobalt coatings on aluminum alloys, Solar Energy Materials & Solar Cells 91 (2007), pp [10] Tharamani C. N., Mayanna S. M, Low-cost black Cu Ni alloy coating for solar selective applications, Solar Energy Materials & Solar Cells 91 (2007), pp [11] Kaldellis J. K., El-Samani K.., Koronakis P., Feasibility analysis of domestic solar water heating systems in Greece, Renewable Energy 30 (2005), pp [12] Maxoulis C. N., Charalampous H. P., Kalogirou S. A, Cyprus solar water heating cluster: A missed opportunity, Energy Policy 35 (2007), pp editor@iaeme.com

8 Iessa Sabbe Moosa [13] Kalogirou S. A., Thermal performance, economic and environmental life cycle analysis of thermosiphon solar water heaters, Solar Energy 83 (2009), pp [14] AlShamaileh E., Testing of a new solar coating for solar water heating applications, Solar Energy 84 (2010), pp [15] Ch aichan M. T and Kazem H. A., International Journal of Renewable Energy Research, Using Aluminum Powder with PCM (Paraffin Wax) to Enhance Single Slope Solar Water Distiller Productivity in Baghdad Iraq Winter Weathers, Vol.5, No.1 (2015), pp [16] Moosa I. S, Effect of Galena powder of 63μm Micrometer Particle Size and Less on The Absorbitivity of Black Paint Mixture, International Journal of Advanced Research in Engineering and Technology (IJARET), Vol. 6, Issue 4 April 2015, pp [17] Kazem H. A., Renewable energy in Oman: Status and future prospects, Renewable and Sustainable energy Reviews, 15 (2011), pp [18] Al-Badi A. H, Malik A., Gastli A., Sustainable energy usage in Oman Opportunities and barriers, Renewable and Sustainable Energy Reviews 15 (2011), pp editor@iaeme.com