THERMAL PERFORMANCE OF CeO 2 -WATER NANOFLUID IN FLAT PLATE SOLAR COLLECTOR

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 9, September 2018, pp , Article ID: IJMET_09_09_060 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed THERMAL PERFORMANCE OF CeO 2 -WATER NANOFLUID IN FLAT PLATE SOLAR COLLECTOR Dharmendra Sharma, Arun Kumar Tiwari Department of Mechanical Engineering, Institute of Engineering and Technology, Lucknow, India ABSTRACT Nanofluid is the new research potential to improve the thermal performance of flat plate solar collector. In this research work, collector efficiency is analyzed with the use of cerium oxide nanoparticle in the base fluid like DM water. Maximum enhancement in thermal conductivity was observed up to 41.7% respectively at 1.5% volume fraction of nanofluid and 80ºC temperature in comparison with DM water (36.4%) used as base fluid at the same temperature and particle volume concentration. Viscosity decreases with increasing the temperature but increases with particle volume concentration of nanofluid at a particular temperature. Experimental results exhibit that the maximum collector efficiency was obtained up to 57.1% at optimum particle volume concentration of 1.0% and mass flow rate of 0.03 Kg/s. The results show that the CeO 2 -water nanofluid as working fluid improves the collector efficiency as compared to water as working fluid. Collector efficiency increases with decreasing the temperature reduced parameter. Maximum efficiency of flat plate collector was observed up to 65.3% at optimum volume fraction (1.0%) of nanofluid and at temperature reduced parameter of At 1.0% optimum particle volume concentration of nanofluid and 700 W/m 2 intensity of solar radiation, maximum collector efficiency was obtained up to 58.1%. Finally, it is concluded that CeO 2 - water nanofluid has excellent thermal properties which improved the performance of flat plate collector. Key words: CeO 2 -Water Nanofluid, Collector Efficiency, Flat Plate Collector, Thermal Conductivity. Cite this Article: Dharmendra Sharma, Arun Kumar Tiwari, Thermal Performance of CeO2-Water Nanofluid in Flat Plate Solar Collector, International Journal of Mechanical Engineering and Technology 9(8), 2018, pp editor@iaeme.com

2 Dharmendra Sharma, Arun Kumar Tiwari 1. INTRODUCTION Solar energy is one of the best sources of renewable energy in the universe. Solar collectors are the kind of green energy devices which are most preferred to utilize this free energy source in domestic and industrial applications. These collectors are very efficient to absorb the solar radiation by the absorber plate and convert it into the heat and then transfer this heat into conventional fluids like water. Flat plate collectors are most primitive and most common type of collectors but these collectors are suffered from relatively low efficiency with the use of conventional fluids. To overcome this critical problem, a new type of fluid is invented by Choi [1] (1995) which is called Nanofluid. Nowadays, most of the scientists and engineers are focusing on new nanotechnology and most efficient devices to harness the solar energy. The mixture of nanoparticles (1-100 nm) and base fluids are known as nanofluids which have superior thermal properties to enhance the performance of the collectors. Nanofluids have a lot of potential in solar thermal applications to improve the collector performance. Scientists are interested to develop the new methods to harness the maximum solar energy. Nanoparticles are the innovative materials with base fluids to enhance the heat absorbing transporting ability. Choi et al. [1] was the first researcher who invented the term nanofluids as the heat transfer fluids and studied the thermal conductivity enhancement of the fluids with nanoparticles and concluded that the effective thermal conductivity can be enhanced by using innovative type of nanofluids. Tiwari et al. [2] elucidated that the enhancement in energetic and exergetic efficiency was found maximum using the MWCNTswater nanofluid in comparison with different type of nanofluids. Yousefi et al. [3] had investigated the collector efficiency with or without the added surface active agent with Al 2 O 3 -water nanofluid experimentally and illustrated for 0.2wt% of the nanofluid, efficiency increased up to 28.3%. Tiwari et al. [4] reviewed the usage of nanoparticles in collectors. He represented about the progressive evaluation on the analysis of applications of nanoparticles with base fluids for enhancing the instant collector efficiency. Javadi et al. [5] reported that the nanofluids have inherent characteristics and concluded that the efficiency can improve at a very low volume concentration of nanoparticles with base fluids in collectors remarkably. Sharafeldin et al. [6] has focused on the efficiency of flat plate solar collector and findings showed the maximum instantaneous efficiency was 71.87% when the [(T i -T a )/G T ] equals to zero for kg/s-m 2 mass flux rate of WO 3 -water nanofluid and at % particle concentration (φ). Tiwari et al. [7] focused on the role of nanofluids in thermophysical properties based on experimental observations. Authors suggested that more potential research is still awaited to get the long term stability for incredible performance enhancement. Said et al. [8] found that thermal conductivity enhancement and efficiency was highest for 13 nm Al 2 O 3 nanoparticle, compared to that of 20 nm Al 2 O 3 nanoparticle. Tiwari et al. [9] has investigated the collector efficiency at different mass flow rates of nanofluids. Experimental results exhibited that at 1.5% optimum particle volume concentration of Al 2 O 3 -water nanofluid, the collector efficiency was determined about 31.64%. Kilic et al. [10] had studied the collector performance using TiO 2 -water nanofluid. He was added Triton X-100 surfactant in solution to the maintained stability of the nanofluid and for eliminate the problem of agglomeration. He obtained the highest instantaneous efficiency up to 48.67% for TiO 2 /water nanofluid. Tiwari et al. [11] reviewed about the rheological behaviour in nanofluids and reported that the nanofluids which exhibit Newtonian behaviour for spherical nanoparticles have a very low value of shear rate. Tiwari et al. [12] reported the thermal performance of solar collectors with the use of hybrid nanofluid and concluded that the MgO hybrid nanofluids was more efficient than CuO hybrid nanofluids. Tiwari et al. [13] experimentally augmented the thermal performance of FPSC using MgO-water nanofluid and found that thermal efficiency enhanced up to 9.34% and exergy efficiency was observed 32.23% at particle volume concentration of 0.75% and mass flow rate of 1.5 lpm. Nasrin et al. [14] editor@iaeme.com

3 Thermal Performance of CeO2-Water Nanofluid in Flat Plate Solar Collector illustrated that Ag-water nanofluid has superior thermal properties which obtained maximum heat transfer rate in comparison with Al 2 O 3 -water nanofluid, CuO-water nanofluid and Cuwater nanofluid. Yousefi et al. [15] investigated experimentally that the efficiency decreased without the use of surfactant and increased with surfactant for 0.2 wt% MWCNT-water nanofluid and efficiency was increased without surfactant at 0.4% MWCNT-water nanofluid. 2. EXPERIMENTATION Preparation of nanofluid, data analysis, technical specifications of flat plate collector, experimental setup and procedure has been taken by Verma et al. [2] Measurement of Thermal Conductivity and Viscosity Thermal conductivity and viscosity are essential thermophysical properties of the nanofluid and measured experimentally for accurate and reliable measurement. Samples are prepared for characterization of CeO 2 /water nanofluid at varying temperature (55ºC, 60ºC, 65ºC, 70ºC, 75ºC, and 80ºC) and volume fraction (0.25%, 0.50%, 0.75%, 1.00%, 1.25% and 1.50%) for measuring thermal conductivity and viscosity experimentally. Thermal conductivity is a very important parameter for heat transfer enhancement. The values of thermal conductivity of used nanofluid are measured using a hot wire transient technique (KD-2 Pro thermal properties analyzer, Decagon company, Inc., USA). Experimental results are indicated that the thermal conductivity increases linearly at varying volume concentration and temperatures as shown in Fig. 1. Thermal conductivity mainly depends on the temperatures because of the energized nanoparticles with the molecules of the base fluid. It can be concluded that the nanofluids have a lot of potentials as compare to base fluids to enhance the heat transportability. Variation in performance parameters to enhance thermal conductivity is followed as: type of base fluid, particle volume fraction, ph value, temperature, the shape of a nanoparticle, type of material, surfactant and size of nanoparticles. Results exhibit that the maximum ratio of thermal conductivity of nanofluid and DM water was observed up to 41.72% at an 80ºC temperature and 1.50% volume concentration. Figure 1 Graph between thermal conductivity ratio and temperature editor@iaeme.com

4 Dharmendra Sharma, Arun Kumar Tiwari Viscosity is an inherent thermophysical property of fluids which arises due to frictional resistance between the adjacent layer of nanoparticles and fluids. It has the ability to transport heat of energy systems to improve the performance of the nanofluids. The viscosity of the used nanofluid was measured using the LVDV-II + Pro Brookfield Digital Viscometer Brookfield Engineering Laboratories, Inc.). Viscosity of the used nanofluid was measured at varying temperatures (55ºC, 60ºC, 65ºC, 70ºC, 75ºC and 80ºC) and volume concentration (0.25%, 0.50%, 0.75%, 1.00%, 1.25% and 1.50%) respectively. From the observation of experimental data, it is concluded that the viscosity increases linearly with particle volume fraction due to cohesive forces among like and unlike molecules increases at higher particle volume concentration as shown in Fig. 2 for CeO 2 /water based nanofluid respectively. Further viscosity decreases with an increase in temperature because of fall in cohesive forces predominantly and across the adjacent layers, the viscosity increases marginally due to enhanced momentum transfer. Viscosity is more expressive in liquids due to cohesive forces than due to momentum transfer across the adjacent layers of the fluids. Figure 2 Viscosity versus temperature graph 3. RESULTS AND DISCUSSIONS Experimental observation of flat plate collector was administrated to find out variation in collector efficiency at varying mass flow rates (0.01 Kg/s, 0.02 Kg/s, 0.03 Kg/s, 0.04 Kg/s and 0.05 Kg/s) and at different particle volume concentration (0.25%, 0.50%, 0.75%, 1.0%, 1.25%, 1.50% and 2.0%). Fig. 3 shows the relation between collector efficiency and particle concentration at varying mass flow rates. In this graph, collector efficiency increases for each mass flow rate of nanofluid with volume concentration up to a certain point of volume concentration (1%) and decreases the collector efficiency with particle concentration after this valuable point of concentration. Experimental results exhibit that the maximum efficiency of flat plate collector was observed up to 57.1% at optimum value of mass flow rate (0.03 Kg/s) and particle concentration (1%) respectively. Fig. 4 illustrates the collector efficiency and reduced temperature difference parameter at the volume concentration of 0.25% to 2%. From the observed data, the efficiency of flat plate collector is inversely proportional to temperature reduced parameter at different particle editor@iaeme.com

5 Thermal Performance of CeO2-Water Nanofluid in Flat Plate Solar Collector concentrations. It means collector efficiency increases with decreasing the temperature reduced parameter. Experimental results show that the maximum efficiency was observed up to 65.3% at optimum particle volume concentration of 1% and optimum temperature reduced parameter of and minimum collector efficiency was measured up to 54.6% at temperature reduced parameter of 0.02 and particle volume fraction of 2% respectively. So, the temperature reduced parameter should be minimum for enhancement in efficiency of flat plate collector. Figure 3 Collector efficiency versus mass flow rate Figure 4 Collector efficiency versus reduced temperature difference parameter The Intensity of radiation is the heart of any kind of collector because collector efficiency depends on solar intensity at varying particle concentrations from 0.25% to 2%. Results illustrate that the maximum collector efficiency was obtained up to 58.1% at an optimum particle concentration of 1% and solar intensity of 700 and minimum collector efficiency was observed up to 43.1% at the intensity of 300 and concentration of 2% respectively. From experimental data, collector efficiency decreases beyond optimal values as shown in Fig editor@iaeme.com

6 Dharmendra Sharma, Arun Kumar Tiwari Figure 5 Graph between collector efficiency and radiation intensity 4. CONCLUSIONS AND FUTURE RECOMMENDATIONS 4.1. Conclusions The present research work focuses on improvement in thermal performance of flat plate collector using CeO 2 -water nanofluid at varying mass flow rates (0.01 Kg/s, 0.02 Kg/s, 0.03 Kg/s, 0.04 Kg/s and 0.05 Kg/s) and different particle volume concentration (0.25%, 0.50%, 0.75%, 1.0%, 1.25%, 1.50% and 2.0%) respectively in comparison with DM water as base fluid. At 1.0% optimum particle volume concentration and 0.03 Kg/s mass flow rate, maximum collector efficiency has been calculated up to 57.1%. At temperature reduced parameter and optimum volume fraction, efficiency is observed up to 65.3% and for 700 W/m 2 intensity of radiation, maximum instantaneous efficiency is found up to 58.1% at the same optimum point of volume concentration. Thermal conductivity and viscosity of nanofluid is also investigated experimentally at different particle volume concentration (0.25%, 0.50%, 0.75%, 1.00% 1.25% and 1.50%) and at different temperatures (55ºC, 60ºC, 65ºC, 70ºC, 75ºC and 80ºC) and observed that the Maximum enhancement in thermal conductivity is obtained up to 41.7% at 80ºC temperature and 1.5% volume concentration. Viscosity has been found linear function at different concentration and temperatures. Viscosity is inversely proportional to temperature at different volume concentration Future Recommendations Long-term stability of nanofluids suspension is still needed more attention. Hybrid nanofluids will be the new challenging area for researchers and scientists. Rheological behaviour of nanofluids, Brownian motion of nanoparticles and the dynamic properties of nanofluids are recommendations for future research work. Practical applications of usage of nanofluid are still in critical phase due to the formation of sedimentation, agglomeration and clogging in a flow path editor@iaeme.com

7 REFERENCES Thermal Performance of CeO2-Water Nanofluid in Flat Plate Solar Collector [1] Choi, S.U.S., Eastman, J.A., Enhancing thermal conductivity of fluids with nanoparticles. ASME International Mechanical Engineering Congress & Exposition, San Franscisco, CA., : p [2] Verma, S.K., A.K. Tiwari, and D.S. Chauhan, Experimental evaluation of flat plate solar collector using nanofluids. Energy Conversion and Management, : p [3] Yousefi, T., et al., An experimental investigation on the effect of Al2O3 H2O nanofluid on the efficiency of flat-plate solar collectors. Renewable Energy, (1): p [4] Verma, S.K. and A.K. Tiwari, Application of Nanoparticles in Solar collectors: A Review. Materials Today: Proceedings, (4-5): p [5] Javadi, F.S., R. Saidur, and M. Kamalisarvestani, Investigating performance improvement of solar collectors by using nanofluids. Renewable and Sustainable Energy Reviews, : p [6] Sharafeldin, M.A., G. Gróf, and O. Mahian, Experimental study on the performance of a flat-plate collector using WO 3 /Water nanofluids. Energy, : p [7] Verma, S.K. and A.K. Tiwari, Characterization of Nanofluids as an advanced heat transporting medium for Energy Systems. Materials Today: Proceedings, (2): p [8] Said, Z., R. Saidur, and N.A. Rahim, Energy and exergy analysis of a flat plate solar collector using different sizes of aluminium oxide based nanofluid. Journal of Cleaner Production, : p [9] Tiwari, A.K., Ghosh, Pradyumana, Sarkar, jahar Solar Water Heating Using Nanofluids- A Comprehensive Overview and Environmental Impact Analysis. IJETAE, (3): p [10] Kiliç, F., T. Menlik, and A. Sözen, Effect of titanium dioxide/water nanofluid use on thermal performance of the flat plate solar collector. Solar Energy, : p [11] Sharma, A.K., A.K. Tiwari, and A.R. Dixit, Rheological behaviour of nanofluids: A review. Renewable and Sustainable Energy Reviews, : p [12] Verma, S.K., Tiwari, Arun Kumar, Tiwari, Sandeep, Chauhan, Durg Singh, Performance analysis of hybrid nanofluids in flat plate solar collector as an advanced working fluid. Solar Energy, : p [13] Verma, S.K., A.K. Tiwari, and D.S. Chauhan, Performance augmentation in flat plate solar collector using MgO/water nanofluid. Energy Conversion and Management, : p [14] Nasrin, R., S. Parvin, and M.A. Alim, Heat Transfer by Nanofluids Through a Flat Plate Solar Collector. Procedia Engineering, : p [15] Yousefi, T., et al., An experimental investigation on the effect of MWCNT-H2O nanofluid on the efficiency of flat-plate solar collectors. Experimental Thermal and Fluid Science, : p editor@iaeme.com