Performance Investigation on Solar Still with PCM and Nano

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Performance Investigation on Solar Still with PCM and Nano-Composites: Experimental Investigation 1

Hemin Thakkar, 2Dr. Hitesh Panchal

1

Lecturer, Mechanical Engineering Department, Govt. Polytechnic, Ahmedabad, Gujarat, India.

2

Assistant Professor, Department of Mechanical Engineering, Gujarat Power Engineering & Research Institute, Mehsana, Gujarat, India

Abstract: This Research paper reveals the performance investigation on solar still Integrated with Nano-composites with and without use of paraffin wax as a Phase change material. For the evaluation of performance, three identical 1 square meter area solar stills have used. First solar still integrated with Nanocomposites and PCM, second with only Nano-composites and third is without Nano-composites and PCM. For the preparation of Nano-composites aluminum oxide is used and coated on the surface of the Absorber plate. It has found that, solar still integrated Nano-composites found 92% more productive compared with alone solar still and only Nano-composites integrated solar still is 106 % more productive compared with alone solar still. Keywords: Nano-composites, PCM, Solar still, distillate output, cumulative distillate output.

I. INTRODUCTION

W

ater is essential for the survival of all living things. Three quarters of the earth's surface is covered with water, and through a process called the hydrologic cycle it is distributed to most of the land masses. The hydrologic cycle is simply the evaporation and precipitation of water supplied from the oceans, surface water, and transpiration of plants. The evaporated water condenses into clouds, which are carried away by winds to different locations and eventually released in the form of rain or snow. The hydrologic cycle is continuously repeated and is powered from the solar energy, which causes water evaporation and moving the wind. As the water falls through the atmosphere, it may dissolve gases and accumulate fine particles such as soot and factories emissions. Reaching the ground, the water will pick up organic materials, minerals and clays. Surface water is highly affected by seasonal changes. The water temperature as well as the composition may vary considerably with time over the year. During summer months, bacteria will grow more readily. In cold climate during winter months, the solid contents of surface water are increased due to ice formation. During autumn, decaying of organic matter such as leaves increases the organic matter concentration in the surface water. Many research work has been reported to enhance the yield of still and reviewed here. Adulhai M. Radhwan (2004) studied

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the transient performance of a stepped solar still with built_in latent heat thermal energy storage [1]. Abdallah et al. (2009) studied the performance evaluation of solar distillation using vacuum tube coupled with photovoltaic system [2]. Ahmed Z. Al_Garni (2012) studied the enhancing the solar still using immersion type water heater produc_ tivity and the effect of external cooling fan in winter [3]. Anburaj et al. (2013) studied the performance of an inclined solar still with rectangular grooves and ridges [4, 5]. El_Sebaii et al. (2009) investigated a single basin solar still using sensible heat storage to enhance the overnight productivity of the still [6]. Also, El_Sebaii et al. (2009) reported the single basin solar still consist PCM as Stearic acid [7]. FarshadFarshchiTabrizi et al. (2010) presented two cascade solar stills with and without latent heat thermal energy storage system were constructed for comparison of the still productivity in sunny and cloudy days [8]. Hitesh N. Panchal and Shah (2013) conducted an performance analysis of double basin solar still with evacuated tubes [8-26]. The main aim of this research work is to investigate the effect of Nano-composites and PCM on the distillate output of alone solar still. II. EXPERIMENTAL SET UP Fig. 1 shows the experimental set up of solar stills installed at Gujarat Power Engineering & Research Institute, Mehsana, India. Fig. 2 shows data logger attachment with computer for continuous logging parameters for the experiments. The experimental setup consists of three passive solar stills with condensing glass cover inclination of 23° (Latitude of Mehsana City), fabricated to accommodate 0.040 m water depth maximum. All stills possess glass thicknesses of 0.004 m respectively. First solar still is integrated with Nanocomposites and PCM. Second is integrated with NanoComposites and third is without Nano-Composites and PCM. The bottom surface of each still was painted black for higher absorptivity. Vertical side of the still was at a depth of 0.250 m, whereas the height of the vertical side was kept 0.450 m. The effective basin area of each still is kept 1 m × 1m and it is made of Fiber reinforced plastic (FRP) of 0.050 m insulation thickness.

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control valve. Table 1 shows instruments used in the experiments with accuracy, range and errors. Table 2 shows dimensions of solar still. Table 1 : Measuring Instruments with Accuracy, Range and Errors.

Fig. 1 Experimental Set up of Solar stills.

Sr. No.

Instrument

Accuracy

Range

1

Copper Constantan Thermocouple

±0.1°C

0-100°C

2

Solarimeter

±1W/m2

01400W/m2

2.5%

3

Measuring Jar

±10 ml

0-1000 ml

10%

4

Anemometer

± 1 m/s

0-15 m/s

10%

% error

5%

Table 2: Dimensions of Solar still Parameter

Value

Area of basin in solar still

1 m2

Outer area of solar still

1.05 m × 1.05 m

Inclination of glass cover

23°

Lower end height of solar still

0.30 m

Higher end height of solar still

0.45 m

Insulation thickness

0.05 m

III. RESULT AND DISCUSSION Fig.2 Datalogger integrated with Solar still and laptop

Here, total seven thermocouples are located inside stills. Among, seven thermocouples, six measured water and glass cover temperatures and seventh exposed to atmosphere to measure ambient temperature. The output from the still is collected through a channel fixed at the end of the smaller vertical side of the basin. A water tank (50 kg capacity) is installed in the system as a constant head tank which is used to control the level of water inside the still (maintain the water level in the basin constant along time) by using a solenoid

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In this section, the experimental results are discussed. The experiments were conducted without PCM material on typical day on 10th May 2015 at Mehsana (Latitude: 23°57 N,).The basin water temperature, ambient temperature, inner glass cover temperature and radiation are measured by appropriate instruments and its variation is shown in Fig. 3 and 4. The global solar radiation values arranges from 650 to 1200 W/(m2K) in the time interval 8 AM to 2 PM. The recorded glass cover temperature is higher than the ambient temperature. Fig. 3 shows the solar still integrated without use of PCM and Fig. 4 shows with PCM.

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80 70 60 50 40 30 20 10 0 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00:00 1:00 2:00 3:00 4:00 5:00 6:00

Solar Insolation

900 800 700 600 500 400 300 200 100 0

Water Temperature

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Time (hr) Ta

Solar Insolation

Tw

Tci

Solar Insolation

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Ta

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Water Temperature

Fig. 3 Solar still Temperatures and Insolation (without use of PCM)

Solar Insolation

0.8 0.6 0.4 0.2

4:00

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Distillate water (kg)

Fig. 4 Solar still Temperatures and Insolation (with use of PCM)

Time (h) alone solar still solar still with PCM and Composite Material

solar still without PCM and with Composite Material

Fig. 5 hourly distillate output of solar stills

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2nd International Conference on Multidisciplinary Research & Practice

PCM temperature is found almost close the basin water temperature at 3 PM after reaching the melting point of PCM is 66°C. The day time up to 3 PM, paraffin wax is under the charging mode of heat transfer. The closing of charging process, covering the glass by a cover,the discharging is under the process and stored heat energy is liberated to activate the solar still system during night time. The Fig. 5 shows the yield of distilled water along with cumulative values still the next day morning 7 AM. There is a slight decrease in the yield during day time when compared with still without PCM as the radiation received will be transmitted to the PCM which is kept beneath the basin. So the maximum water temperature is slightly lower than the temperature recorded without PCM. Fig 6 shows the cumulative distillate output of solar stills for its varying conditions. It is clearly shown that the increment in distillate output of 106% and 96% compared with alone solar still for the with PCM and without PCM solar stills.

6 5 4 3 2 1 6:00

5:00

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8:00

0 7:00

Cumulative distillate output (kg)

The hourly distillate output of a solar still is as shown in Figs. 5 and 6 respectively. Hourly distillate output is an output of a solar still gained during every hour. Fig. 5 shows the distillate output of solar still without use of a PCM and Fig. 6 shows with PCM. The yield of solar still is increased up to 550 mL within an hour interval during mid-day as maximum radiation was received and stored by saline water kept in the basin. The maximum distillate output gained in every solar still remains at 01:00 pm due to the summer climate conditions as well as solar insolation. The hourly distillate output of alone solar still, without use of PCM and with PCM is found 2.5, 4.8 and 5.1 kg respectively. The night time distillation of the still would increases the productivity of the solar still and PCM based solar still will enhance the productivity without any additional input. The solar still loaded with PCM alone is tested on 10th May 2015.The operating parameters are measured. The measured

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Time (h) alone solar still solar still without PCM and with composite material solar still with PCM and Composite material

Fig. 6 Cumulative distillate output of solar stills

It is clearly shown that, the solar still is loaded with nanocomposite PCM, the temperature of paraffin wax is slightly higher than the temperature recorded with solar still with PCM. It indicates that heat absorbed by the PCM when nanoparticle is added is quicker since the nano-particle added in the paraffin wax increase the thermal conductivity so the paraffin wax takes more heat energy with lesser time than solar still loaded with PCM. Hence, the yield of solar still with nano-composite PCM is higher than the still with PCM. The cumulative distillate output is not so sensitive between all the three conditions of still without PCM, with PCM and with

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nano-composite PCM (Fig. 6). There is slight increase in the radiation heat transfer between water and glass when solar still is without PCM condition as the temperature of the water is slightly higher than still with PCM and with nanocomposite PCM. The water temperature in the solar still has an influence by PCM. The higher available solar radiation during day time is absorbed by water in without PCM condition. Hence, there is slight difference in the water temperature

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Efficiency (%)

50 40 30 20 10 6:00

5:00

4:00

3:00

2:00

1:00

24:00:00

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0

Time (h) Alone solar still Solar still without PCM and with Composite material solar still with PCM and Composite material Fig. 7 Efficiency of solar stills

The instantaneous efficiency of the solar still is defined as the ratio of energy required for distillate and amount of solar energy falling on the solar still surface. efficiency of the solar still without phase change materials is plotted in the Fig. 7 and it shows the values are varies from the value of 8 to 29% consistently and dropped to the value of 29 to 26% after noon time. The reason for the drop in instantaneous efficiency is drop in the solar radiation in the afternoon onwards. About 6 PM, the stored sensible thermal energy in basin liner and water to drive the solar still operate still further and to extract the distillate output. IV. CONCLUSION The performance of the solar still with nano-composite phase change materials was studied in this report along with and without PCM experimentally. The condensed water collected without PCM, with PCM and nano-composite PCMs are 2.5, 4.8 and 5.1 kg respectively. Initially, solar still without PCM is studied and to enhance the productivity, the passive solar still was integrated with nano-composite phase change material. The solar still becomes more effective when PCM is added with aluminum oxide (Al2O3) as the thermal conductivity of the paraffin wax gets increased when nanoparticle added in that. The energy absorbing rate during day time gets increased. Thermal energy storage rate gets increased in the nano-composite PCM. This was concluded as the yield of still is higher than the still with PCM. The daily yield of solar distillation system has a direct influence by the heat storage capacity and thermal conductivity of the phase change material PCM (Paraffin wax) which is reserved beneath the basin liner. Hence, solar still performance has been studied in terms of yield by using nano-composite phase change material (paraffin wax and Al2O3) and a considerable change was observed change in the yield increased. There is the scope to study further with replacing the aluminum oxide

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(Al2O3) by titanium oxide to know the further enhancement in the yield. Also, to make a comparative study of solar still with aluminum oxide (Al2O3) and titanium oxide based PCM. Furthermore, experimental energy and exergy analysis would be performed and analyzed using the experimental data. ACKNOWLEDGEMENTS Authors are highly acknowledges the Gujarat Council on Science & Technology for his support for the project (GUJCOST/MRP/125). Also, we thank the Management of Gujarat Power Engineering & Research Institute, Mehsana for their support during this course of research work and the manuscript preparation respectively. REFERENCES [1]. Radhwan, A.M., Transient performance of a stepped solar still with built in latent heat thermal energy storage, Desalination, 2004, vol. 171, pp. 61–79. [2]. Abdallah, S., Abu_Khader, M.M., and Badran, O.,Performance evaluation of solar distillation using vacuum tube coupled with photovoltaic system, Appl. SolarEnergy, 2009, vol. 45, no. 3, pp. 176–180. [3]. Al_Garni, A.Z., Enhancing the solar still using immersion type water heater productivity and the effect of external cooling fan in winter, Appl. Solar Energy, 2012,vol. 48, no. 3, pp. 193–200. [4]. Anburaj, P.R., Samuel Hansen, K., and KalidasaMurugavel, Performance of an inclined solar still withrectangular grooves and ridges, Appl. Solar Energy, 2013, vol. 49, no. 1, pp. 22–26. [5]. Atul Sharma, Tyagi, V.V., Chen, C.R., and Buddi, D., Review on thermal energy storage with phase change materials and applications, Renew. Sust. Energy Rev.,2009, vol. 13, pp. 318–345. [6]. El_Sebaii, A., Al_Ghamdi, A.A., et al., Thermal performance of a single basin solar still with PCM as a storage medium, Appl. Energy, 2009, vol. 86, pp. 1187–1195. [7]. Farshad, F.T. and Ashkan, Z.S., Experimental study of an integrated basin solar still with a sandy heat reservoir, Desalination, 2010, no. 253, pp. 195–199.

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2nd International Conference on Multidisciplinary Research & Practice [8]. Hitesh, N. and Panchal Shah, P.K., Performance analysis of double basin solar still with evacuated tubes, Appl. Solar Energy, 2013, vol. 49, no. 3, pp. 174–179. [9]. Panchal, Hitesh. 2010. “Experimental Analysis of Different Absorber Plates on Performance of Double Slope Solar Still.” International Journal of Engineering Science and Technology 2 (11): 6626–6629. [10]. Panchal, Hitesh. 2011. “Experimental Investigation of Varying Parameters Affecting on Double Slope Single Basin Solar Still.” International Journal of Advances in Engineering Sciences 2 (1): 17–21. [11]. Panchal, Hitesh, Manish Doshi, PrakashChavda, and RanvirgiriGoswami. 2010. “Effect of Cow dung Cakes Inside Basin on Heat Transfer Coefficients and Productivity of Single Basin Single Slope Solar Still.” International Journal of Applied Engineering Research, Dindigul 1 (4): 675–690. [12]. Panchal, Hitesh, Manish Doshi, KeyursinhThakor, and Anup Patel. 2011a. “Experimental Investigation on Coupling Evacuated Glass Tube Collector on Single Slope Single Basin Solar Still Productivity.” International Journal of Mechanical Engineering & Technology 1: 1–9. [13]. Panchal, Hitesh, Mitesh I Patel, Bakul Patel, RanvirgiriGoswami, and Manish Doshi. 2011b. “A Comparative Analysis of Single Slope Solar Still Coupled with Flat Plate Collector and Passive Solar Still.” IJRRAS 7 (2): 111–116. [14]. Panchal, Hitesh, and Pravin Shah. 2011a. “Char Performance Analysis of Different Energy Absorbing Plates on Solar Stills.”Iranica Journal of Energy & Environment 2 (4): 297–301. [15]. Panchal, Hitesh and Pravin Shah. 2011b. “Modelling and Verification of Single Slope Solar Still Using ANSYS-CFX.” International Journal of Energy and Environment 2 (6): 985–998. [16]. Panchal, Hitesh, and Pravin Shah. 2012a. “Effect of Varying Glass Cover Thickness on Performance of Solar Still: In a Winter Climate Conditions.” International Journal of Renewable Energy Research 1 (4): 212–223.

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[17]. Panchal, Hitesh, and Pravin Shah. 2012b. “Investigation on Solar Stills Having Floating Plates.” International Journal of Energy and Environment Engineering 3 (1): 1–5. [18]. Panchal, Hitesh, and Pravin Shah. 2013a. “Experimental and ANSYS CFD Simulation Analysis of Hemispherical Solar Still.” IIRE International Journal of Renewable Energy 8 (1): 1–14. [19]. Panchal, Hitesh, and Pravin Shah. 2013b. “Modeling and Verification of Hemispherical Solar Still Using ANSYS CFD.” International Journal of Energy and Environment 4 (3): 427–440. [20]. Panchal, Hitesh and Pravin Shah. 2013c. “Performance Improvement of Solar Stills via Experimental Investigation.” International Journal of Advanced Design and Manufacturing Technology 5 (5): 19–23. [21]. Panchal, Hitesh, and Pravin Shah. 2013d. “Performance Analysis of Double Basin Solar Still with Evacuated Tubes.” Applied Solar Energy 49 (3): 174–179. [22]. Panchal, Hitesh N., and Pravin K Shah. 2014a. “Enhancement of Upper Basin Distillate Output by Attachment of Vacuum Tubes with Double-Basin Solar Still.” doi:10.1080/19443994.2014.913997. [23]. Panchal, Hitesh, and Pravin Shah. 2014b. “Enhancement of Distillate Output of Double Basin Solar Still With Vacuum Tubes.” Frontiers in Energy 8 (1): 101–109. [24]. Panchal, Hitesh, and Pravin Shah. 2014c. “Enhancement of Upper Basin Distillate Output by Attachment of Vacuum Tubes with Double-Basin Solar Still.” Desalination and Water Treatment 55 (3): 587–595. [25]. Panchal, Hitesh, and Pravin Shah. 2014d. “Investigation on Performance Analysis of Novel Design of Vacuum Tube-Assisted Double Basin Solar Still: An Experimental Approach.”International Journal of Ambient Energy. doi:10.1080/01430750.2014.924435. [26]. Panchal, Hitesh N, Nishant S Thakar, and Vishal N Thakkar. 2014. “Performance Analysis of Various Parameters on Glass Cover of Solar Distiller- Experimental Study.” International Journal of Advance Engineering and Research Development 1 (3): 1–12.

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