ENHANCEMENT OF UNIFORM TEMPERATURE DISTRIBUTION ON THE CONCENTRATED SOLAR RECEIVER WITH INTEGRATED PHASE CHANGE MATERIAL

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 9, September 2017, pp , Article ID: IJMET_08_09_033 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed ENHANCEMENT OF UNIFORM TEMPERATURE DISTRIBUTION ON THE CONCENTRATED SOLAR RECEIVER WITH INTEGRATED PHASE CHANGE MATERIAL Ramalingam Senthil, Chinmaya Rath, Mukund Gupta Department of Mechanical Engineering, SRM University, Kattankulathur, Chennai. India ABSTRACT The objective of the study is to produce the uniform heat distribution in the parabolic dish concentrated solar receiver. The output of the system is uniform during the continuous presence of sunlight. A discontinuity of energy flow occurs in the solar receiver during the short unavailability of solar radiations and the absence of the sun s radiation affects the performance of the system. The usage of phase change materials (PCM) as thermal energy storage in a solar system produces effective the thermal performance. PCM enhances the system s ability to produce steam even in the absence of solar radiation for a while by increasing the system efficiency. This work is aimed to know the thermal performance of the system with thermal energy storage. The variation of temperatures is noted as 261 C and 60 C on the receiver surface for charging and discharging respectively. The uniform temperature distribution is observed on the PCM integrated receiver in the absence of solar radiation. Key words: Parabolic dish, thermal energy storage, temperature distribution, solar receiver, PCM. Cite this Article: Ramalingam Senthil, Chinmaya Rath, Mukund Gupta,Enhancement of Uniform Temperature Distribution on the Concentrated Solar Receiver with Integrated Phase Change Material, International Journal of Mechanical Engineering and Technology 8(9), 2017, pp INTRODUCTION The use of solar energy in thermal, electrical and chemical applications are gaining the popularity due to the renewable nature. Many researchers are investigating the effective utilization of the solar energy. Cooking requires the continuous and uniform heat supply. During the discontinuity in solar energy, the solar receiver experiences more non-uniform temperature distribution in the receiver. This variation in temperature decreases the uniform thermal output of the solar cooking systems. The effect of PCM in the solar receiver and thermal accumulation have been researched by several researchers recently [1-3]. Various design factors involved in the parabolic dish concentrated solar receiver, the temperature

2 Ramalingam Senthil, Chinmaya Rath, Mukund Gupta distribution and the fluid flow strategy are investigated to improve the thermal output of the parabolic dish collector [4-6]. The use of sensible and latent heat storage materials in the concentrated solar receivers and the heat transfer enhancement methods are discussed [7-12]. The nanofluid based direct absorption solar collectors is investigated by Senthil and Cheralathan [13] using the parabolic dish collector. Kurnia and Susmito [14] enhanced the melting and charging of PCM through the rotating thermal energy storage. The central receiver and parabolic collectors for power and cooling applications are investigated [15, 16]. The effect of fluid input parameters over the thermal output of the solar receiver is investigated to determine the strong influence parameter [17]. Jaji et al. [18] carried out a parametric study to predict the thermal performance of concentrated receiver integrated with thermal storage. A review on concentrated solar receiver was done to summarize the latest receiver development [19]. The selective coating on solar receiver is analysed [20]. The utilization of PCM in the building envelopes are discussed by Senthil and Sundaram [21]. From the literature, the application of PCM in the solar receiver and thermal management of building are researched recently. An attempt is made to make the receiver temperature as uniform distribution using PCM. The improvement in the uniform temperature distribution is reported in this work. 2. EXPERIMENTAL WORK The parabolic dish is a Scheffler type reflector system with multi-faced mirrors. Each mirror is 3 mm thick, 100 mm wide and 180 mm long. The total reflective area of all the mirrors is 16 m 2, hence the aperture area of the reflector is 16 m 2. The concentrator has a two-axis tracking mechanism which is operated manually by chain linked clockwork mechanism for daily east-west tracking. The focal length of the collector in the system is 2.5 m. The collector is made up of hardened steel. The mirrors are placed in the collector along the frame. The type of mirror type is Saint Gobain Metalia G031, the temperature of the glass is C. The reflectivity of the mirror is 0.9. The seasonal tracking is done by a lever in the centre of the concentrator. The seasonal tracking is done by just pushing and pulling of the lever which is an advantage in Scheffler type reflectors. Figure 1 Experimental setup of Parabolic Dish Concentrator The PCM storage is integrated with the absorber. The outer diameter of the receiver is 360 mm. The inner diameter of the cylinder is 220 mm the wall thickness of the receiver is 5 mm. Fins are made up of mild steel and are brazen along the length of the inner cylinder. The thickness of fins is 2 mm. A glass wool of thickness 170 mm thickness is provided for the

3 Enhancement of Uniform Temperature Distribution on the Concentrated Solar Receiver with Integrated Phase Change Material insulation. The total length of the receiver is 300 mm. The thickness of plate which is used to make the receiver is 2.5 mm. The fabrication of the proposed receiver with PCM in the periphery of the receiver has been carried out and the receiver has been tested in the real-time environment. (a) (b) Figure 2 (a) Solar receiver during the charging; (b) The insulated solar receiver after charged. 3. RESULTS AND DISCUSSION The PCM integrated receiver has been tested in the real-time environmental conditions in March The intensity of beam radiation ( W/m 2 ), ambient temperature (32 to 35 C) and wind velocity (0 to 2 m/s) were measured during the test periods. The cooling of receiver is done in without insulation and with insulation. The different quantity of water is tested. The temperatures of water were measured with RTD-100 thermocouples. The surface temperatures of both the cases were compared in the context of heat losses. Wind velocity and ambient temperature were measured by the anemometer. The radiation was measured by the pyranometer. Sodium Nitrate and Potassium Nitrate are used as a PCM in 60:40 ratio. The different test are conducted to find out the heat losses and energy stored by the receiver. (a) (b) Figure 3 Thermal Image of the receiver: (a) During charging; (b) After defocus of the reflector From Figure 3, the temperature distribution is oberved with more non-uniform during the charging of PCM integrated solar receiver. The peak temperature is observed to be C and lower temperature at the periphery is observed to be C from the thermal image (Fluke make). However, during the absence of solar radiation the receiver is observed with more uniform temperature distribution in Figure 3 (b). The peak and low temperature are

4 Ramalingam Senthil, Chinmaya Rath, Mukund Gupta observed to be C and C respectively. The variation of temperatures is noted as 261 C and 60 C on the receiver surface for charging and discharging respectively. Figure 4 Heat store Vs Melting temperature Figure 5 Mass of water Vs Quantity of water The discharging time of receiver with insulation it takes 6 to 7 hr for complete charging process. This is due to low heat loss effect due to glass wool and the low thermal conductivity. The reading with insulation are repeated for five days. It is concluded that with insulation system is more effeicient as compare to without insulation, with insulation receiver not librate the heat to its surrounding due to high thermal conductivity of alluminium. So, it takes less time for complete charging of receiverit takes 1 to 1.5 hr for complete charging to reach 310 ο C. temperature. The different different quantity of water are tested under different

5 Enhancement of Uniform Temperature Distribution on the Concentrated Solar Receiver with Integrated Phase Change Material receiver temperature. With insulation less heat loss takes place. Convection and radiation loss are less when we insulate the receiver perfectly. The heat stored by the receiver with increase in temperature heat stored by the receiver increase. Total heat stored in the receiver is 30 MJ when receiver is heat up to 300 ο C temperature. Figure 5 shows the evaporation of water when we test it for different quantity of water at different receiver temperature. It is seen that the 2.5 kg of water completely evaporated to the steam. Thus, the temperature distribution in the solar receiver is made uniform due to the integration of the PCM. 4. CONCLUSIONS The cylindrical receiver is tested in different operating condition with using PCM NaNO 3 and KNO 3 in 60:40 ratio. The experiment is conducted to test the receiver with insulation and without insulation, and different quantity of water is tested under different receiver temperature. Total heat can be stored in the receiver when receiver is at 300 ο C is kj. 2.5 kg of water completely evaporated when receiver temperature is 280 ο C. It takes 1.5 hr to complete charging reaching 300 ο C temperature when receiver is perfectly insulated. The variation of temperatures is noted as 261 C and 60 C on the receiver surface for charging and discharging respectively. Cooling rate of PCM integrated receiver takes 6 hr to reach the ambient temperature when receiver is perfectly insulated. Thus, the uniform receiver temperature distribution is achieved with integration of PCM in the soalr receiver. REFERENCES [1] Mikelis Dzikevics, Vladimirs Kirsanovs, and Dagnija Blumberga, Design of Experimental Investigation about the Effects of Flow Rate and PCM Placement on Thermal Accumulation, Energy Procedia, 113, 2017, pp [2] M. Khalil Anwar, B.S. Yilbas, and S.Z. Shuja, A thermal battery mimicking a concentrated volumetric solar receiver, Applied Energy, 175, 2016, pp [3] B. S. Yilbasa, and M. Khalil Anwar, Design of a mobile thermal battery and analysis of thermal characteristics, Journal of Renewable and Sustainable Energy 8, , [4] R. Senthil, and M. Cheralathan, Effect of non-uniform temperature distribution on surface absorption receiver in parabolic dish solar concentrator, Thermal Science (2015) doi: /TSCI S. [5] R. Senthil, and M. Cheralathan, Effect of once-through and recirculated fluid flow on thermal performance of parabolic dish solar receiver. Indian Journal of Science and Technology. 9 (33), 2016, doi: /ijst/2016/ v9i33/ [6] A. Z. Hafez, Ahmed Soliman, K.A. El-Metwally, and I.M. Ismail, Design analysis factors and specifications of solar dish technologies for different systems and applications, Renewable and Sustainable Energy Reviews, 67, 2017, pp [7] R. Senthil, M. Cheralathan, Thermal performance of solid and liquid energy storage materials in a parabolic dish solar cooker, International Journal of Chemical Sciences 2016, 14 (4), pp [8] R. Senthil and M. Cheralathan, Natural heat transfer enhancement methods in phase change material based thermal energy storage, International Journal of ChemTech Research, 9 (5), 2016, pp [9] A. Arunasalam, A. Ravi, B. Srivatsa, and R. Senthil. Thermal Performance Analysis on Solar Integrated Collector Storage. UARJ, 1 (2), 2012, pp [10] R. Senthil, and M. Cheralathan, Effect of PCM in a solar receiver on thermal performance of parabolic dish collector, Thermal Science (2016) doi: /TSCI S

6 Ramalingam Senthil, Chinmaya Rath, Mukund Gupta [11] R. Senthil, and M. Cheralathan, Energy and exergy analysis of a parabolic dish concentrated solar receiver with integrated PCM, International Journal of Advance Research in Science and Engineering, 5 (10), 2016, pp [12] R. Senthil, and M. Cheralathan, Effect of container size on thermal performance of sugar alcohol (D-Mannitol) in concentrated solar receiver, International Journal of Chemical Sciences, 14 (4), 2016, pp [13] R. Senthil, and M. Cheralathan, Enhancement of heat absorption rate of direct absorption solar collector using graphite nanofluid, International Journal of ChemTech Research, 9(9), 2016, pp [14] Jundika C. Kurnia and Agus P. Sasmito, Numerical investigation of heat transfer performance of a rotating latent heat thermal energy storage, Applied Energy, 2017, [15] Sandhya Jadhav and V. Venkat Raj, Simulation of solar thermal central receiver power plant and effect of Weather conditions on thermal power generation, International Journal of Mechanical Engineering and Technology, 8 (2), 2017, pp [16] G. Chandra Mohana Reddy, G. Ananda Rao, V.V.S. Harnadh Prasad and M. Vishnu Vardhan, Design of concentrated parabolic dish collector for vapour absorption refrigeration system. International Journal of Civil Engineering and Technology, 8 (7), 2017, pp [17] R. Senthil, S. Prabhu and M. Cheralathan, Effect of Heat Transfer Fluid Input Parameters on Thermal Output of Parabolic Dish Solar Receiver Using Design of Experiment Techniques, International Journal of Mechanical Engineering and Technology 8(8), 2017, pp [18] Jaji Varghese, Samsher and K. Manjunath, A parametric study of a concentrating integral storage solar water heater for domestic uses, Applied Thermal Engineering 111 (2017) [19] R. Senthil, Recent Developments in the Design of High Temperature Solar Receivers, International Journal of Mechanical Engineering and Technology 8(8), 2017, pp [20] P. Sundaram and R. Senthil, Effect of Selective Coatings on Solar Absorber for Parabolic Dish Collector. Indian Journal of Science and Technology. 9 (48), 2016, doi: /ijst/ 2016/v9i48/ [21] R. Senthil and P. Sundaram, Effect of Phase Change Materials for Thermal Management of Buildings, International Journal of Civil Engineering and Technology, 8(9), 2017, pp [22] R. Senthil, S. Prabhu and M. Cheralathan, Effect of Heat Transfer Fluid Input Parameters on Thermal Output of Parabolic Dish Solar Receiver Using Design of Experiment Techniques, International Journal of Mechanical Engineering and Technology 8(8), 2017, pp [23] R. Senthil, Recent Developments in the Design of High Temperature Solar Receivers, International Journal of Mechanical Engineering and Technology 8(8), 2017, pp