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International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163 Volume 1 Issue 8 (September 2014) www.ijirae.com ______________________________________________________________________________________________________ © 2014, IJIRAE- All Rights Reserved
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    International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163   Volume 1 Issue 8 (September 2014 )   www.ijirae.com ______________________________________________________________________________________________________ © 2014, IJIRAE- All Rights Reserved Page -199 Experimental Analysis of Parabolic Solar Dish with Copper Helical coil Receiver    Vinayak Sakhare   V.N.Kapatkar    Assistant Professor Associate professor Sinhgad College of Engg,Pandharpur Sinhgad College of Engg,Pune  Abstract— Solar Parabolic Dish is currently used for the Water heating and cooking applications. Generally Solar  Parabolic Dishes are fixed focus point concentrators, but in order to achieve higher thermal efficiency we tried to make it line focus concentrator by using a unique receiver (copper tube in the form of helical coil) mounted at focal point.This  report presents experimental platform based on the design, development and performance characteristics of direct steam  generation by non-tracking solar paraboloidal dish concentrating system. The performance of the concentrator is experimentally investigated with the water circulated as heat transfer fluid. The system is fabricated with highly reflective  aluminium foil sheet (0.8 reflectance factor). The experimental setup is placed in open, and the tests were carried out. The  collector’s efficiency was noted. The results are encouraging to provide the data for developing steam generation for rural  application. The concentrated heat is absorbed by a copper tube which is made up of coil in a curved shape (22cm diameter  and length with 15 no of turns) and it is fixed on solar trace path in which, it is eliminates tracking the sun in the east west  direction and optimal tracking of the sun in the north-south to obtain maximum solar energy. The experimental results are  taken on summer and cloud free days. The test results were measured 215  o C with solar steam conversion efficiency is 60-70%  measured.  Keywords— Point Concentrator, Focal Point, Coil Receiver I. I NTRODUCTION   Sun is the singular source of renewable energy that sits at the center of the solar system. This energy is released at the rate of 3.83 10 26 W. The intensity of solar radiation per unit time on a unit surface outside the earth’s atmosphere is known as “solar constant”. Its value is 1353 W/m 2 . The solar radiation as received on the earth’s surface is composed of the following: i)   Beam radiation (I  b ) is that solar radiation which is received directly from sun without change of direction. ii)   Diffuse radiation (I d  ) is that solar radiation which is received directly from sun after its direction has been changed by reflection. iii)   Global radiation (I g ) is the sum of beam and diffused radiation M. Mohamed, Auatf.S.Jassim, Yaseen. H. Mahmood   [6] , carried out design and fabrication of solar dish concentration with diameters (1.6) meters for water heating application and solar steam was achieved .The dish equipped with tracking system and measurement of the temperature and solar power. Water temperature increased up to 80 Co, and the system efficiency increased by 30% at mid noon time. Ibrahim Laden Mohammed  [1]  carried out design and development of a  parabolic dish solar water heater for domestic hot water application (up to100oC) is described. The heater is to provide 40 litres of hot water a day for a family of four. Thermal efficiencies of 52% - 56% were obtained, and this range of efficiencies is higher than the designed value of 50%. Meenakshisundaram Arulkumaran and William Christraj  [2] experimentally investigated with the water circulated as heat transfer fluid. The concentrated heat is absorbed by a copper tube which is made up of coil in a curved shape and it is fixed on solar trace path in which, it is eliminates tracking the sun to obtain maximum solar energy. The test results were measured 215 o C with solar steam conversion efficiency is 60-70% measured. Joshua Folaranmi  [5]  carried out design, construction and testing of a parabolic dish collector, where heat from the sun is concentrated on a black absorber located at the focus point of the reflector in which water is heated to a very high temperature to form steam. The whole arrangement is mounted on a hinged frame supported with a slotted lever for tilting the parabolic dish reflector to different angles so that the sun is always directed to the collector at different period of the day. On the average sunny and cloud free days, the test results gave high temperature above 200°C. Adel M. Al-Nasser   [4]  said that Hourly values of useful energy gain are calculated after considering the optical and thermal losses of the collector. The months of April and August offer the largest irradiation and useful solar energy rates compared to other months. The prediction hours starts from 5 a.m. to 8 p.m. to account for variation in sunrise and sunset times of different months. It is observed that thermal losses provide low proportion to the absorbed radiation predicted at 3.5%. Cédric Philibert  [3]  studied present and future use of solar thermal energy. The main technologies belong to either “passive” and “active” solar energy forms. Passive solar energy relates to the design of buildings collecting and transforming solar energy    International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163   Volume 1 Issue 8 (September 2014 )   www.ijirae.com ______________________________________________________________________________________________________ © 2014, IJIRAE- All Rights Reserved Page -200 used for day lighting and natural ventilation. Active solar energy relates to the use of solar collectors for water or space heating  purposes, active solar cooling, heat pumps Lifang Li and Steven Dubowsky  [7]  developed new design approach for solar concentrating parabolic dish based on optimized flexible petals.   The dish mirror is formed from several optimal-shaped thin flat metal petals with highly reflective surfaces. Attached to the rear surface of the mirror petals are several thin layers whose shapes are optimized to have reflective petals form into a parabola when their ends are pulled toward each other by cables or rods. II.   E XPERIMENTAL S ET -U P   The experimental setup consists of a solar parabolic dish system, absorber, and heat transfer fluid as water which is circulated through the system from water tank. A galvanized steel pipe is used to carry the water from tank to the absorber tube and absorber tube is a coiled tube made up of copper. It is located in the focal point on the solar trace of parabolic dish. When the sunlight rays are incident on the reflective surface they are reflected and conveyed to the surface of the tube at the curve to heat the water and to take change phase. The parabolic dish made with highly reflective panels with 0.8 of reflectance factor. The reflector cut into small shapes and fixed parabolic which can be turned conveniently. Fig 1 Parabolic dish concentrator experimental setup. The out let pipe is connected to the other end of the absorber tube and generated steam is delivered to the application. The circulating fluid flow measured by collecting in a vessel with respect to the time. The reflection surface can be deteriorated when exposed to the open atmosphere, and it can be cleaned by rubbing polish and can be washed. It can be maintained with good environment stability and weather ability to be monitored during the test. Many methods have been developed to study the focal image characteristic of heat flux and heat flux on the absorber. III.   E XPERIMENTAL P ROCEDURE   Expected Thermodynamic Performance of Parabolic Dish Concentrator [1]      The estimated useful energy for one cycle of the designed PDSWH is given by q    use        I b  A a    The efficiency range of most solar concentrators is 40% - 60% (Magal,1993)    Avg value of solar beam radiation at Pune in first quarter of 2014 is 714 W/m 2      Hence q  use   = 0.55(average of 0.4 and 0.6) x 714 x 1.56 =604.75W    For four cycles total useful energy is Q use = 4 xq  use = 4 x 604.75 = 2419W Useful energy is also given by q  use      m    . w   C     pw   ( T w    T a)       .  I    D .  Aa    International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163   Volume 1 Issue 8 (September 2014 )   www.ijirae.com ______________________________________________________________________________________________________ © 2014, IJIRAE- All Rights Reserved Page -201 0   m    . w  =   I    D dish 2 = 0.13 litres per minute. 4  x  c   pw x ( T w    T a)   m    .   w  is also given by m    .   w = ρ w x Vw t Where t= time required to heat the water . ρw  at 30°c = 995.7 kg/m 3  Therefore t = 45 min to heat 6 liters of water. For four cycles total time required is =180 minutes to heat 24 liters of water. The energy, Pabs, absorbed by the absorber is obtained from:       Pabs   , P abs = n o x A a  x I D , Divide and multiply by n, we get   Aa  I  D      P abs = n o (nA a I D ) n    n o  = 0.65 (average of 0.6 and 0.7)    Also we know q    use        I  D  A a  put in equation we get,      P abs  = 0.65/0.55 q  use   =1.18   q  use = 1.18 x 604.75 = 714W  IV.   R ESULTS   The objectives of the present investigation may be stated as,      To understand theoretical analysis of parabolic dish concentrator.    To find out efficiency of concentrator.    To test by varying pitch of receiver and find out optimum receiver length.    To fabricate copper helical coil tube receiver of 0.22M diameter and length.    To compare performance of PDC with point focusing and line focusing Validation of Experimental Set up Testing was done during the summer and clear sky with cloud free days during the month of April 2014 for about seven days. The tests were taken between 10 am to 4 pm in data were taken on each hour for 7 hours. The k type thermocouple with digital indicator used to measure temperature. Table 1  Receiver temperature variation with Time- Results on 5 th  April 14 Time   T   a  ambient temperature  o C    T   g  receiver temperature  o C    10 am 32 90 11 am 32 115 12 am 34 130 1pm 35 145 2pm 34 170 3pm 33 150 4pm 32 130    International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163   Volume 1 Issue 8 (September 2014 )   www.ijirae.com ______________________________________________________________________________________________________ © 2014, IJIRAE- All Rights Reserved Page -202 Table 2  Temperature variation with mass flow rate in kg/sec Sr.No. Mass flow rate Kg/sec Temperature of receiver in 0 C 1 0.0013 140 2 0.0014 138 3 0.0015 136 4 0.0016 133 5 0.0017 130 6 0.0018 128 7 0.0019 125 Table 3  Comparison of Helical coil and cavity receiver Time P F concentrator temp( 0 C) LF concentrator temp.( 0 C) % Rise 10 am   58 101 57 11 am 66 120 55 12 am 72 140 52 1pm 78 155 50 2pm 80 185 43 3pm 86 176 48 4pm 60 145 41 Based on the results obtained during the test of PDC steam generator the temperature above 190 o C was recorded with the ambient temperature, the maximum value reaches at about 2.00 pm and temperature varies along the solar trace on the absorber tube .The average soar beam radiation measured during testing as 714 w/m 2 . From above three figure it is clear that the temperature increases up to 2pm after which it gradually decreases. 02040608010012014016018010:00 AM11:00 AM12:00 PM1:00 PM2:00 PM3:00 PM4:00 PM Receiver temp Vs Time Receiver TemperatureAmbiant Temperature

32.SPCS10097

Jul 23, 2017
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