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30120140504023 2

  1. 1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME 194 COMPARATIVE ANALYSIS OF PERFORMANCE OF SALT GRADIENT SOLAR POND WITH CONVENTIONAL (FLAT) AND CORRUGATED BOTTOM Prof. Sunil Kumar¹ Prof. (Dr.) S.K.Singh2 Asst. Prof. Prof. & Director Mechanical Engineering Department B.I.T Sindri, Dhanbad, Jharkhand, India B.I.T Sindri, Dhanbad, Jharkhand, India ABSTRACT The purpose of this analysis is the development of salt gradient solar pond design to improve the performance of solar pond. The study of previous treatment of internal reflection is considered by dividing the spectrum into a finite no. of spectral wavelength bands. To evaluate the performance of solar pond various method of augmentation are included. Such as based on depth cold sea water as heat sink, auxiliary heat source at high temperature, waste heat, fossil fuels and biomass fuels. In this paper the heat extraction from the lower convective zone or storage zone of salt gradient solar pond with corrugated bottom is investigated with the aim of increasing the overall efficiency of collecting solar radiation. A theoretical analysis is conducted to obtain expression for the variation of temperature with depth of solar pond. The efficiency of the solar ponds depends on thickness of storage zone, temp of delivered heat, the analysis suggests that heat extraction from the storage zone has potential to increase the overall efficiency of solar pond delivering heat at a relatively high temp up to 50% compared with the conventional solar pond the potential gain in efficiency using storage zone heat extraction is attributed to the storage zone that can be achieved with this method. The effects of system and operating parameters of the soar ponds like area enhancement factor (β), heat extraction rate, heat capacity rate, depth of the pond on the temp distribution and efficiency have been developed. Keywords: SGSP, Heat Extraction Rate, Area Enhancement Factor, Heat Capacity Rate, Temp Distribution, Salinity Profile, Temp Profile. INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) ISSN 0976 – 6340 (Print) ISSN 0976 – 6359 (Online) Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (2014): 7.5377 (Calculated by GISI) www.jifactor.com IJMET © I A E M E
  2. 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME 195 INTRODUCTION Solar pond is a low cost means to collect and store solar energy in the form of high density salt water. It consists of three main layers. The top layer Upper Convective Zone (UCZ) of thickness varying between 0.15 to 0.30 m which is cold and close to atmospheric temp and has low salt concentration. The bottom layer Lower Convective Zone (LCZ) of thickness varying between 1.0 to 2.0 m is hot approximate 70° to 95° and very salty and close to saturation temp. These two layers are separated by imported gradient zone known as Non Convective Zone (NCZ) of thickness varying between 1.0 to 1.5 m. where salt content increases with depth. Water in this layer cannot rise because the water below it has higher salt content and is heaver therefore convective motion are hindered and heat transfer from hot to cold can only happen through conduction. Non convective layer acts as transparent insulator permitting sunlight to be trapped in the hot bottom layer from which useful heat is withdrawn. Fig 1 Fig 2 METHODOLOGY An experimental study on the development of the performance of the salt gradient solar pond a small prototype salt gradient solar pond was executed nearby heat engine laboratory in the Department of Mechanical Engineering at B.I.T. Sindri, Dhanbad. The body of the pond heaving rectangular dimension of 6x4x2 feet. The material used is water proof 19mm thick ply. For the lining of the pond thermocol of 1̎ thick has been used. To cover the thermocol another lining of 5mm black fiber has been provided to absorb heat from solar radiation and retain heat within the body. The maximum temperature attained in the storage zone was 48°C carrying out a difference in temp between the bottom (33°C) and surface (30°C) in the clear sunny day. Several methods for enhancement of thermal performance of salt gradient solar pond have been proposed and investigated by a number of investigators. One of the most promising means of improving the thermal performance conventional SGSP is to increase the bottom surface area by making the surface corrugated (wavy/v shaped) which increases the heat transfer capacity to the water and consequently
  3. 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME 196 increases the performance of the solar pond. The most significant design modification for increasing the solar pond thermal efficiency is to increase the stability of the surface layer. The effect of the various parameters on the thermal performance considering the stability criteria in SGSP are studied and the result of the steady state indicate that the thickness of the non convective zone has a significant effect on the performance of the salt gradient solar pond. In present work an analytical model of SGSP with corrugated bottom surface has been developed in order to analyze the effect of various parameters like depth of the solar pond, heat capacity rate, heat extraction rate, mass flow rate on temperature distribution and efficiency. EXPERIMENTS AND RESULTS A schematic diagram of salt gradient solar pond with corrugated bottom surface is shown in above fig. Corrugated bottom has been constructed by providing Aluminum sheets. Salts like magnesium chloride (MgCl2), sodium chloride (NaCl) or sodium nitrate (NaNO3) are dissolved in the water. Concentration varies from 20% to 30% at the bottom to almost zero at the top surface. Salt concentration gradient will disappear over a period of the salt. At the same time concentrated brine is added at the bottom of the solar pond. The amount of the salt required for this purpose is about 50 gm/m2 /day which are large quantity when it is considered on an annual basis. For this reason the normal practice is to recycle the salt by evaporating the saline water runoff from the surface in an adjacent evaporation pond. Fig 3: Salt gradient solar pond without transparent glass
  4. 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME 197 Fig 4: Salt gradient solar pond with transparent glass Fig 5: gradient solar pond with transparent glass and booster mirror
  5. 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online), Volume 5, Issue 4, April (2014), pp. 194-198 © IAEME 198 CONCLUSION 1. The results show that there is significant influence of the area enhancement factor on thermal performance of corrugated/ v shaped solar pond. At constant value of heat capacity rate (q=0 w/m2 ) the percentage enhancement in the temperature efficiency have been found to be 21.16% and 22.42% respectively. These results due to the fact that increase in heat transfer surface area increases the heat transfer capability of the working water and consequently increase the temp and efficiency of the solar pond. 2. It has been observed that efficiency of the solar pond is strong function of the heat capacity rate and heat extraction rate. The efficiency of the solar pond increases exponentially with an increase in heat capacity rate i.e. it decreases slowly with increase in heat capacity rate. 3. The result shows that the efficiency of the storage zone of the solar pond increases linearly with increase in heat extraction rate for various values of heat capacity rate. 4. It has been observed that temp of the storage zone decreases with an increase in heat capacity rate at all values of heat extraction rate. 5. It has been observed for area enhancement factor the temp of the solar pond almost remains constant in the upper convective zone, whereas temp increases linearly with the increasing depth I Non convective zone. The max temp attains in the lower convictive zone. REFERENCE 1. M.N.A Hawaldar & B.J Brinkworth. “An analysis of the Non convictive solar pond”, solar energy volume 27 No 3 page 195-204, 1981. 2. Taboor H. “solar pond Renewed”, solar energy 27, 181-191, 1981. 3. Rubin H. and Bemporad G.A “Analysis of turbulent flow in thermal layers of a advanced solar pond”, solar energy 43, 25-33, 1989. 4. Rubin H. and Bemporad G.A “The advanced solar pond” Basic theoretical aspects, solar energy 43, 33-34, 1989. 5. Rubin H. keren. Y and Bemporad G.A “Feasibility of advanced solar pond according to osder method. 6. Mehmet karakilick I.et al “Performance investigation of solar pond”, Applied thermal engineering volume 26, Issue 7, pages 727-735, 2006. 7. IEEE, International conference on smart structure and system March 28 & 29, 2013. 8. Comparison of thermal behavior of solar ponds with flat or conventional and corrugated bottom, jsrp.org, volume 3, 2013. 9. Hamza.al.tahaineh, Mahndoh Al.B.usoul, “Numerical investigation of the effect of salt gradient solar pond dimension on the pond performance and energy storage, volume 3, no. 10, 2013. 10. Anirban Sur and Dr.Randip.K.Das,, “Review on Solar Adsorption Refrigeration Cycle”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 1, Issue 1, 2010, pp. 190 - 226, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. 11. Prakash Kumar Sahu and Prof.Dr.A.C.Tiwari, “Implement of Solar Energy in Thermal Power Station for Increase Sensible Heat of Makeup Water for Save the Conventional Energy, A Review & Case Study”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 3, 2012, pp. 180 - 186, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.

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