EXPERIMENTAL EVALUATION OF HEAT LOSS FROM A MULTI-TUBE TRAPEZOIDAL CAVITY RECEIVER FOR A LINEAR FRESNEL SOLAR CONCENTRATOR CONSIDERING NATURAL AND FORCED CONVECTION CONDITIONS

2017 ◽  
Author(s):  
Selen Sousa ◽  
Alexandre Bittencourt de Sa ◽  
Victor César Pigozzo Filho ◽  
Júlio Passos
Keyword(s):  
Heat Loss ◽  
Forced Convection ◽  
Experimental Evaluation ◽  
Solar Concentrator

Using a Windbreak to Improve the Thermal Performance of a Flat Plate Solar Collector: A Feasibility Study

2011 ◽  
Author(s):  
Saeed Moaveni ◽  
Michael C. Watts
Keyword(s):  
Flat Plate ◽  
Heat Loss ◽  
Forced Convection ◽  
Thermal Performance ◽  
Solar Collector ◽  
Large Scale ◽  
Ambient Air ◽  
Absorber Plate ◽  
Wide Range ◽  
Flat Plate Solar Collector

During the past few decades, a wide range of studies have been performed to improve the performance of flat plate solar collectors by either reducing the heat loss from a collector or by increasing the amount of solar radiation absorbed by the absorber plate. Examples of these studies include adding transparent honeycomb to fill the air gap between the glazing and absorber plate to reduce convective heat loss, replacing the air in the gap by other gases such as Argon, Krypton, Xenon and Carbon Dioxide, or adding a chemical coating such as Copper Oxide to increase absorbtance and reduce the emittance of the absorber plate. While these methods improve the collector’s efficiency, they focus primarily on limiting the natural convection that occurs in the collector cavity, or on improving the optical properties of the absorber or glazing. None of these studies have addressed the problem of heat loss due to forced convection to the surrounding ambient air in any detail. Yet, research has shown that forced convection will contribute significantly to the heat loss from a collector. Windbreaks have traditionally been used to direct wind to protect farmland, and to direct wind drifts and sand dunes. Windbreaks also have been shown to provide protection for homes from winter winds which result in reduced heating costs for buildings. While windbreaks have been traditionally used for large scale applications, there is reason to believe that similar benefits can be expected for scaled down applications such as adding a windbreak along side of a flat-plate solar collector. In this paper, we examine the feasibility of using a windbreak to provide a flat plate solar collector protection from the wind in order to improve its performance. A series of experiments were performed wherein the thermal performance of two flat-plate collectors — one without a windbreaker and one with a windbreaker — were measured. The results of these experiments are reported in this paper and the need for further studies to explore different windbreak configurations is discussed.

scholarly journals The Effect of Different Absorber Configurations On The Exergy and The Energy of Parabolic Solar Dish

2020 ◽  
Vol 7 (3) ◽  
pp. 1-13
Author(s):  
A'laa Taghi Al-Azawi ◽  
Ali A. F. Al Hamadani
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Tracking System ◽  
Open Cavity ◽  
Solar Concentrator ◽  
International Conference ◽  
National University ◽  
Parabolic Dish

Abstract— The solar energy is the most important type of energy. The parabolic dish solar collector (PDSC) is the best type among other solar collectors because it is always tracking the sun movement. The exergy and the energy performances of a PDS were analyzed experimentally and numerically. The effect of different coil geometries and different mass flow rates of heat transfer fluid (HTF) were investigated. The PDS has parabolic dish and receiver with diameter (1.5) m and (0.2) m respectively. Concentration ratio is 56.25. The parabolic polar dish was supported by a tracking system with two axes. The types of the copper absorber were used which are: (spiral –helical) coil (SHC) and spiral-conical coil (SCC). The results showed that the useful energy and thermal efficiency are varying with solar radiation variation. The useful energy varying between (480-765) W for (SHC), the thermal efficiency varying between (35.2-39.8) % for (SHC). Exergy efficiency varying between (6.9 –8.6) %. It was shown that the higher values of useful energy for (spiral – helical) absorber was 0.1L/min flow rate. REFERENCES  1. T. Taumoefolau , K. Lovegrove ," An Experimental Study of Natural Convection Heat Loss from a Solar Concentrator Cavity Receiver at Varying Orientation. ", Australian National University,, Canberra ACT 0200 AUSTRALIA.2002  2. S. PAITOONSURIKARN and K. LOVEGROVE," On the Study of Convection Loss from Open Cavity Receivers in Solar Paraboloidal Dish Applications ", Australian National University Canberra ACT 0200, AUSTRALIA, pp 154,155,2003  3. Soteris A. Kalogirou*,"Solar thermal collectors and applications", Higher Technical Institute, Progress in Energy and Combustion Science 30 (2004) 231–295, pp237, 240, 241, 2004  4. M. Prakash, S.B. Kedare, J.K. Nayak," Investigations on heat losses from a solar cavity receiver", Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India,2008.  5. Shiva Gorjian1, Barat Ghobadian1, Teymour Tavakkoli Hashjin1, and Ahmad Banak ,"Thermal performance of a Point-focus Solar Steam Generating System ", 21st Annual International Conference on Mechanical Engineering-ISME201 7-9 May, 2013, School of Mechanical Eng., K.N.Toosi University, Tehran, Iran ,1ISME2013-1195,2013  6. Kailash Karunakaran1 Hyacinth J Kennady2 ,"Thermal Analysis of Parabolic Dish Snow Melting Device " ,International Journal for Research in Technological Studies| Vol. 1, Issue 3, February 2014 | ISSN (online): 2348-1439,2014  7. Charles-Alexis Asselineau, Ehsan Abbasi, John Pye "Open cavity receiver geometry influence on radiative losses" Australian National University (ANU), Canberra, ACT 0200 Australia. Solar2014: The 52nd Annual Conference of the Australian Solar Council 2014  8. Vahid Madadi, Touraj Tavakoli and Amir Rahimi First and second thermodynamic law analyses applied to a solar dish collector" DOI 10.1515/jnet-2014-0023 | J. Non-Equilib. Thermodyn. 2014; 39 (4):183–197  9. Yaseen. H. Mahmood , Mayadah K h. Ghaffar " Design of Solar dish concentration by using MATLAB program and Calculation of geometrical concentration parameters and heat transfer" , University of Tikrit , Tikrit , Iraq, Tikrit Journal of Pure Science 20 (4) ISSN: 1813 – 1662, 2015.  10. Vanita Thakkar, Ankush Doshi, Akshaykumar Rana "Performance Analysis Methodology for Parabolic Dish Solar Concentrators for Process Heating Using Thermic Fluid IOSR", Journal of Mechanical and Civil Engineering (IOSR-JMCE) eISSN: 2278-1684,p-ISSN: 2320-334X, Volume 12, Issue 1 Ver. II (Jan- Feb. 2015), PP 101-114  11. Saša R. pavlovi, Evangelos A. bellos, Velimir P. Stefanovi, Christos Tzivanidis and Zoran M. Stamenkovi "Design, Simulation ,and Optimiztion Of A Solar Dish Collector with spiral coil absorber ", , Nis, Serbia, thermal SCIENCE, Vol. 20, No. 4, pp. 1387-1397 1387,2016  12. Flávia V. Barbosa, João L. Afonso, Filipe B. Rodrigues, and José C. F. Teixeir," Development of a solar concentrator with tracking system", University of Minho,Guimarães, 4800-058, Portugal2016  13. O. López, A. Arenas, and A. Baños"Convective Heat Loss Analysis of a Cavity Receiver for a Solar Concentrator" International Conference on Renewable Energies and Power Quality (ICREPQ’17)Malaga (Spain), 4th to 6th April, 2017 ,ISSN 2172-038 X, No.15 April 2017 RE&PQJ, Vol.1, No.15, April 2017  14. D.R.Rajendran,E.GanapathySundaram,P.Jawahar "Experimental Studies on the Thermal Performance of a Parabolic Dish Solar Receiver with the Heat Transfer Fluids Sic water Nano Fluid and Water", Journal of Thermal Science Vol.26,  15. Muhammad Shoaib, Muhammad , Jameel Kabbir Ali ,Muhammad Usman1, Abdul Hannan " Analysis of thermal performance of parabolic dish collectors having different reflective" ,NFC institute of engineering &fertilizer research ,2018 .  16. Sasa PAVLOVIC, Evangelos BELLOS, Velimir STEFANOVIC ,Christos TZIVANIDIS " EXPERIMENTAL AND NUMERICAL INVESTIGATION OF A SOLAR DISH COLLECTOR WITH SPIRAL ABSORBER" A CTA TECHNICA CORVINIENSIS – Bulletin of Engineering Tome XI [2018] .   

Heat loss of a trapezoidal cavity absorber for a linear Fresnel reflecting solar concentrator

2012 ◽  
Vol 39 (1) ◽  
pp. 198-206 ◽  
Author(s):  
S. Flores Larsen ◽  
M. Altamirano ◽  
A. Hernández
Keyword(s):  
Heat Loss ◽  
Solar Concentrator

Plates of the Dinosaur Stegosaurus: Forced Convection Heat Loss Fins?

Science ◽  
1976 ◽  
Vol 192 (4244) ◽  
pp. 1123-1125 ◽  
Author(s):  
J. O. FARLOW ◽  
C. V. THOMPSON ◽  
D. E. ROSNER
Keyword(s):  
Heat Loss ◽  
Forced Convection ◽  
Convection Heat

Experimental investigation of the comparison of compound parabolic concentrator and ordinary heat pipe-type solar concentrator

2018 ◽  
Vol 29 (5) ◽  
pp. 770-783
Author(s):  
Fahim Ullah ◽  
Mansoor K Khattak ◽  
Kang Min
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Heat Loss ◽  
Thermal Performance ◽  
Performance Comparison ◽  
Loss Coefficient ◽  
Fluid Temperature ◽  
Solar Concentrator ◽  
Average Heat ◽  
Compound Parabolic Concentrator

In this research study, we have compared between the two different concentrators with the flat absorber plate receiver of the compound parabolic concentrator heat pipe solar concentrator and ordinary heat pipe flat plate solar concentrator. For the reproduction of solar radiation in the experiment, iodine tungsten lamp was used. Thermal performance comparison of the two types of solar concentrator under different simulating radiation intensity conditions was carried out with including the fluid temperature, instantaneous efficiency, average efficiency, and average heat loss coefficient. The results of the experiment indicate that the compound parabolic concentrator heat pipe-type solar concentrator not only increased the fluid temperature and instantaneous efficiency but also decreased the average heat loss coefficient as compared with the ordinary heat pipe flat plate solar concentrator. It was noticed from the experimental results that the efficiency of compound parabolic heat pipe solar concentrator was higher than ordinary heat pipe solar concentrator up to 6 and 10°C with the light intensity, that is I = 679 W/m2 and I = 892 W/m2, respectively. From the results, it was concluded that the using of compound parabolic heat pipe solar concentrator increased the thermal performance of solar concentrator.

Constructal Theory and the Optimization of Finned Arrays

2003 ◽  
Author(s):  
A. D. Kraus
Keyword(s):  
Heat Loss ◽  
Forced Convection ◽  
Constructal Theory ◽  
Input Admittance ◽  
Rectangular Profile

Existing expressions for the optimization of individual fins of rectangular profile are reviewed and a new expression that relates the tip admittance to the input admittance is derived. A procedure for finding the optimum longitudinal fin of rectangular profile with tip heat loss is provided and this procedure is illustrated with an example of an array for a forced convection example.

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