Heat Transfer and Pressure Drop Characteristics in a packed bed Solar Air Heater

AUTHOR(S):

TITLE

Heat Transfer and Pressure Drop Characteristics in a packed bed Solar Air Heater

ABSTRACT

In the present work an experimental setup has been designed and fabricated for the experimental investigations on a packed bed solar air heater under simulated conditions. Wire mesh screen matrices with different geometrical parameters have been used as packing element in the flow duct. Data pertaining to heat transfer and friction factor characteristics were collected for air flow rate ranging from 0.0101 to 0.0250 kg/s.m2 for five sets of matrices with varying geometrical parameters. The thermal efficiency of packed bed solar air heater was compared with that of a conventional solar heater. Enhancement in the thermal efficiency, of the order of 41.15 to 82.40% was obtained as compared to conventional smooth solar collector under similar operating conditions investigated in the present work. The effect of geometrical parameters (wire diameter, pitch, porosity and number of layers) of matrices on the heat transfer coefficient and pressure drop, which affect the thermal efficiency of the collector, has been discussed in detail.

KEYWORDS

Solar collector, packed bed, geometrical parameters, wire mesh, air heater, heat transfer

REFERENCES

[1] ASHRAE Standard, 193-77, Method of testing to determine the thermal performance of solar collectors, 1977.

[2] Bhatti, M.S. and Shah, R.k., Turbulent and transition convective heat transfer in ducts, Hand book of single phase convective heat transfer edited by Kakac, S., and Shah, R.K. and Aung, W., Wiley, New York, 1987

[3] Choudhury, C., Garg, H.P. and Prakash, J., Design studies of packed –bed solar air heaters, Energy Convers. Mgmt, 34(2), 125-138, 1993.

[4] Chiou, J. P., Wakil, M.M. and Duffie, J.A., A slit and expended aluminium foil matrix solar collector, Solar Energy 9(2), 73-80, 1965.

[5] Coppage, J.E. and London, A.L., Heat transfer and flow friction characteristics of porous media, Chem. Engg. Progress, 52(2), 57F-63F, 1956.

[6] Dhiman, P., Thakur, N.S. and Chauhan, S.R., Thermal and thermohydraulic performance of counter and parallel flow packed bed solar air heaters, Renewable Energy, 46, 259-268, 2012.

[7] Reddy, T.A. and Gupta, C.L., Generating application design data for solar heating systems, Solar Energy, 25, 527-530, 1980.

[8] Hamid, Y.H. and Beckman, W.A., Performance of air cooled radiatively heated screen matrices, Trans. ASME, J. Engineering for Power, 221-224, 1971.

[9] Hasatani, Chiou M. Itaya, Y. and Adachi, K. Heat transfer and thermal storage characteristics of optically semitransparent material packed-bed solar air heater, Current researches in heat and mass transfer, A Compendium and Festschrift for Prof. A. Ramachandran, ISHMT, Dept. of Mechanical Eng., IIT, Madras, India, 61-70, 1985.

[10] Mittal, M.K. and Varshney L., Optimal thermohydraulic performance of a wire meshed packed solar air heater, Solar Energy, 80, 1112-1120, 2006.

[11] Ozturk H.H. and Demirel, Y., Exergybased performance analysis of packed bed solar air heater, International Journal of Energy Research, 28, 423-432, 2004.

[12] Prasad, S.B., Saini, J.S. and Singh K.M., Investigation of heat transfer and friction characteristics of packed bed solar air heater using wire mesh as packing material, Solar Energy, 83, 773-783, 2009.

[13] Thakur, N.S., Saini J.S. and Solanki S.C., Heat transfer and friction factor correlations for packed bed solar air heater for a low porosity system, Solar Energy, 74, 319-329, 2003.

[14] Tong, L.S. and London, A.L., Heat transfer and flow friction characteristics of woven-screen and cross-rod matrixes, Trans. ASME, 79, 1558-1570, 1957.

[15] Varshney, L. and Saini, J.S., Heat transfer and friction factor correlations for rectangular solar air heater duct packed with wire mesh screen matrices, Solar Energy, 62(4), 255-262, 1998.

Cite this paper

L. Varshney, Rameshwar Kumar Singh. (2017) Heat Transfer and Pressure Drop Characteristics in a packed bed Solar Air Heater. International Journal of Mechanical Engineering, 2, 111-118