The performance of a solar tent dryer equipped with a solar chimney, as against that of open sun drying, was examined in the drying of cassava. An initial no-load trial was done, followed by trials with the dryer loaded with cassava. One drying trial was performed with the crops on the lower shelf, another with the crops on the upper shelf and a third trial with the dryer loaded on both the lower and upper shelves. In each drying trial, some cassava were also dried in the open sun which results were compared to that of the dryer. In the no-load process, the temperature inside the dryer increased with height due to thermo-syphon effects. But this trend was distorted by the evaporation of moisture from the crops during the drying processes, especially at the initial stages. About 75% to 80% of the drying process occurred within the first two days and nights of the drying periods. The open-sun drying was faster at the initial stages of drying, especially when the crops were on the lower shelf or the dryer was fully loaded. But the performance of the dryer overtook that of the open sun drying at later stages of drying. Thus, the dryer started more slowly but finished earlier than the open-sun drying. The best drying performance was observed when the crops were high up the dryer, though only a small amount of crops could be allowed at this height due to the design of the dryer.

1 Afriyie, J. K., Nazha, M. A. A., Rajakaruna, H. and Forson, F. K. (2009). Experimental investigations of a chimney-dependent Solar Crop Dryer. Renewable Energy 34 (1), 217–222.
2Afriyie, J. K., Nazha, M. A. A., Rajakaruna, H. and Forson, F.K., (2011). Simulation and optimisation of the ventilation in a chimney-dependent Solar Crop Dryer. Solar Energy 85, 1560-1573.
3Afriyie, J. K. and Bart-Plange, A. (2012). Performance Investigation of a chimney-dependent Solar Crop Dryer for different inlet areas with a fixed outlet area. International Scholarly Research Network ISRN Renewable Energy, Article ID 194359, 9 pages doi:10.5402/2012/194359
4Afriyie, J. K., Nazha, M. A. A., Rajakaruna, H. and Forson, F. K. (2013). Mathematical modelling and validation of the drying process in a chimney-dependent Solar Crop Dryer. Energy Conversion and Management 67, 103-116.
5Andrew W. (2002). Cassava utilization, storage, and small scale processing. Natural resource institute, Chatham maritime. UK, 14, 270-290.
6Belessiotis V. and Delyannis E. (2011). Solar drying. Solar Energy 85, 1665-1691
7Cansee, S., Watyotha, C., Thivavarnvongs, T., Uriyapongson, J. and Varith, J. (2008). Effects of temperature and concentration on thermal properties of cassava starch solutions. Songklanakarin J. Sci. Technol. 30 (3), 405-411
8Chantawong, P., Hirunlabh, J., Zeghmati, B., Khedari, J., Teekasap, S. and Win, M. M. (2006). Investigation on thermal performance of glazed solar chimney walls. Solar Energy 80, 288–297.
9Chen, Z. D., Bandopadhayay, P., Halldorsson, J., Byrjalsen, C., Heiselberg, P. and Li, Y. (2003). An experimental investigation of a solar chimney model with uniform wall heat flux. Building and Environment, 38, 893-906.
10Ekechukwu O. V. (1999a). Review of solar-energy drying systems I: an overview of drying principles and theory. Energy Conversion and Management, 40, 593-613.
11Ekechukwu, O. V. (1999b). Review of solar-energy drying systems II: an overview of solar drying technology. Energy Conversion and Management, 40, 616–655.
12Ekechukwu, O. V. and Norton, B. (1997). Design and measured performance of a solar chimney for natural circulation solar energy dryers. Renewable Energy, 10 (4), 81–90.
13Ferreira, A. G., Maia, C. B., Cortez, M. F. B., and Valle, R. M. (2008). Technical feasibility assessment of a solar chimney for food drying. Solar Energy 82, 198–205.
14Incropera F. P., De Witt D. P., Bergman T. L. and Lavine, A. S. (2007). Introduction to heat transfer, 5th edition, John Wiley & Sons Inc., Hoboken, New Jersey.
15Jain, D. and Tiwari, G. N. (2004). Effect of greenhouse on crop drying under natural and forced convection I: Evaluation of convective mass transfer coefficient. Energy Conversion and Management, 45, 765-783.
16Lola, A., Lawrence, O. O. and Adefunke, B. (2012). Effect of delayed processing on some physico-chemical properties of cassava starch. American Journal of Food and Nutrition Print; ISSN 2157-0167, Online: ISSN 2157-1317, doi:10.5251/ajfn.2012.2.2.31.36 © 2012, ScienceHuβ, http://www.scihub.org/AJFN
17Mujumdar, A. S. (1997). Drying fundamentals. In: Baker, C. G. J. (Editor) Industrial Drying of foods, Blackie Academy and Professional, ISBN 0-7514-0384-9, 7-30.
18Olufayo, A. A. and Ogunkunle, O. J. (1996). Natural drying of cassava chips in the humid zone of Nigeria. Bioresource Technology, 58, 89–91.
19Ong, K. S. (2003). A mathematical model of a solar chimney. Renewable Energy 28, 1047-1060.
20Ong, K. S. and Chow, C.C. (2003). Performance of a solar chimney. Solar Energy, 74, 1-17.
21Onyenwoke, C. A. and Simonyan, K. J. (2014). Cassava post-harvest processing and storage in Nigeria: A review. African Journal of Agricultural Research, 9 (53) 3853-3863.
22Okos, M. R., Narsimhan G., Singh R. K. and Weitnauer, A. C. (1992). Food Dehydration. In: Heldman, D. R., Lund D. B., (Editors) Handbook of Food Engineering. Marcel Dekker, Inc, New York, Basel, Hong Kong, 437-562
23Owusu-Baah K, Workshop on ECOWAS policy (2004). (Accessed from the Ghana Homepage: http://www.ghaweb.com on 30/11/2004)
24Pongsawatmanit, R., Temsiripong, T., Ikeda, S. and Nishinari, K. (2006). Influence of tamarind seed xyloglucan on rheological properties and thermal stability of tapioca starch. Journal of Food Engineering. 77 (1), 41-50.
25Rogers, G. F. C. and Mayhew, Y. R. (1992). Engineering Thermodynamics, Work and Heat Transfer, 4th Edition, ISBN 0-582-04566-5
26Sharma, A., Chen, C. R. and Lan, N. V. (2009). Solar-energy drying systems: A review. Renewable and Sustainable Energy Reviews 13, 1185–1210
27Singh, S., Singh, P. P., Dhaliwal, S. S. (2004). Multi-shelf portable dryer. Renewable Energy, 29, 753-765.
28Stone, G.D., 2002. Both Sides Now. Current Anthropology 43(4):611-630.

@article{Afriyie05031007,
title = " Field Drying of Cassava in a Solar Tent Dryer equipped with a Solar Chimney ",
journal = "International Journal of Science and Engineering Applications (IJSEA)",
volume = "5",
number = "3",
pages = "161 - 173",
year = "2016",
author = " J. K. Afriyie, O-W. Achaw ,K. A. Aikins, C. K. K. Sekyere, A. Bart-Plange ",
}