Energy Analysis of Pid Controlled Heat Pump Dryer

Ilhan CEYLAN
DOI: 10.4236/eng.2009.13022                

Abstract

In this experimental study, a heat pump dryer was designed and manufactured, in which drying air temperature was controlled PID. Manufactured heat pump dryer was tested in drying kiwi, avocado and banana from among tropical fruits and energy and exergy analyses were made. Drying air temperature changed between 40 oC - 40.2 oC while drying the tropical fruits. Before the drying process in heat pump dryer, initial moisture contents were determined as 4.31 g water / g dry matter for kiwi, 1.51 g water / g dry matter for avocado and 4.71 g water / g dry matter for banana. Then tropical fruits were dried separately in heat pump dryer. Drying air temperature was kept unchanged with the error of +0.2 oC. Drying air velocity changed between 0.3 and 0.4 m/s in a period of 310 min. COPws of the heat pump dryer was calculated as 2.49 for kiwi, 2.47 for banana and 2.41 for avocado during the experiments. EUR changed between 13 % and 28 % for kiwi, 18% and 33% for avocado and 13% and 42% for banana in heat pump dryer.

Keywords

Tropical Fruit, Drying, Heat Pump Dryer, PID Control

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	?. Ceylan and H. Do?an, “Nem kontrollü kondenzasyonlu kereste kurutma f?r?n?,” II. Ulusal Ege Enerji Sempozyumu ve Sergisi., Dumlup?nar üniversitesi, Kütahya., Turkish, pp. 155–166, 2004.
[2]	M. Fatouh, A. B. Metwally, A. B. Helali, and M. H. Shedid, “Herbs drying using a heat pump dryer,” Energy Conversion and Management, Vol. 47, No. 15–16, pp. 2629–2643, 2006.
[3]	H. Ogura, N. Hamaguchi, H. Kage, and A. S. Mujumdar, “Energy and cost estimation for application of chemical heat pump dryer to industrial ceramics drying,” Drying Technology, Vol. 22, No. 1–2, pp. 307–323, 2004.
[4]	R. Queiroz, A. L. Gabas, and V. R. N. Telis, “Drying kinetics of tomato by using electric resistance and heat pump dryers,” Drying Technology, Vol. 22, No. 7, pp. 1603–1620, 2004.
[5]	K. J. Chua and S. K. Chou, “A modular approach to study the performance of a two- stage heat pump system for drying,” Applied Thermal Engineering, Vol. 25, No. 8–9, pp. 1363–1379, 2005.
[6]	S. Achariyaviriya, S. Sopanronnarit, and A. Terdyothin, “Mathematical model development and simulation of heat pump fruit dryer,” Drying Technology, Vol. 18, No. 1–2, pp. 479–491, 2000.
[7]	K. J. Chua, S. K. Chou, J. C. Ho, and M. N. A. Hawlader, “Heat pump drying: Recent developments and future trends,” Drying Technology, Vol. 20, No. 8, pp 1579– 1610, 2002.
[8]	M. N. A. Hawlader, C. O. Perera, M. Tian, and K. L. Yeo, “Drying of guava and papaya: Impact of different drying methods,” Drying Technology, Vol. 24, No. 1, pp. 77–87, 2006.
[9]	A. Midilli and H. Kucuk, “Energy and exergy analyses of solar drying process of pistachio,” Energy, Vol. 28, pp. 539–556, 2003.
[10]	Y. A. Cengel and M. A. Boles, “Thermodynamics: An engineering approach,” McGraw-Hill, New York, 1994.
[11]	X. Jia, P. Jolly, and S. Clemets, “Heat pump assisted continues drying,” Part 2: Simulation Results, International Journal of Energy Research, Vol. 14, pp. 771–782, 1990.
[12]	Y. A. Cengel and M. A. Boles, “Thermodynamics: An engineering approach,” Third Edition, McGraw-Hill, New York, pp. 1056, 1998.
[13]	E. L. Schmidt, K. Klocker, N. Flacke, and F. Steimle, “Applying the transcritical CO2 process to a drying heat pump,” International Journal of Refrigeration, Vol. 21, No. 3, pp. 202–211, 1998.
[14]	M. N. A. Hawlader, S. K. Chou, J. C. Ho, and K. J. Chua, “On the development of a heat pump dryer to maximise heat recevery,” in A. S. Mujumdar (Series Ed.), Proceedings of the 11th International Drying Symposium, Halkidiki, Greece, No. 19–22, pp. 616–623, August 1998.
[15]	A. Bejan, “Advanced engineering thermodynamics,” Wiley, New York, 1988.
[16]	O. Zuhal, “Testing of a heat-pump-assisted mechanical opener dryer,” Applied Thermal Engineering, Vol. 23, pp. 153–162, 2003.
[17]	I. Ceylan, M. Akta?, and H. Do?an, “Energy and exergy analysis of timber dryer assisted heat pump,” Applied Thermal Engineering, Vol. 27, pp. 216–222, 2007.