Experimental Studies of Drying Pineapple with An Active Indirect Solar Tunnel Dryer in Malaysia

Abstract

Abundant sunshine and tropical climate of Malaysia have made pineapple a suitable fruit to be grown in this country. However, to have longer shelf-life, lighter weight for transportation and less storage space, drying of pineapple has been a common preservation method in this country. Open-sun drying used to be most common method of preserving agricultural products. Nevertheless, due to the disadvantages of open sun drying method, solar drying technology has become an alternative method of drying vegetables, fruits, spices, herbs etc. The main purpose of this paper is to evaluate the performance of active solar tunnel dryer (ASTD) for drying sliced pineapples. The air circulation system in this dryer is based on forced convection system. In active solar tunnel dryer inlet airflow temperature was gained by corrugated absorber plate. During the experiment minimum, maximum and average of absorber thermal efficiency were 13.1% and 24.4%, and 19.8 % respectively. The inlet temperature range was between 26˚C to 38˚C, the escalated temperature range was between 34˚C to 75˚C on the absorber outlet. Relative humidity (RH) experienced changes due to irradiance intensity, the RH reduced when passed through the absorber plate. The average inlet humidity was 54% while average outlet humidity was 36%. During 9 hours of drying process, pineapple moisture content reduced from 89% to 12.5% and its weight decreased from 5 kg to 0.6 2kg. The peak sun hours were 5.7 hours, and loading density was 1.51 kg/m2 .