MOHD HAFIDZ RUSLAN 1 , AHMAD FUDHOLI 1* , MOHD. YUSOF OTHMAN 2 , MOHD SYAHRIMAN MOHD AZMI 2 , MUHAMMAD YAHYA 1 , AZAMI ZAHARIM 1 & KAMARUZZAMAN SOPIAN 1 1 Solar Energy Research Institute (SERI) 2 School of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia 43600 UKM Bangi, Selangor MALAYSIA Email: *fudholi.solarman@gmail.com , azami.zaharim@gmail.com , k.sopian@eng.ukm.my The solar collector is one of the vital components of the solar drying system. Conventional solar air collectors mainly consist of an absorber plate with a parallel plate forming a passage of air flow. The heat transfer for this type of solar collector is low which results in lower thermal efficiency. Hence, different modifications are suggested and applied to improve the heat transfer coefficient between the absorber plate and the air. These modifications include the used an extended heat transfer area, such as finned absorber. A solar dryer system suitable for agricultural products have been designed, constructed and evaluated under the Malaysia climate conditions. The main components of the system are double<pass solar collector with finned absorber, the blower, the auxiliary heater and the drying chamber. The solar drying system has been evaluated for drying the oil palm fronds. The initial and final moisture content of the fronds are 60% (wet basis) and 10% (product basis) respectively. The drying time is about of 22 hours at average solar radiation of about 557 W/m 2 and air flow rate 0.1278 kg/s. The collector, drying system and pick<up efficiencies were found to be 31, 19 and 67% respectively. : Double<pass solar collector, finned absorber, palm oil fronds, efficiency ! Malaysia is the world's largest producer and exporter of palm oil and accounts for more than 60% of global export. Palm oil is extracted from oil palm fruits in the mills. The waste products of oil palm mills are empty fruit bunches, fibers, shells and fronds. There are about 145 oil palm trees per hectare in Malaysia. About 25 pieces of fronds can be obtained from a single tree. The average weight of each frond is about 8 kg. Hence, about 200 kg of fronds can be obtained in a year per tree. Hence, about 30 tons of fronds can be produced in one hectare in a year. Some of the palm fronds have to be cut to facilitate the harvesting of the fruit bunches. The fronds can be converted in useful products. One way is to chip and then dry them to be used as feed stock for animal feed (Sopian et al., 2009). Malaysia lies entirely in the equatorial region. On average, Malaysia receives of 4.21 to 5.56 kWh/m 2 of solar radiation a year. Solar energy has been identified as one of the most potential alternative energy resources as Malaysia receives abundant sunshine all year long (Azhari et al., 2008). Many studies on the performance of solar drying system have been conducted in the Green Energy Technology Innovation Park, Universiti Kebangsaan Malaysia, such as solar assisted drying systems with V<groove solar collector (Eltief et al., 2007), the double<pass solar collector with integrated storage system (Supranto et al., 2008), the solar assisted dehumidification system for medicinal herbs (Yahya et al., 2008), solar chemical heat pump drying system (Ibrahim et al., 2009) and the photovoltaic thermal (PVT) collector system (Othman et al., 2008). Eltief et al. (2007) reported an analytical study of drying chamber performance of V<groove forced convective solar dryer. The efficiency of the system is increased if the drying chamber is well constructed and provided with good insulation. Supranto et al. (2008) developed sizing of solar assisted drying system for oil palm fronds. The result equation may be used in long time performance and cost analysis for drying system of oil palm fronds. These result correlations may be used for study of auxiliary solar drying system Recent Researches in Power Systems and Systems Science ISBN: 978-1-61804-041-1 143