Performance Test of Solar Assisted Solid Desiccant Dryer S. MISHA 1,2,* , S. MAT 1 , M. H. RUSLAN 1 , K. SOPIAN 1 , E. SALLEH 1 , M. A. M. ROSLI 1 1 Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia 2 Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia *suhaimimisha@utem.edu.my Abstract: - The solar assisted solid desiccant dryer was designed and developed to dry agricultural product. The experiment was carried out to study the performance of the component in the dryer system and drying air condition without load. The system can produce drying air at average temperature 52 o C under average solar radiation of 797 W/m 2 which is suitable for heat sensitive product to maintain the fresh color, taste and nutrient content. The collector efficiency, heat exchanger effectiveness 1 and 2 was 70%, 77% and 67%, respectively. The thermal, regeneration and dehumidification effectiveness was 48%, 29% and 6%, respectively. The poor performance of desiccant wheel may be improved by increasing the regeneration temperature above 65 o C. Some improvements are still required to improve the overall performance of the system such as decrease the regeneration air flow rate, increase electrical heater power and using direct connection from the solar collector to the dryer system. Key-Words: - Solar drying; desiccant drying; desiccant wheel 1 Introduction Depletion of fossil fuel and gas reserves, has encourages industries to find others alternative energy sources to cater the current demands. An alternative energy resource especially solar energy becomes more attractive because it available in abundant. Solar energy is a free energy and environmental friendly source of renewable energy. Some of the solar applications are drying of agricultural products, space heating, solar desalination, etc. In drying application generally, up to 70% of the life cycle cost of a convective dryer is due to energy used. Therefore, the use of an energy- efficient drying process is important even at a higher initial cost. Various types of solar drying systems for agricultural and marine products have been reviewed [1]. Solar drying system is one of the most attractive and promising applications of solar energy systems in tropical and subtropical countries. Drying process plays an important role in the preservation of agricultural products. The drying air heats the product and carries the water in the form of vapor away from the product being dried. The lower the humidity of hot air supplied to the drying chamber is, the better the drying rate, as the dry air can carry more moisture from the product surface. These parameters (i.e., heat, velocity, and humidity) must be addressed in designing a dryer system. Generally, increasing the temperature and velocity improves the drying performance. However, for heat-sensitive products, such as pharmaceutical and food products, high temperature decreases product quality. Therefore, drying at low temperature and humidity is required to maintain the fresh color of the product using the desiccant system [2]–[4]. Several advantages of using desiccant material in drying application have been discussed in detail by Misha et al. [5]. Desiccant materials work based on the principle of moisture transfer due to the difference of vapor pressure between the air and the desiccant [6]. The desiccant with low moisture content will adsorb moisture from air until its vapor pressure is in equilibrium with the air. The saturated desiccant must be heated to enable the desiccant to remove the moisture. Generally, using solid desiccant in the construction of a dryer is simpler than using liquid desiccant because handling solid desiccant is easier [5]. Solid desiccant systems are widely used in the form of rotary wheel beds for packing the desiccant materials. Narayanan et al [7] studied on the performance of three different designs of desiccant wheel. Results shows that the counter flow desiccant wheel (Fig. 1) has better dehumidification performance than parallel flow. Addition of axial cooling section can improve dehumidification performance further. Computer Applications in Environmental Sciences and Renewable Energy ISBN: 978-960-474-370-4 174