Experimental Investigation of a Solar Greenhouse Dryer Using Fiber Plastic Cover to Reduce the Moisture Content of Refuse Derived Fuel in an Indonesian Cement Industry

Refuse Derived Fuel (RDF) is a potential alternative energy made from municipal solid waste (MSW). RDF could partially substitute coal in industries that use combustion equipment, for example in cement manufacturing industries. The optimal moisture content for solid fuel is around 10-20%. However, RDF that supplied in one of Indonesian cement industries reached moisture content almost 30%. A solar dryer has been built and tested to reduce the moisture content of RDF. Its parts were a greenhouse type tunnel drying unit with fiber plastic cover and electrical axial fans. In this experiment, the effect of three fan modes on the thermal efficiency were also investigated. The modes were operating one fan, two fans, and without fan. The solar dryer had dimensions of 2 m x 1.5 m x 0.8 m (length x width x height). The mass of RDF was 20 kg. The efficiency was calculated using the measured experimental data, i.e. environment temperature, room temperature, air velocity, solar irradiation, and relative humidity. The result revealed that the lowest moisture content produced by the dryer reached to 14.75%. Furthermore, the thermal efficiency could increase up to about 17.07% by using two fans mode.