Design of a Geothermal Energy Dryer for Beans and Grains Drying in Kamojang Geothermal Field, Indonesia

Abstract

Indonesia is a country rich in geothermal energy. Of approximately 20,000 MWe energy potential, only about 850 MW has been utilized for electricity purposes. There are not many direct utilization activities for various purposes have been implemented. This paper discusses a design of a geothermal dryer for beans and grains drying that will be implemented in Kamojang geothermal field, West Java, Indonesia. Geothermal fluid waste from a Kamojang well of approximately 160°C will be used to supply the equipment. The heat will be extracted to produce a room drying temperature, for which coffee bean will be used as an experimental grain to be dried. A tube-bank heat exchanger has been designed, consisting of 1-meter-staggered pipes of 2 inches (50.1mm) outer diameter. An air blower from one side produces air flow of varying velocity to flow heated air into a drying room on the other side. With a geothermal fluid flow containing a heat transfer rate of 1000 W and various air flow velocity of 4 to 9 m/s, the HE design could produce an output drying temperature of 45.5 to 40.6°C and drying energy (heat) produced in the drying room of about 41.5 to 68.9 kW/m length of the heat exchanger. Depending on the bean’s humidity, the drying time has to be set accordingly.