Abstract:
The energy audit in a traditional medicine factory was conducted in this research. The current total energy consumption, which consist of charcoal 84%, diesel oil 11.7%, and clectricity 4.3%, is 627.3 GJ per month. The main product, which is for both local consumption and export, is the bar fonn of dried traditional medicine made from herb. In the process, drying which is heated by burning charcoal consumes the highest energy. Thus in this research the energy conseuration was focused on drying process. There arc 84 cabinet dryers, cach with 15 stories and capacity of 100 kg, is operated as batch process with natural ventilation. Typical drying period, in which the product moisture is reduced from 182-298 %d.b. to 3-5%d.b. is 45 hours per batch. The existing cabinet dryer consumes 33 kg of charcoal per batch or 66.4 kg of water evap. per GJ. From energy balance, it can be indicated that the major causes of energy loss are incomplete combustion and flue gas loss. The input fuel was adjusted to improve the drying efficiency. The results showed that based on the final inoisturc content of the product (less than 8%) thc fuel input of thc drycr could bc rcduccd to 24 kg /batch or 93.9 kg of water evap. per GJ. Based on the charcoal price of 6 baht/kg, average daily operation of 25 dryers and 300 dayslyr., the total energy saving was about 405,000 baht/yr.(2 x 10' kJ/yr. or 27%) The adjusting of inlet and outlet air channels is not practical since the final moisture of the product was too high.