Conventional drying methods can be improved by utilizing geothermal energy and the addition of Zeolite-A as an absorbent from the synthesis of Kaolin, which has abundant resources in Indonesia. The use of geothermal energy for fossil energy substitution results in the development of more sustainable and safer environmentally, while the use of Kaolin as absorbent will increase economic value and reduce the export of raw materials in Indonesia. This research was conducted to study the effect of adding Zeolite-A to the heat pipe heat exchanger (HPHE) system that utilizes geothermal energy to the performance of tea withering. As a source of geothermal fluid, a water heater with a capacity of 9000 Watts and hot water flowed with a pump were used. The HPHE used was constructed of 42 pcs of heat pipes and 181 pcs of the fin. The heat pipe used had a length of 700 mm with an outer diameter of 10 mm, the fluid worked in the heat pipe using water with a filling ratio of 50%.The fin was made of aluminum with a thickness of 0.105 mm with a size of 76 x 345 mm. The results showed that the effectiveness of HPHE varied from 64.825% to 78.363%. The Henderson and Pabis model was the best model to represent the behavior of tea leaves using Zeolite- A, and the Page model for the withering of tea leaves without Zeolite-A. With the addition of Zeolite- A, the speed of tea leaves withering increased by about 18%. In addition to being environmentally friendly, the use of geothermal energy can be an alternative energy substitution for drying tea that uses firewood which is harmful to health because it becomes the source of anthraquinone (AQ) as a cause of cancer in humans.
Keywords: Heat Pipe, Low-Temperature Geothermal, Kaolin, Zeolite-A, Anthraquinone, Tea Leaves, Withering, Drying.