Enhancing the performance of conventional coffee beans drying with low-temperature geothermal energy by applying HPHE: An experimental study

Abstract

The unpredictable weather in Indonesia results in a less effective conventional coffee beans drying process, which usually uses solar energy as a heat source. This experiment aimed to examine the performance of the coffee beans drying using low-temperature geothermal energy (LTGE) with solar energy as the energy source. Heat pipe heat exchanger, which consists of 42 straight heat pipes with staggered configuration, was used to extract the LTGE. The heat pipes have 700 mm length, 10 mm outside diameter with a filling ratio of 50%, and added by 181 pieces of aluminum with a dimension size of 76 mm × 345 mm × 0.105 mm as fins. LTGE was simulated by using water that is heated by three heaters and flowed by a pump. Meanwhile, to simulate the drying process with conventional methods, a system of solar air collectors made of polyurethane sheets with a thickness of 20 mm and dimensions of length × width × height = 160 cm × 76 cm × 10 cm, respectively, was used in this study. Zinc galvalume sheet with 0.3 mm thickness was installed and coated by the black doff color throughout the inner of the container wall. The result showed that the drying process with LTGE and solar energy is faster than with solar energy or geothermal energy only. The drying coffee beans using the hybrid system can speed up the drying coffee beans time by about 23% faster than the solar energy only.

Enhancing Cooling Efficiency in Data Centers: An Evaluation of Heat Pipe Design in Air Ducts

“…This demonstrates the ability of heat pipes to transfer heat more rapidly and effectively. Gunawan et al [9] highlighted that the hybrid system, combining solar heat with a heat pipe heat exchanger for drying coffee beans, accelerates the drying process by about 23% compared to relying solely on solar energy. Similarly, Hakim et al [10] asserted that the incorporation of heat pipes significantly influences the precooling and reheating processes in HVAC systems, increasing the coefficient of performance (COP) by 39.9% compared to HVAC systems without heat pipes.…”