1146/2014, the European Union (EU) has set the maximum limit of residual AQ for tea as 0.02 mg/kg. To protect consumer health, through the regulation of commission no. An incomplete combustion process produces polycyclic aromatic hydrocarbons, which if distributed can increase the anthraquinone (AQ) residue in the tea leaves. Because this involves the process of burning solid fuels, the probability of incomplete combustion is extremely high. The most crucial stage in tea processing is the process of withering and drying, which uses firewood as the heat source.
Indonesia is one of the most abundant tea-producing and exporting countries globally. These antioxidants can help in avoiding various diseases, including reducing the risk of cancer and preventing heart disease. Tea contains antioxidants, which are very useful for the body. The Page mathematical model is the best model to represent the behavior of the tea leaves with this HPHE system.
For 100 g of fresh tea leaves, the heating energy produced ranges from 15.21 W to 45.07 W, meaning it can wither tea leaves from 80% (w.b.) to 54% (w.b.) in a variety of 11 h 56 min to only 49.6 min. The results show that the effectiveness of the HPHE varies from 66% to 79.59%. Each fin is made of aluminum with a thickness of 0.105 mm and a size of 76 × 345 mm 2. The heat pipe used has a length of 700 mm with an outer diameter of 10 mm. The HPHE used consists of 42 heat pipes and 181 fins. The geothermal fluid simulators use water, which is heated by heater and flowed by a pump. This study aims to develop and test a new concept for the direct use of low-temperature geothermal energy with a heat pipe heat exchanger (HPHE) for the withering of tea leaves as a solution for energy sources free from AQ. The content of AQ in tea leaves increases when there is incomplete combustion in the combustion of firewood for the energy source of withering and drying of tea leaves. The volume of Indonesian tea exports to the European Union (EU) decreased by 43% in 2014 because of the EU setting a maximum residue limit of anthraquinone (AQ) for tea as 0.02 mg/kg.