A Study on Performance Evaluation of Tea Dryers

Abstract

HighlightsThis study used data normalization, radar chart and weighting difference analysis to compare the performances of four types of tea dryers in terms of drying efficiency, energy, costs, qualities, and total efficiency.The electro-thermal dryers were more energy-saving and environment friendly.The vacuum drum dryer has the potential for useful application in high quality tea drying. Abstract. Tea dryers are essential equipment for tea manufacturers whereby, the hot-air tea drying machines, such as multiple-layer conveyor dryer (MLD), electric hot-air dryer (HAD), and low-humidity dryer (LHD), are commonly used. The vacuum drum dryer (VDD), a new type of tea dryer, has the potential to improve the drying quality and efficiency. Hence, it is necessary to assess its performance in comparison with the other three dryers to facilitate its application in the tea industry. This study used data normalization, radar chart, and weighting difference analysis to compare the performance of these four dryers in terms of drying efficiency, energy, costs, qualities, and total efficiency. The evaluation results indicated that the investment cost of the HAD was the lowest among all, followed by LHD and MLD, while the VDD was the highest. In terms of the drying quality, the opposite trend was observed in which the VDD gave the best performance, and followed by LHD, MLD, and HAD. For the rating of total efficiency, HAD outperformed VDD and LHD, where the lowest total efficiency was attained by the MLD. Considering the equal weighting of cost and quality, it can be concluded that HAD showed the best performance while MLD was the worst. Different requirements for cost and qualities affect the final evaluation of tea dryers. The electro-thermal dryers were more energy-saving and environment friendly than the fuel dryer. The VDD has better performance in terms of drying rate and qualities. Despite its energy consumption and equipment costs are higher, it still has the potential for useful application in high-quality tea drying. The continuous effort of researchers and dryer manufacturers in reducing the input costs and enhancing the benefits can improve the energy consumption and machinery cost of VDD. Keywords: Dryer, Performance evaluation, Radar chart, Tea.