Analysis of intermittent infrared drying using heat recovery with a novel control methodology

Abstract

Drying is one of the most energy consuming process. By using automatic control systems in the industry, a higher quality and energy efficient drying is achieved. There are two main periods in drying process, the constant rate period and the falling rate period. In the falling rate period, it becomes difficult to evaporate water from the product, and this results in high specific energy consumption values and low energy efficiency values. In this study, apple slices were dried in an intermittent infrared dryer with two new developed drying methodologies as a solution to this problem (Model 2 and 3). An Arduino based automatic control system was used for Model 2 and Model 3. Developed models were compared with conventional experiments (Model 1). With Model 2, a constant drying rate was achieved independently of the moisture content. With Model 3, 57% shorter drying time compared to Model 2 and 16% less energy consumption compared to Model 1 was provided. Also using of the Model 3 the energy efficiency increased as 50% and the specific energy consumption decreased as 48% compared to Model 1. This study offers a solution with high efficiency in industrial usage. Practical Applications Conventional dryers have low energy efficiency and high specific energy consumption. With two novel drying methodologies developed within the scope of this study, a reduction of 16% in energy consumption and increase of 50% in energy efficiency were observed as an alternative to conventional drying. In addition, a constant drying rate was achieved independently of the moisture content. These drying methodologies offer an applicable solution for drying process with high energy efficiency in industrial food drying systems. Thus, it is foreseen to decrease the energy consumption and increase the efficiency in the drying industry, which constitutes a large part of the industrial energy consumption.