Thin Layer Modeling of Tom Yum Herbs in Vacuum Heat Pump Dryer

Abstract

Thin layer vacuum heat pump drying experiments were conducted to determine drying models for Tom Yum herbs (chili, lemon grass, kaffir lime leaf and galangal slice). The drying experiments were conducted in a vacuum heat pump dryer at a constant drying pressure of 0.2 bars and drying temperatures ranging from 50 °C to 65 °C. The experimental results were fitted to a number of well-known thin layer drying models and it was found, for the range of drying temperature tested, that the Midilli model is the best model for all Tom Yum herbs. To account for the influence of drying temperature, the constants and coefficients of model were formulated as functions of the drying temperature. Statistical tests of agreement between the model and experimental results were performed by determining the coefficient of determination (R²) , reduced chi-square (χ²) and root mean square error (RMSE). It was found that the model is in very good agreement with the experimental results.

Effect of air velocity on kinetics of thin layer carrot pomace drying

“…Drying characteristics of apple pomace (Sun et al, 2007), grape seeds (Roberts et al, 2008), cocoa (Hii et al, 2009), garlic (Fernando et al, 2008), leafy vegetables (Sobukola et al, 2007) and tom-yum herbs (Artnaseaw et al, 2010) have been reported. Hot air oven drying of carrot pomace was reported by Upadhyay et al (2008) without considering effect of air velocity.…”

Review on low‐temperature heat pump drying applications in food industry: Cooling with dehumidification drying method

“…It can be done either in lower (−20°C to 45°C) or higher (45°C to +110°C) temperatures (Figure 1). Solar, microwave, infrared, and radio frequency HP systems require higher temperatures while chemical, vacuum and cooling with dehumidified HP systems operate at relatively low temperatures (Artnaseaw, Theerakulpisut, & Benjapiyaporn, 2010; Goh et al, 2011; Yadav et al, 2016; Yohana et al, 2018). Cooling with dehumidifier HP can be assisted with solar power, coulomb force, single or dual stage heat pumps, and so on (Goh et al, 2011; Minea, 2015).…”