Analysis of a new drying chamber for heat pump mint leaves dryer. (13th July 2017)

• Record Type: Journal Article
• Authors: Aktaş, Mustafa; Khanlari, Ataollah; Aktekeli, Burak; Amini, Ali
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 28(2017)
• Page Start: 18034
• Page End: 18044
• Publication Date: 2017-07-13
• Subjects: Drying -- Mint leaves -- Heat recovery -- Cylindrical drying chamber; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.03.007
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Drying is an energy intensive and time consuming process, so reducing amount of demanded energy and drying time are important issues for drying technology. The main aim of this paper is to analyze the drying characteristics of mint leaves in a new cylindrical form of drying chamber at low drying air temperature and by emphasizing on energy analysis. The dryer consists of air source heat pump system, air to air heat recovery unit and proportional temperature controller. Experiments were performed at 2, 2.5 and 3 m/s air velocities and at 35 °C cabin inlet air temperature. Mint leaves were dried from 9 g water/g dry matter to 0.1 g water/g dry matter. Designed drying chamber, with three stainless steel cylinders in circular nested form, has a positive effect for drying technology. This system has some advantages such as: drying of product by accessing a uniform air flow and preventing spread of light weight samples like mint leaves over drying system. Calculations based on experimental data show that in the best case, by consuming 3.164 kWh energy in a heat pump with 3.94 coefficients of performance, 4.56 kWh energy had been gained by heat recovery unit. Average 48% of energy was saved by means of heat recovery unit. Effective moisture diffusivity values varied from 3.50E−11 to 5.88E−11 for mint leaves. Highlights: A new drying chamber design for mint leaves drying. Energy efficient heat pump drying with heat recovery unit. 48% of energy was saved by means of heat recovery unit. Obtaining homogenous dried product via cylindrical chamber.