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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #323126

Research Project: New Sustainable Processing Technologies to Produce Healthy, Value-Added Foods from Specialty Crops

Location: Healthy Processed Foods Research

Title: Design of solar thermal dryers for 24-hour food drying processes

item Alleyne, Fatima
item Milczarek, Rebecca

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/6/2015
Publication Date: 11/13/2015
Citation: Alleyne, F.S., Milczarek, R.R. 2015. Design of solar thermal dryers for 24-hour food drying processes. In: Proceedings of the 2015 COMSOL Conference in Boston. COMSOL Conference 2015, October 7-9, 2015, Boston, Massachusetts. 2015 COMSOL Conference 2015, October 7-9, 2015, Boston, Massachusetts. 2015.

Interpretive Summary: Solar drying has the major limitation of being available only during daylight hours. One way to extend the drying day would be to include heat storage in the solar dryer, in the form of special materials called “phase change materials.” Phase change materials must reach a minimum temperature to start storing heat. In this study, simulations have been employed to assess the temperature profiles for multi-layer solar thermal drying cabinets fabricated using materials with different optical properties. Optical properties of the transparent cover significantly influences the internal temperature and therefore drying time, with the shortest times observed for systems designed with a high absorptivity value and low emissivity value. This study will guide the design of more efficient solar dryers for fruit and vegetable crops.

Technical Abstract: Solar drying is a method that has been adopted for many years as a food preservation method. To this date, significant advancements have been made in this field with the adoption of a multitude of solar thermal dryer designs for single-layer and multi-layer drying of fruit and vegetables e.g. cabinet, tunnel and chimney dryers. However, the ability to dry overnight, thus drying over a 24-hour period, to enhance efficiency and productivity, has continued to plague the agricultural community. One solution is the incorporation of phase change materials as heat storage mechanisms. Under the appropriate conditions, phase change materials can be an invaluable resource in food drying. In this work we have utilized the COMSOL 5.0 Heat Transfer Module to simulate the temperature profiles for solar cabinet dryers, composed of materials with different optical properties and under various conditions, to identify suitable phase change materials for solar thermal dryers.