Development of small-scale low-cost methods of drying herbs and agricultural products

Herbs are characterised by different contents of biologically active substances, hence they are widely used in various branches of industry. Herb cultivation in East-Central Europe focuses on small-sized areas requiring machines and equipment adapted to the scale of production. The processing of herb plants involves drying, which is one of the most important stages of herb preservation, conditioning the right quality of the raw material. This article presents a short description of the methods for herb preservation and a classification of drying systems using solar energy and hot air. Looking for ways to assure the drying of the crops in unfavourable atmospheric conditions, variants of solar collectors with the biomass-powered furnace for heating drying air in driers of herbs have been invented. The solutions developed by authors of this paper to provide small-scale low-cost technological devices for the drying of herbs and specialty crops are also presented. The installations presented use hot air from solar radiation and heat generated from the combustion of biomass in the form of wood chips. These installations and equipment do not require an electricity supply. The elimination of natural drying through the use of drying chambers eliminates the unfavourable effect of ultraviolet radiation on the loss of essential oils. The drying installations and devices presented in this article are under patenting procedure.