Energy performance of a clay tiles Solar drying system

Abstract

Drying of solids is one of the most energy-intensive processes in different industries mainly in clay bricks and tiles manufacturing. The construction materials quality closely depends on the drying external and internal parameters and requires a deep analysis of different drying conditions such us air temperature, air humidity and air flow rate in relation with the particular properties of the considered raw material. In order to reduce the consumption of fossil fuels and greenhouse gas emissions in clay tiles manufacturing alternative energies have to be used in this industrial process either as a unique or supplemental source. Thanks to the high thermal conversion efficiency, solar energy is one of the most suitable green energy sources for industrial heat generation. In this paper a small-scale solar drying system of a clay tile sample has been designed under Fez's climatic conditions. The thermal performance of the considered solar dryer has been evaluated during the least sunny week of the year based on a dynamic simulation environment via TRNSYS software coupled to an external mathematical code estimating the moisture content in the clay tile sample during the drying time. Based on the required air outlet temperature and drying time for clay tile moisture removal process, an optimal configuration of small-scale solar drying system is proposed, with 6 m2 of high pressure evacuated tubes solar collectors, 200 liters of thermal storage tank, 3 m/s of air velocity, 1 kg/s and 0.5 kg/s of water flow, respectively, in solar loop and heat exchanger loop.