Physical Principles involved in coffee roasting Using a Fresnel solar concentrator

Abstract

Considering that the sun is a great source of energy, it can be used to roast coffee beans in a sustainable way using solar concentrators. This study is based on a anidolic Fresnel solar concentrator with a unique design, with which it is possible to collect the energy from the sun in a roasting chamber, incorporated into a motor that rotates in order to roast the coffee beans in a homogeneous way. In this research, the physical principles (heat transfer, power, efficiency, among others) involved in coffee roasting are analyzed. Carrying out temperature measurement in the roasting chamber, ambient temperature, irradiance, and wind speed at different times of the day, in order to know how long it takes to roast a given mass of coffee. The results indicate that the solar concentrator under study is functional, since it reaches temperatures greater higher than 240 °C and the ideal temperature for roasting coffee is between 180°C and 240 °C. But for this, the irradiance must be at least 1,100 W/m2.