Desidratador de produtos naturais via ar aquecido operante por meio de energia solar fotovoltaica

Abstract

The both restoration and optimization of the heated air, photovoltaic solar energy-operated, natural products dehydrator have been done, and both sensors and actuators were installed. Four new fuses were purchased, and the drying chamber sealing rubber was repaired. As for the equipment optimization, most of the electrical components which make up the generation system were stored in a power board, the photovoltaic modules pair have been installed on the platform located above the laboratory, it has been acquired an exhaust fan (with a nozzle adaptation), a dimmer, a new inverter and a new charge controller, in addition to a side hole opening in the drying chamber, for better humid air exit. After these activities, both the sensors and actuators used in the experiments have been acquired. The microcontroller used to obtain and store data is on a board compatible with Arduino Mega 2560. Three dry bulb temperature and relative humidity sensors (DHT22) and an electrical current sensor (ACS712) have been purchased and connected to the board, as well as a micro SD card module and a memory card. The code which obtains and stores the data has been elaborated. A J-type thermocouple was also acquired. After carrying out these activities, the experiments have begun, using three trays to dehydrate both sliced apples and bananas. Each type of fruit has been dehydrated for fourteen hours, one fruit at a time. The fruits have been both photographed and weighed before dehydration. After fourteen hours, the fruits have been photographed and weighed again, obtaining a mass percentage reduction in the lower, intermediate and upper trays of 72%, 79% and 78% for apple and 66%, 62% and 63 % for banana, respectively. The DHT22 1 sensor has provided average values of dry bulb temperature and ambient air relative humidity of 25.8 °C and 43.9%, for apples, and 26.0 °C and 42.9%, for bananas. For both fruits, graphs of dry bulb temperature and relative humidity have been plotted at the chamber both entrance and exit, as a function of dehydration time. The average effective values of electric current intensity and dissipated power (both in the electrical resistance) of 1.070 A and 235.34 W (for apple) and 1.054 A and 231.95 W (for banana) were also obtained. Finally, it has been concluded that the objectives were achieved, that the equipment worked properly (after restoration and optimization); that the fruits lost most of their total water mass (after 14 h of dehydration) and that there was psychrometric equilibrium in the drying chamber.