. Materials and methods
The system has been designed, constructed and installed in the Univesidad Politecnica de Chiapas. The system has one volumetric of 0.55 m3 and with capacity of dried maxim of 5 kg. The dehydrator has air inlet in the low part and an exit in the top part. The exit has the characteristic of be opening or be closed depending on the internal temperature of the system. General scheme of the system is present in Fig. 1. On top of the frame was mounted, covered with a glass plate. It is know that glass is transparent practically in all regions of wavelengths important for thermal energy [13]. Thermometers and hygrometer measured the input and output air temperature and humidity. Instruments are necessary for the optimum dehydration. The characteristic of the sensor are: DS18B20 digital thermometer provides 9 bits t o12 bits Celsius temperature measurements were used. It has an operating temperature range of -55 qC to +125 qC and is accurate to r 0.5 qC. DHT11 humidity sensor with measurement range 20-90% Rh and humidity accuracy r 5% RH too. These sensors are connected with an Arduino Uno that is a microcontroller board based on the ATmega328. This board acquires the sign of the sensors and save in a memory. And finally the system has three positions to provide the maximum irradiation of the collector plane in different seasons of a year.