To avoid excessive thermal stress in the exchanger it requires a gradual and progressive process of preheating. This heating must be done using the HTF daily and maintaining the temperature reached during the day over hours without solar radiation.
     If the star up has to be done in winter or during low radiation periods, an auxiliary HTF heating system needs to be installed. At all times the heat exchanger was controlled by six temperature sensors. Thus the thermal gradients and temperature drops that could damage it were properly controlled