Final report by the ECOVELAS task force: improving the candle-heating system currently used to protect stone fruit crops in the Guadalquivir Valley from frost

As part of the ECOVELAS project, a study has been carried out to improve the candle-heating system currently used to protect stone fruit crops in the Guadalquivir Valley from frost: by reducing the formation of smoke ‘caps’ and increasing the thermal efficiency of the candles. To this end, the impact of fuel composition on smoke formation and heating efficiency was studied, as well as the effect of candle placement in the field on fluid movement in the air layer near the ground. Several field trials were carried out using two types of tins (one containing petroleum paraffin and the other animal stearin). Each type of candle was placed in a trial area where several thermometers were set up, and monitoring was carried out for 12 hours over several nights with frost.