The Ecovelas operating group- which is made up of Asociafruit, AICIA (Higher Technical School of Engineering of the University of Seville), SAT Royal, and Primor Fruit, SA and leading Andalusian companies in the cultivation of stone fruit trees- was established in 2016 with the objective of improving the anti-frost control system in the cultivation of stone fruit in the Vega del Guadalquivir. They aimed at doing so using anti-frost candles and developing new fuel/candles that allow maintaining the heating efficiency of the current system while reducing emissions and the formation of smoke 'berets', and increasing the system's thermal efficiency.
To achieve this, they have studied the impact that the fuel's composition has on the formation of smoke and its heating efficiency, as well as the effect that the placement of the candles in the field has on the fluid's movement in the layer of air near the ground.
They also tested mixing various additives to the base material currently used to make candles for frost protection systems (paraffin and stearin). Several types of wicks were also studied with the aim of reducing the smoke from this element. They also evaluated several lighting solutions to avoid the use of external liquid fuels, as well as improvements that make it possible to dispense with the use of containers.
The field trials were carried out in a peach farm in January / February 2020, using two types of containers, one with petroleum paraffin, and the other with animal stearin previously tested in the laboratory.
Both types of candles were notably better than the previously used sawdust/paraffin mixture blocks, and were very effective in terms of their crop protection effect, as they warm and maintain the minimum temperature at a level that avoids or minimizes damage due to frost. The paraffin, however, produced a large amount of black smoke. Meanwhile, the stearin presented the improvement that had already been observed in the laboratory, confirming that it is a more environmentally suitable type of candle.
The project has been co-financed through the European Funds for Rural Development, with the participation of the Junta de Andalucía through the Ministry of Agriculture, Fisheries, and Sustainable Development as well as the Ministry of Agriculture, Fisheries and Food. For more information please visit www.gopasociafruit.com.