Development of heating cloth for frost protection in vineyards and fruit orchards

Protection of vineyards and orchards against late frosts is an important issue in many fruit growing areas around the world. Therefore, a demand exists for low cost, precise, and reliable methods of protection. A new technology enables common cotton fibers/yarns to work as a heating wire after their coating with special pyrrole polymers providing them with electro-conductivity. The objective of this research work was to apply this metal-free based technology for practical design of nets that could be used in vineyards or orchards as a frost protection method. The first step was testing the functionality and viability of these textiles under conditions of real vineyards/orchards environment. Yarns either with or without hydrophobic protection did not change substantially the surface resistance (viability) after 40 days exposition to outside conditions. Constructed heating cloths (nets) were further tested in frost simulated conditions in a vineyard. The influence of different voltages was assessed. Voltage of 60 V increased the temperature of net but not the temperature of protected leaf, whereas 90 V increased both the temperature of net and also of the protected leaf. Concerning the potential consumption and other practical issues, first results indicate the possibility of developing this system as an effective standalone frost protection measure in vineyards. To increase the efficiency, some changes of the construction and supplementing the system, e.g. with reflective cover cloth, will be considered.