Energy consumption of the wood size reduction processes with employment of a low-power machines with various cutting mechanisms

The article presents results of research on commercially used cutting mechanisms of low-power (about 10 kW) wood size reduction machines driven by small engines. The energy consumed was determined based on work demand, showing that two-cylinder cutting mechanism consumes less energy than disc cutting mechanism and drum cutting mechanism when wood size reduction various species of wood, within the cross-section range from 10 × 10 mm to 50 × 50 mm. The main application of the tested machines is the reduction of branch volume when maintaining the infrastructure of urban green areas, in order to facilitate their transport. The average increase in energy consumption required for the size reduction of a single 2-m-long timber beam relative to the most energy-efficient mechanism (two-cylinder cutting mechanism) may range from 369% to 478%, while the average energy consumed during 1 h of continuous wood size reduction machines operation may increase relative to the least energy-efficient mechanism from 80% to 188%. The average productivity when reducing the size of the wood of the tested machines depending on the cutting mechanism ranges from 0.47 tons/h to 0.06 tons/h. The greatest productivity is characterized by the two-cylindrical mechanism cutting 0.88 tons/h.