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View references (68) Short-rotation coppice (SRC) represents an important source of wood biomass. Many uncertainties create barriers to farmers establishing SRC plantations, especially under Mediterranean climate conditions. In this study, five species and respective genotypes were analyzed. The five species were Fraxinus angustifolia, Robinia pseudoacacia, Salix alba, Populus nigra (Limatola), and Populus × euroamericana, with the genotypes of the latter being Grimminge, Vesten, Hoogvorst, Muur. For the plantations studied, two different harvesting systems were replicated: the single machine pass, or cut-and-chip (CC); and the double machine pass, for which the tree are cut first, then chipped later (chip of stored trees CS). In the CC, fresh trees were harvested and chipped by Claas Jaguar 880. In the CS, dry trees were chipped by Farmi Forest CH 260. Within the same site, in climatic conditions and low-input management, the best result in terms of biomass yield was obtained from the black poplar Limatola. Both wood typologies and harvesting systems affected the chip quality. The disk chipper, when working on dried biomass, produced lower quality chips than the other chipping device in terms of particle size. In the chips obtained, there was an increase in the number of chips classified as being “larger size” and “oversized”, and a decrease in the percentage of those classified as “accept” (45–3 mm fraction). The chips obtained from dried trees were of better energy quality compared with the same biomass obtained from the fresh trees in terms of heating value and ash content. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

More than 0.7 million ton of oil equivalent is the total requirement for thermal energy in the Italian greenhouse vegetable industry, derived mostly from fossil fuels, which corresponds to 2 Mt CO2 emissions. The technology of wood biomass system is a good candidate for heating greenhouses, since this resource is considered as 'greenhouse gas' (GHG) neutral when converted to heat, excluding the GHG generation during harvesting, transportation, and pre-processing of raw materials. Besides, the CO2 enrichment in greenhouses from the exhaust gas of a biomass heating system can bring benefits for greenhouse production, along with optimal management strategies to reduce fuel consumption. Unfortunately, CO2 enrichment from the exhaust gas of biomass boilers is still challenging and expensive, considering that wood biomass boilers generate a higher volume of particulate matters (PM) and ash emissions than other fossil fuels. However, wet scrubbers and other recent flue gas conditioning devices could help to reduce costs and make this process more feasible. In the Italian peninsula, the power energy load for greenhouses heating was estimated to be between 30 and 175 W m-2, while the thermal energy consumption varies between 21 to 546 kWh m-2 year-1 according with internal air temperature and climatic zones. In general, the total cost of a heating system with boiler, loading system, accumulator, control system and safety, installation, and heat delivering can vary from a maximum of 1400 € kW-1 for systems with power up to 100 kW, 600-800 € kW-1 for power over 100 kW, to a minimum of 400 € kW-1 for systems with power over 1000 kW. Thus, a techno-economic assessment is highly recommended to ascertain the economic feasibility of wood biomass boilers for the greenhouse industry, as related to the economic incentives by the National Decree of 28 December 2012, so-called "White Certifies". © 2017 ISHS.

This paper deals with an interesting application of different technologies to greenhouse heating systems. First, biomass boilers is a mature and affordable technology, showing high efficiency and long lasting devices. As wood biomass is considered as GHG neutral when converted to heat, it is logical to think about its application to greenhouse heating. Second, the thermally activated heat pumps, and more specifically the absorption heat pump, has reached a mature technology, as well. If the thermally activated heat pumps are coupled with short and long term heat storage, this can enhance the overall efficiency of the system. As greenhouse radiant, floor and bench heating systems can exploit low grade thermal energy, and these interconnections generate virtuous circles for the environmental impact reduction related to greenhouse heating systems. © 2016, SRAC - Societatea Romana Pentru Asigurarea Calitatii. All rights reserved.