ISHS Acta Horticulturae 893: International Symposium on High Technology for Greenhouse Systems: GreenSys2009
CONVERSION OF A HIGH-DEMANDING THERMAL-ENERGY LEVEL GREENHOUSE FROM CONVENTIONAL OIL HEATING SYSTEM TO WOOD-BASED RENEWABLE SOURCES HEATING SYSTEM FOR TROPICAL PLANTS PRODUCTION IN MEDITERRANEAN CONDITIONS |
| Authors: | C. Bisaglia, E. Romano, M. Cutini, F. Nucci |
| Keywords: | alternative energy use, energy saving, greenhouses, heating system, internal microclimate, logistic |
| DOI: | 10.17660/ActaHortic.2011.893.40 |
| Abstract:
Ornamental plant production under protected conditions is one of the most energy-consuming sector of agriculture. In Mediterranean regions, growers are faced with rising costs for microclimate control. The situation is worse in high-quality cultivations as tropical flowers where the reduction of energy inputs is not always sufficient to restore profitability. Also investing in new low-energy consuming greenhouses is not always achievable due to the high initial costs. The optional strategy presented is to investigate cheaper fuels. A study case was analysed considering a commercial installation located in Liguria Region, Italy, specialized in moth orchids (Phalaenopsis spp.) production. The greenhouse plant was very traditional with 20-year-old steel, single glass gutter-connected frame, 3 m maximum height and 4 124 m2 total floor area articulated in six productive units (PU). The heating schedule was programmed for 12 months year-1 heating. Three temperature regimes were adopted (15-18°C; 18-20°C and 23-26°C); five PU were provided with thermal screens. The conventional heating system was based on a central diesel oil boiler 1.16 MWt power and an under-bench hot water pipes system. The oil consumption resulted 126,000 kg year-1 ranging from 1,680 kg month-1 (July) and 18,480 kg month-1 (January) with a specific yearly cost of 23.6 to 27.3 € m-2. Any investment focused in oil saving was evaluated unfeasible in comparison with the use of a cheaper fuel without changing the frame structure. A biomass boiler 1.39 MWt power was added to the conventional one. A pre-insulated thermal pipe with reduced number of pipe joints was used to deliver hot water inside the greenhouses. The biomass boiler was fed both with wood chips coming from certified forests (FSC, Forest Stewardship Council) management standard located at distances <40 km and sawdust pellets lowering the yearly specific cost to expected value of 14-16 € m-2. Detailed cost analysis and management aspects are provided. | |
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