Objetivo Development and construction of an inexpensive, cost-effective and self-sufficient greenhouse heating system using solar energy.The purpose of the project is to check the validity of existing experiments and theories in hydroponics, by means of a 845 m2 greenhouse, and establish applicational and thermal characteristics in relation with climate conditions.The ultimate aim of this practical experiment would be to upgrade remote and isolated sites which lack in both heating facilities and arable soil. Expected energy savings 62 MWh/yr, payback 3 years.Due to various problems met with the solar collectors, studies are underway to identify a natural which will be more robust.Tests are ongoing with polypropylene. Inspite of difficulties collector efficiencies of up to 60% were measured with :- energy savings : 65 MWh/year- percentage annual energy savings : 70% (for 845 m2 greenhouse and 44<198> latitude) 60% during the first experiemtnal year 70% during the second experiemntal year after improvement of the storage tank.At present tests are underway to improve the collector's performance and the system design.The project concerns a solar greenhouse suitable for growing aromatic and medicinal plants, tropical plants, pot plants and all plants adapted at thermical conditions in isolated regions.The installation consists of a 845 m2, 3-bay trussed greenhouse with double-wall EVA plastic roof and polyester vertical sidewalls.Natural ventilation is achieved by full-length roof openings actuated automatically according to the temperature inside the greenhouse.Soil heating is achieved by means of radiant mulch (CEA Patent) and 215 m2 of tunnel-type water solar collectors made from polyethylene. Two pumps and closed-circuit piping network circulate water from an 150 m3 hot water storage tank through the solar tunnels and back to the tank which is insulated with polyurathane foam and a layer of concrete. During the day, solar radiation heats the water as it is pumped through the lines of radiant mulch. The heated water is stored in the tank. At night, the water from the tank gives up its heat to the radiant mulch system to maintain the soil's temperature at an optimal level.The plants are grown in an artificial soil (hydroponic media) made of peat moss bags. Soil moisture is maintained by an automatic drip irrigation system, without pH or conductivity monitoring.In comparison with a conventionally heated greenhouse in the same location, the solar system is expected to achieve energy savings equivalent to 6,5 tonnes of fuel annually. Only during the 3 winter months will it need an additional source of energy in the form of an auxiliary heating system.During the summer, water in the storage may, if necessary be cooled by pumping it through the solar collectors at night. In this way the relatively cool water is used to reduce excessive greenhouse daytime temperatures. A complete measuring and acquisition system is planned for to obtain, throughout the operational phase of the installation, complete data on the physical parameters of the experiment including: solar radiation, wind speed and direction, outside and inside temperatures, soil temperatures, water temperature at the different stages of the flow cycle, water flow etc... Programa(s) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Tema(s) 6.2 - THERMAL Convocatoria de propuestas Data not available Régimen de financiación DEM - Demonstration contracts Coordinador COMMISSARIAT A L'ENERGIE ATOMIQUE (CEA) Aportación de la UE Sin datos Dirección LA BLANCHETTE P.O. BOX 111 26700 PIERRELATTE Francia Ver en el mapa Coste total Sin datos
