Obiettivo Threefold: to design, build and monitor the performance of two new concept1,000 m2 solar greenhouses fitted with passive thermosyphon air solar heating systems (designed according to the principles enunciated by Prof. A O. BARRA), to demonstrate the extent of energy savings achieved in each (estimated at 45 TOE/y) and to determine the potential for their commercial exploitation. Payback is estimated at 9. 8 years. For other projects using similar "BARRA" systems see SE/00574/83/UK and SE/00662/83/IT.The construction of the "Barra" greenhouse is completed.The assembling system has been optimized so that it is not necessary to use specialized workers to build a greenhouse.The useful surface for the agricultural activities is equal to 800 sqm. The greenhouse is in operation and is monitored all the the year permitting the evaluation of both summer and winter performance.The "UK" greenhouse is in operation and the first monitoring results are available. The auxiliary heating during the period Oct. 1987 to March 1988 was in average about 1350 kWh/day, with an average external ambient air temperature of 6 deg. C. During that time the heating controls were set at approximately 17 deg. C. during day time and 15 deg. C. during night time. The ventilation control was set at 22 deg. C. Plant desease reduced due to the increased, movement of air into greenhouse caused by the thermosyphon panels.One greenhouse will be built in Italy, the other in the UK. Design will correspond as near as possible to standard current commercial design of glass cladding on an aluminium/galvanised steel frame since this is most acceptable to the horticultural industry.A number of features are not standard commercial items:- the floor and sub-floor heat store- solar thermosyphons attached to the structure- built-in monitoring equipmentThe Barra system is one of air operation and free convection utilizing a solar convector of small thermal capacity, mounted vertically and coupled to the soil mass by underground air ducts. It has vertical solar chimneys and insulation on the north facade, and will provide the following:- air circulation to avoid heat stratification- underground storage to avoid over heating and obtain lower temperature savings (higher night temperature)- reduction of glazed area with lower solar gain- increase in collecting surface, especially in areas of higher than 40 degrees latitudeThe UK system consists of vertical solar thermosyphon matt black aluminium absorber plate panels (234 m2 total area) connected to a sub-floor heat store. The absorber plate has air channels formed by internal glazing and insulation. These are open at the top to discharge warm air directly into the greenhouse and have a direct connection at the bottom into the floor heat store. The greenhouse floor of hollow concrete blocks provides uninterupted air ducts and thermal mass for heat storage. The thermosyphon effect created by the panels circulates air through the greenhouse and into the storage ducts.Thermal screens drawn at eaves level will further enhance the use of stored heat. Savings in auxiliary conventional energy will also from greater utilization of solar energy at night, the effective increase of collecting surface area and additional insulation afforded by the north wall. A solar energy loss of 10%-20% is envisaged.The greenhouses will be fitted with fully automatic and controlled auxiliary heating and ventilating systems. Temperature sensors and solarimeters will be located in various positions throughout.The system is patented in Italy for domestic and public sector applications and a patent is being taken out in the UK. Programma(i) 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 Argomento(i) 6.2 - THERMAL Invito a presentare proposte Data not available Meccanismo di finanziamento DEM - Demonstration contracts Coordinatore WIMPEY LABORATORIES LTD Contributo UE Nessun dato Indirizzo BEACONSFIELD ROAD HAYES UB4 OLS Regno Unito Mostra sulla mappa Costo totale Nessun dato
