Optimal design of geothermal-solar greenhouses for the minimisation of fossil fuel consumption

Greece has a significant geothermal potential with high enthalpy fields in the Aegean Sea region and low enthalpy fields scattered in specific locations of the country that has not been sufficiently exploited yet. One promising application would be the use of geothermal energy for greenhouse heating. The present work proposes an integrated and analytical methodology for the design of a geothermal-solar greenhouse that minimises the fossil fuels consumption and replaces it with geothermal energy. To that effect, the system modules are modelled analytically and the energy balances of all the system components are formulated. The resulting model is solved and the main design parameters are determined, in order to minimise the entire installation heat losses and the electric energy consumption. A case study is presented where the proposed methodology has been applied with interesting results concerning the technical and financial efficiency of the system. (c) 2005 Elsevier Ltd. All rights reserved.