Evaluation of the Potential of Large Solar Heating Plants in Spain

An evaluation of Central Solar Heating Plants with Seasonal Storage in Spain has been performed with dynamic simulations built on TRNSYS. The model has been designed for several Spanish cities that are representative of the different climatic areas with a significant demand of thermal energy for heating. The system should cover the heating demand of 1000 apartments of 100 m2 in multifamily buildings with similar features, providing a solar fraction of about 50% without wasting solar heat in summer and without oversizing the seasonal storage tank. Climatic and specific demand data for each city have been used. The model simulates the solar collector field, pipe lines, heat exchangers, a seasonal storage tank, pumps, auxiliary boiler and auxiliary pieces of equipment needed in the model. The obtained results show that CSHPSS with a solar fraction of about 50% require in the case of Spain a relatively small Ratio Area of solar collectors versus heating Demand and a high Ratio of seasonal storage tank Volume versus solar collector Area. The estimated cost of the heat produced in CSHPSS with a solar fraction of 50% can be competitive with the heat cost of domestic heat boilers, which is a very common solution for heating in residential buildings in Spain. The obtained results show that CSHPSS represent an interesting and promising alternative for covering the heating demand in residential buildings in Spain.