Feasibility study of a geothermal energy system for indoor swimming pool in Campi Flegrei area

Technologies based on a renewable energy source can be an optimal solution to the heating of a swimming pool, which can be very expensive in terms of energy demand. In this work, the energy demand of a swimming pool located in Campi Flegrei area (Naples surroundings, Italy) is supplied by a geothermal plant. Campi Flegrei are a very advantageous location for a geothermal plant installation at either low or medium temperature. Temperature gradient of the ground is usually equal to 0.03 K/m, but in the Campi Flegrei area it is significantly larger. With the exception of hottest areas, which are characterized by steaming ground, thermal springs and fumarolic emissions, a good value is equal to about 0.2 K/m. The swimming pool is 25.0 m long, 17.0 m wide and it has an average depth of 1.80 m. Building thermal loads are evaluated by means TRNSYS®. The energy demand for water heating is evaluated taking into account heat losses from pool surface and for water evaporation. The geothermal system is designed taking into account the geological and hydro-geological characteristics of the site, the characteristics of the geothermal plant and energy conversion system. A cost analysis is also presented which shows that the whole setup is economically satisfactory.