Geothermal energy application in Campi Flegrei Area: The case study of a swimming pool building

Swimming pool is an important direct use application of low and medium temperature geothermal fluids. Campi Flegrei area is a location particularly advantageous for a geothermal plant installation at either low or medium temperature. Below the depth where ground temperature is dependent on ambient one, temperature gradient is typically equal to 0.03 K/m, but at Campi Flegrei it is much larger. With the exception of hottest areas, characterized by steaming ground, thermal springs and fumarolic emissions, a good value is about 0.2 K/m. In this paper, the design of a geothermal energy plant for air conditioning and heating of water in swimming pool building will be discussed. The building occupies a surface of 2185 m2 of area and 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®. Energy requirement 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. Finally, a cost analysis will be also presented.