In the year 2000, a system that uses solar energy in combination with Aquifer Thermal Energy Storage (ATES) was being designed. Its aim was to conserve a major part of the oil and electricity used for heating or cooling the Cukurova University, Balcali Hospital in Adana, Turkey. The general objective of the system was to provide heating and cooling to the hospital by storing solar heat underground in summer and cold in winter. As the main source of cold energy, ventilation air at the hospital and surface water from the nearby Seyhan Lake was to be used.