The closed loop system
In the framework of the GREEN PUMP project, we had initially conceived an open loop system, aiming to exploit the local very shallow aquifer, in order to keep operational cost low and to maximize energy savings. Actually, basements of all adjacent buildings have to be protected by small groundwater pumps, which start pumping, when the water table exceeds a certain level. While the level of the groundwater table has been confirmed, the capacity of the aquifer proved smaller than anticipated.
For this reason, we have decided to construct a vertical closed loop system in order to feed one of the two heat pumps that have been installed. This system will consist of 8 boreholes, each 100 m deep. In each borehole a U-shaped geo-heat exchanger will be installed. Then the boreholes will be filled with suitable grout. The boreholes will be constructed next to the Division of Hydraulics and Environmental Engineering. The distances between them will be at least 6 m. The heads of the boreholes will be connected with the heat pump by a suitable pipe network. A centrifugal pump will be also installed for the circulation of the refrigerant through the geo-heat exchanger.
