The PAT Energy Booster, a New Device for the Energy Recovery and Hydraulic Control in Water Supply Systems: Preliminary Experimental Tests

The energy efficiency of water supply systems is usually very low. They are affected by a high rate of water leakage with a significant loss in terms of the energy that is embedded in the lost water flow. Furthermore, the strategy to reduce the water loss frequently involves pressure reduction with a further decrease in energy efficiency. Several solutions have been proposed in the literature to reduce the pressure in the water distribution networks and recover the hydraulic energy, such as special turbines or pumps as turbines (PATs). Despite the positive aspects related to the use of such devices, the high installation costs, together with the limited hydraulic control capacity and the small power availability, limited the diffusion of such devices among the water utilities. A new device is proposed herein, which consists of two submersible PATs inserted into a booster cylinder. The high control capacity, together with the small production and installation costs, makes this technology very promising. The device has been installed in the Hydro Energy Lab of the CeSMA of the University of Naples and the first experimental results on its behavior are presented herein. A slight difference arises between the performance booster curves and the bare curves provided by the manufacturer due to measurement errors as well as to the presence of head loss within the system. Nevertheless, the energy efficiency of the plant results will be preserved, making this design a promising solution to overcome most of the limitations of the present technologies when low energy is available and large discharge variation occurs.