Fouling and clogging surveillance in open loop GSHP systems

Abstract

Fouling and clogging are some of the major water quality problems encountered in open loop ground source heat pump (GSHP) systems and aquifer thermal energy storage (ATES) systems. Here we present a surveillance strategy that can detect if and identify where in the system fouling and clogging might be developing without having to shut off the heat pump. In the presented system design, the test requires a minimum of four temperature sensors and two pressure sensors to describe the performance of the four major heat source system components, namely, the production well, the injection well, the submersible pump and the groundwater heat exchanger. The surveillance procedure involves conducting a step-test with incremental increases in the groundwater flow rate while measuring the pressure and temperature responses in the system components. The performance of the newly constructed installation functions as a baseline for future tests. By conducting the test systematically during operation an altered performance of the system can indicate clogging or fouling issues. Even though the cause of the problem must be identified through other means, the surveillance procedure presented here allows the operator to plan necessary maintenance and avoid critical damage to the heat source system.