SYSTEM FLUID FILTRATION

If corrosion is present in the geothermal loop fluid stream, in the form of suspended solids, it should be removed immediately. Ignoring this type of particulate matter has the potential to produce long term catastrophic results in any type of heating or cooling system, including geothermal heat pumps.

The simplest way to remove any type of particulate matter from a geothermal loop system is to flush and filter the fluid until it is clean and clear of any foreign material. This can be accomplished in one of two ways. The first option involves shutting down the entire system to completely flush and filter both the exterior geothermal loop field as well as the interior mechanical pipe loop inside the building. This option is typically used in an emergency situation if a system is experiencing problems or it is completed during a regularly scheduled maintenance shut down for a facility. Since this option can be both costly and impractical in certain situations, an alternative approach is to install a permanent “side stream” filter that has the ability to continuously filter the entire system.

This approach provides additional benefits for monitoring the system. A side stream filter can be inspected at regular intervals to evaluate filter conditions and to change disposable filters as needed. In addition, water samples can be obtained for water quality testing at recommended intervals without interrupting normal system operations. Side stream filters provide a valuable, cost effective asset to any system owner who is concerned with maintaining the long term efficiency of a geothermal heat pump system, and should be seriously considered when evaluating a comprehensive, long term facility or maintenance plan.

Manifold/Vault Inspections

Large scale commercial geothermal loop systems contain manifold piping that can be installed inside a building in a mechanical room, or outside a building in an underground manifold vault. In either instance, manifold piping and it related component parts should be inspected at regular intervals.

In many cases, “out of sight is out of mind” when it comes to inspecting underground manifold vaults. These structures can be easily overlooked when considering the maintenance requirements for a geothermal loop system. Failing to conduct regular inspections can be a costly mistake.

At a minimum, a semi-annual visual inspection should be made of all manifold pipes, isolation valves, circuit balancing valves, manual or automatic air vents, pressure/temperature ports, thermometers, pressure gauges, check valves and sump pumps contained in underground manifold or distribution vaults.

In addition to visual inspections of manifold systems, flow testing is recommended to verify that the loop system is operating within original design parameters that were determined for optimizing both heating and cooling efficiency. Non-invasive testing, utilizing an ultrasonic flow meter can be conducted to evaluate the system flow rate as well as individual flow rates of each piping circuit that is connected to a manifold and should be included in any long term maintenance program.