The North Table Mountain Water Treatment Plant expansion includes a brand-new ground-up Administrative Building and capacity expansion for the water filter treatment facility. The new Administrative Building has a unique energy savings sequence for the heating and cooling HVAC system. Each tempered zone is serviced by a zone-specific water source heat pump and individually controlled with thermostats for comfort adjustment. The treatment facility has access to large quantities of treated wastewater that functions as a natural source for energy storage. The water source heat pump condenser loop either siphons from or rejects heat to the wastewater energy well through a heat exchanger, conditional on the season and temperature differential of the source water. This process provides preliminary heating and cooling from an otherwise unutilized source, thus reducing the system’s dependence on mechanically provided cooling and heating. While there are hydronic boilers for supplemental heating in winter conditions, the ability to reject heat into the wastewater energy well eliminates the need for traditional heat rejection equipment, such as a cooling tower, and the associated energy used by such equipment.
In addition to the mechanical and plumbing engineering design, 360 Engineering also performed the commissioning for the project. While any project can benefit from commissioning, it becomes even more critical for high-performance mechanical systems like this. Although the system appeared to be working at the start of commissioning, the process revealed some controls programming issues in operating conditions that may not have been seen for months. By simulating all the possible scenarios of operations, the issues could be identified and resolved before they affected the building functionality and before the contractors demobilized, rather than a drawn-out warranty call in the middle of summer with a hot building.
