Comprehensive Energy Efficiency Treatment
OpTerra performed an in-depth comprehensive energy analysis for United Electric Controls in Watertown, Massachusetts.
The existing manufacturing space HVAC consisted of four constant volume (CV) Air Handling Units (AHUs) served by one 240-ton air cooled chiller. The AHUs operated continuously, as there was no control over the space other than mercury thermostats. OpTerra retrofitted the existing chiller compressors in the manufacturing area with three 80-ton VFD Magnetic Bearing Compressors, converting the system from CV to Variable Air Volume (VAV). OpTerra also replaced the existing two 20 Hp air-cooled air compressors in the mechanical room with one Hp high efficiency VFD air compressor.
Heat rejected from the existing compressors was going directly into the return air of the mechanical room’s AHUs. The compressor was therefore installed in an unconditioned space next to the loading dock in order to reduce the impact on the building’s cooling load. A new Energy Management System (EMS) was installed to provide scheduling, setback and optimum start/stop control strategies.
HVAC energy conservation measures designed and implemented by OpTerra will save United Electric Controls over $130,000 annually.
OpTerra retrofitted the existing lighting system, consisting primarily of eight foot T-8 industrial fixtures with more efficient super T-8 lamps and ballasts. The existing lighting system was controlled by simple switches. OpTerra installed wall and ceiling mounted occupancy sensors in office spaces in order to switch off lighting when the space was unoccupied.
OpTerra’s installation of a more efficient lighting design will save United Electric Controls over $40,000 annually.