Modern buildings are collections of multiple systems—heating, ventilating, cooling, water, electrical, controls, security, fire—all interacting with one another in and around the building environs. For a variety of reasons, quite commonly not everything will work as intended by the manufacturer or the building owner after installation.
Commissioning is meant to address this problem. A commissioning agent works with the vendors and the building owner during construction of a new building or a major renovation to ensure that systems operate as designed, interact properly and perform according to the owner’s requirements. Retro-commissioning is a similar process applied to buildings that have never been commissioned. The Alliance engaged TestMarcx Commissioning Solutions (TMCx) in late 2010 to carry out a retro-commissioning investigation and preliminary energy analysis to help identify opportunities for saving energy and improving occupant comfort at the Alliance Center.
The TMCx team found a number of things amiss, including dysfunctional HVAC system parts, an inoperative exhaust fan, a leaky water heater, and thermostats mounted on window frames rather than interior walls (which, because of heat conductance through the walls, caused the thermostats to misread interior temperatures). TMCx also conducted a tenant survey, which exposed other problems. Respondents complained of areas that were too cold or too warm. Several found the building noisy on occasion, mainly because of sound transmission through walls and floors. Over half complained of unpleasant odors, probably attributable to the inoperative exhaust fan. There was a variety of mixed complaints about light levels in specific areas.
Based on their assessment, TMCx recommended a number of measures to address these issues, including some no- or low-cost measures as well as others requiring more substantial investments. The most significant items were relocating the thermostats, repairing defective diffuser units, and replacing the entire DX rooftop cooling unit and the electric radiant heat panels with a new cooling unit and gas-fired heat. The need for DX unit replacement was well known as the unit was nearing the end of its useful life. TMCx put the cost at roughly $200,000 and the simple payback time at 20 years.
