Building Automation System Case Studies

Benefit of O&M Controls Assessments

A 250,000 square foot office building in downtown Nashville, Tennessee, was renovated in 1993. The renovation included installing: 1) a direct digital control (DDC) energy management control system to control the variable air volume (VAV) HVAC system and lighting, and 2) a variable frequency drive (VFD) for the chilled water system. The building was not commissioned as part of the renovation. An O&M assessment was performed 3 years later because the building was experiencing problems and energy bills seemed higher then expected. As a result of the assessment, a total of 32 O&M-related problems, including a major indoor air quality (IAQ) deficiency, were identified. It was also determined that the majority of these problems had been present since the renovation. Annual energy savings from the recommended O&M improvements and repairs are estimated at $9,300. The simple payback for both the assessment and implementation is under 7 months.