NASA Langley Research Center had ten buildings with critical central HVAC systems at the end of their useful lives. Updates were needed to address the potential for equipment failure and create opportunities to improve overall energy efficiency. B&N was retained by NASA to design the replacement of the HVAC systems at all 10 buildings. This included evaluating three solutions for each building over a 20-year life cycle to determine the option with the lowest net present value, followed by developing construction documents for public bid. In addition, the project team:
- Converted outdated multizone units to modern VAV systems
- Converted absorption chiller plants to water-cooled chiller plants
- Replaced steam coils with hot water coils via smart heat exchangers
- Optimized DDC control systems for improved building system efficiency
- Upgraded the main electrical service infrastructure
- Made structural roof framing modifications
- Provided supplemental architecture and HAZMAT abatement
Energy Efficient Solutions
To help NASA improve the energy efficiency of these buildings, steam heating was removed. Two absorption chiller plants that used steam to provide cooling to the building were replaced with electrically powered water-cooled chiller plants which significantly improves plant efficiency. With this update, specialty contractors are no longer needed for maintenance which can now be subcontracted to a wider pool of vendors or conducted by NASA staff.
Outdated multizone central station air handling units were replaced with modern variable air volume central station air handlers and new terminal units. This improved energy efficiency and thermal comfort due to improved zone control and indoor air quality due to the addition of MERV 8 pre-filters and MERV 13 final filters.
In addition, the team replaced a dedicated outside air system at one of the buildings with a system that returns air exhaust through the unit, transferring sensible and latent heat back into the system. This was designed within tight constraints to allow the new unit to fit within the available footprint.