Performance of a low-energy commercial building designed using a whole-building approach

The Thermal Test Facility (TTF) at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, demonstrates that using a whole-building design approach successfully produces an extremely low-energy building. A whole-building approach treats a building as a single unit not a shell containing many separate systems. By using this approach for the TTF, the team of NREL researchers and designers produced a building that costs 63% less to operate than a code-compliant basecase building. These savings were achieved by implementing an approach that optimized passive solar technologies and integrated energy-efficient building systems. Passive solar technologies included daylighting, high-efficiency lighting systems, engineered overhangs, direct solar gains for heating, thermal mass building materials, managed glazing, and a good thermal envelope. The energy-efficient HVAC system, designed to work with the building's passive solar technologies, includes ventilation air preheat, ceiling fans, indirect/direct evaporative cooling, and an automatic control system. This paper presents results of tests conducted since the building's completion in 1996 that demonstrate the success of the TTF's design. Modeling building energy performance, calibrating those models, and monitoring building performance will be discussed.