In this paper we present the results from field studies of two low-energy office buildings in California, both using radiant slab ceiling systems (thermally activated building systems, TABS) for primary cooling and heating in the buildings. Both buildings are certified LEED Platinum and incorporate a wide range of energy efficient technologies and design strategies, including TABS, advanced shading systems, underfloor air distribution, chilled beams, ceiling fans, natural ventilation, and photovoltaic panels. Findings and analysis from the following building performance assessment techniques will be discussed.
- Occupant satisfaction survey. Occupant surveys are an invaluable source of information for describing how well the building is providing a high quality indoor environment for the occupants. In addition, the survey results are also compared against a large benchmark survey database of over 50,000 occupants.
- Wireless measurement system. A network of wireless sensors was installed in selected zones of the buildings to provide additional more detailed information about the operation and control of the radiant slab system. This data was combined with trend data from the building management system (BMS) to examine the performance of the buildings during both winter and summer conditions. Some control issues were identified and corrected based on these measurements.
- Energy performance analysis. We collected utility data for 2014 in one of the buildings and used this information to determine the building’s Energy Star rating.