Center for the Built Environment

To achieve the radical improvements in building energy efficiency being called for by the State of California, it will be necessary to apply an integrated approach involving new designs, new technologies, new ways of operating buildings, new tools for design, commissioning and monitoring, and new understanding of what comprises a comfortable and productive indoor environment. This project, which is an amendment to CEC Contract 500-08-044, has focused on two space conditioning technologies that were part of the original project and showed significant potential to dramatically improve traditional levels of energy efficiency while also increasing occupant satisfaction and thermal comfort. The amendment allowed us to extend our ongoing research on these two promising technologies: personal comfort systems , and radiant heating and cooling systems.

The work done under this project has advanced the understanding of personal comfort systems and radiant heating and cooling systems, and has generated the following findings and recommendations: (1) four field demonstration studies with personal comfort systems technologies showed evidence of reduced zone heating energy use (as much as 46-75 percent for one study) while also dramatically improving occupant comfort under a variety of challenging thermal situations; (2) the personal comfort systems components tested in the four demonstration field studies included foot warming devices, leg warming devices, chairs that provide both heating and cooling, and small desk fans for cooling; (3) the results of the personal comfort systems field studies demonstrated that personal comfort systems have reached a level of performance that supports commercial market introduction; (4) building energy performance data, occupant satisfaction assessments, and valuable lessons learned from two successful and well-performing radiant slab office buildings; (5) development of an online map of buildings using radiant technologies to provide resources to building stakeholders who are interested in their implementation; (6) laboratory experiments comparing zone-level sensible cooling loads between radiant chilled ceiling and overhead air distribution systems confirmed the fundamental differences and implications for cooling load calculation methods; (7) two energy simulation studies showed that the David Brower Center design and heating, ventilating and air conditioning strategy present a viable design option in terms of predicted energy use and thermal comfort over a range of California climates, and demonstrated the potential impact of more accurately specifying furniture and contents (i.e., internal mass) on predicted zone peak cooling loads.