Project Title:

Methods for Mixed-Mode Building Field Studies

Proposing new protocols for assessing comfort in buildings with mixed-mode ventilation and personal comfort systems.

Status (updated 08/01/2013): Continuing

Funding sources: CBE Industry Consortium


Project Objective

Field studies that assess comfort in mixed-mode buildings and buildings with personal comfort systems are needed to evaluate which comfort model is the most appropriate. This project lays out a proposal for new standardized methods for conducting such studies.

Significance to Industry

Currently the adaptive comfort standard only applies to naturally ventilated buildings, and mixed-mode buildings have to comply with the more restrictive PMV-based standard. However, mixed-mode buildings fall along a wide continuum, of design and operating strategies. If we could study and define what types of such buildings an adaptive standard is in fact appropriate for, these expanded limits of applicability would give designers and operators much greater flexibility.

Research Approach

To formulate the new protocols for assessing thermal comfort, we interviewed professionals about what kind of data would be required for their work and also reviewed methods that have been used in the last twenty years. Based on this information, we first developed a “methods matrix” that categorizes methods based on the time frame of collection (background vs. real time) as well as the focus (building-based measurement or observation vs. occupant-based survey). We then identified six major categories of information that need to be collected and mapped them onto the methods matrix to formulate the protocol. The final proposal incorporates a building characteristics form, a general background survey, environmental measurements, and a “right-now” survey.

The new background survey was used at the National Renewable Energy Lab’s Research Support Facility. This test run has allowed us to identify improvements in the survey including clarifying the questions about workplace dress code flexibility and adding questions about why occupants do not operate windows.

Publications and Reports

Ackerly, K., G. Brager, and E. Arens, 2012. Data Collection Methods for Assessing Adaptive Comfort in Mixed-Mode Buildings and Personal Comfort Systems, CBE Summary Report, October.

Brager, G. and M. Pigman, 2013. Adaptive Comfort in Mixed-Mode Buildings: Research Support Facility, National Renewable Energy Lab. CBE Internal Report, April.

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CBE survey results

CBE survey results

Methods matrix