Building Energy Analysis Group

Here's a brief description of some Building Energy Measurement and Performance Analysis research that we did during 1996-1997. A more refined (but probably shortened) version will appear in the EETD Annual Report. The researchers responsible for the work are listed at the end of each description.

Projects in Building Energy Measurement and Performance Analysis

Building Energy Measurement and Performance Analysis undertakes diverse research on the performance of buildings through both direct measurement and simulation. Staff examine the energy use of buildings, from single-family, low-energy homes, to large, office buildings, and even the microclimates around them. Other projects focus on the equipment inside buildings, from domestic refrigerators to large commercial chillers. Building Energy Measurement and Performance Analysis staff also consider the interactions between occupants and equipment, since a dissatisfied occupant can easily frustrate the cleverest technology.

The group's largest project is investigating ways to mitigate urban heat islands in order to reduce peak demand for electricity and smog in urban areas. One research goal is materials that have higher reflectivities, or albedos, but that do not appear "white" or shiny. The research is focusing on roofs and road surfaces. This year Building Energy Measurement and Performance Analysis staff developed a test procedure that will allow different roofing materials to be rated according to their albedo. In the future, roofing materials will have labels, which will permit consumers to select a roof that will reduce their air conditioning energy use. Smog-prone areas, such as Los Angeles, may also establish minimum albedos for roofs as part of their strategy to reduce smog. Further modeling by Building Energy Measurement and Performance Analysis staff has estimated the reductions in smog caused by wide-scale increases in the surface albedo. (Hashem Akbari, Haider Taha, Lisa Gartland)

Long-term performance of buildings has become an increasingly important issue. Commercial buildings are constantly being retrofitted, remodeled, and put to different uses. As a result, it is difficult to distinguish between deterioration in energy performance and changes in occupancy or usage. Building Energy Measurement and Performance Analysis staff are developing data collection, visualization, and analysis procedures to help building operators detect performance degradation and failing equipment. In one case, they found a building's chiller was oversized by 50% but the building operator did not realize it because construction debris had damaged the chiller. In this area, the energy-saving benefits from long-term performance monitoring are often dwarfed by savings from avoided maintenance costs and down-time. (Mary Ann Piette)

In a continuing effort to understand and help improve the energy use in office equipment, Building Energy Measurement and Performance Analysis staff found that a major fraction of the energy-saving features of personal computers were disabled. Building Energy Measurement and Performance Analysis staff wrote a "User's Guide" for power management of personal computers and monitors based on these observations. This guide helps people understand how power management works and can reduce electricity use through properly enabling their PCs. (Bruce Nordman)

If the occupants are not satisfied with the environment inside a building, then productivity suffers and health complaints rise. Building Energy Measurement and Performance Analysis staff are evaluating office workers' responses to an integrated wall system that includes automated venetian blinds and lighting. This system optimizes admission of daylight and solar heat gain, but do people like it? These kinds of surveys are essential to ensure that energy-efficient technologies actually result in saved energy. Other evaluations underway include the EPA's Energy Star program for new homes and compliance with building codes. (Ed Vine)

An increasing fraction - about 20% - of the electricity used in homes does not fall into any simple category and is often called "miscellaneous." Building Energy Measurement and Performance Analysis staff have been investigating the miscellaneous end use because it appears to be the fastest growing segment of residential consumption. Recently, they focused on the "leaking" fraction, that is the electricity consumed by appliances when they are switched off or not providing useful services. Measurements in homes in the United States and Japan suggest that homes typically "leak" 50 Watts, an amount roughly equal to the energy consumed by a modern refrigerator. A variety of technical fixes exist, ranging from simply re-positioning the off-switch to designing special chips to manage power and storage. (Alan Meier)

Building energy simulation models are useful tools to explore energy savings opportunities of new technologies. Building Energy Measurement and Performance Analysis staff have investigated the potential for "compressor-free cooling" that relies on a combination of night-time cooling, ventilation and possibly an evaporative cooler. A carefully-designed house in almost any California urban location should be able to maintain comfortable conditions without a compressor-based air conditioning system. Simulation permits exploration of the extent and duration of periods where thermal discomfort might occur. Even if houses continue to use a compressor-based air conditioner, this research shows the extent to which the unit can be down-sized through improvements to the building envelope and ventilation system. (Joe Huang)

Staff web pages and e-mail addresses

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