This spring CBE’s team is at the forefront of the conversation on building performance, decarbonization, and professional leadership. We are co-hosting a symposium on circularity, presenting in key conferences, and announcing news on new research, energy code revisions, and numerous latest publications.
Circularity in Practice: Case Studies and Strategies for Circular Design and Construction, April 22, 12:30 – 7:00 PM | San Francisco
Circular design considers the entire lifecycle of buildings, embracing strategies of reuse, adaptation and renewal, and providing a framework for addressing climate change, material waste, and biodiversity loss. CBE is pleased to serve as a community partner for this symposium, hosted by AIA San Francisco on April 22nd (Earth Day). The event includes keynotes from Kjell Anderson of LMN Architects and Kathleen Hetrick of BuroHappold, plus expert panelists who will discuss large- and smaller-scale projects, product lightning sessions and perspectives from the field. With our partnership with AIASF, CBE will cover a portion of ticket fees for current CBE industry partners. See the agenda >
CBE Director Gail Brager to Open the Women in ASHRAE Leadership Symposium, April 13-14 | Los Angeles
In her opening keynote, Prof. Gail Brager will share perspectives and insights gleaned from her decades of teaching and leading research, and emphasize that addressing today’s environmental challenges requires more than technical excellence. It calls for breaking down silos, bridging research and practice, aligning design with operations, and starting critical conversations early. Women in engineering are uniquely positioned for this — they are often the connectors — linking perspectives, fostering collaboration, and ensuring that human impact is never secondary to technical goals. Learn more >
California Green Building Conference, May 27-28 | University of California, Berkeley
We are excited that USGBC California’s annual conference will take place here at the UC Berkeley campus this spring. The lineup includes panel sessions, roundtables, networking events and gatherings to bring together leaders and emerging professionals from across the green building community. CBE’s Gail Brager, Matt Roberts, Paul Raftery and David Lehrer will lead a panel showcasing key impacts and outcomes that are coming from industry/university research collaborations. Check out the conference website >
Research News and Publications
Below we feature recent publications by CBE researchers, faculty, graduate students and research affiliates, plus new funding awards.
New Study Will Advance Building and Grid Decarbonization Through Ultra-Low GWP Heat Pumps
With new funding from the California Energy Commission, CBE will develop and test an ultra-low global warming potential (GWP) heat pump integrated with thermal energy storage. This system will provide space heating and cooling, plus domestic hot water, while efficiently enabling demand flexibility in residential buildings at lower cost than leading alternatives. The air-to-water heat pump to be studied uses R-290, a refrigerant with an ultra-low GWP that is widely used in Europe and Asia, but not approved in the U.S. (It is commonly known as propane.) The work is supported with in-kind support from Midea, Harvest Thermal and PG&E.
CBE Research Contributes to Energy-Saving Revision to California Energy Standards
Past CBE research revealed significant inefficiency from hot-water reheat systems in variable-air-volume systems in commercial buildings. In fact, studies showed that only 17% of heating energy cost was useful reheat, the rest was wasted due to boiler inefficiency at ultra-low part loads, distribution losses and pumping power. Two studies, described here and here, have been cited in the advancement of a new measure in California’s Title-24 energy code, mandating a limit of 130°F on hot water supply temperatures for space heating design in new construction, additions, or alterations. For details, see the Codes and Standards Enhancement (CASE) report.
New publication: Temporal Resolution Matters: Evaluating Carbon Emission Factors for Accurate Accounting in Commercial Buildings
Accurately quantifying operational carbon emissions from buildings is essential to verify that decarbonization targets are met. Yet many current practices rely on simplified yearly averages that overlook the temporal variability of the electrical grid generation. Our recent paper demonstrates that annual average factors should not be used for assessing operational or avoided carbon emissions. The authors suggest that season-hour and month-hour average emission factors deliver sufficient accuracy with median errors typically below 10%.
New publication: Demonstrating the Reliability of Randomized Measurement and Verification for Switchable Control Retrofits Using a Large Open-Source Dataset
Conventional measurement and verification (M&V) methods for estimating energy savings rely on comparing pre- and post-retrofit performance. In a recently published study, CBE researchers demonstrate that switchable interventions, for example with HVAC control retrofits, can benefit from a new M&V method that randomly implements the baseline or the intervention at a fixed interval, for example daily. Compared to conventional methods, the randomized M&V method provides more accurate savings estimations, with a median of 74% accuracy improvement. It may also reduce the required study duration by as much as 65%.