Phasing out fossil fuels in buildings is critical to achieving climate goals. New construction allows designers far more flexibility to optimize the design to achieve these goals, however in electrification retrofits the stakeholders must navigate the building’s existing conditions and associated constraints. To understand how the industry is tackling this challenge, we conducted a literature review of case studies, interviewed designers, and did extensive outreach to document electrification retrofits across the U.S. and Canada, yielding 142 projects across 39 states and territories. The dataset captures a wide range of project types, climates, and building typologies. Compared to a 2022 version of this map that included 45 projects, we found that demand for electrification is growing, albeit slowly, primarily due to public and private mandates, along with government and utility incentives. We identified common drivers and barriers to electrification and shared insight from projects that were explored but not pursued. Upfront and operating costs remain major obstacles in many locations, alongside space, structural, mechanical and electrical constraints. Successful projects are often completed in response to corporate or government mandates, have an internal champion, and rely on outside incentives. We compiled the dataset into an open-access map, offering examples of electrification retrofits.
Presented at the CEC EPRI Electrification Summit on June 10, 2026, this poster describes an ongoing California Energy Commission-funded research initiative (Grant Award #EPC-23-032) led by the California Institute for Energy and Environment (CIEE) and the Center for the Built Environment (CBE) at the University of California, Berkeley, which aims to provide a cost-effective pathway to substantially reduce carbon emissions from large commercial buildings through heat pumps and thermal storage, with key project components including the demonstration of a large, new heat recovery chiller using an ultra-low GWP refrigerant (R-1234ze, GWP=1, zero ozone depletion) at the Kaiser Permanente South San Francisco Medical Center — where the system is designed to provide chilled water while simultaneously rejecting heat at 140–170°F for building heating at a combined COP as high as 6.7 and cover greater than 50% of the annual heating load — alongside data-driven analysis of operating data collected from 37 buildings with all-electric heating and cooling plants, advanced model-based simulations of heating and cooling plant configurations and control strategies using Modelica, and multi-faceted market transformation activities including stakeholder interviews, a simplified web-based design tool, a list of electrical equipment, a guide on refrigerants, case studies, a commercial building electrification map, a large commercial building decarbonization design guide, and a policy recommendations memo.
The integration of ceiling fans with radiant systems remains underexplored despite their potential to address cooling capacity limitations. This study adopts a two-step approach to quantify the impact of elevated air movement on thermally activated building systems (TABS). First, we used OpenFOAM to calculate convective heat transfer coefficients under varying airflows, air-to-surface temperature differences, and zone sizes. These coefficients also apply to ceiling fans in buildings without radiant systems. Second, we implemented these coefficients in EnergyPlus to evaluate key radiant design parameters. Scenario 1 results show median steady-state cooling heat transfer rates increase of up to 47% relative to the no-fan cases when operative temperature is held constant. Scenario 2 demonstrates a median cooling effect of up to 4.8 K under fixed capacity, reflecting both lower zone temperatures and direct air movement on occupants. Overall, TABS-fans systems offer a scalable strategy to enhance comfort, increase capacity, and reduce energy demand.
High thermal mass radiant systems have strong potential for energy flexibility, but key parameter relationships remain unclear. This study conducts a comprehensive parameter sensitivity analysis of Thermally Activated Building Systems (TABS) and Embedded Surface Systems (ESS) using hundreds of thousands of simulations. Two representative cases, Hangzhou, China (humid subtropical) and San Francisco, USA (marine), are analyzed in depth, followed by cross-climate testing in eight additional cities spanning hot to mild climates. Results show that start/stop is the primary driver of load shifting potential, while start time has little effect on cooling energy supply. For Floor ESS, however, operation duration is critical: extending operation from 8 to 24 hours increases daily cooling supply by 25.9% in Hangzhou and 35.4% in San Francisco, compared to only 5-9% in other terminal types. Using San Francisco as an example, a comparison of fixed nighttime pre-cooling and flexible scheduling reveals key design levers, such as window-to-wall ratios and optimal orientations, that strengthen energy flexibility. Overall, the findings support a two-stage optimization: first, tuning operation timing and durations to maximize load shifting without excess cooling, and second, refining design parameters to enhance flexibility. These insights provide guidance for designing grid-interactive radiant cooling systems.
Heat recovery chillers (HRCs) are systems that utilize waste heat from the condenser side for heating purposes. As an electrification strategy, they offer the potential to reduce operational carbon emissions associated with heating, while providing higher coefficient of performance (COP) than air-to-water heat pumps and a much smaller equipment footprint. However, limited research has been published on the real-world performance of HRCs in this configuration. This study investigates the performance of HRCs in a newly constructed all-electric building located in ASHRAE climate zone 3C. The building is a five-story, 182,800 ft2 (17,000 m2) outpatient surgery and medical office facility. In this facility, HRCs serve as the primary plant equipment to meet the building’s heating and cooling loads, with exhaust air coils functioning as either a heat sink or source to balance loads on the HRCs. The building entirely relies on the HRCs and exhaust air coils for all cooling capacity and has no storage (aside from buffer tanks). We analyze high-resolution measured data from the building’s central plant, including water-side loads and electrical power, across multiple seasons, focusing on how plant performance varies with outdoor air temperature, building heating and cooling load profiles, and the balance between heating and cooling loads. When thermal storage is limited, the balance between heating and cooling load becomes a more critical factor in determining system performance. When there is a mismatch between the two loads, the system either rejects or sources heat to or from the exhaust air to balance the loads on the HRCs. This balance is driven by both outdoor air conditions and building loads. Unlike true simultaneous heating and cooling loads, the exhaust air loads are not used for a purpose within the building and effectively reduce overall system efficiency. This study captures the complexity and variability of actual system performance and proposes a new metric for assessing performance in these systems. The building demonstrates the technical feasibility and high performance of using HRCs with exhaust air coils in all-electric medical buildings.
Multi-zone variable air volume (MZ VAV) heating, ventilation, and air conditioning (HVAC) systems are commonly used in commercial buildings, but their performance varies widely, leading to a significant performance gap between best practice and typical operation. The supply air temperature (SAT) reset strategy significantly influences the energy efficiency of VAV systems. This paper presents the field implementation and validation of a novel SAT control method, Cost-Optimized Reset (CORE) in three commercial buildings in California. To evaluate the real-world performance of CORE, we conducted a measurement and verification (M&V) analysis using a randomized crossover trial approach over the course of the monitoring period. Energy consumption, HVAC operational parameters, and utility rates were analyzed and showed 5-22% energy savings in combined heating, cooling and fan energy, and 1-20% savings in related energy cost for CORE compared to the existing SAT reset strategy with no reported compromise to occupant comfort or system stability. The work also highlights implementation challenges and solutions and provides practical insights for scaling advanced control strategies across broader building portfolios. Through this field validation, CORE demonstrates its potential to serve as a cost-effective and scalable control strategy that aligns with the goals of improving energy efficiency and reducing carbon emissions in commercial buildings.
This quick guide is intended to provide a simple summary of changing refrigerant requirements for HVAC applications based on Federal and California regulations. Though there are broader implications for other industries (including industrial and transportation), this guide focuses on commercial HVAC applications.
The supply air temperature (SAT) setpoint control strategy is a vital part of a variable air volume (VAV) system. This paper presents a new cost-responsive (CORE) SAT control algorithm for the VAV system which does not require discharge air temperature data for easier implementation, along with a new humidity control strategy that constrains the maximum SAT based on outdoor dewpoint temperature to meet dehumidification requirements in humid climates. We conducted a comprehensive parametric simulation study using a representative office building model to assess energy cost savings of the new CORE control algorithm against other widely adopted control strategies, including the best industry practice ASHRAE Guideline 36 (G36). We created an EnergyPlus-Python-based simulation environment to implement all control algorithms. Results showed that the new CORE algorithm consistently yielded higher energy cost savings than others, despite variations in climate, energy tariff structure, and building design and operation. Compared to G36, the new CORE algorithm reduced energy costs by a mean (first – third quartiles) of ∼ 4 % (0.8–6.9 %) across all simulated cases. Moreover, the climatic conditions had a significant impact on the control performance. In milder climates, the new CORE algorithm achieved higher energy cost savings due to considerable economizer hours, e.g., with ∼ 7 % (6.3–7.1 %) savings compared to G36 and ∼ 31 % (26.8–36.0 %) compared to the worst-performing fixed SAT strategy for Oakland. Conversely, in more extreme climates with fewer economizer hours and dehumidification constraints, energy cost savings of the new CORE algorithm were diminished, e.g., with 0.6 % (0.2–0.7 %) savings relative to G36 and 5.4 % (4.3–6.2 %) relative to the least effective Warmest SAT strategy for New York City. These findings demonstrate the potential of the new CORE SAT control strategy to reduce HVAC operating costs while maintaining occupant comfort.
The need for cooling in buildings is mainly handled using systems based on the refrigeration cycle, often an energy- and cost-intensive process. High thermal mass radiant systems (HTMR) enable the use of warmer than typical chilled water temperatures to provide cooling. In favorable weather conditions, the cooled water can be produced through low-energy and low-cost cooling devices. In this two-phased study, we first determined the warmest supply water temperature (SWT) needed in HTMR that maintains thermally comfortable conditions on the cooling design day. Then, we investigated the potential of replacing the refrigeration cycle with evaporative cooling devices in the primary cooling system. We performed a quasi-random sampling of building and HTMR system design parameters representing typical building characteristics and design cooling loads for lighting, people, and plug loads to create 360,900 single zone EnergyPlus models. We iteratively simulated the models on the climate zones’ cooling design day to find the warmest SWT that did not exceed a maximum zone operative temperature of 26 °C. The test cases include simulations using 14 ASHRAE and 16 California climate zones. The results show that HTMR can use SWT of 12.3, 18.2, and 21.1 °C for the 25th, 50th, and 75th percentile, respectively, of test cases, indicating that overall cooling energy and costs can be reduced in all US climates through high-temperature cooling. In addition, high-temperature cooling allows at least 40% of waterside economizer operation during the cooling season for 21 out of 30 climate zones with reasonably performing evaporative cooling devices.
High thermal mass radiant systems as a hydronic thermal mass activation method have many opportunities for cost-effective demand management. The system is regarded with the possibility of long-term transferring peak heating and cooling loads to off-peak hours and peak load reductions. This study conducted over 300,000 case calculations for a sensitivity analysis of load shifting parameters in radiant space conditioning systems across 16 climate zones in California, 14 different climatic cities outside California. The parameters analyzed include building geometric parameters (building length, width, window-to-wall ratio, orientation), internal heat source levels (from people, lights, plugs), control parameters (start and stop times), and the design construction of radiant terminals. A comparative analysis was also conducted across cities in different climatic conditions to explore the impact of climate on the load shifting capabilities of radiant space conditioning. The results of this study will aid in the formulation of strategies and the optimization design for load shifting in radiant cooling systems.
