Exhaust Air Mechanical Heat Recovery Field Data Evaluation and Measure Development

The project will evaluate the performance of heat recovery chillers (“HRCs”) paired with exhaust air coils in high-ventilation-rate commercial buildings, where the technology is especially well-suited to balance simultaneous heating and cooling loads. The evaluation will include an enhanced field data analysis at a site where this technology has already been installed to understand how the technology can be applied to utility programs, and an energy modeling study to determine how to include the technology in utility program impact estimates. The HRCs being analyzed in this field study are coupled with exhaust air coils to enable partial or full electrification via heat recovery. HRCs combined with exhaust air coils leverages waste heat from building exhaust to supply hydronic heating to reduce gas use and improve system efficiency. The project team will quantify benefits and support measure package development by leveraging existing data for modeling and field verification. The resulting analysis will provide insights to help utilities leverage HRC combined with exhaust air coils to advance high-efficiency, grid-responsive, and cost-effective decarbonization strategies. This solution offers a full or partial electrification pathway that will substantially reduce electricity consumption compared to other incumbent alternates (e.g., air-to-water heat pumps in new construction) or substantially reduce both emissions and total utility costs (for example, in retrofit applications after accounting for natural gas, electricity, and water consumption). The project will quantify system benefits and identify barriers to adoption, providing the evidence base needed to advance HRC systems through the custom incentive pathway with the California Technical Forum (“CalTF”), Investor-Owned Utilities (“IOUs”), and the California Public Utilities Commission (“CPUC”). 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 physical equipment footprint in the building. However, limited research has been published on the real-world performance of HRCs in this configuration. These systems are attractive in high-ventilation buildings such as hospitals, laboratories, and large commercial facilities, where exhaust heat availability is substantial and simultaneous heating and cooling loads are common.Many mechanical contractors are familiar with chilled-water systems as the burgeoning commercial HRC market is served by major original equipment manufacturers (“OEMs”). However, designers and installers often lack guidance on integrating HRCs with exhaust air coils for dual heat recovery and rejection. EnergyPlus modeling capabilities for this configuration are not well established, and a gap analysis of current modeling tools is needed to ensure that the system can be accurately represented in standard compliance and program evaluation frameworks. This project will engage manufacturers, mechanical engineers, and program administrators to close these gaps through validated models and measure inputs.Custom and site-specific measures are particularly well suited for large-building HRC applications, where higher energy consumption translates to greater incentive and savings potential. CalTF is actively working to streamline and modernize the custom incentive pathway, which has historically been challenging for both program administrators and project teams. Understanding where this technology fits within that evolving landscape, and what evidence the CPUC and IOUs need as support, is central to this project.This project ties closely to work conducted under a parallel project titled 'Hydronic Heat Recovery Measure Development.' This project is focused on buildings with high ventilation rates (e.g. required minimum outdoor air flow rates substantially above 1 air change per hour, such as laboratories, hospitals, and other healthcare facilities) whereas that project is focused on other use cases.