Published July 1, 2023
Effective September 1, 2023
High-efficiency all-electric HVAC systems continue to be a priority for CalNEXT. This includes maturing products such as high-efficiency air-to-air packaged heat pumps as well as less mature product markets, like air-to-water heat pumps intended for gas boiler replacements. CalNEXT is also focused on deploying scalable HVAC solutions and decarbonization design strategies to create high-impact opportunities for the commercial and multi-family sectors.
High-efficiency compressor-based packaged equipment that can provide efficient electric heating (and often cooling). Systems may include high efficiency air-to-air packaged HP units (ducted unitary HPs and ducted or ductless split systems), air-to-water HPs used to replace traditional boiler hydronic systems, or Variable Refrigerant Flow (VRF). “High-efficiency” equipment typically contains variable speed (VS) fans, compressors, and/or pumps. Other pathways to high efficiency include advanced heat exchangers and advanced controls algorithms.
Variable Speed heat pumps: Air-to-water HPs, air-to-air HPs, Variable Refrigerant Flow, and split-system packaged HPs.
High-efficiency HPs present significant energy efficiency (EE) and decarbonization potential relative to fixed-speed equipment with traditional gas-fired heating. Variable speed compressors also enable more robust demand flexibility. Generally, any heat pump replacing a furnace or boiler will result in improved local air quality and potentially indoor-air quality through avoided gas combustion which may be a consideration for Disadvantaged Communities (DAC) and Hard-to-Reach (HTR) communities. Prospective research should focus on field validation of high efficiency HP performance, especially when in heating mode to validate product efficiency, heating capacity, product sizing, and the related heating-performance metrics.
Packaged HPs are a well-researched field with mature ratings systems and testing methods. Federal standards for residential central air and split system HPs were recently updated on January 1, 2023, which established new efficiency ratings (EER2/SEER2/HSPF2) and test procedures which include additional rating data at colder temperatures. However, new standards may continue to under-represent the benefits of variable speed equipment and other advanced features that are poorly captured under current metrics. This may be particularly important for the predominately mild heating needs of California and the common oversizing practices. This can lead to uncertainty in real-world benefits of these products when compared with single speed products. Continued research will be helpful to ensure right-sizing of products and may help programs fully account for the known benefits of high efficiency, variable speed products. As new products emerge to meet the broad decarbonization space-heating needs such as air-to-water HPs for boiler replacements or small-scale heat pumps designed for single rooms, there is a need for similar industry standardization of test procedures and ratings as well as field performance validation both of which are limiting the ability of utility programs to influence these new markets.
Advancement of sensors, controllers, and demonstrations of new control strategies and technologies that improve the persistent performance of a building’s HVAC energy use and component functionality with an emphasis on scalability and deployment of control systems. This technology family has strong overlaps with the Installation, Operations, and Maintenance technology family.
Building Automation Systems (BAS), Automated Fault Detection Diagnostics (FDD), Advanced monitoring, data analytics and benchmarking, grid-adaptive controls, load management controls, and smart thermostats (residential & small commercial).
Emerging technologies in Scalable HVAC Controls have strong opportunities to improve energy savings and demand flexibility performance in commercial buildings. The February 2020 DOE report “Innovations in Sensors and Controls for Building Energy Management,” estimated an aggregated annual energy savings of 29% is possible in the commercial sector alone through the implementation of EE measures using current state-of-the-art sensors and controls innovations. Studies showed 10-20% of commercial building peak load can be temporarily managed or curtailed to provide grid services but require better interoperability. Recent development to standardize advanced control strategies through efforts like American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Guideline 36 provide significant opportunity to scale quality control implementation at lower cost to building owners. Future research should focus on (1) demonstration of strategies to reduce system complexity, installation, and commissioning cost; (2) field validation to support value proposition; and (3) enhancement of technology to support autonomous and operator-centric operation; and (4) development of technology to improve system interoperability.
For residential and small commercial buildings with unitary HVAC systems, there is a rapid adoption of smart thermostats, either provided by third-party or integrated with the HVAC product, that support automated energy and load management and integration with connected devices. The Environmental Protection Agency (EPA) has led the way in bringing demand flexibility capabilities and system monitoring to unitary systems under the ENERGY STAR® Smart Thermostat Specification V1.0, suggesting CalNEXT focus on “smart” thermostat deployment and program enrollment. While new thermostats optimized for variable capacity HVAC systems remains an untapped opportunity, there is limited performance validation such that they will not be incorporated under the ongoing ENERGY STAR® Specification v2.0 update. New research should seek to validate the performance of variable-capacity smart thermostats to inform future product standards.
Technical understanding of advanced HVAC controls is a well-researched area, often studied in larger buildings. Due to the varied components, complexity, maintenance procedures, and climate needs in commercial buildings, the magnitude and persistence of savings can vary significantly. CA IOUs codes and standards programs have been actively researching commercial HVAC controls in support of building code enhancements and retro-commissioning programs have provided incentives for improving existing building HVAC controls. In the residential sector, deployment of smart thermostats should remain the focus with special attention to research in program designs that can improve consumer education to ensure the energy savings potential is realized across all communities.
HVAC cooling and heating systems that use alternatives to vapor compression cycles or hybrid combinations of alternatives along with vapor compression cycles. While evaporative cooling represents the most mature and developed of these, this family also includes desiccant systems, absorption, adsorption, thermoacoustic, thermoelectric, magnetocaloric, electrochemical, and others.
Evaporative and indirect evaporative cooling or other alternatives to vapor compression cycles such as desiccant-based, absorption, thermoacoustic, thermoelectric, electrochemical, and radiant heat rejection.
ET research in this technology family has the potential to yield strong EE savings potential, result in permanent load reductions, and reduce or eliminate refrigerant emissions related to traditional vapor-compression HVAC systems. While evaporative cooling is the most established technology subgroup, the water usage continues to be an important consideration for long-term drought conditions that warrants careful consideration to balance the energy savings benefits compared to increased water usage. Several non-evaporative technologies have seen minimal market uptake and appear to be several years away from broader adoption. Prospective research should focus on (1) lab and field demonstrations of non-evaporative, non-vapor compression alternative HVAC technologies with the ability to scale to mass production in the near term and (2) novel water efficiency strategies to reduce blowdown and drift from cooling towers.
Multiple studies have demonstrated significant energy savings for evaporative systems. Design complexities, high first costs, and non-trivial maintenance needs have been traditional barriers to deploying evaporative cooling, particularly at smaller scale. Future water scarcity may be an additional barrier. At the residential level, increasing frequency of heat waves may push consumers to adopt low first-cost evaporative coolers.
Recent ET research has resulted in the development of a measure package for evaporative pre-cooler systems for very large commercial package units. Meanwhile, non-evaporative, non-vapor compression systems are still in a very nascent stage of development, with limited commercially available products. Prospective research should focus on (1) understanding ideal use cases of evaporative systems, (2) lab and field studies testing of new evaporative equipment designs that reduce or overcome these barriers, (3) developing efficiency program strategies for overcoming market barriers, and (4) enhancement of existing design tools to include hybrid or fully compressor-less HVAC systems.
Innovative program designs and supporting research to accelerate deployment of the California HP market. May include financing innovations, turn-key incentive design, or other coordination with various market actors focused on HP deployment. This technology family will help meet the California Energy Commission’s (CEC’s) goal of installing at least 6 million HPs by 2030. This technology family was previously referred to as “Heat Pump Market Transformation”.
Program designs, deployment strategies, financing mechanisms, and other research to assist in market deployment of the HVAC sector.
HP deployment is a key pathway for decarbonizing California’s building stock and to maximize their impact, they will need to be energy efficient with demand flexible capabilities. Within colder regions of California, there is need to investigate opportunities to deploy cold climate heat pumps in place of furnaces or dual-fuel heat pumps. The 2021 Inflation Reduction Act (IRA) will accelerate the existing HP market deployment activities over the next decade. The law establishes tax credits for high efficiency HPs and provides point-of-sale incentives for income-qualified households. Multifamily and Commercial buildings will also be eligible for tax credits.
CalNEXT research should inform changes needed to the existing statewide HVAC and fuel substitution programs to prepare strategic alignment with the new federal programs as well as inform the direction of the new federal programs. Additionally, CalNEXT should continue to investigate HP deployment strategies specifically designed for renter ratepayers which are not well targeted by these federal programs nor current statewide program offerings.
Technical understanding of the HP market continues to grow through deployment programs such as BUILD (The Building Initiative for Low-Emissions Development), California Energy-Smart Homes, and the relaunched 2023 Technology and Equipment for Clean Heating (TECH) Clean CA program. The IRA will continue to accelerate these activities and current and future programs should seek alignment with federal tax credits and the HOMES and HEEHRA programs where appropriate. However, more research is needed to understand the appropriate deployment strategies and technologies for different building types, communities, and end users in order to ensure benefits for all ratepayers.
A holistic design that is aimed at achieving a high-efficiency, low-emissions HVAC system in both new and existing buildings.
Decoupled HVAC systems (e.g., High efficiency Dedicated Outdoor Air System (DOAS) with an Energy Recovery Ventilator (ERV) and Variable Refrigerant Flow (VRF)), heat recovery chillers, air-to-water HPs, and other whole system all-electric designs.
ET research in this technology family will yield strong EE savings potential and decarbonization by electrifying space heating, enabling energy recovery, or removing design barriers to future decarbonization. Prospective research should focus on: (1) developing design tools to electrify existing buildings utilizing existing studies and design guides when available, (2) conducting field studies to validate the performance and cost-effectiveness in electrifying “difficult” existing building HVAC systems such as systems using large boilers for hydronic space heating, and (3) developing program strategies for overcoming technical and market barriers.
HVAC designs have been evolving to meet the needs of a decarbonized building future. While technical understanding is growing, particularly in the new construction market, the existing building sector needs research to overcome considerable technical barriers and market complexity in transitioning these systems. Research is needed for cost effectively retrofitting and electrifying HVAC systems in the existing building market, particularly for the commercial and multifamily sector, as well as understanding the appropriate program designs and deployment mechanisms to address these technical and market barriers.
Thermal or non-electric energy storage solutions with the capability to scale and integrate with HVAC systems, including both active storage (charged and discharged with controls, e.g., hot water storage tanks) and passive storage (charged and discharge without dedicated controls, e.g., heat capacitance of building structure).
Thermal energy storage and thermally activated building systems.
Incorporating thermal storage into HVAC systems has the potential for significant demand flexibility and can reduce energy consumption by shifting HVAC cooling and heating loads to periods with more favorable ambient conditions for heat extraction or heat rejection. This shift can also result in permanent load reductions, reducing peak demand by spreading heating and cooling loads over longer periods of time and by shifting to non-peak hours. Large emissions reductions are possible with significant thermal storage by shifting energy usage to times of day with lower emissions in the energy supply. Thermal energy storage can also support and accelerate decarbonization by allowing electric heat extraction and heat rejection systems (e.g., air-to-water HPs, heat recovery chillers, etc.) to serve non-simultaneous heating and cooling loads commonly found in larger HVAC systems. Prospective ET studies should build upon the ongoing research of the CA IOU CASE Team on this topic as well as conducting lab and field demonstrations of emerging technologies with a viable path to scalability. As this is an emerging technological space, there is a need for new market studies to characterize different emerging product types and their uses for particular building types and HVAC system typologies.
Significant technical and market barriers exist, including high capital cost, added complexity of design and controls, lack of available space for equipment, risk of equipment failure, lack of cross-trade coordination, particularly for storage systems with significant space requirements or those that integrate directly with a building structure. Thermal storage ideas and projects should identify barriers and provide strategies for mitigating or removing such barriers.
Efficient, rapidly deployable HPs that often do not require professional installation and are suitable for compact spaces where HPs can replace electric space heaters or where traditional split-systems are too costly or onerous to deploy. Typical scenarios include small homes, additional dwelling units, apartments, mobile homes, hospitality, assisted living facilities, and schools. This technology family will help meet the California Energy Commission’s goal of installing at least 6 million HPs by 2030.
Portable HPs, window HPs, packaged-terminal HPs, and through-the-wall HPs.
Mass deployment of 110V/120V HPs has the potential to rapidly electrify space heating and simultaneously replace existing portable space heaters and older, less efficient room air conditioners with more efficient HPs. Advancements in this technology family may be especially important for DAC and HTR customers since they are a majority renter group with limited options to improve their HVAC infrastructure. These products have the potential to provide a low up-front cost alternative compared to traditional central heat pump systems that is significantly more efficient than current systems (portable electric resistance heaters and gas-fired heaters). Prospective ET studies should investigate deployment costs of 110V/120V HPs when compared with more traditional HVAC solutions and investigate in-field heating performance of these products to ensure they can fully displace existing electric resistance heaters since these products have historically been optimized for their cooling performance rather than their heating performance. Studies investigating customer usage patterns may also help inform the real-world efficiency and electrification potential of these products.
Most 110V/120V HP products are adaptations of familiar products such as room air conditioners or portable air conditioners. ET investments in this technology family can help better understand product costs compared with similar heating/cooling devices, product usage patterns, customer sentiment, and market availability. Installation is often performed by users so identifying common installation challenges would be appropriate (e.g., setting of outdoor air damper position, sealing around unit).
This technology family is focused on advancements in HVAC commissioning techniques and improvements in installation, operations, & maintenance focused on improving the initial energy performance at time of installation, ensuring persistence of performance, improving the useful life of HVAC systems through proper maintenance. This technology family has strong overlaps with the Scalable HVAC Controls technology family.
HVAC System Commissioning (Cx), Existing-building Commissioning (EBCx), asset management, benchmarking & monitoring, building performance standards, flexible load management, and artificial intelligence (AI) building management systems.
Improvements in installation, operations, and maintenance have moderate potential for energy savings, demand flexibility, and can reduce refrigerant-related emissions. Under a 2020 Lawerence Berkely National Lab (LBNL) study, research found median simple payback time for EBCx to be under 2 years yet despite the benefits, initial cost remains a significant barrier. The continued maturity of Normalized Metered Energy Consumption (NMEC) programs have the potential to improve program delivery within this technology family.
Prospective research should focus on: (1) demonstrating low-cost approaches to existing building commissioning, continuous commissioning, and quality installation programs; (2) demonstration of tools to help small and medium building operators incorporate sophisticated asset monitoring; and (3) improvements to existing program models to improve the quality of installations, maintenance practices, and ultimately the persistence of energy efficiency measures.
Technical understanding of installation, operations, and maintenance is a mature area. To date, adoption of Cx has been mostly driven by mandatory building code requirements or voluntary code requirements such as California Green Building Standards (Title 24, Part 11) (CALGreen) or Leadership in Energy and Environmental Design (LEED) ratings. While research indicates that existing buildings still have significant cost-effective energy savings opportunities, deployment across building types remains a complex and disaggregated market. Utility incentive-based approaches may continue to be important to develop the market capabilities while California’s policy makers further assess systematic existing building policy approaches such as building performance standards.
Research for transitioning HVAC systems to low and ultra-low GWP refrigerants, reducing the overall refrigerant charge, reducing refrigerant leakage, ensuring adequate safety of “mildly flammable refrigerants” (A2Ls), or reclaiming refrigerant at end-of-product life.
Performance validation of low and ultra-low global warming potential (GWP) systems, refrigerant recycling strategies, refrigerant leak mitigation, low-charge system design, and low-leak pipe fittings & installations.
HVAC manufacturers are rapidly transitioning away from R-410A to “low-GWP” refrigerants with a GWP below 750 such as R-32, R-454B, and R-466A. These are substantive changes that may have a significant impact on the overall efficiency, system capacity, and legally installable refrigerant charge limits.
Highest impact research under this technology family will assist with an orderly transition of the HVAC market (including existing IOU programs) in adherence to the regulatory enforcement deadlines. This will include analyzing the impact of different low-GWP refrigerants against the baseline energy usage to avoid sacrificing overall system performance while transitioning to alternative refrigerants as well as ensuring safe installation practices for A2L refrigerants. In addition, with the shift from kW, kWh, and therms to total system benefit (TSB) as the IOU program performance metric, programs that target refrigerant emissions reductions will be able to claim savings starting in 2024. Research into new program models that focus on refrigerant emissions reductions would be valuable. CPUC has undertaken research to this effect in recent years, ET work should build on their findings.
Note: Refrigerant management of ammonia (R-717) and CO2 (R-744) are discussed separately in the Process Loads TPMs as they are not currently used in HVAC systems. However, we are aware of early-stage product development using these refrigerants targeted for the HVAC market.
Technical performance of systems with the new refrigerants is not well known as manufacturers are still developing new products. Building codes, in particular the mechanical code (Title 24 Part 4), are in the process of being updated to safely allow the use of mildly flammable refrigerants. Any changes in the installation, maintenance, or handling of new refrigerant systems will have to be disseminated for workforce development programs.
Please refer to the Emerging Technologies Coordinating Council for a complete list of active and completed projects to ensure your project is not duplicative.