A zero GWP heat pump and distribution system for all-electric heating and cooling in California
Develop and demonstrate an advanced heat pump system that uses ammonia as the primary refrigerant and carbon dioxide is used both as a refrigerant and as a distribution fluid.
Electric Power Research Institute, Inc.
Recipient
Palo Alto, CA
Recipient Location
13th
Senate District
23rd
Assembly District
$874,604
Amount Spent
Active
Project Status
Project Update
The project team finished collecting the remaining data from the lab prototype tests and completed a Final Report detailing the key findings and lessons learned from this project.
The Issue
Heat pumps in the California climate are ideal substitutes for natural gas space heating. Unfortunately, the heat pumps available today use high global warming potential (GWP) refrigerants whose leakage into the atmosphere over time has the potential to offset any gains made by decarbonizing space heating. Currently, there is no commercially available technology that combines a reversible heat pump with near-zero GWP refrigerant at costs competitive with conventional refrigerants.
Project Innovation
The recipient is developing, testing and demonstrating an advanced heat pump system that will reduce energy demand for multi-family (MF) or small to medium commercial (SMC) applications. The proposed system’s refrigerating capacity is between 10 to 20 tons. This innovative reversible heat pump system uses ammonia (NH3) and carbon dioxide (CO2) in a unique way: NH3 is the primary refrigerant, while CO2 is used both as a refrigerant and as a distribution fluid, depending on operating mode.
Project Goals
Project Benefits
This project would have resulted in several ratepayer benefits. The high efficiency low GWP heat pump systems would have reduced space conditioning costs and peak electricity load while also potentially lowering operational costs by using inexpensive refrigerants. Switching to low GWP refrigerants greatly reduces the impact to the environment should it leak into the atmosphere; therefore, mitigating the impact to public health over conventional refrigerants.
Affordability
The proposed system provides energy savings over conventional heat pump systems. It offers reduction in refrigerant cost. Because NH3 and CO2 are readily available natural refrigerants, they are inexpensive compared to HFCs. The improved energy efficiency of the heat pump system compared to conventional systems would have resulted in a reduction in cooling and heating costs.
Environmental Sustainability
The average annual refrigerant leakage in commercial HVAC systems can be up to 10%. Since CO2 and NH3 are natural refrigerants with zero or very low GWP, this system has the potential of reducing or eliminating the impact on climate change due to refrigerant leakages. Compared to R410a leakages, the CO2e emission savings for this system can be up to 9.6 million tons, or approximately 22% of the CO2 emissions from the electricity industry in CA.
Reliability
The advanced heat pump system could reduce the electricity peak cooling load, greatly benefitting a capacity-constrained system, especially in view of recent shutdowns of major transmission corridors due to concerns about fire prevention.
Safety
Ammonia leaks are easy to detect, providing a self-alarming mechanism due to its pungent odor at levels less than 10 ppm (while R410A is odorless). Due to the high-pressure CO2 distribution loop, ammonia would not leak into the occupied space.
Consumer Appeal
In light of wildfires in recent years, more consumers are aware of the need for action against global warming. The proposed system provides them with a green, decarbonizing solution that can reduce their environmental impact.
Economic Development
There is a great need for innovative technologies in the HVAC industry as conventional refrigerants are phased out. The proposed system, once commercialized, will create numerous manufacturing jobs, as well as provide potential energy savings of $550M per year in CA that will flow into the economy, assuming full market penetration.
Key Project Members
Aaron Tam
Matthew Robinson
Subrecipients
San Diego Gas & Electric Company
Optimized Thermal Systems, Inc.
Match Partners
San Diego Gas &
Electric Company
Southern California Edison
Southern Company Services, Inc.
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