High-Performance Air-source Cold Climate Heat Pump (CCHP)
Dr. Ahmad Mahmoud | United Technologies Research Center
In response to Environmental Security Technology Certification Program (ESTCP) Broad Agency Announcement (BAA) fiscal year (FY) 2017, and in support of Energy Policy Act (EPAct) 2005 and Executive Order (EO) 13423, United Technologies Research Center (UTRC) proposes to demonstrate a nominal 10 Ton of Refrigeration (TR) high-efficiency cost-competitive Cold Climate air-source Heat Pump (CCHP) system at two Department of Defense (DoD) installations in relevant climate zones. The proposed CCHP shall enable up to 20% annual space cooling and heating energy savings, in American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) climate zones 4A to 7 while meeting the current pricing of state-of-the-art (SOA) mid-tier heat pumps. The demonstrations will be conducted at the Maine Army Reserve National Guard headquarters at Camp Keyes in Augusta, ME and the Marine Corps Mountain Warfare Training Center in Bridgeport, CA. This project aims to 1) bring the prototype CCHP components and system to technology readiness level 8(TRL8), (2) demonstrate > 20% relative decrease in annual energy consumption over state-of-the-art systems and (3) demonstrate site autonomous operation of the prototype CCHP, operability and functionality.
The proposed system will improve on state-of-the-art (SOA) industry standard heat pumps that can degrade by up to 60% in capacity and 50% in system efficiency (COP) at extreme heating conditions. Two key enabling technologies, high-efficiency high-lift compression and system level design optimization for cold climates enables this performance. High-fidelity analysis was previously used under a U.S. Department of Energy (DOE) program to advance and demonstrate system performance over a wide range of ambient conditions, delivering heating performance at low cost while maintaining cooling performance. System-level optimizations would extend temperature range and minimize cold-blow. The proposed heat pump would be scalable beyond 40TR, cost effective with no change to footprint and installation complexity.
In addition to the up to 20% annual energy savings, supporting the DoD energy security and energy efficiency goals, tangible benefits from the proposed project include the following:
Institutional Scalability: The 10TR air-source CCHP proposed is unique in that it allows high efficiency and high capacity operation over a wide-range ambient temperatures and modes of operation. This enables technology deployment in several climate zones within the U.S. United Technologies Research Center (UTRC) projects that > 56% of DoD installations are located in areas where a CCHP is a viable heating and cooling solution. The proposed CCHP is readily scalable from the 5TR to 12.5TR+ sizes which are currently the highest volume packaged rooftops installed at DoD bases.
Remote Heating Solution: The DoD supports a great number of facilities, across all military services, throughout the globe in strategic cold climate regions. In many instances, these facilities are in remote areas that are far removed from the natural gas grid. Logistics associated with the transport of heating oil or propane might also be challenging. Electricity is readily available across most locations. Current limitations (capacity, efficiency and supply air temperature) in SOA heat pumps are an obstacle to wide scale cost-effective deployment of electricity based heating solutions. A cost-competitive, high-capacity and high-efficiency CCHP solution could change the logistical costs burdened by the DoD associated with heating.
Annual Energy Savings and Payback: Projected savings vary significantly depending on the age and retrofit status of the building being analyzed. As a result of increased capacity and efficiency, the proposed system is predicted to have up to 20% annual reduction in HVAC energy consumption across relevant climate zones. This represents a potential annual energy savings of 14 trillion British thermal unit (Btu) and $61 million. Additional savings associated with the price volatility and dependence on hydrocarbon fuels is not factored here. Additional $2.3B annual energy cost savings can be had with successful widespread deployment of the proposed CCHP for commercial US building stock in the relevant zones (4A to 7).