ASLC shifting 98% of the Center's heating needs from fossil fuel to ocean water as source heat
April 22, 2016

Seward, Alaska (Updated: May 23, 2016) – The Alaska SeaLife Center (ASLC) is pleased to announce implementation of a ground breaking CO2 refrigerant heat pump system, realizing the goal of shifting 98% of the Center’s annual heating needs from fossil fuel to ocean water as source heat. Seven years in development, and achieved in two phases, the new system utilizes sea water from Resurrection Bay to heat the 120,000 square foot facility, dramatically slashing heating costs and carbon emissions.
This is the first installation of CO2 refrigerant heat pumps to replace oil or electrical boilers in a conventional heating system in the United States. The ASLC estimates the Center’s heat pump systems save as much as $15,000 per month, with an annual carbon emissions reduction of
1.24 million pounds per year in comparison to the original oil fired boilers.
“This project reflects the core mission of the Alaska SeaLife Center “to generate and share scientific knowledge to promote understanding and stewardship of Alaska’s marine eco-systems,” said Darryl Schaefermeyer, ASLC Special Projects Director. “It illustrates the broad and tangible ways in which our day to day work can contribute to the long term health and sustainability of the City of Seward, the State of Alaska and the global community.”
According to Schaefermeyer the heat pump system is also providing much needed cooling of both mechanical and electrical rooms in the building. Waste heat recovered from these rooms is returned to the heat pump system, avoiding the cost of conventional cooling.
Designed by Andy Baker of the Anchorage consulting firm of YourCleanEnergy, with assistance from Mechanical and Electrical Engineers from Anchorage-based EDC Inc., the 80-ton trans-critical CO2 heat pump system pushes seawater through a titanium-plate heat exchanger, returning cooled seawater to the ocean and converting captured heat through a high pressure system that is ultimately blended into the main building heat loop, circulating through all office baseboards at 160°F.
“The big news in the final implementation of the system is the use of trans-critical CO2 heat pumps. This is absolutely unique in the field,” said Baker. “We were delighted to work with the ASLC on this project.”
The first phase of the project involved installation of a 180 ton heat pump system that utilized a synthetic refrigerant known as R-134a, which has some greenhouse warming potential. In
Phase II of the project, CO2 refrigerant replaced R-134a, dramatically reducing the potential environmental impact of the system.
Once captured, the heat from seawater warms a mixture of glycol and water. The glycol then passes through four parallel heat pumps where it comes into contact with 99.9% pure CO2 refrigerant. The CO2 boils and the vapor is compressed above its critical point to 2,000 psi which raises its temperature. The hot high-pressure CO2 passes through a gas cooler, heating hydronic water to 194°F. Finally, the hot water is then blended into the main building heat loop.
“As a mission driven non-profit organization, this project is doubly important,” said Tara Riemer, President and CEO, Alaska SeaLife Center. “We are benefitting the environment and saving money at a time when both are very critical.”
The ASLC project was realized through funding from the Denali Commission Emerging Energy Technology Program, the Alaska Energy Authority Renewable Energy & Emerging Energy Technology Fund, the M.J. Murdock Charitable Trust and the Rasmuson Foundation.
About the ASLC
Opened in 1998, the Alaska SeaLife Center operates as a private, non-profit research institution and public aquarium. It generates and shares scientific knowledge to promote understanding and stewardship of Alaska’s marine ecosystems. The ASLC is an accredited member of the Association of Zoos and Aquariums. To learn more, visit
High resolution photos available from; 907-224-6397.
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