We have several different experimental heating systems here at CCHRC including a ground source heat pump. Popular in the lower 48, heat pumps are increasingly common heating appliances in Alaska that can be used for both heating and cooling. Heat pumps work like a refrigerator in reverse. Pipes are laid in the soil outside and liquid (a mix of glycol and water) is sent through the pipes. As the fluid travels it gathers heat from the soil, goes through a compressor, and into a refrigeration cycle to “bump up” the temperature of the fluid. The compressor uses electricity to raise the temperature for space heating, at CCHRC we use 90°F temperatures in our radiant heat system. Ground source heat pumps are still experimental in Alaska because our soils are so cold and we don’t have a cooling system so we use the sun to heat the ground in the summer.

While ground source heat pumps are gaining popularity in cold climates, there are still questions about how they perform in cold soils. To help answer these questions, the CCHRC installed a ground source heat pump at the RTF in November 2013. The demonstration ground source heat pump replaced an oil-fired boiler and is heating office space in the building. Researchers are monitoring the heat pump for a 10-year period to study how its efficiency changes over time and how it affects the temperature of the ground.

So far we’ve found that they’re expensive (~ $30K), and require lots of dirt work. A boiler or furnace is less expensive. We’re currently looking at whether they create permafrost.