PUBLISHED: 4:47 PM on Wednesday, June 11, 2008
Renewable heat
Brain Power
Spring 2008 at the Cold Climate Housing Research Center (CCHRC) marks a new era in northern building energy use: for the first time, a research-based solar hot water system is making hot water from the sun despite frigid March temperatures in the Interior.

Thanks to hard work from Dave Shippey and the rest of the CCHRC staff, the Heliodyne flat plate solar hot water collector system was completed in February and has made water up to 115?F before the 2008 equinox. The Heliodyne collector uses a photovoltaic-powered pump to move hot glycol from the panel, which is located on the western part of the roof, to the side-arm heat exchanger mounted on a 50-gallon electric hot water tank located in the north research lab. The Heliodyne panel is a 4x8 panel (called a Gobi 408), and thanks to the PV pump, does not require any electronic controls. The Heliodyne system provides tempered water supply to a gas-powered, on-demand water heater with a modulating burner. The system has worked extremely well so far, and we look forward to seeing how hot the water can get so we can test the anti-scald devices that were installed to make the system truly plug-and-play.

While in the past most Alaskans who have toyed with solar thermal technologies have been cutting-edge types, such as the famous Mr. Weidner of Fairbanks or Mr. Bowers of Palmer, researchers at CCHRC are attempting to make solar thermal a convenient way to save money. Adding a solar water heater will allow Alaskans to turn off that noisy boiler during the summer.

A Thermomax 20-tube evacuated tube water heating system was completed March 19. March 20 was the first day that the tubes were making hotter water than the Heliodyne; the outdoor temperature was around zero in the morning, with strong sunlight starting in late morning. Cold temperatures with lots of sunlight are the optimal conditions for evacuated tube performance, and we got the first sense of what that might mean for the research system.

The Thermomax collectors are linked to a 120-gallon tank-within-a-tank water storage system in the north lab. A wand heat exchanger exchanges heat from the glycol working fluid to the tank. The heated water is linked to a sophisticated control system by Siemens Building Technologies that considers the outdoor temperature and the temperature of the water storage tank to make a decision to open a motorized 3-way valve to bypass the boiler and supply solar heated water directly to the radiant hydronic heating system throughout the building. Because all decisions about using the heated water are automated, this setup is aimed at discerning homeowners who don't want to spend a lot of time maintaining the heating system in their homes, but who are interested in saving money on energy costs. And since space and water heating are the primary energy costs for an Alaskan family, we are excited about solar thermal's potential for contributing to the Alaskan economy.

A third solar thermal (also known as solar hydronic) system on the roof at CCHRC aims to solve a simpler problem. The center unit, a flat-plate, roof mounted tank made by Solahart, is the kind of water heater commonly seen in warmer climes such as Israel, Latin America, and southern Europe. The goal for this water heater was to compare the economics of a summer-only system with the year-round Heliodyne and Thermomax units.

All three systems were installed in May 2007 as part of the solar thermal training course developed as a joint effort by CCHRC and Cooperative Extension Service, and funded by Golden Valley Electric Association (GVEA). The course has resulted in a trained base of installers throughout the state, from Kenai to Anchorage and Fairbanks. A list of solar installers who took the May 2007 training is available at

Solar is the single largest energy source available to the world, providing enough energy in a single day to power all human endeavors throughout the entire world. The issue is merely how to capture this elusive energy source.

Garrison Collette is an Energy Assistant with the Cooperative Extension Service at the University of Alaska Fairbanks.

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