Geothermal wells to save energy
March 11, 2012
By Pat Forgey | JUNEAU EMPIRE: After weeks, or even months of preparation, Alaska well driller Tim Hlavnicka sank his first well Friday and hit nothing but gravel. He was thrilled.
Hlavnicka’s company, Aquasource, was drilling the first of the wells for the new Library, Archives and Museum building’s innovative geothermal heating system.
The ability to use geothermal there is both helped, and possibly hindered, by the new building’s location on fill, over what used to be the ocean. Because of the site’s unusual history, Hlavnicka didn’t know what he was going to find.
“There could have been oil tanks, washing machines, there’s no telling what they might found down there,” said Sen. Dennis Egan, D-Juneau, who has been following the project closely.
Use of geothermal heat to augment the building’s baseline heating system of traditional fuel oil boilers will help keep the project’s future heating costs down, said Brian Meissner, architect with ECI/Hyer, Inc.
“From the people of Juneau, the message we heard was be smart about energy efficiency, and make use of the assets that are there,” he said.
The building uses a specially designed heating system that not only has to keep artifacts and documents in perfect condition, but also keep visitors and staff comfortable as well. And it has to do that in Juneau’s sometimes nasty weather.
Coming to the rescue is the site itself. Unlike many other geothermal sites, the museum site between Egan Drive and Willoughby Street is on fill where the water table goes up and down with the ocean.
“This site used to be bay — now it’s land,” Meissner said.
Gastineau Channel water flowing through the gravel fill Aquasource found means the water table into which it is drilling is constantly being refreshed, he said.
A traditional ground source geothermal system would have taken two or three hundred wells, Meissner said.
“We’re able to do this with two wells, but were going to do a third one for redundancy,” he said. “In case we ever have a problem, (we can) turn on our third well,” he said.
The highly efficient system is made possible by the location, he said.
“We’ve got this aquifer that’s being recharged by the moon,” Meissner said.
They pump the seawater from the wells through a heat exchanger to capture the difference. Read more