Daily Sentinel, Grand Junction - By Penny Stine, Wednesday, February 17, 2010 - Anyone who has ever soaked in the hot springs at Glenwood Springs, Ouray or any of the dozens of other hot springs pools in the Rocky Mountains has enjoyed geothermal energy in Colorado.
But geothermal energy is more than simply hot water springing up out of the earth, and Western Colorado is in a prime position to take advantage of it.
Geothermal resources fall into three categories: electrical power generation, direct use and geothermal heat exchange systems, also known as geoexchange or ground source heat exchange.
Geothermal heat exchange systems rely on the temperature of the ground rather than the temperature of surface springs or water below the surface to heat and cool buildings. Because the temperature of the ground remains fairly constant at about 55 degrees, it can be used to provide warmth in the winter and cooling in the summer via a series of loops buried three to six feet beneath the surface. Water or an antifreeze solution is circulated through the loops, where it is warmed in the winter and cooled in the summer. A water source heat pump and heat exchanger in the house convert it into warm air to heat the house in the winter. The process is reversed for cooling in the summer.
“The Western Slope has been one of the best places in the state and across the country for implementing those systems,” says Matt Sares with the Colorado Geological Survey. “In terms of installing geoexchange systems, the Western Slope is ahead of the front range.”
The Delta-Montrose Electric Association has been leading the way since 1997, offering special financing, education and installation packages when customers choose geoexchange systems.
The success of the DMEA program, along with utility bills that are 30 to 70 percent less than with other HVAC systems, has prompted builders and homeowners in the Grand Valley to notice and take action.
John Moir with Sunshine Development has been using geoexchange systems at the Village at Country Creek, the 55+ development in Fruita, since 2006. The reduced utility bills and more consistent, even temperatures throughout the house have proven to be good selling features for the retirement community.
Using the ground to heat or cool a building works regardless of the size of the building. The student housing complex, new classroom building and new Student Center at Mesa State College all use geoexchange systems for heating and cooling.
The college currently has three fields where loops are buried underground, with plans to create a fourth field to accommodate a retrofit of some of the older buildings, including Wubben Hall, the Science Center, the library and Houston Hall.
“The new classroom building has carbon dioxide sensors and motion sensors that help determine how many people are in the building so the ventilation system adjusts itself,” says spokesperson Dana Nunn. “That building has been classified by Xcel as the most energy-efficient building on the Western Slope.”
To sweeten the pot, the federal government allows a tax credit of 30 percent of the cost of a geothermal system. If a system costs $15,000 to install, homeowners can receive a $4,500 credit.
It is possible to retrofit existing homes if they’re on a large enough property to bury the loop system required for geoexchange.
“Any home that heats with propane is a good candidate for a geo retrofit,” says Harold Warth with Intermountain Energy. Warth has been designing and installing geoexchange system for seven years, getting his start with the DMEA.