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Colorado Capitol Goes Geothermal

Linda Hardesty

Colorado capitolThe Colorado State Capitol is a complete mess right now as the building gets new gold leaf on its dome and a new geothermal energy system.

Colorado will be the first state capitol in the country to have a geothermal system for heating and cooling. The only other state capitol using geothermal is Idaho’s building, which is heated from a hot springs.

The work in Denver is being performed via an energy performance contract with Chevron Energy Solutions. The company has drilled an 865-foot well under the state capitol to run a pipe into the Arapahoe aquifers below the building, tapping into the 65-degree waters.

The Department of Personnel & Administration, which is overseeing the project, says the geothermal units have been brought online and are now in the process of being commissioned and balanced. In addition to the upgraded functionality of air conditioning to the building, the project is replacing existing pumps and other equipment that date back to the 1940s and are well beyond their estimated useful life, avoiding about $904,000 in replacement costs.

The open-loop geothermal system is expected to save about $100,000 in heating and cooling costs in the first year, reports the Denver Post.

The US Department of Energy is providing a $4.1 million grant toward the overall $5.5 million project. The state is financing just under $1.5 million to complete the project.

Meanwhile, the capitol dome renovation project, which includes burnishing new gold leaf, will be complete late summer or early fall 2014.

The Colorado Capitol is the only state capitol to be LEED EBOM (Existing Building Operations and Maintenance) Certified by the US Green Building Council. It achieved that status in 2008.



9 comments on “Colorado Capitol Goes Geothermal

  1. What a great idea however, I wonder HOW many motors, pumps and other equipment is required to get the water to the surface at pressure and then clean it for use? Where do the waste products go and what affect on the environment will they have? Are we putting MORE carbon via increased electrical usage, into the atmosphere than would normally be required if we simply used natural gas or better yet, electricity? I would like to see these articles address these findings.

  2. Don’t know about how many pumps, etc.; but I can say the following.
    1) The water probably does not need to be cleaned at all – it is merely to be used as a heat exchange fluid.
    2) There are no waste products produced in a closed-loop geothermal system. In a closed-loop system, a single (plastic) pipe gets bent into a loop and the loop is lowered into the well such that the two loose ends protrude out the top and form the supply and return lines of the well. The water circulated into and out of the well is contained within the pipe; it is not exchanged with the water in the aquifer, nor is it released into the environment at any other point.
    3) The system will definitely put far less carbon into the atmosphere, because it will require virtually no burning of any fossil fuel outside of any burned to produce the electricity to run the system.
    4) Very little electricity will be required to circulate the water in the well pipe, because of the water pressure balance achieved between the supply side and the return side of the well (both columns of water balance and to move the water one merely has to provide impetus to overcome friction with the pipe walls).

  3. Oklahoma State Capital system was installed in the early 90′s. Floors 1-4 were 100% Geothermal, additional 2 floors were added to the system which caused need for cooling tower/heat exchanger addition.

  4. An open loop system, as described in the article, would circulate water from the aquifier, through the building and back into the aquifier. This open loop arrangement would require more filtering and pumping than the closed loop system accurately described by “Doug” on July 23, 2013 at 2:58 pm.

  5. In response to Carbon Neutral: As Doug mentioned, this is a closed system and no interaction with the water table occurs. The pumps/etc are usually not much different in size than conventional pumps. As far as your request to use electricity, thats exactly what geothermal uses in addition to natural heat imbalances. I agree with your criticism in general however, I dont always agree that these are the best systems. They usually require subsidization and LCCA prove they are not economically feasible.

  6. A geothermal application with the lowest cost and highest efficiency – viz. open to diffusion well system. Open-diffusion is the oldest (our knowledge, 1938). Of the three earth couplin gmethods, it is the premier method for geothermal heat transfer, when site geology permits.. Cudos to the designers and practical cost aware owners. A wonderfulo example to counter the negative statment that “geothermal heat pumps are expensive” ,

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