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CSU Moby Arena


2020 Project of the Year

For the Mountain States. Click here to watch video.


Energy Use Reduction

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Energy Cost Reduction

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Project Goals

Moby Arena has relied on heating from the steam system that was built in 1960.  The steam system had significant leaks and returned minimal condensate back to the central plant located near the CSU Oval.   This system was carbon-intensive, and heating capacity was needed elsewhere to support an aggressive expansion program on campus.  

CSU was looking to disconnect the campus steam system from the sport complex completely.  This led to GeoX, a decade in the making project that replaced the 60-year-old high pressure steam and cooling lines in Moby with a six-pipe geo exchange system.   

The effort to reduce Moby’s carbon footprint fits into CSU’s goal of moving to 100% renewable electricity by 2030 and reaching carbon neutrality by 2040.


U.S. Engineering worked with CSU on the campus’ first Geo-X system, which serves the heating and cooling needs of the Moby Arena Complex – projects crucial to CSU’s commitment to achieve carbon neutrality by 2040. The GeoX installation will be the largest ground-source heating and cooling system in Colorado and one of the largest in the western United States.

  • Building Area:  261,623 square feet
  • Two new central plants
  • Five six-pipe modular heat pumps
  • 1,200 tons of cooling
  • Largest geofield in Colorado
  • 342 wells @ 400 feet deep each
  • 70 miles of u-shaped condenser water piping

Project photos and images

Energy use reduction

The figure below summarizes the total energy use for the Moby Complex, including electricity, steam and natural gas combined.  Total energy usage in 2021 has been reduced in this 5 building complex by 56% on average compared to 2018 and 2019.  A large portion of this savings can be attributed to the mechanical system upgrade.  Energy savings are more noticeable during the cooler months, which demonstrates the energy efficiency of providing heating water through the heat pump system compared to traditional steam systems.

Energy cost reduction

The figure below compares the total energy cost for the Moby Complex of all utilities before and after the GeoX project.  Total energy cost has been reduced by 28% on average compared to 2018 and 2019.