The Colorado State Capitol building in Denver achieved $95,000 in first-year utility bill savings after undergoing an HVAC system retrofit, HPAC Engineering reports.
The Colorado Capitol Complex was slated for a major renovation and restoration by the Colorado Department of Personnel & Administration (DPA) in 2003. Under the state’s Renewable Portfolio Standard (RPS), Colorado is required to use 30 percent renewable energy by 2020, so the DPA sought a retrofit solution that would increase the energy efficiency of the buildings and also incorporate renewable energy.
DPA worked with Chevron Energy Solutions (CES) to plan $30 million in upgrades to the governor’s residence, the Colorado Department of Revenue building and the Colorado State Capitol building.
For the State Capitol building, CES designed a $6 million hybrid system that integrates a 23-ton geothermal heat-pump system with a 10-kW solar PV system. A network of nine ClimateMaster water-to-air and water-to-water heat-pump units were integrated with an open-loop geothermal system utilizing the Arapahoe Aquifer, located about 900 feet below the State Capitol building.
The geothermal system was funded by a $4.6 million US Department of Energy grant and $1.4 million in state-funded certificates of participation and a lease-purchase agreement with CES.
By 2029, the system will save an estimated $165,000 per year in energy costs. The system has an estimated payback period of 10 years.
Other energy-saving improvements at the complex included installing energy-efficient lighting systems and making building-envelope improvements.
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