University Power Plant
District Energy
The University of Iowa’s main campus and the University of Iowa Hospital and Clinics complex are served by a large district energy system. District energy involves production of steam, electric power, and chilled water at central utility plants for distribution to buildings through a network of underground pipes and electric cables. The UI is recognized in the EPA Top 20 list of on-site green power users (2009 and 2010)- Press Release.
District Energy Portfolio
- Combined Heat and Power System (Co-generation)
- Distribution Systems
- Chilled Water Production
- Purchased energy by type and cost
Combined Heat and Power System
The University of Iowa Power Plant, located at the corner of the Iowa River and Burlington St., is a Combined Heat and Power (CHP) facility. Fuels burned at the Power Plant include coal, natural gas, and oat hulls. The plant co-generates about 20-percent of the total electric power needs and produces all the steam energy used throughout the campus and hospital facilities.
CHP, also known as co-generation, is an efficient, clean, and reliable approach to generating power and thermal energy from a single fuel source. CHP is not a specific technology but an application of technologies to meet an energy user's needs. CHP systems achieve typical effective electric efficiencies of 50% to 70% — a dramatic improvement over the average efficiency of separate heat and power. Since CHP is highly efficient, it reduces traditional air pollutants and carbon dioxide, the leading greenhouse gas associated with climate change, as well.
The University of Iowa is a member of the United States Environmental Protection Agency CHP Partnership. The CHP Partnership is a voluntary program that seeks to reduce the environmental impact of power generation by promoting the use of CHP.
Distribution Systems
Mechanical Distribution
Mechanical Distribution maintains all of the University's steam, chilled water and domestic water piping. In addition to these systems, Mechanical Distribution is responsible for over 200,000 feet of storm and sanitary sewer.
The Main Campus steam system operates at 155 psi and 20 psi. The Oakdale Heating Plant delivers steam at 125 psi. All three systems contain over 140,000 feet of steam and condensate return pipe ranging in size from 1 to 24-inches. Most of the steam and condensate return pipes on the Main Campus are in the steam tunnels. Mechanical Distribution maintains nearly six miles of tunnels.
Electrical Distribution
Electrical Distribution maintains most of the high voltage equipment on campus. This system includes 250 vaults, 20 miles of underground ducts and 66 miles of cable.
Chilled Water Production
In 1970, the University opened its first central chilled water plant. Located in what is now Hospital Ramp 3, the West Plant provided 4,520-tons of cooling to the Health Science Campus. Since then, the system has expanded to include three plants and three satellite chillers for a total capacity exceeding 40,000-tons.
The most common use of chilled water is air conditioning. Building air handlers use water from the central plants to cool air and provide comfort cooling. In recent years, the plants have seen an increase in process loads. Computers and research projects all over campus use chilled water for temperature control.
The West Plant is still the largest chilled water facility on campus. At this time, all of the 18,500-tons of capacity come from centrifugal chillers powered by electrical motors. The plant is completing an update that has added three 4,000-ton steam-driven chillers.
The Northwest Plant houses the largest chiller in the University’s inventory. The 5000-ton unit is similar in operation to the West Plant chillers. The only difference is that a steam turbine powers this unit’s compressor.
The North Plant has a variety of chillers including two steam absorption units. Absorbers use water as a refrigerant (centrifugal units use chemical refrigerants) and rely on a chemical reaction to produce chilled water. Total capacity of the North Plant is 6,200 tons.
Underground piping connects nearly sixty buildings to the chilled water plants. Water pumped from the plants travels to the buildings through supply lines. Warm, used water flows back to the plants through return lines. The entire system is a closed loop, water continually cycles between the plants and buildings.