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Constructed in 1945, the Power Plant for the University provided steam generated heat using three coal/woodchip fueled boilers to various facilities throughout campus.
In 2010, University personnel partnered with the consulting team of McClure Engineering and CM Engineering to study feasibility of replacing the old steam infrastructure with a ground-source heating system, and to determine the impact such a system would have on campus. The study assessed placement for well fields and corresponding underground loops along with current building system conditions and how best to implement such a dramatic change without causing severe disruption to campus life.
The Missouri University of Science and Technology designed an integrated ground-source energy system, a project that created three new geothermal heat-exchanging plants to serve the heating and cooling needs for over 1,000,000 square feet of conditioned space within 17 buildings. These buildings encompassed classrooms, laboratories and offices. Other spaces served solely by the geothermal cooling system include additional classrooms, laboratories, apartments/dorms and a student center.
The system includes 645 vertical bore wells, each 400 to 440 feet deep, combined into closed loops serving the three plants housed withing Straumanis-James, McNutt and Bertelsmeyer Halls. Each plant contains 500 tons of Heat Recovery Chillers (HRCs), cooling towers for supplemental heat rejection and gas-fired boilers for auxiliary heating.
In addition to the three main geothermal plants, an additional system was created in the Gale Bullman Multi Purpose building/Student Recreational Center. This system included 144 vertical bore wells drilled to the same range of depth as the primary well fields, and augments the center's HVAC and pool-heating systems.
The geothermal system uses the Earth's thermal mass to store rejected heat during the warmer months and extract it during the cooler months via underground hydronic loops. This project eliminated the deferred maintenance of the 40 year old coal/wood chip-fired steam boilers, associated subterranean steam and condensate lines, and other related equipment in the power plant. Additionally, a two-pipe chilled water system, sized for future expansion, replaced the aging single-pipe chilled water loop.
The buildings utilizing the steam plant and single-pipe chilled water loop had a carbon footprint of 99.6 million lbs of carbon dioxide each year. Implementing the geothermal campus system was anticipated to decrease this footprint by up to 50%, bringing the University much closer to its goal of carbon neutrality. The system was also projected to save 10 million gallons of water each year.
The geothermal system was anticipated to cut total energy use of the education & general campus buildings in half and save $1.1 million per year in operational costs for a 27 year payback. The project also modernized campus infrastructure by incorporating over $15 million in deferred maintenance. An additional $46 million of deferred maintenance tasks were rendered obsolete by the project and subsequently eliminated from the budget. The system has been in operation since July 1, 2014. Utility bills have shown energy savings of approximately 57% compared to recent years and roughly $100,000 saved in water costs.
Read more about this project in the McClure Paper.
The geothermal project schedule is outlined below. The system has been in operation since June 2014.
|Northeast Loop Well Fields & Geothermal Piping
|Northwest Loop Well Fields & Geothermal Piping
|South Loop Well Fields & Geothermal Piping
|Trenching & Individual Building Work
|Northeast Loop Plant Construction
|Northwest Loop Plant Construction
|South Loop Plant Construction
|Bertelsmeyer Hall Construction
|Decommission Power Plant
The project included the installation of ground source heat recovery chillers, construction of a geothermal "earth-loop", well fields, heating/cooling water distribution loops, and required modifications to building HVAC systems. This project created three geothermal regional plants. The regional plants are located in the McNutt, Straumanis-James, and the recently-completed James E. Bertelsmeyer Halls.
These plants contain screw-type heat recovery chillers and serve adjacent buildings with heating water through a new heating hot water distribution system. Supplemental boilers have been installed in the regional plant to provide first-cost savings, peak load energy savings, and flexibility of energy usage. The heat recovery chillers also are connected to the cold water distribution system to provide the base cooling source. The chilled water distribution system has been modified and upgraded into a two pipe system. The system reuses the existing electric chillers and cooling towers located on campus, which have been reconfigured to work with the new chilled water distribution system. The cooling towers allow extra heat to be disbursed in the atmosphere, ensuring the well fields will not become unviable for cooling needs due to heat-saturation.
The benefits of regional plants include less infrastructure maintenance, longer equipment life of screw chillers compared to modular type, and adaptability to load diversity between buildings.
To reduce piping costs and simplify phased growth of the campus geothermal system, each regional plant has been tied to a dedicated well field. The well fields have been sized to optimize the payback from utility savings.
Buildings not in the scope of this project that had used steam from the power plant for heating have been retrofitted with dedicated steam boilers or upgraded with other systems until those buildings can be added to the future geothermal plants.
The stated goal for water usage was to save 10 million gallons with the installation of the geothermal system. First-year water savings totaled over one-and-a-half times the projected goal at 18.7 million gallons, with nearly half of that amount resulting from shutting down the old power plant.
The dark green portions of the stacked bar graph below represent water usage directly affected by the geothermal project. This usage came from two areas on campus: the old power plant, and rooftop cooling towers associated with the conventional chiller units now augmented by the new geothermal system.
Differences shown in the blue and dark green portions were omitted from water savings calculations in order to determine the geothermal system's stand-alone impact on water use, which is calculated to be approximately 16.5 million gallons. Another estimated 2.2 million gallons of collective water savings were found throughout the buildings serviced on the geothermal loop, and attributed to repair of hidden leaks in the water mains replaced during construction (not shown on graph).
"Balance of Water Use" represents the difference shown between the usage recorded by Rolla Municipal Utilities on the 15th of each month and the in-house meter readings done by S&T maintenance staff on the final day of each month. The geothermal system is constantly undergoing efficiency evaluation during the course of its operational service life. The data collected is then used to fine-tune system parameters and maximize future water savings over time.
Before the geothermal system was in place, the power plant provided steam to the campus for most heating and some cooling needs. Additionally, the plant also supplied a small percentage of campus power. Once the geothermal system was operational in May of 2014, the power plant's coal and wood-fired boilers were shut down and decommissioned.
The geothermal system provides heating and cooling to the campus through hot and chilled water distribution systems. Today, all electricity used on campus is delivered by the local municipal utility, of which80% is renewable wind energy.
Due to the efficiency differences between combusting fuel to produce and distribute steam versus utilizing heat recovery chillers connected to geothermal well fields, the anticipated savings for the project was a reduction of 50% of energy consumed on the campus. During the first year of operation, the geothermal system reduced total energy use by 57% relative to 2009 and 60% relative to 2010. As the graph below clearly indicates, campus energy demand has peaked in January for the last seven fiscal years. In the two years following the installation of the geothermal system, the average January kBTU consumption fell to less than half of pre-geothermal levels, and total average monthly consumption has shrunk by 56%. 2016 saw a 1% increase in campus energy efficiency due to ongoing analysis and refinement of the system.
One of the most precious resource on the planet is the air that we breathe. Ever since the industrial age, the ability to keep Earth's atmosphere clean has increased in difficulty. One emission that has been a big factor in preventing us from keeping the Earth's atmosphere clean is carbon dioxide emissions. In 2009, a campus-wide energy audit discovered the S&T power plant was responsible for the release of 32,000 tons of carbon dioxide and upon the completion of the geothermal project and the decommission of the power plant, the burden of the 32,000 tons of carbon dioxide was immediately eliminated. Although the 32,000 tons of carbon dioxide emissions was removed from the total emissions from the university, the campus energy demand increased and so we requested , through Rolla Municipal Utilities, additional energy, most of which is provided by wind energy. By doing this, it was found that, the net reduction of carbon dioxide emissions was found to 25,017 the first year of operation of the geothermal system and in 2019 it was found that the net reduction of carbon dioxide emissions is 25,071 tons.
Three regional geothermal heating/cooling plants and an additional geothermal system for the Bullman Multi-Purpose Building / Student Recreation Center have been installed. Currently, 17 Buildings containing 1.2 million square feet of space are served by the geothermal systems. This is about 2/3 of the general & educational spaces on the campus.
The buildings serviced by each plant for heating water are in the areas colored yellow, green, and blue in the graphic. Each plant has dedicated geothermal well fields, which are indicated by hatch-filled areas of corresponding color.
Black circles indicate the three regional plants located in McNutt, Straumanis-James, and Bertelsmeyer Halls. The Geothermal loop piping is shown with black lines. The Hot Water Loop piping is indicated by red lines. The blue lines indicated the route of the reconstructed chilled water distribution system which was included in the scope of the project, and serves a most of the buildings on the main campus, including some shaded in gray.
The satellite system at Gale-Bullman Multi-Purpose Building / Student Recreation Center and associated well field are shown in pink.
No. Our system utilizes ground-source heat pumps to deliver geothermal energy to the buildings serviced on campus.
While our system is dependent on externally-provided electricity, our use of that energy has been reduced by over 50% since the geothermal system was brought online. In addition, our carbon-dioxide emissions have been reduced by 25,000 tons per year and annual water consumption was cut by over 25,000 CCF, or 18 million gallons.
645 wells have been installed for the three main geothermal plants. 144 wells have been installed for the Bullman geothermal project. The total number of wells installed is 789.
The wells range in depth from 400 to 440 feet. Average depth of the wells is about 430 feet.
The groundwater temperature in this area is approximately 60°F. As the year progresses from predominantly cooling season to heating season, the temperature of the water circulating in the closed geothermal loop will vary from 90°F to 100°F in the early fall to 40°F to 45°F in the spring.
Ground source heat pump technology has been around for many years, but only one other university has completed a project of this scale.
McClure Engineering offered consulting while Physical Facilities was evaluating feasibility.
A heat recovery chiller (HRC) operates on the principles of a refrigeration cycle: the same basic cycle that is used for refrigerators, air conditioners, and heat pumps you find in your homes. It is designed to provide both useful cooling and heating energy from the system. The work (energy) put into the machine through the compressor is used to simply transfer heat from evaporator to the condenser, which makes the design a more efficient use of energy than combusting fuel for heat.
As seen in the diagram below, refrigerate is first compressed using a screw-type compressor. This hot gas is then condensed to a liquid as it travels in a circuit through the condenser, where heat is transferred to the water flowing through the condenser tube bundle. Our system uses R-134a refrigerant as a thermal transfer medium.
The pressure and temperature of the refrigerant are reduced as it flows through the throttling valve. Next, the refrigerant passes through the evaporator where it absorbs heat from water flowing through the evaporator tube bundle. Then the cycle repeats as the refrigerant goes back to the compressor. The refrigerant is confined inside of the heat recovery chiller for the entire process.
The geothermal system provides heating in the winter and cooling in the summer. If needed, the system may also operate in a dual-production mode and provide simultaneous heating and cooling.
Heating Water Production
Water from the campus heating water return lines flows through the condenser of the heat recovery chiller (HRC) where it is heated to a nominal 120 degrees Fahrenheit for distribution back to campus. Heat is transferred from water flowing through the evaporator tube bundles, which has been circulated in the geothermal loop and warmed by the well fields.
Chilled Water Production
Water from the campus chilled water return lines flows through the evaporator of the HRC where it is cooled to a nominal 44 degrees Fahrenheit for distribution back to campus. Heat is transferred to water flowing in the condenser tube bundles, which has been circulated through the geothermal loop and cooled by the well fields.
Simultaneous Heating and Cooling
As before, water from the campus hot water return lines flows through the HRC and is heated to a nominal 120 degrees Fahrenheit. In this case, water from the campus cold water return lines provides the necessary heat transfer as it flows through the HRC evaporator and is cooled to a nominal 44 degrees Fahrenheit. Geothermal loop water is mixed as needed through either the condenser or evaporator tube bundles to balance the loads on the chiller.
|Additional: Physics Building
|Additional: Bullman Building
|Multiple projects for building modifications, chilled water loop replacement, etc.
|Sources of Funds
|University of Missouri 30 Year Bond Financing
|New Market Tax Credit Program Proceeds
|Anticipated/Estimate US Treasury Dept. 1603 Grant Proceeds
|Campus M&R Funds (over 7 years)
|Estimated Value of Deferred Maintenance Addressed By Projects
|Annual Estimated Cost Savings - FY 16:
|Growing in 30 Years to: