Location: Klamath Falls, OR
Climate: B5-Cold Climate (i)
Built Context: Rural
Building Area Managed by the Geothermal Heat Exchange System: 400,000 sq. ft. (ii)
Outdoor Area Managed by the Geothermal Energy System (Snow Melt System): 150,000 sq. ft.
Facility Service Area: 11,000 sq.ft.
Project Time Range: 1947-2014
Geothermal System Component: Geothermal Power Plant & Mechanical Heating System
Back to 1960s, Oregon Institute of Technology campus already started to take the advantage of the geothermal resource underneath of Klamath Falls. To push the renewable energy use on campus to its limit, the university made additions to its geothermal system that allowed it to better utilize the natural resources below. The geothermal system on site would be available for student, faculty research projects, and also, as a demonstration site for interested investors and developers who want to expand their businesses within the renewable energy field.
Diagram 1 – Geothermal System Development Timeline (Source:www.oit.edu/news/2014/04/02/clean-energy-ribbon-cutting)
The campus has a long history of geothermal energy use, and with the technical help from different departments, the geothermal system has grown to allow better use of the energy.
Diagram 2 – Stakeholder Connection (Source: Lu & Tamara)
Oregon State Board of Higher Education: Originally awarded with $150,000 for use in exploration related to the selection of a new campus for Oregon Institute of Technology.
Department of Energy: • $4.5 million in grants
The American Recovery and Reinvestment Act: $1 million investment to develop an innovative technology that generates electricity from low-temperature geothermal resources
Energy Trust: contributed more than $2 mil to develop geothermal plant
Pacific Power: $250,000 Blue Sky grant. Excess clean energy generated will be donated to local low income area via an agreement with Pacific Power.
Oregon Higher Education Bond: $6 mil
Oregon University System: $2.4 Mil
Gene Culver, Geo-Heat Center: The study was carried out by him, a mechanical engineering technology faculty member and later one of the founders of the Geo-Heat Center, also the center provided great amount of data analysis and technology assistance during the development process. (iv)
Also, as the users of the system, including researchers, students and future investors or developers as well who would be benefited from the system are also important part of stakeholder network.
2. System Description
What is geothermal Energy?
The earth’s temperature varies upon location, however, regardless of the season or the degree of the outside temperature, the temperature of the earth a few feet underground remains constant throughout the year. Therefore, geothermal energy system takes the advantage of stable temperatures stored under the earth to balance building’s internal temperature relative to the exterior conditions via a series of buried pipes (either open or closed), wells, and heat ex-changers. By using geothermal energy can save 2/3 of the overall energy cost to heat and cool a structure.
Oregon Institute of Technology’s campus-wide geothermal energy system consists two major part of geothermal energy system, which are the geothermal power plant and mechanical heating system. (v) At soil depths greater than 30 feet below, Oregon Institute of Technology falls approximately along the 52 degree line.
Diagram 3 – Mean Earth Temperature (Source:www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm)
2.1 Geothermal Power Plant
Campus System Distribution
Diagram 4 – System Distribution(Source:greenpassivesolar.com/sustainable-renewable-energy/geothermal-energy/)
The geothermal processing plant located on southeast of the campus, and has approximately 12,000 sq. ft. operating space to process the geothermal energy that is extracted below the ground. The mechanical space for the geothermal energy system is fairly reasonable for the scale of the services space, which is more space efficient considering building construction.
1st Geothermal Power Plant System Quick FactsSource: Geo-Heat Center
System: 0.28 MW Geothermal Power Plant
Cost of Implementation: $890,000 project cost
Type of System: Binary Technology Geothermal System
Financial Savings: $23,000 each year
Energy Savings: 669,000 kilowatt hours
The system could reduce 250 tons of carbon dioxide, equal to removing 45 cars from the road for a year. (v)
2nd Geothermal Power Plant System Quick Facts
Source: Geo-Heat Center
SYSTEM: 1.75 mw Geothermal Binary Technology Power Plant
COST OF IMPLEMENTATION: $14,700,000 project cost
TYPE OF SYSTEM: Geothermal Energy System with Two turbines (1.0 MW and 0.75 MW)
ENERGY PRODUCED: 1 MW/yr(phase 1)
AREA SERVED: 602,300
UNITS SERVED: 11 Buildings heated, 5 buildings cooled, 2300 square feet of sidewalk
FINANCIAL SAVINGS: $400,000 each year
ENERGY SAVINGS: 7,646,000 kilowatt hours
This system’s reduction of carbon emission is equivalent to removing 545 Cars from the road for a year. (vi)
2.2 Energy Source
Diagram 5 – Geothermal Source (Source:greenpassivesolar.com/sustainable-renewable-energy/geothermal-energy/)
Klamath Falls has rich geothermal resource, by using the geothermal wells, 196°F water is pumped from 5,308 feet underneath the campus to extract the energy.
2.3 Power Plant Work Flow Diagram
Diagram 6 – Binary Cycle Power Demo (Source:greenpassivesolar.com/sustainable-renewable-energy/geothermal-energy/)
Oregon Institute of Technology has binary cycle power plants to produce certain amount of electricity to offset the utility cost. This power plant system operate on water at lower temperatures of about 225° to 360°F (107° to 182°C). The plants use the heat from the geothermal water to boil a working fluid, usually an organic compound with a low boiling point. The working fluid is vaporized in a heat exchange and used to turn a turbine. With the hot water, those turbines create electricity and spin in series—one after the other—to extract an optimal amount of energy from the system. After heat exchange, the water is then injected back into the ground to be reheated. The water and the working fluid are confined to separate closed loops during the whole process, so there are little or no air emissions at this energy production process.(vii)
2.2 Mechanical Heating System
Diagram 7 – Geothermal System Components (Source: Lu & Tamara)
A complete system typically includes the heat pump system and interior distribution system.
Also, the geothermal heat pump system itself consists of two primary components – a heat pump and a loop field. The heat pump is the unit that is placed inside the building, usually a separate mechanical room, and is responsible for the heat exchange. The loop field is the system of pipes that is laid underground. The system usually last for 50+ years. Loop field selection for the project varies based on the climate, the size of the building and location, but generally are responsible for about half of the total system installation cost. Loop fields can be installed horizontally or vertically. It is usually composed of a type of high density polyethylene pipe. (viii)
2.2.1 Loop Field System
Diagram 8 – Loop Field Types (Source: Lu & Tamara)
For the loop system. The loop is located outside the building, typically buried underground. The loop houses a liquid that absorbs the energy of the stable temperature that exists underground. A liquid, usually water or water blended with a refrigerant runs continuously through the entire length of the loop. (ix)
Most systems are closed loop system, which means, the same water & environmentally friendly antifreeze mixture is continually circulated throughout the loop field; the fluid never escapes. Additionally, to manage the environmental impact of geothermal energy use, closed loop is the only type of loop field allowed by some states as it reduces the possibility of water pollution.
An open loop field, sometimes called “pump & dump”, requires an ample source of groundwater. A well is drilled to the water source, it is pumped up the pipes to the heat pump where heat is extracted or injected and then sent down through a return well where it re-enters the water source. Open loops are not very uncommon since the system would require a significant water source below the surface.
2.2.2 Vertical Loop Field
Diagram 9 – Vertical Loop Field (Source: Lu & Tamara)
A vertical loop field is the most common installation process for a geothermal heat pump that is installed on limited spaces or to directly achieve the abundant geothermal energy underground. During a vertical loop field installation, a series of holes are drilled, the depth varies from hundreds to thousands feet deep, like the Oregon Institute of Technology’s geothermal system uses hot water from 5300’ deep underground. Then, piping is fed down these holes and connected in a loop pattern. All of the pipes are connected together outside of the structure, then connected into the buildings and attached to the heat pump units. (x)
2.2.3 Horizontal Loop Field
Diagram 10 – Horizontal Loop Field (Source: Lu & Tamara)
Also, horizontal loop fields are very common as well, however, the weakness is the installation usually occurs in more rural areas or yards with lots of space. A horizontal loop field installation requires a great deal of land because the installation need to dig up long trenches in order to lay the necessary amount of piping. In some cases, horizontal loop fields can be less costly to install than vertical because there is no drilling for wells like vertical loop fields.
2.2.4 Slinky Horizontal Loop Field
Diagram 11 – Slinky Horizontal Loop Field (Source: Lu & Tamara)
A pond loop field can be installed when the property is located near a large body of fresh water such as a pond or lake. Trenches, similar to horizontal loop field’s, are dug from the building to the body of water. These trenches are then filled with pipes which are connected to coils that are laid at the bottom of the lake or pond. These coils, often called Slinkys, utilize the temperature at the base of the lake or pond to heat and cool the home just like a horizontal or vertical loop field. (xi)
2.2.5 Interior Distribution System
Diagram 12 – Interior Distribution System (Source: Lu & Tamara)
For the interior distribution process, with the mechanical process of the heat ex-changers, the ventilation system distributes the treated air throughout the building. The distribution system is different to a forced air system that periodically disseminates blasts of air, a geothermal heating or cooling system is constantly pumping air throughout the building. (xii)
3. Possible Implications
The design and installation of geothermal systems are not doing it yourself projects and therefore require the services of a professional. In addition, the integration of geothermal exchange systems with other systems in a home requires special expertise.
Table 1- Cost (Source:greenpassivesolar.com/sustainable-renewable-energy/geothermal-energy)
Relies on electricity to power heat pump. Unless a backup electrical unit is installed the geothermal heating and cooling system will stop working if there is an electrical power failure.
Additionally, initial costs are high because of the cost of piping having to be installed in the ground, however, upkeep costs are low UNLESS a leak occurs in the loop. (xiii)
Source: Geo-Heat Center
The geothermal resource is renewable and clean, and saves energy cost for the users/developers, besides these, multiple uses of the energy could bring additional convenience, like snow melt system to prevent floor froze.
Besides the abundant geothermal resource under Klamath Falls, Oregon, the Geo-Heat Center on Oregon Institute of Technology campus provided resourceful engineer support for the geothermal system construction. Also, university wide renewable energy act and support from Department of Energy, also other community development partners, including American Recovery and reinvestment Act, Johnson Controls, Inc.,etc. provided additionally support for the completion for the project.
Sense of Installation Cost
Geothermal heating system price varies depending on the type of loop system, usually either vertical or horizontal. On average, a typical home of 2500 square feet, with a heating load of 60,000 BTU and a cooling load of 60,000 BTU will cost between $20,000 to $25,000 to install. This is around double the cost of a conventional heating, cooling, and hot water system, but geothermal heating/cooling systems can reduce utility bills by 40% to 60%.
The payback for a system can range from 2-10 years, while the lifetime of a system can be 18-23 years, almost double a conventional system. Additionally, renewable energy systems add value to the equity of your home. There are US tax rebates for energy efficiency improvements, including a 30% federal tax credit, and many state and utility companies offer incentives. (xiv)
i, Climate Region Guide, energy.gov/sites/prod/files/2015/10/f27/ba_climate_region_guide_7.3.pdf
ii, Dr. John W. Lund, PE, Emeritus Director, Geothermal District Heating, Oregon Institute of Technology, Klamath Falls, OR, energy.gov/sites/prod/files/2015/07/f24/10-District-Heating—J-Lund_0.pdf
iii, Links: http://www.oit.edu/news/2014/04/02/clean-energy-ribbon-cutting energytrust.org/library/case-studies/OIT_CS_1404.pdf energy.gov/eere/articles/oregon-institute-technology-recognized-increasing-its-use-geothermal-and-solar-energy
iv, John W. Lund and Tonya “Toni” Boyd, Geo-Heat Center OREGON INSTITUTE OF TECHNOLOGY GEOTHERMAL USES AND PROJECTS, PAST, PRESENT AND FUTURE, P1
vi, Oregon Institute of Technology Case Study, https://energytrust.org/library/case-studies/OIT_CS_1404.pdf
vii, energy.gov/eere/articles/oregon-institute-technology-recognized-increasing-its-use-geothermal-and-solar-energy http://www.oit.edu/sustainability/clean-energy energytrust.org/library/case-studies/OIT_CS_1404.pdf
ix, Geothermal Heat Pump Loop Fields, http://www.geothermalgenius.org/how-it-works/geothermal-ground-loop-fields
x, Geothermal Heat Pump Loop Field, http://www.geothermalgenius.org/how-it-works/geothermal-ground-loop-fields
xi, Geothermal Heat Pump Loop Field, http://www.geothermalgenius.org/how-it-works/geothermal-ground-loop-fields
xiv, Residential Geothermal Energy System Installation Cost Comparison, http://www.energyhomes.org/renewable%20technology/geoinstallation.html