Teaching Geothermal Energy in an Undergraduate Renewable Energy
Engineering Program
Toni Boyd,
Senior Engineer, Geo-Heat Centre, Oregon Institute of Technology
Andrew Chiasson,
Program Manager, Geo-Heat Centre, Oregon Institute of Technology
Jamie Zipay,
Professor, REE Program Director, EERE Department, Oregon Institute of Technology
ABSTRACT
The Renewable Energy Engineering (REE) program launched at Oregon Institute of Technology
(OIT) in 2005 is the first ABET accredited program in renewable energy engineering in the US.
The main objectives of the program were to provide graduates for careers as professionals in
energy engineering and focus on renewable energy disciplines. One of these disciplines is
geothermal energy. Geothermal energy usage has been a focus of the OIT campus in Klamath
Falls through the Geo-Heat Centre for research, campus heating with a direct use system and
most recently a low temperature geothermal power plant. With the presence of various campus
resources in geothermal it is only natural to add this focus to the REE program with a course
sequence in Geothermal Energy Engineering and Applications.
This paper presents the design, development and evaluation of an undergraduate course sequence
with a focus on the energy source and applications such as direct use heating, geothermal heat
pumps and geothermal electrical power production. Originally the REE program had a single
course that was more of a survey on geothermal energy but the program students were requesting
a stronger focus in this area of renewable energy. This led to the development of a three term
senior sequence that is presented in this paper.
One of the main objectives is to provide an engineering and science foundation with regards to
geothermal energy. This includes areas such as geothermal heat sources, reservoir geology, and
thermodynamics of the energy conversion processes. Another objective area is the site
exploration, drilling, and evaluation of energy extraction capability. This area also provides
background for analyzing environmental and economic impacts of such energy solutions. The
focus is kept on the engineering design and analysis of geothermal energy resources. These
objectives are met in the first course in the sequence.
Another main objective is applying the science by way of actual applications converting
geothermal energy. These objectives are met mostly in the two remaining courses in the
sequence on Geothermal Heat Pumps and Geothermal Electrical Power Generation. The Direct
Use Heating System (HVAC) application is presented in the first course. The focus is on design,
development, impacts and efficiency of the conversion processes in the sequence. Students in the
program have expressed a great deal of interest in this approach. This is evidenced by an increase
in student involvement in geothermal resources on campus through special project classes,
design competitions and senior capstone projects. Some of the program graduates have also been
considering continuing educational opportunities in geothermal energy.
INTRODUCTION
Geothermal Energy
The energy situation facing the world today has brought about an increased interest in better
utilization of renewable energy sources for solving problems in heating and cooling, electrical
power generation and transportation. Much of the current focus has been on renewable
generation sources such as solar, wind, hydroelectric, solar thermal, bio-fuels and bio-gas, and
others. Many of these sources require an energy storage system due to the intermittent nature of
the source such as solar or wind. One source that does not have this requirement is geothermal
energy, it is not intermittent and as long as the geothermal fluid flows energy is available for
conversion and usage. Currently geothermal energy provides a small percentage of renewable
energy utilization worldwide [3] due to the geographic limits of geothermal as illustrated in
Table 1. Geothermal Energy represents 2.8% of the total production of electricity in the US and
4% of the gross production of electricity. When compared to other renewable sources for
electrical power generation the percentage for geothermal increases to 8.3% for capacity and
10.7% of total production. In the US geothermal energy distribution is concentrated on the west
coast [3] as illustrated in Figure 1 a US Geothermal Resource map and the overall percentage
usage has increased in the western US over the last decade. This demonstrates the significance of
geothermal energy on the west coast for production of electricity. In the geothermal course
sequence a course in geothermal power plants was determined to be essential.
Ref. www.eia.doe.gov [3]
Figure 1 Geothermal Resource Distribution Map [3]
Geothermal energy has the capability of being utilized for heating and cooling as well as
generating electricity from geothermal power plants with the main constraint being the
temperature of the geo-fluid. As illustrated in the resource map in Figure 1 the blue shaded areas
are best suited for heating and cooling and other applications called direct use [2] while the red
areas are better suited for power plants. Direct use was added as the application focus in the first
course of the sequence.
Geothermal heat pumps can also be used for heating and cooling without the requirement of a
geothermal resource present (the white areas of map) such as for direct use or power plants. The
main constraints on developing geothermal heat pumps are economic and environmental. The
costs can elevate in colder climates due to increased depth of the piping and development of the
heat pump footprint. This information was integral in the decision to have the second course
focus on geothermal heat pumps. As the energy costs continue to rise there is an increase in
demand for heating and cooling systems based on geothermal heat pumps and a need for
engineers with backgrounds in these areas to develop these systems.
Part of the interest in a geothermal course sequence was the increased presence of geothermal
energy usage on the OIT campus. The OIT campus has had a geothermal direct use heating
system in place since the late 1960’s. Currently all campus heating is geothermal and the cooling
is from electrical chillers. This energy resource is provide by three production wells with a
temperature of 192 ºF and flow rate of 980 gpm in the southeast corner of the campus. These
resources led to the establishment of the Geo-Heat Centre at OIT a centre of excellence that
provides engineering support for geothermal on campus, geothermal research and geothermal
resource development in the western US region. Most recently the campus has added a small
scale low enthalpy power plant on campus (binary cycle) that generates 280 kW (installed
capacity) of electrical power using the production wells, it is the first combined heat and power
production plant in Oregon. The most recent project was the drilling of a 5300 foot deep well to
provide a geothermal fluid for a larger power plant (1.75 MW installed capacity) that is in the
development phase. With this strong presence of geothermal energy production and “working”
labs it makes sense to add a strong course sequence in geothermal energy for the REE program.
Renewable Energy Engineering in Education
Many of today’s students entering college are well aware of the energy issues that face both the
US and the world. These students want to help solve these problems by choosing careers
involved in energy especially renewable or alternative energy and are looking for college degrees
and programs that focus in these areas. Although the area of renewable energy has a strong
presence in graduate engineering programs it has been somewhat absent in undergraduate
engineering. There are some two year technical programs that focus on installation and site
support and some graduate programs that focus on research and development areas in renewable
energy. But at the undergraduate level renewable energy engineering has been limited to some
EE or ME programs offering a course or a track of two to four courses in renewable energy or
electrical power systems but few focused BS degrees in renewable energy engineering.
The Renewable Energy Program began in 2005 as a Renewable Energy Systems program with a
focus on science and technology of renewable energy systems (RES). In 2007 the program was
redesigned as a Renewable Energy Engineering (REE) program after consulting with the RES
industrial advisory board (IAB). The IAB suggestion was to provide a BS in Renewable Energy
Engineering that would allow graduates to take a FE exam for PE licensure and still maintain the
original program focus of applied engineering and systems engineering. The program team also
saw an increased need for undergraduate RE engineers in areas such as applications, test, site
analysis and selection as well as research and development support. The program is a blend of
electrical, mechanical and civil engineering with a core focus of courses such as AC/DC Circuit
Analysis, Electronic Devices, Solid State Devices, Control Systems, Statics, Thermodynamics,
Heat Transfer, Fluid Mechanics and Programming. The main program goal is to provide
graduates for careers in energy engineering with an emphasis on renewable energy integration
and systems. This goal is accomplished through the RE core classes with required classes such as
PV Systems, Fuel Cells and more, electives such as Solar Thermal, Bio-Fuels and Bio-Mass,
Geothermal and more and a Senior Capstone Project.
A Senior Sequence (three courses) was recently added to the program to provide a specialized
course in system design in target areas of renewable energy such as Power Systems, Energy
Storage, Green Building Design and Geothermal Systems. This sequence is intended to insure
that the four areas of renewable energy are covered with an emphasis on system design:
1. Generation: Generation of energy from the renewable source.
2. Storage/Conversion: Storing or converting the renewable energy to a usable form.
3. Integration/Design: The integration of the energy to the existing grid or building
envelop for use.
4. Use/Applications: End usage of energy for heating/cooling, transportation or electrical
power.
The focus of this paper is on the Geothermal System sequence that was implemented in the
2011-12 academic year and is also offered again in this academic year. Not all sequences are
offered every year due to resources and student interest.
GEOTHERMAL COURSE SEQUENCE
Initially the REE program had a single course in Geothermal Energy and Applications that
intended to cover the basics of geothermal energy production and site analysis and development
with an emphasis on the engineering. This course also presented an overview of various
geothermal energy uses and applications such as direct use, geothermal heat pumps and
geothermal power plants. This course had a prerequisite of thermodynamics, heat transfer and
fluid dynamics to establish a good engineering foundation and background for topics in the
course. To try to cover all the material in a single ten week course (quarter system) required that
the applications be presented with breadth but not much depth. Feedback from students
suggested that this was not adequate and more engineering and design depth was needed.
This led to the development of the current three term senior sequence course that is the topic of
this paper. The sequence continues the focus on systems engineering and not a strong focus on
the geology or sustainability of geothermal systems. The first course is a course in general
geothermal energy and is very similar to the original single course. The second course covers
geothermal heat pumps and the third course covers geothermal power plants. This sequence
expands the coverage of geothermal uses and applications with a focus on the engineering design
of such systems. The prerequisites still remain the same to provide the basic engineering
foundation in thermodynamics, heat transfer and fluids. Details on the three courses are provided
in the following sections.
First Course: Geothermal Energy and Direct Use
The first course covers the three main areas of geothermal energy and heat resources, basic
applications (focus on direct use) and economic and environmental impacts of using geothermal
energy as detailed in the following table below. The first portion of the course introduces the
geothermal heat resource and geologic features associated with it to provide an understanding of
the benefits and constraints of the resource. Site exploration is covered for an understanding of
how a site is selected for energy conversion with an emphasis on the engineering and data
acquisition such as using geo-thermometers, seismic, resistivity and gravity surveys. Another
area covered is the site preparation for drilling and heat extraction with a focus on drilling
technology, platforms and environmental and economic impacts.
WEEK
1
2
3
4
5
6
7
8
9
10
11
TOPICS
Course Introduction, Thermodynamics Review, Geothermal Heat Generation
Basic Applications (power generation, direct use, heat pumps), Geology, Tectonics
Site Exploration(geological, geochemical, geophysical, surface)
Test and Site Drilling, Platforms, Operation
Energy Economics and Environmental Impacts
Geothermal Resource Reservoir (basic models, requirement)
Direct Use (heating/cooling, aquaculture, agriculture, industrial)
Basic Systems (thermodynamic models, losses, piping, heat transfer)
HVAC System Designs and Equipment, Geothermal Fluid Temperature Requirements
Equipment (pumps, piping, heat exchangers, selection)
Final Exam, Research Paper and/or Final Direct Use Project
The final portion presents an in depth look at direct use applications (shown in Table 2 on Direct
Use in the US [3]) with a focus on heating and cooling (HVAC designs). System models and
temperature requirements [2] are used to design basic systems using principles of heat transfer
and losses. Basic HVAC equipment is covered such as pumps, piping, heat exchangers, chillers
through system design and case studies. The other geothermal applications such as power plants
and heat pumps are covered but not at much depth. This provides a good look at geothermal
energy for the students just taking a single elective course in geothermal (not the whole
sequence) with a focus on direct use space/district heating applications. The main heat exchanger
for the OIT heating system is shown in Figure 2 below.
Table 2 Direct Use Applications in the US [3]
Use
Installed
Capacity
Annual Energy Use
Capacity Factor
(TJ/yr = 1012 J/yr)
(MWt)
Individual Space
Heating
District Heating
139.89
1,360.6
0.31
75.10
773.2
0.33
Air Conditioning
(Cooling)*
Greenhouse Heating
2.31
47.6
0.50
96.91
799.8
0.26
Fish Farming
141.95
3,074.0
0.69
Agricultural Drying **
22.41
292.0
0.41
Industrial Process
Heat ***
Snow
Melting
17.43
227.1
0.41
2.53
20.0
0.25
Bathing and
Swimming
Subtotal ****
112.93
2,557.5
0.72
611.46
9,151.8
0.48
12,000.00
47,400
0.13
12,611.46
56,551.8
0.12
Geothermal Heat
Pumps
Total
* Other than heat pumps; ** Includes drying or dehydration of grains, fruits
Figure 3. Plate Heat Exchanger in the OIT College Union [3]
Second Course: Geothermal Heat Pumps
The second course in the sequence presents a strong engineering design focus on geothermal heat
pump applications. This course covers a topic of geothermal heating that is not as restricted to
certain geographic areas and is increasing in usage in the US [4]. In this course heat pump
fundamentals and operation is covered initially to develop a background in basic heat pumps
with an emphasis on the thermodynamic cycles as shown in Figure 4. System operation, design
and equipment selection is covered for different applications and uses (both residential and
commercial). The prerequisite for this course is still thermodynamics, heat transfer and fluids
and not the first sequence course (it would be helpful though). This allows this course to be used
as a single elective for REE program students in heat pumps. The basic principles of geothermal
energy from the first course are not required here so the course focus is on geothermal (ground
source) heat pumps. After the basics of heat pump operation and design are covered the course
presents coverage of the design and operation of traditional heat exchangers, down-hole heat
exchangers (vertical and horizontal). Another area covered is HVAC building design using
geothermal heat pumps with a focus on equipment, piping, pumps and heat exchangers. The
main portion of the course covers the different types of heat pump systems with regards to
design, operation, efficiency and impacts.
Figure 4 Heat Pump Operating in Heating Cycle [4]
The detail of course topics are given in the following table.
WEEK TOPICS
1
Course Overview, Heat Pump Fundamentals
2
Heat Pump Fundamentals/Operation, Heat Pump Air Ventilator
3
Select Heat Pumps, Requirements, Ground Coupling
4
Closed Loop Vertical, Single Borehole Heat Exchanger (HEX)
5
Design Multi-Borehole HEX
6
Closed Loop Horizontal HEX, Earth Tubes
7
Surface Water Heat Pump Systems
8
Building Designs: Piping, Pumps, Hydronics
9
Open Loop Groundwater Heat Pump Systems
10
Project Design/Presentations
11
Final Project
As in the first course the pedagogy is on system design and application with a final design
project using heat pumps for heating a building.
Third Course: Geothermal Power Plants
The final course in the senior sequence is about using geothermal energy to generate electrical
power. The course begins with a background in geothermal power plants covering development,
US/World distribution, basic types of plants and comparison to other traditional power plants [1].
The next section covers reservoir physics and simulation models for the geothermal resource.
The coverage here is expanded from the first course to add mathematical models to the physical
model presented in the earlier course as well as flashing, drawdown pressure, fluid flow and
mass flow measurements and model adjustments.
The next area of the course covers the main types of power plants with a focus on energy
conversion, thermodynamics, PH (Pressure/Enthalpy) and SH (Entropy/Enthalpy) models and
diagrams in the engineering design and operation. Each plant type has a section on operation,
equipment, layout, efficiency/losses and economic and environmental impacts. The main
traditional high enthalpy plants such as dry steam, single flash and double flash are covered first
[1] before moving on to low enthalpy power plants using a closed loop binary cycle (Figure 5, 6,
7). Binary cycle power plants are being utilized more and the course devotes more time to this
type [5]. For this type coverage is added for the basic binary cycles (Organic Rankine and
Kalina) and basic refrigerant selection. The course topic details are given in the following table:
WEEK
1
2
3
4
5
6
7
8
9
10
11
TOPIC
Course Overview, Geothermal Energy Review
Geothermal Reservoir, Physical Models
Reservoir Pressure Models, Drawdown Pressure, Flashing
Dry Steam Power Plants (operation, conversion and design)
Single Flash/Double Flash Power Plants (operation, conversion and design)
Single Flash/Double Flash Power Plants (equipment, design, impacts)
Binary Cycle Power Plants (Rankine/Kalina Cycles, operation and conversion)
Binary Cycle Power Plants (equipment, design, closed loop, impacts)
Binary Cycle Power Plants (case studies, project)
Enhanced Geothermal Systems. Hybrid Systems
Final Exam, Project, Research Paper
As in the first course the pedagogy is on system design and application with a final design
project using case studies of regions for different types of power plants and a research paper.
Students are also given the project opportunity using a study of the small scale binary power
plant on campus.
FIGURE 5. Binary Cycle Power Plant at the OIT Campus [3]
Figure 6 Binary Cycle Power Plant Building and Cooling Tower [3]
Figure 7 Binary Cycle Power Plant Block Diagram [5]
Other Activities
Students have been involved in other courses, project and internships in areas related to
geothermal energy. Many students have found part-time employment through the OIT campus
Geo-Heat Centre working on the research data bases in the centre. Recently an elective course
was offered for a group of students that competed in the National Renewable Energy Lab
(NREL) geothermal site analysis competition for the Rio-Grande Rift zone in southern New
Mexico. Another class was offered to students to develop a Geothermal HVAC System retrofit
for a school district in Northern California. Some recent student projects include a senior project
on design and test of a new type down-hole heat exchanger and a class project on the feasibility
of solar thermal enhanced geo-fluids in power generation. The combination of the geothermal
senior sequence, various geothermal class projects and special topic classes provide a strong
program focus on geothermal energy for this new and unique program.
RESULTS and CONCLUSIONS
Course Outcomes
The addition of this course sequence to the REE program has added an increase in design focus
(program outcome C – System Design) and engineering problem solving (program outcome E)
in the area of thermodynamics, heat transfer and fluid flow in a renewable energy system such as
geothermal. This was accomplished with the increase in depth provided by the sequence over
just breadth that was provided by the single course in geothermal systems. This sequence also
provided a better system look at environmental and economic impacts of engineering solutions
(program outcome H). This area is a strong focus in the course comparing geothermal
environmental pollution and costs to traditional power generation systems and HVAC systems.
The strong project focus of the course sequence allows the students to use HVAC analysis tools
and data acquisition systems (program outcome K) in an engineering environment. The course
sequence is currently being used in the program assessment plan for outcomes H and K with
more planned for the future.
Students
The biggest impact of this course sequence has been observed in program students in course
enrollments, student projects and internship opportunities. The course sequence was offered in
academic year 2011-12 and currently in 2012-13. It currently has the highest enrollment with
most planning on taking the full sequence (some students take one or two courses as electives.
Student interest in geothermal projects has also increased with some special project courses such
as a Geothermal HVAC project class that had three student teams working on developing
proposals for a Geothermal HVAC retrofit of an older gas fired boiler system. The course had
twenty students enroll for this project (we expected 10). A student project team participated in a
NREL regional geothermal site assessment and placed well in the competition and received an
invitation to a poster session at the annual GRC meeting. The course sequence is taught by REE
program faculty and Geo-Heat Centre senior engineers that has introduced the students to the
Geo-Heat Centre and has provided opportunities for internships in areas of geothermal energy
and research. Students have been working internships in areas such as research databases, well
testing, power plant support and geothermal heat pump surveys through the Geo-Heat Centre and
other regional summer internships.
Future
The REE program is currently launching an MSREE program and the plan is to offer a track on
Geothermal Energy that can be cross-listed with the undergraduate course sequence. Students
will be able to use this sequence to build a foundation for on campus graduate level research and
projects in geothermal energy systems. There is currently an undergraduate research project
pending through an NSF grant to fund undergraduate research in geothermal power plant
modeling and simulation and enhancing power production using a concentrated PV hybrid type
of system. This project will fund a team of 8-10 students for a long term research project over a
three year time frame. There is also interest from an engineering consulting firm to partner with
OIT on the research part of the plant enhancement. Students in the course sequence will be
given top priority for consideration and many have already expressed interest in the pending
project. The relationship between the REE program and the Geo-Heat Centre will continue to
grow and provide more unique opportunities in geothermal energy education for the REE
stsudents.
REFERENCES:
[1] DiPippo, Ronald; “Geothermal Power Plants”, Butterworth-Heinemann, 2nd Edition 2008
[2] Glassley, William; “Geothermal Energy: Renewable Energy and the Environment” , CRC Press, 2010
[3] Lund, John; Boyd, Tonya; Gawell, Karl; and Jennejohn, Dan; “The United States of America Country Update
2010” Geo-Heat Quarterly Bulletin 29/1 Oregon Institute of Technology, Klamath Falls, OR 2010.
[4] Lund, John; Sanner, B; Rybach, L; Curtis, R; and Helstrom, G.; “Geothermal (Ground Source) Heat Pumps – A
World Overview” Geo-Heat Quarterly Bulletin 25/3 Oregon Institute of Technology, Klamath Falls, OR.
[5] DiPippo, Ronald; “Small Geothermal Power Plants: Design, Performance and Economics” Geo-Heat Quarterly
Bulletin 20/2 Oregon Institute of Technology, Klamath Falls, OR.