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University of Texas at San Antonio
College of Engineering, San Antonio, Texas
ME-3293: Thermodynamics
Section Number: 002
Professor: Feng
Use of Geothermal Energy to Produce Hydrogen Thermodynamic
Analysis
TERM PAPER
Date of Submission: April 28, 2015
GRADE POINTS FOR THE REPORT:………………………………
Name
Signature
Grade points obtained
Douglas Sun
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Abstract:
Hydrogen production is one of many resources that could be used to generate power. Using
geothermal energy for hydrogen production is one of many ways to produce hydrogen, but could
be most beneficial due to many advantages. Four models are investigated for the use of geothermal
energy for hydrogen production. Case A shows the usage of geothermal work output as the work
input for an electrolysis process. Case B shows the usage part of geothermal heat to produce work
for electrolysis process and part of geothermal heat in an electrolysis process to preheat the water.
Case C explains using geothermal heat to preheat water in a high-temperature electrolysis process.
Lastly, case D demonstrates using part of geothermal work for electrolysis and the remaining part
for liquefaction. These models show the thermodynamic analysis for a reversible operation. The
effect of geothermal water temperature on the amount of hydrogen production per unit mass of
geothermal water is observed for all four cases with results compared. The results show that as
temperature of geothermal water increases the amount of production of hydrogen also increases. .
In case C, it shows that a great amount of hydrogen is produced in an ideal process at 200°C
compared to case A and B for the same geothermal resource, as case C shows 1.911 g of hydrogen
produced using 1 kg of geothermal water in the high-temperature electrolysis compared to 1.34
and 1.42 g of hydrogen produced using 1 kg of geothermal water in the high-temperature
electrolysis from case A and B respectively. While case D allows both hydrogen production and
liquefaction using the same geothermal resource, and provides a good solution for the remote
geothermal resources.
Keywords:
Hydrogen Production Geothermal Energy Electrolysis
Ideal (reversible) operation Binary Cycle Precooled Linde-Hampson cycle
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TABLE OF CONTENTS
Section Page
Abstract ii
1. Introduction ……………………………………………………………… 1
2. Background …………………………………………………………………… 2
3. Methodology and Analysis ……………………………………………………… 3
4. Results and Discussion ………………………………………………………… 5
5. Conclusions…………… ……………….…………………………………. 6
6. References ………..…………………………………….………………… 8
Appendix ………………………………………………………………….. A
1 Introduction
Geothermal energy is one of the oldest sources of energy, while it is simply reusable energy that
comes from the heat inside of the Earth. This heat from inside the Earth is produced by a
combination of two different sources. The first original heat that is produced comes from the
formation of the Earth by gravitational collapse, which is the process by which stars and galaxies
form from interstellar gas under the influence of gravity. The second source of production of heat
is by the radioactive decay of isotopes. Geothermal energy is a renewable source of energy that
present many advantages as it does not depend on the climatic conditions, nor the different seasons
or the time of the day. While needing the geothermal resources are key to the production of
geothermal energy. The geothermal energy is produced to provide heat that will be turned into
work that can later be produced into electricity.
The production the geothermal energy is not something that can be obtained so simply. Finding
the right resources for the production of geothermal energy is key. Geothermal resources are the
key to providing the production of geothermal energy, but there are only a limited amount of places
that will carry the geothermal resources that workers may obtain. Geologists use many methods
to find geothermal resources. They may study aerial photographs and geological maps. They may
analyze the chemistry of local water sources and the concentration of metals in the soil. They may
measure variations in gravity and magnetic fields. Yet the only way they can be sure there is a
geothermal resource is by drilling wells to measure underground temperatures. Some visible
features of geothermal energy are volcanoes, hot springs, geysers, and fumaroles. But you cannot
see most geothermal energy. The most active geothermal resources are usually found along major
