Abstract
The scope of this study are the development of an integrated simulation model for the estimation of the energy output of a deep Closed Loop Geothermal System (CLGS) and the discussion of several approaches to the enhancement of this output. Due to its closed character this kind of geothermal installation provides the opportunity of heat utilization even in dry and impermeable geological zones without any stimulation effort and the usage of external fluids. After a short introduction of the system itself and the limitations of other geothermal systems that are available, the investigations start with the description of the state-of-the-art with regard to the energy output analyses of the CLGS that have been done in the past. These are evaluated and their shortcomings are identified. The newly developed and introduced 3-dimensional approach of this study is a capable tool for the pre-feasibility phase of the project development of a CLGS. A geological/geothermal model summarizes selected relevant data and information about the project area in the form of a spatial data distribution. Thereby the formation boundaries are modelled as well as local in-homogeneities. The lithology can be modelled as well as the distribution of the thermal and physical properties of the
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Citation Formats
Schulz, Sven-Uwe.
Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS).
Germany: N. p.,
2008.
Web.
Schulz, Sven-Uwe.
Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS).
Germany.
Schulz, Sven-Uwe.
2008.
"Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS)."
Germany.
@misc{etde_21240869,
title = {Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS)}
author = {Schulz, Sven-Uwe}
abstractNote = {The scope of this study are the development of an integrated simulation model for the estimation of the energy output of a deep Closed Loop Geothermal System (CLGS) and the discussion of several approaches to the enhancement of this output. Due to its closed character this kind of geothermal installation provides the opportunity of heat utilization even in dry and impermeable geological zones without any stimulation effort and the usage of external fluids. After a short introduction of the system itself and the limitations of other geothermal systems that are available, the investigations start with the description of the state-of-the-art with regard to the energy output analyses of the CLGS that have been done in the past. These are evaluated and their shortcomings are identified. The newly developed and introduced 3-dimensional approach of this study is a capable tool for the pre-feasibility phase of the project development of a CLGS. A geological/geothermal model summarizes selected relevant data and information about the project area in the form of a spatial data distribution. Thereby the formation boundaries are modelled as well as local in-homogeneities. The lithology can be modelled as well as the distribution of the thermal and physical properties of the rocks. The temperature distribution can be modelled using map or drill log data and be interpolated using geostatistical methods. After the combination of the geological/geothermal model and the technical model of the CLGS containing all relevant data with regard to the drill hole design, dimensions, casings and thermal properties of the installed materials, incl. the annuli, the thermal behaviour of the heat bearing fluid (HBF) flowing within the pipe system is simulated over time in connection with the simulation of the thermal behaviour of the surrounding rock mass. This core simulation is added by the afterwards processed scenario based energy supply simulation that calculates the amounts of energy (electricity, heat or combined heat and power (CHP)) that can be supplied to the grids. This goes along with the simultaneously calculation of the achievable incomes that are related to the expenses in the form of static annual cash flows. After the theoretical introduction and derivation of the model a set of examples is processed that proves the functionality of the model on the one hand and shows the energy utilization potential of the CLGS technology on the other hand. The examples are divided into a set of general examples under ideal conditions that are adequate to demonstrate the model behaviour. Secondly an assumed example that is not reality but based on real geological and technical data is processed and evaluated. The second part of these investigations discusses possible steps and optimization approaches for the improvement of the calculated energy output. The discussion of the risks with regard to the system in comparison to enhanced geothermal systems (EGS) as well as to other types of renewable energy systems shows the state of the CLGS. An evaluation and plausibility discussion of the model finalizes the investigations leading to the derivation of the limits of this technology. (orig.)}
place = {Germany}
year = {2008}
month = {Aug}
}
title = {Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS)}
author = {Schulz, Sven-Uwe}
abstractNote = {The scope of this study are the development of an integrated simulation model for the estimation of the energy output of a deep Closed Loop Geothermal System (CLGS) and the discussion of several approaches to the enhancement of this output. Due to its closed character this kind of geothermal installation provides the opportunity of heat utilization even in dry and impermeable geological zones without any stimulation effort and the usage of external fluids. After a short introduction of the system itself and the limitations of other geothermal systems that are available, the investigations start with the description of the state-of-the-art with regard to the energy output analyses of the CLGS that have been done in the past. These are evaluated and their shortcomings are identified. The newly developed and introduced 3-dimensional approach of this study is a capable tool for the pre-feasibility phase of the project development of a CLGS. A geological/geothermal model summarizes selected relevant data and information about the project area in the form of a spatial data distribution. Thereby the formation boundaries are modelled as well as local in-homogeneities. The lithology can be modelled as well as the distribution of the thermal and physical properties of the rocks. The temperature distribution can be modelled using map or drill log data and be interpolated using geostatistical methods. After the combination of the geological/geothermal model and the technical model of the CLGS containing all relevant data with regard to the drill hole design, dimensions, casings and thermal properties of the installed materials, incl. the annuli, the thermal behaviour of the heat bearing fluid (HBF) flowing within the pipe system is simulated over time in connection with the simulation of the thermal behaviour of the surrounding rock mass. This core simulation is added by the afterwards processed scenario based energy supply simulation that calculates the amounts of energy (electricity, heat or combined heat and power (CHP)) that can be supplied to the grids. This goes along with the simultaneously calculation of the achievable incomes that are related to the expenses in the form of static annual cash flows. After the theoretical introduction and derivation of the model a set of examples is processed that proves the functionality of the model on the one hand and shows the energy utilization potential of the CLGS technology on the other hand. The examples are divided into a set of general examples under ideal conditions that are adequate to demonstrate the model behaviour. Secondly an assumed example that is not reality but based on real geological and technical data is processed and evaluated. The second part of these investigations discusses possible steps and optimization approaches for the improvement of the calculated energy output. The discussion of the risks with regard to the system in comparison to enhanced geothermal systems (EGS) as well as to other types of renewable energy systems shows the state of the CLGS. An evaluation and plausibility discussion of the model finalizes the investigations leading to the derivation of the limits of this technology. (orig.)}
place = {Germany}
year = {2008}
month = {Aug}
}