Desarrollo de nuevas líneas de investigación en el campo del diseño y aprovechamiento de sistemas geotérmicos

Tesis por compendio de publicaciones[ES] Es universalmente aceptado que se necesita urgentemente una transición energética global para cumplir los objetivos de limitar el aumento medio de la temperatura superficial global por debajo de 2°C. Con el objetivo de reducir las emisiones de dióxido de carbono (CO2), las soluciones bajas en carbono como los recursos renovables jugarán un papel fundamental. La transición energética requerirá una fuerte innovación tecnológica, especialmente en el campo de las energías renovables. En este sentido, los recursos geotérmicos están recibiendo un interés creciente derivado de su naturaleza de confiabilidad, sustentabilidad, abundancia y menor impacto en el medio ambiente. La gran cantidad de ventajas que definen a esta fuente renovable hace que esta energía sea considerada como uno de los recursos potenciales futuros para satisfacer la creciente demanda energética mundial. Dependiendo de la naturaleza y las condiciones del recurso, la energía geotérmica permite su uso para generar electricidad, así como para fines de calefacción/refrigeración. La presente Tesis Doctoral se centra en el análisis del recurso geotérmico global, incluyendo la caracterización térmica del suelo en ambientes someros y profundos, la evaluación del sistema de bomba de calor y la mejora del diseño geotérmico somero general. De esta forma, el principal objetivo del trabajo de investigación de esta Tesis es contribuir a un uso más extenso de esta energía renovable. Con este objetivo, las líneas de investigación incluyen un extenso trabajo de campo y pruebas de laboratorio, procesamiento experimental y de simulación y diferentes tareas informáticas. Desde la identificación inicial de las principales debilidades asociadas al uso generalizado de recursos geotérmicos, los esfuerzos se han enfocado en la realización de una serie de pruebas de laboratorio y trabajo de campo. Posteriormente, los trabajos experimentales han sido complementados con la implementación de herramientas informáticas y software específico que han permitido completar los estudios prácticos y teóricos. Se espera que las conclusiones obtenidas de la investigación presentada en esta Tesis contribuyan al desarrollo geotérmico futuro más óptimo. En resumen, la presente Tesis Doctoral contiene información valiosa, recopilada en diferentes trabajos científicos, que incluyen todo el saber hacer y la experiencia adquirida durante la etapa de investigación.[EN] It is universally accepted that a global energy transition is urgently needed to meet the objectives of limiting average global surface temperature increase below 2°C. With the aim of reducing the carbon dioxide (CO2) emissions, low-carbon solutions such as the renewable resources will play an essential role. The energy transition will be enabled by technological innovation, especially in the field of renewable energy. In this sense, geothermal resources are getting a growing interest derived from their nature of reliability, sustainability, abundant resource and minor impact on environment. The large number of advantages that define this renewable source makes this energy considered as one of the future potential resources to meet the world's growing energy demand. Depending on the nature and conditions of the resource, geothermal energy allows to be used for the generation of electricity as well as for heating/cooling purposes. The present Doctoral Thesis is focused on the analysis of the global geothermal resource, including the ground thermal characterization in shallow and deep environments, the evaluation of the heat pump system and the improvement of the general shallow geothermal design. In this way, the principal objective of the research work of this Thesis is contributing to a more extensive use of this renewable energy. With this aim, research lines include extensive field work and laboratory tests, experimental and simulation processing and different computing tasks. From the initial identification of the main weaknesses associated to the general use of geothermal resources, efforts were focused on the performance of a series of laboratory tests and field work. Experimental works was then complemented with the implementation of computing tools and specific software that allowed completing the practical and theoretical studies. Conclusions obtained from the research presented in this Thesis are expected to contribute to the most optimal future geothermal development. In summary, the present Doctoral Thesis contains valuable information, compiled in different scientific works, which include all the know-how and expertise arsing during the research stage

¿Qué Método Utilizar Para Estimar la Temperatura estática de una formación de Petróleo?

Conocer la temperatura estática de una formación de petróleo es importante a la hora de evaluar y terminar un pozo. Existe una gran variedad de métodos para la determinación de esta temperatura. Cada método utiliza hipótesis y simplificaciones distintas que llevan a estimaciones diferentes, en algunos casos bastante alejadas del valor real. Esto hace difícil saber qué método utilizar. En este trabajo, se aplican los métodos de cálculo más comunes - Horner (HM), flujo radial y esférico (SRM), de las dos medidas (TLM) y de fuente de calor cilíndrica (CSM)- a cuatro pozos distintos. Se describe cómo aplicarlos en casos reales. Se presta especial atención a establecer los datos necesarios en cada caso: propiedades termo-físicas y número de medidas, y se proporcionan criterios para estimarlos en caso de no conocer su valor real. Como conclusiones a este trabajo se presentan una serie de pautas que permiten seleccionar el método de cálculo más conveniente en función de la información de que se dispong

The peruvian criminal and penitentiary system: Political-criminal reflections

En este artículo se reflexiona sobre el contenido del Derecho penal peruano a la luz de la realidad política del país tras el régimen de Alberto Fujimori; se describe la situación de su sistema penitenciario y se señalan los problemas más críticos en esta materia. Se plantea la necesidad de abordar la reforma del marco normativo y del sistema penitenciario, a partir de una serie de propuestas que contemplen el principio de proporcionalidad y la resocialización.This article considera the nature of Peruvian Criminal Law given the political realities of the country in the aftermath of the regime of Alberto Fujimori; it describes the situation of the penal system highlighting the most critica] problems of the country in this area. It poses the need to undertake reform of the normative framework and of the penal system, starting from a series of proposals which incorporate principies of proportionality and of resocialization

Assessment of the geothermal potential in the region of Ávila (Spain): An integrated and interactive thermal approach

Exploring and exploiting a geothermal resource has become one of the most prolific tasks for contributing to the global sustainable development. Despite this fact, several countries, such as Spain, are still far from achieving a generalized use of these renewable systems. The reason for this underuse often derives from the lack of information and characterization of the geothermal energy source. Considering this, the present research aims to provide relevant data about the geothermal potential of the Spanish region of Ávila. The geological context of this province lays the foundations for considering the region as a promising site for different geothermal uses. In order to estimate the geothermal energy potential of the region, the existing geological information has been complemented with thermal surveys carried out in the study area. The experimental measuring has consisted of the register of the underground temperature in piezometers of variable depth and natural springs distributed throughout the province. The processing of these records has allowed knowing the thermal evolution of the subsoil at the different levels evaluated in the research. Results show that there are two main potential areas in the province that could be successfully used for heating purposes (maybe as part of district heating systems) and for future deeper evaluations in the sense of Hot Dry Rock (HDR) techniques. Final conclusions have also been included in an interactive and open-source tool that allows visualizing the thermal findings with the aim of planning future geothermal uses in the region

Geophysical Prospecting for Geothermal Resources in the South of the Duero Basin (Spain)

[EN]The geothermal resources in Spain have been a source of deep research in recent years and are, in general, well-defined. However, there are some areas where the records from the National Institute for Geology and Mining show thermal activity from different sources despite no geothermal resources being registered there. This is the case of the area in the south of the Duero basin where this research was carried out. Seizing the opportunity of a deep borehole being drilled in the location, some geophysical resources were used to gather information about the geothermal properties of the area. The employed geophysical methods were time-domain electromagnetics (TDEM) and borehole logging; the first provided information about the depth of the bedrock and the general geological structure, whereas the second one gave more detail on the geological composition of the different layers and a temperature record across the whole sounding. The results allowed us to establish the geothermal gradient of the area and to discern the depth of the bedrock. Using the first 200 m of the borehole logging, the thermal conductivity of the ground for shallow geothermal systems was estimated

Geophysical exploration for shallow geothermal applications: A case study in Artà, (Balearic Islands, Spain)

[EN] Within the installation of a shallow geothermal system, the lack of information on the subsoil frequently leads to errors in the design of the geothermal wellfield. This research presents the application of geophysics, combining 2D and 3D electrical resistivity tomography surveys and the geological information of a certain area for defining the structural distribution of the underground. Processed electrical resistivity data allow elucidating possible geological units and the thermal behavior of the in-depth materials. Two different assumptions (with different locations of the wells) are designed by using the specific geothermal software GES-CAL. Results show, that Case 1 (based on the geophysical results, so avoiding complex areas) allows the reduction of the global drilling length, and hence, the general initial investment of the system (around 20% lower). Meanwhile, Case 2 (without considering the geophysics) is less economically advantageous and could also present technical difficulties during the drilling process, as well as the possible alteration to the normal system operation. The study highlights the benefits of geophysics as an effective approach to characterize the underground and to help to understand its thermal behavior, which is, in turn, crucial for a proper geothermal design.S

Evaluation of different methodologies for calculating the energy demand and their influence on the design of a low enthalpy geothermal system

The increasing importance of shallow geothermal resources in the decarbonization of heating and cooling systems requires the correct management of all the project stages. One of the fundamental steps in this process is determining the space energy demand, which plays a significant role in the subsequent geothermal design. In the context of Spain, different tools are available for the estimation of the mentioned parameter. For evaluating these procedures, this research applies the principal energy demand calculation tools and uses the outcomes for the later design of the shallow geothermal system. Results show how the Spanish official tools (HULC and CE3X) provide lower energy demand values adjusted to the construction conditions of the building that allow the optimization of the geothermal well field. On the contrary, simpler, and more intuitive applications (regular spreadsheets and GES-CAL) assume higher heating energy demands, which in turn implies an oversizing of the geothermal scheme. Even though all the procedures ensure to cover the energy requirements of the building, the most precise tools manage to reduce the initial investment of the system and its operating costs, in addition to reducing the global CO2 emissions because of the lower power of the associated geothermal heat pump

Estudio de las emisiones de CO2 en una instalación de turbina de gas con diferentes combustibles

El uso de las turbinas de gas en ciclo combinado es una de las alternativas más aceptadas en los últimos tiempos. Existen muchas razones por las que se está investigando sobre la posibilidad de usar otro tipo de combustibles como alternativa al característico, gas natural (metano). Entre otras, se pueden citar: la evolución del precio y la disponibilidad en una zona de algún tipo de gas de síntesis [17] así como estrategias medioambientales y de emisiones [10], [18], [20]. En la bibliografía se encuentran estudios, en los que de forma rigurosa se establece la relación entre la eficiencia de una instalación, usando balances característicos del Segundo Principio de la Termodinámica, y aspectos muy diversos como análisis de los gases de combustión [14], posibilidad de recalentamiento de los gases [19], temperaturas de gasificación [23] y temperatura de llama [18] etc. Estos estudios siempre toman como combustible el metano. En este estudio se presenta un análisis de las emisiones de CO2 (toneladas emitidas) por energía eléctrica producida (MWh) en la instalación de turbina de gas en ciclo combinado usando como combustible los primeros elementos de los hidrocarburos alcanos desde el metano, que se toma como referencia, hasta el heptano. Esto permite la determinación de las emisiones para distintos combustibles con distintas composiciones. Como parámetros relacionados directamente con la eficiencia de la instalación, se han contemplado para cada combustible diferentes temperaturas de entrada a la turbina de gas y distintas relaciones de compresión. Finalmente se obtienen una serie de curvas que relacionan la eficiencia y las emisiones con el número de carbonos presentes en el combustible. El análisis realizado pretende ser un elemento de discusión, basado en aspectos puramente termodinámicos, para la toma de decisione

Investigating the potential of the slurry technology for sustainable pig farm heating

Sustainable energy development in the farming sector is an essential strategy to respond the combined challenge of achieving a reliable and affordable solution but including mitigation and adaptation to climate change. Intensive breeding farms require maintaining an adequate indoor thermal environment that results in high energy demands, usually covered by fossil fuels and electricity. This paper addresses the application of the combined slurry technology for a particular pig farm that currently uses a diesel boiler to supply the piglet heating energy needs. The study also considers different options based on closed ground source heat pump systems. After the design of the slurry alternative and the geothermal ones, notable advantages are detected compared to the existing diesel system. Results show that the implementation of the slurry technology implies an important reduction of the operational costs, which, in turn, involves short amortization periods for this system in relation to the diesel one. Greenhouse gases emissions are also highly reduced in the slurry alternative based on the low electricity use of the heat pump. The environmental side is reinforced by the reduction of polluting substances such as methane of ammonia derived from the descent of temperature of the slurry

Simulation of an Integrated Gasification Combined Cycle with Chemical-Looping Combustion and CO2 sequestration

Chemical-looping combustion allows an integration of CO2 capture in a thermal power plant without energy penalty; secondly, a less exergy destruction in the combustion chemical transformation is achieved, leading to a greater overall thermal efficiency. This paper focus on the study of the energetic performance of this concept of combustion in an integrated gasification combined cycle power plant when synthesis gas is used as fuel for the gas turbines. After thermodynamic modelling and optimization of some cycle parameters, the power plant performance is evaluated under diverse working conditions and compared to a conventional integrated gasification combined cycle with precombustion capture. Energy savings in CO2 capture and storage has been quantified. The overall efficiency increase is found to be significant and even notable, reaching values of around 7%. In order to analyze the influence of syngas composition on the results, different H2-content fuels are considered