MODELLING AND EXPERIMENTAL VALIDATION OF AN INNOVATIVE COAXIAL HELICAL BOREHOLE HEAT EXCHANGER FOR A DUAL SOURCE HEAT PUMP SYSTEM

[ES] La energía geotérmica de baja entalpía es una alternativa eficiente y renovable a los sistemas convencionales para proporcionar calefacción, refrigeración y producir agua caliente sanitaria (ACS) de forma sostenible. El proyecto GEOTeCH plantea el desarrollo de sistemas con bomba de calor geotérmica más eficientes y con un coste menor en comparación con el mercado. Para ello, se ha desarrollado un nuevo tipo de intercambiador enterrado coaxial con flujo helicoidal en el tubo externo que presenta una mayor eficiencia y permite reducir la longitud de intercambiador a instalar, así como una bomba de calor dual con compresor de velocidad variable, capaz de trabajar con el terreno o el aire como fuente/sumidero, seleccionando la que proporcione un mejor rendimiento del sistema. El principal objetivo es desarrollar un sistema eficiente y replicable para proporcionar calefacción, refrigeración y producir ACS en el sector de mercado de pequeños edificios con un tamaño menor en el campo de intercambiadores enterrados y un aumento de la eficiencia. Para demostrar la aplicabilidad de estos sistemas, se han construido tres instalaciones demostración en tres países europeos. En esta tesis doctoral se ha desarrollado un modelo dinámico completo del sistema en el software TRNSYS, capaz de reproducir el comportamiento de los diferentes componentes y del sistema en general. Este modelo constituye una herramienta útil para el desarrollo y análisis de diferentes estrategias de control sin la necesidad de implementarlas en instalaciones reales, así como analizar el comportamiento del sistema funcionando bajo condiciones diferentes. Para este propósito, es necesario desarrollar modelos detallados de los nuevos componentes desarrollados en el proyecto: el intercambiador enterrado coaxial helicoidal y la bomba de calor dual; para poder acoplarlos al resto de componentes en el modelo completo del sistema. Por ello, se ha desarrollado un modelo dinámico del nuevo intercambiador, capaz de reproducir con precisión el comportamiento a corto plazo del intercambiador, enfocado a la evolución de la temperatura del fluido, y se ha validado con datos experimentales en diferentes condiciones de operación. Para poder reproducir no solo el comportamiento dinámico del intercambiador enterrado, sino también la respuesta a largo plazo del terreno y la interacción entre intercambiadores en un campo, se ha desarrollado otro modelo en TRNSYS que realiza esta función. De esta manera, al acoplar ambos modelos es posible reproducir el comportamiento a corto plazo del intercambiador enterrado a la vez que la respuesta a largo plazo del terreno. Por otro lado, se ha implementado en TRNSYS un modelo de la bomba de calor dual desarrollado. Con este modelo es posible calcular la capacidad de la bomba de calor dependiendo del modo de operación en que esté funcionando, de la frecuencia del compresor y otras variables y condiciones de operación. El modelo del sistema dual en TRNSYS se ha utilizado para hacer un análisis de su comportamiento funcionando en diferentes climas, para ello se han seleccionado tres ciudades en España y en Europa con diferentes climas y se han realizado simulaciones del sistema funcionando en cada ciudad. Por otro lado, también se ha modelado en TRNSYS una de las instalaciones demostración del proyecto GEOTeCH, incluyendo el edificio climatizado y el acoplamiento con los fan coils. Con este modelo se estudia una nueva estrategia para controlar la frecuencia del compresor en base a la temperatura de las habitaciones, en lugar de controlarla en base a la temperatura de suministro, con el objetivo de reducir el consumo del compresor cuando ya se haya conseguido el confort. Además, otras estrategias de optimización se han analizado con el modelo.Por tanto, los modelos desarrollados constituyen herramientas útiles para ayudar en el diseño del sistema y los diferentes componentes, el análisis de su comportamiento y el d[CA] L'energia geotèrmica de baixa entalpia es planteja com una alternativa eficient i renovable als sistemes convencionals per proporcionar calefacció, refrigeració i produir aigua calenta sanitària (ACS) de forma sostenible. El projecte GEOTeCH planteja el desenvolupament de sistemes amb bomba de calor geotèrmica més eficients i amb un cost menor en comparació amb el mercat. Per a això, s'ha desenvolupat un nou tipus d'intercanviador enterrat coaxial amb flux helicoïdal en el tub extern que presenta una major eficiència i permet reduir la longitud a instal·lar, així com una bomba de calor dual amb compressor de velocitat variable, capaç de treballar amb el terreny o l'aire com a font, seleccionant la que proporcione un millor rendiment. Aquests components s'utilitzen en el nou sistema amb bomba de calor dual. El principal objectiu és desenvolupar un sistema eficient i replicable per proporcionar calefacció, refrigeració i produir ACS en edificis xicotets amb una grandària menor d'intercanviadors soterrats i un augment de l'eficiència. Per demostrar l'aplicabilitat d'aquests sistemes, s'han construït tres instal·lacions demostració en Itàlia, Països Baixos i Regne Unit. En aquesta tesi s'ha desenvolupat un model dinàmic complet del sistema en TRNSYS, capaç de reproduir el comportament dels components i del sistema en general. Aquest model constitueix una eina útil per al desenvolupament i anàlisi de diferents estratègies de control sense la necessitat d'implementar-les en instal·lacions reals, així com analitzar el comportament del sistema funcionant en condicions diferents. Per a això, cal desenvolupar models detallats dels nous components desenvolupats en el projecte: l'intercanviador enterrat i la bomba de calor dual; per poder acoblar-los a la resta de components. Per això, s'ha desenvolupat un model dinàmic del nou intercanviador enterrat, capaç de reproduir amb precisió el comportament a curt termini de l'intercanviador, enfocat a l'evolució de la temperatura del fluid, i s'ha validat amb dades experimentals en diferents condicions d'operació. Per a poder reproduir no només el comportament dinàmic de l'intercanviador soterrat, sinó també la resposta a llarg termini del terreny i la interacció entre intercanviadors en un camp, s'ha desenvolupat un altre model en TRNSYS que realitza aquesta funció. D'aquesta manera, en acoblar els dos models és possible reproduir el comportament a curt termini de l'intercanviador enterrat, al mateix temps que la resposta a llarg termini del terreny. D'altra banda, s'ha implementat en TRNSYS un model de la bomba de calor. Amb aquest model és possible calcular la capacitat de la bomba de calor depenent del mode d'operació en què estiga funcionant, de la freqüència del compressor i altres variables i condicions d'operació. El model del sistema dual en TRNSYS s'ha utilitzat per a fer una anàlisi del seu comportament funcionant en diferents climes, per a això s'han seleccionat tres ciutats a Espanya i tres a Europa amb diferents climes i s'han realitzat simulacions del sistema funcionant en cada ciutat durant un any. S'ha analitzat l'eficiència del sistema en cada ciutat, així com l'ús de cadascuna de les fonts (aire / terreny). D'altra banda, també s'ha modelat en TRNSYS una de les instal·lacions demostració del projecte GEOTeCH, incloent l'edifici d'oficines climatitzat i l'acoblament amb els fan coils. Amb aquest model es pretén estudiar una nova estratègia per a controlar la freqüència del compressor d'acord amb la temperatura de les habitacions, en lloc de controlar-la en base a la temperatura de subministrament, amb l'objectiu de reduir el consum del compressor quan les habitacions ja es troben en condicions de confort. A més, altres estratègies d'optimització s'han analitzat amb el model. Per tant, els models desenvolupats constitueixen eines útils per ajudar en el disseny del sistema i els diferents components, l'anàlisi del[EN] Low enthalpy geothermal energy is considered as an efficient and renewable alternative to conventional systems to provide heating, cooling and Domestic Hot Water (DHW) production in a sustainable way. In this context, the GEOTeCH project proposes the development of more efficient geothermal heat pump systems with a lower cost compared to the market. To this end, a new type of coaxial Borehole Heat Exchanger (BHE) with helical flow through the outer tube has been developed, which presents a higher efficiency and allows to reduce the length of the heat exchanger to be installed, as well as a Dual Source Heat Pump (DSHP) with variable speed compressor, capable of working with the ground or air as a source / sink, selecting the one that provides the best performance of the system. These components are used in the new DSHP system developed. The main objective is to develop efficient and replicable systems to provide heating, cooling and DHW in the market sector of small buildings with a smaller size of the BHE field and an increase in the efficiency. To demonstrate the applicability of these systems, three demonstration facilities have been installed in Italy, the Netherlands and the UK. In this thesis, a complete dynamic model of the system has been developed in the TRNSYS software, capable of reproducing the behavior of the different components and the system in general. This model is a useful tool for the development and analysis of different control strategies without the need to implement them in real installations, as well as analyses the behavior of the system operating under different conditions. For this purpose, it is necessary to develop detailed models of the new components developed in the project: the BHE and the DSHP; to couple them to the rest of the components of the system. For this reason, a dynamic model of the new BHE was developed, able to accurately reproduce its short-term behavior, focused on the evolution of the fluid temperature, and validated with experimental data in different operating conditions. In order to reproduce not only the dynamic behavior of the BHE, but also the long-term response of the ground and the interaction between BHEs in a field, another model was developed in TRNSYS. In this way, by coupling both models, it is possible to reproduce the short-term behavior of the BHE as well as the long-term response of the ground. On the other hand, a model of the DSHP was implemented in TRNSYS. With this model, it is possible to calculate the capacity of the heat pump depending on the operating mode in which it is operating, the frequency of the compressor and other variables and operating conditions. The model of the hybrid system in TRNSYS has been used to make an analysis of its behavior working in different climatic conditions, for which three cities have been selected in Spain and three in Europe, with different climates. So, different simulations of the system have been carried out in each city for one year. The efficiency of the system in each city has been analyzed, as well as the use of each of the sources (air / ground). On the other hand, one of the demo-sites of the GEOTeCH project, including the conditioned office building and the coupling with the fan coils, has also been modelled in TRNSYS. With this model, it is studied a new strategy to control the frequency of the compressor based on the temperature of the rooms, instead of controlling it based on the supply temperature, with the aim of reducing the consumption of the compressor when the rooms are already in comfort conditions. In addition, other optimization strategies have been analyzed with the model. Therefore, the models developed, both for the BHE and the system, are able to reproduce their operation and can be used as virtual installations, constituting useful tools to help in the design of the system and the different components, the analysis of their behavior and the development of optimization strategies.I would like to acknowledge the financial support that has made this PhD thesis possible. The present work has been supported by the European Community Horizon 2020 Program for European Research and Technological Development (2014-2020) inside the framework of the project 656889 – GEOTeCH (Geothermal Technology for Economic Cooling and Heating), also by the Generalitat Valenciana inside the program “Ayudas para la contratación de personal investigador en formación de carácter predoctoral (ACIF/2016/131)” and by the Institute for Energy Engineering of the Universitat Politècnica de València.Cazorla Marín, A. (2019). MODELLING AND EXPERIMENTAL VALIDATION OF AN INNOVATIVE COAXIAL HELICAL BOREHOLE HEAT EXCHANGER FOR A DUAL SOURCE HEAT PUMP SYSTEM [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/125696TESI

A novel TRNSYS type of a coaxial borehole heat exchanger for both short and mid term simulations: B2G model

[EN] A dynamic model of a ground source heat pump system is a very useful tool in order to optimize its design and operation. In order to fairly predict the performance of such a system, the dynamic evolution of the fluid entering the heat pump and coming from the borehole heat exchanger (BHE) must be accurately reproduced not only in the long term but also in the short-mid term operating conditions, as it directly affects the coefficient of performance of the heat pump unit. In this context, the B2G model was developed to reproduce the short-term dynamic evolution of the fluid temperature inside the BHE. This work presents the new upgraded version of the B2G dynamic model for a coaxial BHE, which includes several new features to better reproduce not only the short-term but also the mid-term behaviour of the BHE. For that purpose, the model of the surrounding ground has been improved: vertical heat conduction in the grout and ground, heterogenous ground with different layers, and a higher number of ground nodes in the thermal network considered in the model were added, which are automatically located by means of polynomial correlations for any type of ground, geometry and operating conditions. This novel approach has been implemented in TRNSYS for accurately modelling the dynamic behaviour of a coaxial BHE with low computational cost (2.5¿s for a 24¿h simulation period in a modern computer). The model has been validated against experimental data from a dual source heat pump installation in Tribano (Padua, Italy) and has proven capable of accurately reproducing the short-mid term (up to five days) behaviour of the BHE, with a deviation lower than 0.12¿K.The present work has been supported by the European Community Horizon 2020 Program for European Research and Technological Development (2014-2020) inside the framework of the project 656889 –GEOTeCH (Geothermal Technology for Economic Cooling and Heating) and by the Generalitat Valenciana inside the program “Ayudas para la contratación de personal investigador en formación de carácter predoctoral (ACIF/2016/131)”.Cazorla-Marín, A.; Montagud- Montalvá, C.; Tinti, F.; Corberán, JM. (2019). A novel TRNSYS type of a coaxial borehole heat exchanger for both short and mid term simulations: B2G model. Applied Thermal Engineering. 164(114500):1-15. https://doi.org/10.1016/j.applthermaleng.2019.114500S11516411450

Modelling of a solar heat for industrial process (ship) system using fresnel collectors

The Solar Heat for Industrial Process (SHIP) systems has been pushed forward in recent years as an option to achieve the goal of decarbonizing the industrial sector. In this way, it is possible to partially cover the heat necessities from the industry with these systems and then save fuel consumption. Fresnel solar energy concentrators have proved to be a state-of-the-art technology to be implemented for heat generation in SHIP systems. In this work, a quasi-dynamic model for the simulation of operation and performance of a SHIP system with Fresnel collectors solar field and the dynamics and inertia of a kettle reboiler has been developed. The preliminary validation of the model has been performed using experimental data obtained from the SOLPINVAP experimental plant in Almazora, Spain.Thanks to the company SOLATOM CSP, for all the information and operatoinal data from the SHIP facility used in the present work. This work was partially supported by the Research and Development Aid Program (PAID-01-20) of the Universitat Politècnica de València for receiving the Research Fellowship FPI-UPV- 2020. This publication has been carried out in the framework of the project “DECARBONIZACIÓN DE EDIFICIOS E INDUSTRIAS CON SISTEMAS HÍBRIDOS DE BOMBA DE CALOR”, funded by the Spanish “Ministerio de Ciencia e Innovación (MCIIN)” with code number PID2020-115665RB-I00

Dual source heat pump, a high efficiency and cost-effective alternative for heating, cooling and DHW production

[EN] This article presents the characteristics and performance of an innovative dual source heat pump (DSHP) for heating, cooling and domestic hot water (DHW) production. The research work was carried out in the framework of the H2020 European project: Geot€ch `GEOthermal Technology for economic Cooling and Heating¿. The DSHP is able to choose the most favourable source/sink in such a way that it can work as an air-to-water heat pump using the air as a source/sink, or as a brine-to-water heat pump coupled to the ground. The DSHP is manufactured as an outdoor `plug & play¿ unit, working with R32 refrigerant and including a variable speed compressor, which gives full capabilities for an efficient modulating operation. The DSHP was fully characterized in steady state conditions at the IUIIE laboratory. In order to assess its dynamic performance and to identify key control strategies to optimize its annual operation, a complete integrated model of the DSHP system in TRNSYS including the DSHP and all the other system components was developed. A first energy assessment, carried out for an office building located in the Netherlands, proves that the DSHP system would be able to reach a similar efficiency than a pure ground source heat pump (GSHP) system with half the ground source heat exchanger area needed. Therefore, the DSHP system could become a cost-effective alternative solution for heating, cooling and DHW production in buildings, as the initial investment would be significantly reduced compared to GSHPs, with similar or even higher energy efficiency.The present work has been supported by the European Union under the Horizon 2020 Framework Programme for European Research and Technological Development (2014-20) inside the framework of the project 656889-GEOTeCH (Geothermal Technology for Economic Cooling and Heating). Additionally, funding was received by the Generalitat Valenciana inside the programme 'Ayudas para la contratacion de personal investigador en formacion de caracter predoctoral (ACIF/2016/131)' and by the Ministerio de Educacion, Cultura y Deporte inside the programme 'Formacion de Profesorado Universitario (FPU15/03476)'.Corberán, JM.; Cazorla-Marín, A.; Marchante-Avellaneda, J.; Montagud, C. (2018). Dual source heat pump, a high efficiency and cost-effective alternative for heating, cooling and DHW production. International Journal of Low-Carbon Technologies (Online). 13(2):161-176. https://doi.org/10.1093/ijlct/cty008S16117613

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

Energy Analysis and Cost-Effective Design Solutions for a Dual-Source Heat Pump System in Representative Climates in Europe

Ground-source heat pumps are an efficient technology for heating and cooling in buildings. However, the main limitation of their widespread application is the borehole heat exchanger’s (BHE) high investment cost. Hybridizing GSHP systems may overcome this limitation. This research work analyzes the long-term energy performance of a dual-source heat pump (DSHP) system, which uses the air or the ground as external heat/sink sources, in three representative European climates. First, a BHE cost-effective design solution is proposed for each climatology; then, a complete energy analysis is carried out, and the optimal source control parameters that best enhance the system performance in each climate are determined with the use of a complete dynamic model of the DSHP system developed in TRNSYS. Simulations were carried out for a 25-year operation period. Results show that the DSHP maintains the efficiency during the simulated period, with deviations lower than 1.7% in all cases. Finally, the source control optimization method results in only slight efficiency gains (<0.35%) but with a stronger effect on the ground/air use ratio (up to 25% use of air in cold climates), reducing the thermal imbalance of the ground and leading to a consequent BHE size length and cost reduction

Low-Pressure Steam Generation with Concentrating Solar Energy and Different Heat Upgrade Technologies: Potential in the European Industry

[EN] The industry is currently responsible for around 21% of the total CO2 emissions, mainly due to heat production with fossil fuel burners. There are already different technologies on the market that can potentially reduce CO2 emissions. Nevertheless, the first step for their introduction is to analyze their potential on a global scale by detecting in which countries each of them is more attractive, given their energy prices and resources. The present work involves a techno-economic analysis of different alternatives to replace industrial gas boilers for low-pressure steam production at 120 °C and 150 °C. Solar Heat for Industrial Processes (SHIP) was compared with Electric Boilers (EBs), High-Temperature Heat Pumps (HTHPs), and Absorption Heat Transformers (AHTs). SHIP systems have the potential to reach payback periods in the range of 4 to 5 years in countries with Direct Normal Irradiance (DNI) values above 1400 kWh/m2/year, which is reached in Spain, Italy, Greece, Portugal, and Romania. HTHPs and AHTs lead to the lowest payback periods, Levelized Cost of Heat (LCOH), and highest CO2 emission savings. For both AHTs and HTHPs, payback periods of below 1.5 years can be reached, particularly in countries with electricity-to-gas price ratios below 2.0.This work was partially funded by the grant agreement No. 101069689 (PUSH2HEAT project) of the European Union s Horizon 2020 research and innovation program, and by the Spanish Agencia Estatal de Investigación (AEI) for the project Generación de vapor para la industria utilizando reflectores lineales Fresnel (SolarSteam4IND, TED2021-130614A-I00) in the framework of Proyectos de transición ecológica y transición digital 2021 . In addition, the financial support of the Swiss Federal Office of Energy SFOE as part of the SWEET (SWiss Energy research for the Energy Transition) project DeCarbCH (www.sweet-decarb.ch (accessed on 17 February 2024)) is gratefully acknowledged.Payá-Herrero, J.; Cazorla-Marín, A.; Arpagaus, C.; Corrales Ciganda, JL.; Hassan, A. (2024). Low-Pressure Steam Generation with Concentrating Solar Energy and Different Heat Upgrade Technologies: Potential in the European Industry. Sustainability. 16(5). https://doi.org/10.3390/su1605173316