Environmental concerns about the effect of greenhouse gases have led governments to regulate industrial CO2 emissions, including through emissions caps, trading and penalties, thus creating economic incentives to reduce CO2 emissions. This research focuses on strategies to reduce CO2 emissions from energy systems in the context of the process industries. In the process industries, energy systems consume fuel to generate steam and power for site process units. Improving energy efficiency can reduce costs of energy generation and use, as well as CO2 emissions. This research develops an integrated design and optimisation methodology for energy systems, allowing effective capture and control of carbon dioxide emissions. The first focus of this study is to develop a systematic approach to evaluate combinatorial strategies for reducing CO2 emissions, based on a techno-economic analysis. A conceptual design procedure with hierarchical decision-making is introduced to combine CO2 emissions reduction strategies, accounting for interactions between site components, including the heat exchanger network and utility system. CO2 emissions reduction options considered in development of this procedure include process integration techniques for improving the energy efficiency of the site and fuel switching. The proposed approach considers trade-offs between the economy of energy retrofit and CO2 emissions penalties. Opportunity for reducing the CO2 penalty is included in the economic evaluation of the combined emissions reduction strategies. A mathematical model for simultaneous optimization of emissions reduction strategies is developed. In addition to emissions reduction strategies, options for trading CO2 allowances are considered in the model. The proposed mathematical method applies Mixed Integer Non Linear Programming (MINLP) optimization, which employs a superstructure of the strategies for CO2 reduction. The proposed mathematical model relates the selected options to their operating and capital costs and to their associated CO2 emissions, allowing the optimizer to search for the optimal combination of emissions reduction strategies. While the reduction in CO2 emissions through process integration techniques is based on the existing configuration of a site and the associated structural limitations, integration of Carbon Capture and Storage (CCS) technologies can provide greater mitigation of CO2 emissions from a site. However, important challenges of implementing CCS in the process industries are the energetic and economic impact of the CCS plant on the integrated site. In the second part of this study, these energy-economic issues are explored. The CCS technologies addressed in this thesis include post- and pre-combustion CO2 capture techniques. Simulation of each capture technique is carried out in process simulation software to characterize the energy performance of the CO2 capture plant. Sensitivity analyses are carried out for key parameters of the CO2 capture plant. The relationship between these key parameters and the energy balance of the capture plant is represented using a simple energy performance model for the CO2 capture plant. This model allows the integration of the CO2 capture plant with the site utility system to be explored. Interactions between the utility system and CO2 capture plant are considered. The site utility system, together with the CO2 capture plant, is optimized for minimum operating cost. The proposed procedures are illustrated by application to a case study of a medium-scale oil refinery. The results illustrate that to reduce CO2 emissions, heat integration, utility system optimization and fuel switching provide more cost-effective solutions than integrating CCS technologies. The mathematical model allows more cost-effective solutions to be identified than using sequential, conceptual methods, but the value of the conceptual method for developing insights is also illustrated. The results demonstrate that, depending on the potential of the site for increasing heat recovery and the type of fuel used on site, solutions that combine energy efficiency and fuel switching can provide up to 40% reduction in site CO2 emissions. Integrating a post-combustion CO2 capture plant with the site utility system can provide up to 90 mol% pure CO2 for sequestration; however, the high capital cost of the capture plant reduces the economic performance of the integrated site. The high heat demand of post-combustion CO2 capture for solvent regeneration increases the fuel consumption of the site and its utility system, which in turn reduces the recovery of CO2. The results reveal that pre-combustion CO2 capture can provide opportunities for heat and power generation to improve the techno-economic performance of the overall integrated site.

Yes / The production of blue ammonia is considered an alternative fuel to reduce CO2 emissions in the ecosystem. Qatar aims to construct the world's largest blue ammonia plant, with an annual capacity of 1.2 million tons (MT), in the first quarter of 2026. Blue ammonia is produced by combining nitrogen with "blue" hydrogen from natural gas feedstocks, with carbon dioxide captured and stored safely. Blue Ammonia can be transported by conventional ships and utilized in power stations to produce low-carbon electricity and potential future applications in decarbonized industries. The new plant will be located in Mesaieed Industrial City (MIC) and operated by QAFCO as part of its integrated facilities. QAFCO is already a significant ammonia and urea producer worldwide, with an annual production capacity of 3.8 million MT of ammonia and 5.6 million MT of urea per annum. Furthermore, QAFCO is the largest producer of urea and ammonia at a single facility worldwide. Qatar Energy Renewable Solutions (QERS) will develop and manage integrated carbon capture and storage facilities to capture and sequester 1.5 MT of CO2 per year for the blue ammonia plant. QERS will also provide more than 35 MW of renewable electricity to the Ammonia-7 facility from its upcoming PV Solar Power Plant in MIC. This project is a step towards reducing the carbon intensity of energy products and is a crucial pillar of Qatar’s sustainability and energy transition strategy to align with Qatar’s 2030 National Vision.

Integrating energy across different sectors is an efficient solution for improving energy systems to meet energy demands with low CO2 emissions. Such integration includes combining the supply and demand of heating, cooling, and electricity by implementing appropriate equipment, as well as combining the energy systems of civic and industrial sectors. This thesis develops various optimization approaches to identify the optimal design and operation of distributed energy systems and the integration of energy systems across commercial, industrial, and transportation sectors, which minimize CO2 emissions and costs of the systems. Available equipment of the energy systems includes combined cooling, heating, and power system, absorption chiller, solar thermal collector, photovoltaic, boiler, electric chiller, battery, ground source heat pump, and air source heat pump. This thesis provides the following contributions to this area. (1) Identify optimal structures of distributed energy systems under different electric grid CO2 footprints. The work implements representative periods when formulating the energy system, which reduces computation time. (2) Differentiate heating demands of entities in the integrated system at different temperature levels to ensure feasible heat transfer. It removes the simplified assumptions in existing studies on the integrated energy system that assume all heating demands are at a uniform temperature. (3) Optimize production rates of plants instead of assuming steady industrial production rates. The switchable production rates lead to a further reduction in CO2 emissions of the integrated system. (4) Identify the environmental and economic benefits of the integrated operation under different electric grid CO2 footprints. It presents that integrated operation reduces more CO2 emissions when the electric grid has higher CO2 footprints. (5) Identify the optimal relative sizes of entities in the integrated system that maximize the CO2 emissions reduction benefits brought by the integrated system. (6) Prove the integrated system has lower CO2 emissions than individual energy systems both under deterministic and stochastic scenarios. Overall, the work in this thesis contributes to developing energy systems and integrated energy systems with the lowest possible CO2 emissions under various scenarios. / Thesis / Doctor of Philosophy (PhD) / As the total population continues to increase worldwide, it is necessary to improve community energy systems to reduce CO2 emissions when meeting energy demands. An efficient solution is integrating energy systems across different sectors. This work explores novel structures of energy systems – integrated energy systems that combine the supply and demand of heating, cooling, and electricity in residential, commercial, industrial, and transportation sectors. The optimal energy system configurations, sizes of subsystems, production rates of plants, heat transfer and electricity transfer, as well as capacity and operation of the equipment, have been identified by developing optimization approaches that minimize CO2 emissions and costs of the integrated system. The optimal design and operation are found under both deterministic and stochastic scenarios and different grid electricity generation scenarios, which provide references for developing community energy systems with the lowest possible CO2 emissions under various scenarios.

Energia é um insumo estratégico na mineração, pois é fundamental na viabilidade das operações mineiras e importante na manutenção de custos operacionais baixos e competitivos. Por esse motivo, toda iniciativa que visa a busca por eficiência no consumo de energia é importante para a competitividade das mineradoras. Vários insumos energéticos são utilizados nas operações unitárias de mineração. Os exemplos mais comuns são diesel, eletricidade, gás natural, carvão e explosivos. O objetivo desse trabalho é estudar, do ponto de vista energético, as atividades realizadas no processo de desmonte de rochas, em um complexo minerador de minério de ferro, visando a melhor utilização da energia no desmonte de rocha para aperfeiçoar as operações unitárias subsequentes de processamento de minérios. Um foco maior foi dado à economia de energia nas moagens de bolas da planta de beneficiamento e concentração, provocada pelas modificações e melhorias realizadas no desmonte de rocha. A metodologia consistiu na análise de diversos desmontes de rocha variando a razão de carga de explosivos no complexo minerador alvo desse trabalho. Os produtos desses desmontes foram acompanhados até a sua entrada na planta de beneficiamento. Durante o processamento desses materiais nas moagens da planta, foram coletadas e analisadas as grandezas elétricas resultantes e comparadas com uma linha de base gerada antes do início do trabalho. Os dados foram analisados com o objetivo de visualizar a influência do aumento da razão de carga na performance energética da operação de moagem. Em paralelo, também, foram analisadas as situações operacionais e dificuldades existentes nas medições de campo e nos acompanhamentos de consumos energéticos dos processos unitários, assim como a infraestrutura necessária para que uma variável tão importante como energia elétrica possa ser monitorada de forma adequada. Por fim, foi abordada a importância, a metodologia e os resultados da redução de emissões de CO2 provenientes da economia de energia de todo o trabalho realizado em campo. Os resultados apresentados mostram que mesmo com um aumento significativo da alimentação de material compacto (maior WI) nas moagens, o consumo energético total dessa operação unitária não aumentou. Isso gerou uma potencial economia específica de energia e a consequente redução de emissões de CO2 na atmosfera, além de viabilizar o processamento de material mais compacto nas mesmas linhas de processo. Esse comportamento sugere que uma melhor energia gasta no desmonte de rocha pode impactar positivamente na produtividade e nos custos de produção do minério ao longo de sua cadeia produtiva. / Energy is a mining strategic source, critical in mining operations feasibility and important to maintain low operational costs in a competitive level. For this reason, any initiative aimed at searching for energy efficiency is important for mining companies’ competitiveness. Mining operations need several energy sources. Most common examples are diesel, electricity, natural gas, coal and explosives. This text aims to address, from an energy perspective, a study carried out in an iron ore mining complex, which had as main objective to reach a better rock blasting energy utilization to improve subsequent mining operations. A greater focus was given to energy savings in ball mills operations of a beneficiation and concentration plant, impacted by modifications and improvements made in rock blasting. Methodology consisted in monitoring several rock blasting, carried out in this mining complex, varying explosive charge ratio. Products of those rock blasting were monitored until they entered the processing plant. During ore processing in plant´s ball mills, electrical variables were collected and analyzed, comparing to a baseline generated before the beginning of this research. All data were analyzed to show influence of explosive charge ratio increase on energy performance of the milling operation. In parallel, operational issues and difficulties in field measurements of energy consumptions were described, as well as the necessary infrastructure that allows the variable electricity to be adequately monitored. Besides, the methodology and results of CO2 emissions reduction from energy savings of all fieldwork were discussed. The research data shows that even with a significant increase in compact feed (higher Work Index), total energy consumption of mill operation did not increase. This scenario generate a potential specific energy savings and consequent reduction in CO2 emissions in the atmosphere. In addition, enables more compact material to be processed in the same process lines. This behavior suggests that a better energy spent on rock blasting can positively affect productivity and ore production costs along its production chain.

Energia é um insumo estratégico na mineração, pois é fundamental na viabilidade das operações mineiras e importante na manutenção de custos operacionais baixos e competitivos. Por esse motivo, toda iniciativa que visa a busca por eficiência no consumo de energia é importante para a competitividade das mineradoras. Vários insumos energéticos são utilizados nas operações unitárias de mineração. Os exemplos mais comuns são diesel, eletricidade, gás natural, carvão e explosivos. O objetivo desse trabalho é estudar, do ponto de vista energético, as atividades realizadas no processo de desmonte de rochas, em um complexo minerador de minério de ferro, visando a melhor utilização da energia no desmonte de rocha para aperfeiçoar as operações unitárias subsequentes de processamento de minérios. Um foco maior foi dado à economia de energia nas moagens de bolas da planta de beneficiamento e concentração, provocada pelas modificações e melhorias realizadas no desmonte de rocha. A metodologia consistiu na análise de diversos desmontes de rocha variando a razão de carga de explosivos no complexo minerador alvo desse trabalho. Os produtos desses desmontes foram acompanhados até a sua entrada na planta de beneficiamento. Durante o processamento desses materiais nas moagens da planta, foram coletadas e analisadas as grandezas elétricas resultantes e comparadas com uma linha de base gerada antes do início do trabalho. Os dados foram analisados com o objetivo de visualizar a influência do aumento da razão de carga na performance energética da operação de moagem. Em paralelo, também, foram analisadas as situações operacionais e dificuldades existentes nas medições de campo e nos acompanhamentos de consumos energéticos dos processos unitários, assim como a infraestrutura necessária para que uma variável tão importante como energia elétrica possa ser monitorada de forma adequada. Por fim, foi abordada a importância, a metodologia e os resultados da redução de emissões de CO2 provenientes da economia de energia de todo o trabalho realizado em campo. Os resultados apresentados mostram que mesmo com um aumento significativo da alimentação de material compacto (maior WI) nas moagens, o consumo energético total dessa operação unitária não aumentou. Isso gerou uma potencial economia específica de energia e a consequente redução de emissões de CO2 na atmosfera, além de viabilizar o processamento de material mais compacto nas mesmas linhas de processo. Esse comportamento sugere que uma melhor energia gasta no desmonte de rocha pode impactar positivamente na produtividade e nos custos de produção do minério ao longo de sua cadeia produtiva. / Energy is a mining strategic source, critical in mining operations feasibility and important to maintain low operational costs in a competitive level. For this reason, any initiative aimed at searching for energy efficiency is important for mining companies’ competitiveness. Mining operations need several energy sources. Most common examples are diesel, electricity, natural gas, coal and explosives. This text aims to address, from an energy perspective, a study carried out in an iron ore mining complex, which had as main objective to reach a better rock blasting energy utilization to improve subsequent mining operations. A greater focus was given to energy savings in ball mills operations of a beneficiation and concentration plant, impacted by modifications and improvements made in rock blasting. Methodology consisted in monitoring several rock blasting, carried out in this mining complex, varying explosive charge ratio. Products of those rock blasting were monitored until they entered the processing plant. During ore processing in plant´s ball mills, electrical variables were collected and analyzed, comparing to a baseline generated before the beginning of this research. All data were analyzed to show influence of explosive charge ratio increase on energy performance of the milling operation. In parallel, operational issues and difficulties in field measurements of energy consumptions were described, as well as the necessary infrastructure that allows the variable electricity to be adequately monitored. Besides, the methodology and results of CO2 emissions reduction from energy savings of all fieldwork were discussed. The research data shows that even with a significant increase in compact feed (higher Work Index), total energy consumption of mill operation did not increase. This scenario generate a potential specific energy savings and consequent reduction in CO2 emissions in the atmosphere. In addition, enables more compact material to be processed in the same process lines. This behavior suggests that a better energy spent on rock blasting can positively affect productivity and ore production costs along its production chain.

Energia é um insumo estratégico na mineração, pois é fundamental na viabilidade das operações mineiras e importante na manutenção de custos operacionais baixos e competitivos. Por esse motivo, toda iniciativa que visa a busca por eficiência no consumo de energia é importante para a competitividade das mineradoras. Vários insumos energéticos são utilizados nas operações unitárias de mineração. Os exemplos mais comuns são diesel, eletricidade, gás natural, carvão e explosivos. O objetivo desse trabalho é estudar, do ponto de vista energético, as atividades realizadas no processo de desmonte de rochas, em um complexo minerador de minério de ferro, visando a melhor utilização da energia no desmonte de rocha para aperfeiçoar as operações unitárias subsequentes de processamento de minérios. Um foco maior foi dado à economia de energia nas moagens de bolas da planta de beneficiamento e concentração, provocada pelas modificações e melhorias realizadas no desmonte de rocha. A metodologia consistiu na análise de diversos desmontes de rocha variando a razão de carga de explosivos no complexo minerador alvo desse trabalho. Os produtos desses desmontes foram acompanhados até a sua entrada na planta de beneficiamento. Durante o processamento desses materiais nas moagens da planta, foram coletadas e analisadas as grandezas elétricas resultantes e comparadas com uma linha de base gerada antes do início do trabalho. Os dados foram analisados com o objetivo de visualizar a influência do aumento da razão de carga na performance energética da operação de moagem. Em paralelo, também, foram analisadas as situações operacionais e dificuldades existentes nas medições de campo e nos acompanhamentos de consumos energéticos dos processos unitários, assim como a infraestrutura necessária para que uma variável tão importante como energia elétrica possa ser monitorada de forma adequada. Por fim, foi abordada a importância, a metodologia e os resultados da redução de emissões de CO2 provenientes da economia de energia de todo o trabalho realizado em campo. Os resultados apresentados mostram que mesmo com um aumento significativo da alimentação de material compacto (maior WI) nas moagens, o consumo energético total dessa operação unitária não aumentou. Isso gerou uma potencial economia específica de energia e a consequente redução de emissões de CO2 na atmosfera, além de viabilizar o processamento de material mais compacto nas mesmas linhas de processo. Esse comportamento sugere que uma melhor energia gasta no desmonte de rocha pode impactar positivamente na produtividade e nos custos de produção do minério ao longo de sua cadeia produtiva. / Energy is a mining strategic source, critical in mining operations feasibility and important to maintain low operational costs in a competitive level. For this reason, any initiative aimed at searching for energy efficiency is important for mining companies’ competitiveness. Mining operations need several energy sources. Most common examples are diesel, electricity, natural gas, coal and explosives. This text aims to address, from an energy perspective, a study carried out in an iron ore mining complex, which had as main objective to reach a better rock blasting energy utilization to improve subsequent mining operations. A greater focus was given to energy savings in ball mills operations of a beneficiation and concentration plant, impacted by modifications and improvements made in rock blasting. Methodology consisted in monitoring several rock blasting, carried out in this mining complex, varying explosive charge ratio. Products of those rock blasting were monitored until they entered the processing plant. During ore processing in plant´s ball mills, electrical variables were collected and analyzed, comparing to a baseline generated before the beginning of this research. All data were analyzed to show influence of explosive charge ratio increase on energy performance of the milling operation. In parallel, operational issues and difficulties in field measurements of energy consumptions were described, as well as the necessary infrastructure that allows the variable electricity to be adequately monitored. Besides, the methodology and results of CO2 emissions reduction from energy savings of all fieldwork were discussed. The research data shows that even with a significant increase in compact feed (higher Work Index), total energy consumption of mill operation did not increase. This scenario generate a potential specific energy savings and consequent reduction in CO2 emissions in the atmosphere. In addition, enables more compact material to be processed in the same process lines. This behavior suggests that a better energy spent on rock blasting can positively affect productivity and ore production costs along its production chain.

[EN] The automotive industry is currently experiencing one of its most rapidly changing periods in recent decades, driven by a growing interest in reducing the negative environmental impacts caused by fossil fuels consumption and the resulting carbon dioxide (CO2) emissions generated during the operation of the internal combustion engine (ICE) which have proven to contribute significantly to Global Warming. Given the fact that a total replacement of the current fleet, dependent of fossil fuels, is unlikely to happen in the immediate future and the urgency to reducing CO2 emissions from transportation in order to tackle Global Warming, it is possible to say that optimizing current ICE technologies and conventional vehicles and engines is a first order priority. Among the technical solutions developed to improve the efficiency of ICE, low viscosity engine oils (LVEO) have emerged as an effective and low-cost method that provides reductions in fuel consumption between 0.5% and 5%. During the development of this thesis, a test plan focused on determining fuel consumption reduction when low viscosity oils are used in light duty vehicles (LDV) and heavy duty vehicles (HDV) were carried out. The test plan has been divided in three parts; the first part was focused on the study of light-duty vehicles (LDV) using one diesel engine representative of the European market. During this part three testing modes were used: comparative motored, fired stationary points and transient homologation cycle tests. All test were performed in the engine test bed. The second part of the study consisted of another comparative test, this time using a different engine oils in a HDV fleet. The study was conducted using the urban buses fleet of the city of Valencia, including 3 buses models , with 2 different powertrain technologies. The third part of the study was focused on the friction coefficient behavior within the engine tribological pairs making comparative tests in two specialized tribometers; one of reciprocating action to simulate the lubrication conditions in the piston ring-cylinder liner contact and a "ball-on-disk" tribometer to simulate the lubrication in the distribution system. The various comparative studies have served to analyze how the friction and fuel consumption responded when LVEO were used both in the ICE and the complete vehicle contexts. The fuel consumption benefit found during the test was used to calculate the carbon footprint reduction when LVEO were used. / [ES] Actualmente la industria de la automoción vive uno de los periodos de cambio más vertiginosos de las últimas décadas, marcado por un creciente interés en reducir los impactos medioambientales negativos generados por el consumo de combustibles fósiles y sus consecuentes emisiones nocivas de dioxido de carbono (CO2) generados durante el funcionamiento del motor de combustión interna alternativo (MCIA). Teniendo en cuenta que el proceso de sustitución de la flota actual por una totalmente independiente de los combustibles fósiles puede tomar varias décadas, y ante la urgencia inmediata de reducir las emisiones de CO2, se puede decir que actualmente es más urgente hacer una optimización de los vehículos con motorizaciones convencionales. Entre las soluciones técnicas que se han desarrollado para mejorar la eficiencia del MCIA destaca la utilización de aceites de baja viscosidad como un método efectivo y de bajo coste de implementación que brinda reducciones del consumo entre el 0.5% y el 5%. Durante el desarrollo de esta tesis se ha llevado a cabo un plan de ensayos enfocado en determinar valores concretos de ahorro de combustible esperados cuando se utilizan aceites de baja viscosidad en vehículos de trabajo ligero y pesado. El plan de estudios se dividió en tres partes; la primera se centró en el estudio de MCIA de vehículos de trabajo ligero, utilizando un motor Diesel representativo del mercado Europeo y llevando a cabo pruebas comparativas en arrastre, puntos de funcionamiento estacionarios y ciclos transitorios de homologación. La segunda parte del estudio consta de otro ensayo comparativo, esta vez utilizando una flota de vehículos de trabajo pesado. El estudio se realizó con la flota de autobuses urbanos de la ciudad de Valencia, incluyéndose 3 modelos de autobuses, con 2 tipos de motorización diferente. La tercera parte del estudio se centró en el comportamiento del coeficiente de friction en los pares tribológicos del motor haciendo ensayos comparativos con tribómetros especializados; uno de movimiento alternativo para simular las condiciones de la interfaz piston-camisa y un "bola y disco" para simular la lubricación en el sistema de distribución, específicamente en la interfaz leva-taqué. Los diversos estudios comparativos han servido para analizar como es la respuesta general de la fricción y el consumo de combustible cuando se usan aceites de baja viscosidad, tanto a nivel de motor como para la totalidad del vehículo, encontrando diferencias de par en los ensayos de arrastre, de consumo específico de combustible en los ensayos de motor en estado estacionario y diferencias totales de consumo de combustible en los ensayos en régimen transitorio y en flota, que a su vez han permitido estimar la reducción esperada en la huella de carbono. / [CAT] Actualment la indústria de l'automoció viu un dels períodes de canvi més vertiginoses de les últimes dècades, marcat per un creixent interès en reduir els impactes mediambientals negatius generats pel consum de combustibles fòssils i els seus conseqüents emissions nocives de diòxid de carboni (CO2) generats durant el funcionament del motor de combustió interna alternatiu (MCIA). Tenint en compte que el procés de substitució de la flota actual per una totalment independent dels combustibles fòssils pot prendre diverses dècades, i davant la urgència immediata de reduir les emissions de CO2, es pot dir que actualment és més urgent fer una optimització dels vehicles amb motoritzacions convencionals. Entre les solucions tècniques que s'han desenvolupat per millorar l'eficiència del MCIA destaca la utilització d'olis de baixa viscositat com un mètode efectiu i de baix cost d'implementació que brinda reduccions del consum entre el 0.5% i el 5%. Durant el desenvolupament d'aquesta tesi s'ha dut a terme un pla d'assajos enfocat a determinar valors concrets d'estalvi de combustible esperats quan s'utilitzen olis de baixa viscositat en vehicles de treball lleuger i pesat. El pla d'estudis es va dividir en tres parts; la primera es va centrar en l'estudi de MCIA de vehicles de treball lleuger, utilitzant un motor dièsel representatiu del mercat Europeu i portant a terme proves comparatives en arrossegament, punts de funcionament estacionaris i cicles transitoris d'homologació. la segona part de l'estudi consta d'un altre assaig comparatiu, aquest cop utilitzant una flota de vehicles de treball pesat. L'estudi es va realitzar amb la flota d'autobusos urbans de la ciutat de València, incloent-se 3 models d'autobusos, amb 2 tipus de motorització diferent. La tercera part de l'estudi es va centrar en el comportament del coeficient de friction en els parells tribològics del motor fent assajos comparatius amb tribómetros especialitzats; Un acció reciprocante per simular les condicions del piston camisa i un bola i disc per simular la lubricació en el sistema de distribució. Els diversos estudis comparatius han servit per analitzar com és la resposta general de la fricció i el consum de combustible quan es fan servir olis de baixa viscositat, tant a nivell de motor com la totalitat del vehicle, trobant diferències de bat a els assajos d'arrossegament, de consum específic de combustible en els assajos de motor en estat estacionari i diferències totals de consum de combustible en els assajos en règim transitori i en flota, que al seu torn han permès calcular la reducció en la petjada de carbono. / Ramírez Roa, LA. (2016). Contribution to the Assessment of the Potential of Low Viscosity Engine Oils to Reduce ICE Fuel Consumption and CO2 Emissions [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73068 / TESIS