In this work the crystallization of citric acid using Tahiti lemon juice was studied. The experiments were carried out in a batch crystallizer, with agitation and temperature control. The influences of three variables according to a composite experimental design on the production of citric acid were analyzed: super saturation, crystal number (seeding) and speed stirred. The effects of these variables and their interactions were analyzed by the response surface methodology. The biggest influences were exerted by supersaturation and by speed stirred. Through a canonic analysis of the adjusted response surface, the optimal variables values that led to the biggest production of citric acid were determined: R = 356 rpm (speed stirred); S = 1.26 super saturation and N = 27 seeding. In these conditions, the relations of the crystal mass and seed mass for citric acid (y) reached 2.2700. A kinetic study into the growth from the crystal of citric acid showed that the average increase of the mass of crystals was 1.375x10-6 kg (102% of the initial mass) and it showed presented an average increase of the characteristic dimensions of 0.48x10-3 m after two hours of crystallization. The calculated growth rate decreases throughout the time, probably because of the reduction of the driving force and for the dependence that the growth rate of crystals has in related to the size of the same ones. Being that lesser crystals possess bigger growth rate that the crystals biggest not following. The smaller crystals show a larger growth rate than the bigger crystals and crystallization didn t follow the McCabe ΔL law. The kinetic study of the growth rate showed that KG changed through the experiments, probably because of hydrodynamic influence in the agitation, that is, bigger particles behave in a different way from smaller particles on the crystallizer in a certain agitation. / Neste trabalho estudou-se a cristalização do ácido cítrico, que foi extraído do suco do limão Tahiti. Os experimentos foram realizados em um cristalizador operando em batelada, com controles de agitação e temperatura. Foram analisadas as influências de três variáveis sobre a produção do ácido cítrico: grau de supersaturação, número de partículas de ácido cítrico compondo a semeadura (sementes) e velocidade de agitação. Os efeitos dessas variáveis e de suas interações foram analisados pela metodologia da superfície de resposta. As maiores influências foram exercidas pela supersaturação e pela velocidade de agitação. Realizando uma análise canônica da superfície de resposta ajustada, determinaram-se os valores ótimos das variáveis que levaram à máxima produção de ácido cítrico: de 356 rpm e supersaturação S= 1,26; utilizando 27 sementes. Nestas condições, a relação massa de cristais pela massa de sementes (y) para o ácido cítrico alcança o valor de 2,2700. Um estudo cinético do crescimento dos cristais de ácido cítrico revelou que o aumento médio da massa dos cristais foi de 1,375x10-6 kg e o aumento médio das dimensões características de 0,48x10-3 m, para o tempo de 2,5 horas de cristalização. A taxa de crescimento calculada diminui ao longo do tempo de cristalização, provavelmente, pela diminuição da força motriz e pela dependência que a taxa de crescimento dos cristais tem em relação ao tamanho dos mesmos. Os cristais menores apresentam taxas de crescimento maiores que os cristais maiores e a cristalização não seguiu a lei ΔL de McCabe. O estudo cinético da taxa crescimento mostrou que KG variou ao longo dos experimentos, provavelmente pela influência hidrodinâmica na agitação, ou seja, partículas maiores se comportam de maneira diferente das partículas menores no leito de cristalização numa dada agitação. / Mestre em Engenharia Química

This thesis report provides a comprehensive analysis of the regulatory landscape governing Battery Energy Storage Systems (BESS) in Spain and offers insights into their operational optimization and economic viability. The study centers on a 40 MW BESS and explores three distinct case studies, each representing varying system durations (one, two, and four hours) and two different electricity price scenarios (2019 and 2022). A techno-economic analysis encompassing all scenarios concludes the investigation. The research findings reveal that BESS projects can be financially lucrative when operating under the 2022 scenario, particularly when participating in Spain's Wholesale and Secondary Regulation service (aFRR) markets. Notably, as the system duration increases, project profitability also rises, with Net Present Values (NPVs) amounting to 29.6 M€, 50.4 M€, and 80.6 M€ for one-hour, two-hour, and four-hour BESS durations, respectively. However, this trend is not consistent, as observed in the 2019 scenario, where the opposite holds true due to significantly lower prices in both Wholesale and Secondary Regulation service markets, resulting in negative NPVs that increase with longer BESS durations (specifically, -3.3 M€, -6.9 M€, and -17.7 M€ for one-hour, two-hour, and four-hour BESS durations, respectively). In terms of optimal dispatching strategy, the study identifies consistent patterns across all case studies and scenarios. The BESS prioritizes participation in the Secondary Regulation service due to its higher remuneration compared to arbitrage activities in the Wholesale market. Despite Spain's efforts to promote the adoption of BESS technologies, several barriers exist that could impede their deployment. Key challenges include the absence of Capacity Markets (CM), restrictions on BESS participation in technical constraints and black-start markets, and the lack of remunerated markets for Frequency Control Reserve (FCR) and voltage control. In summary, this study highlights the need for a more investor-friendly environment characterized by greater revenue stream certainty and streamlined administrative processes. / Denna avhandling ger en omfattande analys av den reglerande landskapskontexten som styr batterilagringssystem (BESS) i Spanien och ger insikter om deras drifts- och ekonomiska livskraft. Studien fokuserar på en 40 MW BESS och utforskar tre olika fallstudier, var och en representerar varierande systemtider (en, två och fyra timmar) och två olika elprisscenarier (2019 och 2022). En teknisk-ekonomisk analys som omfattar alla scenarier avslutar undersökningen. Forskningsresultaten visar att BESS-projekt kan vara ekonomiskt lönsamma när de verkar enligt 2022-scenariot, särskilt när de deltar i Spaniens grossist- och sekundärregleringstjänst (aFRR) marknader. Inte minst ökar lönsamheten i projektet när systemtiden förlängs, med nuvärdet (NPV) uppgår till 29,6 M€, 50,4 M€ och 80,6 M€ för BESS-varaktigheter på en timme, två timmar respektive fyra timmar. Denna trend är dock inte konsekvent, som observerats i 2019-scenariot, där motsatsen gäller på grund av betydligt lägre priser både på grossist- och sekundärregleringsmarknaderna, vilket resulterar i negativa NPV-värden som ökar med längre BESS-varaktigheter (specifikt -3,3 M€, -6,9 M€ och -17,7 M€ för BESS-varaktigheter på en timme, två timmar respektive fyra timmar). När det gäller optimal distributionsstrategi identifierar studien liknande mönster i alla fallstudier och scenarier. BESS prioriterar deltagande i sekundärregleringstjänsten på grund av dess högre ersättning jämfört med arbitrageaktiviteter på grossistmarknaden. Trots Spaniens ansträngningar att främja antagandet av BESS-teknologier finns det flera hinder som kan hämma deras utrullning. Viktiga utmaningar inkluderar frånvaron av kapacitetsmarknader (CM), begränsningar för BESS-deltagande i tekniska begränsningar och svartstartmarknader, samt avsaknaden av marknader med ersättning för frekvensreglering (FCR) och spänningsreglering. Sammanfattningsvis belyser denna studie behovet av en mer investerarvänlig miljö präglad av större säkerhet i intäktsströmmar och förenklade administrativa processer.

Energy supply in Sweden year 2011 amounted to 577 TWh. The final energy consumption for industrial, residential and service was 379 TWh. Sweden has energy policy goals to reduce energy use in buildings. One of these goals is to reduce the energy use by 20 % in 2020 compared to the year 1995. An important step to achieve this goal is to target energy efficiency measures in existing buildings. There are also financial incentives to implement energy efficiency measures due to the fact that the cost of energy represents 30-40% of a buildings maintenance costs. In general, up to 20 % of the energy consumption can be reduced without major reconstruction. In this master thesis project presented here, an energy audit was performed and energy efficiency measures was proposed for an existing building located at Järfälla, Stockholm. The property belongs to SAAB - Defence and Security. They have an internal target to reduce energy use in their buildings with 50 % by 2015 compared to 2009. The work of this master thesis project was limited to a building locally termed hus A. This part of the property is the oldest and was built in 1968, but has expanded gradually to the year 1977. Hus A contains of offices, a production hall, laboratories and storage areas. The energy audit showed that the electricity use is far greater in hus A, compared to the an average office and administration building. This is mainly due to production processes. A breakdown of the highest electricity consumers are: Industrial processes – 61.9 kWh/m2/year Lighting – 35.7 kWh/m2/year Fans – 33.2 kWh/m2/year Refrigeration – 21.8 kWh/m2/year Compressed air – 18.9 kWh/m2/year Computer units – 7.8 kWh/m2/year Frequency converters – 4.4 kWh/m2/year Waste heat from industrial processes, primarily from the production hall leads to high cooling demand to maintain good thermal comfort. Limitations in operation control of the buildings HVAC (Heating, Cooling and Air-conditioning) systems causes high heating and cooling demand and hence the buildings thermal mass is not properly utilized. Energy saving measures was mainly focused on increasing the controlling capability of HVAC systems. By implementing the energy efficiency measures presented in this master thesis report, building thermal mass will be more efficiently utilized. In addition, end use of electricity, heat and cooling will be reduced. In total, seven energy-saving measures proposed.  One measure is implemented to prevent heating and cooling at the same time. A brief description of the energy efficiency measures and the expected result is found below. Adjust set point for TAFA301 Energy saving: 94.0 MWh/yearPayback time: 0 year Establish time schedule for compressed air systemEnergy saving: 110.8 MWh/yearPayback time: 2.5 months Demand controlled temperature set point to heating systemEnergy saving: 167.0 MWh/yearPayback time: 3.5 months Demand control of airflow in the production hallEnergy saving: 155,5 MWh/yearPayback time: 2 years and 10 months Establish time schedule for frequency invertersEnergy saving: 104.0 MWh/yearPayback time: 3 years and 2 months Radiator thermostats to the first part of the production hall Energy saving: 6.5 MWh/yearPayback time: 5 years and 2 months Demand control of airflow in conference roomsEnergy saving: 11.0 MWh/yearPayback time: 12 years and 2 months

Studien är utförd åt Freezing Food Småland Öland AB. Syftet med undersökningen var att ge förslag på åtgärder som minskar anläggningens energibehov samt att beräkna återbetalningstid för åtgärder. Genom användningen av simuleringsprogramvara tillsammans med data från praktiska mätningar så testades olika förändringar i anläggningen. Studien resulterade i förslag på en höjning av frysrumstemperaturen och temperaturen i LTB1. Dessa åtgärder höjer anläggningens köldfaktor och minskar energibehovet. Förslag för att få bukt på istillväxten är att isolera av komponenter så som rör och ventiler. Isolering ger en energibesparing och en minskad risk för korrosion. Genom belastningstester framkom det att kompressorerna arbetar ofördelaktigt så förslag på lämpliga driftområden togs fram för att öka verkningsgraden och minska underhållskostnaderna och energibehovet. Anläggningen visade sig vara väl dimensionerad mot transmissionsförluster men att golvvärmen står för en oproportionerligt stor del av förlusterna i förhållande till dess yta. / The study is conducted for Freezing Food Småland Öland AB. The purpose of the study was to propose measures to decrease the facility’s energy demand and to calculate the payback time for these suggestions. By means of using simulation software along with data from practical measurements different configurations in the facility were tested. The study resulted in suggestions consisting of an increase of the temperature in the freezing room and the temperature in LTB1.Those suggestions increases the facilities COP and decreases the energy consumption. Proposals to curb the ice growth are the insulation of components such as pipes and valves. Insulation results in a small decrease in energy demand but greatly increases the accessibility and also decreases the risk of corrosion. Through load tests conducted on the compressors it showed that the compressors were not driven in the optimal load range, suggestions were made for operation in a more favourable load range. Thus increasing the efficiency and cutting the maintenance costs. From the results it is shown that the facility is well built and dimensioned against thermal transmission. Though it turned out that the floor heating accounts for a disproportionate amount of the thermal transmission.