We present a vision for 4G cellular networks based on the concept of autonomous infrastructure deployment. Cellular base stations, or femtocell access points, are deployed by network users without being constrained by the conventional cell planning process from the network operator. Autonomous deployment allows the network to grow in an organic manner which requires new methods for spectrum management. We study a framework for autonomous network optimization based on the method of cognitive interference management. In our model, a number of femtocells are co-channel deployed in an underlay macrocellular network. Instead of fully reusing 100% of the macrocellular resource, partial reuse is cognitively determined in femtocells based on their individual network environment. According to an interference signature perceived from the environment, a femtocell autonomously determines the appropriate channel allocation and minimizes the network interference. Upon the cognitive acquisition of the random infrastructure topology, base station pilot power is autonomously configured in order to maximize the cellular coverage. A series of network self-configuration procedures are discussed for automatic cell size adaptation and resource management. Our results show that the new approaches based on cognitive radio configuration facilitate the network optimization in terms of interference management, mobile handoff, pilot power control and network resource allocation. The proposed framework offers a 4G vision for spectrum management in an autonomous self-managed cellular architecture.

We present a vision for 4G cellular networks based on the concept of autonomous infrastructure deployment. Cellular base stations, or femtocell access points, are deployed by network users without being constrained by the conventional cell planning process from the network operator. Autonomous deployment allows the network to grow in an organic manner which requires new methods for spectrum management. We study a framework for autonomous network optimization based on the method of cognitive interference management. In our model, a number of femtocells are co-channel deployed in an underlay macrocellular network. Instead of fully reusing 100% of the macrocellular resource, partial reuse is cognitively determined in femtocells based on their individual network environment. According to an interference signature perceived from the environment, a femtocell autonomously determines the appropriate channel allocation and minimizes the network interference. Upon the cognitive acquisition of the random infrastructure topology, base station pilot power is autonomously configured in order to maximize the cellular coverage. A series of network self-configuration procedures are discussed for automatic cell size adaptation and resource management. Our results show that the new approaches based on cognitive radio configuration facilitate the network optimization in terms of interference management, mobile handoff, pilot power control and network resource allocation. The proposed framework offers a 4G vision for spectrum management in an autonomous self-managed cellular architecture.

In Europe, the prices of natural gas and electricity reached an all-time high during 2022. An approach tomitigate these high prices is to expand the district heating systems in urban areas, this will reduceelectric load as well as to increase the power production in combined heat and power plants. Districtheating has been the dominant heat supply technology in urban areas in Sweden since the 1980s.However, as the number of low energy buildings are increasing, district heating distribution losses mustbe reduced to ensure cost-efficient consumer demand supply. This has led to the idea of the 4th-generation district heating which is characterized by low distribution temperatures.The aim of this study is to simulate low temperature distribution systems in a planned future city districtusing a Python based simulation tool and compare the results with a conventional system. Threedifferent types of low temperature distribution systems are investigated: 1) domestic hot water andspace heating separated, 2) apartment heat exchangers, 3) a cascading low temperature system.Focus is on simulating the distribution losses, distribution temperature and mass flow in the area, butthe scope of the analysis also includes an investigation of the effect of lower return temperatures to thecombine heat and power plant. The result indicate which type of system is most beneficial to implementin this specific area.With regards of distribution losses and temperature drop performs the low temperature distributionsystem with apartment heat exchangers better than the cascading system and the system withdomestic hot water and space heating separated. The mass flow is highly dependent of the temperaturedemand in the heating systems in the buildings and is higher for all low temperature distributionsystems compared to a conventional system.

4th generation district heating (4GDH) and varying the indoor temperature to store heat are both important concepts that can make it easier to implement more renewable energy and reduce costs of heating. This study looks at these concepts from a customer perspective using one building and looking at how energy can be stored and the performance of 4GDH. Low temperature heat sources from industry, supermarkets, and datacentres are used in combination with heat from a combined heat and power plant to get the required heating. A heat pump has also been modelled as a part of the 4GDH structure. In addition to looking at heat storage in 4GDH a scenario with direct electric heating has also been evaluated. In conclusion 4GDH has lower operating costs than 3rd generation district heating, but it is not worth varying the indoor temperature to store energy when using 4GDH. It is, however, profitable to vary indoor temperature if direct electric heating is used.

Thermal energy storage (TES) systems are technologies with the potential to enhance the efficiency and the flexibility of the coming 4th generation low temperature district heating (LTDH). Their integration would enable the creation of smarter, more efficient networks, benefiting both the utilities and the end consumers. This study aims at developing a comparative assessment of TES systems, both latent and sensible heat based. First, a techno-economic analysis of several TES systems is conducted to evaluate their suitability to be integrated into LTDH. Then, potential scenarios of TES integration are proposed and analysed in a case study of an active LTDH network. This is complemented with a review of current DH legislation focused on the Swedish case, with the aim of taking into consideration the present situation, and changes that may support some technologies over others. The results of the analysis show that sensible heat storage is still preferred to latent heat when coupled with LTDH: the cost per kWh stored is still 15% higher, at least, for latent heat in systems below 5MWh of storage size; though, they require just half of the volume. However, it is expected that the cost of latent heat storage systems will decline in the future, making them more competitive. From a system perspective, the introduction of TES systems into the network results in an increase in flexibility leading to lower heat production costs by load shifting. It is achieved by running the production units with lower marginal heat production costs for longer periods and with higher efficiency, and thus reducing the operating hours of the other more expensive operating units during peak load conditions. In the case study, savings in the magnitude of 0.5k EUR/year are achieved through this operational strategy, with an investment cost of 2k EUR to purchase a water tank. These results may also be extended to the case when heat generation is replaced by renewable, intermittent energy sources; thus increasing profits, reducing fuel consumption, and consequently emissions. This study represents a step forward in the development of a more efficient DH system through the integration of TES, which will play a crucial role in future smart energy system. / Thermal energy storage (TES) eller Termisk energilagring är en teknologi med potentialen att öka effektivitet och flexibilitet i den kommande fjärde generationens fjärrvärme (LTDH). Studien har som mål att kartlägga en komparativ uppskattning av TES systemen, baserad både på latent och sensibel värme. Resultaten visar att lagring av sensibel värme är att föredra före latent värme när den kopplas med LTDH: pris per lagrade kWh kvarstår som 15% högre än för latent värme i system under 5 MWh av lagringsutrymme; dock fordrar de endast hälften av volymen. Utifrån systemperspektiv innebär introduktionen av TES system i nätverket en ökning av flexibilitet vilket leder till reducerade värmeproduktionskostnaderna i mindre belastning. I fallstudien nås en sparnivå av femhundra euro per år genom denna operativa strategi, med en investering av 2000 euro för inköp av vattentank. Resultaten kan också vidgas till en situation där värmeproduktionen ersätts av förnybara, intermittenta energikällor; till detta medföljer högre vinster, lägre bruk av bränsle vilket skulle innebära lägre utsläpp. Studien kan ses som ett steg framåt mot skapandet av en mer effektiv DH system genom integrationen av TES, vilket kommer att spela en betydande roll i framtida smarta energisystem.

Heat production together with electricity production stands for 31% of the global CO2 emissions. The production is as of today still highly dependent on fossil fuels, with a global district energy mix share of fossil fuels of 90%. To stay in line with the Paris Agreement, district heating must be configured away from fossil fuels by utilizing new emission free heat sources as well as creating higher energy efficient cities by incorporating more waste heat recovery. Helsinki has a District Heating (DH) dominated by fossil fuels and proclaimed goals of becoming carbon-­neutral by 2035, as of 2020 the annual heat demand in the city was 6.4TWh of heat. To do so, there is a need for research to investigate ways to include carbon-­free heat sources into the current heating system. There is currently a limited amount of literature available in this area and from the identified research gap the following main research question was developed. How can Helsinki achieve carbon-­free district heating? To easier answer the main research question, three three sub­questions were developed. (1) How large is the energy potential for non­-carbon based heat sources in Helsinki for district heating? (2) Where are the heat sources located? (3) What are the techno-­economic implications of the heat sources? A high resolution heat source mapping and spatial analysis was conducted for the city of Helsinki where low grade heat sources were to be identified for the purpose of district heating. The work focused on the following heat sources: Grocery Retail, Ice Rinks, Subway Stations, Data Centers, Wastewater, Sea Water Heat Pumps and Geothermal Energy. The developed model consists of five steps: (1) Heat source identification, (2) Technical potential evaluation, (3) DH-network mapping & Spatial analysis, (4) Economic model, and (5) Techno-­Economic evaluation. A total of 363 heat source points was identified and evaluated. The combined results of the heat sources were a total capacity of 1257.56 MW with a resulting total annual heat production of 7008.31 GWh. The majority of the capacity and heat was contributed from seawater heat pumps and geothermal heat pumps. Around 84% of the mapped heat sources were within 100 meters of the current district heating piping network. The economical findings show that a majority of the heat sources yield a positive net present value and a discounted payback period of below 11 years. The levelized cost of heat was within reasonable expectations when compared to existing data where Data centers showed the most promising result. The study can conclude that Helsinki can potentially achieve a non-­carbon­ based district heating system with a sufficient heat production management strategy. / Värme­- och elproduktionen står tillsammans för 31% av de globala koldioxidutsläppen. Produktionen är idag fortfarande starkt beroende av fossila bränslen med en global andel fossila bränslen i fjärrvärmeblandningen på 90%. För att hålla sig i linje med Parisavtalet måste fjärrvärmen konfigureras bort från fossila bränslen genom att utnyttja nya utsläppsfria värmekällor samt skapa mer energieffektiva städer genom att utnyttja mer återvinning av spillvärme. Helsingfors har en fjärrvärme som domineras av fossila bränslen och har utsatt mål om att bli koldioxidneutralt senast 2035, vid 2020 hade staden en årlig värmekonsumption på 6.4 TWh. För att uppnå detta behövs forskning för att undersöka hur man kan inkludera koldioxidfria värmekällor i det nuvarande värmesystemet. Det finns för närvarande bristfällig mängd litteratur på detta område och utifrån den identifierade forskningsluckan utvecklades följande huvudsakliga forskningsfråga. Hur kan Helsingfors uppnå koldioxidfri fjärrvärme? För att lättare kunna besvara huvudfrågan utvecklades tre underfrågor. (1) Hur stor är energipotentialen för icke kolbaserade värmekällori Helsingfors för fjärrvärme? (2) Var finns värmekällorna? (3) Vilka är de tekno-­ekonomiska konsekvenserna av värmekällorna? En högupplöst kartläggning av värmekällor och en rumslig analys genomfördes för Helsingfors stad där lågkvalitativa värmekällor skulle identifieras för fjärrvärme. Arbetet fokuserade på följande värmekällor: Livsmedelsbutiker, isbanor, tunnelbanestationer, datacenter, avloppsvatten, värmepumpar för havsvatten och geotermisk energi. Den utvecklade modellen består av fem steg: (1) Identifiering av värmekällor, (2) Utvärdering av teknisk potential, (3) Kartläggning av DH­-nätverk och rumslig analys, (4) Ekonomisk modell och (5) Teknisk-ekonomisk utvärdering. Totalt 363 värmekällor identifierades och utvärderades. De kombinerade resultaten av värmekällorna var en total kapacitet på 1,257.56 MW med en total årlig värmeproduktion på 7,088.31 GWh. Merparten av kapaciteten och värmen kom från havsvattenvärmepumpar och geotermisk värme. Cirka 84% av de kartlagda värmekällorna låg inom 100 meter från det nuvarande fjärrvärmerörnätet. De ekonomiska resultaten visar att majoriteten av värmekällorna gav ett positivt nettonuvärde och en diskonterad återbetalningstid på mindre än 11 år. Den standardiserade kostnaden för värme låg inom rimliga gränser när den jämförs med befintliga data, där datacenter visade det mest lovande resultatet. Givet studiens resultat kan slutsatsen erhållas att Helsingfors potentiellt kan uppnå ett fossilfritt fjärrvärmesystem med en tillräcklig produktions-­ och värmehanteringsstrategi för fjärrvärme.

The world is constantly striving towards a more sustainable living, where every part of contribution is greatly appreciated. When it comes to heating of buildings, district heating is often the main source of heat. During specific times, peak demands are created by the tenants who are demanding a lot of heat at the same time. This demand peak puts a high load on the piping system as well as the need for certain peak boilers that run on non-environmental friendly peak fuel. One solution that is presented in this degree project that solves the time difference between production and demand is by utilizing thermal storage solutions. A dynamic district heated building model is developed with proper heat propagation in the pipelines, thermal inertia in the building and heat losses through the walls of the building. This is all done utilizing 4th generation district heating temperatures. Modelica is the tool that was used to simulate different scenarios, where the preheating of indoor temperature is done to mitigate the possibility for demand peaks. Using an already existing model, implementation and adjustments are done to simulate thermal storage and investigate its effectiveness in a 4th generation district heating system. The results show that short-term energy storage is a viable solution in concrete buildings due to high building mass. However, combining both 4th generation district heating with storage in thermal mass is shown not to be suitable due to low temperatures of supply water, which is not able to increase the temperature of the building’s mass enough.

Das Standardmodell einer zusätzlichen sequentiellen Fermiongeneration (SM4) war 2012 auf Basis eines Fits an elektroschwache Präzisionsobservable und die Higgs-Signalstärken mit einer Signifikanz von 5.3 sigma ausgeschlossen worden. Komplementär dazu wurden in der vorliegenden Arbeit Fits des SM4 an eine Kombination eines typischen Satzes von Flavour-Observablen mit den Ergebnissen des zuvor durchgeführten Elektroschwachen Präzisionsfits durchgeführt. Im SM3-Kontext extrahierte Größen wurden gemäß ihrer Bedeutung im SM4 reinterpretiert und die angepassten theoretischen Ausdrücke angegeben. Die resultierenden Einschränkungen der CKM-Matrix des SM4, ihrer potentiell CP-verletzenden Phasen sowie der Masse des up-type-Quarks der 4. Generation t'' werden angegeben. Zum Vergleich des SM4 mit dem SM3 werden die erreichten chi^2-Werte genutzt. chi^2=15.53 im SM4 und 9.56 im SM3 passen fast vollkommen zu einer gleich guten Beschreibung der Experimente durch beide Modelle, wobei das SM3 aber sechs Freiheitsgrade mehr besitzt. Außerdem wurden die Vorhersagen des SM3 und des SM4 für die Dimyon-Ladungsasymmetrie ASL mit experimentellen Werten verglichen. Die Vorhersage des SM3 ist ca. 2 sigma vom experimentellen Wert entfernt, die des SM4 ca. 3 sigma.\par Die Ergebnisse deuten nicht darauf hin, dass die Signifikanz des 2012 erreichten Ausschlusses des SM4 durch die Hinzunahme von Flavour-Observablen zu den damals verwendeten elektroschwachen Präzisionsobservablen und Higgs-Querschnitten bedeutend verringert würde.\par Es konnte jedoch keine genaue quantitative Aussage über die Auswirkungen der Flavourobservablen auf diese Signifikanz getroffen werden, weil das Programm CKMfitter likelihood-ratio-Berechnung nur durchführen kann, wenn sich eines der untersuchten Modelle durch Fixierung von Parametern aus dem anderen ergibt (nested models), was hier nicht der Fall ist. / The Standard Model extended by an additional sequential generation of Dirac fermions (SM4) was excluded with a significance of 5.3 sigma in 2012. This was achieved in a combined fit of the SM4 to Electroweak Precision Observables and signal strengths of the Higgs boson. This thesis complements this excludion by a fit of the SM4 to a typical set of Flavour physics observables and the results of the previously performed Electroweak Precision fit. Quantities extracted in an SM3 framework are reinterpreted in SM4 terms and the adapted theoretical expressions are given. The resultant constraints on the SM4''s CKM matrix, its potentially CP-violating phases and the mass of the new up-type quark t'' are given. To compare the relative performance of the SM4 and the SM3, this work uses the chi^2 values achieved in the fit. The values of 15.53 for the SM4 and 9.56 for the SM4 are almost perfectly consistent with both models describing the experimental data equally well with the SM3 having six degrees of freedom more. The dimuon charge asymmetry ASL was not used as a fit input because the interpretation of its measurement was subject to debate at the time when the fits were produced, but its prediction in the fit was used as an additional test of the SM4. The SM3''s prediction differs from the experimental values by about 2 sigma, and the SM4''s prediction by about 3 sigma. \par In summary, these results do not suggest that any significant reduction of the 5.3 sigma exclusion could be achieved by combining the Electroweak Precision Observables and Higgs inputs with Flavour physics data. However, the exact effect of the Flavour physics input on the significance of the SM4''s exclusion cannot be given at this point because the CKMfitter software is currently not able to perform a statistically stringent likelihood comparison of non-nested models.