Magistro baigiamasis darbas "Lietuvos energetikos ūkio administravimas“ parašytas Annos Tatarnikovos, vadovaujant viešojo administravimo katedros profesoriui dr. Vladimirui Obrazcovui. Pasirinktos temos aktualumas tame, jog Lietuvos šilumos ūkis dar vystymosi stadijoje ir tinkamai įvertinus esamą energetikos ūkio administravimo patirtį galima pakeisti bei įtakoti šilumos sektoriaus ateitį. Darbo naujumą ir praktinį reikšmingumą sudaro tai, jog greta teorinės ir praktinės analizės, bus atliekamas ir Lietuvos šilumos ūkio administravimo efektyvumo tyrimas. Būtina akcentuoti, jog pokyčiai energetikos sektoriuje neišvengiami, pasitelkus kvalifikuotus šios srities specialistus, remiantis moksliniais tyrimais, atlikus atitinkančią realiai padėčiai SWOT analizę galima užtikrinti sklandžią šilumos ūkio veiklą bei skaidrų finansinių išteklių panaudojimą. Darbe analizuojant mokslinę literatūrą pateikiamos kapitalo pritraukimo alternatyvos šilumos ūkio modernizavimui. Pagrindinės alternatyvos yra: banko kreditai, įmonės koncesija-nuoma, dalinis įmonės privatizavimas. Siūlomos ir kitos alternatyvos: paslaugų sutartis ir administravimo sutartis, tačiau jų galiojimo terminas daug trumpesnis ir jos gali būti panaudotos tik kaip laikinos priemonės. Darbe naudojami istorinis ir lyginamasis tyrimo metodai naudojami ištirti šilumos ūkio administravimo raidą Lietuvoje, bei jai darančius įtaką veiksnius, restruktūrizavus šilumos ūkį. Apibendrinant rezultatus, teikiant rekomendacijas... [to full text] / Actuality of the chosen topic is in the fact that the Lithuanian heating network is going under development. Having estimated the existing administration experience correctly, one can change or influence upon the heating sectors future. The novelty and practical meaning of the work consists in the research of the effectiveness of the Lithuanian heating system administration to be performed, alongside with the theoretical and practical analysis. The accent is put upon the inevitability of changes in the energy sector. The changes are inevitable if being deeply investigated by researchers and scientific specialists doing profound SWOT analysis to reinforce the heating system activities using transparent financial sources. The scientific literature has been analyzed concerning (alternative) capital investments alternatives for heating systems modernization. The main alternatives are: bank credits, concession companies rentals and privatization of companies. The other alternatives are: service argument; administration agreement. However, the validity term of such services is by for shorter, so they com serve as temporary means alone. Summarizing the results the method of analytical criticism has been used. AB “Vilniaus energija” the Vilnius energy sector of the beginning of 2002 has been analysed. This company signed a rental concession agreement with a foreign society. To find out the advantages and disadvantages of the heating system rentals to the private sector, the... [to full text]

The European Union’s ambitious climate targets necessitate substantial reductions in greenhouse gas emissions, particularly within the heating and cooling sector, which accounts for a significant portion of energy consumption. District Heating and Cooling (DHC) systems emerge as a key solution for decarbonizing this sector by enabling high efficiency heat production and the integration of renewable and carbon-neutral energy sources. Despite the potential inherent in DHC systems, their utilization is limited, partly due to challenges associated with network topology selection. This master’s thesis addresses the optimization of District Heating Network layout expansion while tackling these challenges. Situated within the framework of an European funded project coordinated by EIFER, the research aims to develop an algorithm for modeling and planning the expansion of DHN networks, considering geographical location of pipes and heat production and consumption nodes. Building upon the Automatic Network Drawing Algorithm (ANDA) tool provided by EIFER, the project seeks to enhance it to generate expansion scenarios incorporating loops, a feature critical for network robustness absent in the current output. The tool pandapipes is used for fluid system modeling, effectively modelinghydraulics and heat through network elements such as heat producer, substationsand pipes. The algorithm’s core feature is to strategically determine optimallocations along initial tree-like network expansions to incorporate loops. Variousheuristic approaches are tested to identify the most efficient expansion strategies,subsequently adding new lines to minimize total costs, encompassing both capitaland operational expenses. Real-world data from a District Heating Network inMilan validate the algorithm’s capabilities. / Europeiska unionens ambitiösa klimatmål kräver avsevärda minskningar av utsläppen av växthusgaser, särskilt inom värme- och kylsektorn, som står för en betydande del av energiförbrukningen. Fjärrvärme- och fjärrkylasystem (DHC) framstår som en nyckellösning för att minska koldioxidutsläppen i denna sektor genom att möjliggöra högeffektiv värmeproduktion och integrering av förnybara och koldioxidneutrala energikällor. Trots potentialen som finns i DHC-system är deras användning begränsad, delvis på grund av utmaningar i samband med val av nätverkstopologi. Denna masteruppsats behandlar optimering av utbyggnaden av fjärrvärmenätets layout samtidigt som man tacklar dessa utmaningar. Beläget inom ramen för ett europeiskt finansierat projekt koordinerat av EIFER, syftar forskningen till att utveckla en algoritm för modellering och planering av utbyggnaden av DHN-nät, med hänsyn till den geografiska placeringen av rör och värmeproduktions- och förbrukningsnoder. Med utgångspunkt i verktyget Automatic Network Drawing Algorithm (ANDA) från EIFER, försöker projektet förbättra det för att generera expansionsscenarier med slingor, en funktion som är avgörande för nätverkets robusthet som saknas i den aktuella utgången. Verktyget pandapipes används för modellering av vätskesystem, effektiv modellering av hydraulik och värme genom nätverkselement som värmeproducent, transformatorstationer och rör. Algoritmens kärnfunktion är att strategiskt bestämma optimala platser längs initiala trädliknande nätverksutbyggnader för att införliva slingor. Olika heuristiska tillvägagångssätt testas för att identifiera de mest effektiva expansionsstrategierna, och sedan läggas till nya linjer för att minimera de totala kostnaderna, som omfattar både kapital- och driftskostnader. Verkliga data från ett fjärrvärmenätverk i Milano validerar algoritmens kapacitet.

The construction of the Southeast city district in Uppsala will start in 2025 with plans to be completed in 2050. When a new district is built, there is an opportunity to explore the best possible solution to all the needs of the city, one of the needs that must be met is the heat demand of all buildings. One possible way to meet these needs is through district heating. The aim of this report is to design and investigate the efficiency of a heat distribution network in the Southeast city district by determining its distribution losses and the requirements that heating distribution networks must fulfill. The method used to satisfy the purpose is to simulate the systems through a model in Python. The model produces key parameters such as distribution losses, pressure drop and temperature drop during high heat demand and low heat demand. The results of the report shows what a possible distribution network design could look like for two stages of construction. It is also shown that during low heat demand, the highest distribution losses were in the return pipe. During the high heat demand, the highest distribution losses were in the supply pipe. This is also the period of the greatest mass flow rate, temperature drop and pressure drop. The discussion addresses the correlation between these parameters as well as exploring how connecting an additional building stage impacts the performance of the system. The conclusions of this paper is that the designed distribution networks fulfill the necessary criteria for pressure, temperature and energy delivery with acceptable distribution losses. When a additional stage is connected to the system, distribution losses do not increase significantly, making the model suitable for future extensions of district heating networks.

Subject of this thesis is district heating and heating network model design. Firstly, it de-scribes basic principles of heat supply and its elements. Secondly, computational model of heating network is created based on grid map of the network. The model contains proposed pipeline system and calculation of heat and pressure losses. Lastly, price map for heat con-sumption points, in dependence on heat losses, is presented.

This thesis deal with design and implementation of innovative cooling method, intended primarily for medium-power synchronous generators. The main objective of this proposal is to remove the large heat exchanger connected to generator. This heat exchanger unduly increases the space requirements for the machine location. The proposed solution is to use a direct water-cooled stator. It is assumed that the rotor winding will be still cooled by air. Unlike current cooling system, the hot air from the rotor can be cooled in smaller cooler inside the generator. In this work are described methods which can be used for design of water cooling basic parameters, taking required temperatures into account. A small induction motor was selected for practical verification of the proposed cooling concept. This motor was modified into two variants - related to the old cooling of synchronous generators and related to the proposed solution. Both of these variants were measured and compared with each other. Subsequently, CFD models of these two variants were set up. Measured temperatures were used for debugging of models and identification of material properties of components of these machines. The final model of water-cooled variant also makes it possible to simulate the work of motor for higher performance and to determine the overload compared with the old cooling variant. Some knowledge and experience obtained from the small water-cooled induction machine were used in the design of water-cooling for large synchronous generator. In a similar way, CFD models of the old variant of cooling and proposed variant of water- cooling were created. Although these models were not verified by actual measurements on the generators, the results indicated that the application of water-cooling in this type of machine is appropriate and provides many benefits.

I Sverige är fjärrvärme den vanligaste uppvärmningsformen. Vatten värms upp i en fjärrvärmeanläggning och distribueras genom nedgrävda rör i marken, också kallat fjärrvärmenätet. En tillförlitlig energimodell anses vara ett bra och viktigt hjälpmedel för analyser av värmeförluster som uppstår i ett fjärrvärmenät vid distribueringen av det heta vattnet. Sandviken Energis styrning av framledningstemperaturen sker idag utifrån en inställd styrkurva som tar hänsyn till vad det är för utetemperatur. Det var av intresse för studien att jämföra denna styrning med en simulerad framledningstemperatur och identifiera övertemperaturer i Sandviken Energis fjärrvärmenät i Sandviken. Detta gjordes utifrån att undersöka hur olika faktorer påverkade värmebehovet. De påverkande faktorer som studerats i detta examensarbete var följande: utetemperatur, månad, tid på dygnet och vindhastighet. Mätdata gällande valda påverkande faktorer hämtades för perioderna 2015 till och med 2019, analyserades och indelades för att se deras påverkan på värmelasten. Utifrån indelningen av faktorerna utvanns ekvationer från deras effektkurvors trendlinjer. Ekvationerna användes för att skapa en simuleringsmatris för styrningen. En egenskapad masterekvation simulerade den ideala styrningen utifrån simuleringsmatrisen och de krav på påverkande faktorer som ställs av ett exempel-år. Den ideala styrningen beräknades om till en ideal framledningstemperatur och jämfördes därefter med den verkliga framledningstemperaturen. Tillsammans med en värmeförlustsimulering i NetSim, som resulterade i vad sparad energi per grad är värd, kunde besparingspotentialen beräknas. Resultatet visar på att en besparingspotential på 261 MWh är möjlig att uppnå vid en sänkning av framledningstemperaturen för att utesluta övertemperaturer i fjärrvärmenätet, vilket är en minskning med ca 1,8 % jämfört med det verkliga året. Detta skulle motsvara en besparing på ca 70 000 SEK genom en förändring av styrningen. En minskad framledningstemperatur kommer påverka resten av systemet positivt, bland annat för att returtemperaturen kommer minska, rökgaskondenseringens och pannornas effektivitet öka samt minskade utsläpp i form av bland annat CO2, för att nämna några exempel. / In Sweden district heating is the most common form of heating. Water is heated in a district heating plant and distributed through buried pipelines in the ground, also called the district heating network. A reliable energy model is considered to be a good and important tool for analysis of heat losses that occur in a district heating network when the hot water is distributed. Sandviken Energi’s control of the supply temperature is based today on a set control curve that takes into account what the outdoor temperature is. It was of interest to this study to compare this control with a simulated supply temperature and identify overtemperatures in Sandviken Energi’s district heating network in Sandviken. This was done on the basis of examining how different factors affected the heat demand. The influencing factors studied in the thesis were the following: outdoor temperature, month, time of day and wind speed. Measurement data on selected influencing factors were collected for the periods 2015 through 2019, analyzed and subdivided to see their effect on the heat load. From the subdivision of the factors, equations were extracted from the trend lines of their effect curves. The equations were used to create a simulations matrix for the control. A custom master equation simulated the ideal control based on the simulation matrix and the demands on influencing factors set by an example year. The ideal control was recalculated to an ideal supply temperature and then compared with the actual supply temperature. Together with a heat loss simulation in NetSim, which resulted in what energy saved per degree is worth, the savings potential could be calculated. The result shows that a saving potential of 261 MWh is possible to achieve by lowering the supply temperature to exclude excess temperatures in the district heating network, which is a decrease of about 1.8 % compared to the real year. This would correspond to a savings of about 70 000 SEK through a change in control. A reduced supply temperature will have a positive impact on the rest of the system, including reducing the return temperature, increasing the efficiency of flue gas condensation and boilers, and reducing emissions such as CO2, to name a few examples.

The purpose of this report is to get an overview of the CO2 reduction possibilities when adopting different renewable energy source, when the case studied building sustains a district heating network connection and when not, and how the renewable energy source flexibilities (Solar and Wind) differ depending on region. The method regards a ETC house that falls into the climate positive category and assesses the reduction when comparing CO2 emissions form the energy demand. The result for the flexibilities is then compared to the BBR demand. The result shows a difference of around 10% in production for the flexibilities when comparing the northern and middle region with the southern. And a decrease between 19-36% gCO2. Comparing a scenario with and without a connection to the district heating network showed that when the ground source heat pump offsets the energy demand, CO2, and cost reductions (6 and 4% respectively) can be seen. With an average installation cost, the payback period for the ground source heat pump can be estimated to be around 4 year. In conclusion the thesis project shows that the climate is a ruling factor when assessing energy questions for the residential sector. It also shows the difference in CO2 and cost that comes with it can be reduced and help mitigated the sectors effects on the environment. This in turn shows that the overall reduction of CO2 for the case studied building follows the demands and goals set by the European commission and gives motivation to expand the construction as cost is also reduced.

This thesis deal with design and implementation of innovative cooling method, intended primarily for medium-power synchronous generators. The main objective of this proposal is to remove the large heat exchanger connected to generator. This heat exchanger unduly increases the space requirements for the machine location. The proposed solution is to use a direct water-cooled stator. It is assumed that the rotor winding will be still cooled by air. Unlike current cooling system, the hot air from the rotor can be cooled in smaller cooler inside the generator. In this work are described methods which can be used for design of water cooling basic parameters, taking required temperatures into account. A small induction motor was selected for practical verification of the proposed cooling concept. This motor was modified into two variants - related to the old cooling of synchronous generators and related to the proposed solution. Both of these variants were measured and compared with each other. Subsequently, CFD models of these two variants were set up. Measured temperatures were used for debugging of models and identification of material properties of components of these machines. The final model of water-cooled variant also makes it possible to simulate the work of motor for higher performance and to determine the overload compared with the old cooling variant. Some knowledge and experience obtained from the small water-cooled induction machine were used in the design of water-cooling for large synchronous generator. In a similar way, CFD models of the old variant of cooling and proposed variant of water- cooling were created. Although these models were not verified by actual measurements on the generators, the results indicated that the application of water-cooling in this type of machine is appropriate and provides many benefits.

The pulp and paper industry is the most energy intensive industry in Sweden. Most of the energy usedaims to supply the large amount of heat to the production processes that is required to produce pulp andpaper . By increasing the energy efficiency of paper mills, there is great potential to reduce productioncosts and reduce its environmental impact. This project involves mapping, analyzing and investigation ofmeasures that can contribute to increased thermal efficiency of an internal heating network at Holmen’spaper mill, Braviken. The heating network, called VVG, utilises excess heat from the pulp and paperproduction and supplies heat to production processes and premises at the factory. When the heat demandof the VVG-system exceeds the available recovered heat, heat from live steam is transferred. This projectaim at identifying measures with potential to reduce demand of live steam supply. The project started bymapping the entire VVG-system to identify which consumers are included and how it is connected. Thenthe consumers were studied and data was collected to determine their power and energy demands. Basedon the mapping and collected data, proposals for measures that have the potential to increase thermalenergy efficiency were noted which in turn can reduce the need for live steam supply. The measures havebeen focused on reducing the return temperature of the VVG-system and reducing the heat demand of thesystem. Reduced return temperatures are achieved by more efficient use of the existing heat flow. Thisleads to increased heat recovery potential which means that more excess heat can be utilised.The proposed measures that were identified as having potential to contribute to reduction of the returntemperatures of the VVG-system are as follow: • Utilising return flows with high flow rates and high temperatures to provide other consumers inVVG with heat. This allows the hot flow to be used instead of going directly into the return line. • Eliminate short circuits in the system where the supply line goes directly into the return line. Thesewere detected in the forms of three-way valves and flows through consumers that were not running. The proposed measures that have been identified as having the potential to contribute to reduction of theheating demand of the VVG are as follows: • Turning off flows passing through consumers that are not in use to reduce unnecessary temperaturedrops which will result in decreased power losses. • Preheating via residual flows at consumers where raw water tempered circuits is heated. As theraw water is cold during large parts of the year, a lot of heat can be saved by preheating it with aflow of lower energy quality than VVG. • Shut down the VVG flow through heat exchangers in the heat recovery system when the heatrecovery process not are running to avoid negative heat transfer. By implementing these measures, large improvements regarding the thermal efficiency of the VVG-system can be achieved at Holmen Paper Braviken. How much the return temperatures decrease and howmuch the heat recovery potential increases with the proposed measures has not been quantified during thisproject. However, the measures aimed at lowering the heat demand in the VVG-system can be quantifiedto contribute to an predicted energy saving of at least 2.8 GWh annually, but the investigations of themeasures indicates that significantly larger energy savings can be achieved. To ensure the potential of theproposed measures to contribute to the reduction of the demand for live steam supply, Holmen needs tocarry out further studies of the VVG system where this work is intended to form the basis for their furtherwork.

Fjärrvärmen utgör omkring hälften av all uppvärmning som sker i Sverige idag och har utöver det en viktig roll då den tar vara på mycket energi som annars hade gått till spillo. Att kunna vara ekonomiskt konkurrenskraftig gentemot andra uppvärmningsalternativ är en viktig del för fjärrvärmens fortsatta utveckling. Det finns flera alternativ och möjligheter att göra detta, ett av dem är att hålla nere driftkostnaderna. Det kan bland annat göras genom att minska tryckfallen i näten, som även kan ge en ökad expansionsmöjlighet. Idag används främst avstängningsventiler med reducerande genomlopp i näten, främst på grund av den billigare investeringen. Trots detta saknas en kunskap om hur dessa ventiler påverkar näten sett till tryckfall, drift- och investeringskostnader jämfört med ventiler med fullt genomlopp. För att undersöka detta har två metoder använts för att komplettera varandra och öka förståelsen för ventilerna. Den första metoden beräknade det generella fallet teoretiskt för att se vid vilka flöden som ventiler med fullt genomlopp är mer gynnsamma. Den andra metoden beräknade ett specifikt fall med simuleringar i ett verkligt nät med de olika ventilerna och beräkna vilken som är den mest ekonomiskt gynnsamma. Resultaten av det generella fallet visar att ventiler med fullt genomlopp blir mer gynnsamma när flödeshastigheten överstiger omkring 1 m/s, oavsett dimension, beräknat på under 30 år med ett elpris på 1,50 kr/kWh. Vid dimensionering av nät är det vanligt att använda 1,5 - 2,0 m/s, detta utgör ofta en liten del av nätets drifttid och är ofta lägre. Beräkning av det specifika fallet visade att ventiler med reducerande genomlopp är det ekonomiska alternativet då återbetalningstiden för ventiler med fullt genomlopp var över 600 år vid 1,50 kr/kWh. Utifrån detta kan slutsatsen dras att ventiler med fullt genomlopp inte bör ersätta reducerande genomlopp, utan att det i stället handlar om att identifiera de delar i nätet som utgör, eller kan komma att utgöra, en strypning eller förträngning i nätet där höga flödeshastigheter kan förekomma och möjligtvis byta till fullt genomlopp. / District heating makes up about half of all heating that takes place in Sweden today and, in addition to that, has an important role as it makes use of a lot of energy that would otherwise have been wasted. Being able to be economically competitive against other heating alternatives is an important part of the continued development of district heating. There are several options to do this, one of which is to keep operating costs down. This can be done by reducing the pressure drops in the networks, which can also provide an increased possibility of expansion. Today, shut-off valves with reducing throughput are mainly used in networks, often because of the cheaper investment. Despite this, there is a lack of knowledge about how these valves affect the networks, which is attributed to pressure drop, operating and investment costs compared to valves with full flow. To investigate this, two methods have been used to complement each other and increase the understanding of the valves. In the first method, the general case is calculated theoretically to see at which flows valves with full flow are advantageous. The second method calculates a specific case with simulations in a real network with the different valves and calculates which one is the most economically advantageous. The results of the general case show that valves with full flow become more advantageous when the flow rate exceeds about 1 m/s, regardless of dimension, calculated over 30 years with an electricity price of SEK 1.50 /kWh. When dimensioning networks, 1.5 - 2.0 m/s is a common value, this often constitutes a small part of the network's operating time and is often lower. Calculation of the specific case showed that valves with reducing throughput are the economic alternative as the payback period for valves with full throughput was over 600 years at SEK 1.50/kWh. Based on this, the conclusion can be drawn that valves with full throughput should not replace reducing throughput, but that it is instead a question of identifying the parts of the network that constitute a throttling or constriction in the network where high flow rates can occur and possibly switch to valves with full throughput.