One initiative to reduce greenhouse gas (GHG) emissions involves developing standards for GHG inventories. Companies and cities (regions) can use GHG inventories to compile and report their GHG emissions. Standards for corporate and city GHG inventories often claim that GHG inventories can be used for identifying emissions opportunities, building reduction strategies and setting, measuring and reporting emissions targets. Attributional emissions factors are generally used in corporate and city GHG inventories. For purchased electricity, heat and steam, this means using average emission factors for regional or national production of each energy carrier. Also contractual emissions factors can be used. Changes in emissions from affected production elsewhere are not included. For purchased electricity and district heating (DH), a GHG inventory can be improved by lowered purchases or by purchasing a different energy carrier. Furthermore, combined heat and power (CHP) technology can help reduce global GHG emissions in the supply and conversion of energy, as CHP production is more efficient than conventional separate production of electricity and heat. In CHP production, excess heat from electricity production is utilised for heating buildings, hot water, industry processes etc., either directly or through DH systems. This thesis analyses how emissions reduction measures based on corporate or city GHG inventories, carried out using GHG Protocol standards, affect global CO2 emissions when electricity or CHP-based DH is affected. The incentive of a GHG inventory to a company purchasing electricity and DH, and to a city regarding purchases and production of electricity and DH in its region, is analysed. This is done for GHG inventories conducted in a nation where electricity produced within the nation is regarded as CO2-lean (Sweden) and in a nation where it is more CO2-rich (Germany). The indirect incentive to the DH company to change its production, in order to improve the GHG inventory of its customers and of the city where the DH system is located, is also analysed. Consequential analyses are used to assess how global CO2 emissions are affected by changes in purchases or production of electricity and DH that are incentivised by the GHG inventories studied. These consequential analyses include changes in emissions from affected electricity production elsewhere. The results show that the strength of incentive to reduce purchase of electricity or CHP-based DH by a company or in a city can differ between GHG inventories and consequential analysis. This is most clear when electricity produced within the nation is regarded as CO2-lean (Sweden) while affected electricity production elsewhere is CO2-rich. For replacing purchases of CHP-based DH with electricity, or vice versa, the incentive in a GHG inventory can be the reverse of that in a consequential analysis. Moreover, the incentive to lower the use of electricity is lost when contractual emissions factors with zero emissions, such as renewable electricity guarantees of origin (RE-GOs), are used. In addition, purchase of electricity RE-GOs, which have a large surplus and no requirement of additionality, is less likely to cause a corresponding increase in production of renewable electricity. Furthermore, when the highest emission reduction per Euro invested is sought (e.g. when investment resources are limited), the investment ranking of a heat-only boiler and a CHP plant can differ depending on whether the focus is on improving a city GHG inventory or lowering global CO2 emissions. Moreover, if the DH company improves (reduces) the average emissions factor for DH, it improves the GHG inventory of its customers and of the city where they are located. In a DH system based on bio-fuelled CHP production, the average emissions factor for DH improves when CHP electricity production is lowered to the extent that production of heat at the oil-fuelled heat-only boiler (used for peak heat production) is minimised. However, according to consequential analysis, this would lead to an increase in global CO2 emissions. Based on the results of this thesis, it is concluded that measures which include changes in purchases or production of electricity or CHP-based DH can increase global CO2 emissions when based on how corporate or city GHG inventories in general value CO2 emissions of electricity and DH. It is therefore unfortunate that GHG Protocol standards for corporate and city GHG inventories advocate basing emissions reduction decisions on GHG inventories. There is nonetheless an obvious risk of reported and communicated GHG inventories being used as a basis for emissions reductions decisions. If the aim is actual reduction of global CO2 emissions, average or purchased emissions factors should not be used for purchased electricity and CHP-based DH when assessing, reporting or communicating the impact of companies and cities (regions) on CO2 emissions. Instead, a consequential approach should be used for climate evaluation of purchased electricity and DH. / Ett av många initiativ för att minska utsläpp av klimatpåverkande gaser är framtagandet av regelverk för klimatredovisningar. Klimatredovisningarna kan användas av företag och städer (regioner) för att sammanställa och rapportera om företagets eller stadens utsläpp av klimatpåverkande gaser. I regelverken för framtagande av klimatredovisningarna betonas ofta att klimatredovisningen kan användas för att identifiera var utsläppsminskningar kan göras, att utveckla strategier för att minska klimatpåverkande utsläpp samt för att sätta, mäta och följa upp mål för klimatpåverkande utsläpp. En klimatredovisning innehåller vanligtvis bokföringsvärden, vilket innebär att lokala genomsnittliga utsläppsfaktorer används för köpt el och värme. Även köpta utsläppsfaktorer kan användas. Klimatredovisningen inkluderar inte ändringar i utsläpp från produktion som påverkas någon annanstans. En klimatredovisning kan förbättras t ex genom att mindre energi köps eller genom byte av energibärare. För el- och värmeförsörjning kan kraftvärmeteknik bidra till minskade globala utsläpp av koldioxid (CO2), eftersom kraftvärmeproduktion är mer effektivt än separat produktion av el och värme. Vid kraftvärmeproduktion tas överskottsvärmen från elproduktionen tillvara för att värma byggnader, varmvatten, industriprocesser mm, antingen direkt eller via fjärrvärmesystem. I denna avhandling analyseras hur globala utsläpp av CO2 påverkas av åtgärder som påverkar förbrukning eller produktion av el och fjärrvärme, när beslut om sådana åtgärder baseras på ett företags eller en stads klimatredovisning, gjorda enligt Greenhouse Gas Protocols regelverk. Incitamenten i ett el- och fjärrvärmeköpande företags klimatredovisning och i en stads klimatredovisning analyseras. Detta görs för klimatredovisningar utförda i ett land där elproduktionen inom landet är CO2-mager (Sverige) och ett land med mer CO2-rik elproduktion (Tyskland). Dessutom analyseras de indirekta incitament som dessa klimatredovisningar ger till det lokala fjärrvärmeföretaget att ändra sin produktion för att förbättra sina kunders klimatredovisningar och klimatredovisningen för staden där fjärrvärmeverksamheten finns. Konsekvensanalyser görs för att beräkna hur olika åtgärder som stödjs av klimatredovisningarna påverkar globala CO2-utsläpp. I konsekvensanalyserna inkluderas också förändringar i utsläpp från påverkad elproduktion, även om den förändringen sker någon annan stans. Resultaten visar att styrkan i incitamentet att minska ett företags eller en stads inköp av el eller fjärrvärme kan skilja sig mellan en klimatredovisning och en konsekvensanalys. Detta är särskilt tydligt när klimatredovisningen görs i ett land där elproduktionen inom landet är CO2-mager (Sverige) medan den påverkade elproduktionen är CO2-rik. När det gäller utbyte av fjärrvärme mot el eller tvärtom kan en klimatredovisning ge motsatta incitament jämfört med den ledningen en konsekvensanalys ger. När köpta emissionsfaktorer med nollutsläpp för el används, t ex förnybara ursprungsgarantier, försvinner incitamentet att minska elanvändningen. Det är dessutom mindre sannolikt att ett köp av förnybara ursprungsgarantier för el medför motsvarande ökning av produktion av förnybar el, då överskottet av förnybara ursprungsgarantier för el är stort och additionalitetskrav saknas. När investeringsresurser är begränsade kan det vara av intresse att utvärdera vilken investering som ger mest reduktion av klimatpåverkande gaser per investering. Avhandlingens resultat visar att investering i hetvattenproduktion och kraftvärmeproduktion då kan komma att sinsemellan rangordnas olika, beroende på om målet är att förbättra stadens klimatbokslut eller om målet är att minska globala utsläpp av CO2. Om fjärrvärmeföretaget förbättrar (minskar) genomsnittlig emissionsfaktor för sin fjärrvärme, förbättras klimatbokslutet för deras kunder och för staden där fjärrvärmesystemet är beläget. Resultaten visar också att i ett fjärrvärmesystem, som baseras på ett bioeldat kraftvärmeverk och där olja används för efterfrågetoppar när det är som allra kallast, förbättras fjärrvärmens emissionsfaktor när elproduktionen i kraftvärmeverket minskas. Dock visar konsekvensanalysen att ett sådant agerande kan medföra ökade globala utsläpp av CO2. Baserat på resultaten dras slutsatsen att beslut om åtgärder, som påverkar köp eller produktion av el eller kraftvärmebaserad fjärrvärme, kan orsaka ökning av globala CO2-utsläpp om de baseras på de incitament ett klimatbokslut ger. Det är därför olyckligt att GHG Protocols regelverk för företags och städers klimatbokslut rekommenderar att klimatboksluten används för beslut som avser att minska utsläpp av CO2. Även om de inte rekommenderade detta, finns ändå en uppenbar risk att rapporterade och kommunicerade klimatbokslut används som bas för beslut om åtgärder som syftar till minskade utsläpp av CO2. Om syftet är minskade globala CO2-utsläpp bör genomsnittliga och köpta emissionsfaktorer inte användas för klimatvärdering av köpt el och kraftvärmebaserad fjärrvärme när ett företags eller en stads (regions) klimatpåverkan beräknas, rapporteras eller kommuniceras. För klimatvärdering av köpt el och fjärrvärme bör i stället en konsekvensbaserad metod användas.

This thesis looked at a biorefinery pilot plant that converted lignin in black liquor into biofuel. A heat/mass balance was made which was used to create a heat/mass balance for a theoretical large-scale plant. This then created the CAPEX for building the plant. OPEX for the largescale plant and income from sold biofuels was calculated and payback time found. This was done for three different cases with different flows and yield to optimize the plant. A sensitivity analysis was then made to find the most important parameters regarding CAPEX, OPEX and payback time.

CO2 separation plays an important role to mitigate the CO2 emissions due to burning of fossil fuels, and it is also of importance in biofuel production (e.g. biogas upgrading and bio-syngas purification and conditioning). The solvent-based absorption is the state-of-art technology for CO2 separation, where various solvents, e.g. amine solutions, Selexol (i.e. dimethyl ethers of polyethylene glycol), and propylene carbonate, have been introduced. However, these solvent-based technologies meet challenges such as high solvent degradation, high corrosion rate to equipment, high construction cost, high energy demand for solvent regeneration and high solvent make-up rate. Therefore, the development of novel solvents to overcome the challenges of the currently available solvents is essential. Recently, ionic liquids (ILs) have gained great interest as new potential solvents for CO2 separation, mainly due to their very low vapor pressure and relatively high CO2 solubility. In addition, ILs have lower corrosive characteristic, lower degradation rate and lower energy requirement for solvent regeneration compared with the conventional organic solvents. However, the main challenge of the application of ILs is their higher viscosity than the conventional solvents, which can be solved by adding co-solvents such as water. The overall objective of this thesis work was to develop low-cost IL based technologies for CO2 separation. To achieve this objective, the deep eutectic solvent (DES) of choline chloride (ChCl)/Urea with molar ratio 1:2 as a new type of IL was selected as an absorbent and H2O was used as co-solvent for CO2 separation from biogas. The conceptual process was developed and simulated based on Aspen Plus, and the effect of water content on the performance of ChCl/Urea for CO2 separation was evaluated. It was found that the optimal proportion of aqueous ChCl/Urea was around 50 wt% (percentage by weight) of water with the lowest energy usage and environmental effect. The performance of aqueous ChCl/Urea was further compared with the commercial organic solvents in this thesis work. The rate-based process simulation was carried out to compare the energy usage and the cost for CO2 separation from biogas. It was found that aqueous ChCl/Urea achieved the lowest cost and energy usage compared with other commercial solvents except propylene carbonate. The performance comparison proved that CO2 solubility, selectivity and viscosity were three important parameters which can be used as criteria in the development of novel physical solvents for CO2 separation. ILs with acetate anions normally show high CO2 solubility and selectivity, and the ILs with alkylmorpholinium as cations have low toxicity leading to lower environmental effect. Therefore, in this thesis work, a series of N-alkyl-N-methylmorpholinium-based ILs with acetate as counterpart anion were investigated, and water was added as co-solvent to adjust the viscosity. The CO2 solubility in these aqueous ILs was measured at different temperatures and pressures. It was found that the increase of alkyl chain length in the cation led to an increase of CO2 solubility of the ILs with the same anion. Aqueous N-butyl-N-methylmorpholinium acetate ([Bmmorp][OAc]) had the highest CO2 solubility, and it was selected to further carry out thermodynamic modeling and process simulation. The energy usage and the size of equipment of using aqueous [Bmmorp][OAc], aqueous ChCl/Urea, water, Selexol, and propylene carbonate for CO2 separation from biogas were compared. It was found that this novel IL mixing with water had better performance, that is, with lower energy usage and smaller size of equipment than the other solvents. This result suggests that using this aqueous [Bmmorp][OAc] has the potential to decrease the cost of CO2 separation.

No description available.

<p>This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened.</p><p> </p><p>I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator. The purpose for that was to open the valve if the temperature dropped more than one degree inside. With the help of a program called IDA it was calculated that, if the temperature drop five degrees, they would have sixteen hours at the heating power plant to open the flow before the sensor open the valves.</p><p> </p><p>After careful consideration I came up with the conclusion that the wireless network must be the best solution. Mostly because you can monitor all the clients in the system from the heating power plant and that will make it easier to discover faults and temperature differences.</p><p>Wireless networks is already a well tested solution in form of wireless controlled electricity meters so it shouldn’t be to much of a problem connecting these sensors to it either.</p>

<p>This thesis presents a study of the cooling process of a solid block performed by a turbulent air flow channel. The study focuses on the turbulent flow and its influence in the heat transfer of the block.</p><p>The first part of the thesis is an analysis of the different turbulent model and their adaptation on the necessities of this study. Once the turbulent model has been confirmed it makes a study of the behavior of the cooling process by CFD (Computational Fluid Dynamics), and an analysis of the numerical accuracy of this computational study.</p><p>When the procedure of the study of the cooling process is defined it proposes some different variations in the initial solution to improve this process. The study concentrates in variations of the turbulence and the geometry of the studied block.</p><p>Finally, the different improving are discussed analyzing parameters as the heat transfer, pressure drop, time consuming or energy consuming.</p>

<p>This project has been developed at the company Gavlegardarna. The companyowns a large part of the buildings of Gävle and two of them are the objective ofthe project. Gavlegardana is highly concerned about the environment; for thisreason, they cooperate on the subject with the energy management from theirtechnical department.</p><p>Gävle is one of the Swedish cities where the DH (district heating) network isdistributed, arriving to most of the dwellings, industries and commercialbuildings. As DH uses environmentally friendly sources of energy,Gavlegardana is introducing it in its buildings.</p><p>Electrical radiators and boilers were installed in the buildings when the price ofelectricity was more affordable than nowadays. The price of the electricity canbe considered 1,23 SEK/kWh while the DH price is 0,45 SEK/kWh.</p><p>Consequently, this is another reason why the objective of the company at thepresent time is to replace electrical space heating systems by means of districtheating.</p><p>The energy balance of the buildings is analysed in order to study their currentenergy situation. This entails the consideration of heat gains and lossesinvolved. The heat gains of the building are the heat from solar radiation whicharrives at the building trough the windows, the heat internally generated (bypersons, lighting and other devices) and the heat supplied. The heat losses are composed by the transmission trough walls and windows, the infiltrations, the heat used for hot tap water and the ventilation losses.</p><p>An important part of the work required to calculate the energy balance hasconsisted of the collection and organization of all the data (areas, types ofmaterial, electrical devices, lighting, number of employees, opening hours...).This data comes from the drawings of the buildings provided by the companyand from the information gathered during the visits to the installation. In addition, the ventilation flows were measured in-situ using the tools provided by Theorells.</p><p>Gavle Energi, the DH distributor company, has been contacted in order to fixthe cost and other details related to the district heating connection. The heatexchanger models, selected from Palmat System AB, are TP20 for Building Aand TP10 for Building B. TP20 provides 100 kW of heating and 0,4 l/s of hot tap water and TP10 provides 50 kW and 0,31 l/s respectively. The capital cost is 187500 SEK which includes the heat exchangers and the connection cost.</p><p>As the secondary circuit is not currently installed because the existing system iscomposed by electrical radiators, the installation of the piping network in thebuilding has been designed. The radiators’ power is calculated taking intoaccount the need of heat in each room which is estimated as the transmissionlosses. This need of heat calculated is higher than the energy currently supplied which means that the thermal comfort is not achieved in all the rooms of the buildings.</p><p>In spite of using more energy for space heating, the change of heat sourceentails a lower energy cost per year. The selected radiators are from Epeconand the investment cost (including the installation) is 203671 SEK. The brand of the selected pipes is Broson and the investment cost of the total piping system is 66000 SEK.</p><p>The initial investment of the new installation is 457171 SEK, considering the DHconnection, heat exchangers, radiators and pipes. If the initial investment istotally paid in cash by the company the payback will be fulfilled in 6 years. Incase of borrowing the money from the bank (considering an interest rate of 5%), two possibilities can be considered: paying back the money in annual rates over 15 years or 30 years of maturity. The paybacks are 11 and 8 years respectively.</p><p>After designing the DH piping system in the buildings, estimating the total costs of the investment and studying the project’s feasibility by suggesting different payment options, some possible energy savings are recommended.</p><p> </p><p>The first of the options refers to the transmission losses trough the windowswhose values’ are considerably high. Using a glass with a lower U-value, theselosses can decrease until 66% (with triple glass windows). Consequently, thepower required for space heating can also be reduced until 26%.</p><p>Regarding the ventilation, rotating heat exchangers are currently used, whichentails the problem of smells mixture detected by the users of the buildings. By changing them with flat-plate heat exchangers, the problem is solved and the efficiency is increased from 66% to 85%. The new heat exchanger cost is340387 SEK and it has a payback of 10 years.</p>

This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened.   I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator. The purpose for that was to open the valve if the temperature dropped more than one degree inside. With the help of a program called IDA it was calculated that, if the temperature drop five degrees, they would have sixteen hours at the heating power plant to open the flow before the sensor open the valves.   After careful consideration I came up with the conclusion that the wireless network must be the best solution. Mostly because you can monitor all the clients in the system from the heating power plant and that will make it easier to discover faults and temperature differences. Wireless networks is already a well tested solution in form of wireless controlled electricity meters so it shouldn’t be to much of a problem connecting these sensors to it either.

This project has been developed at the company Gavlegardarna. The companyowns a large part of the buildings of Gävle and two of them are the objective ofthe project. Gavlegardana is highly concerned about the environment; for thisreason, they cooperate on the subject with the energy management from theirtechnical department. Gävle is one of the Swedish cities where the DH (district heating) network isdistributed, arriving to most of the dwellings, industries and commercialbuildings. As DH uses environmentally friendly sources of energy,Gavlegardana is introducing it in its buildings. Electrical radiators and boilers were installed in the buildings when the price ofelectricity was more affordable than nowadays. The price of the electricity canbe considered 1,23 SEK/kWh while the DH price is 0,45 SEK/kWh. Consequently, this is another reason why the objective of the company at thepresent time is to replace electrical space heating systems by means of districtheating. The energy balance of the buildings is analysed in order to study their currentenergy situation. This entails the consideration of heat gains and lossesinvolved. The heat gains of the building are the heat from solar radiation whicharrives at the building trough the windows, the heat internally generated (bypersons, lighting and other devices) and the heat supplied. The heat losses are composed by the transmission trough walls and windows, the infiltrations, the heat used for hot tap water and the ventilation losses. An important part of the work required to calculate the energy balance hasconsisted of the collection and organization of all the data (areas, types ofmaterial, electrical devices, lighting, number of employees, opening hours...).This data comes from the drawings of the buildings provided by the companyand from the information gathered during the visits to the installation. In addition, the ventilation flows were measured in-situ using the tools provided by Theorells. Gavle Energi, the DH distributor company, has been contacted in order to fixthe cost and other details related to the district heating connection. The heatexchanger models, selected from Palmat System AB, are TP20 for Building Aand TP10 for Building B. TP20 provides 100 kW of heating and 0,4 l/s of hot tap water and TP10 provides 50 kW and 0,31 l/s respectively. The capital cost is 187500 SEK which includes the heat exchangers and the connection cost. As the secondary circuit is not currently installed because the existing system iscomposed by electrical radiators, the installation of the piping network in thebuilding has been designed. The radiators’ power is calculated taking intoaccount the need of heat in each room which is estimated as the transmissionlosses. This need of heat calculated is higher than the energy currently supplied which means that the thermal comfort is not achieved in all the rooms of the buildings. In spite of using more energy for space heating, the change of heat sourceentails a lower energy cost per year. The selected radiators are from Epeconand the investment cost (including the installation) is 203671 SEK. The brand of the selected pipes is Broson and the investment cost of the total piping system is 66000 SEK. The initial investment of the new installation is 457171 SEK, considering the DHconnection, heat exchangers, radiators and pipes. If the initial investment istotally paid in cash by the company the payback will be fulfilled in 6 years. Incase of borrowing the money from the bank (considering an interest rate of 5%), two possibilities can be considered: paying back the money in annual rates over 15 years or 30 years of maturity. The paybacks are 11 and 8 years respectively. After designing the DH piping system in the buildings, estimating the total costs of the investment and studying the project’s feasibility by suggesting different payment options, some possible energy savings are recommended.   The first of the options refers to the transmission losses trough the windowswhose values’ are considerably high. Using a glass with a lower U-value, theselosses can decrease until 66% (with triple glass windows). Consequently, thepower required for space heating can also be reduced until 26%. Regarding the ventilation, rotating heat exchangers are currently used, whichentails the problem of smells mixture detected by the users of the buildings. By changing them with flat-plate heat exchangers, the problem is solved and the efficiency is increased from 66% to 85%. The new heat exchanger cost is340387 SEK and it has a payback of 10 years.

<p> Various environmental and economic factors have lead to increased global investment in alternative energy technologies such as solar and wind power. Although methodologies for synchronous generator control are well researched, wind turbines present control systems challenges not presented by traditional generation. The varying nature of wind makes achieving synchronism with the existing electrical power grid a greater challenge. Departing from early use of induction machines, permanent magnet synchronous generators have become the focus of power systems and control systems research into wind energy systems. This is due to their self excited nature, along with their high power density. The problem of grid synchronism is alleviated through the use of high performance power electronic converters. In achievement of the optimal levels of efficiency, advanced control systems techniques oer promise over more traditional approaches. Research into sliding mode control, and linear matrix inequalities with nite time boundedness and H&infin; performance criteria, when applied to the dynamical models of the system, demonstrate the potential of these control methodologies as future avenues for achieving higher levels of performance and eciency in wind energy.</p>