• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 63
  • 5
  • Tagged with
  • 68
  • 43
  • 37
  • 35
  • 32
  • 20
  • 15
  • 12
  • 12
  • 10
  • 8
  • 8
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Energiutredning på Chips AB, Åland / Energy Analysis at Chips AB, Åland

Renström, Thom, Sundbäck, Henrik January 2013 (has links)
En energikartläggning har gjorts hos Chips AB för att undersöka hur energin fördelas över de olika produktionslinjerna. Energianvändningen från processer som är gemensamma för alla produktionslinjer har också undersökts. Energianvändningen för dessa har fördelats över pro- duktionslinjerna eftersom produkterna även ska bära upp dessa energikostnader. Där det vi- sade sig att chipslinjen använder överlägset mest energi under ett år, 13 200 MWh, men den linjen körs mest också. Näst störst energianvändning hade moslinjen som bara låg på 6 600 MWh. När energianvändningen beräknades per producerat kilogram visade det sig att det var moslinjen som använder mest energi, 2,75 kWh/kg. Från energianvändningen beräknades kostnad och koldioxidutsläpp, både totalt och per pro- ducerat kilogram. Här visade det sig att moslinjen även har högst koldioxidutsläpp och högst kostnad per producerat kilogram. Chipslinjen har näst högst koldioxidutsläpp per producerat kilogram, men det är de friterade produkterna från PF2-linjen som har näst högst kostnad per producerat kilogram. Det beror på att det är olja som används till fritösen i PF2-linjen. Flera åtgärdsförslag för att minska energianvändningen har tagits fram. Det var två skorstenar som hade mycket överskottsvärme som kan användas, chipsfritösen och PF1-fritösen. De bästa förslagen skulle vara att använda denna överskottsvärme till uppvärmning av lokaler och tappvarmvatten samt uppvärmning av blanchörvatten. Tillsammans skulle detta i bästa fall kunna ge en årsbesparing på ungefär 516 000 € och ändå ha en återbetalningstid under ett år. Andra åtgärdsförslag som också undersöktes var förvärmning av luften till chipspannan, absorptionskyla och elproduktion, men dessa förslag hade mindre besparingspotential och längre återbetalningstid än det första förslagen. / An energy analysis has been made at Chips AB to investigate how the energy is distributed over the various production lines. Energy from processes common to all production lines have also been investigated. Energy use for these have been distributed over the production lines since the products also should carry these energy costs. There, it is shown that the potato chips line is using by far the most energy in a year, 13,200 MWh, but it is the line that runs the most too. The potato mash line had the second largest energy use, at 6,600 MWh. But when the energy usage was calculated per kilogram produced, it turned out that it was the potato mash line that use the most energy, 2.75 kWh/kg. From the total energy use the cost and carbon emissions were calculated, both in total and per produced kilogram. Here it showed that the potato mash line also has the highest emissions of carbon dioxide and the highest energy cost per kilogram produced. It is also the potato chips line that has the second highest emissions of carbon dioxide per kilogram produced, but it is the fried products from the PF2 line that has the second highest energy cost per kilogram pro- duced. This is because the fryer in the PF2 line uses oil to heat up the frying oil. Several proposed measures to reduce energy use have been developed. Three of the chimneys that were measured at Chips AB had a lot of excess heat that can be used, it was the potato chips fryer, the PF1 boiler and the PF1 fryer. The best proposed measures is to use the excess heat for space heating and domestic hot water and to heat the blanching water. Together, these measures could at best be able to provide an annual saving of approximately € 516,000, and still have a payback period of less than a year. Other proposed measures that also were inves- tigated were preheating of the air to the potato chips boiler, absorption cooling and power generation, but these proposals had less savings and longer payback periods than the first pro- posals.
12

Värme från gruvvatten : En undersökning av olika metoder för att kunna hämta värme ur vattnet som pumpas upp ur gruvorna / HEAT FROM MINE WATER : An investigation of different methods to be able to retrieve heat from the water that is pumped up from the mines

Mathilda, Glas January 2023 (has links)
Boliden Mineral AB - Boliden Mines is a company that carries out continuous improvement work in the energy and environmental area. During this degree project, the possibility of making use of waste heat from the mine water that is pumped out of the Renström mine was evaluated. The possibility of making use of the heat from the mine water is interesting as the water that is pumped up maintains a stable temperature between +8 degrees to +20 degrees. This provides a suitable heat source for heat pumps by extracting the heat using heat exchangers or collectors. The purpose of this thesis has been to investigate which type of solution between collectors and heat exchangers is technically and economically most advantageous. The cases reviewed are to either invest in components for the existing heat pump, which is located next to the collection basin, in the old treatment plant, or to invest in a new facility in connection with the fire dam. Reviews to determine alternative collectors and heat exchangers were carried out on a theoretical basis. The review was based on the fact that collectors and heat exchangers must be durable, easy to disassemble and easy to maintain. Through economic analyzes and discussion with various companies and suppliers, three different collectors and three different heat exchangers respectively were determined as possible solutions. Conclusions were extracted from these components for the various cases. The conclusion that can be drawn for the existing case of the existing heat pump located adjacent to the collection pond, the old treatment plant, is that an installation of two Geek kooil collectors is the most economically beneficial investment. The company also chose to invest in this option.For the case of a new facility in connection with the fire dam, the result is presented depending on the investment in the number of heat pumps, where the payback times vary between the different investment options. The payback time of the collectors and heat exchangers varies between 3 to 8 years depending on the number of heat pumps or collectors.Conclusion given from both the existing case and the case of a new plant gave that from the point of view of the collectors, the Geek kooil collector was the better option, both for the existing heat pump and for a new installation of one, two or three heat pumps. A Geek kooil collector gave an investment cost per kW between SEK 3813 and 2647/kW. For the heat exchangers, the plate heat exchanger from Alfa laval was determined to be the better option for a new installation of both one, two or three heat pumps. The plate heat exchanger from Alfa laval gave an investment per kW of SEK 360/kW, which is lower than the comparative alternatives.
13

Energieffektivisering i flerbostadshus : Undersökning av lönsamheten med energieffektivare ventilation

Jonsson, Reine January 2009 (has links)
<p>This thesis is based on a case study for the real estate manager Mimer in Västerås. Mimer provides a great deal of this city’s rental apartments. Many of their buildings have ventilation systems with a type of heat-recovery called “heatpipe”. This case study focuses on two buildings which have certain problems with these heatpipes. The recovery rates of the existing systems are low, and one building suffers from a warm indoor climate in the summertime. Problems with the indoor climate seem to stem from a faulty installation of the heatpipe. This building does also have considerably higher energy consumption than the other one, which leads suspicions to overloaded fan motors.</p><p> </p><p>The main purpose of this study is to retrieve information about the present situation energy- and ecomonywise. A new type of heat recovery and new fans has been chosen by Mimer in order to calculate expected new energy consumption for these buildings. These values will lead to a few LCC calculations which show life cycle costs for the existing systems and the new systems. Based on the LCC calculations one or more options will be chosen as a recommended action for the ventilation systems. The recommendations will be analysed and discussed from different point of views that are relevant for a real estate manager.</p>
14

Energieffektivisering i flerbostadshus : Undersökning av lönsamheten med energieffektivare ventilation

Jonsson, Reine January 2009 (has links)
This thesis is based on a case study for the real estate manager Mimer in Västerås. Mimer provides a great deal of this city’s rental apartments. Many of their buildings have ventilation systems with a type of heat-recovery called “heatpipe”. This case study focuses on two buildings which have certain problems with these heatpipes. The recovery rates of the existing systems are low, and one building suffers from a warm indoor climate in the summertime. Problems with the indoor climate seem to stem from a faulty installation of the heatpipe. This building does also have considerably higher energy consumption than the other one, which leads suspicions to overloaded fan motors.   The main purpose of this study is to retrieve information about the present situation energy- and ecomonywise. A new type of heat recovery and new fans has been chosen by Mimer in order to calculate expected new energy consumption for these buildings. These values will lead to a few LCC calculations which show life cycle costs for the existing systems and the new systems. Based on the LCC calculations one or more options will be chosen as a recommended action for the ventilation systems. The recommendations will be analysed and discussed from different point of views that are relevant for a real estate manager.
15

Rakrörshantering / Tube Handling

Heinemo, Marcus, Bäckström, Carl January 2011 (has links)
In the current situation is the straight tube cutter, that provides Luvata’s line of large recoolers with copper tubes, manually operated. To prevent damages and facilitate mounting the tubes must be properly arranged when they leave the machine. This report aims to investigate and present an automated solution where the operator does not need to participate in the process. A number of theories have been drawn up and tests have been done. The results show that the in principle best solution is to have a leaning carrier that’s automatically height-adjusted by two lift tables underneath. The height adjustment keeps a constant distance between the top tube layer and rollover protection bars on the machine. That is done to allow the carrier to have a high enough angle to ensure that the tubes roll down even if they aren’t completely straight, but without rolling over the previous tubes. To evaluate the solutions Ulrich and Eppingers method for Concept scoring was used. This method means that the various solutions are scored and weighted based on a number of criteria’s, and the output is measurable results.
16

Beräkningsalgoritm för fouling i pelletervärmeväxlare inom plasttillverkning

Marouf, Tawga January 2015 (has links)
Sweden’s energy consumption is divided into three major sectors. One of them is the industry sector. One third of Sweden’s energy consumption is converted in the industries. The chemical industry is one of those industries with great energy needs. This thesis looks into energy efficiency in industry, in particular the plastics manufacturing industry. Efficiency concerning heat exchangers, their fouling resistance and also pumps. This thesis also relates to the industry in the big picture as heat exchangers and pumps are widely used and these has a great energy and environmental efficiency. This thesis presents an algorithm especially developed for this issue. The thesis has been written by dividing the work into measurements and data, implementation and analysis. The result of this thesis is an Excel-sheet that may be used to calculate the fouling resistance in a plate heat exchanger. / Sveriges energianvändning är uppdelad i tre stora sektorer. Ett av dem är industrin. En tredjedel av Sveriges energiförbrukning omvandlas inom industrierna. Kemiindustrin är av dem industrier som har stort energibehov. Detta examensarbete tar upp effektivisering inom industrin, närmre sett plasttillverkningsindustrin. Effektiviseringen berör värmeväxlare och dess foulingresistans och även pumpar. Examensarbetet kan spegla industrin i den stora bilden då värmeväxlare och pumpar finns väldigt utspritt och effektiviseras dessa har en stor energi och miljöeffektivisering gjorts. För att energieffektivisera inom detta examensarbete har en beräkningsalgoritm tagits fram. Arbetet har delats upp i mätvärden, beräkningar genomförande och analys. Resultatet blev en Excel-ark som kan användas för att beräkna foulingresistansen i en plattvärmeväxlare.
17

Frostskyddsreglering i batterivärmeväxlare : Utvärdering av värmeväxlare av modell Ecoterm och Econet / Frost protection control in run-around coil heat exchangers : Evalutaion of heat exchanger models Ecoterm and Econet

Granlund, Alexander January 2018 (has links)
Detta examensarbete är utfört i samarbete med Fläkt Woods i syfte att utvärdera frostskyddsregleringen i deras äldre och nyare modeller av batterivärmeväxlare, Ecoterm respektive Econet. Ecoterms frostskydd regleras efter temperaturen på vätskekretsen medan det för Econet även regleras utifrån frånluftens daggpunktstemperatur för att förhindra onödig aktivering av frostskyddet. Ecotermsfrostskydd består främst av shuntreglering av vätskeflödet medan Econet först reglerar vätskeflödet innan shuntreglering påbörjas. Utvärderingen baseras på mätningar utförda vid Norrlands Universitetssjukhus, NUS, under främst februari 2018, varav den lägsta temperaturen uppmätt för uteluften var -23°C. För Ecoterm, som regleras utifrån en vätsketemperatur på -5°C, påbörjas shuntreglering vid en uteluftstemperatur på cirka -14°C, oavsett om det finns risk för frostbildning eller inte. Under mätperioden fanns det aldrig risk för frostbildning i Ecoterm när frostskyddet aktiverats. För Econet är resultaten tvetydiga, men antyder att shuntreglering endast använts vid två tillfällen under hela mätperioden. Detta beror till viss del på designen av Econet, som har spetsvärme integrerad på värmeväxlarens vätskekrets.Resultaten från Ecoterm visar ett tydligt behov av den moderna frostskyddsregleringensom används i Econet, för kvantifierbara jämförelser krävs dock vidare studier. / This master’s thesis was written in collaboration with Fläkt Woods in order to evaluate the frost protection control of two run-around coil heat exchangers, their older model Ecoterm and their newer model Econet. The frost protection of Ecoterm is only reliant on the temperature of the liquid circuit whereas Econet also regards the dewpoint temperature of the exhaust air, as to not activate the frostprotection unnecessarily. Ecoterm uses bypass control for frost protection and defrosting whereas Econet first increases the liquid flowrate before initiating bypass control. The evalutation is built upon data collected from the university hospital in Umeå, NUS, mainly during february 2018, with a minimum outside temperature of -23°C. Ecoterm starts defrosting when the liquid temperature reaches -5°C, which correlates to an outside temperature of -14°C irregardless if there is any risk of frost growth, which there was not during the measuring period. For Econet the results were more difficult to interpret, but imply that bypass control only was nescessary at two occasions during the whole measuring period. This is partly due to the design of Econet, which integrates the additional heating, normally reserved for a separate battery, into the heat exchangers liquid circuit. The results for Ecoterm show the limitations of single parameter controlled frost protection and why better frost protection control is necessary for highly efficient heat exchangers. For quantifiable results further studies are required.
18

Inkopplingsalternativ för frånluftsvärmepumpar : Analys av flerbostadshus i Kungälv

Svanqvist, Christian January 2018 (has links)
Sverige har målsättningen att sänka energianvändningen med 20 % till 2020 och för att lyckas med det behöver bland annat bostadssektorn dra sitt strå till stacken. Sedan miljonprojektet finns det ett stort antal flerfamiljshus med hög energikonsumtion och ett sätt att minska den är att installera frånluftsvärmepump. I det för projektet aktuella fallet ägs huset av kommunen som också äger fjärrvärmenätet som huset är anslutet till. Vid installation av frånluftsvärmepumpar i kombination med fjärrvärme kan problem med förhöjd returtemperatur till fjärrvärmenätet uppstå. Projektets mål har varit att identifiera besparingspotentialen hos olika installationsalternativ och att se hur de påverkar returtemperaturen till fjärrvärmenätet. Med simuleringar har fastslagits att den största besparingspotentialen finns när frånluftsvärmepumpen får arbeta mot uppvärmning av radiatorvattnet samt momentan uppvärmning av tappvattnet. Denna inkoppling leder också till god avkylning. Bäst avkylning leder dock en liknande inkoppling men med värmelager för tappvattnet. Känslighetsanalysen gör gällande att en höjning av elpriset ger en viss försämring av besparingen och en höjd framledningstemperatur från frånluftsvärmepumpen gör också att besparingen minskar. En sänkning av framledningstemperaturen för radiatorkretsen leder till en ganska stor ökning av besparingen.
19

Värmeåtervinning ur spillvattensystem / Heat recovery from wastewater system

Lindström, Ida, Nyrén, Alexander January 2023 (has links)
Byggnadssektorn stod år 2020 för 21% av Sveriges totala utsläpp av koldioxidekvivalenter men har sedan 2019 minskat till följd av minskade utsläpp från el- och fjärrvärmesektorn. Genom kloka system- och materialval vid ombyggnation och projektering kan byggnadssektorn energieffektiviseras och den totala miljöpåverkan därmed minska. Energiförluster som uppstår i byggnader kan idag till viss del återvinnas genom exempelvis värmeåtervinningsaggregat för ventilation samt genom att göra byggnadskonstruktionen mer tät för minskade transmissionsförluster. Genom att även rikta fokus mot tapp- och spillvattensystemet kan den varmvattenenergi som spolas bort också tas tillvara genom värmeväxlare för spillvatten. Syftet med detta projekt har varit att teoretiskt undersöka lönsamheten kring installation utav värmeväxlare för spillvatten på stående avloppsstammar i byggnaden Glesvingen samt vilka faktorer som påverkar lönsamheten mest. För att åstadkomma detta har en beräkningsmodell skapats utifrån befintliga data som sedan lagt grunden till specifika teoretiska energiberäkningar för Glesvingen. Även indata från Bostäder i Borås har hämtats gällande temperaturer respektive kall- och varmvattenmängder. För att få en bild kring hur lönsamheten ser ut har olika lönsamhetskalkyler även genomförts. I resultatet presenteras hur återvunnen energimängd påverkas av antalet spillvattenstammar i byggnaden samt spillvattenflödets temperatur. Resultatet visar även hur energibesparingen ser ut när varma och kalla spillvattenflöden separeras. Gällande lönsamhetsberäkningarna presenteras jämförelser för kostnad, besparing och resulterande besparing sett över 50 respektive 25 år för 21 stammar. Avslutningsvis presenteras en sammanställning av olika lönsamhetskalkyler för Glesvingen vid olika förutsättningar. Gällande installation av värmeväxlare i Glesvingen anses denna investering ej vara lönsam för aktuell byggnadsutformning. / In 2020, the construction sector accounted for 21% of Sweden’s total emissions of carbon dioxide equivalents but has since 2019 decreased as result of reduced emissions from the electricity and district heating sector. By making smart choices regarding systems and material when rebuilding and project planning could the construction sector be made more energy efficient and the total environmental impact may be reduced. Energy losses that occur in buildings today may be recovered to some extent with for example heat recovery units for ventilation and by sealing the building structure better. Hot water energy that is flushed away can be utilized trough heat exchangers for wastewater in order to recover heat from the water. The purpose of this study was to theoretically investigate the profitability of installing heat exchangers for wastewater on vertical sewer pipes in Glesvingen as well as determine which factors that affect the profitability the most. A calculation model based on existing data has been created in order to achieve this. This model then laid the foundation for specific theoretical energy calculations for Glesvingen. Data from Bostäder i Borås has also been3collected regarding temperatures as well as the amount of cold and hot water. In order to understand the profitability, various economical calculations have been made. In the result the amount of recovered energy and how it was affected by the number of wastewater sewer pipes in the building as well as the temperature of the wastewater flow was presented. The result also show the energy saving when the hot and cold wastewater flows are separated. Comparisons of the profitability calculations are presented as cost, savings and resulting savings over 50 and 25 years respectively. In conclusion, a compilation of different profitability calculations for Glesvingen has been made for different conditions. Regarding the installation of heat exchangers in Glesvingen, this investment is not considered profitable with the current building layout.
20

Utjämning av effekttoppar från avisning av tåg i Luleås fjärrvärmenät

Norell Helmsjö, David January 2021 (has links)
In the south-east part of the district heating network in Luleå, LKAB:S facility for de-icing their trains transporting iron ore is situated. The de-icing is done by sprayning the trains with hot water. The hot water is stored and heated in a basin, heated by district heating. When the de-icing starts the temperature in the basin drops and to restore it more heat is supplied from the district heating network. This results in peaks in the heat demand which causes high flows in the district heating system. The pipes in the district heating system are under-dimensioned and the high flows thereby causes high pressure gradients and a low pressure difference in the district heating grid. The objective of this project is to even out the peaks in the heat demand from the de-icing facility in order to minimize the maximal flows and improve the pressure difference in the grid. This was done by developing a heating strategy for the facility, using the basin to store energy as hot water. The strategy resulted in lower maximal peaks, where the highest peak during the studied period was reduced from 2430 kW to 1560 kW. In order to improve the return temperature in the gridfrom the facility a new heat-exchanger was dimensioned. The impact of these changes on thedistrict heating grid in Luleå was examined by simulations of the grid in the simulation software Netsim. These simulations showed that the pressure difference at the de-icing facility increased from 50 kPa with the current system to 200 kPa with the proposed changes. An investment assesment was conducted with respect to the heat exchanger for LKAB. It shows that the yearly flow costs are reduced and that the investment would be repayed within one to three years.

Page generated in 0.0527 seconds