umu.sePublikasjoner
Endre søk
Begrens søket
123 101 - 109 of 109
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 101.
    Vesterberg, Jimmy
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Evaluation of energy conservation measures in a multifamily building, using on site measurements2012Konferansepaper (Fagfellevurdert)
  • 102. Vicente, E.D.
    et al.
    Vicente, A.M.
    Evtyugina, M.
    Carvalho, Ricardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Centre for Environmental and Marine Studies, Department of Environment and Planning, University of Aveiro, Portugal.
    Tarelho, L.A.C.
    Paniagua, S.
    Nunes, T.
    Otero, M.
    Calvo, L.F.
    Alves, C.
    Emissions from residential pellet combustion of an invasive acacia species2019Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 140, s. 319-329Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, different types of raw materials are under investigation to fulfil the demand for pellet-based renewable energy. The aim of this study was to experimentally quantify and characterise the gaseous and particulate matter (PM10) emissions from the combustion of a pelletised invasive species growing in the Portuguese coastal areas. The combustion of acacia pellets in a stove used for domestic heating led to a noticeable production of environmentally relevant contaminants, such as carbon monoxide (CO, 2468 ± 485 mg MJ−1), sulphur dioxide (SO2, 222 ± 115 mg MJ−1) and nitrogen oxides (NOx, 478 ± 87 mg MJ−1). Besides gaseous pollutant emissions, substantial particle emissions (118 ± 14 mg MJ−1) were also generated. Particles consisted mostly of inorganic matter, mainly alkaline metals, sulphur and chlorine. About 25%wt. of the PM10 emitted had carbonaceous nature. The chromatographically resolved organic compounds were dominated by anhydrosugars, especially levoglucosan (284 μg g−1 PM10), and several types of phenolic compounds. Retene (8.77 μg g−1 PM10) was the chief compound among polyaromatic hydrocarbons.

  • 103.
    Vicente, Estela D.
    et al.
    Centre of Environmental and Marine Studies.
    Vicente, Ana
    Centre of Environmental and Marine Studies.
    Evtyugina, Margarita
    Centre of Environmental and Marine Studies.
    Carvalho, Ricardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Centre of Environmental and Marine Studies.
    Tarelho, Luís A. C.
    Centre of Environmental and Marine Studies.
    Oduber, Fernanda I.
    Department of Physics, Universidad de León.
    Alves, Célia
    Centre of Environmental and Marine Studies.
    Particulate and gaseous emissions from charcoal combustion in barbecue grills2018Inngår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 176, s. 296-306Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of charcoal for cooking and heating can be a major source of air pollution and lead to a wide range of health outcomes. The aim of this study was to experimentally quantify and characterise the gaseous and particulate matter (PM2.5) emissions from charcoal combustion in a typical brick barbecue grill. The gaseous emission factors were 219 ± 44.8 g kg−1 for carbon monoxide (CO), 3.01 ± 0.698 g kg−1 for nitrogen oxides (NOxexpressed as NO2), and 4.33 ± 1.53 gC kg−1 for total organic carbon (TOC). Particle emissions (7.38 ± 0.353 g kg−1 of dry charcoal burned) were of the same order of magnitude as those from traditional residential wood burning appliances. About 50% of the PM2.5 emitted had a carbonaceous nature while water soluble ions accounted, on average, for 17% of the particulate mass. Alkanes (C11–C16 and C23), hopanes, steranes and alkyl-PAHs accounted for small mass fractions of PM2.5. Phenolic compounds and saccharides represented the major particle-bond organic constituents. The high proportion of either resin acids or syringyl and vanillyl compounds is consistent with emissions from charred coniferous wood. The ratios between anhydrosugars for charcoal are much lower than the values reported for lignite combustion, but overlap those from other biomass burning sources.

  • 104.
    Weidemann, Eva
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Allegrini, E.
    Fruergaard Astrup, T.
    Hulgaard, T.
    Riber, C.
    Jansson, Stina
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Size fractionation of waste-to-energy boiler ash enables separation of a coarse fraction with low dioxin concentrations2016Inngår i: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 49, s. 110-113Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) formed in modern Waste-to-Energy plants are primarily found in the generated ashes and air pollution control residues, which are usually disposed of as hazardous waste. The objective of this study was to explore the occurrence of PCDD/F in different grain size fractions in the boiler ash, i.e. ash originating from the convection pass of the boiler. If a correlation between particle size and dioxin concentrations could be found, size fractionation of the ashes could reduce the total amount of hazardous waste. Boiler ash samples from ten sections of a boiler's convective part were collected over three sampling days, sieved into three different size fractions - <0.09 mm, 0.09-0.355 mm, and >0.355 mm - and analysed for PCDD/F. The coarse fraction (>0.355 mm) in the first sections of the horizontal convection pass appeared to be of low toxicity with respect to dioxin content. While the total mass of the coarse fraction in this boiler was relatively small, sieving could reduce the amount of ash containing toxic PCDD/F by around 0.5 kg per tonne input waste or around 15% of the collected boiler ash from the convection pass. The mid-size fraction in this study covered a wide size range (0.09-0.355 mm) and possibly a low toxicity fraction could be identified by splitting this fraction into more narrow size ranges. The ashes exhibited uniform PCDD/F homologue patterns which suggests a stable and continuous generation of PCDD/F.

  • 105.
    Widman, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Slamtorkning med lågvärdig värme på Dåva Kraftvärmeverk2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Förutsättningarna för att Umeå Energi ska kunna torka rötat avloppsslam från UMEVA med bland annat överskottsvärme från Dåva 1 har undersökts. Genom att beräkna hur mycket energi som finns tillgängligt och vilka slammängder som kan torkas har kostnaden för att installera och driva en slamtork uppskattats. Två modeller på slamtorkar (en bandtork från Hydropress Huber AB och en trumtork från AB Torkapparater) och fyra tänkbara driftscenarion, med avseende på torkperiod och slammängd, har undersökts.När slamtorkning sker under hela året och dagens produktion av slam (ca 7500 ton/år med 32 % TS) ska torkas till 90 % TS har ett intäktskrav på 215 kr/ton slam (våtvikt) beräknats för trumtorken och 255 kr/ton för bandtorken. Dessa värden representerar intäkten slammet måste ge för att torklösningen ska vara lönsam. Beräkningarna baseras på slammängder för de senaste fem åren och produktionsdata från Umeå Energis anläggningar för 2012-2013. Inget undersökt scenario kunde nyttja mer än 16 % av värmeöverskottet.Bandtorkens värden anses vara mest korrekta och användes för beräkna vilken intäkt som krävs för lönsamhet. Torkkostnaderna kan täckas om UMEVA betalar 100 kr/ton våtvikt och värmen från slamförbränning ger 180 kr/MWh. Om dubbla dagens slammängd ska torkas behöver värmen, med samma bidrag från UMEVA, bara ge 132 kr/MWh för att täcka torkkostnaderna. Utöver det kvarstår möjligheten till intäkt från fosforutvinning av aska att utredas.Torkning till 90 % TS kan vara onödigt högt och litteraturstudien visar att torkning till 70 % TS troligen skulle räcka för ändamålet. Detta skulle minska intäktskravet och bör därför utredas.

  • 106.
    Wiinikka, Henrik
    et al.
    Energy Technology Centre, Piteå, Sweden.
    Grönberg, Carola
    Energy Technology Centre, Piteå, Sweden.
    Öhrman, Olov
    Energy Technology Centre, Piteå, Sweden.
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Influence of TiO2 additive on vaporisation of potassium during straw combustion2009Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, nr 11, s. 5367-5374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, the influence of TiO2 on the vaporization of K during combustion of straw under fixed bed condition was investigated experimentally. Controlled combustion experiments with a varied amount of TiO2 in straw pellets were performed in an 8 kW pellet burner together with sampling of particles (impactor and absolute filter), analysis of the flue gas composition (Fourier transform infrared, FTIR), and chemical analyses of the collected particles and bottom ash (inductively coupled plasma-atomic emission spectroscopy (ICP-AES), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD)). The experimental results showed that the vaporization of K from the fuel bed was significantly reduced when TiO2 was used as an additive. The vaporization of K was reduced by ~40−50% for an optimal amount of TiO2 additive. The optimal added TiO2 for the straw used in this work corresponds to a Ti/K (wt) ratio between ~0.6−1.0. If more TiO2 was added to the fuel, the release of K to the gas phase was not further reduced and unreacted TiO2 was found in the bottom ash.

  • 107. Ögren, Yngve
    et al.
    Sepman, Alexey
    Qu, Zhechao
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Schmidt, Florian M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wiinikka, Henrik
    Comparison of measurement techniques for temperature and soot concentration in premixed, small-scale burner flames2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 10, s. 11328-11336Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optical and intrusive measurement techniques for temperature and soot concentration in hot reacting flows were tested on a small-scale burner in fuel-rich, oxygen-enriched atmospheric flat flames produced to simulate the environment inside an entrained flow reactor. The optical techniques comprised two-color pyrometry (2C-PYR), laser extinction (LE), and tunable diode laser absorption spectroscopy (TDLAS), and the intrusive methods included fine-wire thermocouple thermometry (TC) and electrical low pressure impactor (ELPI) particle analysis. Vertical profiles of temperature and soot concentration were recorded in flames with different equivalence and O2/N2 ratios. The 2C-PYR and LE data were derived assuming mature soot. Gas temperatures up to 2200 K and soot concentrations up to 3 ppmv were measured. Close to the burner surface, the temperatures obtained with the pyrometer were up to 300 K higher than those measured by TDLAS. Further away from the burner, the difference was within 100 K. The TC-derived temperatures were within 100 K from the TDLAS results for most of the flames. At high signal-to-noise ratio and in flame regions with mature soot, the temperatures measured by 2C-PYR and TDLAS were similar. The soot concentrations determined with 2C-PYR were close to those obtained with LE but lower than the ELPI results. It is concluded that the three optical techniques have good potential for process control applications in combustion and gasification processes. 2C-PYR offers simpler installation and 2D imaging, whereas TDLAS and LE provide better accuracy and dynamic range without calibration procedures.

  • 108.
    Östin, Ronny
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energy performance and lessons learned from detailed measurement of a passive house preschool in cold climate2019Inngår i: Is efficient sufficient?: eceee 2019 Summer Study on energy efficiency: Abstracts, European Council for an Energy Efficient Economy (ECEEE), 2019, s. 1433-1442Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Public passive house buildings are rare in high northern latitudes. This study reports on extensive measurements and evaluations of the most northerly (640 N) built passive house preschool in Sweden. The two storied preschool, built in 2014, has a total heated floor area of 1407 m2. The building was certified according to the international passive house standard. The building has several smart solutions such as demand controlled ventilation of individual rooms and automatic solar shading system.

    Energy measurements conducted during 2017-2018 showed that the preschool annually uses 44.4 kWhm-2, which is approximately 25 % lower than the passive house requirement for energy demand. However, the annual specific space heating requirement of 15 kWhm-2 and the peak heat power demand of 10 Wm-2 were not fulfilled. This non-compliance was mainly due to excessive ventilation during the heating season which was found to have 2.7 times higher air changes than the requirement in the Swedish building code. Furthermore, the building was found to be over heated from the sun during several occasions in a year. For example, excessive indoor air temperatures in the range 28 – 31°C were found during summer.

    The study revealed that the default winter operation by turning off the ventilation system during nights and weekends is continued in other seasons as well. This practice was not a “smart” approach for the air handling units as it was found to be one of the reasons for high indoor temperatures during non-winter months. Also, a mismatch between the operation of the automatic shading device and the ventilation control units was noted.

    The investigation shows that smart technical solutions in buildings may not be able to deliver its’ promised results if such systems are not monitored, adjusted and carefully evaluated. The paper identifies areas that need attention to ensure that a public building built to passive house standard actually deliver the energy efficiency it promises.

  • 109. Ürge-Vorsatz, Diana
    et al.
    Köppel, Sonja
    Liang, Chunyu
    Benigna, Kiss
    Nair, Gireesh
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling, Östersund.
    Celikyilmaz, Gamze
    An assessment of energy service companies (ESCOs) worldwide2007Rapport (Annet (populærvitenskap, debatt, mm))
123 101 - 109 of 109
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf