https://www.mdu.se/

mdh.sePublikasjoner
Endre søk
Begrens søket
1234567 1 - 50 of 1091
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.
  • 1.
    Abadi, Imam
    et al.
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Hardiana, Tiara Oktavia
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Imron, Chairul
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Fitriyanah, Dwi Nur
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Jani, Yahya
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM), Sweden.
    Abdullah, Kamaruddin
    Darma Persada University, Indonesia.
    Design of Adaptive Neuro-Fuzzy Inference Control Based One-Axis Solar Tracker on Battery Charging System2020Inngår i: E3S Web of Conferences, EDP Sciences , 2020, s. 1-15, artikkel-id 00015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The photovoltaic (PV) panel can produce electrical energy that is very environmentally friendly and easy to use. The use of PV panels is suitable for supplying peak loads or at night using batteries as energy storage. However, the battery needs to manage for control, and the battery can last long. The solution to battery management problems is through research about the battery charging system. The DC-DC converter used is the Single Ended Primary Inductance Converter (SEPIC) type. Voltage Control of the battery charging using Adaptive Neuro-Fuzzy Inference System (ANFIS). In the simulation of bright conditions, ANFIS controls can track the charging point set point and obtain a voltage response with a rise time of 0.0028 s, a maximum overshoot of 0.027 %, a peak time of 0.008 s, and a settling time of 0.0193 s. When charging a solar tracker, PV battery gets a 0.25 % increase compared to a fixed PV panel. PV solar tracker can follow the direction of the sun's position. The irradiation value and maximum temperature affect the input voltage and input current that enters the converter. 

  • 2.
    Abadi, Imam
    et al.
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Uyuniyah, Qurrotul
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Fitriyanah, Dwi Nur
    Institut Teknologi Sepuluh Nopember, Indonesia.
    Jani, Yahya
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM), Sweden.
    Abdullah, Kamaruddin
    Darma Persada University, Indonesia.
    Performance Study of Maximum Power Point Tracking (MPPT) Based on Type-2 Fuzzy Logic Controller on Active Dual Axis Solar Tracker2020Inngår i: E3S Web of Conferences, EDP Sciences , 2020, s. 1-16, artikkel-id 00016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    World energy consumption increases with time, so that occur an energy imbalance. Many breakthroughs have developed to utilize renewable energy. The photovoltaic system is one of the easy-to-use renewable energies. The power conversion from PV fixed is still low, so the PV system is designed using the active dual-axis solar tracker. The PV tracker position can be adjusted to change the sun position to get maximum efficiency. The active dual-axis solar tracker system is integrated with the maximum power point tracking (MPPT) algorithm to keep PV operating at a maximum power point even though input variations change. The active dual-axis solar tracker system integrated with the maximum power point tracking (MPPT) algorithm to keep PV operating at a maximum power point even though input variations change. Tracking test simulation had done by comparing the output power of a fixed PV system with the active dual-axis solar tracker. Type-2 fuzzy logic based MPPT successfully increased the average output power by 10.48 % with the highest increase of 17.48 % obtained at 15:00 West Indonesia Time (GMT+7). The difference in power from a fixed PV system with the active dual-axis solar tracker of 36.08 W is from the output power worth 206.3 to 242.4 W. 

  • 3.
    Abas, N.
    et al.
    University of Gujrat, Hafiz Hayat Campus, Gujrat, Pakistan.
    Kalair, A. R.
    COMSATS University Islamabad, Islamabad, Pakistan.
    Seyedmahmoudian, M.
    Swinburne University, Australia.
    Naqvi, M.
    Karlstad University.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Khan, N.
    COMSATS University Islamabad, Islamabad, Pakistan.
    Dynamic simulation of solar water heating system using supercritical CO2 as mediating fluid under sub-zero temperature conditions2019Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 161, artikkel-id 114152Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CO2 is becoming increasingly important as a mediating fluid, and simulation studies are indispensable for corresponding developments. In this study, a simulation-based performance investigation of a solar water heating system using CO2 as a mediating fluid under sub-zero temperature condition is performed using the TRNSYS® software. The maximum performance is achieved at a solar savings fraction of 0.83 during July. The as lowest solar savingss fraction of 0.41 is obtained during December. The annual heat production of the proposed system under Fargo climate is estimated to be about 2545 kWh. An evacuated glass tube solar collector is designed, fabricated and tested for various climate conditions. Moreover, a detailed comparison of the system's performance at sub/supercritical and supercritical pressures shows that the annual heat transfer efficiency of the modeled system is 10% higher at supercritical pressure than at sub/supercritical pressures. This result can be attributd to the strong convection flow of CO2 caused by density inhomogeneities, especially in the near critical region. This condition resuls in high heat transfer rates.

  • 4.
    Abdelshafy, Alaaeldin M.
    et al.
    Egypt Japan Univ Sci & Technol, Energy Resources Eng Dept, Alexandria, Egypt.;Assiut Univ, Fac Engn, Elect Engn Dept, Assiut, Egypt..
    Jurasz, Jakob
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi. AGH Univ Sci & Technol, Fac Management, Dept Eng Management, Krakow, Poland..
    Hassan, Hamdy
    Egypt Japan Univ Sci & Technol, Energy Resources Eng Dept, Alexandria, Egypt.;Assiut Univ, Fac Engn, Mech Engn Dept, Assiut, Egypt..
    Mohamed, Abdelfatah M.
    Assiut Univ, Fac Engn, Elect Engn Dept, Assiut, Egypt.;Egypt Japan Univ Sci & Technol, Dept Mechatron & Robot Engn, Alexandria, Egypt..
    Optimized energy management strategy for grid connected double storage (pumped storage-battery) system powered by renewable energy resources2020Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 192, artikkel-id 116615Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a grid-connected double storage system (DSS) consisting of pumped-storage hydropower (PSH) and battery. The system is supplied by photovoltaics and wind turbines. In the proposed hybrid system, batteries absorb excess renewable energy that cannot be stored in PSH and they cover loads that cannot be supplied from the water turbine. To improve the system performance, a novel energy management strategy for the DSS is proposed. The strategy is based on an optimized factor that governs the charging process of the DSS. The problem of the optimal system design is solved by a non-dominated sorting genetic algorithm (NSGA-II). The multi-objective function considers simultaneously the minimal investment cost and minimal CO2 emissions. A comparative study of photovoltaic/wind/pumped-storage hydropower and photovoltaic/wind/double storage system is performed to show the effectiveness of the proposed strategy in terms of system economic and environmental performance. The considered location of the PSH station is on Attaqa Mountain at Suez (Egypt). The results indicate the effectiveness of the proposed energy management strategy for the storage system from economic and environmental perspectives. Coupling the battery with the PSH reduces the electricity cost by 22.2% and results in minimal energy exchange with the national grid (5% of the annual demand). A sensitivity analysis shows the largest variation of the electricity cost with changing the capital cost of the solar and wind generators. Also, it is observed that when the load increases, the optimal size of the system components increases, but it isn't proportional with the demand increase as could be expected. (C) 2019 Elsevier Ltd. All rights reserved.

  • 5.
    Afrim, Amanda
    et al.
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik.
    Kling, Jennifer
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik.
    UTVECKLING AV DEBITERINGSSYSTEM FÖR REDUCERING AV ENERGIANVÄNDNING: Uppdrag av Saab AB, Linköping2022Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this master thesis is to develop a billing system for Saab's energy use and to study the possibilities for improving energy efficiencies. The billing system is based on collected measurement data and is divided into different categories. Obtained measurement data refer to one year in a pandemic between the years 2020 and 2021, which affects the results due to employees working from home as offices are closed. Furthermore, energy use must be normalized to be able to compare the energy use despite the temperature difference each month. Thereafter, normalized energy use is divided with the area for each house. The average value calculated for offices is 133 kWh/m2 compared to the general average value at 110 kWh/m2 and entails a high cost. The swingtherm plant consumes the most energy per square meter, over 2000 kWh/m2. The billing system is developed in Excel and implemented in Space. The billing model affects all internal tenants within Saab's operations. The possibilities for improving energy efficiencies have been studied and analyzed. Effective measures that are highlighted is an increased awareness, a change in the individual's behavior, integration of drill hole system, FTX system and installation of heat recovery and LED lights.

  • 6.
    Agrell, Filip
    et al.
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik.
    Ablay, Agit
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik.
    Developing an innovative unit of power supply to improve the sustainability of data centers: A techno economic analysis of replacing diesel generators with fuel cells as backup power generation for data centers2022Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    As the amount of data centers continues to increase, their electricity consumption and emissions are being reviewed. The current backup solution is a conventional diesel generator running on fossil fuels. As part of climate goals to reduce carbon emissions, renewable energy sources like fuel cells running on hydrogen are being considered. The following degree project aims to analyse the impact of replacing a fossil-powered backup power system with fuel cells as well as providing insights into which parameters affect the economic analysis the most. Current studies, reports and websites were used to gather a better understanding of fuel cell systems and their key components. The calculations were carried out using values obtained from literature which then were used for simulations in Excel. The results indicated a net profit for the proposed fuel cell system during the expected lifetime. A proton exchange membrane fuel cell (PEMFC) functions very similarly to a diesel generator while reducing emissions. While the operating costs for the conceptual FC system are lower, the initial investment is much more expensive compared to the diesel system. Even though the economic investment yields a negative profit, large carbon dioxide savings are made. To give a better understanding of how different aspects impact the economics a sensitivity analysis was also carried out. While the current results show that the investment is not feasible, many of the parameters analysed in the sensitivity analysis indicate a more hopeful future forecast.  

    Fulltekst (pdf)
    Thesis_Ablay_Agrell
  • 7.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens universitet, Akademin för innovation, design och teknik, Inbyggda system.
    Andersson, Peter
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Andersson, Tim
    Mälardalens universitet, Akademin för innovation, design och teknik, Inbyggda system.
    Tomas Aparicio, Elena
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Mälarenergi AB, Sweden.
    Baaz, Hampus
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Barua, Shaibal
    Mälardalens universitet, Akademin för innovation, design och teknik, Inbyggda system. RISE SICS Västerås, Sweden.
    Bergström, Albert
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bengtsson, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Orisio, Daniele
    State Inst Higher Educ Guglielmo Marconi, Dalmine, Italy..
    Skvaril, Jan
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zambrano, Jesus
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A Machine Learning Approach for Biomass Characterization2019Inngår i: Energy Procedia, ISSN 1876-6102, s. 1279-1287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this work is to apply and evaluate different chemometric approaches employing several machine learning techniques in order to characterize the moisture content in biomass from data obtained by Near Infrared (NIR) spectroscopy. The approaches include three main parts: a) data pre-processing, b) wavelength selection and c) development of a regression model enabling moisture content measurement. Standard Normal Variate (SNV), Multiplicative Scatter Correction and Savitzky-Golay first (SGi) and second (SG2) derivatives and its combinations were applied for data pre-processing. Genetic algorithm (GA) and iterative PLS (iPLS) were used for wavelength selection. Artificial Neural Network (ANN), Gaussian Process Regression (GPR), Support Vector Regression (SVR) and traditional Partial Least Squares (PLS) regression, were employed as machine learning regression methods. Results shows that SNV combined with SG1 first derivative performs the best in data pre-processing. The GA is the most effective methods for variable selection and GPR achieved a high accuracy in regression modeling while having low demands on computation time. Overall, the machine learning techniques demonstrate a great potential to be used in future NIR spectroscopy applications.

    Fulltekst (pdf)
    fulltext
  • 8.
    Akbari, Keramatollah
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Impact of Radon Ventilation on Indoor Air Quality and Building Energy saving2009Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Industrial living is caused much people do live and work in closed and confined places; offices and residential buildings. This is why in this new world more fresh air which is generally provided by forced ventilation plays a vital role in living of human being. Furthermore because of many different indoor pollutants, like radon and artificial pollutants, the amount of fresh air and in turn the energy consumption has increased. This energy consumption related to ventilation has reached up to about 30 percent of energy used of building section. So making interaction between indoor air quality (IAQ) and optimization of energy saving is a necessary work.  Radon as a natural pollutant is occurred in environment and in many countries threatens people health whereas is called the second causes of cancer. For reducing radon concentration in residential building at the acceptable level forced ventilation is used usually. Ventilation can improve IAQ but in the other side would increase the energy consumption in building sector and just now the contribution of ventilation exceeds up 50 percent of building sector's share. The aim of this thesis is to study the impact of ventilation on indoor radon by using Computational Fluid Dynamics (CFD) to achieve indoor air quality and energy efficiency. Application of CFD as a new technology, because of its cost and time savings, and on the other side, of its flexibility and precision is  increasingly grown and can be used as a very important and valuable tool for the prediction and measurement of radon distribution in a ventilated building . Currently, measurement techniques and proposed standards and regulations of indoor pollutants and ventilation, particularly related to indoor radon cannot be able to provide a secure, safe and energy efficient indoor climate. This is why the indoor airflow distribution is very complex and with changing building geometry and operation condition, the treatment of air flow pattern, substantially would be changed, whereas the rules are usually independent of the buildings features. Furthermore, the indoor standards and regulations are based on average amount of pollutants in a room, whereas the pollutant distributions aren't identical and are varied throughout the room. Then the current techniques aren't so exactly valuable and acceptable.

    From different methods which is privilege to control pollutants, ventilation method is applicable in existing buildings. Designing effective ventilation can reduce radon concentration to very level low with regarding energy conservation remarks.

     

    This thesis presents results from simulation studies on ventilation and radon mitigation in residential buildings, in view points of indoor air quality and energy savings. The CFD technique is applied to predict, visualize and calculate of mixture radon-air flow. The distribution of indoor radon concentration, air velocity and room temperature also have considered together for achieving indoor air quality and energy saving. The results are also compared with the experimental data and related previous works.

     

    It was found that with increasing ventilation rate, the radon concentration is decreased, but the location of ventilation system is also important. From the simulation results, it is observed that within the ventilated room, there are some zones, which are good for living and somewhere is more polluted. The traditional radon detectors basically show the average value of radon content in 1m­3 of air. That is why detector measuring is not exact and safe.

     

    Simulation results proved that floor heat can be supported ventilation effect and speed up the mixture movement. Floor heating reinforces the buoyancy effect, which is useful to reduce radon content in the floor (seating area) and then lower ventilation rate can be applied.

    Fulltekst (pdf)
    FULLTEXT01
  • 9.
    Akbari, Keramatollah
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Simulation of Indoor Radon and Energy Recovery Ventilation Systems in Residential Buildings2015Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This study aims to investigate the effects of ventilation rate, indoor air temperature, humidity and using a heat recovery ventilation system on indoor radon concentration and distribution.

    Methods employed include energy dynamic and computational fluid dynamics simulation, experimental measurement and analytical investigations. Experimental investigations primarily utilize a continuous radon meter and a detached house equipped with a recovery heat exchanger unit.

    The results of the dynamic simulation show that the heat recovery unit is cost-effective for the cold Swedish climate and an energy saving of about 30 kWh per  floor area per year is possible, while it can be also used to lower radon level.

    The numerical results showed that ventilation rate and ventilation location have significant impacts on both radon content and distribution, whereas indoor air temperature only has a small effect on radon level and distribution and humidity has no impact on radon level but has a small impact on its distribution.

    Fulltekst (pdf)
    fulltext
  • 10.
    Akel Hasan, A.
    et al.
    Mechanical & Mechatronics Engineering Department, Birzeit University, Palestine.
    Juaidi, A.
    Mechanical & Mechatronics Engineering Department, Faculty of Engineering & Information Technology, An-Najah National University, Nablus, Palestine.
    Abdallah, R.
    Mechanical & Mechatronics Engineering Department, Faculty of Engineering & Information Technology, An-Najah National University, Nablus, Palestine.
    Salameh, T.
    Department of Sustainable and Renewable Energy Engineering, University of Sharjah, Sharjah, United Arab Emirates.
    Ayadi, O.
    Mechanical Engineering Department, The University of Jordan, Amman, Jordan.
    Jaradat, M.
    Energy Engineering Department, German Jordanian University, Amman, Jordan.
    Emad Hammad, R.
    Environmental and Renewable Energy Engineering, German Jordanian University, Jordan.
    Campana, Pietro Elia
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Afif Aqel, O.
    Department of Mechanical Engineering and Aeronautics, City, University of London, Northampton Square, London, United Kingdom.
    A review of solar thermal cooling technologies in selected Middle East and North African countries2022Inngår i: Sustainable Energy Technologies and Assessments, ISSN 2213-1388, E-ISSN 2213-1396, Vol. 54, artikkel-id 102871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cooling loads are a substantial part of the total electricity demands of countries in the Middle East and North Africa (MENA). Fortunately, because of its warm and sunny climate, the MENA region is naturally suited to solar cooling technologies. This article summarizes the most recent research and developments in solar thermal cooling technologies. The working principles and a general literature survey of solar thermal cooling technologies including absorption, adsorption, and desiccant is presented. This is followed by a summary of the literature specific to the MENA region, along with a survey of the prototypes and commercial installation of solar cooling across the MENA region. Based on this review, pilot solar cooling projects in the region are around 1180 kWc, which are split between space conditioning and industrial refrigeration applications. Most of the pilot projects are of absorption cooling type using an ammonia–water binary cycle and parabolic trough solar collectors. However, a few adsorption cooling systems are employed with a water–silica working pair and flat plate collectors. Finally, desiccant cooling systems are still in their infancy, as research and experimental systems in educational institutes.

  • 11.
    Akter, Salina
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Islam, M. Sirajul
    Örebro Univ, Sch Business, Örebro.
    Factors influencing the attitude of women towards purchasing green products: An explorative case study of organic cosmetics in sweden2020Inngår i: JOURNAL OF CONSUMER SCIENCES, ISSN 0378-5254, Vol. 48, s. 38-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates green consumer behavior by analyzing women's attitudes towards purchasing organic cosmetics in Sweden in order to determine the factors that influence their purchasing behavior. The study is based on the modified Theory of Planned Behavior (TPB) explained with primary data collected through an online survey of 220 women who live in Sweden. The findings are in line with the previous studies, which confirm that consumers' attitudes towards green products have a positive influence on purchase intention. Moreover, this study has found that the individual's education and income level have a positive relationship with attitude and future purchase intention.

  • 12.
    Al Hamrani, Emad
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Gibrael, Nemir
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Fast determination of fuel/feedstock material properties and composition: By Near infrared (NIR) spectroscopy2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    Fast determination of fuel/feedstock material properties and composition
  • 13.
    Alinejad, T.
    et al.
    School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
    Yaghoubi, M.
    School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
    Vadiee, Amir
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thermo-environomic assessment of an integrated greenhouse with an adjustable solar photovoltaic blind system2020Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 156, s. 1-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimum energy consumption and renewable energy utilization reduce environmental impacts and are cost-effective. They are the key aspects of achieving sustainable energy management, such as in the agricultural industry. The contribution of the horticultural section in the global energy demand is approximately 2%, and among its various sections, greenhouses are one of the main systems in modern agriculture that have a great share on energy consumption. In this study, a rose greenhouse is examined and modeled in EnergyPlus as a greenhouse reference (GR). Validation of the developed greenhouse model is carried out with a site experimental measurement. Using the GR as the basic model, 14 various configurations of greenhouses have been assessed by considering a solar photovoltaic blind system (SPBS) in checkerboard arrays 1 m above the greenhouse roof. These modified greenhouses called solar-blind greenhouses (SBGs) have different shading rates and SPBS sizes. To perform a Thermo-environomic assessment, the effects of various parameters, including temperature, relative humidity, natural gas consumption, electricity consumption, and carbon dioxide (CO2) emission reduction, are studied. Results indicate that covering 19.2% of the roof, with no significant change in the illumination level on the plant canopy, will annually reduce natural gas consumption, electricity demand, and CO2 emission by 3.57%, 45.5%, and 30.56 kg/m2, respectively. Moreover, with the SPBS, the annual electricity production is approximated at 42.7 kWh/m2. © 2020 Elsevier Ltd

  • 14.
    Alirahmi, S. M.
    et al.
    Department of Chemistry and Bioscience, Aalborg University, Niels Bohrs Vej, Esbjerg, Denmark.
    Behzadi, A.
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Ahmadi, P.
    School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Sadrizadeh, Sasan
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An innovative four-objective dragonfly-inspired optimization algorithm for an efficient, green, and cost-effective waste heat recovery from SOFC2023Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 263, artikkel-id 125607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work proposes a novel yet practical dragonfly optimization algorithm that addresses four competing objectives simultaneously. The proposed algorithm is applied to a hybrid system driven by the solid oxide fuel cell (SOFC) integrated with waste heat recovery units. A function-fitting neural network is developed to combine the thermodynamic model of the system with the dragonfly algorithm to mitigate the calculation time. According to the optimization outcomes, the optimum parameters create significantly more power and have a greater exergy efficiency and reduced product costs and CO2 emissions compared to the design condition. The sensitivity analysis reveals that while the turbine inlet temperatures of power cycles are ineffective, the fuel utilization factor and the current density significantly impact performance indicators. The scatter distribution indicates that the fuel cell temperature and steam-to-carbon ratio should be kept at their lowest bound. The Sankey graph shows that the fuel cell and afterburner are the main sources of irreversibility. According to the chord diagram, the SOFC unit with a cost rate of 13.2 $/h accounts for more than 29% of the overall cost. Finally, under ideal conditions, the flue gas condensation process produces an additional 94.22 kW of power and 760,056 L/day of drinkable water. 

  • 15.
    Alothman alsaghir, Karima
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik.
    ENVIRONMENTAL AND ECONOMIC IMPACT OF USING RECYCLED MATERIALS IN WALL INSULATION: Energy management for sustainable cities, ETC building project.2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Recycled material has attracted extensive interest due to its positive impact on decarbonization in the building sector. At the same time, utilizing these materials is limited. The main objective of this degree project is to provide a better understanding of recycled materials and their role in environmental and economic aspects. This work investigates three cases regarding the use of recycled materials as external wall insulation in ETC buildings: Case 1 (biochar), Case 2 (plastic waste materials), and Case 3 (straw bales), and the cases will be compared with Case 0 (wood) materials that are used in the building. Thermal insulation properties such as thermal conductivity and density are the most important factors influencing this material's ability to insulate. These properties are used as variables in simulation; each variable is linked to the type of material used. Models were created for each material in the building performance simulation tool IDA ICE. In each model, the insulation of the external walls will be changed, but the rest of the construction specifications will stay unchanged. The results showed that all the materials selected in the evaluation have a low environmental impact (thermo-environmental assessment), low energy demand, and low carbon emissions. In the case of comparing the three cases 1, 2, and 3 of recycled materials, the results indicated that Case 1 (biochar) has the same environmental impact as Case 0 (wood), but the energy used was more than Case 0 by 6%, and the economic impact (thermoeconomic assessment)regarding energy costs has the same value. There is no information regarding the material’s price. The results showed that Case 3 (straw bales) has a lower environmental and economic impact than wood. The results illustrated that adding Case2 (EPS) with a thickness of 200 to the wooden building reduced demand by 3% for heating and cooling, and the energy used was less than 2%. Therefore, Case0 (wood) support with this layer is considered an appropriate solution to reduce energy demand. On the other hand, recycled materials have challenges in terms of insufficient research on the extent of their use, as in the case of biochar in Sweden. As well as challenges related to the development of strawbales, which have many problems related to rotting and moisture absorption

    Fulltekst (pdf)
    fulltext
  • 16.
    Amanatidou, Rebeka
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    CFD Measurements of the Cooling Air in a DC-Motor2008Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

     

    The cooling system of a DC-motor is examined in this thesis. A change of direction of the cooling air is desired to prevent the generated coal dust from entering into the windings of the machine. Ultimately this will have a negative effect on the cooling in the machine and the loss of cooling needs to be compensated through other ways. The purpose of this thesis is to work for an improved operational safety and performance of the DC-motor and to make it more competitive in the market. By modelling the interior geometry of the machine and defining the boundaries in the software programs Gambit and FLUENT respectively, the motion and the heat transfer of the airflow could be simulated. The simulation results would give us an understanding of the flow pattern which later could be used to develop design modifications on the cooling system of a DC-motor. In this thesis the main focus lies on creating a simulation model with a sufficiently fine mesh size.

    Fulltekst (pdf)
    FULLTEXT01
  • 17.
    Amini, E.
    et al.
    Department of Civil, Environmental, Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, United States.
    Nasiri, M.
    Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.
    Pargoo, N. S.
    Department of Civil, Environmental, Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, United States.
    Mozhgani, Z.
    Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.
    Golbaz, D.
    Center for Applied Coastal Research, Civil and Environmental Engineering, University of Delaware, Newark, DE, United States.
    Baniesmaeil, M.
    Department of Marine Industries, Islamic Azad University, Science and Research Branch, Tehran, Iran.
    Majidi Nezhad, Meysam
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Neshat, M.
    Faculty of Engineering and Information Technology, University of Technology Sydney, Ultimo, NSW, Australia.
    Astiaso Garcia, D.
    Department of Planning, Design, Technology of Architecture, Sapienza University of Rome, Rome, Italy.
    Sylaios, G.
    Laboratory of Ecological Engineering and Technology, Department of Environmental Engineering, Democritus University of Thrace, Xanthi, Greece.
    Design optimization of ocean renewable energy converter using a combined Bi-level metaheuristic approach2023Inngår i: Energy Conversion and Management: X, ISSN 2590-1745, Vol. 19, artikkel-id 100371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years, there has been an increasing interest in renewable energies in view of the fact that fossil fuels are the leading cause of catastrophic environmental consequences. Ocean wave energy is a renewable energy source that is particularly prevalent in coastal areas. Since many countries have tremendous potential to extract this type of energy, a number of researchers have sought to determine certain effective factors on wave converters’ performance, with a primary emphasis on ambient factors. In this study, we used metaheuristic optimization methods to investigate the effects of geometric factors on the performance of an Oscillating Surge Wave Energy Converter (OSWEC), in addition to the effects of hydrodynamic parameters. To do so, we used CATIA software to model different geometries which were then inserted into a numerical model developed in Flow3D software. A Ribed-surface design of the converter's flap is also introduced in this study to maximize wave-converter interaction. Besides, a Bi-level Hill Climbing Multi-Verse Optimization (HCMVO) method was also developed for this application. The results showed that the converter performs better with greater wave heights, flap freeboard heights, and shorter wave periods. Additionally, the added ribs led to more wave-converter interaction and better performance, while the distance between the flap and flume bed negatively impacted the performance. Finally, tracking the changes in the five-dimensional objective function revealed the optimum value for each parameter in all scenarios. This is achieved by the newly developed optimization algorithm, which is much faster than other existing cutting-edge metaheuristic approaches. 

  • 18.
    Andersson, Alexander
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Lindström, FAHRIYE Cennet
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    ENERGIANALYS AV FASTIGHETEN ANDERSLUND 12: Energieffektiviseringsmöjlighet med solceller2021Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today's society is dependent on energy and the increasing use of energy affects the environment in a negative way. In Sweden, homes and premises account for 39% of total energy use. Achieving national environmental quality goals requires a reduction in energy use and the energy saving potential in the real estate sector is large. Energy use in buildings can be reduced by carrying out certain energy efficiency measures.

    Kårhuset by Mälardalen University was built in 1997 and it is a gathering place for students. The building is located on the campus area in Västerås and includes an office, restaurant kitchen, dining room, pub and meeting rooms for line associations.

    In this work, an energy survey has been carried out by the property Anderslund 12 (Kårhuset) to find out the current energy use and investigate the energy saving potential in the building. 

    The work's literature study analyzes previous research and similar case studies. Thereafter, the building's energy use has been simulated by IDA ICE by creating a basic model in the software using data from various authorities and site visits. The results of the basic model were then compared with simulations of various energy efficiency measures to evaluate the energy saving potential. The measures examined are window replacement, additional insulation of exterior walls and replacement of heat exchangers in the air handling units. As a complementary alternative, energy efficiency with solar cells on the roof was investigated.

    The conclusion is that the property's energy use exceeds the average of Swedish premises' energy use. In connection with a possible renovation, the building has good opportunities for more efficient energy use. By carrying out all the measures that have been proposed, the heating demand can be reduced by 39% and the energy supplied can be reduced from 156.9 kWh / m2, Atemp, year to 103 kWh / m2, Atemp, year. Complementary installation of solar cells is a profitable alternative for reducing the building's extremely high electricity consumption.

    Fulltekst (pdf)
    fulltext
  • 19.
    Andersson, Anna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Carlsson, Eva-Sara
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Structures in Underground Facilities: Analysis of a Concrete Column’s Capacity toWithstand Extraordinary Fire Loads2012Rapport (Annet vitenskapelig)
    Abstract [en]

    This report presents a Master of Science in Engineering work, carried out at Mälardalen’sUniversity within the research project METRO. The aim for this work was to determineif a concrete column placed close to the tracks at a subway station can withstand theeffect and temperature of a fire in a burning train comparable to the effects and temperaturesthat showed at the full scale test carried out within the METRO project. A literature review was made before a following case study. The results from thiswork show that the column is negligible affected by the fire.

    Fulltekst (pdf)
    fulltext
  • 20.
    Andersson, Daniel
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Energiuppföljning av verkligt energibehov kontra beräknat för Hälleborgsäldreboende: Sveriges modernaste äldreboende2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Examensarbetet utförs under sista årets energiingenjörsstudier vid Mälardalens högskola. Med hjälp av Ramböll Västerås utfördes en energiuppföljning av energiförbrukningen vid Hälleborgs äldreboende beläget på Bäckby i Västerås åt Västerås stad.

    Hälleborgs äldreboende stod klart och var fullt inflyttat våren 2015. Boendet byggdes för att möta det ökade behovet av vårdplatser i Västerås kommun. Vid byggnationen ställde kommunen ett byggkrav på 60 kWh/(m2,år) köpt energi vilket var hårdare än de gällande byggkraven som gällde i Sverige vid dåvarande tidpunkt.

    Under projekteringen av byggnaden ändrades kravet till 70 kWh/(m2,år) viktad energi där fjärrvärmen viktas med 1 och elen med 2.  Ändringen uppkom efter att behovet av kyla kunde lösas med ett borrhålslager vilket ger möjlighet att ta tillvara på värmen som kyls bort via värmepumpar. Byggnadens värmebehov tillgodoses av både värmepumpar och fjärrvärme vilket innebär olika energikrav enligt BBR, viktningen görs för att få ett mellanting mellan kraven för byggnad med el uppvärmning och byggnad utan eluppvärmning.

    Examensarbetet går ut på att utreda om byggnadens energianvändning går att följa upp efter ett år i drift. Genom att försöka beräkna förbrukningen och på den vägen upptäcka problem som behöver åtgärdas till 2 årsuppföljning 2017.

    Det har under arbetets gång visat sig att anläggningens mätsystem inte fungerar som tänkt vad det gäller överföring mellan fastighetens mätssystem och Västerås stads mätdata hanteringssystem Momentum. Men även när mätdatainformationen skulle hämtas manuellt visades sig att det endast fanns för ett fåtal datum vilket gjorde det omöjligt att ställa upp en årsenergi. För att kontrollera att mätningen fungerade som det skulle ställdes en sammanställning upp för perioden 2015-02-22 och 2016-03-24 vilket visade att all elproduktion inte registreras i de interna mätarna.

    Fjärrvärmen var enda energienhet som kunde verifieras då den förbrukningen hämtades från fjärrvärmeleverantören Mälarenergi AB. Fjärrvärmeförbrukningen uppgick till 29 kWh/ kWh/(m2,år) mot projekterade 11.7 kWh/ kWh/(m2,år). För att kunna utföra en korrekt energiuppföljning och visa tappvarmvatten förbrukningen behöver fastigheten uppdateras med fler mätare. Dels behövs en mätare som mäter levererad fjärrvärmeenergi till tappvarmvattnet och det rekommenderas även att registrera en flödesmätare på tappvarmvattnet till verksamheten.

    Det bör även undersökas vilka elförbrukningar som inte omfattas av internmätning för att kunna skilja verksamhets- och fastighetsenergi åt. Elenergin för undermätarna var 555 406 kWh för perioden 2015-02-22 och 2016-03-24 och motsvarnade 924 025 kWh för nätägaren Mälarenergi i perioden 2015-05-01 till 2016-04-30. För att kunna utföra en balans ska undermätarna uppgå till samma förbrukning som huvudmätaren för samma mät period.

    Byggnaden uppfyller idag inte förutsättningar för att kunna göra en korrekt energiuppföljning. 

    Fulltekst (pdf)
    fulltext
  • 21. Andersson, Henny
    et al.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jansson, Joakim
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Suhonen, Anssi
    Savonia University of Applied Sciences, University of Eastern Finland, Finland.
    Jääskeläinen, Ari
    Savonia University of Applied Sciences, University of Eastern Finland, Finland.
    Reijonen, Tero
    Laatikainen, Reino
    Heitto, Anneli
    Hakalehto, Elias
    TECHNICAL REPORT ON PILOT A TESTS IN SWEDEN2015Rapport (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 22.
    Andersson, Oskar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Avskiljning av inert material från avfallsbränsle: En fältstudie av förbättrad RDF-produktion på bränsleberedningen i Västerås2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Samtidigt som världens energiproduktion till stor del baseras på förbränning av fossila bränslen behandlas enorma mängder avfall genom deponering. Ökad energiåtervinning av avfall kan bidra till att minska världens utsläpp av växthusgaser. Då avfall bör ses som en resurs är det dock viktigt med en effektiv energiåtervinning. Förbränning i fluidbäddspanna möjliggör god förbränning och hög verkningsgrad men kräver ett finfördelat avfall med lågt innehåll av inert (icke brännbart) material, så kallat RDF. Därför behöver avfallet beredas innan förbränning. En effektiv och välfungerande beredning av avfallsbränsle möjliggör resurseffektiv avfallshantering av utsorterade fraktioner samt effektiv förbränning genom hög bränslekvalitet.

    Mälarenergis panna 6 på kraftvärmeverket i Västerås är en avfallseldad CFB-panna med bränsleeffekt på omkring 170 MW, vilket motsvarar omkring 50 ton avfall per timme. På den tillhörande bränsleberedningen produceras avfallsbränsle, RDF, i tre beredningslinjer genom att avfallet krossas och olika typer av inert material avskiljs och bildar rejekt från anläggningen.  Magnetisk metall avskiljs med magnetavskiljare, icke-magnetisk metall avskiljs med virvelströmsavskiljare och en tungfraktion bestående av bland annat sten och glas avskiljs med vindsikt. Kvaliteten på avskiljningen är dock bristfällig vilket leder till högt innehåll av inert material i bränslet och högt innehåll av brännbart material i de avskilda fraktionerna. Dessa två problem orsakar kostnader och miljöpåverkan som skulle kunna minskas.

    Syftet med detta examensarbete var att undersöka vilka faktorer som påverkar avskiljningen av inert material från avfallsbränsle för förbränning i fluidbäddspanna samt ge förslag på åtgärder som kan leda till förbättrad avskiljning. Detta har undersökts genom en fältstudie på den aktuella bränsleberedningen. För att insamla kunskap om bränsleberedningsprocessen och problembilden genomfördes en kartläggning av avskiljningen. Utifrån detta identifierades faktorer som kan påverka avskiljningen.

    För att ytterligare undersöka vad som påverkar avskiljningsprocessen genomfördes ett antal provtagningar av avskiljningen. En anpassad metod för provtagning av kvaliteten på avskiljningen genom plockanalys togs fram. Sammanlagt genomfördes nio provtagningar under olika förutsättningar. En ny typ av vindsikt testades också för att undersöka hur en investering skulle kunna förbättra avskiljningen. Vindsikten testades utifrån två alternativ av placering.

    Utifrån resultatet av kartläggningen identifierades fem faktorer som tros påverka avskiljningen. Dessa faktorer är det inkommande avfallet och dess egenskaper, materialflödets storlek genom produktionslinjen, ojämnt materialflöde genom magnetavskiljaren, tillbakakastande turbulens i vindsikten och fastnande material på spjället i vindsikten. Resultatet från de genomförda provtagningarna av kvaliteten på avskiljningen bekräftar att det inkommande avfallet samt materialflödets storlek genom produktionslinjen tros ha stor påverkan på samtliga avskiljare.

    Då den nya typen av vindsikt testades för att placeras i beredningslinjen visades ingen utmärkande förbättring jämfört med de befintliga vindsiktarna. Då den testades som andra steget i en två-stegs vindsiktning visade däremot resultatet potential att uppnå förbättrad avskiljning. Resultatet visade att två-stegs vindsiktningen har potential att minska mängden tungfraktionsrejekt med cirka 30 – 50 %. Det inerta innehållet i utgående lättfraktion var dock 6 – 8 % vilket motsvarar en höjning av det inerta innehållet i den totala mängden RDF på cirka 0,5 procentenheter. Dock medför en två-stegs vindsiktning att mer material kan siktas ut i vindsiktarna i beredningslinjerna vilket därmed skulle kunna ge en minskning av den totala mängden inert material i RDF. Som slutsats dras att investeringen i ny vindsikt för att skapa en två-stegs vindsiktning skulle kunna ge förbättrad avskiljning. Den nya vindsikten kan med fördel efterföljas av ytterligare avskiljning eftersom mängden inert material i RDF är relativt koncentrerat där. Dock bör en vidare utredning om kostnader och besparingspotential genomföras innan investeringen kan föreslås som åtgärd.

    Två typer av enklare konstruktioner föreslås för att åtgärda tre av de faktorer som identifierats. En konstruktion för att jämna ut materialflödet innan magnetavskiljaren samt en konstruktion för att förändra luftflödet i vindsikten.

    Att minska materialflödet genom linjerna föreslås som en viktig åtgärd för att förbättra avskiljningen. Detta kan åstadkommas genom att fördela RDF-produktionen så jämnt som möjligt på produktionslinjerna samt att sprida ut produktionen jämnt över tid. Detta kräver en mer aktiv planering av produktionen samt minimering av stopptider.

    En viktig slutsats som har dragits är att det inkommande avfallet varierar kraftigt och har stor inverkan på avskiljningsprocessen. En åtgärd som föreslås för att ge förbättrad avskiljning är att en regelbunden kontroll och variation av processen bör införas. Detta föreslås ske genom uttag och kontroll av RDF och rejekt från beredningslinjerna tillsammans med en bedömning av det inkommande avfallet. Informationen bör sedan ligga till grund för ett beslut om hur processen ska styras för att säkerställa en stabil kvalitet på avskiljningen.

     

    Fulltekst (pdf)
    fulltext
  • 23.
    Andersson, Stephanie
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Återvinning av solcellsmoduler i Sverige: En undersökning av de energitekniska, ekonomiska och politiska förutsättningarna2021Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The solar industry is one of the fastest-growing energy industries in the global market. The reason is a combination of the falling prices of modules and inverters and increased conversion to fossil-free energy production. When a photovoltaic module reaches the end of its life it needs to be replaced and discarded, which can create a sustainability problem depending on how this is managed. Today, less than 10% of the global photovoltaic waste is recycled. Only the European Union has implemented photovoltaic waste regulations in the form of the WEEE Directive, which requires that 85% of the waste is collected and at least 80% of waste collected must be prepared for reuse or recycling. This master thesis examines the energy technical, economic, and political conditions for a Swedish photovoltaic recycling plant. This is done through a literary study that is enhanced with calculations of future potential waste volumes and their economic value. As an alternative to a Swedish plant, the energy consumption for transporting waste to existing recycling plants in Europe is evaluated. The photovoltaic technologies included in this work are silicon-based mono-and polycrystalline modules, cadmium tellurium (CdTe) and copper indium gallium selenide (CIGS). Based on the calculations and the literature study, the energy technical conditions are good and not a barrier for a potential facility, the political conditions are deficient, and regulations need further development. The economic conditions constitute the largest barrier as waste volumes are not large enough for a Swedish facility to be economically profitable until 2042. The energy consumption for transport to existing recycling plants in Europe was 22 MJ/module for silicon-based mono-and polycrystalline modules and 10 MJ/module for CdTe modules. Which is a good alternative to a Swedish plant as collection processes and recycling processes are already in place.

    Fulltekst (pdf)
    Återvinning av solcellsmoduler i Sverige: En undersökning av de energitekniska, ekonomiska och politiska förutsättningarna
  • 24. Andrén, Lars
    et al.
    Persson, Tomas
    Högskolan Dalarna, Energi och miljöteknik.
    Lennermo, Gunnar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Handbok för kombinerade sol- och biovärmesystem: Teknik - System - Ekonomi2012Rapport (Annet vitenskapelig)
    Abstract [sv]

    Handboken beskriver olika solfångarkonstruktioner och solvärmekretsens ingående komponenter och ger en grundlig inblick i ackumulatortankens konstruktion och funktion. I boken finns förslag på systemutformning, olika tekniska lösningar och hur systemen bör styras och regleras. Handboken beskriver i första hand utformning-lösning-styrning av kombinationen sol- och pelletsvärme, men tar även upp solvärme i kombination med vedpannor, värmedrivna vitvaror och värmepumpar. Värmesystem med vattenburen värme är utmärkta att kombinera med solvärme, men det är i de flesta fall enklare att få till bra lösningar vid nyinstallation, än vid komplettering av befintlig anläggning. När solvärme och pelletsvärme ska kombineras finns det många alternativ till systemutformning. Det är viktigt att vattenburna pelletssystem utformas korrekt och kombineras på rätt sätt med solvärme för att komforten ska bli hög och elanvändningen låg. Vattenmantlade pelletskaminer med ett vattenburet värmesystem är extra intressant i kombination med solvärme. När eldningen upphör i samband med att värmebehovet avtar kan solvärmen ta över. En generell slutsats är att konventionella svenska pelletspannor med inbyggd varmvattenberedning inte är lämpliga i kombination med solvärmesystem. Den typen av bränslepannor ger komplicerade systemlösningar, höga värmeförluster och det är svårt att åstadkomma en tillräckligt bra temperaturskiktning i ackumulatortanken om varmvattenberedning sker i pannan. Solvärme för varmvattenberedning kan vara ett enkelt och bra komplement till pelletskaminer som genererar varmluft. För solvärmesystem är det viktigt att kraftig temperaturskiktning erhålls när värmelagret laddas ur. Det betyder att ackumulatortankens (eller varmvattenberedarens) nedre vattenvolym ska kylas ner till temperaturer som ligger nära ingående kallvattentemperatur. Ackumulatortankens mellersta del bör kylas till samma temperatur som radiatorreturen. Vid design av solfångarkretsen måste överhettning och stagnation kunna klaras utan risk för glykolnedbrytning eller andra skador på värmebärare eller rörkrets (och andra komponenter i kretsen). Partiell förångning minskar risken för att glykolen skadas då solfångaren når höga stagnationstemperaturer. Solfångarens glykolblandning tillåts koka (förångas) på ett kontrollerat sätt så att endast ånga blir kvar i solfångaren. Vätskevolymen i solfångaren samlas upp i ett större expansionskärl och systemet återfylls när vätskan kondenserar. Dränerande solfångarsystem med enbart vatten är ett möjligt alternativ till konventionella solfångare. De kräver en större noggrannhet vid installationen, så att sönderfrysning undviks. Dränerande systemlösningar är relativt ovanliga i Sverige. Om solfångaren under senhöst-vinter-tidig vår kan arbeta med att förvärma kallvatten från 10 till 20 ºC erhålls en betydligt bättre verkningsgrad på solfångaren (och framför allt ökar värmeutbytet då drifttimmarna ökar väsentligt) än om radiatorreturen (som i bästa fall ligger på temperaturnivån 30 - 40 ºC) ska förvärmas. Därför bör radiatorreturen placeras en bra bit upp från botten i ackumulatortanken och tappvarmvattnet ska förvärmas i en slinga som börjar i tankens botten. Om det finns ett VVC-system måste systemet anslutas på ett speciellt sätt så att ackumulatortankens temperaturskiktning inte störs. En viktig parameter vid ackumulatortankens utformning är att värmeförlusterna hålls låga. Det är viktigt för att klara tappvarmvattenlasten med solvärme under mulna perioder sommartid (men också för att hålla energianvändningen låg). I moderna hus, där ackumulatortanken i regel placeras i bostaden, blir det en komfortfråga att undvika övertemperaturer i det rum där värmelagret placeras. En bra standard på isoleringen (med minimerade värmeförluster) kräver att det finns ett lufttätt skikt över hela isoleringen som dessutom sluter tätt mot röranslutningar. Ofrivillig självcirkulation i anslutande kretsar som kan kyla av och blanda om ackumulatortankens vattenvolym, bör förhindras med backventiler och nedböjning av rören i isolerskiktet eller direkt utanför tanken.

    Fulltekst (pdf)
    FULLTEXT01
  • 25.
    Ariadi, B. Y.
    et al.
    Department of Agribusiness, University of Muhammadiyah Malang, Indonesia.
    Relawati, R.
    Department of Agribusiness, University of Muhammadiyah Malang, Indonesia.
    Rozaki, Z.
    Department of Agribusiness, University of Muhammadiyah Yogyakarta, Jl. Brawijaya, Kasihan, Bantul, Yogyakarta, Indonesia.
    Rahmawati, N.
    Department of Agribusiness, University of Muhammadiyah Yogyakarta, Jl. Brawijaya, Kasihan, Bantul, Yogyakarta, Indonesia.
    Jani, Yahya
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Al Zarliani, W. O.
    Department of Agribusiness, University of Muhammadiyah Buton, Jl. Betoambari No. 36, Sulawesi Tenggara, Baubau, Indonesia.
    Risk Analysis of Rice Farming at Volcano Semeru Area, Pronojiwo District, Lumajang Regency, Indonesia2024Inngår i: BIO Web of Conferences, EDP Sciences , 2024, Vol. 104, artikkel-id 00004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study aimed to analyze the production and financial risks of paddy rice farming in Pronojiwo district, Lumajang Regency, East Java, Indonesia. The research was conducted in March to May 2021, after the case of Semeru eruption in December 2020. The villages sample were Oro-Oro Ombo and Supiturang, the two most affected by the Mount Semeru lava flow. Primary data were obtained from the amount of 95 respondents chosen randomly. The risk of production and financial were analyzed by Coefficient of Variation (CV). Meanwhile, the factors affecting farm risk is analyzed by using regression method. The result of production risk on paddy rice farming in Pronojiwo, Lumajang Regency shows a low risk, namely indicated by CV of 35.38 %. However, the farm income risk is much higher, indicated by CV of 79.08 %. The factors affecting production risk is usage of chemical fertilizer. The increased number of chemical fertilizer will increase production risk of rice farming.

  • 26.
    Arul, A.J.
    et al.
    Indira Gandhi Ctr. for Atom. Res., Kalapakkam, India.
    Chandran, Kumar
    AERB-Safety Research Institute, Kalpakkam 603 102, India.
    Marimuthu, S.
    Indira Gandhi Ctr. for Atom. Res., Kalapakkam, India.
    Singh, O.P.
    Indira Gandhi Ctr. for Atom. Res., Kalapakkam, India.
    The power law character of off-site power failures2003Inngår i: Annals of Nuclear Energy, ISSN 0306-4549, Vol. 30, nr 14, s. 1401-1408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A study on the behavior of off-site AC power failure recovery times at three nuclear plant sites is presented. It is shown, that power law is appropriate for the representation of failure frequency–duration correlation function of off-site power failure events, based on simple assumptions about component failure and repair rates. It is also found that the annual maxima of power failure duration follow Frechet distribution, which is a type II asymptotic distribution, strengthening our assumption of power law for the parent distribution. The extreme value distributions obtained are used for extrapolation beyond the region of observation.

  • 27.
    Arul, A.J
    et al.
    Indira Gandhi Centre for Atomic Research, Kalpakkam, India.
    Chandran, Senthil Kumar
    AERB-Safety Research Institute, IGCAR Campus, Kalpakkam, India.
    Athmalingam, S.
    Indira Gandhi Centre for Atomic Research, Kalpakkam, India .
    Singh, O.P.
    Atomic Energy Regulatory Board, Niyamak Bhavan, Anushaktinagar, Mumbai, India .
    Suryaprakasa Rao, K.
    Department of Industrial Engineering, Anna University, Chennai, India .
    Reliability analysis of safety grade decay heat removal system of Indian prototype fast breeder reactor2006Inngår i: Annals of Nuclear Energy, ISSN 0306-4549, Vol. 33, nr 2, s. 180-188Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The 500MW Indian pool type Prototype Fast Breeder Reactor (PFBR), is provided with two independent and diverse Decay Heat Removal (DHR) systems viz., Operating Grade Decay Heat Removal System (OGDHRS) and Safety Grade Decay Heat Removal System (SGDHRS). OGDHRS utilizes the secondary sodium loops and Steam–Water System with special decay heat removal condensers for DHR function. The unreliability of this system is of the order of 0.1–0.01. The safety requirements of the present generation of fast reactors are very high, and specifically for DHR function the failure frequency should be less than 1E-7/ry. Therefore, a passive SGDHR system using four completely independent thermo-siphon loops in natural convection mode is provided to ensure adequate core cooling for all Design Basis Events. The very high reliability requirement for DHR function is achieved mainly with the help of SGDHRS. This paper presents the reliability analysis of SGDHR system. Analysis is performed by Fault Tree method using "CRAFT" software developed at Indira Gandhi Centre for Atomic Research. This software has special features for compact representation and CCF analysis of high redundancy safety systems encountered in nuclear reactors. Common Cause Failures (CCF) are evaluated by beta-factor method. The reliability target for SGDHRS arrived from DHR reliability requirement and the ultimate number of demands per year (7/y) on SGDHRS is that the failure frequency should be <=1.4E-8/de. Since it is found from the analysis that the unreliability of SGDHRS with identical loops is 5.2E-6/de and dominated by leak rates of components like AHX, DHX and sodium dump and isolation valves, options with diversity measures in important components were studied. The failure probability of SGDHRS for a design consisting of 2 types of diverse loops (Diverse AHX, DHX and sodium dump and isolation valves) is 2.1E-8/de, which practically meets the reliability requirement.

  • 28.
    Ashraf, Waqar Muhammad
    et al.
    Energy Pvt Ltd Sahiwal Coal Power Complex, Huaneng Shandong Ruyi Pakistan, Sahiwal 57000, Punjab, Pakistan.
    Rafique, Yasir
    Univ Engn & Technol, Dept Mech Engn, Taxila 47080, Punjab, Pakistan.
    Uddin, Ghulam Moeen
    Univ Engn & Technol, Dept Mech Engn, Lahore 54890, Punjab, Pakistan.
    Riaz, Fahid
    Natl Univ Singapore, Dept Mech Engn, Singapore 117575, Singapore.
    Asim, Muhammad
    Univ Engn & Technol, Dept Mech Engn, Lahore 54890, Punjab, Pakistan.
    Farooq, Muhammad
    Univ Engn & Technol, Dept Mech Engn, Lahore 54890, Punjab, Pakistan.
    Hussain, Abid
    Univ Engn & Technol, Dept Mech Engn, Taxila 47080, Punjab, Pakistan.
    Salman, Chaudhary Awais
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Artificial intelligence based operational strategy development and implementation for vibration reduction of a supercritical steam turbine shaft bearing2022Inngår i: Alexandria Engineering Journal, ISSN 1110-0168, E-ISSN 2090-2670, Vol. 61, nr 3, s. 1864-1880Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The vibrations of bearings holding the high-speed shaft of a steam turbine are critically controlled for the safe and reliable power generation at the power plants. In this paper, two artificial intelligence (AI) process models, i.e., artificial neural network (ANN) and support vector machine (SVM) based relative vibration modeling of a steam turbine shaft bearing of a 660 MW supercritical steam turbine system is presented. After extensive data processing and machine learning based visualization tests performed on the raw operational data, ANN and SVM models are trained, validated and compared by external validation tests. ANN has outperformed SVM in terms of better prediction capability and is, therefore, deployed for simulating the constructed operating scenarios. ANN process model is tested for the complete load range of power plant, i.e., from 353 MW to 662 MW and 4.07% reduction in the relative vibration of the bearing is predicted by the network. Further, various vibration reduction operating strategies are developed and tested on the validated and robust ANN process model. A selected operating strategy which has predicted a promising reduction in the relative vibration of bearing is selected. In order to confirm the effectiveness of the prediction of the ANN process model, the selected operating strategy is implemented on the actual operation of the power plant. The resulting reduction in the relative vibrations of the turbine's bearing, which is less than the alarm limit, are confirmed. This cements the role of ANN process model to be used as an operational excellence tool resulting in vibration reduction of high-speed rotating equipment. (c) 2021 THE AUTHORS. Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

  • 29.
    Aslanidou, Ioanna
    Mälardalens universitet, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Micro Gas Turbines - Trends and Opportunities2022Inngår i: Mechanical engineering (New York, N.Y. 1919), ISSN 0025-6501, E-ISSN 1943-5649, Vol. 61, nr 3, s. 58-60Artikkel i tidsskrift (Fagfellevurdert)
  • 30.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Rahman, Moksadur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zaccaria, Valentina
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Micro Gas Turbines in the Future Smart Energy System: Fleet Monitoring, Diagnostics, and System Level Requirements2021Inngår i: Frontiers in Mechanical Engineering, E-ISSN 2297-3079, Vol. 7, artikkel-id 676853Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The energy generation landscape is changing, pushed by stricter regulations for emissions control and green energy generation. The limitations of renewable energy sources, however, require flexible energy production sources to supplement them. Micro gas turbine based combined heat and power plants, which are used for domestic applications, can fill this gap if they become more reliable. This can be achieved with the use of an engine monitoring and diagnostics system: real-time engine condition monitoring and fault diagnostics results in reduced operating and maintenance costs and increased component and engine life. In order to allow the step change in the connection of small engines to the grid, a fleet monitoring system for micro gas turbines is required. A proposed framework combines a physics-based model and a data-driven model with machine learning capabilities for predicting system behavior, and includes a purpose-developed diagnostic tool for anomaly detection and classification for a multitude of engines. The framework has been implemented on a fleet of micro gas turbines and some of the lessons learned from the demonstration of the concept as well as key takeaways from the general literature are presented in this paper. The extension of fleet monitoring to optimal operation and production planning in relation to the needs of the grid will allow the micro gas turbines to fit in the future green energy system, connect to the grid, and trade in the energy market. The requirements on the system level for the widespread use of micro gas turbines in the energy system are addressed in the paper. A review of the current solutions in fleet monitoring and diagnostics, generally developed for larger engines, is included, with an outlook into a sustainable future.

  • 31.
    Aslanidou, Ioanna
    et al.
    Mälardalens universitet, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Soibam, Jerol
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Comparison of machine learning approaches for spectroscopy applications2022Inngår i: Proceedings of the 63rd International Conference of Scandinavian Simulation Society / [ed] Lars O. Nord; Tiina Komulainen; Corinna Netzer; Gaurav Mirlekar; Berthe Dongmo-Engeland; Lars Eriksson, 2022, s. 80-85Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In energy production the characterization of the fuel is a key aspect for modelling and optimizing the operation of a power plant. Near-infrared spectroscopy is a wellestablished method for characterization of different fuels and is widely used both in laboratory environments and in power plants for real-time results. It can provide a fast and accurate estimate of key parameters of the fuel, which for the case of biomass can include moisture content, heating value, and ash content. These instruments provide a chemical fingerprint of the samples and require a calibration model to relate that to the parameters of interest.

    A near-infrared spectrometer can provide point data whereas a hyperspectral imaging camera allows the simultaneous acquisition of spatial and spectral information from an object. As a result, an installation above a conveyor belt can provide a distribution of the spectral data on a plane. This results in a large amount of data that is difficult to handle with traditional statistical analysis. Furthermore, storage of the data becomes a key issue, therefore a model to predict the parameters of interest should be able to be updated continuously in an automated way. This makes hyperspectral imaging data a prime candidate for the application of machine learning techniques. This paper discusses the modelling approach for hyperspectral imaging, focusing on data analysis and assessment of machine learning approaches for the development of calibration models.

  • 32.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zaccaria, Valentina
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Pontika, E.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Zimmerman, Nathan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kalfas, A. I.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Teaching gas turbine technology to undergraduate students in Sweden2018Inngår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME) , 2018, Vol. 6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses the teaching of gas turbine technology in a third-year undergraduate course in Sweden and the challenges encountered. The improvements noted in the reaction of the students and the achievement of the learning outcomes is discussed. The course, aimed at students with a broad academic education on energy, is focused on gas turbines, covering topics from cycle studies and performance calculations to detailed design of turbomachinery components. It also includes economic aspects during the operation of heat and power generation systems and addresses combined cycles as well as hybrid energy systems with fuel cells. The course structure comprises lectures from academics and industrial experts, study visits, and a comprehensive assignment. With the inclusion of all of these aspects in the course, the students find it rewarding despite the significant challenges encountered. An important contribution to the education of the students is giving them the chance, stimulation, and support to complete an assignment on gas turbine design. Particular attention is given on striking a balance between helping them find the solution to the design problem and encouraging them to think on their own. Feedback received from the students highlighted some of the challenges and has given directions for improvements in the structure of the course, particularly with regards to the course assignment. This year, an application developed for a mobile phone in the Aristotle University of Thessaloniki for the calculation of engine performance will be introduced in the course. The app will have a supporting role during discussions and presentations in the classroom and help the students better understand gas turbine operation. This is also expected to reduce the workload of the students for the assignment and spike their interest.

  • 33.
    Aslanidou, Ioanna
    et al.
    Cranfield University, United Kingdom.
    Zachos, Pavlos K.
    Cranfield University, United Kingdom.
    Pachidis, Vassilios
    Cranfield University, United Kingdom.
    Singh, Riti
    Cranfield University, United Kingdom.
    A physically enhanced method for sub-idle compressor map generation and representation2010Inngår i: Proceedings of the ASME Turbo Expo, Glasgow, United Kingdom, 2010Konferansepaper (Fagfellevurdert)
  • 34.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Process Modeling of Combustion and Digesters for On-line Applications2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The use of biomass has increased in recent years due to the efforts to reduce the high emissions of greenhouse gases, primarily carbon dioxide from combustion of fossil fuels. At the same time industrial processes have become more complex because of increased production rates and profitability requirements. A higher degree of automation is needed when the processes are too complex to be handled manually. There is a need to find modeling strategies that can automatically handle the challenges that the conversion of biomass in an industrial process entails, such as operational changes, decreasing component and overall system efficiency, drifting sensors, etc. The objective of this thesis is to develop a methodology for on-line applications in industrial processes. Dynamic process models have been developed for continuous digesters and boilers. Process models have been evaluated for their use in continuous industrial process. Applications that have been studied are monitoring and diagnostics, advanced control and decision support. The process models are designed for on-line simulations. The results shows that the use of mathematical simulation models can improve the use of both process data and process understanding, to achieve improved diagnostics, advanced control and process optimization. In the two examples of industrial processes covered in this thesis, we can see that similar types of models can be used for completely different types of processes, such as pulp digesters and boilers. It also demonstrates the ability to combine soft sensors and hard sensors with physical models to take the information to a higher level of utilization.

    Fulltekst (pdf)
    fulltext
  • 35.
    Avelin, Anders
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Effect of different renovation actions, their investment cost and future potential2017Inngår i: Energy Procedia, ISSN 1876-6102, Vol. 143, s. 73-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    65% of the buildings in Västerås, situated in the region of Mälardalen, Sweden were built before 1970. It is thus time for renovation. The situation is the same in most cities in Sweden and Northern Europe. The depth of renovation can be quite different. In this paper we evaluate some examples where cost is compared to energy saving effect. How to plan renovation to make use of the available capital in the cities is discussed. As a complement to direct renovation actions also behavior change with respect to energy is discussed and exemplified. The cost for energy actions in relation to other renovation aspects is discussed especially for the passive house case in Allingsås, Sweden. The passive house center calculate an extra cost for passive house standard to be 10 000 €/apartment while an external consultant has the figure 40 000 € of the total cost of 120 000 €. With this space heating can be 18 kWh/m2.year, or a reduction by 84 % with respect to space heating and 62% for overall heat and hot water demand. If you use the latter cost figure passive house standard is not motivated from an energy savings perspective while if using the lower figure it is very interesting. For the other less deep renovations we see that adding more insulation and three glass windows is motivated if the degradation has been strong, while a simpler renovation may be ok if the outer surface coating is not too bad. For these less deep renovations we see cost figures of 65 €/m2 respectively 28 €/m2 with reduction of heating and hot water demand of 56 % respectively 34 %. 

  • 36.
    Avelin, Anders
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aulin, Robert
    Swedish University of Agricultural Sciences, Sweden.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Forest biomass for bioenergy production – comparison of different forest species2014Inngår i: / [ed] J. Yan, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Forest biomass is a renewable and sustainable source of energy that can be used for producing electricity, heat, and biofuels. The production of biomass for energy is considered to be an important step in developing sustainable communities and managing greenhouse gas emissions effectively. Biomass properties vary and are commonly associated with plant species. Hence, efficient methods to predict biofuel characteristics will greatly affect the utilization and management of feedstock production. In this paper attempt was made to correlate various chemical characteristics with NIR spectra. Wood chips from various plant species was analyzed for lignin content, heating value, ash content and NIR and the results were evaluated with correlation, PCA and PCR. Initial evaluation showed promising results where chemical components in the wood correlate to NIR spectra. A selection of results will be presented in this paper. Further analysis as well as results from PCA and PCR models will be presented in the full paper version.

    Fulltekst (pdf)
    fulltext
  • 37.
    Avelin, Anders
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Widarsson, Björn
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Lilja, Reijo
    VTT, Espoo, Finland.
    Time based data reconciliation and decision support for a CFB boiler2009Inngår i: IFAC Proceedings Volumes (IFAC-PapersOnline), 2009 / [ed] Yrjö Majanne, Tampere: Tampere University Press , 2009, s. 338-343Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper covers a method for operator decision support, where physical simulation models are used to connect different physical variables to each other. By comparing energy and material balances for a larger process area inconsistencies in single process parts and sensor measurements can be detected, by following the development between single measurements and values predicted from the simulations. This information then can be used as input to e.g. a BN, Bayesian Network, for decision support. The application has been for a CFB boiler at Mälarenergi AB. The simulators have been made in Modelica respectively a more advanced model in APROS.

  • 38.
    Azaza, Maher
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tunis El Manar University, Tunis, Tunisia.
    Tanougast, C.
    Lorraine University, France.
    Fabrizio, E.
    University of Torino, Grugliasco, Italy.
    Mami, A.
    Tunis El Manar University, Tunis, Tunisia .
    Smart greenhouse fuzzy logic based control system enhanced with wireless data monitoring2016Inngår i: ISA transactions, ISSN 0019-0578, E-ISSN 1879-2022, Vol. 61, s. 297-307Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Greenhouse climate control is complicated procedure since the number of variables involved on it and which are dependent on each other. This paper presents a contribution to integrate greenhouse inside climate keys parameters, leading to promote a comfortable micro-climate for the plants growth while saving energy and water resources. A smart fuzzy logic based control system was introduced and improved through specific measure to the temperature and humidity correlation. As well, the system control was enhanced with wireless data monitoring platform for data routing and logging, which provides real time data access. The proposed control system was experimentally validated. The efficiency of the system was evaluated showing important energy and water saving.

  • 39.
    Azimoh, C. L.
    et al.
    University of Johannesburg, Department of Quality and Operations Management, Faculty of Engineering and Built Environment, Johannesburg, South Africa.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mbohwa, C.
    University of Johannesburg, Department of Quality and Operations Management, Faculty of Engineering and Built Environment, Johannesburg, South Africa.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Replicability and scalability of mini-grid solution to rural electrification programs in sub-Saharan Africa2017Inngår i: Renewable Energy, ISSN 0960-1481, Vol. 106, s. 222-231Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The assessment of off-grid electrification programs in developing countries largely based on mini-grid and solar home system (SHS) has shown that they are faced with low development imparts and sustainability challenges, which has resulted in failure of many projects. This study provides solutions on how to surmount these challenges, leaning on the experience of a hybrid solar-diesel mini-grid at Tsumkwe village in Namibia. It provides analyses of a case study based on empirical evidence from field studies, interviews of representatives of households, public institutions and energy providers. In addition, it investigates the technical challenges and economic impacts of the electrification program. HOMER™ and MATLAB™ models were used in the analysis and investigations. The findings show that despite the challenges, the system has been sustained because it keyed into an existing structure with growth potentials. The progressive tariff system adopted by the government helped to cushion costs and allow low income households in the energy matrix. Adoption of strict maintenance measures, and implementation of energy efficiency measures prior to the commissioning of the program, resulted in the reduction of costs. The success elements identified in this study could be extrapolated in other sub-Saharan African countries if the challenges are properly addressed.

  • 40.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Illuminated but not electrified: An assessment of the impact of Solar Home System on rural households in South Africa2015Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 155, s. 354-364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The introduction of the off-grid electrification program in South Africa using the Solar Home System (SHS) was a central component of the government policy aimed at bringing development to un-electrified households. An assessment of the performance of SHS in many countries provided little evidence to support the development impact of the system. The general perception is that the SHS program is wasting government funds and has no hope of achieving the set objectives. Previous scientific reports have concluded that SHS is the most viable technology for bringing about socio-economic development to rural households. Most of these conclusions have been based on one sided arguments and largely on anecdotal evidence. This study provides a pluralistic view of the subject from the perspective of the energy service companies (ESCOs) and the households using the equipment. The development impact of SHS is subjected to scientific analysis by investigating the economic and social dimensions of the program. Additionally, the sustainability of the South African SHS program is assessed by investigating the challenges facing the ESCOs and the households. The study reveals that illumination provided by SHS electricity has profound impact on the livelihoods of rural households. Due to the limited capacity of SHS for productive and thermal use, there are limited direct economic benefits to the households. The associated economic impact is peripheral to the secondary usage of SHS electricity. SHS has improved the productivity of small scale business owners who utilize the light from SHS to do business at night. Irregularities in payment of subsidy funds and energy bills, high operation cost, non-optimal use of SHS, grid encroachment, and lack of customer satisfaction contribute to make the business unsustainable for the ESCOs.

    Fulltekst (pdf)
    fulltext
  • 41.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The burden of shading and location on the sustainability of South African solar home system program2015Inngår i: Energy Procedia, ISSN 1876-6102, Vol. 75, s. 308-313Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most contributions on the issues of sustainability of rural electrification projects have focused on the technology and business models used to drive the projects. The issues of user education and environmental impact on the technology have received little attention, despite the fact that these challenges affect lives of projects after commissioning. The usage pattern of solar home systems (SHS) by most users that placed their solar panels close to obstructing objects, results in shading of the panels, and geographic location of households in the concession areas of the South African SHS program affects the performances of the system. The non-optimal use of SHS is mainly due to lack of user education. Therefore this paper reports on the impact of geographic location and shading of panels on the economics and technical performance of SHS. The study was done by investigating the performance of 75 WP solar panels operated at two sites in South Africa (Upington in Northern Cape Province and Thlatlaganya in Limpopo Province), the performance of an optimized shaded SHS and a non-shaded one was also investigated. The results show that both geographic location and shading compromise the performance of the systems, the energy output of a solar panel located at Upington is increased by 19% and the state of charge of the battery (SOC) increased by 6%, compared to the panel situated at Thlatlaganya village. Also the life span of the battery is increased by about one year. The SOC of the partially shaded SHS is reduced by 22% and loss of power to the load increased by 20%. The geographical location of the SHS concession areas in South Africa and lack of adherence to the manufacturer's installation specification affects the economics of SHS and the energy output vis-a-vis the sustainability of the program due to reduction in life cycle of the batteries. 

  • 42.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An assessment of unforeseen losses resulting from inappropriate use of solar home systems in South Africa2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, s. 336-346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the challenges to the sustainability of the Solar Home System (SHS) electrification program in South Africa is equipment theft. In response to this, communities susceptible to solar panel theft resort to mounting their panels flat on the ground so they can be looked after during the day and taken indoors at night for safe keeping. Other households use their security lights to illuminate their environment and provide security for pole and roof mounted solar panels at night. These actions have consequential effects on the performance of the SHS. Several studies have detected resentment from households regarding the low power quality from these systems. Most scientific contributions on the issue of low power from SHS have focused on the challenges based on the technical designs of the systems. The power losses due to the usage pattern of the system has not received much attention. This study therefore reports on the technical losses as a result of the deviation from the designed and installed specification of the system by the users in order to protect their systems. It also investigates the linkage between the technical and economic losses which affects the sustainability of SHS program. A case study was performed in Thlatlaganya village within Limpopo province in South Africa. Technical analysis using PVSYST solar software revealed that the energy output and performance of the battery is compromised as a result of these practices. Economic analysis indicates that the battery life and the economics of owning and operating SHS are affected negatively. The study recommends solutions to mitigate these losses, and proposes a cost effective way of optimizing the operation of SHS using a Bench-Rack system for mounting solar panels.

    Fulltekst (pdf)
    fulltext
  • 43.
    Baheta, Aklilu
    et al.
    Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak, Malaysia.
    Sidahmed, Mojahid
    Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak, Malaysia.
    Suleiman, Shaharin
    Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak, Malaysia.
    Fentaye, Amare Desalegn
    Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak, Malaysia.
    Syed, Gilani
    Petronas Carigali Sdn Bhd. Kertih, Terengganu, Malaysia.
    DEVELOPMENT AND VALIDATION OF A TWIN SHAFT INDUSTRIAL GAS TURBINE PERFORMANCE MODEL2016Inngår i: Journal of Engineering and Applied Sciences, E-ISSN 1819-6608, Vol. 22, nr 11, s. 13365-13371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gas turbine performance is very responsive to ambient and operational conditions. If the engine is not operating atits optimum conditions, there will be high energy consumption and environmental pollution. Hence, a precise simulationmodel of a gas turbine is needed for performance evaluation and fault detection and diagnostics. This paper presents a twinshaft industrial gas turbine modeling and validation. To develop the simulation model component maps are important,however they are property of the manufacturers and classified documents. In this case, known the compressor pressureratio, speed, and flow rate, the missing design parameters, namely turbines inlet temperatures and pressure ratios werepredicted using GasTurb simulation software. Once the design parameters are developed, the nearest compressor andturbine maps were selected from GasTurb map collection. Beta lines were introduced on each map so that the exactcorresponding value can be picked for a given two parameters of a given map. After the completion of components model,a simulation model was developed in Matlab environment. The equations governing the operation of individual componentwere solved using iteration method. The simulation model has modular nature; it can be modified easily when a change isrequired. The parameters that the model can predict include terminal temperature and pressure, flow rate, specific fuelconsumption, thermal efficiency and heat ratio. To demonstrate the validity of the developed model, the performance ofGE LM2500 twin shaft gas turbine operating in a gas oil industry at Resak PETRONAS platform in Malaysia waspredicted and compared with operational data. The results showed that an average of 5, 3.8 and 3.7 % discrepancies forcompressor discharge temperature and pressure, and fuel flow rate, respectively. This comparison of results showed goodagreement between the measured and predicted parameters. Thus, the developed model can be helpful in performanceevaluation of twin shaft gas turbines and generation of data for training and validation of a fault detection and diagnosticmodel.

  • 44.
    Bai, Fan
    et al.
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian 710049, Shaanxi, Peoples R China..
    Lei, Le
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Zhang, Zhuo
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Chen, Li
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Dai, Yan-Jun
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Chen, Lei
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Tao, Wen-Quan
    Xi An Jiao Tong Univ, Key Lab Thermofluid Sci & Engn MOE, Xian, Shaanxi, Peoples R China..
    Application of similarity theory in modeling the output characteristics of proton exchange membrane fuel cell2021Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 46, nr 74, s. 36940-36953Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proton Exchange Membrane Fuel Cell (PEMFC) has attracted widespread interest. In the present work, similarity analysis is adopted for a three-dimensional single-phase isothermal model of PEMFC to derive similarity criteria. Seven kinds of input criteria (Pi(1) similar to Pi(7)) are obtained, relevant to the fluid flow, pressure drop, flow resistance in a porous medium, activity loss, diffusion mass transfer, convective mass transfer and ohmic loss in PEMFC respectively. Dimensionless voltage and dimensionless current density are defined as two output criteria. Numerical verifications show that if the seven criteria keep their individual values with their components vary in a wide range, the dimensionless polarization curves keep the same with a deviation about 1%, showing the validity and feasibility of the present analysis. From the effect on the dimensionless polarization curve, sensibility analysis shows that the seven criteria can be divided into three categories: strong (Pi(4) and Pi(7), -94.9% similar to +349.2%), mild to minor (Pi(5) and Pi(6), -4.5% similar to +5.0%), and negligible (Pi(1), Pi(2) and Pi(3), -1.2% similar to +1.1%). The similarity analysis approach can greatly save computation time in modeling the output characteristics of PEMFC. (C) 2021 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.

  • 45.
    Bai, Q.
    et al.
    Xi'an Jiaotong University, Xi'an, China.
    Guo, Z.
    Xi'an Jiaotong University, Xi'an, China.
    Cui, X.
    Xi'an Jiaotong University, Xi'an, China.
    Yang, Xiaohu
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Xi'an Jiaotong University, Xi'an, China.
    Yanhua, L.
    Xi'an Jiaotong University, Xi'an, China.
    Jin, L.
    Xi'an Jiaotong University, Xi'an, China.
    Sun, Y.
    Xi'an Jiaotong University, Xi'an, China.
    Experimental investigation on the solidification rate of water in open-cell metal foam with copper fins2018Inngår i: Energy Procedia, Elsevier Ltd , 2018, s. 210-214Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study focused on the effect of inserting fins into metal foam on the solidification rate. To this aim, a well-designed experimental system with solid-liquid interface visualization was built. Metal foam samples with different fin intervals were prepared for experiments. Solidification process of water saturating in finned metal foam under bottom cooling was experimentally investigated. Results showed that inserting fins into metal foam can make a promotional improvement on solidification rate of water. The solid-liquid interface became curved after inserting fins, compared with metal foam sample without fins. Besides, changing the interval has little effect on the solidification rate.

  • 46.
    Bai, Q.
    et al.
    School of Human Settlements and Civil Engineering, Xi'An Jiaotong University, Xi'an, China.
    Guo, Z.
    School of Human Settlements and Civil Engineering, Xi'An Jiaotong University, Xi'an, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, Xiaohu
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jin, L.
    School of Human Settlements and Civil Engineering, Xi'An Jiaotong University, Xi'an, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Experimental investigation on the solidification behavior of phase change materials in open-cell metal foams2017Inngår i: Energy Procedia, ISSN 1876-6102, Vol. 142, s. 3703-3708Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presented an experimental investigation on solidification behavior of fluid saturated in highly porous open-cell copper foams. Particular attention has been made on the effect of pore parameters (pore density and porosity) on the solidification behavior. A purposely-designed apparatus was built for experimental observations. Results showed that the copper foam had a great effect on solidification and the full solidification time can be saved up to 50%, especially preventing the decrease in solidification rate during the later stage of phase change. The smaller the porosity is, the faster the solidification rate will be. Pore density was found to have little influence upon the solidification rate. In addition, the local natural convection does exist but it has a slight effect on solidification, leading to the slant of the solid-liquid interface. 

  • 47.
    Baig, M. M.
    et al.
    Data Science Team, Orion Health, Auckland, New Zealand.
    Gholam Hosseini, H.
    Auckland University of Technology, Auckland, New Zealand.
    Afifi, S.
    Auckland University of Technology, Auckland, New Zealand.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A systematic review of rapid response applications based on early warning score for early detection of inpatient deterioration2021Inngår i: Informatics for Health and Social Care, ISSN 1753-8157, E-ISSN 1753-8165, Vol. 46, nr 2, s. 148-157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim: The aim of this study was to investigate the effectiveness of current rapid response applications available in acute care settings for escalation of patient deterioration. Current challenges and barriers, as well as key recommendations, were also discussed. Methods: We adopted PRISMA review methodology and screened a total of 559 articles. After considering the eligibility and selection criteria, we selected 13 articles published between 2015 and 2019. The selection criteria were based on the inclusion of studies that report on the advancement made to the current practice for providing rapid response to the patient deterioration in acute care settings. Results: We found that current rapid response applications are complicated and time-consuming for detecting inpatient deterioration. Existing applications are either siloed or challenging to use, where clinicians are required to move between two or three different applications to complete an end-to-end patient escalation workflow–from vital signs collection to escalation of deteriorating patients. We found significant differences in escalation and responses when using an electronic tool compared to the manual approach. Moreover, encouraging results were reported in extensive documentation of vital signs and timely alerts for patient deterioration. Conclusion: The electronic vital signs monitoring applications are proved to be efficient and clinically suitable if they are user-friendly and interoperable. As an outcome, several key recommendations and features were identified that would be crucial to the successful implementation of any rapid response system in all clinical settings.

  • 48.
    Bales, Chris
    et al.
    Högskolan Dalarna, Energi och miljöteknik.
    Nielsen, Christian
    Högskolan Dalarna, Energi och miljöteknik.
    Peréz de la Mora, Nicolás
    SAMPOL Ingeniería y Obras / Palma de Mallorca (Spain).
    Sotnikov, Artem
    Vela Solaris AG, Winterthur (Switzerland).
    Louvet, Yoann
    FSAVE Solartechnik GmbH, Kassel (Germany).
    Bava, Federico
    Technical University of Denmark, Lyngby (Denmark).
    Shantia, Alireza
    University of Innsbruck, Innsbruck (Austria).
    Lennermo, Gunnar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. WSP, Gothenburg (Sweden).
    Seven Phd Studies on Solar District Heat2014Inngår i: Proceedings EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014, s. 652-661Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, three at universities and two at companies. In addition there is a seventh PhD in a Swedish national research school focused on energy efficiency within district heating networks (Reesbe). The initial work has concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 49.
    Bartusch, Cajsa
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Visualisering av elanvändning i flerbostadshus: Delrapport inom ELAN Etapp III2011Rapport (Annet vitenskapelig)
    Abstract [sv]

    Elanvändningen i våra bostäder sker utan närmare eftertanke och reflektion. Återkopplingen avseende hushållens individuella elanvändning är i det avseendet mycket betydelsefull. I dagsläget är dock den förbrukningsinformation som hushållen har tillgång till mycket begränsad, i synnerhet i flerbostadshus. Syftet med projektet Visualisering av elanvändning i flerbostadshus är att utveckla och utvärdera designkoncept för individuell återkoppling till hushåll som bor i lägenhet. Designkoncepten avser en portabel display, en webbaserad statistiktjänst samt grafisk förbrukningsinformation på elräkningen. Det övergripande målet med projektet är en minskad och mer medveten elanvändning i flerbostadshus.

    Utvecklingen omfattar displayens och statistiktjänstens funktioner och gränssnitt samt en ändamålsenlig formgivning av den grafiska återkopplingen på elräkningen. Utvärderingen omfattar de boendes användning och upplevelser av de produkter och tjänster som designkoncepten avser. Projektet genomförs i två etapper, varav den första omfattar utvecklingen av ovan nämnda designkoncept och den andra avser utvärderingen av desamma. Föreliggande rapport avser den första etappen, medan den andra redovisas i samband med slutrapporteringen av projektet.

    Fulltekst (pdf)
    fulltext
  • 50.
    Bartusch, Cajsa
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Visualisering av elanvändning i flerbostadshus: Slutrapport inom ELAN Etapp III2011Rapport (Annet vitenskapelig)
    Abstract [sv]

    Elanvändningen i våra bostäder sker vanligtvis utan närmare eftertanke och reflektion. Återkopplingen avseende hushållens individuella elanvändning är i den meningen mycket betydelsefull. I dagsläget är dock den förbrukningsinformation som hushållen har tillgång till mycket begränsad, i synnerhet i flerbostadshus. Syftet med projektet Visualisering av elanvändning i flerbostadshus har varit att utveckla och utvärdera designkoncept för individuell återkoppling till hushåll som bor i lägenhet. Designkoncepten avser en portabel display, en webbaserad statistiktjänst samt grafisk förbrukningsinformation på elräkningen. Det övergripande målet med projektet har varit att bidra till en mer medveten och därmed effektivare elanvändning i flerbostadshus.Utvecklingen har omfattat displayens och statistiktjänstens funktioner och gränssnitt samt en ändamålsenlig formgivning av den grafiska återkopplingen på elräkningen.

    Utvärderingen har omfattat de boendes användning och upplevelser av de produkter och tjänster som designkoncepten avser. Projektet har genomförts i två etapper, varav den första har omfattat utvecklingen av ovan nämnda designkoncept och den andra har avsett utvärderingen av desamma. Föreliggande rapport avser i första hand den andra etappen, medan resultaten av den första har redovisats i sin helhet i en tidigare delrapport; Elforsk rapport 08:18.

    Den trådlösa displayen tillhandahåller framför allt funktioner med mer eller mindre direkt återkoppling, medan statistiktjänsten och i synnerhet den grafiska förbrukningsinformationen i första hand avser uppföljning av den individuella elanvändningen med längre tidsperspektiv. Både displayen och statistiktjänsten erbjuder även möjligheten att göra jämförelser mellan olika tidsperioder och med liknande hushåll. Traditionella stapeldiagram i kombination med förtydligande färgsymbolik har visat sig vara mycket funktionella och har följaktligen använts i flertalet av designkonceptens gränssnitt. Enkelhet och lättillgänglighet har visat sig vara de viktigaste framgångsfaktorerna i samband med återkoppling till elanvändare.

    Den grafiska förbrukningsinformationen på elräkningen har framstått som viktigast i den bemärkelsen att den utgör den återkoppling som når i särklass flest elkonsumenter. Egenskaperna enkelhet och lättillgänglighet har därför en särskilt avgörande betydelse i det här sammanhanget. Ett förhållandevis avskalat designkoncept har således förordats för ändamålet grafisk förbrukningsinformation på fakturan. Tidsupplösningen motsvarar faktureringsperioderna och grafens staplar representerar med andra ord de faktiska och förväntade månadsförbrukningarna under innevarande år samt i jämförande syfte de faktiska månadsförbrukningarna under föregående år.

    Utvecklingen och utvärderingen av en portabel display har omfattat två olika designkoncept: Interactive Institute’s Energy AWARE Clock och ”Ingenjörsdisplayen”. Namnen härstammar från gränssnittens olika utformningar av förbrukningsinformationen, som i jämförande syfte har varit abstrakt men intuitivt tillgänglig respektive konkret och reell. De användartester som har genomförts i hemmiljö tyder därvidlag på att användarna föredrar en kombination av de båda designkoncepten. För en optimal användning av den här produkten krävs en central placering i hemmet, vilket innebär att yttre egenskaper såsom en tilltalande design har visat sig ha stor betydelse för användarna.Den webbaserade statistiktjänsten, som kallas Energiinfo™, utgör den återkoppling som tillhandahåller flest alternativa tidsupplösningar.

    Förbrukningsinformationen som tillhandahålls på månads- och årsbasis har emellertid visat sig vara bäst lämpade för kontroll och uppföljning av hushållets elanvändning, vilka utgör de vanligaste användningsområdena. Användarnas syften är dock för övrigt högst varierande och möjligheten att anpassa förbrukningsinformationen för deras individuella behov har därför visat sig vara mycket betydelsefull i det här sammanhanget.

    Samtliga designkoncept som studien avser har visat sig vara mer eller mindre ändamålsenliga i den bemärkelsen att de i viss mån bidrar till en ökad medvetenhet om hushållets egen elförbrukning samt ett förändrat beteende i syfte att effektivisera densamma. Inget av designkoncepten har dock framstått som viktigare än det andra i det avseendet, utan den förbrukningsinformation som de olika återkopplingsalternativen tillhandahåller kompletterar snarare varandra. Vidare har inget av designkoncepten visat sig vara idealiskt för uppdelningsåterkoppling, vilket innebär information om hur mycket olika hushållsapparater bidrar till den totala elkonsumtionen och tenderar att vara den förbrukningsinformation som hushållen har störst behov av.

    Fulltekst (pdf)
    fulltext
1234567 1 - 50 of 1091
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