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  • 201.
    Ghaviha, Nima
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Holmberg, C.
    Bombardier Transportation, Västerås, Sweden.
    Bohlin, M.
    RISE SICS, Västerås, Sweden.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Modeling of Losses in the Motor Converter Module of Electric Multiple Units for Dynamic Simulation Purposes2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 2303-2309Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Simulation of power consumption in electric trains is categorized in two categories: electrical power simulation and mechanical power simulation. The mechanical power is calculated as speed times tractive effort and it gives an overall view on the total energy consumption of the train during different driving cycles. Detailed calculation of losses in different components in the propulsion system is however done using complex electrical models. In this paper, we introduce a nonlinear regression model generated from validated electrical equations for the calculation of the power loss in the motor converter module of electric trains. The function can be used instead of efficiency maps to evaluate the trains’ performance during the operation or dynamic simulations.

  • 202.
    Gholinejad, Hassan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mousavi Takami, Kourosh
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Estimation of electricity losses by numerical approach to present a solution for losses reduction2014Ingår i: International Journal of Advanced Engineering Applications, ISSN 2321-7723, Vol. 7, nr 4, s. 30-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electricity losses are one of the big anxieties for utilities. Electricity loss in Iran network according to Tavanir report is over 15% but individual researchers have different comments. Also, the lack of sufficient information is a network problem. To overcome on the problems authors used Top-Down/Bottom-Up method to estimate of losses in Iran’s electricity network. To achieve the model, at a certain moment measurements of input complex power in the feeder and voltages in the farthest network node and power flow calculation has been done. Using the estimated losses, authors suggest a strategy to losses reduction in every different part of distribution networks. Due to different culture, climate and network topology, losses are different and separate solution is needed. Proposed method was carried out by performing tests on a feeder with 88+35 nodes according to the IEEE 123 node test feeder. An economical investigation showed the benefits for utilities and improved the proposed plan. The main innovation in the presented paper is to combine a forecasting approach with experimental data to define a model for networks with unknown parameters.

  • 203.
    Gholinejad, Hassan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mousavi Takami, Kourosh
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mousavi Takami, Amin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    To promote electricity smart grid performances by numerical modeling applications2014Ingår i: Proceedings of the 55th Conference on Simulation and Modelling(SIMS 55): “Modelling, Simulation and Optimization” / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping: Linköping University Electronic Press, 2014, s. 347-355Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wide world’s utilities are generating, transmitting and distributing of electricity throughout the country andare responsible to its quality.Distributed automated distribution system has been proposed for planning to reduce losses, optimize capacityand load balancing in electricity networks. The world electricity average loss is about and outage percustomer time is about min/ year. The indices are needed to optimize in developing countries.This paper deals on a modeled distribution system in Sari distribution region and evaluates three mentionedparameters on network quality. Restoration, maneuvers to achieve the minimum loss, reactive powercontrolling, load balancing etc are investigated.Modeling performs by MATLAB software, EMTP for transient modeling and Digsilent with real data bySari Distribution Company. In this paper, a new approach by rearrangement aimed at reducing losses andimproving of load balancing in distribution networks was presented.

    Keywords: Modelling, smart grid, electricity network

  • 204.
    Gibrael, Nemir
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hassan, Hamse
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    HYDROGEN-FIRED GAS TURBINE FOR POWER GENERATION WITH EXHAUST GAS RECIRCULATION: Emission and economic evaluation of pure hydrogen compare to natural gas2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The member states of European Union aim to promote the reduction of harmful emissions. Emissions from combustion processes cause effects on human health and pose environmental issues, for example by increasing greenhouse effect. There are two ways to reduce emissions; one is to promote renewable energy sources and the other to utilize more effectively the available fossil fuels until a long-term solution is available. Hence, it is necessary to strive for CO2 mitigation technologies applied to fossil fuels. Low natural gas prices together with high energy efficiency have made gas turbines popular in the energy market. But, gas turbine fired with natural gas come along with emissions of CO2, NOx and CO. However, these disadvantages can be eliminated by using gas turbine with precombustion CO2 capture, separating carbon from the fuel by using fuel reforming process and feeding pure hydrogen as a fuel. Hydrogen fired gas turbines are used in two applications such as a gas turbine with pre-combustion CO2 capture and for renewable power plants where hydrogen is stored in case as a backup plan. Although the CO2 emissions are reduced in a hydrogen fired gas turbine with a pre-combustion CO2 capture, there are still several challenges such as high flame temperatures resulting in production of thermal NOx. This project suggests a method for application of hydrogen fired gas turbine, using exhaust gas recirculation to reduce flame temperature and thus reducing thermal NOx. A NOx emission model for a hydrogen-fired gas turbine was built from literature data and used to select the best operating conditions for the plant. In addition, the economic benefits of switching from natural gas to pure hydrogen are reported. For the techno-economic analysis, investment costs and operating costs were taken from the literature, and an economic model was developed. To provide sensitivity analysis for the techno-economic calculation, three cases were studied. Literature review was carried out on several journal articles and websites to gain understanding on hydrogen and natural gas fired gas turbines. Results showed that, in the current state, pure hydrogen has high delivery cost both in the US and Europe. While it’s easy to access natural gas at low cost, therefore in the current state gas turbine fired with natural gas are more profitable than hydrogen fired gas turbine. But, if targeted hydrogen prices are reached while fuel reforming process technology are developed in the coming future the hydrogen fired gas turbine will compete seriously with natural gas.

  • 205.
    Goldberg, C.
    et al.
    Cranfield University, Bedfordshire, United Kingdom.
    Nalianda, D.
    Cranfield University, Bedfordshire, United Kingdom.
    Sethi, V.
    Cranfield University, Bedfordshire, United Kingdom.
    Pilidis, P.
    Cranfield University, Bedfordshire, United Kingdom.
    Singh, R.
    Cranfield University, Bedfordshire, United Kingdom.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Assessment of an energy-efficient aircraft concept from a techno-economic perspective2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 221, s. 229-238Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An increase in environmental awareness in both the aviation industry and the wider global setting has led to large bodies of research dedicated to developing more sustainable technology with a lower environmental impact and lower energy usage. The goal of reducing environmental impact has necessitated research into revolutionary new technologies that have the potential to be significantly more energy efficient than their predecessors. However, for innovative technologies in any industry, there is a risk that adoption will be prohibitively expensive for commercial application. It is therefore important to model the economic factors of the new technology or policy at an early stage of development. This research demonstrates the application of a Techno-economic Environmental Risk Assessment framework that may be used to identify the economic impact of an energy-efficient aircraft concept and the impact that environmental policy would have on the viability of the concept. The framework has been applied to a case study aircraft designed to achieve an energy saving of 60% in comparison to a baseline 2005 entry-into-service aircraft. The model compares the green aircraft concept to a baseline conventional aircraft using a sensitivity analysis of the aircraft direct operating cost to changes in acquisition and maintenance cost. The research illustrates an economically viable region for the technology. Cost margins are identified where the increase in operating cost due to expensive novel technology is counterbalanced by the reduction in cost resulting from low energy consumption. Viability was found to be closely linked to fuel price, with a low fuel price limiting the viability of energy-efficient aviation technology. In contrast, a change in environmental taxation policy was found to be beneficial, with the introduction of carbon taxation incentivising the use of an environmentally optimised aircraft.

  • 206.
    Guezgouz, M.
    et al.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Jurasz, Jakob
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Faculty of Management, Department of Engineering Management, AGH University.,Cracow, Poland.
    Bekkouche, B.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Ma, T.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Javed, M. S.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Kies, A.
    Frankfurt Institute for Advanced Studies, Goethe University Frankfurt, Frankfurt am Main, Germany.
    Optimal hybrid pumped hydro-battery storage scheme for off-grid renewable energy systems2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 199, artikel-id 112046Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of energy storage systems paves the way towards a high integration of renewable energy sources in the electricity generation sector. Considering above, this paper introduces a new energy management strategy to efficiently coordinate a hybrid energy storage system based on pumped hydro storage (long term bulk storage) with batteries (short term, more flexible). For the purpose of this analysis, hourly time series of irradiation, wind speed, temperature and real measured load (characteristic for farmstead) covering one year were gathered for the selected site in Algeria. The optimal size of the system is determined based on a multi-objective optimization using a grey wolf optimizer implemented in MATLAB software. The results indicate that the hybrid storage system enables achieving higher reliability at lower cost in comparison to a system with single storage technology. The use of hybrid storage also reduces the curtailment of renewable generation. Further findings reveal that the cost of an optimal energy supply system with 97.5% reliability is 0.162 €/kWh, 0.207 €/kWh and 1.462 €/kWh for hybrid storage, battery and pumped storage, respectively. However, sensitivity analysis shows that the optimal hybrid storage configuration is less resilient when changes in irradiation/temperature/load are considered. This indicates that special actions (upscale of installed power) must be undertaken to avoid lower performance of hybrid storage systems. In summary, the hybrid storage system seems to be better sized for consideration in optimized solar/wind conditions, but by avoiding oversizing they are less resilient to future potential changes in renewable energy availability.

  • 207.
    Guezgouz, M.
    et al.
    Mostaganem University, Algeria.
    Jurasz, Jakub
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. AGH University of Science and Technology, Cracow, Poland.
    Bekkouche, B.
    Mostaganem University, Algeria.
    Techno-economic and environmental analysis of a hybrid PV-WT-PSH/BB standalone system supplying various loads2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 3, artikel-id 514Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Algerian power system is currently dominated by conventional (gas- and oil-fueled) power stations. A small portion of the electrical demand is covered by renewable energy sources. This work is intended to analyze two configurations of renewables-based hybrid (solar–wind) power stations. One configuration was equipped with batteries and the second with pumped-storage hydroelectricity as two means of overcoming: the stochastic nature of the two renewable generators and resulting mismatch between demand and supply. To perform this analysis, real hourly load data for eight different electricity consumers were obtained for the area of Mostaganem. The configuration of hybrid power stations was determined for a bi-objective optimization problem (minimization of electricity cost and maximization of reliability) based on a multi-objective grey-wolf optimizer. The results of this analysis indicate that, in the case of Algeria, renewables-based power generation is still more expensive than electricity produced from the national grid. However, using renewables reduces the overall CO 2 emissions up to 9.3 times compared to the current emissions from the Algerian power system. Further analysis shows that the system performance may benefit from load aggregation. 

  • 208.
    Guo, K.
    et al.
    University of Stavanger, Stavanger, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    In-situ heavy and extra-heavy oil recovery: A review2016Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 185, s. 886-902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to the growing global energy demand and increasingly limited availability of conventional or easy-to-produce crude oils, extensive attention is being paid to the exploitation of unconventional heavy and extra-heavy oils. However, their inherent properties, characterized by high viscosity and poor mobility, coupled with the complex reservoir configuration, make the desired recovery processes very challenging. Although several in-situ recovery techniques have been employed in oil reservoirs worldwide, most of them are still suffering from low sweep and displacement efficiencies, high capital investment, potential formation damage and negative environmental footprints. This paper aims to provide a comprehensive review of the existing in-situ heavy oil recovery techniques, which fall into three categories of thermal injection, chemical injection and gas injection. Different aspects including the fundamental principles, main features, applicability, and limitations of these recovery processes are elaborated sequentially to illustrate the current technology status. Underlying mechanisms causing the relatively low recovery factors will also be pinpointed. Furthermore, this paper focuses on the technology using novel and active catalysts for simultaneous heavy oil upgrading and recovery, especially in the case of metallic nanocatalysts. Rationales, advantages and challenges regarding this in-situ catalytic upgrading technology will be extensively described for their potential implementation in fields. It is noteworthy that many recovery techniques are still limited to the laboratory scale with needs for further investigations. Therefore, this paper also covers the evaluation standards and analytical methodologies of heavy and extra-heavy oil recovery to establish experimental screening criteria. In the end, economic and environmental aspects of the in-situ catalytic upgrading technology have been briefly discussed. The objective of this review is to present a wide range of expertise related to the in-situ heavy oil recovery processes, and to introduce the in-situ catalytic upgrading technology as an effective and environmental friendly heavy oil recovery process.

  • 209.
    Guo, K.
    et al.
    Univ Stavanger, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Zhixin
    Univ Stavanger, Norway.
    Size-Dependent Catalytic Activity of Monodispersed Nickel Nanoparticles for the Hydrolytic Dehydrogenation of Ammonia Borane2018Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 1, s. 517-525Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nickel (Ni) nanoparticles (NPs) with controlled sizes in the range of 4.9-27.4 nm are synthesized by tuning the ratio of the nickel acetylacetonate precursor and trioctylphosphine in the presence of oleylamine. X-ray diffraction and transmission electron microscopy confirm the formation of the metallic Ni crystal phase and their monodispersed nature. These Ni NPs are found to be effective catalysts for the hydrolytic dehydrogenation of ammonia borane, and their catalytic activities are size-dependent. A volcano-type activity trend is observed with 8.9 nm Ni NPs presenting the best catalytic performance. The activation energy and turnover frequency (TOF) of the 8.9 nm NP catalyst are further calculated to be 66.6 kJ·mol-1 and 154.2 molH2·molNi -1·h-1, respectively. Characterization of the spent catalysts indicates that smaller-sized NPs face severe agglomeration, resulting in poor stability and activity. Three carbon support materials are thus used to disperse and stabilize the Ni NPs. It shows that 8.9 nm Ni NPs supported on Ketjenblack (KB) exhibit higher activity than that supported on carbon nanotubes and graphene nanoplatelets. The agglomeration-induced activity loss is further illustrated by immobilizing 4.9 nm Ni NPs onto KB, which exhibits significantly enhanced activity with a high TOF of 447.9 molH2·molNi -1·h-1 as well as an excellent reusability in the consecutive dehydrogenation of ammonia borane. The high catalytic performance can be attributed to the intrinsic activity of nanoparticulate Ni and the improved activity and stability due to the strong Ni/KB metal-support interactions.

  • 210.
    Guo, Kun
    et al.
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway.;Univ Stavanger, Natl IOR Ctr Norway, N-4036 Stavanger, Norway..
    Hansen, Vidar Folke
    Univ Stavanger, Dept Mech & Struct Engn & Mat Sci, N-4036 Stavanger, Norway..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Malardalen Univ, Dept Energy Bldg & Environm, S-72123 Vasteras, Sweden..
    Yu, Zhixin
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway.;Univ Stavanger, Natl IOR Ctr Norway, N-4036 Stavanger, Norway..
    Monodispersed nickel and cobalt nanoparticles in desulfurization of thiophene for in-situ upgrading of heavy crude oil2018Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 211, s. 697-703Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Monodispersed nickel (Ni) and cobalt (Co) nanoparticles (NPs) with different sizes are synthesized via the thermal decomposition of organometallic precursors by controlling the reaction temperature and surfactant amount. X-ray diffraction analysis of the as-prepared NP samples shows the formation of cubic Ni metal phases with good crystallinity, while the cubic Co metal samples are semi-amorphous. Transmission electron microscopy characterization further confirms that two Ni NP samples with average sizes of 9 and 27 nm, and Co NPs with an average size of 6 nm are successfully prepared with a narrow size distribution. Furthermore, catalytic performance of these monodispersed NPs towards the hydrodesulfurization (HDS) reaction, which plays a pivotal role in the upgrading of heavy crude oil, is evaluated under reservoir-relevant conditions using thiophene as a sulfur-containing model compound. Different parameters including particle size, catalyst dosage, hydrogen donor ratio, temperature, and reaction duration are systematically studied to optimize the catalytic HDS performance. The morphology and size of the spent NP catalysts after the reaction are also analyzed. The results show that the 9 nm Ni NPs exhibit the best HDS activity and stability compared with other catalysts, which suggests that such well-dispersed Ni NPs are promising candidates for the in-situ upgrading and recovery of heavy crude oil from underground reservoirs.

  • 211.
    Guo, Kun
    et al.
    Univ Stavanger, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Zhixin
    Univ Stavanger, Norway.
    Metallic nanoparticles for enhanced heavy oil recovery: promises and challenges2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, s. 2068-2073Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the increasing global energy demand, great attention has been focused on utilizing heavy oil and bitumen, which are potentially located ultra-deep underground and cannot be easily recovered. Numerous recovery approaches have been proposed for successful extraction of heavy hydrocarbons from ultra-deep reservoirs. However, these approached are often accompanied by high energy consumption, large amounts of wastewater generation, and undesirable environmental damage. Nanotechnology has appeared as one of the promising technologies for in-situ heavy oil recovery, e.g., employing metal-based nanoparticles. In this article, we provide a brief overview of metallic nanoparticles for in-situ enhanced recovery of heavy oil. It gives a general introduction of the potential advantages of nanoparticle catalysts for heavy oil recovery and illustrates the improved recovery mechanism. Some technology challenges related to this promising technology will also be pinpointed. These technology challenges need to be solved through further research and development before field applications. 

  • 212.
    Guo, S.
    et al.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Liu, Q.
    Chinese Academy of Sciences, Beijing, China.
    Zhao, J.
    Tianjin University, Tianjin, China.
    Jin, G.
    Inner Mongolia University of Science and Technology, Baotou, 014010, China.
    Wu, W.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jin, H.
    Chinese Academy of Sciences, Beijing, China.
    Mobilized thermal energy storage: Materials, containers and economic evaluation2018Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 177, s. 315-329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transportation of thermal energy is essential for users who are located far away from heat sources. The networks connecting them achieve the goal in efficient heat delivery and reasonable cost, especially for the users with large heat demands. However, it is difficult to satisfy the heat supply of the detached or emergent users with the existing pipelines. Therefore, a promising alternative, called mobilized thermal energy storage (M-TES), was proposed to deliver the heat flexibly without the restriction of networks. In this paper, a review of studies on M-TES is conducted in terms of materials, containers and economic evaluation. The potential candidates of materials, such as sugar alcohols, hydrated salts, alkalies and zeolite are reviewed and compared based on their thermophysical properties, price, advantages and disadvantages. Various containers, including the shell-and-tube, encapsulated, direct-contact, detachable and sorptive types, are discussed from the aspects of configuration, performance and utilization. Furthermore, the studies on the economic evaluation of M-TES systems are summarized and discussed based on the analysis of the economic indicators, including initial cost, operating cost, revenue, subsidy and energy cost. Finally, the challenges and future perspectives for developing M-TES are presented. © 2018 Elsevier Ltd

  • 213.
    Guo, S.
    et al.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Zhao, J.
    Tianjin University, Tianjin, China.
    Wang, W.
    Sun Yat-Sen University, Guangzhou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Jin, G.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Zhang, Z.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Gu, J.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Niu, Y.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Numerical study of the improvement of an indirect contact mobilized thermal energy storage container2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 161, s. 476-486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the melting and solidification behaviours of the PCM in an indirect contact mobilized thermal energy storage (ICM-TES) container were numerically investigated to facilitate the further understanding of the phase change mechanism in the container. A 2D model was built based on the simplification and assumptions of experiments, which were validated by comparing the results of computations and measurements. Then, three options, i.e., a high thermal conductivity material (expanded graphite) addition, the tube diameter and the adjustment of the internal structure of the container and fin installation, were analyzed to seek effective approaches for the improvement of the ICM-TES performance. The results show that the optimal parameters of the three options are 10vol.% (expanded graphite proportion), 22mm (tube diameter) and 0.468m2 (fin area). When the three options are applied simultaneously, the charging time is reduced by approximately 74% and the discharging time by 67%.

  • 214.
    Guo, S.
    et al.
    MOE, Tianjin University, Tianjin, China.
    Zhao, J.
    MOE, Tianjin University, Tianjin, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Jin, G.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Wang, X.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Economic assessment of mobilized thermal energy storage for distributed users: A case study in China2016Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 88, s. 656-661Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mobilized thermal energy storage (M-TES) system can be an alternative of the conventional heating system to meet the heat demand for distributed users. This paper conducted a case study of the M-TES system in China. The operating strategies (OS) of the M-TES with different transportation schemes were compared. Moreover, the economic assessment was performed based on the project's net present value (NPV) and payback period (PBP). The OS with 6 trips per day is the most profitable with pay-back time of about 2, 3 and 5 years if the waste heat costs at the level of 0 €/MWh, 3300€/MWh, and 6600 €/MWh, respectively. 

  • 215.
    Guo, Shaopeng
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhao, J.
    Tianjin University, China .
    Li, Xun
    Tianjin University, China .
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Numerical simulation study on optimizing charging process of the direct contact mobilized thermal energy storage2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, s. 1416-1423Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Mobilized thermal energy storage (M-TES) system is considered as an attractive alternative to supply heat to distributed heat users, especially when the waste heat from industries is used as a heat source. From our previous study it was known that the charging time of M-TES system was more than four times of the discharging time, which was a critical issue for the application of M-TES. To improve the charging performance of the system and further understand the mechanism of melting process, a 2-dimensional (2D) numerical simulation model was developed in ANSYS FLUENT. The model was validated by the experimental measurements. The results showed that the model could be used for the engineering analysis. With the validated model, different options to shorten the charging time were investigated including increasing flow rate of thermal oil, creating channels before charging and adding wall heating. Correspondingly, around 25%, 26% and 29% of the charging time could be reduced respectively compared to the experiment with a thermal oil flow rate of 9.8 L/min, according to the numerical simulation. In addition, if the last two options could be applied simultaneously, more than half of the melting time might be shortened without changing the flow rate of thermal oil. 

  • 216.
    Guo, Shaopeng
    et al.
    Inner Mongolia Univ Sci & Technol, China.
    Zhao, Jun
    Tianjin Univ, China..
    Wang, Weilong
    Sun Yat Sen Univ, China..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jin, Guang
    Inner Mongolia Univ Sci & Technol, China..
    Wang, Xiaotong
    Inner Mongolia Univ Sci & Technol, China..
    Techno-economic assessment of mobilized thermal energy storage for distributed users: A case study in China2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, s. 481-486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mobilized thermal energy storage (M-TES) system is a promising alternative to conventional heating systems to meet the heat demand for distributed users. This paper provided a techno-economic assessment of the M-TES system based on a case study in China. According to the analysis of the design specifications of the heating system, the suitability of matching the M-TES with existing heating systems was analyzed. The results show that the M-TES is appropriate for use with heating systems with a fan-coil unit and under-floor pipe. Containers and operating strategies for the M-TES with different transportation schemes were also designed. The maximum allowed load of the M-TES container is 39 t according to the discussion of transportation regulations on the road. The cost and income of the M-TES in the study case were estimated, and the net present value (NPV) and payback period (PBP) were also calculated. The best operating strategy is the use of 2 containers and 4 cycles of container transportation per day, with a PBP of approximately 10 years. The M-TES is applicable for middle and small-scale heat users in China. (C) 2016 Elsevier Ltd. All rights reserved.

  • 217.
    Gustafsson, M.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Swing Gustafsson, Moa
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Myhren, J. A.
    Dalarna University, Falun, Sweden.
    Bales, C.
    Dalarna University, Falun, Sweden.
    Holmberg, S.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, s. 108-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact. 

  • 218.
    Gustavsson, L. K.
    et al.
    Karlskoga Environment and Energy Company.
    Heger, S.
    Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Aachen 52062, Germany .
    Ejlertsson, J.
    Scandinavian Biogas Fuels AB, Holländaregatan 21A, Stockholm 11160, Sweden.
    Ribé, Veronica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hollert, H.
    Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Aachen 52062, Germany .
    Keiter, S. H.
    Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Aachen 52062, Germany .
    Industrial sludge containing pharmaceutical residues and explosives alters inherent toxic properties when co-digested with oat and post-treated in reed beds2014Ingår i: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 26, nr 1, s. Article number 8-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Methane production as biofuels is a fast and strong growing technique for renewable energy. Substrates like waste (e.g. food, sludge fromwaste water treatment plants (WWTP), industrial wastes) can be used as a suitable resource for methane gas production, but in some cases, with elevated toxicity in the digestion residue. Former investigations have shown that co-digesting of contaminated waste such as sludge together with other substrates can produce a less toxic residue. In addition, wetlands and reed beds demonstrated good results in dewatering and detoxifying of sludge. The aim of the present study was to investigate if the toxicity may alter in industrial sludge co-digested with oat and post-treatment in reed beds. In this study, digestion of sludge from Bjorkborn industrial area in Karlskoga (reactor D6) and co-digestion of the same sludge mixed with oat (reactor D5) and post-treatment in reed beds were investigated in parallel. Methane production as well as changes in cytotoxicity (Microtox(R); ISO 11348-3), genotoxicity (Umu-C assay; ISO/13829) and AhR-mediated toxicity (7-ethoxyresorufin-O-deethylase (EROD) assay using RTW cells) were measured. Results: The result showed good methane production of industrial sludge (D6) although the digested residue was more toxic than the ingoing material measured using microtox30min and Umu-C. Co-digestion of toxic industrial sludge and oat (D5) showed higher methane production and significantly less toxic sludge residue than reactor D6. Furthermore, dewatering and treatment in reed beds showed low and non-detectable toxicity in reed bed material and outgoing water as well as reduced nutrients. Conclusions: Co-digestion of sludge and oat followed by dewatering and treatment of sludge residue in reed beds can be a sustainable waste management and energy production. We recommend that future studies should involve co-digestion of decontaminated waste mixed with different non-toxic material to find a substrate mixture that produce the highest biogas yield and lowest toxicity within the sludge residue.

  • 219.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Citizen proposals at local level: Inclusive or exclusive participatory democracy?2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Participatory democracy emphasizes the importance of the public´s political participation. Citizen participation initiatives in Sweden include among others civic dialogues in the planning, citizen proposals and e-petitions.  While participatory democrats recognize the need for representative democracy they also see the possibility and benefits of more political involvement by the public than is currently practiced.The arguments in favor of enhancing citizen participation focus on its different benefits. Based on participatory democracy, deliberative democracy and social capital   Michel (2011) highlights four contributions of participation to elements of democracy: influence on decision-making, inclusion, skills and virtues, deliberation, and legitimacy. In this paper the design and practice of citizen involvement through citizen proposals in the municipality of Eskilstuna is studied.  The amount submitted proposals in Eskilstuna is growing. Still, this initiative for increased public participation in form of citizen proposals in Eskilstuna have some shortcomings regarding inclusiveness, deliberation and development civic skills.

  • 220.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Corporate Greening: Product and Production Perspectives2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis describes corporate greening in general, and specifically the environmental technology (ET) sector as a green sector. The thesis has also particular focus on production and products related aspects and the influence of the environmental profile of the ET sector on the environmental engagement of companies in the sector. The study is based on a questionnaire-based survey, online surveys and on semi-structured open-ended interviews. The organizations within the ET sector were identified using existing platforms within this sector: Sustainability Sweden and Swentec. The results show that not all companies and industry associations in the ET sector clearly distinguish between product and production related environmental aspects. Furthermore, the product related environmental profile, which constitutes the legitimacy for the sector, can influence companies’ environmental strategy, not only positively but also negatively. The results from the survey on Global Supersector Leaders 2009/2010 in Dow Jones Sustainability Indexes (DJSI) show that all companies are aware of production and product related environmental issues. Based on results from this survey a model of corporate environmental profile consisting of product and production oriented activities as well as initiatives that go beyond the core business operations is proposed. These initiatives can be divided into two groups: environmental education and environmental projects and sponsorship. This thesis proposes products and production related impacts and environmental activities as bases for defining corporate environmental profiles, corporate greening, and for defining ‘green’ and ‘green-green’ business as well as environmental leaders. The distinction between product and production related environmental initiatives as well as the other dimensions of the proposed model in this thesis can support companies in their communication of environmental performance and environmental activities.  Furthermore, ‘competitive advantage’, ‘environmental responsibility’ and ‘environmental leadership’ should motivate companies within the ET sector to be ‘vocal’ green-green firms.

  • 221.
    Guziana, Bozena
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dobers, Peter
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    How Sustainability Leaders Communicate Corporate Activities of Sustainable Development.2013Ingår i: Corporate Social Responsibility and Environmental Management, ISSN 1535-3958, E-ISSN 1535-3966, Vol. 20, nr 4, s. 193-204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the corporate quest for sustainable development, production- and product-related environmental impacts of a company can form a basis for de fining the corporate environmental profile, as well as for de fining environmental leaders. Awareness of the production- and productrelated dimensions of the environmental profile varied among companies. This paper studied descriptions and reporting of environmental issues among 19 companies ranked as Global Supersector Leaders in 2009/2010 by the Dow Jones Sustainability Index (DJSI). The results show that all of these companies are aware of production- and product-related environmental aspects. There are also examples, both as headings on websites and as sections in sustainability reports, where companies structure their environmental initiatives separately with respect to production (or their own operations) and the product. The paper ends with a proposed modelof corporate environmental profile.

  • 222.
    Guziana, Bozena
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Song, Han
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Policy Based Scenarios for Waste-to-Energy Use: Swedish Perspective2014Ingår i: Waste and Biomass Valorization, ISSN 1877-2641, Vol. 5, nr 4, s. 679-688Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of waste for energy purposes becomes increasingly interesting with respect to waste management and the energy systems. The decisions on alternative uses of waste for energy are mainly influenced by different policies, waste management, energy supply and use, as well as technologies. Two important issues, namely, a clear priority of waste prevention in waste management within EU and the growing concern for food losses and food waste at global and national level, shall be carefully considered and addressed. This paper proposes policy based scenarios for waste-to-energy systems with a focus on Sweden and with a broader EU approach. As baseline for the scenario development an inventory of waste-to-energy related policies and goals on international, national, regional and local level as well as inventory of existing scenarios and reports with future trends is made. The main substitute for fossil fuels and the possibilities for renewable energy export are basic elements that define scenarios. Biofuels and electricity are identified as main substitutes for the fossil fuels. A low waste availability level is recommended to be included in sensitivity analysis for scenarios. This paper assumes relative decoupling in Low Waste scenario in 2030, and absolute decoupling first in 2050.

  • 223.
    Haifang, Lyu
    et al.
    Academy of Chinese Energy Strategy, China University of Petroleum, Beijing, Ch.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Academy of Chinese Energy Strategy, China University of Petroleum, Beijing, Ch.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Bin, Xv
    Academy of Chinese Energy Strategy, China University of Petroleum, Beijing, Ch.
    Research on Chinese Solar Photovoltaic Development Based on Green-trading Mechanisms in Power System by Using a System Dynamics Model2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 3960-3965Artikel i tidskrift (Refereegranskat)
  • 224.
    Hakalehto, E.
    et al.
    Finnoflag Oy, Kuopio and Siilinjärvi, Finland.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A microbiological approach to the ecosystem services2018Ingår i: Microbiological Environmental Hygiene, Nova Science Publisher Inc. , 2018, s. 433-474Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Man has always exploited the environment for securing human life and culture. This “tradition” is both embedded into our instincts as well as a mode of behavior and a learnt method of survival in our societies. However, alongside with the globalization of the economy, internationalization, industrialization and population growth, the consequences of the one-sided approach of the past have become unbearable for the environment. Consequently, in order to maintain life on earth in its current form, we should establish new thinking and modes of action. Therefore, the survival strategies for Mankind should inherently contain the strive for sustainability, as well as the tendency to avoid past mistakes, and to repair them instantaneously whenever possible. The agricultural tradition of different nations leans on the centuries old wisdom of human civilization in a good sense. For example, the East Asian agricultural societies have learnt to handle each piece of land in their possession in an individual manner, taking into account the local environmental conditions. These principles are now more and more unanimously accepted, at least in theory. Also, the industrial ecosystem needs to be functioning in the natural way, and in balance with the environment. This is a necessity in the reversion or prevention of any developing environmental catastrophes that could wait behind the corner. As the major vehicles for the circulation of matter, microbes are in a key position and provide means for finding the solutions to serve the global ecosystems. In the aftermath of a vast environmental crisis, namely the oil leakage from the “Deepwater Horizon” oil platform well in the Mexican Gulf in the year 2010, it was noticed that the dramatic consequences of the spill were mitigated and the worst scenario of destruction avoided thanks to the cleaning actions of the marine micro-organisms. This was a positive result both ecologically and in economic sense. It further encouraged the scientists to find and isolate microbial strains which could be used for such operations. Although the natural microflora compensated and mitigated the effects of the Deepwater Horizon accident surprisingly well in 2010, there have been observations and concerns about the long term effects of this ecocatastroph (Geggel, 2015).

  • 225.
    Hakalehto, E.
    et al.
    University of Helsinki, Helsinki, Finland.
    Heitto, A.
    University of Helsinki, Helsinki, Finland.
    Andersson, Henny
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jansson, Joakim
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Reijonen, T.
    Savonia University of Applied Sciences, Kuopio, Finland.
    Suhonen, A.
    Savonia University of Applied Sciences, Kuopio, Finland.
    Jääskeläinen, A.
    Savonia University of Applied Sciences, Kuopio, Finland.
    Laatikainen, R.
    University of Eastern Finland, Kuopio, Finland.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Some remarks on processing of slaughterhouse wastes from ecological chicken abattoir and farm2016Ingår i: Microbiological Industrial Hygiene, Nova Science Publishers, Inc. , 2016, s. 271-293Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    In the meat industries, it is always of high importance to follow up the zoonotic and other hazardous micro-organisms, and to prevent their risky distribution, emission and dissemination. Besides proper hygiene control, as well as organized exploitation of the side streams and slaughterhouse wastes helps in the hygienization of the biomasses, processes, and the entire industry. During this experimentation it turned out that it was possible to produce gases and chemical goods, not only from the carboxylates, but also from the more tedious protein and lipid containing wastes. Moreover, these promising results were obtained from a substrate mix with manure and wood chips. These results implied to the high versatility and flexibility of the bioprocess during Pilot A tests within the European Union Baltic Sea region project ABOWE. In Sweden these tests were carried out using the combined wastes from the ecological chicken farm and abattoir as the raw materials. This is a report of the practical set up during intensive experimentation conducted jointly by the Swedish and Finnish personnel. The report of the runs in Sweden is presented also in the public report of the European Union funded project (www.abowe.eu).

  • 226.
    Hallin, Anette
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hoppe, Magnus
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Mörndal, Marie
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Styrning och samverkan för hållbar stadsutveckling - förstudierapport2014Rapport (Övrigt vetenskapligt)
  • 227.
    Hallin, Anette
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Hoppe, Magnus
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mörndal, Marie
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Åberg, Michelle
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Mind the gap: understanding organisational collaboration2017Konferensbidrag (Refereegranskat)
  • 228.
    Hallstrom, Olof
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Fueldner, Gerrit
    Fraunhofer Inst Solare Energiesyst ISE, Freiburg, Germany.
    Integration of sorption modules in Sydney type vacuum tube collector with air as heat transfer fluid2015Ingår i: INTERNATIONAL CONFERENCE ON SOLAR HEATING AND COOLING FOR BUILDINGS AND INDUSTRY, SHC 2014, 2015, Vol. 70, s. 445-453Konferensbidrag (Refereegranskat)
    Abstract [en]

    Reduced thermal losses and simplified system integration have previously been identified as main opportunities to improve the concept of collector integrated sorption modules for solar heating and cooling. A concept for a facade integrated sorption collector using Sydney type vacuum tube technology and air based heat transfer has been developed and tested in the laboratory. The results from the tests have been used to validate an existing TRNSYS model that has been modified for use with air as heat transfer fluid. The work has been conducted within the FP7 EU iNSPiRe project with the aim to develop a plug & play solar cooling and heating solution. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 229.
    Hallström, Olof
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Design Optimization of a Sorption Integrated Sydney Type Vacuum Tube Collector2017Ingår i: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 139, nr 2, artikel-id 021007Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to reach the targets on emissions set by the European Commission, both new and existing buildings must reduce their fossil fuel inputs. Solar thermal cooling supplying on-site renewable heating and cooling could potentially contribute toward this goal. In this paper, a novel concept for solar thermal cooling providing efficient coproduction of cooling and heating based on sorption integrated vacuum tube collectors is proposed. A prototype collector has been constructed and tested in a solar laboratory based on a method developed specifically for sorption integrated collectors. From the test results, the key performance parameters have been determined and used to calibrate a mathematical model for trnsys environment. System simulation has been conducted to optimize the collector and sorption module configuration by performing a parametric study where different vacuum tube center-center (C-C) distances and sorption module designs are tested for a generic hotel in Ankara, Turkey. The parametric study showed that the heating and cooling output per year can be as high as 1000 kWh/m2 for solar fractions above 50%, and that the output per sorption module compared to the prototype can more than double with an optimized design. Furthermore, cooling conversion efficiencies defined as total cooling output per total solar insolation can be as high as 26% while simultaneously converting 35-40% of the incident solar energy into useful hot water.

  • 230.
    Hallström, Olof
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Füldner, G.
    Fraunhofer-Institut für Solare Energiesysteme ISE, Germany.
    Spahn, H. -J
    Vaillant GmbH, Germany.
    Schnabel, L.
    Fraunhofer-Institut für Solare Energiesysteme ISE, Germany.
    Salg, F.
    Vaillant GmbH, Germany.
    Development of collector integrated sorption modules for solar heating and cooling: Performance simulation2014Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 48, s. 67-76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar thermal cooling has difficulty to emerge as an economically competitive solution for small systems mainly due to high investment cost and system complexity [1]. Therefore developments of principally new system solutions are needed. This paper describes such a solution with sorption modules directly integrated into a solar thermal collector. The focus of the work has been to find key parameters influencing the module and the system efficiency. A validated model of a sorption collector has been implemented into a simplified system deck providing cooling, heating and domestic hot water to static loads in the system modelling environment TRNSYS [2]. Simulations have been conducted for different boundary conditions and at two locations with different climatic conditions. Thermal losses from the collector as well as internal thermal losses inside the collector were found to be the most important parameters influencing efficiency. The system simulations gave overall thermal cooling efficiencies in the range of 0.12-0.27 and electrical cooling efficiencies in the range of 15-45 depending on collector technology, climate and control strategy.

  • 231.
    Han, Song
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Techno-economic analysis of an integrated biorefinery system for poly-generation of power, heat, pellets and bioethanol2014Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 38, nr 5, s. 551-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioethanol is an alternative to fossil fuels in the transportation sector. The use of pellet for heating is also an efficient way to mitigate greenhouse gas emissions. This paper evaluates the techno-economic performance of a biorefinery system in which an existing combined heat and power (CHP) plant is integrated with the production of bioethanol and pellet using straw as feedstock. A two-stage acid hydrolysis process is used for bioethanol production, and two different drying technologies are applied to dry hydrolysis solid residues. A sensitivity analysis is performed on critical parameters such as the bioethanol selling price and feedstock price. The bioethanol production cost is also calculated for two cases with either 10 year or 15 year payback times. The results show that the second case is currently a more feasible economic configuration and reduces production costs by 36.4%-77.3% compared to other types of poly-generation plants that are not integrated into existing CHP plants. 

  • 232.
    Hansen, Rickard
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Analysis of methodologies for calculating the heat release rates of mining vehicle fires in underground mines2015Ingår i: Fire Safety Journal, ISSN 0379-7112, Vol. 71, s. 194-216Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Four different methodologies for calculating the ignition of different components on a mining vehicle in a mine drift were analysed. The results were compared with two full-scale fire experiments on mining vehicles. The four different methods are based on physical relations for fire spread between combustible components of the mining vehicles. The first two methods use a critical heat flux as ignition criterion while the other two methods use an ignition temperature. A sensitivity analysis was performed and the most influencing parameter of the methods was further analyzed. The calculated results were compared with the measured results from the experiments. The two methodologies applying an ignition temperature criterion were ruled out at as the surface temperatures of all fuel components never achieved the corresponding ignition temperatures. For the two methods applying a critical heat flux criterion it was found that the expression not including a flame radiation term was not suitable as it was found that the flame radiation played an important part with respect to spread mechanisms. The expression containing a flame radiation term was found to come very close to the observed ignition times, except in the case of the left, rear tyre of the drilling rig where it predicted a much higher ignition time than the one observed. The difference is unclear and would have to be investigated further. It was also found that the surface heat losses had none effect on the output results and could therefore be neglected in the calculations. In the case of the wheel loader the calculated heat release rate curves did not match the measured curve as well as in the case of the drilling rig. The difficulty in this case consists of accurately predicting the mechanical failure of a component - in this case a suction hose - that would initiate the very significant hydraulic oil pool fire.

  • 233.
    Hansen, Rickard
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Statistical expressions on water based wildfire suppression in Sweden, 1996-20112015Ingår i: International Journal of Safety and Security Engineering, ISSN 2041-9031, E-ISSN 2041-904X, Vol. 5, nr 2, s. 124-141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Little research has been conducted with respect to water requirements for wildfire suppression. An exploratory and robust regression analysis was conducted on statistical material extracted from a Swedish database, focusing on data related to the fire suppression. The variables included are the amount of water applied, application rate of water, extinguishing time, flame height, and the total fire area. The results of the analysis with potential relationships are described, discussed, and compared with results from earlier research. After initial outlier detection, a robust regression analysis was performed and relationships developed. It was found that the developed relationships could predict the dependent variable very well; this was especially the case with the extinguishing time as a function of the total fire area. The relationship with the lowest ability to predict the dependent variable was the application rate of water as a function of the total fire area. The large number of parameters and their included uncertainties could be an explanation to the increased inability to predict the dependent variable. When comparing the control times of earlier conducted building fire studies with the extinguishing times of developed relationships, it was found that the control times were much longer than the corresponding extinguishing times. The reason behind was most likely due to the difference in the fire area applied in the equations. The resulting relationships for the grass fuel type were found to have lower ability to predict the dependent variable. The reason behind this is unclear and needs to be investigated further.

  • 234.
    Hansen, Rickard
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Study of heat release rates of mining vehicles in underground hard rock mines2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    A unique study on fire safety in hard rock underground mines with focus on heat release rates of mining vehicles is presented. A literature inventory was conducted with respect to fires in underground hard rock mines, which revealed that the most common fire cause in underground mines was flammable liquid sprayed onto hot surface and the most common fire object was a vehicle. A major concern was the lack of documented fire experiments in mining vehicles and heat release rate curves. It also revealed the limited research carried out on fire safety and fire development on vehicles found in hard rock underground mines.

    In order to fill the gap of knowledge lack on heat release rates, fire experiments were carried out on wood cribs and wooden pallets in a model-scale tunnel with longitudinal ventilation where the distance between the fuel items were kept constant as well as varied. Different ignition criteria were applied in the ensuing calculations. It was found that the critical heat flux criterion generally showed very good agreement with the corresponding results of performed fire experiments but tended to have too short ignition times when the distance between the fuel items was increased. The ignition temperature criterion generally performed poorly compared with the measured results, but it was found that the accuracy improved considerably as the distance between the fuel items and the amount of energy accumulated on the fuel surface was increased.

    As a final approach, two full-scale fire experiments were carried out in an operative underground mine using a wheel loader and a drilling rig respectively. The resulting heat release rates of the experiments were compared with calculated overall heat release rates applying the different ignition criteria. It was found that the critical heat flux criterion resulted in ignition times very close to the observed ignition times. The ignition temperature criterion resulted in surface temperatures that never achieved the corresponding ignition temperatures. Some difficulties were experienced when calculating the heat release rate curve of the wheel loader, as it was difficult to accurately predict the mechanical failure of a significant part initiating the highly significant fire in the hydraulic oil. Additional heat terms were added to the heat balance, where the added flame radiation term was found to have a large impact on the output results while the heat loss terms were found to have very little effect.

  • 235.
    Hansen, Rickard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ingason, Haukur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Full-scale fire experiments with mining vehicles in an underground mine2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report comprises two full scale fire experiments in a mine drift in Sala, Sweden,involving a loader and a drilling rig respectively.

    It was found in the experiment involving the loader that the front part of the vehiclenever ignited. The maximum measured heat fluxes at the front tyres were found tonever exceed the critical heat flux of natural rubber and thus ignition never occurred.Furthermore, the maximum temperature recorded at the hydraulic hoses in the waistwas 381 K, thus the low temperatures did not allow for further fire spread. The maximumheat release rate from the experiment was 15.9 MW and it was attained approximately 11 minutes after ignition. The resulting heat release rate curve of the wheel loaderfire displays a fire that is dominated by initially the sudden increase when primarily the first tyre is engulfed by flames and then by the slowly declining heat release ratesof the large tyres of the vehicle. Still, the stop of fire spread from the waist and forward clearly shortened the duration of the fire considerably.

    It was found in the experiment with the drilling rig that the entire vehicle had participated in the fire and the combustible material had been consumed – except for the hydraulic hoses approximately two meters in front of the cab and forward, some amount of hydraulic oil and most of the low voltage cable on the cable reel. The maximum heatrelease rate from the experiment was 29.4 MW and it was attained after 21 minutes. The resulting heat release rate curve of the drilling rig displays a fire with high heat release rates and relatively short lived.

  • 236.
    Hansen, Rickard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ingason, Haukur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Heat release rate measurements of burning mining vehicles in an underground mine2013Ingår i: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 61, s. 12-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heat release rates from two full-scale fire experiments with mining vehicles in an underground mine are presented. The mining vehicles involved were a wheel loader and a drilling rig typical for mining operations. The calculated peak heat release rate of the loader was 15.9 MW and occurred after approximately 11 min from ignition. The calculated peak heat release rate of the drilling rig was 29.4 MW and occurred after approximately 21 min from ignition. The heat release rate was calculated from measured data of gas concentrations of oxygen, carbon monoxide and carbon dioxide, measured gas velocity and measured gas temperatures. The fuel load of the wheel loader consisted mainly of the tyres, the hydraulic oil and the diesel fuel. The fuel load of the drilling rig consisted mainly of the hydraulic oil and the hydraulic hoses. The calculated heat release rate curves were controlled by comparing the summed up energy contents of the participating components with the integrated heat release rate curves. © 2013 Elsevier Ltd.

  • 237.
    Hao, Y.
    et al.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Li, W.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Tian, Z.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, 100190, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Jin, H.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Integration of concentrating PVs in anaerobic digestion for biomethane production2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, ISSN 0306-2619, Vol. 231, s. 80-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biogas produced from anaerobic digestion processes is considered as an important alternative to natural gas and plays a key role in the emerging market for renewable energy. Aiming at achieving a more sustainable and efficient biomethane production, this work proposed a novel energy system, which integrates concentrating photovoltaic/thermal (C-PV/T) hybrid modules into a biogas plant with chemical absorption for biogas upgrading. The investigated energy system was optimized based on the data from an existing biogas plant, and its techno-economic feasibility was evaluated. Results show that about 7% of the heat consumption and 12% of the electricity consumption of the biogas plant can be covered by solar energy, by using the produced heat in a cascade way according to the operating temperature of different processes. The production of biomethane can also be improved by 25,800 N m3/yr (or 1.7%). The net present value of the integrated system is about 2.78 MSEK and the payback period is around 10 years. In order to further improve the economic performance, it is of great importance to lower the capital cost of the C-PV/T module. 

  • 238.
    Hellstrand, Stefan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The challenges of measuring sustainability performance2017Ingår i: Natural Resources Available Today and in the Future: How to Perform Change Management for Achieving a Sustainable World, Springer International Publishing , 2017, s. 57-71Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 239.
    Hellstrand, Stefan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation. Nolby Ekostrategi, Kil, Sweden.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Biologic resources2017Ingår i: Natural Resources Available Today and in the Future: How to Perform Change Management for Achieving a Sustainable World, Springer International Publishing , 2017, s. 93-156Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 240.
    Hennessy, Jay
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. RISE Research Institutes of Sweden AB.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Mälardalens högskola, Akademin för innovation, design och teknik.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Räftegård, Oskar
    RISE Research Institutes of Sweden.
    Economic feasibility of commercial heat-to-power technologies suitable for use in district heating networks2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 1721-1727, artikel-id EGYPRO33942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent improvements in heat-to-power (HtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. HtP is used extensively in power generation via the steam Rankine cycle, but so far has not been used in district heating (DH). The aim of the study is to analyze the economic feasibility of using HtP technologies in a DH network. This is achieved by establishing suitable technologies and calculating the levelized cost of electricity (LCOE) under conditions that may be found in DH. The result, for the vendors, temperatures and assumptions considered, is a range of 25–292 €/MWh, excluding the cost of heat. The breadth of this range in part reflects the importance of selecting appropriate products to match the heat source temperature.

  • 241.
    Hennessy, Jay
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. RISE Research Institutes of Sweden, Box 857, SE-501 15 Borås, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Flexibility in thermal grids: A review of short-term storage in district heating distribution networks2019Ingår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 2430-2434Konferensbidrag (Refereegranskat)
    Abstract [en]

    Future energy systems need to be more flexible. The use of cross-sector coupling in combination with thermal storage in thermal grids has been shown to provide such flexibility. The presented study reviews how short-term storage in district heating distribution networks is used or modelled for flexibility, what are the most important parameters, and where the knowledge gaps remain. The results show that the potential for flexibility from district heating has not been fully exploited. Sensible thermal storage tanks are 50-100 times cheaper than electrical storage and storage in the distribution network requires little additional investment in infrastructure. In some countries, the majority of district heating systems have sensible thermal storage tanks, with as much as 64 % of their capacity available for flexibility services. Initial results suggest that only smaller networks are prevented from using the distribution network for storage, but the impacts of this type of use on the physical components and the capacity limitations remain unclear and show a need for standardised methods for analysis. There is a growing interest, both in Europe and China, in the use of short-term storage in district heating to provide flexibility, particularly in the form of ancillary services to the electricity grid, but implementations of these techniques are rare. The presented study identifies a number of remaining knowledge gaps that should be addressed in order to harness available flexibility in district heating.

  • 242.
    Hennessy, Jay
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. RISE Research Institutes of Sweden, Borås, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Towards smart thermal grids: Techno-economic feasibility of commercial heat-to-power technologies for district heating2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, s. 766-776Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent improvements in low-temperature heat-to-power (LTHtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. LTHtP has so far not been used in district heating. The aim of the study is to establish under what conditions the use of existing LTHtP technology is technically and economically feasible using a district heating system as the heat source. The organic Rankine cycle (ORC) is identified as the most interesting LTHtP technology, due to its high relative efficiency and the commercial availability of devices operating at temperatures in the district heating operating range. The levelised cost of electricity of several ORC devices is calculated for temperatures found in district heating, assuming a zero cost of heat. A case study from Sweden is used to calculate the levelised cost of electricity, the net present value and payback period, based on income from the electricity produced, excluding taxes. Hourly spot market electricity prices from 2017 are used, as well as forecast scenarios for 2020, 2030 and 2040. A sensitivity study tests the importance of electricity price, cost of heat and capital/installation cost. Based on the case study, the best levelised cost of electricity achieved was 26.5 EUR/MWh, with a payback period greater than 30 years. Under current Swedish market conditions, the ORC does not appear to be economically feasible for use in district heating, but the net present value and payback period may be significantly more attractive under other countries’ market conditions or with reduced capital costs. For a positive net present value in the Swedish market the capital cost should be reduced to 1.7 EUR/W installed, or the average electricity price should be at least 35.2 EUR/MWh, if the cost of heat is zero. The cost of heat is an important factor in these calculations and should be developed further in future work.

  • 243.
    Hermansson, K.
    et al.
    Sigholm Konsult, Västerås, Sweden.
    Kos, C.
    Flowocean AB, Västerås, Sweden.
    Starfelt, F.
    Vattenfall AB, Uppsala, Sweden.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindberg, Carl-Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB Corporate Research, Västerås, Sweden.
    Zimmerman, Nathan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An Automated Approach to Building and Simulating Dynamic District Heating Networks2018Ingår i: IFAC-PapersOnLine, ISSN 2405-8963, Vol. 51, nr 2, s. 855-860Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Nordic countries, district heating accounts for a large share of the consumers’  heat demand. In Sweden, roughly 50% of the total heat demand is attributed to district heating. Which, over the past few years, is equivalent to around 50 TWh, and imposes a difficult balance between supply and demand for the suppliers of district heating. For large networks the propagation of heat from supplier to end-user can vary several hours. Further complexities of large networks, which can consist of multiple overlapping rings, is that during transient conditions the flow can actually change direction. A dynamic modeling library has been developed in Modelica using OpenModelica for district heating networks. Methods for modeling, handling data, simulating and the visualization of results has been developed using Matlab. The model has been validated using data from Mälarenergi  AB, a local provider of district heating in Västerås, Sweden. The model provides to an acceptable degree in predicting the heat propagation and temperature distribution in a localized case study. Adding a higher level of robustness, the model has the capacity to handle bi-directional and reversing flows in complex ring structures. Through this work, the combination of OpenModelica and Matlab, a framework for automating the building and simulation of district heating networks is obtainable. The implications of automating network modeling from computer-aided design drawings allows for a quick robust overview of how the network is working and how prospective additions to the network could impact the end-users. Furthermore, incorporating visual aspects for heat propagation in a network contributes to a higher understanding of complex network structures. 

  • 244.
    Hoggett, R.
    et al.
    University of Exeter, UK.
    Bolton, R.
    University of Edinburgh, UK.
    Candelise, C.
    Imperial College London, UK.
    Kern, F.
    University of Sussex, UK.
    Mitchell, C.
    University of Exeter, UK.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Supply chains and energy security in a low carbon transition2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 123, s. 292-295Artikel i tidskrift (Övrigt vetenskapligt)
  • 245.
    Hokkanen, S.
    et al.
    Lappeenranta University of Technology, Finland.
    Repo, E.
    Lappeenranta University of Technology, Finland.
    Johansson Westholm, Lena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lou, S.
    University of Minnesota, United States.
    Sainio, T.
    Lappeenranta University of Technology, Finland.
    Sillanpää, M.
    Lappeenranta University of Technology, Finland.
    Adsorption of Ni2+, Cd2+, PO4 3- and NO3 - from aqueous solutions by nanostructured microfibrillated cellulose modified with carbonated hydroxyapatite2014Ingår i: Chemical Engineering Journal, ISSN 1385-8947, Vol. 252, s. 64-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The adsorption of Ni2+, Cd2+, PO4 3- and NO3 - by carbonated hydroxyapatite (CHA) modified microfibrillated cellulose (MFC) was studied in the aqueous solution. The modified adsorbent was characterized using elemental analysis, FTIR, SEM and EDAX analysis. The adsorption studies were conducted in batch mode. The effects of pH, contact time, the concentration of metals and the regeneration efficiency were studied. The removal of Ni2+, Cd2+, PO4 3- and NO3 - was not pH dependent. The maximum removal capacities of the CHA/MFC adsorbent for Ni2+, Cd2+, PO4 3- and NO3 - were 2.021, 1.224, 0.843 and 0.209mmol/g, respectively. The Langmuir and Sips models were representative to simulate adsorption isotherms. The results of adsorption kinetic indicate that adsorption was very fast for all studied compounds.

  • 246.
    Honnanayakanahalli Ramakrishna, Prajwal
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    MODELING, SIMULATION AND OPTIMIZATION OF A SUBMERGED RENEWABLE STORAGE SYSTEM INTEGRATED TO A FLOATING WIND FARM: A feasibility case study on the Swedish side of the Baltic sea, based on the geographical and wind conditions2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Mathematical modeling and simulations of a submerged renewable storage system integrated to a wind farm, chosen based on the geographical and wind conditions at the Baltic Sea, gives insight on the feasibility of the submerged renewable storage and an approximation of the payback period and profits that could be generated. Genetic Algorithms were used to obtain the optimal number of spheres for a certain depth, based on 2 objective functions I.e. Minimum Life Cycle Cost (LCC) and maximum reduction in wind curtailment. The new arrangement concept shows that the Initial Capital Cost (ICC) could be decreased by 25% to 60% depending upon the number of sphere employed. Based on the inputs considered in the study, the results prove that the submerged renewable storage system would be feasible, and the profits ranging from 15 Million Euro to 29 Million Euro can be achieved at the chosen location, towards the Swedish side of the Baltic sea. Although, in a real life scenario it is assumed that only up to half of the profits obtained in the results would be achievable. The results also show that, the Pump/Turbine with a high turbine efficiency and lower pump efficiency, generated better profits, compared to a Pump/Turbine running with a higher pump efficiency and lower turbine efficiency. An attempt to increase the round-trip efficiency by adding a multi stage submersible pump, resulted in additional ICC and LCC, which saw a decrease in profits. 

  • 247.
    Hoppe, Magnus
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Hallin, Anette
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mörndal, Marie
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Samverkan i det offentliga gränslandet: Utmaningar och möjligheter i samverkan mellan akademi, andra offentliga aktörer och invånare2018Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Arbetet som ligger till grund för den här rapporten har gjorts inom Samverkansprojektet vilket är ett forskningsprojekt som initierats som en del av Samhällskontraktet (SK) och dess delprocess Hållbar samhällsutveckling (HSU). Både SK och HSU är organisatoriska samverkansytor för Västerås stad, Eskilstuna kommun, Region Västmanland, Landstinget Sörmland och Mälardalens högskola.

    Samverkansprojektet har pågått i tre år, mellan 2015 och 2017, i det gränsland som etablerats mellan akademin, våra offentliga samarbetsparter och invånarna, vilket förklarar titeln på rapporten. Vårt konkreta mål med forskningsprojektet har varit att ”utveckla modeller/begrepp som gör det lättare för våra intressenter att förstå de organisatoriska problem de står inför vad gäller att lösa samhällsproblemen de ansvarar för”.

    För att nå målet har flera mindre studier men också andra aktiviteter genomförts. Våra resultat har successivt växt fram och de har också spritts, och fortsätter spridas, på kon­ferenser, seminarier och olika typer av möten likväl som i både akademiska och populära skrifter.

    Våra resultat och erfarenheter presenteras även i denna rapports åtta bidrag, där vi med hjälp av skiftande perspektiv, modeller och begrepp resonerar kring hur samverkan bättre kan förstås och förbättras. Varje kapitel avslutas med rubriken ”Läs mer” där den som vill fördjupa sig i det som tagits upp ges tips om vidare läsning. Rapporten sätter punkt för forskningsprojektet genom att formulera lättillgängliga texter som bygger på olika delar av vårt forskande och samverkande arbete.

    Formen har vi valt för att bidra till ett gemensamt reflekterande hos dig och dem som du vill prata om samverkan med. Istället för färdiga svar, som man ofta hittar som resultat eller slutsatser i mer traditionella rapporter, vill vi att rapporten ska fungera som ett stöd till ett gemensamt utforskande och konstruktionen av gemensamma svar. Att undra tillsammans över problem med hjälp av det vi tar upp i den här rapporten, innebär en jämställd process där var och en bidrar med sitt perspektiv. Rapporten kan på detta sätt ses som ett verktyg för dig som arbetar med samverkan, kanske främst i offentlig sektor.

  • 248.
    Hosain, Md Lokman
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Fluid Flow and Heat Transfer Simulations for Complex Industrial Applications: From Reynolds Averaged Navier-Stokes towards Smoothed Particle Hydrodynamics2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Optimal process control can significantly enhance energy efficiency of heating and cooling processes in many industries. Process control systems typically rely on measurements and so called grey or black box models that are based mainly on empirical correlations, in which the transient characteristics and their influence on the control parameters are often ignored. A robust and reliable numerical technique, to solve fluid flow and heat transfer problems, such as computational fluid dynamics (CFD), which is capable of providing a detailed understanding of the multiple underlying physical phenomena, is a necessity for optimization, decision support and diagnostics of complex industrial systems. The thesis focuses on performing high-fidelity CFD simulations of a wide range of industrial applications to highlight and understand the complex nonlinear coupling between the fluid flow and heat transfer. The industrial applications studied in this thesis include cooling and heating processes in a hot rolling steel plant, electric motors, heat exchangers and sloshing inside a ship carrying liquefied natural gas. The goal is to identify the difficulties and challenges to be met when simulating these applications using different CFD tools and methods and to discuss the strengths and limitations of the different tools.

    The mesh-based finite volume CFD solver ANSYS Fluent is employed to acquire detailed and accurate solutions of each application and to highlight challenges and limitations. The limitations of conventional mesh-based CFD tools are exposed when attempting to resolve the multiple space and time scales involved in large industrial processes. Therefore, a mesh-free particle method, smoothed particle hydrodynamics (SPH) is identified in this thesis as an alternative to overcome some of the observed limitations of the mesh-based solvers. SPH is introduced to simulate some of the selected cases to understand the challenges and highlight the limitations. The thesis also contributes to the development of SPH by implementing the energy equation into an open-source SPH flow solver to solve thermal problems. The thesis highlights the current state of different CFD approaches towards complex industrial applications and discusses the future development possibilities.

    The overall observations, based on the industrial problems addressed in this thesis, can serve as decision tool for industries to select an appropriate numerical method or tool for solving problems within the presented context. The analysis and discussions also serve as a basis for further development and research to shed light on the use of CFD simulations for improved process control, optimization and diagnostics.

  • 249.
    Hosain, Md Lokman
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    TOWARDS ACCELERATED SIMULATIONS FOR FLUID FLOW AND HEAT TRANSFER OF LARGE INDUSTRIAL PROCESSES2016Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Tillverkningsindustrin är en av de största energikonsumenterna.  Järn och stålindustrin i Kina växer väldigt fort. Flera studier har genomförts för att utvärdera den kinesiska stålindustrisektorn vad gäller energieffektivisering och utsläpp av CO2. Resultaten av studierna visade att de stora energibesparingarna som kan genomföras mellan 2020 – 2030 kommer från industriella ugnar i stålverken. För den svenska stålindustrin är det viktigt att vara mycket effektiv för att bibehålla konkurrenskraft. Varmvalsningsprocessen i stålindustrin är en lång process, där stora skivor hettas upp i en ugn över den temperatur där materialet rekristalliseras och metallen valsas sedan i tunna skivor. Skivorna kyls sedan på utrullningsbordet med vatten. Energimängden som används under processen påverkar direkt priset på produkterna. Dessutom kräver stränga statliga bestämmelser, en konkurrenskraftig marknad och bristen på vatten optimala processförhållanden för att reducera energikonsumtionen och utsläppen av klimatgaser. Datasimulering är det bästa och mest pålitliga verktyget att approximera en verkliga processer. Det finns därför ett behov att ha ett online simuleringsverktyg för processoptimering, beslutsstöd och diagnostik i olika industrier.

    CFD-simulering (Computational fluid dynamics) är ett robust simuleringsverktyg för nästan alla typer av verkliga processer relaterade till vätskeflöde, värmeöverföring och förbränning. Dock är simulering av verkliga processer med CFD mycket utmanande på grund av komplexiteten i de fysikaliska fenomenen som ska studeras.  I den här avhandlingen har CFD-simulering använts i liten skala för att förstå fysikaliska egenskaper och komplexiteten i värmningsprocesser av stålskivor och kylningsprocessen av de tunna stålplåtarna vid varmvalsningsprocessen i stålindustrin. Resultaten från simuleringarna är framgångsrikt validerade från experimentella och teoretiska resultat publicerade i litteraturen. Tidigare erfarenheter föreslår nätverksbaserade kommersiella CFD verktyg för att simulera industriella processer om korrekta och detaljerade resultat ska fås. Dock är prestandan för dessa verktyg begränsade ur ett verklighetsperspektiv och indikerar behovet av alternativa CFD-metoder och verktyg. Det första steget i detta arbete var att genomföra en litteraturgenomgång av tidigare studier. Vi identifierade då alternativa metoder som skulle kunna användas för att genomföra CFD-simulering i realtid och i nära realtid för stora industriella processer. Avhandlingen diskuterar begränsningar av olika CFD-metoder och synliggör svårigheter och utmaning i att utnyttja dessa metoder för att simulera stora industriella processer. Vårt preliminära simuleringsarbete är ett litet steg på vägen i målet att producera flerfasiga och multifysikaliska realtidssimuleringar.

  • 250.
    Hosain, Md Lokman
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB AB, Corporate Research, Västerås, Sweden.
    Bel Fdhila, Rebei
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB AB, Corporate Research, Västerås, Sweden.
    Air-Gap Heat Transfer in Rotating Electrical Machines: A Parametric Study2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 4176-4181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    More than half of all electrical energy is consumed by motors and generators in an industrialized country. About 5-25% of this energy is lost and converted to heat. This heat produced by the losses has adverse effect on the lifetime and performance of a machine. A machine has to be operated at a given temperature to achieve maximum efficiency, therefore heat transfer study of machines is of special interest to rotating machines manufacturers. In this paper we investigate the heat transfer in the air-gap between the rotor and the stator of a simplified induction motor using Computational Fluid Dynamics. We consider three different air-gap widths and rotation speeds to explore the change in air-gap heat transfer when changing the air-gap width and the rotation speed. The simulated average heat transfer coefficients for all the models are in good agreement with the correlations from published literature. The Taylor-Couette vortical flow pattern is observed in the air-gap in our simulation results for the models with large air-gaps. The numerical results show that the presence of Taylor-Couette vortices in the air-gap enhance the heat transfer. The heat transfer coefficient increases with the increase in the rotation speed and decreases with the decrease in the air-gap width. 

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