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  • 1.
    Badenes, Borja
    et al.
    Universitat Politècnica de València, Spain.
    Sanner, Burkhard
    UBeG GbR, Germany.
    Mateo Pla, Miguel
    Universitat Politècnica de València, Spain.
    Cuevas, Jose
    Universitat Politècnica de València, Spain.
    Bartoli, Flavia
    SPIN-PET, Italy.
    Ciardelli, Francesco
    SPIN-PET, Italy.
    González, Rosa
    AIMPLAS Plastics Technology Centre, Spain.
    Nejad Ghafar, Ali
    RISE Research Institutes of Sweden, Built Environment, Infrastructure and concrete technology.
    Fontana, Patrick
    RISE Research Institutes of Sweden, Built Environment, Infrastructure and concrete technology.
    Lemus Zuñiga, Lenin
    Universitat Politècnica de València, Spain.
    Urchueguía, Javier
    Universitat Politècnica de València, Spain.
    Development of advanced materials guided by numerical simulations to improve performance and cost-efficiency of borehole heat exchangers (BHEs)2020In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 201, article id 117628Article in journal (Refereed)
    Abstract [en]

    One promising way to improve the efficiency of borehole heat exchangers (BHEs) in shallow geothermal applications is to enhance the thermal properties of the materials involved in its construction. Early attempts, such as using metal tubes in the 1980s or the utilization of thin–foil hoses, did not succeed in being adopted by the market for diverse reasons (cost, corrosion, fragility, etc…). In parallel, the optimization of pipe size, the use of double-U-tubes, thermally enhanced grout, etc. were able to bring the measure for the BHE efficiency, the borehole thermal resistance, from 0.20 to 0.15 K/(Wm) down to 0.08–0.06 K/(Wm) in the best solutions today. A further improvement cannot be expected without development of new, dedicated materials, combining the versatility of plastic like PE with an increased thermal conductivity that matches the respective properties of the rock and soil. This goal was included in the Strategic Research and Innovation Agenda of the European Technology Platform on Renewable Heating and Cooling in 2013. Within an EU supported project, both BHE pipes and grouting materials have been produced prototypically in small amounts, suitable for the first tests in the intended environment. The present work explains the research pathways envisaged and the resulting sensitivity analysis to highlight the influence of some of the most critical parameters that affect the overall performance of a GSHP system. The results have allowed guiding the real development of more efficient new advanced materials for different scenarios representative of different European regions. Finally the developed materials and their properties are discussed, including a comparative assessment about their compliance with reference material properties as currently seen in the BHE market. © 2020 The Author(s)

  • 2.
    Carvalho, Lara
    et al.
    Luleå University of Technology, Sweden.
    Furusjö, Erik
    Luleå University of Technology, Sweden; IVL Swedish Environmental Institute, Sweden.
    Ma, Chunyan
    Luleå University of Technology, Sweden.
    Ji, Xiaojan
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden; IIASA International Institute for Applied Systems Analysis, Austria.
    Hedlund, Jonas
    Luleå University of Technology, Sweden.
    Grahn, Mattias
    Luleå University of Technology, Sweden.
    Öhrman, Olov
    RISE - Research Institutes of Sweden, Bioeconomy, ETC Energy Technology Center. IVL Swedish Environmental Institute, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden;IIASA International Institute for Applied Systems Analysis, Austria.
    Alkali enhanced biomass gasification with in situ S capture and a novel syngas cleaning. Part 2: Techno-economic assessment2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 165, p. 471-482Article in journal (Refereed)
    Abstract [en]

    Previous research has shown that alkali addition has operational advantages in entrained flow biomass gasification and allows for capture of up to 90% of the biomass sulfur in the slag phase. The resultant low-sulfur content syngas can create new possibilities for syngas cleaning processes. The aim was to assess the techno-economic performance of biofuel production via gasification of alkali impregnated biomass using a novel gas cleaning system comprised of (i) entrained flow catalytic gasification with in situ sulfur removal, (ii) further sulfur removal using a zinc bed, (iii) tar removal using a carbon filter, and (iv) CO2 reduction with zeolite membranes, in comparison to the expensive acid gas removal system (Rectisol technology). The results show that alkali impregnation increases methanol production allowing for selling prices similar to biofuel production from non-impregnated biomass. It was concluded that the methanol production using the novel cleaning system is comparable to the Rectisol technology in terms of energy efficiency, while showing an economic advantage derived from a methanol selling price reduction of 2–6 €/MWh. The results showed a high level of robustness to changes related to prices and operation. Methanol selling prices could be further reduced by choosing low sulfur content feedstocks.

  • 3.
    Eriksson, Lina
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Morandin, Matteo
    Chalmers University of Technology, Sweden.
    Harvey, Simon
    Chalmers University of Technology, Sweden.
    Targeting capital cost of excess heat collection systems in complex industrial sites for district heating applications2015In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 91, p. 465-478Article in journal (Refereed)
    Abstract [en]

    The objective of this study is to develop a methodology for estimating the investment costs for heat collection systems gathering excess heat from complex industrial sites and delivering it to a DH (district heating) network. The paper presents a case study conducted on Sweden's largest chemical cluster. In a previous paper, the economic feasibility of delivering heat from the cluster to a regional DH system proved to be favorable under a wide range of price conditions. We develop the methodology used previously in order to identify how each of the plants should contribute to the heat delivery in order to achieve the lowest total investment cost within the cluster. The optimization problem is formulated with the constraint that each plant delivers heat to the DH network separately and at the temperature required by the network. Investments for heat collection systems were estimated for the current configuration of the cluster's energy system (Base case) and for two possible future configurations with increased levels of internal heat recovery. The resulting optimal contribution mix provides a detailed overview of how the plants compete at different specified levels of DH delivery. In the Base case, two plants strongly compete due to similar investment costs.

  • 4.
    Furusjö, Erik
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. IVL Swedish Environmental Institute, Sweden.
    Ma, Chunyan
    Luleå University of Technology, Sweden.
    Ji, Xiaoyan
    Luleå University of Technology, Sweden.
    Carvalho, Lara
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden.
    Alkali enhanced biomass gasification with in situ S capture and novel syngas cleaning. Part 1: Gasifier performance2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 157, p. 96-105Article in journal (Refereed)
    Abstract [en]

    Previous research shows that alkali addition in entrained flow biomass gasification can increase char conversion and decrease tar and soot formation through catalysis. This paper investigates two other potential benefits of alkali addition: increased slag flowability and in situ sulfur capture. Thermodynamic equilibrium calculations show that addition of 2–8% alkali catalyst to biomass completely changes the chemical domain of the gasifier slag phase to an alkali carbonate melt with low viscosity. This can increase feedstock flexibility and improve the operability of an entrained flow biomass gasification process. The alkali carbonate melt also leads to up to 90% sulfur capture through the formation of alkali sulfides. The resulting reduced syngas sulfur content can potentially simplify gas cleaning required for catalytic biofuel production. Alkali catalyst recovery and recycling is a precondition for the economic feasibility of the proposed process and is effected through a wet quench. It is shown that the addition of Zn for sulfur precipitation in the alkali recovery loop enables the separation of S, Ca and Mg from the recycle. For high Si and Cl biomass feedstocks, an alternative separation technology for these elements may be required to avoid build-up.

  • 5.
    Grim, Johanna
    et al.
    Uppsala Vatten och Avfall AB, Sweden.
    Malmros, Peter
    Uppsala Vatten och Avfall AB, Sweden.
    Schnürer, Anna
    SLU Swedish University of Agricultural Sciences, Sweden.
    Nordberg, Åke
    RISE, SP – Sveriges Tekniska Forskningsinstitut, JTI Institutet för Jordbruks- och Miljöteknik. SLU Swedish University of Agricultural Sciences, Sweden.
    Comparison of pasteurization and integrated thermophilic sanitation at a full-scale biogas plant: Heat demand and biogas production2015In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 79, p. 419-427Article in journal (Refereed)
    Abstract [en]

    Sanitation is required for biogas plants handling slaughterhouse and food waste according to EU legislation. The standard method is pasteurization at 70 °C for 60 min, but integrated thermophilic sanitation (ITS), requiring 52 °C for 10 h in the digester, has been approved by the Swedish Board of Agriculture. This work compares pasteurization and ITS regarding heat demand and biogas production, using a full-scale plant in Uppsala, Sweden, as a case study. The plant currently uses pasteurization and thermophilic (52 °C) digestion. The impact of pasteurization on biogas production and process performance was examined at laboratory-scale. The heat demand for pasteurization was surveyed at the full-scale plant, while for ITS a process design was developed and the heat demand was theoretically calculated. The results showed that pasteurization had no significant effect on process performance or biogas production. The heat demand of pasteurization was measured to be 1.92 ± 0.29 MJ (kg VS)−1 (64.7 kWh t−1), while ITS was calculated to require 1.04 MJ (kg VS)−1 (35.1 kWh t−1). This represented 9% and 5% of biogas energy production, respectively. Changing sanitation method to ITS would hence reduce the heat demand at the plant by 46%, corresponding to annual savings of 4380 GJ (1.22 GWh).

  • 6.
    Haegermark, Maria
    et al.
    Chalmers University of Technology, Sweden.
    Kovacs, Peter
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Dalenbäck, Jan-Olof
    Chalmers University of Technology, Sweden.
    Economic feasibility of solar photovoltaic rooftop systems in a complex setting: A Swedish case study2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 127, p. 18-29Article in journal (Refereed)
    Abstract [en]

    An economic feasibility study of solar photovoltaic rooftop (PV) systems in Swedish multifamily buildings was carried out to examine the effects of current market conditions, incentive programmes, and building-specific parameters. Economic analyses were conducted for 108 electricity supply points for scenarios including (1) a tax rebate, (2) an investment subsidy, and (3) both tax rebate and subsidy. First, PV systems were sized and oriented to give the highest net present values, considering actual fuse sizes and hourly demands matched to simulated PV generation. This resulted in shares of profitable systems as follows: 33% with a tax rebate, 51% with a subsidy, and 93% with both. It was shown that the tax rebate programme promotes relatively large systems compared to the subsidy, although with a much higher risk. Thereafter, the influences of main fuse size and existing roofs were investigated. Most of the roofs were large enough to fit the previously sized PV systems. However, taking into account the slopes and directions of available rooftops considerably reduced the number of profitable systems. Finally, the study showed that in addition to support measures and other economic conditions, the PV system feasibility was highly sensitive to roof characteristics, electricity demand and fuse size.

  • 7.
    Isaksson, Johan
    et al.
    Chalmers University of Technology, Sweden.
    Jansson, Mikael
    RISE, Innventia.
    Åsblad, Anders
    CIT Industriell Energi, Sweden.
    Berntsson, Thore
    Chalmers University of Technology, .
    Transportation fuel production from gasified biomass integrated with a pulp and paper mill – Part A: Heat integration and system performance2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 103, p. 557-571Article in journal (Refereed)
    Abstract [en]

    Production of transportation fuels from biorefineries via biomass gasification has been suggested as a way of introducing renewable alternatives in the transportation system with an aim to reduce greenhouse gas emissions to the atmosphere. By co-locating gasification-based processes within heat demanding industries, excess heat from the gasification process can replace fossil or renewable fuels. The objective of this study was to compare the heat integration potential of four different gasification-based biorefinery concepts with a chemical pulp and paper mill. The results showed that the choice of end-product which was either methanol, Fischer-Tropsch crude, synthetic natural gas or electricity, can have significant impact on the heat integration potential with a pulp and paper mill and that the heat saving measures implemented in the mill in connection to integration of a gasification process can increase the biomass resource efficiency by up to 3%-points. Heat saving measures can reduce the necessary biomass input to the biorefinery by 50% if the sizing constraint is to replace the bark boiler with excess heat from the biorefinery. A large integrated gasification process with excess steam utilisation in a condensing turbine was beneficial only if grid electricity is produced at below 30% electrical efficiency. 

  • 8.
    Isaksson, Johan
    et al.
    Chalmers University of Technology, Sweden.
    Jansson, Mikael
    RISE, Innventia.
    Åsblad, Anders
    CIT Industriell Energi, Sweden.
    Berntsson, Thore
    Chalmers University of Technology, Sweden.
    Transportation fuel production from gasified biomass integrated with a pulp and paper mill - Part B: Analysis of economic performance and greenhouse gas emissions2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 103, p. 522-532Article in journal (Refereed)
    Abstract [en]

    This paper presents a comparison between four gasification-based biorefineries integrated with a pulp and paper mill. It is a continuation of ‘Transportation fuel production from gasified biomass integrated with a pulp and paper mill - Part A: Heat integration and system performance’. Synthesis into methanol, Fischer-Tropsch crude or synthetic natural gas, or electricity generation in a gas turbine combined cycle, were evaluated. The concepts were assessed in terms of GHG (greenhouse gas) emissions and economic performance. Net annual profits were positive for all biofuel cases for an annuity factor of 0.1 in the year 2030; however, the results are sensitive to biofuel selling prices and CO2,eq charge. Additionally, GHG emissions from grid electricity are highly influential on the results since all biofuel processes require external power. Credits for stored CO2 might be necessary for processes to be competitive, i.e. storage of separated CO2 from the syngas conditioning has an important role to play. Without CO2 storage, the gas turbine case is better than, or equal to, biofuels regarding GHG emissions. Efficiency measures at the host mill prior to heat integration of a gasification process are beneficial from the perspective of GHG emissions, while having a negative impact on the economy.

  • 9.
    Jafri, Awer
    et al.
    Luleå University of Technology, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden.
    Anheden, Marie
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biorefinery and Energy.
    Kulander, Ida
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biorefinery and Energy.
    Håkansson, Åsa
    Preem AB, Sweden.
    Furusjö, Erik
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biorefinery and Energy.
    Multi-aspect evaluation of integrated forest-based biofuel productionpathways:: Part 2. economics, GHG emissions, technology maturity andproduction potentials2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 172, p. 1312-1328Article in journal (Refereed)
    Abstract [en]

    Promoting the deployment of forest-based drop-in and high blend biofuels is considered strategically important in Sweden but many aspects of the overall performance of the foremost production technologies are as yet unexamined. This paper evaluates the technology maturity, profitability, investment requirements, GHG performance and Swedish biofuel production potential of six commercially interesting forest-based biofuel production pathways.

    Significant heterogeneity in technology maturity was observed. Lack of technical demonstration in industrially representative scales renders the liquefaction-hydrotreatment route for drop-in biofuels less mature than its gasification-catalytic upgrading counterpart. It is a paradox that short-term priority being accorded to pathways with the lowest technology maturity. Nth-of-a-kind investments in (a) gasification-based methanol, (b) hydropyrolysis-based petrol/diesel, and (c) lignin depolymerization-based petrol/diesel were profitable for a range of plant sizes. The profitability of pulp mill-integrated small gasification units (<100 MW) goes against the common perception of gasification being economically feasible only in large scales. New low-cost options for debottlenecking production at recovery boiler-limited kraft mills appear worth investigating. GHG emission reductions ranged from 66 to 95%; a penalty was incurred for high consumption of natural gas-based hydrogen. Swedish biofuel production potentials ranged from 4 to 27 TWh/y but a more feasible upper limit is 12–15 TWh/y.

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  • 10.
    Jafri, Yawer
    et al.
    Luleå University of Technology, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden.
    Anheden, Marie
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Håkansson, Åsa
    Preem AB, Sweden.
    Furusjö, Erik
    Luleå University of Technology, Sweden ; IVL Swedish Environmental Research Institute, Sweden.
    Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 1. Product yields & energetic performance2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 166, p. 401-413Article in journal (Refereed)
    Abstract [en]

    Forest-based biofuels are strategically important in forest-rich countries like Sweden but the technical performance of several promising production pathways is poorly documented. This study examines product yields and energy efficiencies in six commercially relevant forest-based “drop-in” and “high blend” biofuel production pathways by developing detailed spreadsheet energy balance models. The models are in turn based on pilot-scale performance data from the literature, supplemented with input from technology developers and experts. In most pathways, biofuel production is integrated with a market pulp mill and/or a crude oil refinery. Initial conversion is by pyrolysis, gasification or lignin depolymerization and intermediate products are upgraded by hydrotreatment or catalytic synthesis. While lignin oil (LO) hydrodeoxygenation had the highest expanded system efficiency, considerable uncertainty surrounds product yields owing to absence of suitable experimental data on LO upgrading. Co-feeding vacuum gas oil and fast pyrolysis oil in a fluidized catalytic cracker has a complex and uncertain effect on fossil yields, which requires further investigation. Co-locating bio-oil hydrotreatment at the refinery improves heat utilization, leading to higher system efficiencies. Explicit consideration of mill type and energy requirements is required to avoid performance misestimation as an assumption of energy surplus can confer a definite advantage.

  • 11.
    Lindhe, Jonas
    et al.
    Lund University, Sweden.
    Larsson, Martin
    RISE Research Institutes of Sweden, Built Environment, Energy and Resources.
    Willis, Morgan
    RISE Research Institutes of Sweden, Built Environment, Energy and Resources.
    Tiljander, Pia
    RISE Research Institutes of Sweden, Built Environment, Energy and Resources.
    Johansson, Dennis
    Lund University, Sweden.
    Challenges and potentials of using a local heat pump in a 5 GDHC solution: Results from field and laboratory evaluations2024In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 289, article id 129807Article in journal (Refereed)
    Abstract [en]

    In fifth generation district heating and cooling (5GDHC), the temperature range of the heat source is wider then in current common heat pump systems. The results of this study show that the heat pumps and chillers that are available in the market are not well adapted to 5GDHC applications due to the wide working range of 5GHDC. In order to maintain a high efficiency, current design parameters should be adjusted. This affects the dimensioning of all components in the refrigerant circuit and the required volume of refrigerant. An operational challenge specific to 5GDHC occurs when there is a low power demand at a relatively low temperature (eg. 35 °C) on the condenser side that coincides with a relatively high temperature (eg. 25 °C) on the evaporator side, resulting in a high thermal power during times with limited demand. Since the 5GDHC distributes both cooling and heating, it is also a challenge to successfully control the local heat pump in order that it fulfils the demands on both the hot and cold side. The heat pumps connected to 5GDHC systems have the potential to reach a high coefficient of performance (COP), due to the high temperature of the heat source. The challenge is to maintain a high COP throughout operation. At the ends of the heat pumps operational temperature range, the efficiency tends to drop considerably, resulting in a low System Efficiency Index compared to operations well within the operational range. This research seeks to address these challenges by highlighting better design principles in order to realize the untapped potential of 5GDHC systems. This is performed by investigating the influence of individual components on the performance of a local heat pump installed in a 5GDHC grid, assessed through theoretical simulations, field tests and laboratory measurements.

  • 12.
    Lionello, M.
    et al.
    University of Padova, Italy.
    Rampazzo, M.
    University of Padova, Italy.
    Beghi, A.
    University of Padova, Italy.
    Varagnolo, D.
    NTNU Norwegian University of Science and Technology, Norway.
    Vesterlund, Mattias
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Graph-based modelling and simulation of liquid immersion cooling systems2020In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 207, article id 118238Article in journal (Refereed)
    Abstract [en]

    Currently, most of the existing data centers use chilled air to remove the heat produced by the servers. However, liquids have generally better heat dissipation capabilities than air, thus liquid cooling systems are expected to become a standard choice in future data centers. Designing and managing these cooling units benefit from having control-oriented models that can accurately describe the thermal status of both the coolant and the heat sources. This manuscript derives a control-oriented model of liquid immersion cooling systems, i.e., systems where servers are immersed in a dielectric fluid having good heat transfer properties. More specifically, we derive a general lumped-parameters gray box dynamical model that mimics energy and mass transfer phenomena that occur between the main components of the system. The proposed model is validated against experimental data gathered during the operation of a proof-of-concept immersion cooling unit, showing good approximation capabilities. 

  • 13.
    Ljungqvist, Hampus Markeby
    et al.
    Luleå University of Technology, Sweden.
    Mattsson, Louise
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Risberg, Mikael
    Luleå University of Technology, Sweden.
    Vesterlund, Mattias
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Data center heated greenhouses, a matter for enhanced food self-sufficiency in sub-arctic regions2021In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 215, article id 119169Article in journal (Refereed)
    Abstract [en]

    This paper examines the possibility of increasing Northern Sweden's degree of self-sufficiency in food supply, at the 65th latitude, by using a data center as a heating source for greenhouse production. A dynamic building energy simulation software was used to compute both the hourly exhaust air output from a 1 MW data center for one year and the corresponding heating demand for two different greenhouse sizes, 2000 m2 and 10 000 m2, and two different production scenarios. Partial year production, 1 Mars – 15 October, without grow lights and full-year production with grow lights. The study showed that 5.5–30.5% of the electrical input to a 1 MW data center could be recovered. The 2000 m2 greenhouse could operate almost entirely, 89.7–97.9%, on excess heat while only 50.0–61.5% of the 10 000 m2 greenhouse heating demand could be met for full- and partial-year production, respectively. Furthermore, it is concluded that the 10 000 m2 greenhouse with full year production was the most prominent case and would cost-effectively yield 7.6% of northern Sweden's vegetable self-sufficiency.

  • 14.
    Lo Cascio, Ermanno
    et al.
    Università degli Studi di Genova, Italy.
    Puig von Friesen, Marc
    RISE - Research Institutes of Sweden, Built Environment.
    Schenone, Corrado
    Università degli Studi di Genova, Italy.
    Optimal retrofitting of natural gas pressure reduction stations for energy recovery2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, ISSN 0360-5442, Vol. 153, p. 387-399Article in journal (Refereed)
    Abstract [en]

    In this paper, a structured retrofitting approach (SRA) to the near-optimal design of natural gas (NG) pressure reduction stations (PRSs) is presented. The SRA is designed by considering the waste energy recovery, system integration opportunities and long-term-based objectives to successfully address the entire PRS retrofitting process. The SRA is developed in four phases: pre-retrofit activities, preliminary and executive project design, implementation and commissioning and post-retrofit activities. For design optimization during the preliminary and executive project design phase, a novel mathematical model was developed based on the minimization of the levelized cost of energy (LCOE). The optimization model consists of a non-smooth constrained problem that has been solved by means of different solution methods and has been tested for different thermal peak loads, fuel purchase costs, and natural gas flow rates. Variations of the thermal design conditions from 2900 kW to 1300 kW for a constant annual heat demand, fluctuations of the percentage increase of the NG cost by 80-100-120-140%, and reductions of the NG user demand of 30% and 60% were considered. The results highlighted that the proposed optimization technique in PRS retrofitting identifies the best system configuration and turbo expander technology.

  • 15.
    Mardan, N.
    et al.
    Linköping University.
    Klahr, Roger
    RISE, Swerea, Swerea SWECAST.
    Combining optimisation and simulation in an energy systems analysis of a Swedish iron foundry2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 44, no 1, p. 410-419Article in journal (Refereed)
  • 16.
    Persson, H.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Han, T.
    KTH Royal Institute of Technology, Sweden.
    Sandström, Linda
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, ETC Energy Technology Center.
    Xia, W.
    KTH Royal Institute of Technology, Sweden.
    Evangelopoulos, Panagiotis
    KTH Royal Institute of Technology, Sweden.
    Yang, W.
    KTH Royal Institute of Technology, Sweden.
    Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 154, p. 346-351Article in journal (Refereed)
    Abstract [en]

    The thermal properties of cellulose, hemicellulose and lignin can be utilized to improve the characteristics of pyrolysis liquids. In this study, a concept of stepwise pyrolysis to fractionate the liquid based on the thermal properties of the biomass constituents was investigated. Lignocellulosic biomass was thermally treated in two steps: 200–300 °C followed by 550 °C. Derived liquids were studied for GC/MS analysis, water content, acid concentration and a solvent extraction method. Pyrolytic liquid derived from 550 °C after treatment at lower temperatures have a higher relative composition of phenolic compounds compared to one-step pyrolysis (increased from 58 to 90% of GC/MS peak area). Also, compounds known to promote aging, such as acids and carbonyl compounds, are derived at lower temperatures which may suppress aging in the liquid derived downstream at 550 °C. For liquids derived at 550 °C, the total acid number was reduced from 125 in one-step treatment to 14 in two-step treatment. Overall, no significant difference in the total liquid yield (sum of the liquids derived in separated treatments) nor any variations in their collective composition compared to one-step treatment at 550 °C was observed, i.e. stepwise pyrolysis can be utilized for direct fractionation of pyrolytic vapors.

  • 17.
    Ringkjøb, Hans-Kristian
    et al.
    University of Bergen, Norway; Institute for Energy Technology, Norway; IIASA International Institute for Applied Systems Analysis, Austria.
    Haugan, Peter
    University of Bergen, Norway.
    Seljom, Pernille
    Institute for Energy Technology, Norway.
    Lind, Arne
    Institute for Energy Technology, Norway.
    Wagner, Fabian
    IIASA International Institute for Applied Systems Analysis, Austria.
    Mesfun, Sennai
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy. IIASA International Institute for Applied Systems Analysis, Austria.
    Short-term solar and wind variability in long-term energy system models - A European case study2020In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 209, article id 118377Article in journal (Refereed)
    Abstract [en]

    Integration of variable renewables such as solar and wind has grown at an unprecedented pace in Europe over the past two decades. As the share of solar and wind rises, it becomes increasingly important for long-term energy system models to adequately represent their short-term variability. This paper uses a long-term TIMES model of the European power and district heat sectors towards 2050 to explore how stochastic modelling of short-term solar and wind variability as well as different temporal resolutions influence the model performance. Using a stochastic model with 48 time-slices as benchmark, the results show that deterministic models with low temporal resolution give a 15–20% underestimation of annual costs, an overestimation of the contribution of variable renewables (13–15% of total electricity generation) and a lack of system flexibility. The results of the deterministic models converge towards the stochastic solution when the temporal resolution is increased, but even with 2016 time-slices, the need for flexibility is underestimated. In addition, the deterministic model with 2016 time-slices takes 30 times longer to solve than the stochastic model with 48 time-slices. Based on these findings, a stochastic approach is recommended for long-term studies of energy systems with large shares of variable renewable energy sources. © 2020 The Authors

  • 18.
    Shi, Z.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Jin, Y.
    KTH Royal Institute of Technology, Sweden.
    Svanberg, R.
    KTH Royal Institute of Technology, Sweden.
    Han, T.
    KTH Royal Institute of Technology, Sweden.
    Minidis, Alexander
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Kindstedt Danielsson, Ann-Sofi
    RISE Research Institutes of Sweden, Bioeconomy and Health, Chemical Process and Pharmaceutical Development.
    Kjeldsen, C.
    Topsoe A/S, Denmark.
    Jönsson, P. G.
    KTH Royal Institute of Technology, Sweden.
    Yang, W.
    KTH Royal Institute of Technology, Sweden.
    Continuous catalytic pyrolysis of biomass using a fluidized bed with commercial-ready catalysts for scale-up2023In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 273, article id 127288Article in journal (Refereed)
    Abstract [en]

    The use of catalytic fast pyrolysis (CFP) of biomass to produce high-quality bio-oils as potential substitutes for conventional fuels plays an essential role in the decarbonization of the world. In this study, continuous CFP tests of sawdust using three commercial-ready catalysts were performed. The overall objective is to screen appropriate catalysts and catalyst loading amounts for further commercialization and upgrading by evaluating the quality of the organic fraction bio-oils and clarifying the relationship between the hydrogen-to-carbon atomic effective (H/Ceff) ratio and bio-oil yield. The results displayed that, owing to a cracking effect of the catalyst, all catalytic cases had higher H/Ceff ratios and larger relative area percentages of hydrocarbons determined by NMR. Thermogravimetric analysis reveals that, compared to non-catalytic bio-oils, catalytic bio-oils showed more distillates in the diesel range. Increasing the catalyst-loading amount also showed the same effect. Overall, all bio-oil products from catalytic cases had H/Ceff ratios higher than 0.6, indicating the production of promising oil for hydrodeoxygenation. By analyzing and fitting the data from this work and comparing with the literature, it could be concluded that its yield would decrease as the bio-oil product quality increases (the H/Ceff ratios increase). © 2023 The Authors

  • 19.
    Wang, Guangwei
    et al.
    University of Science and Technology Beijing, China.
    Zhang, Jianliang
    University of Science and Technology Beijing, China.
    Chang, Weiwei
    University of Science and Technology Beijing, China.
    Li, Rongpeng
    University of Science and Technology Beijing, China.
    Li, Yanjiang
    University of Science and Technology Beijing, China.
    Wang, Chuan
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. Åbo Akademi University, Finland.
    Structural features and gasification reactivity of biomass chars pyrolyzed in different atmospheres at high temperature2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 147, p. 25-35Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the gasification properties of biomass chars obtained under different conditions by using non-isotherm thermogravimetric method. The physical and chemical structure features were also systematically studied. It shows that the gasification reactivities decrease with increasing pyrolysis temperature, and the gasification reactivities for the chars obtained under different atmosphere conditions are in the order of N2 char &gt; CO2 char &gt; CO char &gt; H2 char. The gasification reactivities of the chars are mostly depend on the carbonaceous structure. Three nth-order represented gas-solid models, i.e. Random pore model (RPM), Unreaction core model (URCM) and Volumetric model (VM), were used to describe the reactive behaviors, and it indicates that the RPM is more suitable than the other two models.

  • 20.
    Wang, Haichao
    et al.
    Dalian University of Technology, China; Aalto University, Finland.
    Zhou, Yang
    Dalian University of Technology, China.
    Li, Xiangli
    Dalian University of Technology, China.
    Wu, Xiaozhou
    Dalian University of Technology, China.
    Wang, Hai
    Tongji University, China.
    Elnaz, Abdollahi
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Granlund, Katja
    Planora Oy, Finland.
    Lahdelma, Risto
    Aalto University, Finland.
    Teppo, Esa
    Planora Oy, Finland.
    Study on the performance of a forced convection low temperature radiator for district heating2023In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 283, article id 129036Article in journal (Refereed)
    Abstract [en]

    Low temperature district heating has significant advantages in energy efficiency, but a huge amount of existing radiators lack the capabilities for low-temperate heating. The innovation of this study is to develop an optimal and techno-economic method to improve the heating power of existing radiator by mounting a small fan considering different hydraulic connection modes. An experimental test rig was designed to study the optimal installation positions and angles of the fan. For a dormitory room in China, a computational fluid dynamics (CFD) model was developed and verified. The model was used to determine the lowest supply temperature of the radiator. Results show that the fan should be placed in a position and angle that blows air over the hottest surface of the radiator i.e. the hot center. The lowest supply temperatures before and after installing the fan are 42.3 °C and 39.5 °C. The response speed is increased by 28%, stability time is shortened by 13%, while the maximum indoor temperature difference is reduced by 15% and the maximum indoor air velocity is reduced by 0.07 m/s. Payback time is 63 days for case study, indicating a good economic feasibility. The method is beneficial to both the heat plant and users. 

  • 21.
    Zetterholm, Jonas
    et al.
    Luleå University of Technology, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden; IIASA International Institute for Applied Systems Analysis, Austria.
    Pettersson, Karin
    RISE - Research Institutes of Sweden (2017-2019), Built Environment, Energy and Circular Economy.
    Lundgren, Joakim
    Luleå University of Technology, Sweden ; IIASA International Institute for Applied Systems Analysis, Austria.
    Evaluation of value chain configurations for fast pyrolysis of lignocellulosic biomass - Integration, feedstock, and product choice2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 144, p. 564-575Article in journal (Refereed)
    Abstract [en]

    Fast pyrolysis of lignocellulosic biomass constitutes a promising technology to reduce dependence on fossil fuels. The product, pyrolysis liquids, can either substitute heavy fuel oil directly, or be upgraded via e.g. hydroprocessing to diesel and petrol. This study presents a systematic evaluation of production costs and CO2 mitigation potentials of different fast pyrolysis value chain configurations. The evaluation considers types of localisations, emissions from electricity and hydrogen production, biomass feedstocks, and final products. The resulting production costs were found to be in the range of 36–60 EUR/MWh for crude pyrolysis liquids, and 61–90 EUR/MWh upgraded to diesel and petrol. Industrial integration was found to be favoured. The CO2 mitigation potential for the pyrolysis liquids was in the range of 187–282 t-CO2/GWh biomass. High variations were found when upgraded to diesel and petrol –best-case scenario resulted in a mitigation of 347 t-CO2/GWh biomass, while worst-case scenarios resulted in net CO2 emissions. Favourable policy support, continued technology development, and/or increased fossil fuel prices are required for the technology to be adapted on an industrial scale. It was concluded that integration with existing industrial infrastructure can contribute to cost reductions and thus help enable the transformation of traditional forest industry into biorefineries.

1 - 21 of 21
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