| 1. |
- Yan, Jinyue, et al.
(författare)
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CO2 capture with the absorbent of a mixed ionic liquid and amine solution considering the effects of SO2 and O2
- 2017
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 194, s. 9-18
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Tidskriftsartikel (refereegranskat)abstract
- Room-temperature ionic liquids (ILs) have recently been proposed as a potential candidate for CO2 capture. In this study, experiments were conducted in an absorption-desorption loop system to investigate the effects of SO2 and O2 on CO2 capture using an aqueous amine solution mixed with IL. The gas mixture containing CO2, O2, SO2 and N2 in the composition range of flue gas from a coal-fired power plant after flue gas desulfurization was selected as the feed gas. It was found that the addition of hydrophilic IL of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) to a monoethanolamine (MEA) aqueous solution reduced the losses of MEA and water by lowering the saturated vapour pressure of the mixed absorbent. For hydrophobic IL of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]), the MEA loss for 30 wt% MEA + 70 wt% [hmim][Tf2N] increased dramatically with the system running because carbonate, which was formed by MEA reacting with CO2, was insoluble in [hmim][Tf2N] at the absorber operation temperature of 323 K. The effects of O2 and SO2 were relatively insignificant for the MEA and water losses. The aqueous amine solution mixed with [bmim][BF4] showed good performances with a CO2 removal efficiency of above 90% and the SO2 concentration at the absorber outlet below 20 ppb. No obvious IL loss was detected. For the absorbent of 30 wt% MEA + 50 wt% [bmim][BF4] + 20 wt% H2O, the thermal energy consumption for absorbent regeneration is 33.8% lower than that of the aqueous MEA solution.
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| 2. |
- Zhang, Chi, et al.
(författare)
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Can Solar Energy be an Alternative Choice of Milk Production in Dairy Farms? : -A Case study of Integrated PVWP System with Alfalfa and Milk Production in Dairy Farms in China
- 2017
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Ingår i: 8th International Conference on Applied Energy, ICAE 2016; Beijing; China; 8 October 2016 through 11 October 2016. - : Elsevier. ; 105, s. 3953-3959
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Konferensbidrag (refereegranskat)abstract
- As China's dairy consumption grows, both the domestic milk production and the importation of dairy products are increasing to meet market demands. The objective of this study was to quantify electricity usage and cost of milk production with data analysis of dairy farms and evaluate the potential alternative energy supply-solar energy generated by PV water pumping system (PVWP). We collected data in milk production processes from 11 dairy farms in China. By selecting the optimal dairy farm, we simulate the scenario of solar power generation with PVWP system to provide power both for milk and alfalfa production. With estimations of electricity saving, economic cost saving and CO2 saving on every kg milk produced under PVWP system, we conclude that scenario PVWP with alfalfa and milk production can results in value add-ins, new sources of revenue, energy supply and emission reductions.
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| 3. |
- Zhang, Chi, et al.
(författare)
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Crowdfunding preferences for a sustainable milk product with integrated photovoltaic water pumping system in China
- 2019
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 255
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies the role of potential investors in financing renewable energy systems—specifically, relating to crowdfunding as a financing mechanism, with the enhancement of internet and social-media tools. The research question in this study is whether crowdfunding with a novel socio-technical product reward program attracts potential customers to a more sustainable milk product with a specific integrated photovoltaic water pumping (PVWP) system. The particular case study we empirically investigated is product reward crowdfunding in dairy milk production in China. The milk production chain was supplied by PVWP system integration, which generated solar energy both for feed production for dairy cows and for the operation of dairy farms. 48 semi-structured in-depth interviews were conducted between the research team and customers in order to perform qualitative analyses of the determinants of customers’ milk purchase behaviors. In addition, 357 online surveys were collected for quantitative analysis. Binary and ordered probit regressions were employed to use survey date to systematically estimate purchase intention and willingness-to-pay for sustainable milk. Customer behaviors, environmental consciousness, and individual socio-demographic factors were investigated as potential explanatory variables. Over 82% of the survey participants showed intentions to purchase the sustainable milk with the PVWP system. In the survey and interview samples, results showed that milk quality, nutrition improvement, emissions reduction, and environmental benefits attributed to the integrated PVWP system were the major factors considered by interviewees who showed intentions to purchase the crowdfunded dairy milk. Regression model results suggested that potential customers with higher income levels, and those of parenting age, and those with young children or planning to have children, had a higher willingness-to-pay than other customers for the crowdfunded sustainable dairy milk. The familiarity with and popularity of online shopping and pre-sale purchases in China made customers more open to and proactive towards pre-pay and crowdfunding mechanisms. This article evaluated key factors which may influence potential customers for crowdfunding, and used a discrete choice model to estimate customers’ willingness-to-pay for reward-based projects. These results could help producers of sustainable milk products to identify potential target groups in China and estimate market demand. This exploratory study could provide a framework with both quantitative and qualitative assessment of crowdfunding for renewable energy systems in a national or international context.
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| 4. |
- Dahlquist, Erik, 1951-, et al.
(författare)
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Combined Solar Power, Hydrogen, TPV and Cyanobacter Production
- 2010
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Ingår i: Proceedings of the International Conference of Applied Energy. ; , s. 179-188
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Konferensbidrag (refereegranskat)abstract
- In this paper we discuss design for a combined TPV and solar power system with production of biomass. During the passage through the solar collector cyanobacters or algae are getting sunshine to drive the photo synthesis. An algae suspension is circulated through a solar panel to drive photo synthesis. The flow rate is varying with solar intensity to balance the temperature increase. This is to avoid inhibition of the cyanobacters/algae growth rate due to too high temperature. PV cells are producing electricity when there is light, while TPV cells are used when it is dark. The biomass produced then is utilized for production of photons for the TPV system. As an alternative a system producing Hydrogen and electricity produced in a fuel cell system is discussed. Design criteria for the systems are discussed in this paper for a house that is principally self sufficient on energy. Both theoretical and practical obstacles are discussed, as there are a number of issues to solve before the technique can be used in ”real life”
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| 5. |
- Campana, Pietro Elia, et al.
(författare)
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Managing agricultural drought in Sweden using a novel spatially-explicit model from the perspective of water-food-energy nexus
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 197, s. 1382-1393
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Tidskriftsartikel (refereegranskat)abstract
- Using a multi-disciplinary approach, this paper integrated spatial analysis with agricultural and energy system modelling to assess the impacts of drought on crop water demand, water availability, crop yield, and electricity requirements for irrigation. This was done by a novel spatially-explicit and integrated water-food-energy nexus model, using the spatial climatic data generated by the mesoscale MESAN and STRANG models. In this study, the model was applied to quantify the effects of drought on the Swedish irrigation sector in 2013, a typical drought year, for a specific crop. The results show that drought can severely affect the crop yield if irrigation is not applied, with a peak yield reduction of 18 t/ha, about 50 % loss as compared to the potential yield in irrigated conditions. Accordingly, the water and energy requirements for irrigation to halt the negative drought effects and maintain high yields are significant, with the peaks up to 350 mm and 700 kWh per hectare. The developed model can be used to provide near real-time guidelines for a comprehensive drought management system. The model also has significant potentials for applications in precision agriculture, especially using high-resolution satellite data.
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| 6. |
- Guziana, Bozena, 1963-, et al.
(författare)
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SCENARIOS FOR WASTE-TO-ENERGY USE - SWEDISH PERSPECTIVE.
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of waste for energy purposes becomes increasingly interesting both with respect to waste management and for 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 at national level, shall be carefully considered and addressed. This paper proposes scenarios for waste to energy systems with focus on Sweden and with a broader EU approach is applied: Biofuels Sweden, Electric vehicles and Bioenergy Europe. As baseline for the scenario development 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. A low waste availability level is recommended to be included in sensitivity analysis for scenarios.
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| 7. |
- Campana, Pietro Elia, 1984-, et al.
(författare)
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Li-ion batteries for peak shaving, price arbitrage, and photovoltaic self-consumption in commercial buildings : A Monte Carlo Analysis
- 2021
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 234
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the benefits of introducing Li-ion batteries as energy storage unit in the commercial sector by considering a representative building with a photovoltaic system. Only the costs and revenues related to the installation and operation of the battery are considered in this study. The operational strategy of the battery consists in balancing the following processes through day-ahead forecasts for both electricity consumption and photovoltaic production: shaving a targeted peak, performing price arbitrage, and increasing photovoltaic selfconsumption. By reviewing the electricity price cost for commercial buildings from several companies around the world, a general electricity price structure is defined. Afterwards, a Monte Carlo Analysis is applied for three locations with different solar irradiation levels to study the impact of climate, electricity price components, and other seven sensitive parameters on the economic viability of Li-ion batteries. The Monte Carlo Analysis shows that the most sensitive parameters for the net present value are the battery capacity, the battery price, and the component of the electricity price that relates to the peak power consumption. For Stockholm, one of the investigated locations, the corresponding Pearson correlation coefficients are -0.67, -0.66, and 0.19 for the case were no photovoltaic system is installed. For the considered battery operational strategies, the current investment and annual operation costs for the Li-ion battery always lead to negative net present values independently of the location. Battery prices lower than 250 US$/kWh start to manifest positive net present values when combining peak shaving, price arbitrage, and photovoltaic self-consumption. However, the integration of a photovoltaic system leads to a reduced economic viability of the battery by reducing the revenues generated by the battery while performing peak shaving.
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| 8. |
- Li, Hailong, 1976-, et al.
(författare)
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A new modification on RK EOS for gaseous CO2 and gaseous mixtures of CO2 and H2O
- 2006
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 30:3, s. 135-148
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Tidskriftsartikel (refereegranskat)abstract
- To develop an equation of state with simple structure and reasonable accuracy for engineering application, Redlich-Kwong equation of state was modified for gaseous CO2 and CO2-H2O mixtures. In the new modification, parameter 'a' of gaseous CO2 was regressed as a function of temperature and pressure from recent reliable experimental data in the range: 220-750 K and 0.1-400 MPa. Moreover, a new mixing rule was proposed for gaseous CO2-H2O mixtures. To verify the accuracy of the new modification, densities were calculated and compared with experimental data. The average error is 1.68% for gaseous CO2 and 0.93% for gaseous mixtures of CO2 and H2O, Other thermodynamic properties, such as enthalpy and heat capacities of CO2 and excess enthalpy of gaseous CO2-H2O mixtures, were also calculated; results fit experimental data well, except for the critical region.
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| 9. |
- Lo Zupone, Giacomo, et al.
(författare)
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Understanding the development and interaction of wake induced by an open centre turbine and its array design implications
- 2022
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Ingår i: Applied Ocean Research. - : Elsevier BV. - 0141-1187 .- 1879-1549. ; 129
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Tidskriftsartikel (refereegranskat)abstract
- The open centre turbine can be easily deployed with a kite-like mooring system, which is promising to harvest renewable marine resources due to its higher energy conversion efficiency, and lower cost, as well as the min-imum impacts on the submarine environment. However, the multi-turbines deployment is still a great challenge due to the interaction between the wake flow generated by each device. Understanding the wake development is critical to implementing a strategy for multi-turbine deployment and minimizing the impact of the array on the submarine environment, the shore bed and the coast.This work aims to define the wake morphology and the multi-device configuration for the open centre turbines by applying the computational fluid dynamic (CFD) analysis, and the Jensen model, validated by scaled ex-periments for traditional turbines.The first step of the research deals with a stand-alone fully resolved turbine geometry. The annular rotor works like a Venturi channel: the flow passing through the central hole rises its velocity and reduces the pressure behind the rotor plane. The induced suction effect reduces the tangential flow velocity components, containing either the wake radial expansion to 1.6R (turbine radius) and axial extension to 6D (turbine diameter). The wake takes a cylindrical shape and the flow field outside this cylinder can be assumed as undisturbed.The second step of research deals with the study of an optimal multi-device layout. The parameters to be found are the distance between rotors' rows and turbines' wheelbase, under the condition that the power of each turbine is almost equal. For a 2 staggered turbines layout, a wheelbase of 3D and a distance between rows of 5D allow for keeping the devices' performances constant, being, in both cases, the array Cp = 0.414. For 3 turbines in two staggered rows, the optimal configuration is characterized by a wheelbase of 1.5D and a distance between rows of 3D, with an array Cp = 0.413.The key to this performance is the cylindrical wake generated by the open centre rotor geometry: in the multi -device configuration any turbine is decoupled, so there is no mutual disturbance even at reduced inter-device clearances.
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| 10. |
- Wang, Limin, et al.
(författare)
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Investigation on a novel post-combustion CO2 capture rotary adsorption wheel based on temperature swing adsorption
- 2024
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Ingår i: International Journal of Green Energy. - : TAYLOR & FRANCIS INC. - 1543-5075 .- 1543-5083.
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Tidskriftsartikel (refereegranskat)abstract
- Due to the strengths on compact structure and continuously operating ability, a rotary wheel device in rotating packed-bed configuration for adsorption process based on temperature swing has been proposed to achieve CO2 capture in engineering application. The 3D simulations of the rotary adsorption wheel for post-combustion CO2 capture based on non-equilibrium model have not been reported. In this study, considering the non-equilibrium of heat and mass transfer, the mathematical modeling was performed for temperature swing adsorption process in the rotary bisectional adsorption wheel for the cooling-and-feeding process and rinsing-and-heating process. Comparison with the experimental breakthrough data on the fixed packed-bed was performed to validate the model. Distributions of temperature and mass fraction in the rotary adsorption wheel were obtained in three dimensions, based on which a reasonable arrangement of fluid ducting should be set to meet the different concentration requirement of CO2 capture. There is an optimal rotating speed to make the adsorption-outlet N-2 concentration as high as possible and the desorption-outlet N-2 concentration as low as possible. Whether considering the adsorption enthalpy or not in the model can greatly impact the heat and mass transfer characteristics of rotary adsorption wheel. The effects of other parameters including particle size, porosity and adsorbent materials will be further analyzed in the future study.
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