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  • 2651.
    Zanforlini, Lucas Waldem
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    The Impact of Remittances on the Economic Growth of Developing Countries: A Literature Review2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Firms, financial institutions and governments have been the main source for international

    financial flows to developing countries. Moreover, from the late 1990s remittances sent from

    migrants abroad to their home countries became a vital source of income as they exceed

    official development assistance or aids.

    Our interest concerns on how remittances affect economic growth in developing countries.

    However, we have come across considerable contradictory findings regarding the positive or

    negative contribution of remittances to a sustainable economic development.

    A main obstacle in detecting the effect on economic growth is due to the problem of

    measuring the real financial flows across countries and to the informal channels migrants use

    to send money.

    Unlike many studies, which are based on empirical method, this paper is based on a literature

    review as we are interested in a broader overview of the subject.

    Comparing various findings, we conclude that remittances contribute positively to economic

    growth.

    The level of contribution is based on how remittance receiving families use the inflows of

    money inflows. Both physical and human investment have a larger impact on the economic

    growth in a long-term perspective, while direct consumption on primary goods activate a

    multiplier effect of aggregate demand which results beneficial to the entire economy.

    Particularly attention is dedicated to the need of policy interventions to optimize the positive

    impact of remittances and prevent their possible bad side effects.

  • 2652.
    Zarifnejad, Sirwan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Johansson, Petra
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Nudge Management; a way to Motivate Healthier Behavior2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today, organizations are facing rising costs caused by increased employee sick - leave. A way to motivate employees to choose a healthier lifestyle is for the employer to offer wellness incentives. However, not too many employees are taking advantage of the incentives. According to the Transtheoretical Model of Health Behavior Change (TTM) , people are at different stages in their behavior change process. By knowing their personal obstacles to change, organizations can use nudge management and wellness incentives to help their employees to choose a healthier lifestyle. In order to get some answers, we conducted qualitative interviews at the Swedish Migration Agency. The result of our research showed seven main obstacles, and in this thesis we have explored dif erent nudges organizations can use to promote health and to lower sick - leave.

  • 2653.
    Zaytoun, Josefin
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Ghazal, Sandra
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Rafael, Raneen
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Penningtvätt: Ur en revisors perspektiv2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 2654.
    Zeng, Lei
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A Policy Analytical Approach of Assessing Energy Efficiency Standards and Labeling for Appliances2015Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    China is the world’s largest producer and consumer of household appliances, lighting and commercial equipment. China first adopted Minimum Energy Performance Standards (MEPS) in 1989. By 2013, China has developed and implemented 52 Energy Efficiency Standards (EES) and 28 mandatory energy labels for a wide range of domestic, commercial, and selected industrial equipment. However, despite of the large number of standards issued, big challenges remain with how to ensure the standards keep up with the dynamic evolvement of technologies and appliance market after they enter effect.

    The current policy analysis methods adopted by the policy makers primarily focuses on standards making process and very limited attentions were paid on impact assessment and ex-post evaluation of standards and labeling systems, hence the effectiveness of active Energy Efficiency Standards has not been assessed timely and comprehensively. One major barrier of this is the lacking of assessment methods and market data.

    This thesis intends to tackle the above issues by developing a new policy analysis approach that can be used to assess the impact of energy efficiency standards and labeling with market data. This approach adopts a comprehensive analysis method that comprises three components: (1) Analysis of market data; (2) Quantification of energy savings potential; and (3) Benchmarking China’s EE standards to those of peer economies around the world. This integrated approach leads to three independent but complementary studies that provide evidence-based findings and policy recommendations for the improvement of China’s appliance standards.

  • 2655.
    Zeng, Lei
    et al.
    CLASP China, Chaoyang, Beijing, China.
    Li, J.
    CLASP China, Chaoyang, Beijing, China.
    Yu, Y.
    CLASP China, Chaoyang, Beijing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Developing a products prioritization tool for energy efficiency standards improvements in China2014Inngår i: Energy Procedia, 2014, s. 2275-2279Konferansepaper (Fagfellevurdert)
    Abstract [en]

    China is the world's largest producer and consumer of household appliances, lighting and other residential and commercial equipment. Since 1989, China has developed and implemented over 40 energy efficiency (EE) standards and over 20 mandatory energy labels for a wide range of domestic, commercial and selected industrial equipment. However, there are tremendous opportunities to capture additional savings through more stringent energy efficiency policies for major energy-consuming appliances. To assess the stringency of EE standards, this paper developed an integrated products prioritization tool for energy efficiency standards improvements that comprises three component analyses: (1) analysis of market data, (2) quantification of energy savings potential, and (3) benchmarking China's EE standards to those of peer economies around the world. This integrated approach led to three independent but complementary studies, and an comprehensive analysis that resulted in a coherent set of policy recommendations on what products to prioritize for China's energy efficiency standards revisions, in order to maximize their energy savings.

  • 2656.
    Zetterholm, Emma
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Berglund, Jennifer
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    KOMMUNIKATIVT LEDARSKAP UR CHEFSPERSPEKTIV: En kvalitativ intervjustudie om chefers syn på ledarskap och kommunikation2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sammanfattning

    Frågaställning:

    • Vilka likheter och skillnader finns i chefernas ledarskap i vardagen jämfört med det teoretiska konceptet kommunikativt ledarskap?

     

    Syfte: Syftet är att få en fördjupad förståelse för hur det vardagliga ledarskapet i organisationen fungerar i förhållande till ett kommunikativt ledarskap.

     

    Metod: Teorin insamlades innan empirin, därefter har data samlats in utifrån en kvalitativ metod. Denna forskningsmetod valdes för att få en djupare förståelse i hur kommunikativa ledaregenskaper nyttjas inom en organisation. Att välja en kvalitativ metod kändes naturligt för oss då vi genom teorin kunde se att dialog mellan människor är viktigt för relationsskapande. Åtta semistrukturerade intervjuer utfördes med respondenter som har en chefsposition. Datan har sedan kategoriserats i olika teman som legat till grund för vårt resultat.

     

    Slutsats: Den slutsats som kan dras sett utifrån chefernas vardagskommunikation till sina medarbetare är att det finns både likheter och olikheter mellan chefernas ledarskap och det kommunikativa ledarskapet. De likheter som urskiljs i chefernas ledarskap är utan inbördes ordning: tydlighet, forma strukturer, hantera konflikter, närvaro, öppenhet, må bra själv som chef, kontinuerliga möten, skapa delaktighet kring mål samt låta medarbetarna vara delaktiga och ta egna beslut. Skillnaderna som uppmärksammats hos cheferna jämfört med det kommunikativa ledarskapet handlar om kopplingen till betydelsefullhet, feedback och återkoppling. Dessa upptäckter tyder på att alla de chefer som intervjuas utför ett mer eller mindre omedvetet kommunikativt ledarskap i sin vardagskommunikation med sina medarbetare.

     

  • 2657.
    Zetterlund, Frida
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Hammarlund Holmkvist, Viktor
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    80 % Administration, 20 % chef. - Ändå rätt nöjd?: En explorativ studie om sambandet mellan mängden administration och coachning och chefers arbetstillfredsställelse. Om förväntningar på chefers fördelning av arbetsuppgifter samt om utbildning och erfarenheter påverkar dessa förväntningar2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 2658.
    Zetterström, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Evaluation of a suction pyrometer: By heat and mass transfer methods2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sebastian Zetterström, Master of Science in energy systems, Mälardalens University in Västerås. Abstract of Master’s thesis, submitted 16th of August.

    Evaluation of a suction pyrometer by heat and mass transfer methods.

    The aim of the thesis is to evaluate the cooling of a specific suction pyrometer which is designed by Jan Skvaril, doctorate at Mälardalens University. First part is explained how the balances and correlations are performed before being implemented in MATLAB, after this  a ANSYS Fluent model is constructed and explained, which is used for the comparison of results.

    The cooling is performed by using water at an inlet temperature of 10°C and an assumed flue gas temperature of 810°C. Sensitivity analysis are performed to test the stability of the models which yield good results for stability, done by adjusting both flue gas temperature and inlet cooling water temperature which are as well presented for observation. From doing further MATLAB sensitivity analysis which show that the model still performs well and is stable.

    The resulting cooling water is heated to approximately 24, 8°C and the flue gas is cooled to 22, 4°C, in ANSYS Fluent the answer differs approximately 2°C and results in 20, 4°C which can be considered by looking at the flue gas inlet temperature of 810°C that this can be deemed an insignificant change and can therefore conclude that the comparison between the two platforms match each other good and that calculations can be considered accurate.

    Keywords:  Suction pyrometer, cooling, heat transfer, thermal resistance network, MATLAB, ANSYS Fluent, simulation

  • 2659.
    Zhang, C.
    et al.
    KTH, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Stockholm, Sweden.
    Liu, C.
    Swedish Road and Transport Research Institute, Stockholm, Sweden.
    Wang, K.
    Beijing Institute of Technology, Beijing, 100081, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Stockholm, Sweden.
    Crowdfunding preferences for a sustainable milk product with integrated photovoltaic water pumping system in China2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, artikkel-id 113694Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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. 

  • 2660.
    Zhang, C.
    et al.
    School of Chemical Science and Engineering, Royal Institute of Technology, 100 44, Stockholm Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Business, Society and Engineering, Mälardalen University, 721 23 Västerås, Sweden; School of Chemical Science and Engineering, Royal Institute of Technology, 100 44, Stockholm Sweden.
    Liu, C.
    Division of Traffic Analysis and Logistics, Swedish Road and Transport Research Institute, 100 44 Stockholm, Sweden.
    Wang, K.
    Center for Energy and Environmental Policy Research & School of Management and Economics, Beijing Institute of Technology, 100081 Beijing, China.
    Zhang, Y.
    School of Chemical Science and Engineering, Royal Institute of Technology, 100 44, Stockholm Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Business, Society and Engineering, Mälardalen University, 721 23 Västerås, Sweden; School of Chemical Science and Engineering, Royal Institute of Technology, 100 44, Stockholm Sweden.
    Purchase Intention for Crowd-funded Milk Products with Integrated Photovoltaic Water Pumping Systems in China2019Inngår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 159, s. 503-508Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In comparison with current financing mechanisms for renewable energy systems, crowd-funding financing mechanism offers a new potential source of financing with recent use of social media. Crowd-funding financing mechanism can also increases the social supports for renewable energy systems as users and investors turn to be more actively engaged in energy systems. As a new potential source of financing, crowd-funding mechanism has different forms, including donation, lending, equity and product reward approaches. In this paper, discrete choice model was used to explore whether crowd-funding financing with a novel sociotechnical product reward practice, has the attractions for potential customers to pay for a more sustainable milk product with distributed photovoltaic (PV) system. We empirically investigated the reward-base crowd funding with the specific integrated photovoltaic water pumping (PVWP) system in dairy milk production in China. 48 in-depth interviews were adopted for qualitative analysis of determinants of customer milk purchase decision. The ordered probit regression was employed with 357 online surveys to systematically estimate the purchase intention for the online-crowd-funding sustainable milk. Customer behaviours, environmental consciousness, and the individual socio-demographic factors were tested as potential explanatory variables. In the survey and depth interview samples, we found interviewees as potential customers showed strong purchase intentions to the crowd funding dairy milk for noticing milk quality and nutritious improvement, emission reduction and environmental benefits by the integrated PVWP system. In our findings of the regression results, the females, customers with young children or planning to have children were found with higher willing to purchase than other customers for crowd funding the sustainable dairy milk. The familiarity and popularity with online shopping and pre-sale purchase in China made customers more open and active towards pre-pay and crowd-funding mechanism.

  • 2661.
    Zhang, C.
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, J.
    Royal Institute of Technology, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Analysis of Distributed Photovoltaic Financing: A Case Study Approach of Crowd-funding with Photovoltaic Water Pumping System in Microgrids2016Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 103, s. 387-393Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Distributed photovoltaic (PV) system is playing an increasingly significant role in the fast growing global PV market, as a renewable power supply source. In rural and remote areas, the integrated PV technology with remote micro-grid offers a potential solution for agriculture and small businesses to access to clean, reliable and efficient energy source. As the cost of solar PV modules continues to show a downward tendency, the distributed PV systems with remote micro-grid are capable to meet growing energy demand with affordable price. Meanwhile, a series of policies and actions have been enacted in China since 2013, to motivate the distributed-generation PV development as equal as large-scale PV development. However, compared to coal-fired power plants or large-scale PV systems, a barrier exists in securing financing of distributed PV systems, which has high up-front costs and the risk of commercializing renewable energy initiatives. Under current market incentives and barriers, this paper studies the existing financing methods in distributed PV systems with remote distributed micro-grids. In comparison with other financing sources, a case study approach is employed with distributed PV water pumping system in China to introduce crowd-funding as a new source of financing in distributed PV systems. Through the SWOT analysis, this paper identifies a capacity for new financial approach of crowd-funding with PVWP deployment. The scenario is modelled for different stakeholders and organization forms that target social network interactions in crowd-funding, and the results provide insights for incentives and policy.

  • 2662.
    Zhang, C.
    et al.
    Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Yang, J.
    School of Humanities and Economic Management, China University of Geosciences, Beijing, China.
    Yu, C.
    Department of Earth System Science, Tsinghua University, Beijing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Economic assessment of photovoltaic water pumping integration with dairy milk production2018Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 177, s. 750-764Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As dairy consumption grows, domestic dairy farms face challenges in reducing the cost of feeds and the production of high-quality milk for market demands. This paper aims to introduce and integrate solar energy into the milk production chain to investigate its economic performance. By collecting data on milk production processes from 11 dairy farms in China, we quantified electricity usage and costs of milk production to identify the best and worst cases. Crop yields response to the water demand and the electricity requirements of the dairy farms were considered. The study simulated scenarios of self-sufficiency at 20%, 80%, and 100%, in the identified farms by integrating a photovoltaic water pumping (PVWP) system to provide both power and water for alfalfa and other feeds’ irrigation and subsequent milk production. We evaluated annual discounted cost, revenue and net profit under each scenario and case. The results showed that a dairy farm with an integrated PVWP system and self-sufficient feeds would lead to value add-ins, such as electricity saving with solar energy generation, economic cost saving of crops, and CO2 emission reduction. The analysis on return on investment (ROI) and internal rate of return (IRR) revealed that not all the self-sufficient feeds can bring positive marginal profit. Among the investigated scenarios and cases, the dairy farm marked out by the highest ROI with 3.12 and IRR with 20.4%, was the farm where the integrated PVWP system was used to reach 20% self-sufficiency (self-production of only alfalfa). The other scenarios and cases with higher levels of self-sufficiency showed lower ROIs and IRRs. This indicates that high self-production levels of feeds decrease the total profit due to high investment cost. Sensitivity analyses of crop price and operational cost were conducted for ROI with single and double factor approaches. Scale and production of feeds proportions should be carefully considered in improving the economic performance of dairy milk production.

  • 2663.
    Zhang, C.
    et al.
    Royal Institute of Technology, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, J.
    Royal Institute of Technology, Sweden.
    Zhang, J.
    China Petroleum Daily, Jia NO.3, AnHuali 2, ChaoYang District, Beijing, China Petroleum Daily, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Sweden.
    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 China2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 3953-3959Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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. 

  • 2664.
    Zhang, C.
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    CDM's influence on technology transfers: A study of the implemented clean development mechanism projects in China2015Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 158, nr 15, s. 355-365Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Technology transfers through the Clean Development Mechanism (CDM) under the Kyoto Protocol is one of the most important catalysts in the cooperation between developed (Annex I) and developing (non-Annex I) countries for climate change mitigation. With the large-scale implementation of CDM projects in recent years, it is important to timely and comprehensively analyze the effectiveness of technology transfers in these implemented projects on the level of individual countries. In this context, China is of particular significance as it is the biggest host country of CDM projects in the world; 50% of total CDM projects implemented from 2007 to 2012 have issued Certified Emission Reductions (CERs) to 60% of all of the CDM projects. In this study, we evaluated the performance of technology transfers in an exclusive database of 754 CDM projects hosted by China between 2007 and 2012 with issued CERs since CERs were first issued in China. In addition, we developed a logistic regression approach using 11-variables that include a series of extended technology transfer-based indicators from the perspectives of project design, economic level, and technology capability that have not been studied in detail in the past. The results show that technology transfers are more likely to occur in large-sized projects with higher CER incomes, in projects with international participants, and in projects involving types such as HFC-23 reduction, fuel substitute, and N<inf>2</inf>O decomposition, in comparison to projects involving renewable energy. We observed that over 90% of the technology transfer projects only include importation of equipment or training to China. In our findings of the regression results, it shows that technology transfers occurred more often in regions with lower technology capabilities, less energy consumption, and a lower GDP growth rate. Supported by high local technology capability and the governmental strategy with independent innovation, the advantages of introducing technology from other countries are offset by local technology diffusion. In a market view, financial incentives hinder CDM host parties from introducing new equipment or trainings for the high marginal cost, unless the high marginal cost of technology transfer can be offset by a large CDM with a high CER income. Technology transfer is more income-driven than sustainability-driven at the present stage in China. In our analysis, the drive out effect between HFC-23 and renewable projects in CDM suggests China government to publish more effective incentives to attract more sustainable types of CDM projects with a higher level of technology innovation. The results are also discussed in the context of policy issues, which can be helpful for the decision makers when formulating future sustainable strategic plans and policy. 

  • 2665. Zhang, Chi
    et al.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Liu, C.
    Zhang, Yang
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Sweden.
    Wang, K.
    Choice Preferences And Willingness‐To‐Pay For Crowd‐Funding With Integrated Photovoltaic Water Pumping System In Dairy Milk Production In China2018Konferansepaper (Fagfellevurdert)
  • 2666.
    Zhang, Chi
    et al.
    School of Chemical Science and Engineering, Royal Institute of Technology.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, Jan
    School of Chemical Science and Engineering, Royal Institute of Technology.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Economic performance of photovoltaic water pumping systems with business model innovation in China2017Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 33, nr 1, s. 498-510Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Expansion by photovoltaic (PV) technologies in the renewable energy market requires exploring added value integrated with business model innovation. In recent years, a pilot trial of PV water pumping (PVWP) technologies for the conservation of grassland and farmland has been conducted in China. In this paper, we studied the added value of the PVWP technologies with an emphasis on the integration of the value proposition with the operation system and customer segmentation. Using the widely used existing PV business models (PV-roof) as a reference, we evaluated discounted cash flow (DCF) and net present value (NPV) under the scenarios of traditional PV roof, PVWP pilot, PVWP scale-up, and PVWP social network, where further added value via social network was included in the business model. The results show that the integrated PVWP system with social network products significantly improves the performance in areas such as the discounted payback period, internal rate of return (IRR), and return on investment (ROI). We conclude that scenario PVWP social network with business model innovation, can result in value add-ins, new sources of revenue, and market incentives. The paper also suggests that current policy incentives for PV industry are not efficient due to a limited source of revenue, and complex procedures of feed-in tariff verification.

  • 2667.
    Zhang, H.
    et al.
    University of Waterloo, Canada.
    Li, X.
    University of Waterloo, Canada.
    Liu, X.
    University of Waterloo, Canada.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Enhancing fuel cell durability for fuel cell plug-in hybrid electric vehicles through strategic power management2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 241, s. 483-490Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fuel cell plug-in hybrid electric vehicles (FC-PHEVs) can have extended range while utilizing cheap grid electricity, but has poor durability of onboard fuel cells due to dynamic loading. In this study, fuel cell durability is enhanced significantly for a novel configuration of FC-PHEVs with three fuel cell stacks through strategic power management by making each fuel cell stack work only at a fixed operating point (i.e., constant output power) and by shortening its active time (operation) via on-off switching control. A hysteresis control strategy of power management is designed to make the active time evenly distributed over the three fuel cell stacks and to reduce the number of on-off switching. The results indicate that the durability of the onboard fuel cells can be increased 11.8, 4.8 and 6.9 times, respectively, for an urban, highway and a combined urban-highway driving cycle. This enhanced fuel cell durability is derived from the fact that the average power demand of real-time driving cycles is only a fraction of the maximum power that FC-PHEVs could provide, and substantially increased durability can be used to reduce the over-design, hence the cost, of fuel cells. 

  • 2668.
    Zhang, J.
    et al.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Liu, J.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhang, R.
    Institute of Water Resources for Pastoral Areas, Hohhot, China .
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Gao, X.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Model of evapotranspiration and groundwater level based on photovoltaic water pumping system2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, s. 1132-1137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) water pumping system has been proved being environmental-friendly and low energy-cost, which has a promising prospect in arid areas which are rich in solar energy resources. However, water resources remain to be one of the main restraints to the application of PV water pumping system widely. Models to evaluate the evapotranspiration and groundwater level in the well are estimated based on the data of a field trip, which was conducted in Wulanchabu grassland, Inner Mongolia, China. Data about the performance of the PV water pumping system, including evapotranspiration and the groundwater level variation were collected. In this paper, evapotranspiration is calculated by Penman-Monteith method and Theis formula is introduced to calculate the soil characters and simulate the groundwater level variation. PRMSE and Nash-Sutcliffe efficiency are used to validate the model performance with the collected lysimeter data and groundwater level. The results show that the modeling of the evapotranspiration and groundwater level is reliable. According to the water demand and energy demand, the method to optimize the pumping system is introduced. Based on the calculated result and collected data of water demand and groundwater level, groundwater in the site is abundant to support the system. However, due to the stickiness of the soil condition, the recharge rate is smaller than the pumping rate. According to the comparison, the current system is oversized. In this condition, the pump would run out of water, and have to stop pumping. Therefore, not only the water quantity is an important factor to be considered, the soil condition and recharge rate are also of great significance to the optimization of photovoltaic water pumping systems.

  • 2669.
    Zhang, Jie
    et al.
    Univ Maryland, USA..
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yao, Tian
    Univ Space Res Assoc, Columbia, USA..
    Zhang, Yang
    KTH Royal Inst Technol, Stockholm, Sweden..
    Lundblad, Anders
    Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden.;KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Melton, Forrest
    NASA ARC CREST, Calif State Univ Monterey Bay, USA..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Stockholm, Sweden..
    The water-food-energy nexus optimization approach to combat agricultural drought: a case study in the United States2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, s. 449-464Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The frequent recent drought events in the Great Plains of United States have led to significant crop yield reductions and crop price surges. Using an integrated water-food-energy nexus modelling and optimization approach, this study laid the basis for developing an effective agricultural drought management system by combining real-time drought monitoring with real-time irrigation management. The proposed water-food-energy simulation and optimization method is spatially explicit and was applied to one major corn region in Nebraska. The crop simulations, validated with yield statistics, showed that a drought year like 2012 can potentially reduce the corn yield by 50% as compared to a wet year like 2009. The simulation results show that irrigation can play a key role in halting crop losses due to drought and in sustaining high yields of up to 20 t/ha. Nevertheless, the water-food-energy relationship shows that significant investments on water and energy are required to limit the negative effects of drought. The multi-criteria optimization problem developed in this study shows that the optimal crop yield does not necessarily correspond to the maximum yield, resulting in potential water and energy savings. (C) 2017 Elsevier Ltd. All rights reserved.

  • 2670.
    Zhang, Q.
    et al.
    Academy of China Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing, China.
    Li, Y.
    Academy of China Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wang, G.
    Academy of China Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing, China.
    Chen, S.
    Academy of China Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing, China.
    Study on the Impacts of the LNG Market Reform in China using a SVM based Rolling Horizon Stochastic Game Analysis2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 3850-3855Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Natural gas is expected to play a much more important role in China in future decades and its market reform is crucial for its fast market penetration. At present, the main gas fields, pipeline and Liquefied Natural Gas (LNG) infrastructure are monopolized by the state owned big companies, and one of the important market reform policies is to open the LNG import rights to small private companies or traders. Therefore, in the present study, a Game Analysis Model is proposed to analyze and compare the impacts of different market structures on infrastructure deployment and social welfare. Moreover, a Support Vector Machine (SVM) based rolling horizon stochastic method has been adopted in the model to simulate the real LNG price fluctuations. The results indicate that, with the third part access (TPA) entrance into LNG market, the construction of LNG infrastructure will be promoted and more gas will be provided with lower prices, and thus the total social welfare will be improved greatly. 

  • 2671.
    Zhang, Q.
    et al.
    China University of Petroleum-Beijing, Beijing, China .
    Mclellan, B. C.
    Kyoto University, Kyoto, Japan.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An integrated scenario analysis for future zero-carbon energy system2015Inngår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 39, nr 7, s. 993-1010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An integrated scenario analysis methodology has been proposed for zero-carbon energy system in perspectives of social-economy, environment and technology. By using the methodology, service demands in all sectors were estimated based on social-economic data, and then the best technology and energy mixes were obtained to meet the service demands. The methodology was applied to Japan toward zero-carbon energy system out to the year of 2100, and three different scenarios of nuclear power development are considered in light of the Fukushima accident: (i) no further introduction of nuclear, (ii) fixed portion and (iii) no limit of nuclear. The results show that, zero-carbon energy scenario can be attained in the year 2100 when electricity will supply 75% of total energy consumption, and three power generation scenarios were proposed, 30% renewable and 70% gas-carbon capture and storage (CCS) in Scenario 1, respective one-third nuclear, renewable and gas-CCS in Scenario 2, and 60% nuclear power, 20% renewable and 10% gas-CCS in Scenario 3. Finally, Scenario 2 is rated as the most balanced scenario by putting emphasis on the availability of diversified power source, considering the inter-comparison of the three scenarios from the four aspects of cost, CO<inf>2</inf> emission, risk and diversity. 

  • 2672.
    Zhang, Qi
    et al.
    China Univ Petr, Acad Chinese Energy Strategy, Beijing 102249, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mclellan, Benjamin
    Kyoto Univ, Grad Sch Energy Sci, Kyoto 6068501, Japan..
    An Integrated Scenario Analysis for Future Zero-Carbon Energy System2014Inngår i: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J Lee, DJ Chou, SK Desideri, U Li, H, ELSEVIER SCIENCE BV , 2014, s. 2801-2804Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An integrated scenario analysis methodology has been proposed for zero-carbon energy system in perspectives of social-economy, environment and technology. In the methodology, firstly various service demands were estimated based on social-economic data, and best technology and energy mixes were obtained using the optimization model to meet the service demand. The methodology has been applied to Japan toward zero-carbon energy system out to 2100. The results show that, in the end user side, zero-carbon energy scenario was obtained based on 75% on electricity and three power generation scenarios were proposed, 30% renewable and 70% gas-CCS in scenario 1, respective one third nuclear, renewable and gas-CCS in scenario 2, and 60% nuclear power, 20% renewable and 10% gas-CCS in scenario 3. Finally, the scenario 2 with balanced diversity in nuclear, renewable and gas-CCS was recommended based on comprehensive inter-comparisons. The feasibility of the proposed methodology has been demonstrated. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  • 2673.
    Zhang, Qi
    et al.
    China University of Petroleum.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhu, Lijing
    China University of Petroleum.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lu, Huihui
    China University of Petroleum.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sun, Qie
    Shandong University.
    Factors influencing the economics of public charging infrastructures for EV: A review2018Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 97, s. 500-509Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Growing concerns about energy conservation and the environmental impacts of greenhouse gas emissions over the world have promoted the development of the electric vehicles (EVs) market. However, one of the biggest barriers in the development of the EV market is the lack of the public charging infrastructure. This paper reviews the factors that can directly and indirectly influence the economics of the public charging infrastructure. The knowledge gaps, barriers and opportunities in the development of the charging infrastructure have been identified and analyzed. In order to promote the development of the public charging infrastructure, more research efforts should be paid on the impacts of psychological factors of customers and the technical development of charging infrastructures and EV batteries. The government support has been proved to play an important role, so that how the government policy can be tailored for the development of the charging infrastructure market should receive more attentions. In addition, the charging price as an endogenous factor should be considered more carefully in modelling the charging infrastructure market. New business models are also urgently needed to accelerate the future development of the public charging infrastructure.

  • 2674.
    Zhang, Qi
    et al.
    China University of Petroleum, China.
    Li, Zhang
    China University of Petroleum, China.
    Wang, Ge
    China University of Petroleum, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Study on the impacts of natural gas supply cost on gas flow and infrastructure deployment in China2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, s. 1385-1398Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impacts of gas supply costs on interregional gas flow and gas infrastructure deployment in China are analyzed out to 2035 by using an optimization model in the present study. There two options for gas supply includes successive two-step procedures of imports or domestic productions and transportation by using infrastructures within China. Four possible supply cost scenarios are proposed considering the uncertainties of import price, domestic unconventional gas production cost and geopolitical turbulence in import source countries. The analysis results show that (1). Domestic unconventional gas production cost (wellhead price) and gas import cost (import gas price represented by CIF) are two key points to gas flow and infrastructure deployment in China; (2). The development of unconventional gas is conductive to supply cost reduction and maintenance of infrastructure deployment stability, especially to Southwest and North China regions; (3). When gas import price increases, LNG import will decrease more than pipeline import, and imported LNG will be partly replaced by pipeline import rather than domestic gas in coastal regions; (4). The disruption of gassupply from Myanmar will lead to great changes of gas flow and infrastructure deployment in Southwest China regions; (5). The infrastructures are deployed according to the optimization gas flow in different scenarios.

  • 2675.
    Zhang, X.
    et al.
    ABB AB, Corporate Research, Vasteras, Sweden.
    Yan, J.
    Vattenfall AB, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Chekani, S.
    Royal Institute of Technology, Stockholm, Sweden .
    Liu, L.
    Royal Institute of Technology, Stockholm, Sweden .
    Energy saving for biogas production and upgrading - Thermal integration2014Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, s. 121-125Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal integration of anaerobic digestion (AD) biogas production with amine based biogas upgrading has been studied for improving the overall thermal efficiencies of the two systems. The thermal characteristics have been investigated for typical AD raw biogas generation and MEA absorption biogas upgrading. The investigation provides a basic understanding of energy saving for both industrial scale biogas production and upgrading processes. The thermal integration is carried out based on the thermal characteristics of the two systems by well-defined case studies, which take the following factors into account such as important thermal conditions of sub-systems, material and energy balances, the efficiencies of heat exchange and heat transfer, necessary integration optimization and ambient conditions. The results show that the thermal integration is achievable with very positive effects for overall energy efficiency and water usage.

  • 2676.
    Zhang, Xiaojing
    et al.
    ABB AB, Corp Res, Västerås, Sweden.
    Yan, Jinying
    Vattenfall AB, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Chekani, Shabnam
    Royal Inst Technol,Stockholm, Sweden.
    Liu, Loncheng
    Royal Inst Technol,Stockholm, Sweden.
    Investigation of thermal integration between biogas production and upgrading2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 131-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal integration of anaerobic digestion (AD) biogas production with amine-based chemical absorption biogas upgrading has been studied to improve the overall efficiency of the intergraded system. The thermal characteristics have been investigated for industrial AD raw biogas production and amine-based chemical absorption biogas upgrading. The investigation provides a basic understanding for the possibilities of energy saving through thermal integration. The thermal integration is carried out through well-defined cases based on the thermal characteristics of the biogas production and the biogas upgrading. The following factors are taken into account in the case study: thermal conditions of sub-systems, material and energy balances, cost issues and main benefits. The potential of heat recovery has been evaluated to utilise the waste heat from amine-based upgrading process for the use in the AD biogas production. The results show that the thermal integration has positive effects on improving the overall energy efficiency of the integrated biogas plant. Cost analysis shows that the thermal integration is economically feasible. 

  • 2677.
    Zhang, X.X.
    et al.
    Beijing Forestry University, China.
    Liu, J.G.
    South University of Science & Technology of China (SUSTC), China.
    Tang, Y.
    South University of Science & Technology of China, China.
    Zhao, X.
    Hohai University, China.
    Yang, H.
    University of Basel, Suisse.
    Gerbens-Leenes, P.W.
    University of Groningen, Netherlands.
    Van Vliet, M.T.H
    Wageningen University & Research, Netherlands.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    China's coal-fired power plants impose pressure on water resources2017Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 161, s. 1171-1179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Coal is the dominant fuel for electricity generation around the world. This type of electricity generation uses large amounts of water, increasing pressure on water resources. This calls for an in-depth investigation in the water-energy nexus of coal-fired electricity generation. In China, coal-fired power plants play an important role in the energy supply. Here we assessed water consumption of coal-fired power plants (CPPs) in China using four cooling technologies: closed-cycle cooling, once-through cooling, air cooling, and seawater cooling. The results show that water consumption of CPPs was 3.5 km(3), accounting for 11% of total industrial water consumption in China. Eighty-four percent of this water consumption was from plants with closed-cycle cooling. China's average water intensity of CPPs was 1.15 l/kWh, while the intensity for closed-cycle cooling was 3-10 times higher than that for other cooling technologies. About 75% of water consumption of CPPs was from regions with absolute or chronic water scarcity. The results imply that the development of CPPs needs to explicitly consider their impacts on regional water resources. 

  • 2678.
    Zhang, Y.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lundblad, A.
    KTH Royal Institute of Technology, Sweden.
    Wang, L.
    Chongqing University, Chongqing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Swed.
    The Influence of Photovoltaic Models and Battery Models in System Simulation and Optimization2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 1184-1191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Selecting accurate and robust models is important for simulation and optimization of a clean energy system. This paper compares two photovoltaic (PV) models and two battery models in an open-source code, Opti-CE. The PV models are single diode model and its simplified model. The battery models are Improved Shepherd model and energy balance model. The models are compared from a perspective of overall system simulation and optimization in particular on both accuracy and computational time. The results indicate that simplified PV model causes 0.86% normalized root mean square error (nRMSE) compared with the single diode model, while decreases the simulation time from more than 800s to less than 0.01s. The energy balance battery model reduces simulation time from more than 5s to less than 0.03s. The energy balance model tends to underestimate the battery State of Charge (SOC) compared with the Improved Shepherd model. However, the error is not accumulative during the simulation. Compared to the Pareto front with single diode model and Improved Shepherd model, the simplified PV model increases the Pareto front values and result in both higher Self Sufficiency Ratio (SSR) and Net Present Value (NPV), while the energy balance battery model decreases the part of Pareto front, where individuals have low NPV. 

  • 2679.
    Zhang, Y.
    et al.
    KTH-Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH-Royal Institute of Technology, Stockholm, Sweden.
    Yang, Ying
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Stridh, Bengt
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lundblad, A.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. RISE Research Institutes of Sweden, Borås, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH-Royal Institute of Technology, Stockholm, Sweden.
    Energy flexibility from the consumer: Integrating local electricity and heat supplies in a building2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 223, s. 430-442Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing penetration level of renewable energy requires more flexibility measures to be implemented in future energy systems. Integrating an energy consumer’s local energy supplies connects multiple energy networks (i.e., the electrical grid, the district heating network, and gas network) in a decentralized way. Such integration enhances the flexibility of energy systems. In this work, a Swedish office building is investigated as a case study. Different components, including heat pump, electrical heater, battery and hot water storage tank are integrated into the electricity and heat supply system of the building. Special focus is placed on the flexibility that the studied building can provide to the electrical grid (i.e., the building modulates the electricity consumption in response to the grid operator’s requirements). The flexibility is described by two metrics including the flexibility hours and the flexibility energy. Optimization of the component capacities and the operation profiles is carried out by using Mixed Integer Linear Programming (MILP). The results show that the system fully relies on electricity for the heat demand when not considering the flexibility requirements of the electrical grid. This suggests that district heating is economically unfavorable compared with using electricity for the heat demand in the studied case. However, when flexibility requirements are added, the system turns to the district heating network for part of the heat demand. The system provides great flexibility to the electrical grid through such integration. The flexibility hours can be over 5200 h in a year, and the flexibility energy reaches more than 15.7 MWh (36% of the yearly electricity consumption). The yearly operation cost of the system slightly increases from 62,273 to 65,178 SEK when the flexibility hours increase from 304 to 5209 h. The results revealed that flexibility can be provided from the district heating network to the electrical grid via the building.

  • 2680.
    Zhang, Y.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Lundblad, A.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Comparative Study of Battery Storage and Hydrogen Storage to Increase Photovoltaic Self-sufficiency in a Residential Building of Sweden2016Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 103, s. 268-273Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) is promising to supply power for residential buildings. Battery is the most widely employed storage method to mitigate the intermittence of PV and to overcome the mismatch between production and load. Hydrogen storage is another promising method that it is suitable for long-term storage. This study focuses on the comparison of self-sufficiency ratio and cost performance between battery storage and hydrogen storage for a residential building in Sweden. The results show that battery storage is superior to the hydrogen storage in the studied case. Sensitivity study of the component cost within the hydrogen storage system is also carried out. Electrolyzer cost is the most sensitive factor for improving system performance. A hybrid battery and hydrogen storage system, which can harness the advantages of both battery and hydrogen storages, is proposed in the last place.

  • 2681.
    Zhang, Y.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Lundblad, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Benavente, F.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Battery sizing and rule-based operation of grid-connected photovoltaic-battery system: A case study in Sweden2017Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 133, s. 249-263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The optimal components design for grid-connected photovoltaic-battery systems should be determined with consideration of system operation. This study proposes a method to simultaneously optimize the battery capacity and rule-based operation strategy. The investigated photovoltaic-battery system is modeled using single diode photovoltaic model and Improved Shepherd battery model. Three rule-based operation strategies—including the conventional operation strategy, the dynamic price load shifting strategy, and the hybrid operation strategy—are designed and evaluated. The rule-based operation strategies introduce different operation parameters to run the system operation. multi-objective Genetic Algorithm is employed to optimize the decisional variables, including battery capacity and operation parameters, towards maximizing the system's Self Sufficiency Ratio and Net Present Value. The results indicate that employing battery with the conventional operation strategy is not profitable, although it increases Self Sufficiency Ratio. The dynamic price load shifting strategy has similar performance with the conventional operation strategy because the electricity price variation is not large enough. The proposed hybrid operation strategy outperforms other investigated strategies. When the battery capacity is lower than 72 kW h, Self Sufficiency Ratio and Net Present Value increase simultaneously with the battery capacity.

  • 2682.
    Zhang, Y.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Lundblad, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Employing battery storage to increase photovoltaic self-sufficiency in a residential building of Sweden2016Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 88, s. 455-461Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) or hybrid PV-battery systems are promising to supply power for residential buildings. In this study, the load profile of a multi apartment building in Gothenburg and the PV production profile under local weather conditions are compared and analyzed. Three different types of batteries, including lead acid, NaNiCl (Sodium-Nickel-Chloride) and Lithium ion, are studied in combination with the PV systems. It is found that Lithium ion battery system is superior in achieving higher Self-Sufficiency Ratio (SSR) with the same Life Cycle Cost (LCC). Achieving high SSR with the hybrid PV-battery system is unrealistic because of the seasonal mismatch between the load and electricity production profile. The capacity match between the PV and battery to maximize SSR was investigated, showing different trends under system LCC range of 0.1-40 Million SEK (1SEK≈0.12USD). The system LCC should be lower than 10.6 Million SEK (at the SSR of 36%) in order to keep the payback time positive. 

  • 2683.
    Zhang, Yang
    et al.
    KTH Royal Inst Technol, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Anders, Lundblad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Sweden.
    Comparative study of hydrogen storage and battery storage in grid connected photovoltaic system: Storage sizing and rule-based operation2017Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 201, s. 397-411Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper studies grid-connected photovoltaic (PV)-hydrogen/battery systems. The storage component capacities and the rule-based operation strategy parameters are simultaneously optimized by the Genetic Algorithm. Three operation strategies for the hydrogen storage, namely conventional operation strategy, peak shaving strategy and hybrid operation strategy, are compared under two scenarios based on the pessimistic and optimistic costs. The results indicate that the hybrid operation strategy, which combines the conventional operation strategy and the peak shaving strategy, is advantageous in achieving higher Net Present Value (NPV) and Self Sufficiency Ratio (SSR). Hydrogen storage is further compared with battery storage. Under the pessimistic cost scenario, hydrogen storage results in poorer performance in both SSR and NPV. While under the optimistic cost scenario, hydrogen storage achieves higher NPV. Moreover, when taking into account the grid power fluctuation, hydrogen storage achieves better performance in all three optimization objectives, which are NPV, SSR and GI (Grid Indicator). 

  • 2684. Zhang, Yang
    et al.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Anders, Lundblad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhang, Chi
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Sweden.
    Building Energy System: From System Planning To Operation2018Konferansepaper (Fagfellevurdert)
  • 2685.
    Zhang, Yang
    et al.
    KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden..
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden.; Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Lundblad, Anders
    RISE Res Inst Sweden, Div Safety & Transport Elect, SE-50462 Boras, Sweden..
    Zheng, Wandong
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden.; Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Planning and operation of an integrated energy system in a Swedish building2019Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 199, artikkel-id 111920Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    More flexibility measures are required due to the increasing capacities of variable renewable energies (VRE). In buildings, the integration of energy supplies forms integrated energy systems (IES). IESs can provide flexibility and increase the VRE penetration level. To upgrade a current building energy system into an IES, several energy conversion and storage components are needed. How to decide the component capacities and operate the IES were investigated separately in studies on system planning and system operation. However, a research gap exists that the system configuration from system planning is not validated by actual operation conditions in system operation. Meanwhile, studies on system operation assume that IES configurations are predetermined. This work combines system planning and system operation. The IES configuration is determined by mixed integer linear programming in system planning. Actual operation conditions and forecast errors are considered in system operation. The actual operation profiles are obtained through year-round simulations of different energy management systems. The results indicate that the system configuration from system planning can meet energy demands in system operation. Among different energy management systems, the combination of robust optimization and receding horizon optimization achieves the lowest yearly operation cost. Meanwhile, two scenarios that represent high and low forecast accuracies are studied. Under the high and low forecast accuracy scenarios, the yearly operation costs are about 4% and 6% higher than that obtained from system planning.

  • 2686.
    Zhang, Yang
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, Ying
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lundblad, Anders
    Division Safety and Transport/Electronics, RISE Research Institutes of Sweden, SE-50462 Borås, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Energy Flexibility through the Integrated Energy Supply System in Buildings: A Case Study in Sweden2018Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 145, s. 564-569Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing penetration level of renewable energies requires more flexibility measures at the consumption side. Flexible energy prices have been placed by energy providers to promote flexibility measures from energy users. However, because of the current energy supply system in buildings, these flexible energy prices haven’t been fully taken advantage of. This study focuses on the integrated energy supply system in buildings. A Swedish office building is used as the case study. The integrated energy supply system is built by installing new components, including battery, heat pump and electrical heater, and hot water tank. Mixed Integer Linear Programming (MILP) problems are solved to determine the optimal component capacities and operation profiles. The results indicate that all the studied system configurations achieve lower net present cost (NPC) than the current system. It suggests that the integrated energy supply system can take advantage of the flexible energy prices and lower the overall energy cost in the building. Among the studied configurations, the combination of air source heat pump (ASHP) and electrical heater (EH) has the lowest investment cost. This combination also has the lowest NPC except in the scenario with low borehole cost.

  • 2687.
    Zhanga, C.
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Business model innovation on the photovoltaic water pumping systems for grassland and farmland conservation in China2014Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, s. 1483-1486Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Penetration of the renewable market of Photovoltaic PV technologies calls for the extension of the additional values generated from the technology including climate and social co-benefits as radical innovations in a new business model. Compared with existing PV business models, this paper extends the value proposition into operation system and customer segmentation, investigated by a pilot demonstration of PV water pumping (PVWP) systems for the conservation of grassland and farmland in China. The paper suggests that the integrated PVWP systems can combine the implementation of technology with environmental co-benefits, agricultural products by developing an interactive interface to link a social network. This can further disseminate benefits to stimulate the active participations of investments from individuals and corporations. Discounted cash flow (DCF) model and net present value (NPV) evaluations have been conducted on the traditional PV roof, PVWP pilot and PVWP scale up scenarios. The results show that the scenario of integrated PVWP system with social network products can significantly improve the payback period (PP) and increase internal rate of return (IRR). Based on the PVWP pilots and relevant industrial environments, the results in this paper provide how the innovative PV business model innovation can improve the present practices and policies on PV technologies implementation.

  • 2688.
    Zhao, R.
    et al.
    Ministry of Education of China, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Wang, S.
    Tianjin University, Tianjin, China.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Zhang, Y.
    Ministry of Education of China, Tianjin, China.
    Liu, B.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    Thermodynamic research of adsorbent materials on energy efficiency of vacuum-pressure swing adsorption cycle for CO2 capture2018Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 128, s. 818-829Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a comprehensive thermodynamic research on energy efficiency of vacuum-pressure swing adsorption (VPSA). The study examined the influence from four types of typical adsorbent materials on the energy efficiency of VPSA by cycle parameters. The selected adsorbent materials are activated carbons, zeolite 5A, zeolite 13X, silica gels, and metal-organic frameworks (MOFs). The study also analyzes the effects of separation temperature, adsorption pressure, desorption pressure, CO2 concentration and percent of unused bed on the energy-efficiency of VPSA cycle. The examined performance parameters are CO2 working capacity, proportionality factor, energy consumption and second-law efficiency. The results show that the energy consumption is approximately 2.0–4.5 MJ/kg and the second-law efficiencies are 4–7% for VPSA cycles using the five adsorbent materials. The effect of adsorbent materials on the energy efficiency mainly depends on the proportionality factor of CO2 working capacity (β) of VPSA cycle, which is important to screen materials at the fixed cyclic boundary conditions and preliminary calculation of second-law efficiency for VPSA cycles. For existing adsorbent materials which are Type I commonly, the lower values of β would lead to the higher second-law efficiencies. The development of new adsorbents of Type III would be extremely urgent in near future. 

  • 2689.
    Zhao, R.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Liu, L.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thermodynamic analysis on carbon dioxide capture by Electric Swing Adsorption (ESA) technology2018Inngår i: Journal of CO2 Utilization, ISSN 2212-9820, E-ISSN 2212-9839, Vol. 26, s. 388-396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study explores the impacts of materials, such as adsorbents and electrodes, on the energy efficiency of a 4-step ESA cycle for CO2 capture. Three types of adsorbents including activated carbon honeycomb monolith (ACHM) and two hybrid adsorbents are compared, and two kinds of electrodes such as aluminum and brass are combined for comparative analysis. Process description of ESA cycle, including feed, electrification, electrification with purge and cooling, is presented via the adsorption isotherm diagram. By the theory of thermodynamic carbon pump, sensitivity analysis of cycle parameters is evaluated in terms of the second-law efficiency (Eff2nd) and the electrical heating efficiency (Effele). The results show that Eff2nd of the employed adsorbents is in the range of 1.17%-6.15%, and Effele of the selected electrodes is between 27.46% and 60.91%. Among the three adsorbents, Eff2nd of ACHM is the lowest one compared to the others. Similarly, Effele of the combination with brass is superior to that of the groups with aluminum. However, the actual efficiency of ESA cycle is the production of both Eff2nd and Effele, which is approximately 1.03%-3.66%. Typical measures are proposed to reduce the heat loss of the adsorbents and electrodes as well for future work. 

  • 2690.
    Zhao, R.
    et al.
    Royal Institute of Technology, Sweden.
    Liu, L.
    Royal Institute of Technology, Sweden.
    Zhao, L.
    Tianjin University, Ministry of Education, China.
    Deng, S.
    Tianjin University, Ministry of Education, China.
    Li, S.
    Tianjin University, Ministry of Education, China.
    Zhang, Y.
    Tianjin University, Ministry of Education, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Techno-economic analysis of carbon capture from a coal-fired power plant integrating solar-assisted pressure-temperature swing adsorption (PTSA)2019Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 214, s. 440-451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a techno-economic study to seek the feasibility about the proposed system that integrating solar-assisted pressure-temperature swing adsorption (PTSA) into an 800MWe coal-fired power plant. Solar energy has the potential to supply thermal energy demand for carbon capture, which can avoid the energy consumption of the traditional method such as the steam extraction. The performance of the proposed system is largely affected by the climatic conditions and solar collector's types. The assessment criteria include carbon emission intensity (CEI), levelized cost of electricity (LCOE) and cost of CO2 avoidance (COA). By the parametric analysis, the results show that CEI of the novel system with solar thermal collectors is approximately 2g/kWh lower than that of the referenced power plant with CO2 adsorption capture. In addition, CEI of the novel system can be further decrease with the decline of desorption temperature, adsorption pressure and desorption pressure. For the sake of lower LCOE and COA, the prices of the power plant capacity, adsorbents and solar collectors should be reduced. Specifically, LCOE of the system with evacuated tube collector will be lower than that of the reference system with CO2 capture as the price of solar field is lower than 46.08 USD/m2.

  • 2691.
    Zhao, R.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Liu, L.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Li, S.
    Ministry of Education of China, Tianjin, China.
    Zhang, Y.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thermodynamic exploration of temperature vacuum swing adsorption for direct air capture of carbon dioxide in buildings2019Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 183, s. 418-426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abrupt climate change such as the loss of Arctic sea-ice area urgently needs negative emissions technologies. The potential application of direct air capture of carbon dioxide from indoor air and outdoor air in closed buildings or crowded places has been discussed in this paper. From the aspects of carbon reduction and indoor comfort, the ventilation system integrating a capture device is of great value in practical use. For ultra-dilute carbon dioxide sources, many traditional separation processes have no cost advantages, but adsorption technologies such as temperature vacuum swing adsorption is one of suitable methods. Thermodynamic exploration has been investigated regarding minimum separation work and second-law efficiency at various concentrations in the air. The influence of concentration, adsorption temperature, desorption temperature and desorption pressure on the energy efficiency has also been evaluated. Results show that the minimum separation work for the level of 400 ppm is approximately 20 kJ/mol. The optimal second-law efficiencies are 44.57%, 37.55% and 31.60%, respectively for 3000 ppm, 2000 ppm and 1000 ppm. It means that a high energy-efficiency capture device in buildings merits attention in the exploration of the possibility of approaching negative carbon buildings. 

  • 2692.
    Zhao, R.
    et al.
    Ministry of Education of China, Tianjin, China.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Wang, S.
    Tianjin University, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    Solar-assisted pressure-temperature swing adsorption for CO2 capture: Effect of adsorbent materials2018Inngår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 185, s. 494-504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Because of the ability to utilize the low-grade solar thermal energy for regeneration, a CO2 capture system characterized by solar-assisted pressure temperature swing adsorption (SOL-PTSA) is studied on the effects of adsorbent materials. A detailed cycle description is firstly presented within the diagram of adsorption isotherm for the energy-efficiency analysis. Typical adsorbent materials, including zeolites and chemical adsorbent, are assessed in terms of sensible heat and latent heat, etc. Then, the energy consumption and the second-law efficiency, which can be considered as lumped indicators from such material parameters, are chosen as performance indicators as well. The influence of separation temperature, desorption temperature, CO2 concentration and CO2 adsorption pressure on system performance are finally obtained. For the chosen three adsorbent materials, the energy consumption of SOL-PTSA system is at the range of 25.96–87.76 kJ/mol, and the corresponding second-law efficiencies are at the range of 9.18–26.89%. The effect of adsorbent materials on the energy-efficiency of SOL-PTSA system mainly depends on specific heat, CO2 working capacity and cycle design. In addition, the integration options of solar energy into PTSA technology are also discussed from the standpoint of the utilization of solar grade heat due to two energy loads required for PTSA's operation.

  • 2693.
    Zheng, W.
    et al.
    Tianjin University, Tianjin, China.
    Hennessy, Jay
    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.
    Reducing renewable power curtailment and CO2 emissions in China through district heating storage2020Inngår i: Wiley Interdisciplinary Reviews: Energy and Environment, ISSN 2041-8396, E-ISSN 2041-840X, Vol. 9, nr 1, artikkel-id e361Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Emissions reductions are often achieved through the increased share of renewable energy sources (RES) and China is the leader in the growth of RES in the power sector. This growth has led to high levels of curtailment of RES power due to insufficient reinforcement of the electricity grid to support such growth and due to competition with other power sources. Although the problem of curtailment has been alleviated in recent years, large amounts of power are still discarded, and it is important to consider how to address this problem in the short term and how much CO2e emissions could be avoided as a result. The use of district heating systems to reduce the curtailment of renewable power has seen increasing interest in recent years. Based on a review of potential energy storage in district heating, the current paper assesses the capability to use the national storage potential of district heating systems in China to reduce curtailment and to determine what effects that may have on avoiding CO2e emissions. The distribution networks and the thermal inertia of buildings connected to district heating are considered as two major forms of storage that can be “charged” using power that would otherwise be curtailed. The results show that there may be sufficient storage available to absorb all renewable power that is currently curtailed in those provinces using district heating during the heating season, resulting in avoided emissions of up to 14 MtCO2e/annum. This article is categorized under: Energy and Climate &gt; Economics and Policy Wind Power &gt; Climate and Environment Energy Infrastructure &gt; Climate and Environment Energy and Urban Design &gt; Climate and Environment.

  • 2694.
    Zhu, C.
    et al.
    Building Energy Research Center, Department of Building Science, Tsinghua University, Beijing, China; Oak Ridge National Laboratory, Building Equipment Research, Energy & Transportation Science Division, Oak Ridge, United States.
    Gluesenkamp, K. R.
    Oak Ridge National Laboratory, Building Equipment Research, Energy & Transportation Science Division, Oak Ridge, United States.
    Yang, Z.
    Lyle School of Civil Engineering, Purdue University, West Lafayette, United States.
    Blackman, Corey
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. SaltX Technology AB, Stockholm, Sweden; Dalarna University, Borlänge, Sweden.
    Unified thermodynamic model to calculate COP of diverse sorption heat pump cycles: Adsorption, absorption, resorption, and multistep crystalline reactions2019Inngår i: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 99, s. 382-392Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A straightforward thermodynamic model is developed in this work to analyze the efficiency limit of diverse sorption systems. A method is presented to quantify the dead thermal mass of heat exchangers. Solid and liquid sorbents based on chemisorption or physical adsorption are accommodated. Four possible single-effect configurations are considered: basic absorption or adsorption (separate desorber, absorber, condenser, and evaporator); separate condenser/evaporator (two identical sorbent-containing reactors with a condenser and a separate direct expansion evaporator); combined condenser/evaporator (one salt-containing reactor with a combined condenser/evaporator module); and resorption (two sorbent-containing reactors, each with a different sorbent). The analytical model was verified against an empirical heat and mass transfer model derived from component experimental results. It was then used to evaluate and determine the optimal design for an ammoniate salt-based solid/gas sorption heat pump for a space heating application. The effects on system performance were evaluated with respect to different working pairs, dead thermal mass factors, and system operating temperatures. The effect of reactor dead mass as well as heat recovery on system performance was also studied for each configuration. Based on the analysis in this work, an ammonia resorption cycle using LiCl/NaBr as the working pair was found to be the most suitable single-effect cycle for space heating applications. The maximum cycle heating coefficient of performance for the design conditions was 1.50 with 50% heat recovery and 1.34 without heat recovery. 

  • 2695.
    Zhu, K.
    et al.
    Tianjin University of Commerce, China.
    Cui, Z.
    Tianjin University of Commerce, China.
    Wang, Y.
    Tianjin University of Commerce, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin University of Commerce, China.
    Zhang, X.
    ABB Corporate Research, Sweden.
    Franke, C.
    Estimating the maximum energy-saving potential based on IT load and IT load shifting2017Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 138, s. 902-909Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cooling system consumes more than 35% of total electricity in most data centers. The provided cooling normally exceeds the actual demand of IT equipment in order to assure the safe operation, resulting in a low energy efficiency. In this paper, a novel method based on demand response was proposed to precisely control the cooling supply, and the energy saving potential was assessed systematically. Compared to the reference case, in which the cooling demand is determined by assuming all of servers are in the running status, when the cooling demand was determined based on the measured dynamic IT load at room level, row level, rack level and server level, it can be reduced by 7.9%, 14.2%, 15.6% and 17.9% respectively for the random selected 48 h. In addition, IT load shifting also has a big potential to save energy, as it can make the cooling system working at a higher energy efficiency, which varies with loads. Two cases were studied: even distribution of IT load and optimized IT load shifting. Compared to the best case that determines the cooling demand according to the IT load at server level, they can further reduce the electricity consumption of cooling systems by 0.9%, and 1.2%. 

  • 2696.
    Zhu, K.
    et al.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Li, X.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Chen, X.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Wang, Y.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Optimization of a loop heat pipe (LHP) with wick separated from heating surface2019Inngår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 2409-2416Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A novel LHP, in which the wick is separated from the heating surface, has been proposed. And then, a steam chamber is formed, which can effectively use the pressure head of evaporation. This work is to optimize the key parameters in order to further improve the performance of such a novel LHP. A mathematical model, based on the node analysis method, had been established, which was validated against the experimental data. The height of steam chamber, the type of working fluids, and the material of wick were identified as key parameters to be optimized. The heating surface temperature, which was the highest temperature, and the start-up time were selected as the key performance indicators. Results showed there existed an optimal height of steam chamber (3mm) and charging ratio (55%) to achieve the lowest heating surface temperature and the shortest start-up time. For different working fluids, ammonia showed the best performance, followed by acetone, ethanol, and water. And the ceramic wick, with low thermal conductivity, demonstrated a better performance than the steel-nickel wick and copper wick with high thermal conductivity.

  • 2697.
    Zhu, K.
    et al.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Li, X.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Yang, Z.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Wang, Y.
    Tianjin Key Laboratory of Refrigeration technology, Tianjin University of Commerce, Tianjin 300134, China.
    Experimental investigation on the effect of heat sink temperature on operational characteristics of a new-type loop heat pipe2019Inngår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 2423-2429Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the development of the miniaturization and the high integration of electronic chip, the thermal management of the high power electronic becomes a major challenge. In this paper the influence of heat sink temperature on operational characteristics was comprehensively conducted and the 35% of charging ratio was selected through the experiment study. To evaluate the LHP system, temperatures, start-up time, thermal resistance, and evaporator heat transfer coefficient were selected as performance indicators. The result showed that, there existed an optimal heat sink temperature (18 o C) to obtain the lowest evaporator bottom temperature (77 o C), the shortest start-up time (1000s), the smallest thermal resistance (0.29k/W), and the highest evaporator heat transfer coefficient (3.110 4 W/(m 2 ·k)). The temperature range to keep a high performance of LHP system was 14-20 o C. The conclusion obtained through the experiment can provide the reference of design the cooling system when the LHP system applied into the electric cooling.

  • 2698.
    Zhu, K.
    et al.
    Tianjin University of Commerce, Tianjin, China.
    Li, X.
    Tianjin University of Commerce, Tianjin, China.
    Wang, Y.
    Tianjin University of Commerce, Tianjin, China.
    Chen, X.
    Tianjin University of Commerce, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dynamic performance of loop heat pipes for cooling of electronics2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 4163-4168Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With the performance improvement of electronics, the recent trends in electronic industry pose a big challenge on heat dissipation. Conventional methods, i.e. air cooling, may not be able to handle the fast increasing heat flux. Using heat pipes, which have numerous advantages such as high heat transfer coefficient, non-movable components, longer transport distance, and compact structures, emerges to be one competitive option for electronics cooling. Based on the node analysis method and the conservation of energy and mass, this work develops a mathematic model to simulate the operation of heat pipes. After it is validated against experimental data, it is further applied to evaluate the dynamic performance of using a heat pipe for electronics cooling. Results show that the operation temperature of evaporator ranges from 47.5°C to73.1°C, which implies that the heat pipe can effectively cool down the CPU at different running status. The charging ratio of working fluid is identified as a key parameter and exists an optimal value. When keeping the charging ratio constant, a larger evaporator area can achieve a lower operating temperature. 

  • 2699.
    Zhu, K.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Li, Xueqiang
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science & Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Techno-economic feasibility of integrating energy storage systems in refrigerated warehouses2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 216, s. 348-357Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work evaluates the techno-economic feasibility of integrating the cold energy storage system and the electrical energy storage system in a refrigerated warehouse for shifting the power consumption. A dynamic model has been developed in TRNSYS®. Based on the dynamic simulation, the performance and benefit of those two types of energy storage systems were compared. Results showed that, the integration of a cold energy storage can reduce the electricity consumption and operational cost by 4.3% and 20.5%, respectively. Even though integrating a battery system will increase the electricity consumption by 3.9%, it can reduce the operational cost by 18.7%. The capacity of the energy storage systems, the battery price and the peak electricity price had been identified as key parameters affecting the performance and benefit. To achieve a payback period less than 3 year, for the integration of a cold energy storage system, the peak electricity price should be increased by 25% from the current level, while for the integration of a battery system, the battery price should drop to 0.7 kRMB/kWh.

  • 2700.
    Zhu, K.
    et al.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Li, Xueqiang
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Chen, X.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Wang, Y.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Experimental and theoretical study of a novel loop heat pipe2018Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 130, s. 354-362Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to reduce the heat leakage from the evaporator and achieve a longer transport distance, a new type of loop heat pipe (LHP) has been proposed based on a hypothesis that the circulation of working fluids is driven by not only the capillary head, but also the pressure head due to evaporation. In the evaporator, the wick is separated from the heating surface by a chamber, which can effectively use the pressure head generated by evaporation. In this work, a prototype of such a LHP was studied experimentally and theoretically. In order to understand the mechanism of operation, a new mathematical model was established. Comparing the simulated results with the experimental data about the operation temperature, a good agreement was observed that the average absolute deviation and the maximum absolute deviation were in ranges of 0.67–1.21 °C and −1.3 to 6 °C, respectively. With the validated model, the two driving forces were investigated. Results showed that the ratio of the pressure head of evaporation to the capillary head was in a range of 59–54% corresponding to heating powers from 30 W to 110 W. It confirms that the pressure head due to evaporation plays an important role in the circulation of working fluids.

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