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- Huang, Pei, et al.
(author)
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Transforming a residential building cluster into electricity prosumers in Sweden : Optimal design of a coupled PV-heat pump-thermal storage-electric vehicle system
- 2019
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 255
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Journal article (peer-reviewed)abstract
- Smart grid is triggering the transformation of traditional electricity consumers into electricity prosumers. This paper reports a case study of transforming an existing residential cluster in Sweden into electricity prosumers. The main energy concepts include (1) click-and-go photovoltaics (PV) panels for building integration, (2) centralized exhaust air heat pump, (3) thermal energy storage for storing excess PV electricity by using heat pump, and (4) PV electricity sharing within the building cluster for thermal/electrical demand (including electric vehicles load) on a direct-current micro grid. For the coupled PV-heat pump-thermal storage-electric vehicle system, a fitness function based on genetic algorithm is established to optimize the capacity and positions of PV modules at cluster level, with the purpose of maximizing the self-consumed electricity under a non-negative net present value during the economic lifetime. Different techno-economic key performance indicators, including the optimal PV capacity, self-sufficiency, self-consumption and levelized cost of electricity, are analysed under impacts of thermal storage integration, electric vehicle penetration and electricity sharing possibility. Results indicate that the coupled system can effectively improve the district-level PV electricity self-consumption rate to about 77% in the baseline case. The research results reveal how electric vehicle penetrations, thermal storage, and energy sharing affect PV system sizing/positions and the performance indicators, and thus help promote the PV deployment. This study also demonstrates the feasibility for transferring the existing Swedish building clusters into smart electricity prosumers with higher self-consumption and energy efficiency and more intelligence, which benefits achieving the ‘32% share of renewable energy source’ target in EU by 2030.
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- Lovati, Marco, et al.
(author)
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Agent Based Modelling of a Local Energy Market : A Study of the Economic Interactions between Autonomous PV Owners within a Micro-Grid
- 2021
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In: Buildings. - : MDPI AG. - 2075-5309. ; 11:4
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Journal article (peer-reviewed)abstract
- Urban Photovoltaic (PV) systems can provide large fractions of the residential electric demand at socket parity (i.e., a cost below the household consumer price). This is obtained without necessarily installing electric storage or exploiting tax funded incentives. The benefits of aggregating the electric demand and renewable output of multiple households are known and established; in fact, regulations and pilot energy communities are being implemented worldwide. Financing and managing a shared urban PV system remains an unsolved issue, even when the profitability of the system as a whole is demonstrable. For this reason, an agent-based modelling environment has been developed and is presented in this study. It is assumed that an optimal system (optimized for self-sufficiency) is shared between 48 households in a local grid of a positive energy district. Different scenarios are explored and discussed, each varying in number of owners (agents who own a PV system) and their pricing behaviour. It has been found that a smaller number of investors (i.e., someone refuse to join) provokes an increase of the earnings for the remaining investors (from 8 to 74% of the baseline). Furthermore, the pricing strategy of an agent shows improvement potential without knowledge of the demand of others, and thus it has no privacy violations.
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- Lovati, Marco, et al.
(author)
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Optimal Simulation of Three Peer to Peer (P2P) Business Models for Individual PV Prosumers in a Local Electricity Market Using Agent-Based Modelling
- 2020
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In: Buildings. - : MDPI AG. - 2075-5309. ; 10:8
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Journal article (peer-reviewed)abstract
- Solar photovoltaic (PV) is becoming one of the most significant renewable sources for positive energy district (PED) in Sweden. The lack of innovative business models and financing mechanisms are the main constraints for PV’s deployment installed in local communities. This paper therefore proposes a peer-to-peer (P2P) business model for 48 individual building prosumers with PV installed in a Swedish community. It considers energy use behaviour, electricity/financial flows, ownerships and trading rules in a local electricity market. Different local electricity markets are designed and studied using agent-based modelling technique, with different energy demands, cost–benefit schemes and financial hypotheses for an optimal evaluation. This paper provides an early insight into a vast research space, i.e., the operation of an energy system through the constrained interaction of its constituting agents. The agents (48 households) show varying abilities in exploiting the common PV resource, as they achieve very heterogeneous self-sufficiency levels (from ca. 15% to 30%). The lack of demand side management suggests that social and lifestyle differences generate huge impacts on the ability to be self-sufficient with a shared, limited PV resource. Despite the differences in self-sufficiency, the sheer energy amount obtained from the shared PV correlates mainly with annual cumulative demand.
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- Wang, DongPo, et al.
(author)
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Experimental study on physical model of waste tennis ball-sand composite shed cushion under rockfall impact
- 2022
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In: Bulletin of Engineering Geology and the Environment. - : Springer Science and Business Media LLC. - 1435-9529 .- 1435-9537. ; 81:5
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Journal article (peer-reviewed)abstract
- Given the limited dissipating effect and high construction costs of traditional sand cushion in shed, this paper proposes to partially replace the sand with waste tennis balls to solve the problem of poor impact resistance of sand cushion. Tests of the impact of rockfall on the waste tennis ball-sand composite cushion were carried out exploring the dissipation effect controlled for the following: height of the rockfall, average gas content of the tennis balls, distribution density, whether the tennis ball gaps were filled with sand, and prevalence and position of tennis balls. According to the results, when a steel plate is added above the composite cushion to isolate the river sand and the tennis balls, the peak of reaction force and impact force decreased by 62% and 72%, respectively, and the dissipating effect of the composite cushion is significantly improved. More specifically, the energy dissipation of tennis cushion outperforms the traditional one with an increase of falling height, and the peak value of reaction force and impact force decrease by up to 23% and 14%, respectively. Moreover, under the same impact energy, the dissipating effect of the tennis ball-sand composite cushion gradually increases with the reduction of the gas content of the tennis ball and the distance between the tennis balls; 25% gas content and 5 cm distance have the best energy dissipation effect. The research results can provide new solutions for the structural design of cushion and the reuse of used tennis balls. © 2022, Springer-Verlag GmbH Germany, part of Springer Nature.
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- Zhang, Xingxing, et al.
(author)
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A review of urban energy systems at building cluster level incorporating renewable-energy-source (RES) envelope solutions
- 2018
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 230, s. 1034-1056
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Journal article (peer-reviewed)abstract
- The emergence of renewable-energy-source (RES) envelope solutions, building retrofit requirements and advanced energy technologies brought about challenges to the existing paradigm of urban energy systems. It is envisioned that the building cluster approach—that can maximize the synergies of RES harvesting, building performance, and distributed energy management—will deliver the breakthrough to these challenges. Thus, this paper aims to critically review urban energy systems at the cluster level that incorporate building integrated RES solutions. We begin with defining cluster approach and the associated boundaries. Several factors influencing energy planning at cluster scale are identified, while the most important ones are discussed in detail. The closely reviewed factors include RES envelope solutions, solar energy potential, density of buildings, energy demand, integrated cluster-scale energy systems and energy hub. The examined categories of RES envelope solutions are (i) the solar power, (ii) the solar thermal and (iii) the energy-efficient ones, out of which solar energy is the most prevalent RES. As a result, methods assessing the solar energy potentials of building envelopes are reviewed in detail. Building density and the associated energy use are also identified as key factors since they affect the type and the energy harvesting potentials of RES envelopes. Modelling techniques for building energy demand at cluster level and their coupling with complex integrated energy systems or an energy hub are reviewed in a comprehensive way. In addition, the paper discusses control and operational methods as well as related optimization algorithms for the energy hub concept. Based on the findings of the review, we put forward a matrix of recommendations for cluster-level energy system simulations aiming to maximize the direct and indirect benefits of RES envelope solutions. By reviewing key factors and modelling approaches for characterizing RES-envelope-solutions-based urban energy systems at cluster level, this paper hopes to foster the transition towards more sustainable urban energy systems.
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- Zhang, Xingxing, et al.
(author)
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Digital Twin for Accelerating Sustainability in Positive Energy District : A Review of Simulation Tools and Applications
- 2021
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In: Frontiers in Sustainable Cities. - : Frontiers Media SA. - 2624-9634. ; 3
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Research review (peer-reviewed)abstract
- A digital twin is regarded as a potential solution to optimize positive energy districts (PED). This paper presents a compact review about digital twins for PED from aspects of concepts, working principles, tools/platforms, and applications, in order to address the issues of both how a digital PED twin is made and what tools can be used for a digital PED twin. Four key components of digital PED twin are identified, i.e., a virtual model, sensor network integration, data analytics, and a stakeholder layer. Very few available tools now have full functions for digital PED twin, while most tools either have a focus on industrial applications or are designed for data collection, communication and visualization based on building information models (BIM) or geographical information system (GIS). Several observations gained from successful application are that current digital PED twins can be categorized into three tiers: (1) an enhanced version of BIM model only, (2) semantic platforms for data flow, and (3) big data analysis and feedback operation. Further challenges and opportunities are found in areas of data analysis and semantic interoperability, business models, data security, and management. The outcome of the review is expected to provide useful information for further development of digital PED twins and optimizing its sustainability.
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