1,721,063 research outputs found
CO2 emission reduction from multigeneration systems: evaluation of combined cooling heat and power scenarios
No full textReal-time demand response from energy shifting in distributed multi-generation
No full textIn this paper, a comprehensive dedicated framework is set up to analyze distributed multi-generation (DMG) systems for the purpose of identifying and quantifying their potential to participate in real-time demand response (DR) programmes. At first, flexibility of DMG systems with multiple interconnected plant components is exploited to identify the optimal operational strategy in the presence of half-hourly pricing. Then, the costs and benefits of providing further real-time DR are assessed by taking into account different energy shifting strategies. The novel concept of electricity shifting potential is introduced to establish the upper limit to the possible reduction of the electricity flowing from the electrical grid to the DMG system. The maximum profitable energy shifting that can be activated in the presence of given DR incentives is established on the basis of a DR profitability map. The key point is that energy shifting can be deployed inside the local DMG system to respond to given DR signals without reducing the users' energy demand and thus without affecting their comfort level. Examples of real-time DR for a trigeneration system referring to half-hourly periods during selected Summer and Winter days are illustrated and discussed. © 2010-2012 IEEE
Distributed Multi-Generation: a Comprehensive View
No full textThe recent development of efficient thermal prime movers for distributed generation is changing the focus of the production of electricity from large centralized power plants to local generation units scattered over the territory. The scientific community is addressing the analysis and planning of distributed energy resources with widespread approaches, taking into account technical, environmental, economic and social issues. The coupling of cogeneration systems to absorption/electric chillers or heat pumps, as well as the interactions with renewable sources, allow for setting up multi-generation systems for combined local production of different energy vectors such as electricity, heat (at different enthalpy levels), cooling power, hydrogen, various chemical substances, and so forth. Adoption of composite multi-generation systems may lead to significant benefits in terms of higher energy efficiency, reduced CO2 emissions, and enhanced economy. In this light, a key direction for improving the characteristics of the local energy production concerns the integration of the concepts of distributed energy resources and combined production of different energy vectors into a comprehensive distributed multi-generation (DMG) framework that entails various approaches to energy planning currently available in the literature. This paper outlines the main aspects of the DMG framework, illustrating its characteristics and summarizing the relevant DMG structures. The presentation is backed by an extended review of the most recent journal publications and reports
Energy and CO2 emission assessment of cooling generation alternatives: a comprehensive approach based on black-box models
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Models and Indicators for Energy and CO2 Emission Assessment of Electric Chillers and Direct-Fired Absorption Chillers
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Matrix modelling of small-scale trigeneration systems and application to operational optimization
No full textCombined production of electricity, heat and cooling power in trigeneration represents a key option for the development of high-efficiency and cost-effective integrated energy systems. The complexity of the possible plant schemes calls for the adoption of general models handling multiple interconnected components and energy flows of various typologies. This paper presents a comprehensive input-output matrix approach aimed at modelling small-scale trigeneration equipment taking into account the interactions among plant components and external energy networks. Starting from the definitions of specific efficiency matrices for each plant component and from a matrix representation of the relevant interconnections, an overall efficiency matrix representing the whole plant is constructed. This construction is carried out by means of an original procedure, suitable for automatic and symbolic implementation, which, exploiting graph theory concepts, explores the tree formed by the backward paths from outputs to inputs. The proposed formulation maintains the separation among the individual energy vectors, each of which can be associated to its time-dependent price, providing the basic framework for formulating optimization problems concerning management of trigeneration systems within an energy market context. A numerical example referred to the optimal operation of a composite scheme with absorption and electric chillers is illustrated and discussed. The results obtained show the modelling effectiveness of the proposed matrix formulation. © 2008 Elsevier Ltd. All rights reserved
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