1,720,963 research outputs found
Optimal synthesis and operation of advanced energy supply systems for standard and domotic home
No full texthe paper deals with the optimization of an advanced energy supply systems for two dwellings: a standard home and an advanced domotic home, where some demand side energy saving strategies have been implemented. In both cases the optimal synthesis, design and operation of the whole energy supply system have been obtained and a sensitivity analysis has been performed, by introducing different economic constraints. The optimization model is based on a Mixed Integer Linear Program (MILP) and includes different kinds of small-scale cogenerators, geothermal heat pumps, boilers, heat storages, solar thermal and photovoltaic panels. In addition, absorption machines, supplied with cogenerated heat, can be used instead of conventional electrical chiller to face the cooling demand. The aim of the analysis is to address the question if advanced demand strategies and supply strategies have to be regarded as alternatives, or if they have to be simultaneously applied, in order to obtain the maximum energy and economic benefit
Mixed Integer Linearized Exergoeconomic (MILE) method for energy system synthesis and optimization
No full textThe aim of the paper is to present an energy system optimization method, based on the Fuel Impact Formula, able to overcome typical limitations of previous formulations. In particular, the methodology allows time dependent production levels to be considered and on-off operation and presence-absence of any component to be modelled by means of binary decision variables and inequality constraints. These often happen if the synthesis and operation of Combined Heat and Power (CHP) systems are considered at the same time. Moreover, the effect of replacing actual not linear thermodynamic inputs-output relations of each component with linear, or even proportional ones, is highlighted in the paper. Finally, an example of application is shown, dealing with a multi-component DH and CHP system in the tertiary sector
A comparison of different district integration for a distributed generation system for heating and cooling in an urban area
Full text linkThe paper proposes a comparison of dierent district integration options for a distributed
generation system for heating and cooling in an urban area. The system considered includes several
production units located close to the users, a central unit and the district heating and cooling network
which can connect all the users to each other and to a central unit, where a cogeneration system and a
solar plant can be placed. Thus, each user can be regarded as isolated from the others, satisfying
its energy needs by means of an autonomous production unit. Alternatively, it can be connected to
the others through the district heating and cooling network. When a district heating and cooling
network is included in the design option the synthesis-design and operation problems cannot be
solved separately, because the energy to be produced by each production site is not known in advance,
as the flows through the district heating and cooling network are not defined. This paper uses
a mixed integer linear programming (MILP) methodology for the multi-objective optimization of
the distributed generation energy system, considering the total annual cost for owning, operating
and maintaining the whole system as the economic objective function, while the total annual CO2
emissions as the environmental objective function. The energy system is optimized for dierent
district integration option, in order to understand how they aect the optimal solutions compared
with both the environmental and economic objects
Optimization of Distributed Trigeneration Systems Integrated with Heating and Cooling Micro-grids
No full textThe paper deals with the influence of the amortization period in the optimization of a distributed urban district heating and cooling trigeneration system. The model, presented in detail in [1], is based on a Mixed Integer Linear Program (MILP) and includes a set of micro-cogeneration gas turbines for producing electricity and thermal energy and a set of absorption chillers, driven by cogenerated heat, for producing cooling energy. Micro-gas turbines and absorption chillers can be used instead of purchasing electricity from the grid, producing thermal energy by boilers and cooling energy by compression chillers. Moreover, various building can be connected each other through a district heating and cooling network (DHC network). The optimization specifies the kind, the number and the location of cogeneration equipment and absorption machines, the size and the position of district heating and cooling pipelines as well as the optimal operation of each component. The objective function takes into account investment cost of micro-gas turbine, absorption chillers and DHC network, maintenance costs, operation costs and any income from the sale of electricity.
The aim of the paper is to obtain the optimal solution varying the amortization period of machines and networks, for understanding the influence of capital costs on the annual total cost, the optimal system configuration and operation
Ottimizzazione di un sistema di cogenerazione distribuita integrato con pannelli solari e accumulo termico a servizio di un’area industriale
No full textLo studio tratta l’ottimizzazione di un sistema di fornitura energetica di un’area industriale. Il modello è lineare misto-intero e consente di determinare la configurazione ottima del sistema, la taglia dei componenti e la miglior strategia operativa. L’obiettivo è identificare il mix energetico ottimo che soddisfi le richieste delle utenze, confrontare l’alimentazione con fonti rinnovabili alla soluzione cogenerativa e alla fornitura convenzionale e valutare i benefici economici e ambientali
Optimal lay-out and operation of district heating and cooling distributed trigeneration systems
No full textThe paper deals with the optimization of a distributed urban district heating and cooling cogeneration system. The model is based
on a Mixed Integer Linear Program (MILP) and includes a set of micro-cogeneration gas turbines and a district heating network
potentially connecting each considered building to all the others. Absorption machines, supplied with cogenerated heat, can be used
instead of conventional electrical chiller to face the cooling demand. In addition, a district cooling network can be introduced,
independently from the district heating one.
The objective of the paper is to obtain the optimal synthesis and operation strategy of the whole system, in terms of Total Annual
Cost for owning, maintaining and operating the system. The solution has to specify the kind, the number and the location of
cogeneration equipment and absorption machines, the size and the position of district heating and cooling pipelines as well as the
optimal operation of each component. The effects of different plant options, comparing cogeneration and tri-generation machines
adoption and district heating and cooling pipelines installation, are considered
Optimization of an Industrial Area Energy Supply System with Distributed Cogeneration and Solar District Heating
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Optimization of an industrial area Energy Supply Systems with distrubuted cogeneration and solar district heating
No full textThe paper presents the optimization of an energy supply system for an Italian industrial area. The system is mainly composed of a district heating network (DHN), of a thermal solar plant with seasonal heat storage, of a set of combined heat and power units (CHP) and of additional thermal energy supply machines. The thermal vector can be produced by solar thermal modules, by biogas/biomass cogeneration systems, by fossil-fuel cogenerators or by conventional boilers. The optimization algorithm, based on a Mixed Integer Linear Programming (MILP) model, has to determine the optimal structure of the energy system and the size of the components (solar plant area, heat storage volume, machines sizes, etc.). The model allows to calculate the economical and environmental benefits of the solar thermal plant compared to the cogenerative production, as well as the share of the thermal demand covered by renewable energies. The aim of the paper is to identify the economical conditions that make the usage of the renewable energy sources effective and how these conditions affect the optimal energy system configuration and the optimal input energy mix required to satisfy the users energy demands.
The average cost of the heat produced for the users have been evaluated for different optimal configurations, and it emerges that the solution including some cogenerators located in strategic production units, the district heating network, the seasonal heat storage and the solar plant of appropriate size allow achieving the lowest cost of the heat. Thus, the integrated solution turns out to be the best both from the economical and environmental point of view
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