1,720,975 research outputs found
A novel solar-geothermal district heating, cooling and domestic hot water system: Dynamic simulation and energy-economic analysis
No full textA new methodology for numerical simulation of geothermal down-hole heat exchangers
No full textThis paper presents a numerical procedure for the simulation of heat and fluid flow in a
heat exchange system for exploitation of low enthalpy geothermal reservoirs. The
authors employ for the first time the generalised model for the mathematical description
of heat and fluid flow through saturated porous media in order to study down-hole heat
exchanger, well and aquifer, using a single domain approach. Steady state operation of
the system is considered and the results obtained are validated against experimental data
collected for a geothermal convector prototype installed in an existing geothermal well
on the island of Ischia in southern Italy. The comparison shows that the proposed
procedure can be successfully used for the simulation of this type of problems, and
represents an excellent tool for down-hole heat exchangers optimization. The results of
the present model are employed here to analyse the approximate boundary conditions
that were previously developed for the simulation of a simplified aquifer model
Analisi numerica delle proprietá effettive di manufatti realizzati in opera ai fini della verifica termoigrometrica di ponti termici
No full textNew solutions for axial flow convection in porous and partly porous cylindrical domains
No full textIn this work, fully explicit numerical solutions for axial flow convection in cylindrical domains, completely
or partially filled with a fluid saturated porous medium, are presented. Laminar natural convection
in a vertical porous annulus and in a vertical annulus with a centrally located heat generating solid or
porous rod, and laminar forced convection in a pipe partially filled with a porous medium are numerically
simulated. Novel stability conditions are carried out for the axisymmetric version of the Artificial Compressibility
(AC) Characteristic Based Split (CBS) algorithm, based on finite elements, in order to effectively
solve the above problems. The results presented in this paper are validated against experimental
and numerical data available from the literature. The problem taking into account the presence of the
porous rod in the vertical annulus has been presented here for the first time
Integrating life cycle assessment and emergy synthesis for the evaluation of a dry steam geothermal power plant in Italy
No full textModels for thermo-fluid dynamic phenomena in low enthalpy geothermal energy systems: A review
No full text
Numerical solutions of double diffusion in cavities
No full textIn this work, steady-state thermosolutal convection in a square cavity, subject to horizontal
temperature and concentration gradients, is numerically simulated by using a new efficient matrix
inversion free numerical procedure. The algorithm is based on the explicit Artificial
Compressibility (AC) version of the Characteristic Based Split (CBS) scheme, opportunely
stabilized by the authors to solve Double Diffusion problems. Rectangular cavities with different
aspect ratios, subject to Dirichlet and Neumann boundary conditions, have been considered as
computational domain. The thermal and solutal buoyancy forces acting on the fluid have been taken
into account in case of aiding and opposing flow condition. All the results presented in this paper
have been validated against the numerical and experimental data available from the literature
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
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