1,720,975 research outputs found
An application of a novel operational strategy for combined heat and power systems
No full textIn this work an application of a novel strategy for
the operation of combined heat and power
(CHP) systems is analysed considering the
results of an optimization analysis performed by
means of a home-made code written in Matlab,
and the ones relative to dynamic simulations
carried out using the commercial software
TRNSYS 17. Such approach is mainly devoted
to CHP systems operating without load
modulation, and it is similar to the classical heat-
driven operational strategy, except for the
possibility to dump part of the heat produced by
cogenerators. The differences between the
present approach and the heat-driven strategy
without heat dumping are shown for a case
study represented by a residential micro-CHP
system, composed of a prime mover, a thermal
energy storage system and an auxiliary boiler,
producing electricity and heat for a single-family
house located in Italy. In particular, it is shown
that heat dumping can involve a considerable
reduction of the heat storage system size, with a
negligible decrease of the useful energy
produced by the micro-CHP system
Comparison between two different operation strategies for a heat-driven residential natural gas-fired CHP system: Heat dumping vs. load partialization
No full textEconomic optimization of a residential micro-CHP system considering different operation strategies
No full text
A new approach for the dimensioning of an air conditioning system with cold thermal energy storage
No full textIn this work, a new approach for the design of air conditioning systems with cold thermal energy storage is described and tested, considering the case study represented by a vapor-compression chiller, coupled with a chilled water storage system, producing cooling for a small multi-apartment building situated in Italy. In the present approach, at the aim of limiting shut-downs and start-ups of the chiller, which involve inefficiencies during transients, and can lead to a drastic reduction of the equipment lifetime, the nominal power of the chiller, and the amount of cooling to be stored are first estimated in a pre-design phase. Successively, the outputs of the pre-design are used to fix the size of the cold storage tank, and to set up the numerical simulation of the cold thermal energy storage system. Finally, the results of the numerical simulation of the cold storage system are used to evaluate the effective size of the chiller. Both the pre-design and the numerical simulations of the cold storage systems have been done by means of homemade numerical tool realized with Simulink. In the paper, the specifications relative to the operational strategy are explored, and the analytical models used for the numerical simulation of the cold storage system relative to the Italian case study are reported in detail. Finally, the results of the pre-design, and of the cold storage system simulations relative to the case study are presented and discussed. The results relative to the Italian case study demonstrates the effectiveness of the present approach in limiting the number of shut-downs and start-ups of the chiller. The present approach can represent a useful tool for the economic optimization of the design of air conditioning systems
Optimal operation of residential micro-CHP systems with thermal storage losses modelling
No full textIn this study the optimal operation of micro-CHP systems producing electricity and heat for a single-family house situated in Italy is addressed considering the effects of heat dissipation relative to thermal storage systems. Three different prime movers have been analyzed separately, and for each of them the operation scheduling that maximizes the revenues for the energy cogeneration with respect to the separate generation has been evaluated by means of an optimization algorithm
Analysis of a biomass-fired CCHP system considering different design configurations
No full textThis work aims to present the results of an energetic and economic analysis of a biomass fueled CCHP system operating according to different design configurations. The investigated system consists of a biomass-fueled cogeneration unit, an absorption chiller, a thermal energy storage system and a cold one, providing electricity, heat and cooling to an Italian cluster of buildings. For each simulated configuration, the feasible investment cost of the CHP unit is evaluated considering the economic savings obtained with respect to separate generation of electricity, heat and cooling. The best configuration from the economic point of view is indicated, and the incidence of the variation of the absorption chiller and storage systems sizes on the feasible investment cost of the CHP unit is evaluated and discussed as well. Results indicate that the most influencing parameter is represented by the absorption chiller power
Optimal operation of micro-CHP systems for a single-family house in Italy
No full textIn this work the scheduling optimization of micro-CHP systems producing electricity and heat for a
single-family house situated in Italy is addressed. Three different commercial prime movers have
been analyzed separately, and for each of them the operation scheduling that maximizes the revenues
for the energy cogeneration with respect to the separate generation has been evaluated by means of an
optimization algorithm
Transient analysis of a solar domestic hot water system using two different solvers
No full textAbstractIn the present work the unsteady numerical simulation of a solar domestic hot water (DHW) system composed of two flat plate collectors, a water tank for heat storage, and a coil heat exchanger is addressed. The simulations have been performed using two different solvers, namely a home-made code written in Matlab, and TRNSYS 17. In the first part of the paper, the analytical models used in the Matlab code, and the TRNSYS case are reported in detail. Successively, the results of the simulations realized by means of the two solvers are presented and compared
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