Search results for "Energy engineering"
showing 10 items of 1099 documents
An original multi-objective criterion for the design of small-scale polygeneration systems based on realistic operating conditions
2008
The optimal design and operation of cogeneration and trigeneration systems for buildings applications is a complex issue, which has been investigated by several different approaches. Both the two basic management strategies, namely heat-tracking and electricity-tracking, have advantages and drawbacks in terms of operating results and may lead the plant designer either to undersize or oversize the CHP unit with respect to the optimal lay-out. Experimental works have demonstrated how the actual on-site performance of small-scale polygeneration systems significantly differs from their expected operation, due to the need for a regular plant operation and the effects of outages for scheduled or …
Regression analysis to design a solar thermal collector for occasional use
2020
Abstract Optimal design of a solar thermal system is necessary to minimize payback time and to diffuse renewable energy use for Domestic Hot Water production in residential areas. More accurate design is crucial in the case of seasonal or occasional use of the system; indeed, the standard criteria generally applied to a design system for continuous use, can lead to considerable over-sizing. To speed up the design phase and to help the planner in the identification of the best solution without any complex evaluation or long computational time, it would be interesting to have available a simpler method than the standard procedures, but one that is reliable and accurate for the evaluation of t…
Modeling of light pipes for the optimal disposition in buildings
2019
A light pipe is an excellent solution to transport and distribute daylight into environments without or with little lighting, guaranteeing comfort inside the rooms. As stated in the literature, the evaluation of the performances of light pipes presents numerous complexities, making the work very difficult for technicians and designers. This study is aimed to present a methodology that is able to identify the potential of light pipes using indices such as daylight autonomy (DA), continuous daylight autonomy (DAc), and useful daylight illuminance (UDI). This paper presents an analysis of daylight obtained by several configurations of simple models of light pipes installed into a 5 ×
Improving efficiency and discharge power of acid-base flow battery via a bi-objective optimisation
2023
Matching Economical, Energetic and Environmental Benefits: An Analysis for Hybrid CHCP-Heat Pumps Systems
2006
Abstract The optimization of design and operation of combined heat, cooling and power systems usually leads to select different plant lay-outs and size of components, depending on the adopted optimization criterion (maximum profit or energy saving or minimum environmental impact). This occurs when the current energy prices and the normative provisions supporting cogeneration are not able to coincide with the specific customer’s interest and the overall “social interest” for a reduction in energy consumption and in pollutants’ emissions. At EU level, polygeneration is considered to have a large potential for residential and commercial buildings district network, for the tertiary sector and f…
On the Reliability of Optimization Results for Trigeneration Systems in Buildings, in the Presence of Price Uncertainties and Erroneous Load Estimati…
2016
Cogeneration and trigeneration plants are widely recognized as promising technologies for increasing energy efficiency in buildings. However, their overall potential is scarcely exploited, due to the difficulties in achieving economic viability and the risk of investment related to uncertainties in future energy loads and prices. Several stochastic optimization models have been proposed in the literature to account for uncertainties, but these instruments share in a common reliance on user-defined probability functions for each stochastic parameter. Being such functions hard to predict, in this paper an analysis of the influence of erroneous estimation of the uncertain energy loads and pric…
Optimization of trigeneration systems by Mathematical Programming: Influence of plant scheme and boundary conditions
2015
Abstract The large potential for energy saving by cogeneration and trigeneration in the building sector is scarcely exploited due to a number of obstacles in making the investments attractive. The analyst often encounters difficulties in identifying optimal design and operation strategies, since a number of factors, either endogenous (i.e. related with the energy load profiles) and exogenous (i.e. related with external conditions like energy prices and support mechanisms), influence the economic viability. In this paper a decision tool is adopted, which represents an upgrade of a software analyzed in previous papers; the tool simultaneously optimizes the plant lay-out, the sizes of the main…
Exergetic and exergoeconomic analysis of a novel hybrid solar-geothermal polygeneration system producing energy and water
2016
Abstract A dynamic simulation model of a novel solar–geothermal polygeneration system and the related exergetic and exergoeconomic analyses are presented in this paper. The plant is designed in order to supply electrical, thermal and cooling energy and fresh water for a small community, connected to a district heating and cooling network. The hybrid system is equipped with an Organic Rankine Cycle fueled by medium-enthalpy geothermal energy and by a Parabolic Trough Collector solar field. Geothermal brine is also used for space heating and cooling purposes. Finally, geothermal fluid supplies heat to a Multi-Effect Distillation unit, producing also desalinized water from seawater. Dynamic si…
Energy management of a thermally coupled fuel cell system and metal hydride tank
2019
International audience; Being produced from renewable energy, hydrogen is one of the most efficient energy carriers of the future. Using metal alloys, hydrogen can be stored and transported at a low cost, in a safe and effective manner. However, most metals react with hydrogen to form a compound called metal hydride (MH). This reaction is an exothermic process, and as a result releases heat. With sufficient heat supply, hydrogen can be released from the as-formed metal hydride. In this work, we propose an integrated power system of a proton exchange membrane fuel cell (PEMFC) together with a hydride tank designed for vehicle use. We investigate different aspects for developing metal hydride…
Simulation and experimental validation of multicarrier PWM techniques for three-phase five-level cascaded H-bridge with FPGA controller
2017
The FPGA represents a valid solution for the design and implementation of control systems for inverters adopted in many fields of power electronics because of its high flexibility of use. This paper presents an overview and an experimental validation of the MC SPWM techniques for a three-phase, five-level, cascaded H-Bridge inverter with FPGA controller-based. Several control algorithms are here implemented by means of the VHDL programming language and the output voltage waveforms obtained from the main PWM techniques are compared in terms of THD%. Simulation and experimental results are analyzed, compared and discussed.