An Experimental Investigation of a Novel Low-Cost Photovoltaic Panel Active Cooling System

Renewable energy sources are the most useful way to generate clean energy and guide the transition toward green power generation and a low-carbon economy. Among renewables, the best alternative to electricity generation from fossil fuels is solar energy because it is the most abundant and does not release pollutants during conversion processes. Despite the photovoltaic (PV) module ability to produce electricity in an eco-friendly way, PV cells are extremely sensitive to temperature increments. This can result in efficiency drop of 0.25%/ ∘ C to 0.5%/ ∘ C. To overcome this issue, manufacturers and researchers are devoted to the improvement of PV cell efficiency by decreasing operating temperature. For this purpose, the authors have developed a low-cost and high-performance PV cooling system that can drastically reduce module operating temperature. In the present work, the authors present a set of experimental measurements devoted to selecting the PV cooling arrangement that guarantees the best compromise of water-film uniformity, module temperature reduction, water-consumption minimization, and module power production maximization. Results show that a cooling system equipped with 3 nozzles characterized by a spraying angle of 90 ∘ , working with an inlet pressure of 1.5 bar, and which remains active for 30 s and is switched off for 120 s, can reduce module temperature by 28 ∘ C and improve the module efficiency by about 14%. In addition, cost per single module of the cooling system is only 15 €

Environmental Impact of Energy Systems Integrated with Electrochemical Accumulators and Powered by Renewable Energy Sources in a Life-Cycle Perspective

The aim of this study is to assess the environmental impact of storage systems integrated with energy plants powered by renewable sources. Stationary storage systems proved to be a valid solution for regulating networks, supporting frequency, and managing peaks in electricity supply and demand. Recently, their coupling with renewable energy sources has been considered a strategic means of exploiting their high potential since it permits them to overcome their intrinsic uncertainty. Therefore, the storage systems integration with distributed generation can improve the performance of the networks and decrease the costs associated with energy production. However, a question remains regarding the overall environmental sustainability of the final energy production. Focusing on electrochemical accumulators, the problems mainly concern the use of heavy metals and/or impacting chemical components of storage at the center of environmental hazard debates. In this paper, an environmental assessment from a life-cycle perspective of the hybrid energy systems powered by fossil and renewable sources located on two non-interconnected minor islands is presented. Existing configurations are compared with new ones obtained with the addition of batteries for the exploitation of renewable energy. The results show that, for batteries, the assembly phase, including raw material extraction, transport, and assembly, accounts for about 40% of the total, while the remaining part is related to end-of-life processes. The reuse and recycling of the materials have a positive effect on overall impacts. The results also show that the overall impact is strongly related to the actual energy mix of the place where batteries are installed, even if it is usually lower than that of the solution without the batteries. The importance of a proper definition of the functional unit in the analysis is also emphasized in this work

EU energy policies achievement by industries in decentralized areas

Energy Roadmap outlined by the European Commission sets out several routes for a more sustainable, competitive and secure energy system in 2050. All the outlined scenarios consider energy efficiency, renewable energy, nuclear energy and carbon capture and storage. In this paper, more attention has been devoted to the energy efficiency issue, by the identification of new micro and small networks opportunity fed by hybrid plants in the North-East of Italy. National energy balance and national transmission system operator data allowed to collect industrial energy consumptions data on the investigated area. Applying industrial statistics to the local energy needs allows to collect a dataset including consumption information by factory and by company structure (size and employees) for each industrial sector highlighting the factory density in the area. Preliminary outcomes from the model address to the exploitation of local by-product for energy purposes

Fluid Selection and Plant Configuration of an ORC-biomass fed System Generating Heat and/or Power☆

Abstract The aim of the paper is to compare from an energetic, exergetic and economic viewpoint different plant configurations of Organic Rankine Cycles matched with biomass-fired boilers for electricity production or combined heat and power generation. To this purpose, a computer tool able to perform the fluid selection and plant layout optimization has been developed. The devices efficiency charts are used to predict the components performance while the fluid thermodynamic properties have been retrieved from two databases. Results show that Toluene guarantees the highest performance in both cases while the most suitable configuration is the recuperative one

design and off design analysis of an orc coupled with a micro gas turbine

Abstract In the recent years, the possibility of recovering heat from gas turbine (GT) exhaust gases using Organic Rankine Cycles (ORC) have been largely explored. However, it is difficult to identify working fluids properly matching with micro-GT exhaust gases. For this reason, in the present work, the fluid selection and the plant layout optimization of an ORC which recovers the exhaust gases heat content of a 65 kW micro-gas turbine is presented. During the optimization process different plant configurations are considered: simple or regenerative and subcritical or transcritical. Exergy and economic analyses are also performed to estimate the exergy destruction rate and evaluate the economic feasibility of the optimized solutions. In order to find out the most suitable ORC unit and its behaviour, an off-design analysis is also performed using the commercial software Aspen Plus. Adopting a management strategy that maintains the turbine inlet temperature constant the best off-design performance is reached with Cyclopentane as working fluid

improvement of the energy system of a nepali village through innovative exploitation of local resources

Abstract Nepal is one of the less industrialized Countries and does not have fossil fuel reserves. In this scenario, a better exploitation of energy resources is a key factor to start improving the country's overall energy system. For these reasons, the aim of this work, which is the result of a collaboration between two research groups from different countries, is the design of an ORC which recovers the discharged heat by an existing ICE: the integrated system will supply electricity to a small Nepali village, contributing to a little rise of the life standard of a small and poor community

Waste heat recovery technologies for offshore platforms

none5siThis article aims at finding the most suitable waste heat recovery technology for existing and future offshore facilities. The technologies considered in this work are the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle. A multi-objective optimization approach is employed to attain optimal designs for each bottoming unit by selecting specific functions tailored to the oil and gas sector, i.e. yearly CO2 emissions, weight and economic revenue. The test case is the gas turbine-based power system serving an offshore platform in the North Sea. Results indicate that the organic Rankine cycle technology presents larger performances compared to steam Rankine cycle units, whereas the implementation of air bottoming cycle modules is not attractive from an economic and environmental perspective compared to the other two technologies. Despite the relatively high cost of the expander and of the primary heat exchanger, organic Rankine cycle turbogenerators appear thus to be the preferred solution to abate CO2 emissions and pollutants on oil and gas facilities. As a practical consequence, this paper provides guidelines for the design of high-efficiency, cost-competitive and low-weight power systems for offshore installationsrestrictedL. Pierobon;A. Benato;E. Scolari;F. Haglind;A. StoppatoL., Pierobon; Benato, Alberto; E., Scolari; F., Haglind; Stoppato, Ann

Hydrodynamic Cavitation for Pollutant Treatment in the New Horizon of Green Chemistry

The study describes a systematic numerical optimization of a Venturi tube for wastewater treatment under cavitation conditions. The numerical approach employs computational fluid dynamics methodologies in a Reynolds-Averaged Navier-Stokes framework combined with an optimization algorithm to enhance a baseline Venturi geometry. A robust meshing technique is provided in order to define the numerical model associated with the baseline solution. The process compares alternative mesh sizes and turbulence closure to discover the optimal accuracy and processing time balance. Then the model is used as a starting point for the optimization. An optimal configuration is found to be able to improve the tube mean vapor quality by around 130% compared to the starting geometry

Modello per l'analisi delle prestazioni in esercizio della sezione a vapore di un impianto combinato

L’articolo presenta un modello termodinamico per l’analisi in esercizio della sezione a vapore, a due livelli di pressione e cogenerativa, di un impianto combinato. Il modello, che integra un modello precedente per il gruppo turbogas, calcola le prestazioni al variare dei carichi elettrico e termico e di alcune grandezze facilmente misurabili o relative all’ambiente esterno, e perciò note in ogni condizione di funzionamento. Viene presentata l’analisi di sensibilità di alcuni di tali parametri sia sul rendimento sia sulla potenza prodotta. E’ inoltre evidenziato come il modello aiuti a rilevare l’eventuale presenza di un malfunzionamento e a quantificarne l’effetto sulle prestazioni complessive dell’impianto. Nell’articolo è infine presentata un’ipotesi di miglioramento delle prestazioni estive dell’impianto tramite raffreddamento dell’aria aspirata dal compressore del turbogas

Life Cycle Assessment of Photovoltaic Electricity Generation

The paper presents the results of a life cycle assessment (LCA) of the electric generation by means of photovoltaic panels. It considers mass and energy flows over the whole production process starting from silica extraction to the final panel assembling, considering the most advanced and consolidate technologies for polycrystalline silicon panel production. Some considerations about the production cycle are reported; the most critical phases are the transformation of metallic silicon into solar silicon and the panel assembling. The former process is characterised by a great electricity consumption, even if the most efficient conversion technology is considered, the latter by the use of aluminium frame and glass roofing, which are very energy-intensive materials. Moreover, the energy pay back time (EPBT) and the potential for CO2 mitigation have been evaluated, considering different geographic collocations of the photovoltaic plant with different values of solar radiation, latitude, altitude and national energetic mix for electricity production