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 €

Biogas engine waste heat recovery using organic Rankine cycle

Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs). Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC) technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions

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

Biogas Engine Emissions: Standards and On-Site Measurements

Abstract The European Union, with 60% of the total global production of biogas, is the world leader. In 2012, the percentage of electrical energy produced by biogas was 6% of the EU-28 electricity generated through renewable sources while, in 2013, the almost 830 biogas units produced 7448 GWh which corresponds to 14% of EU-28 gross electricity production. Germany, U.K. and Italy are the main EU biogas producers with over 78% of the 2013 primary energy production. Electricity production is the main biogas energy recovery form because the engine cooling water is used to maintain the digester required temperature while energy crops and manure are the most used organic matters. Spark-ignition engines with a rated power of 1MWel in which the filtered biogas is burned to produce work is the widely-adopted technology. With the aim of analyzing the emissions of a real biogas engine, in the present work, the authors firstly present an overview of the Italian biogas sector and the most used conversion technologies. Then, the standards which regulate the biogas plant emissions and the emissions data acquired during a one-year monitoring activity on 10 biogas plants are presented and discussed with the aim of assessing the biogas units' real emissions

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

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

study and simulation of a hydraulic hybrid powertrain

Abstract In the agricultural and work machine sectors, the hydro-mechanical transmission competes with traditional mechanical transmission; a tool to improve its competitiveness is the hybridization. The hydraulic branch of the transmission may be integrated with two accumulators which allow the storage of energy derived from braking; the presence of the two hydraulic units facilitates this solution: the hydraulic motor acts as a pump during the braking and as a motor during the starts of the vehicle. This solution appears to be interesting also from the costs point of view, because it does not require a high-level technology. For this reason, in the present work, the hybrid hydro-mechanical transmission is studied with the aim of pointing out its potential for the urban passenger transport sector. At first, a hydro-mechanical transmission for an urban bus is designed; then, the same transmission is modified adding the components for the hydraulic hybridization. After that, the two vehicles is modelled and simulated using the AMESim code, and, finally, compared to each other in terms of energy savings