Simulations of two incineration processes, with and without flue gas recirculation, have been carried out performing also an exergy analysis, to investigate on the most critical equipment unit in terms of second-law efficiency. Flue gas from the economizer outlet is employed to partially replace secondary combustion air, to reduce, at the same time, incinerator temperature and oxygen concentration. Conversely, in the proposed configuration the recirculated flue gas flow rate is used to control incinerator temperature, while the air flow rate is used to control the oxygen content of the fumes leaving the incinerator to be as close to 6% as possible, i.e., the minimum allowed for existing plants to ensure completion of the combustion reactions, and determines the corresponding minimum flue gas flow rate. The flue gas recirculation guarantees a larger level of energy recovery (up to +3%) and, at the same time, lower investment costs for the lower flow rate of fumes actually emitted if compared to the plant configuration without flue gas recirulation. Various operating parameters were varied (incinerator's effluent gas superheating temperature, air flowrate, oxygen % in air flowrate, flue gas recirculation flowrate) to investigate on their influence on process exergy efficiency. Exergy analysis allowed to individuate the equipment units characterized by larger exergy destruction, i.e. water condenser (exergy efficiency=0.31) and incinerator (exergy efficiency=0.48), and demonstrated that the flue gas recirculation led to an overall process exergy effiiciency increase of about 2.5%. Basing on the obtained results, a further otpimization of the process was proposed substituting the water condenser with an air-condenser, obtaining an increase of the unit exergy efficiency of about 13%.

Longitudinal fins are one of the most common tools used to enhance the heat transfer from a given device or surface. There is a broad amount of literature related to this subject. Nevertheless, the analysis and design of convecting and convecting-radiating fins are still a topic of great interest in the research community. In this work, we consider a longitudinal fin of arbitrary profile with convective and radiation losses. The properties of the entropy production in this type of fins are analyzed. By taking advantage of the explicit expression for the distribution of heat along the fin, we investigate the possibility to assess the efficiency of these devices through the amount of entropy produced in the heat transfer process. The steady state is described by a second order, non-linear, one dimensional differential equation describing the distribution of heat along the longitudinal fin. We introduce an auxiliary dependent variable, solving a first order differential equation and related to the thickness of the fin, realated to the distribution of the heat. The purely convecting case, corresponding to a linear equation, and the convecting-radiating case, corresponding to a non-linear equation, are treated separately. The analysis of the efficienvy is performed both for purely convecting fins and for convectingradiating fins. A comparison with standard definitions of efficiency is given.

The paper aims to investigate ammonia/hydrogen premixed combustion in order to assist a high-efficient and low emission combustor design of a novel Linear Engine Generator. Characteristics of ammonia/hydrogen premixed combustion are revealed using a detailed chemical kinetics mechanism. An ammonia combustion mechanism is identified among many mechanisms and validated with published experimental data. In order to investigate the combustion characteristics under working conditions of the Linear Engine Generator with both internal and external combustor, a parametric analysis is carried out to study the effects of equivalence ratio (0.8-1.6), hydrogen blending ratio (0.0-0.6), initial temperature (300-700K) and initial pressure (1-20bar) on premixed laminar flame speed, ignition delay and concentrations of main pollutants. It is shown that an equivalence ratio of around 1.1-1.2 is beneficial to ammonia flame stability and cleaner emissions. Ignition delay is reduced and flame speed is enhanced with the increase of hydrogen blending ratio and initial temperature. However, excessive hydrogen blending (over 0.4) and ultra-high temperature result in the unburnt H2 and NH3 respectively, which would decrease the efficiency of combustion and the Linear Engine-Generator. It is also found that although high-pressure environment reduces the flame speed, ignition delay is shortened and NO emission is reduced considerably.

The aim of the research is to test the feasibility of a prototype of a newly designed thermal engine for a hybrid propulsion vehicle. The study consists of the implementation of an innovative supercharger for city car ICE (900cc). The preliminary proposal presented here is to mechanically disconnect the compressor/turbine device, supporting the rotation of the compressor with a dedicated electric motor and connecting a turbine to a generator. Mechanical decoupling will allow both machines to be designed for operating closer to their maximum performance point, for most of the expected real field of operation. Specifically, the turbine is likely to have a slightly lower rotation speed than the original group and will therefore be slightly larger in size. The advantage is that, while in the current supercharger groups the surplus at high regimes is discharged through the waste-gate valve without expanding in a turbine, in the configuration proposed all the energy of the combustible gases is used by the turbine to generate electrical power that can be used where required. Once the motorization of the vehicle (999 cc) has been fixed, the two turbomachines will have to be studied and designed, looking where possible, for commercial components. Finally, a CFD will be needed to verify the validity of the choice, followed by careful experimentation campaigns.

The motivation for this article was an effort to create an battery electric drive of a smaller excavator of a well-known manufacturer. This research followed the solution of the kinetic energy recovery of the road roller. The aim of the excavator electrification research was to replace its internal combustion engine with an electric motor so that the innovated excavator does not burden its surroundings with gas emissions and excessive sound emissions, so that it can work in confined spaces or protected areas. The solution was carried out in a number of stages– a patent search, the structure, functions, variants of individual solutions were analyzed, the technical possibilities of individual subsystems and the whole proposed electric drive system and the entire excavator with its mechanical and hydraulic systems were analyzed. The resulting variant included an accumulator, a Bodas RC control system, an electric motor control, a frequency converter, a special electric motor, etc. 3D models of drive elements were created to deal with the installation. Simulation models of electrical and hydraulic parts of the drive were created to select the most suitable solutions, which were verified or predicted by simulations in Matlab/Simulink environment. Tests have shown that the excavator is capable of operating for at least 7 hours without recharging the battery. The knowledge gained within the project will help in the electrification of other constructions, earthmoving and other machines, specifically the wheel loader, etc. In the development of the new electric battery drive of the excavator, mathematical modeling and simulations have proved to be a valuable tool. The main achieved results of the project are a functional model of a zero-emission mini-excavator with significantly reduced noise, a proven control algorithm in the form of software and its utility model according to the application 2018-35127 adopted by the Industrial Property Office of the Czech Republic. Innovation of the solution of the excavator was awarded the Gold Medal at the International Engineering Fair in Brno in 2018.

Like several other countries worldwide, the federal state of Belgium has decided on a phase-out of its nuclear reactor fleet. In Belgium these assets provide up to 40% of the total electrical energy production and generate the bulk of the baseload profile. With a phase-out timeframe of only five years, this presents the Belgian energy systems with sizeable challenges. The phase-out is especially challenging for industrial processes, for which a reliable and economic source of baseload power is paramount. In the light of ever more pressing environmental concerns, the carbon footprint of this energy source also has to be as low as possible.

In this paper we investigate the potential of generating baseload power in situ through cogeneration methods such as combined heat and power or gas turbine plants, in combination with renewable energy sources. Specifically, we look at clustering energy use and production on the level of an industrial business park or cluster considering both electrical and thermal energy.

First we discuss the potential for energy synergies on business clusters. In the Interreg 2 Seas project ‘Business clusters Integrated Sustainable Energy PackageS (BISEPS)’ we have catalogued the energy use of many industrial sites throughout Western-Europe. An overview of these results is presented.

Next we discuss the design and results of the Renewable Energy Area Collaboration Tool (REACT), which we have created to map and calculate potential energy synergies on the level of a business cluster. We show that the optimization potential of a combined energy use profile is most often larger than the gains that can be achieved by optimising individual profiles. This is especially true for heat production, which is traditionally generated with fossil fuel individually for each company on the cluster.

In the following step, we match the production profiles of renewable energy sources and cogeneration sources to the combined electrical and heat consumption profiles. We show that the carbon footprint of the business cluster can actually be reduced this way, while still providing the same level of reliability and affordability of the current situation.

In a final paragraph we take a look at the viability of partly replacing nuclear power with in situ cogeneration methods, and formulate policy recommendations to advance on this goal. With the relatively short lead time constructing these assets and their mitigating effect on the total carbon footprint, they might provide part of the solution for a nuclear phase-out in Belgium but also other countries.

The objective of thiswork is to analyze, through environmental vulnerability (EV), disturbances in the environment caused by anthropic activities for the production of energy resources, focusing on the power generation sector. Methodologically, hydrocarbons (oil and gas) and solar are considered through a qualitative and quantitative analysis of environmental impacts, including the research inside Environmental Impact Studies and procedures like EIA/RIMA (institutional Environmental Impact Reports in Brazil). This study focuses on operation and demobilization of offshore drilling activity, and installation and operation of the Santos Basin pre-salt oil and gas production and disposal activity Stages 1, 2 and 3. The criteria addressed in the EIA/RIMAs are used, focusing on thosethat correlate with EV and the production of electricity. Impacts for long-term, permanent, partially reversible or irreversible disturbances are filtered, totaling 53 impacts (31 effective/21 potential). We concluded that the criteria and methodologies of EIAs vary between stages. At times, the variation is so drastic that the same impact can have a completely different rating from one stage to another, despite referring to the same area. This condition makes it impossible to define a single vulnerabilityindex for the pre-salt venture. For a final analysis, we propose a cleaner energy production through distributed photovoltaic systems as a more adequate alternative for São Paulo’s energy supply in terms of its impact on EV.

Amongst the various alternatives for hot water production for domestic use, the instantaneous variety is still widely used in many markets such as the Portuguese market. In this, a gas boiler converts the chemical energy of the gas (LPG, NG) to a water stream, as it is used. The complexity of such devices range from those with a natural convection to those with fully pre-mixing of the air-fuel. The tightening of the legislation about these appliances is promoting an increase on efficiency, pollutant emission reduction and an increase on the safety features. One possible alternative is to couple the widely tested and low cost venture like partial pre-mixers with a ventilator and calibrated orifices to better control de air-fuel mixture over a wide range of operating loads.

The purpose of this work was to test the thermal performance of a water heater prototype with 22 kW of nominal heat output, running on Propane. Changes were been made to the plate with orifices that limit the air supply to the burner flutes, where the pre-mixture with the fuel is partially made. Four different plates with different orifice diameters were built and tested in real case scenarios, taking into special consideration the pollution emission and the fuel consumption verified.

The experiments were carried out using a gas analyzer and a data acquisition system to monitor and collect the information, in order to verify the compliance of the 26:2000 standard, with regard to the efficiency and carbon monoxide emission (CO). For each plate, working exclusively with the appliance fan, the installation characteristic curve in three distinct scenarios was traced: i) with primary air ducts blocked; ii) with secondary air duct blocked; iii) free airflow.

From the results it was concluded that the best configuration in terms of efficiency is the original one, followed by the “-0.5 mm” and “+1 mm” plates. On the other hand, the best plate in terms of CO emission was the “-1 mm” plate. Concerning the plates with diameters superior to the manufacturer’s original configuration, flame instability was verified as a result of the greater primary airflow. Under the same test conditions it was noted that the introduction of a nozzle into the fan inlet conducted to the suction of a larger amount of air. Finally it was also concluded that the reduction of the orifice diameters of the plates, reduces the split of primary air, resulting in an increased pressure drop in the flutes and on the global pressure drop of the system. These results were validated analytically by the dynamic balance method.

Renewable energy was responsible for more than a half in world capacity additions growth in 2017 and its share in total capacity increase will grow 46% until 2023, supporting an energy transition scenario [1],[2]. The employment of a technology that ensures a secure supply and expands renewables integration is a turning point in such a scenario. Energy Storage Systems (ESS), mainly batteries, may be the technology fundamental to bolster the growth of the renewables [3],[4], due to its services providing that may lead the deployment of the renewable, simultaneously ensuring the balance of the grid [3],[5].

Despite the strong confidence in the new role presented by ESS, there are still some concerns regarding business and legal barriers, and grid stability [4] [5]. To overcome uncertainties and foster storage implementation, it is fundamental to map risks and uncertainties and identify further benefits as parameters for an ESS implementation project. This work developed a framework to guide an ESS implementation into a timeline, separating the required actions into short, medium and long-term.

The required actions consider opportunities and risks regarding market orientation, society and populational changes, available technologies, political targets, and climatic agreements. The methodology labels these terms into barriers and opportunities, establishing working fronts and actions. As a result, it is expected a framework for an ESS insertion in Brazil.

[1] I. E. Agency, “Renewables 2018 market analysis and forecast from 2018 to 2023,” 2018.

[2] BloombergNEF, “Batteries boom enables world to get half of electricity from wind and solar by 2050,” 2018.

[3] Eurobat, “Battery Energy Storage in the EU” EUROBAT, 2016.

[4] I. Usera, P. Rodilla, S. Burger, I. Herrero, and C. Batlle, “The regulatory debate about energy storage systems: State of the art and open issues,” IEEE Power and Energy Magazine, vol. 15, no. 5, pp. 42–50, 2017.

[5] A. Gallo, J. Simões-Moreira, H. Costa, M. Santos, and E. M. dos Santos, “Energy storage in the energy transition context: A technology review,” Renewable and sustainable energy reviews, vol. 65, pp. 800–822, 2016.

The Solar Receiver is a critical component of concentrated solar power technology; it works as a heat exchanger, transforming the concentrated solar radiation into high-temperature heat. Volumetric receiver technology, using air as heat transfer fluid, are designed to reach higher temperatures than the current receiver technology, which is limited by material resistance and fluid instability. The higher temperature, up to 1200K, could be used in high-temperature industrial processes or a high-temperature thermodynamic cycle. A correct radiation propagation is essential to develop their performances, reducing reflection and emission losses and promoting the heat transfer to the fluid. In this study, the optical behaviour of Hierarchical Volumetric Receiver (HVR) developed in FBK has been studied using Monte-Carlo Ray Tracing (MCRT) simulations. The simulations have been validated in an experimental setup that evaluates the light transmissivity of the HVR porous structure. Two different HVR structures are evaluated with MCRT simulations that use a real solar dish geometry to configure a complete CSP plant. Results show that frontal and rear losses are, respectively, 12% and 3% of the incoming concentrated radiation. Inside the HVR, 15% of the incoming power is propagated trough the lateral void spaces. Therefore, the power spreading avoids the overconcentration of the centre of the focalized area. The HVR optical behaviour has been investigated, showing an optical efficiency of 85%.