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The thermal performance of a Parabolic Trough Solar Power Plant (PTSPP) is critical to the overall efficiency of the system. The advancement of this technologies has led to the development of steam production and efficient solution that utilizes the sun’s energy for thermal power generation. In this work a parabolic trough concentrator with aperture area of 10.8 m2 was designed and evaluated in the Research and Technology Center of Energy (CRTEn) in Tunisia. This type of concentrating solar power collector is analyzed for indirect steam generating system. Several parameters, as thermal characterization of absorber; thermal efficiency of mixed heat exchangers; thermal efficiency, concentration ratio and quantification of steam generation, were considered in order to study their effects on energy efficiency. Experimental results show that the receiver of parabolic trough concentrator extracts 552.73 W of absorbed energy. We found that the thermal energy efficiency varies from 24% to 28% for PTSPP system and reach an average concentration factor around 200. As results, the maximum value of the steam generated by parabolic trough concentrator is 8 kg/h.

The intensive energy requirements, the mismatch between the energy supply and demand and the nocturnal temperature drops are all crucial issues in the greenhouses solar heating. This paper seeks to evaluate the effect of a solar air heater with thermal latent storage on the greenhouse microclimate by pursuing the evolution of the internal climate before and after the heating. In this context, an experimental hydroponic greenhouse (HYDGR) and a solar air heater (SAHLSE) were realized in the Thermal Processes Laboratory in the Research and Technology Center of Energy of Borj Cedria in Tunisia. The solar heating with thermal energy storage enhanced the microclimate of the greenhouse and the temperature didn’t drop less than 32 and 15°C respectively the day and at night. The realized solar collector with thermal latent storage offered higher temperature even when the sun is unavailable and increased the internal temperature by more than 5°C. The studied solar system realized good improvement in the hydroponic greenhouse and appeared to be a beneficial alternative for ensuring optimal microclimate.

This paper deals with fractional multi-input, multi-output systems which guarantees a very small number of parameters that can reduce the computation time. It focuses in particular on the state-space representation of systems which highlights the state variables and allows to study the internal behavior with taking into account the initial state. It also discusses the discretization of this type of system to finally adapt the Robust Model Predictive Control (RMPC) to apply it and show its efficiency and performance in these systems.

In this paper, a new design to enhance the thermal performance of residential water heaters is suggested and investigated. The new design consists of using a mixer inside the water tank driven by electrical power. To proceed, experimental measurements are made by using thermocouples implemented in a water heater to study the thermal behavior. It is proved that the mixer could reduce the heating time about 20 min to heat water from 25 °C to 70 °C. In addition, the temperature homogeneity is also studied and it was shown that the temperature without the mixer could not be homogeneous within the water volume.

In recent years, net zero or plus-energy buildings (PEB) have been widely analyzed and discussed for their benefits of increasing energy savings and reducing greenhouse gas emissions. A successful transition to energy-efficient buildings must, however, develop an efficient method that examines technical, economic, environmental and social criteria. In this paper, a method for design optimization based on spatial analysis combined with multi-criteria decision-making was proposed for achieving plus-energy buildings in Algeria. To apply the proposed method, a single family residential building was chosen. First, the annual energy consumption of the building at 40 locations was evaluated and the results are then interpolated for the whole country. The best energy efficiency measures and renewable energy are then chosen using the Analytic Hierarchy Process (AHP) method. Finally, energy balance and spatial analysis were carried out based on the geographical information system. The results showed the energy plus target was achieved in large parts of the country using a high-performance envelope, more efficient appliances and solar energy (solar photovoltaic and thermal). In addition, the southern provinces, mainly Adrar, Tindouf, Bechar, Ouargla, and Illizi, have identified the most suitable areas for setting up new buildings with an energy-plus target. In addition, applying the method will reduce the overall energy demand by 43 % and reduce GHG emissions in the country by around 23 % by 2030. Therefore, the method will have a significant impact on sustainability locally and worldwide.

Organic devices based on pentacene thin film are demonstrated. Gold nanoparticles were used as the charge storage elements while pentacene has been used as the active semiconductor layer of Metal-Insulator-Semiconductor (MIS) structures. Polymethylmethacrylate (PMMA) formed the gate insulator. Four devices at different evaporation rates were fabricated and characterised by the atomic force microscopy and electrical characteristics. An optimal deposition rate was identified and supporting topographical images are presented. The device performance strongly correlates with the surface morphology, and the structural properties of the organic thin films have been investigated. The Atomic Force Microscopy (AFM) investigation of very slow evaporated pentacene showed larger grain sizes. Evaporating of gold electrodes on pentacene layers proved to change the morphology of the pentacene surface. The characteristics of bottom contact structures showed much-improved pentacene structures.

The work in this paper revolves fundamentally around the main axes of fuzzy control of the type Takagi-Sugeno (T-S) zero order for dynamic, complex nonlinear systems. In this paper, we present method for designing Fuzzy controller rule base using a new swarm intelligence algorithm, which is based on the Bat algorithm. The Bat algorithm is one of the most recent swarm intelligence based algorithms that simulates the intelligent hunting behavior of the bats found in nature. The main objective is to design the fuzzy rule base of fuzzy controller respecting the desired performance. To demonstrate the efficiency of the suggested approach, a control of a Magnetic Ball Suspension System is selected. Simulation results shows that the proposed approach could be employed as a simple and effective optimization method for achieving optimum determination of fuzzy rule base parameters.

Fiber reinforced composites pipes provide excellent strength and stiffness characteristics and high corrosion and erosion resistance. In addition, the possibility to tailor the strength and stiffness characteristics by optimizing the winding angle gives the designer extra flexibility to design different pipe based on the different working conditions. These properties make them attractive for several applications including lightweight and efficient equipment for energy production applications. In the current work, glass fiber reinforced plastic (GFRP) pipes were designed with four different winding angles. The pipes were tested under internal pressure and low velocity impact. Four different designs were manufactured using filament winding with winding angles of [±45/±45/±45], [±55/±55/±55], [±63/±63/±63], and [±63/±45/±55]. Each pipe has internal diameter of 110 mm, wall-thickness of 3.8 mm, and length of 450 mm. The pipes were exposed to internal pressure to determine their capacities and low velocity impact to assess their impact resistance. Under internal pressure, the maximum capacity was 56 bars and recorded for the pipes with [±55]3 winding angles. All specimens failed in the same way of initial leakage, governed by matrix cracking, which causes a drop in the internal pressure. For the impact resistance, the combined orientations ([±63/±45/±55]) showed higher assessment, compared to the other pipes. This higher damage resistance can be justified by the mismatch angle effect of the adjacent plies.

This paper proposes the Direct Torque Control (DTC) of a Wind Energy Conversion System (WECS) based on a Doubly Fed Induction Generator (DFIG) with power factor control strategy. The proposed technique aims at controlling the generator electromagnetic torque and rotor flux while controlling the power factor at the stator terminals. The proposed control is achieved through generating the referential electromagnetic torque from the Maximum Power Point Tracking (MPPT) control so that the maximum power is extracted for each different wind speed, and the referential rotor flux from the reactive power reference.

This paper proposes technical guidelines, modelling, and control of an ultra-high-speed-switched reluctance motor- generator for automotive turbo-charged assistance and energy recovery. Creation of an ideal model using electromagnetic finite element analysis and conducting a low cost/ low scale experiment is proposed. The first objective focuses on the transient simulation process. The second objective focuses on an investigation of the proposed control criteria. The modelling and analysis of a “Switched Reluctance Motor” (SRM) is an initial task for the selection of the coupled mover. Two controllers are selected for the experiment which consists of a generally low-cost solution and an optimized development board for prototyping optimization. The low-cost control solution is implemented with an Arduino Uno and an assortment of relays configured into an asymmetrical half bridge. The second controller is the “Digilent Zed Board Zynq-7000 ARM/FPGA SoC Development Board” (Zed board). ANSYS 2D, 3D modelling, data simulation for the stator and rotor are implemented. Current, voltage, and flux for all phases waveforms are included. Rotor dynamic simulation, machine transient simulations, and some other characteristics are depicted through 3D figures.

Numerical simulations using a two-fluid Eulerian model were performed for two-dimensional axisymmetric jets from a circular 20 mm diameter nozzle. The particle size vary between 30 and 180 μm and the particle charge ranges from 0.1 to 1. The modulations of the flow structures and the turbulent characteristics of the gas flow due to the solid particles with different sizes and rates of particle loading are studied. The jet spread and the decay of the mean center line velocity are calculated for all sizes and particle loading rates considered in this study. Additions of solid particles in the gas flow significantly modulate the turbulence of the gas in the nozzle as well as the flow rates. Fine particles suppress turbulence, while coarse particles improve turbulence.

In the study, an experimental investigation to the performance of the solar cells coupled with heat sink is presented. Indoor experimental setup was designed and assembled to investigate the impact of using heat sink cooling system on the performance of solar cells. Halogen lamps used to simulate the solar radiation and the study is carried out at different solar radiation values. Moreover, the study is carried out at natural and forced air to cool the heat sink. The results show that using heat sink cooling system enhances the performance of the solar cell. Temperature of solar cell decreased by about 5.4 % and 11 % by using heat sink cooling system at natural and forced air over the heat sink, respectively. Moreover, the efficiency and power of the solar cell system increase by about 16 % when heat sink cooling system is used.

It is vital in the prevention of the ferroresonance to consider this phenomenon from new side. The design of the equipment needs deep studies to avoid such disturbance. This paper presents a new way in ferroresonance studies, by the use of the Root Cause Analysis (RCA) in a systematic step by step process to discover the true cause of this problem. A fault tree is built to identify all possible causes leading to the unwanted top event, that is the False Trip Analysis (FTA). Among large statistics of disturbances, the probability of occurrence of ferroresonance is stated, and using the most studied causes of this event, the tree of analysis is built till reaching the main disturbance. In each step, well-known possible causes are shown. Then, a barrier or possible solution corresponding to the cause is presented. The new probability of occurrence is then calculated. The obtained result is compared to the initial probability and a set of protection system is proposed. The advantage of this study is the possibility to reduce the occurrence of the ferroresonance by gathering the maximum detailed amount of possible causes and by choosing the best barrier corresponding to the cause.

Over the past decades, meta-heuristic optimization techniques have become surprisingly very popular due to their flexibility and local optima avoidance capability. This paper uses the Whale Optimization Algorithm (WOA), a swarm-based technique to tune the Proportional-Integral (PI) based Maximum Power Point Tracking (MPPT) controllers of a grid-connected solar Photovoltaic (PV) system. The results of the PI-based Incremental Conductance (IC) MPPT technique are compared with both the conventional incremental conductance and the Perturb & Observe (P&O) MPPT techniques. Various modes of the PI controller are used. I, PI and Fractional order PI (FOPI) gain parameters are determined using WOA. Performance indices are applied to estimate the best parameters of the PI controller. This paper aims to show the effect of using PI-based MPPT controllers on enhancing the performance of a 400-kW grid-connected PV system. Simulation results show the capability of PI-based MPPT controllers on improving the performance of the PV system. It demonstrates the superiority of FOPI controllers over the other modes in enhancing system performance. The proposed work is simulated using MATLAB SIMULINK.

Achieving independence from fossil fuels and reducing emissions by increasing energy efficiency and utilizing green vehicles, such as hybrid electric vehicles and alternative green fuels, are among the main goals of energy policies globally. Although electric cars were introduced many years ago, agricultural electric vehicles have recently gained attention. Beyond emissions reductions, the benefits of agricultural electric vehicles include precise control, continuous variable speeds, and overload capability functionality. Moreover, such technology paves the way for the emergence of autonomous connected vehicles, which enhance work quality and increase operator comfort. Along with the electrification of agricultural vehicles, on-site production of renewable energy to supply their required power enhances the benefits in terms of increased efficiency and energy independence as a future-oriented approach. This paper outlines the trends in development and future perspectives of autonomous farm vehicles premised on green energies, with on-site energy production as a byproduct.

Wind is one of the most widely used non-conventional sources of energy. The majority of wind farms use a variable speed Wind Turbines Generator (WTGs) equipped with Doubly-Fed Induction Generator (DFIG) due to their advantages over other WTGs. The analysis of Wind Energy (WE) dynamics with the DFIG – Wind Turbines (WTs) has become an interesting research issue during transient faults. This paper investigates the effects of the different faults on transient stability. The analysis is performed on a 6-bus test system during transient faults and loss of excitation in synchronous generators. The stator-flux oriented vector control approach used for both stator and Rotor Side Converter (RSC) is proposed to mitigate DFIGs impacts on the system stability. The dynamic performance of DFIG variable speed WT under faults conditions are simulated using Neplan® program, considering different disturbance natures.

The constant research to eliminate wires in our everyday lives has been going on for years now. When the telephone or the telegraph was first invented, wires were needed to transmit communication between parties. Now, wireless power transfer is very beneficial for society. Wireless power transfer is already being implemented in today’s world in some cases, but it is not part of the "mainstream". Tesla had an ambition of transmitting wireless electricity to help the cause of not needing wires to be spread through the world. Thus, in 1891, he invented the Tesla-coil. The coil’s setup consisted of a primary coil with a capacitor and a secondary coil with a capacitor. Now, there is an essential need for expanding the utilization of wireless charging methods for electric vehicle technology to overcome the wired charging drawbacks and the cost. Various wireless power transfer (WPT) methods for electric vehicles charging are conferred in brief with some scientific examples and approaches. Inductive wireless power transfer prototype is experimentally implemented with 3D design is presented as well. Finally, some future points are mentioned in brief.

This paper aims to investigate the possibility of integration of Electric Vehicles EVs supply’s with electricity and/or hydrogen in the road transport sector and estimate the energy supply derived from solar irradiation by using solar roads technology. The case study is road Est-Oust (road E-O) of Algeria. A Geographic Information System and spatial analysis tools are combined with spatial data and technical models to carry out these calculations. The results of this study demonstrate that solar road panels, which are integrated into the road E-O, produce over to 804 GWh/year which equivalents to 13778 tons of hydrogen per year.by using FCEVs will saving over then 41.103 liter of fossil fuels (regular gasoline); and reduce GHG emission (CO2) in the transportation sector by 216 tons per year.

The classical diagnosis approaches, deeply spread in the industrial environment, are based on the Fourier analysis of the steady-state current, the basis of the proposed methodology consist of analysing the current demanded by the machine during the connection process (startup transient); the objective is to extract the characteristic evolution during the transient of some harmonic components created by the fault; this evolution is caused by the dependence of these components on the slip (s). In this paper the induction motor under dynamic and mixed eccentricity type is modeled with high precision using (CMC) approach.

Since the ambient temperature and solar irradiance are not constant, and the P-V characteristic curve of a photovoltaic (PV) module is nonlinear, it is hard for a photovoltaic system to operate at the maximum power point (MPP). In fact, using a maximum power point tracking algorithm (MPPT) to reach the MPP is significant when the climatic conditions change during the day. This paper presents a novel approach for grid-connected PV systems based on a Practical Swarm Optimization (PSO) metaheuristic algorithm to ensure the MPPT functionality as well as generating the reference power for the DC-Bus voltage regulation. The proposed method is compared with the conventional MPPT method Perturb and Observe (P&O) under different irradiance variations. The three-phase, two-level voltage source inverter (VSI) is controlled by a finite set model predictive controller (FS-MPC). The simulation results show that the proposed system is more efficient than the conventional method and has good dynamic performances.

This paper deals with site selection problems for hydrogen production plants and aims to propose a structural procedure for determining the most feasible sites. The study area is Adrar province, Algeria which has a promising wind potential. The methodology is mainly composed of two stages: the first stage is to evaluate and select the best locations for wind-powered hydrogen production using GIS and MCDM technique. the AHP is applied to weigh the criteria and compute a LSI to evaluate potential sites, and the second stage is applying different filtration constraints to select the suitable petrol stations for such hydrogen refueling station modification. The result map showed that the entire Adrar province is almost suitable for wind-powered hydrogen production with varying suitability index. The LSI model groups sites into three categories: High suitable areas, Medium suitable areas, and Low suitable. As a result, 2.95 % (12808.97 km2) of the study area has high suitability, 54.59 % (236320.16 km2) has medium suitability, 1.12 %(4842.94 km2) has low suitability and 41.34 % (178950.35 km2) of the study area is not suitable for wind hydrogen production. By applying the constraints, about 4 stations are suitable for wind-powered hydrogen refueling system retrofitting in Adrar province.

This article investigates the problem of state feedback stabilisation for discrete nonlinear singularly perturbed system with time-delay which is represented by a coupled multimodel. Based on an appropriate Lyapunov function, new sufficient conditions are given as a set of Linear Matrix Inequalities (LMIs) that are used to get the gains of controllers. Numerical example is given to illustrate the effectiveness of the proposed method.

The article presents a review about Maximum Power Point Tracking (MPPT) of PV system based cuckoo search algorithm. Cuckoo search (CS) provides several advantages such as the process of tuning parameters is few with high efficiency beside fast convergence. Cuckoo search uses a random walk according to le’vy flight in searching process. MPPT by using cuckoo search is compared to other two methods, neural network method which needs training for data and the incremental conductance method. DC-DC converter is utilized with direct duty cycle control of PWM based PID controller. The PID controller parameters are tuned using particle swarm optimization (PSO) and compared with classical methods. The results show that CS can track MPP under different operating conditions with lower power losses compared to the other two methods.

The aim of this paper is to present a command approach of a typical double-stage grid-connected PV system functioning under normal conditions and Symmetrical Grid Voltage Dips (SGVD). In Normal Operation Mode (NOM), the command developed rises the relatively low solar voltage to a suitable level corresponds to the Maximal Power Point Tracking (MPPT) and regulates, respectively, the dc-link voltage and the output inverter currents. It permits to inject energy into the grid at unity power factor and a current with low harmonic distortion. Under SGVD, the control strategy approach should ensure a stable connection as long as possible and inject some reactive power to support the grid faults. This command calculates dynamically active and reactive powers that inverter can deliver according to the level of voltage dips and inverter rating currents. Those values are used as reference to control output inverter currents, the dc-link voltage and to deactivate the MPPT command. To validate and to prove the effectiveness of the control strategy, some experimental results are also presented.

In this paper, three advanced modelling approaches will be performed to well describe the actual behavior of photovoltaic (PV) cells, in which some total solar irradiance changes are considered. The first one uses a specific solar cell provided by the Sim-Electronics tool of the Matlab software. It is used to simulate the actual behavior of PV cells instead of the conventional electrical circuit based on either single or double diodes. The second approach adopts some physical components provided by the Simscape library to reach the same above mentioned goal. The third approach uses the Simulink blocks to build the mathematical equations describing the PV cell behavior, in which some mathematical operators and functions are used. The three proposed models have the ability to predict the actual behavior of PV cells under different weather conditions. This can improve the extraction of the maximum power and contribute even to the synthesis of the appropriate controller. The performances assessment of each proposed model is established in term of the provided output power as well as the generated current and voltage.

Magneto-convection heat transfer mode inside a partially open-ended 2D enclosure, which is filled with conducting fluid, is considered as suitable research model in order to scope out our understanding into frequent decisive practicable applications in sustainable and renewable energy domains, especially solar energy collectors. Nevertheless surprising, continuously there is no existing literature dealing with it. Further, for Computational Fluid Dynamics (CFD)’s approaches, it is a considerable defiance to predict and anticipate this coupled complex physical engineering problem in MagnetoHydroDynamic (MHD) configurations. In the current numerical prototype, we introduce the lattice Boltzmann method (LBM) in the aim to overcome such engineering simulation difficulty. It is to be noted that this mesoscopic approach becomes nowadays an essential attractive and alternative for CFD approaches to simulate complex numerous fluid flow problems. ) has become an alternative and attractive approach to simulate numerous fluid flow problems. This paper intends to provide a brief review of researches on application of MHD convection with LBM on the prediction of thermodynamic behavior identifying more opportunities for future research. Besides, some new results are highlighted within this paper. To begin, the present LB model is validated against existing benchmark tests in literature. With the handout of this in house Fortran 90 LB code, we investigate the effects of Hartmann number, Rayleigh number, Prandtl number and the position of the partially open-ended side in the magneto-convective partially open ended y filled with conducting fluid cavity primly. It is established that these elements all impact flow and temperature fields patterns significantly. The obtained results can serve crucial theoretical prototypes for the related future practical magneto-convective applications. Our finding will be a useful tool allowing identifying opportunities for future research related to the considered engineering area.

A new method proposed in this work to optimize the power generated by a hybrid renewable energy system which consists of Wind turbine/Tidal turbine/PV module/Batteries. This system has been designed to satisfy a stand-alone area in Brittany, France, as an example of load demand. The Particle Swarm Optimization technique (PSO) was proposed and developed to minimize the cost of energy. Where the ability of this algorithm was developed to reach the best results in double speeds, at a time rate better than 80% of conventional technology time and less than 20 repetitions only. The problem is defined as an economic problem, taking into consideration the optimal sizing of the system, high reliability, planning expansion for future development, the state of charge of the battery. The total net present cost (TNPSC) is introduced as the objective function, taking into consideration the minimum fitness values in the particle swarm process. The (PSO) algorithm developed has several characteristics and advantages over other traditional techniques and algorithms. In fact, it allows to achieve the optimal solution and to reduce the overall cost with high speed and accuracy. The PSO algorithm program was developed using MATLAB software.

Three-D printed PLA (polylactid acid) was tested by means of differential scanning calorimetry after contact with commercially available organic phase change materials (PCMs) in order to be evaluated as an encapsulation or tank material in thermal storage systems. For a period of 40 days contact of 3D printed PLA specimens with two organic PCMs (A44 and A58) in liquid state, promising results were collected. In particular, insignificant mass uptake up to 0.012%/cm2 for the case of A44 and 0.045%/cm2 for A58 was observed. At the same time PLA crystallinity as calculated by differential scanning calorimetry data was found to improve over working time. These initial results therefore support the concept of structure on-demand encapsulation design by PLA 3D printing additive manufacturing of heat storage tanks for latent heat utilization of phase change materials.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) The global production of poultry is predicted to grow considerably in the future. Intensive poultry farming poses significant challenges to traditional waste disposal methods (i.e. direct land application) leading to environmental impacts. This paper discusses the result of low temperature (350-450 °C) pyrolysis of representative chicken litter as the feedstock. Four different feedstocks comprised of 50% organic chicken manure and 50% bedding materials (i.e. hay, straw, rice husk and wood shavings) have been experimentally investigated. The products of the pyrolysis process consist of char, gas and liquid (bio-oil). Maximum char production from the rice husk mix is over 67 wt.%, while the wood shavings mix feedstock resulted in the highest liquid yield of 44.4 wt.% at a temperature of 400 °C. Chicken litter and its char product are analysed by elemental analyser and bomb calorimetry. The composition of the evolved gases and bio-oil are analysed by micro gas chromatography (µ-GC) and gas chromatography-mass spectrometry (GC-MS), respectively. In addition, the mass and energy balance of the pyrolysis process are presented.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) The printed circuit heat exchanger is currently the preferred type of recuperative heat exchanger for the supercritical CO2 Brayton cycle due to its highly compact construction, high heat transfer coefficients and its ability to withstand high pressures and temperatures. This paper employs a three-dimensional numerical model to investigate the thermohydraulic performance of supercritical CO2 flow in a printed circuit heat exchanger. This numerical model considers entrance effects, conjugate heat transfer, real gas thermophysical properties and buoyancy effects. The inlet temperature and pressure are 100 °C/150 bar on the cold side and 400 °C/75 bar on the hot side while the mass flux is varied from 254.6 to 1273.2 kg/(m 2 ·s). The overall performance of the heat exchanger and comparisons of local heat transfer and friction pressure drop with predictions from the empirical correlations are presented and discussed. Overall, this paper provides useful information that can be employed in the design of recuperators for supercritical CO2 Brayton cycle applications. Research Councils UK Centre, EPSRC project and European Union’s Horizon 2020 research and innovation programme

Characterising rehydration kinetics is key to understand the effect of microstructure on the quality of rehydrated products. Well-connected porous networks, like the ones created by freeze-drying processes, can enhance water absorption and transport, leading to higher final quality rehydrated products. Such products present the basis for a novel distribution scenario for (freeze-)dried products that are rehydrated closer to the consumption point. In this work, fresh tomatoes were first freeze-dried and subsequently rehydrated at different temperatures. Four rehydration models were fitted to the experimental data using regression analysis. The goodness-of-fit was evaluated according to (i) Root Mean Squared Error (ii) adjusted R-square (iii) Akaike Information Criterion (iv) Bayesian Information Criterion. The Exponential and Weibull models provided the most accurate descriptions of the rehydration kinetics. The effect of temperature on rehydration kinetics was also evaluated, with rehydration capacities and equilibrium moisture contents of the rehydrated tomatoes increasing with temperature. In addition, activation energy values for rehydration, which were in accordance with the existing literature values, were also obtained from the fitted rehydration rate parameters.

The human relationship with food is an under-acknowledged contributor towards climate change and environmental degradation. However, citizens’ choices and actions regarding food consumption and production in urban settings are shaped by the economic, cultural and infrastructure systems in which they live. The purpose of this paper is to examine, from the perspective of prosumers, the socio-technical factors that affect urban food production and associated energy, water and waste services. A residential development on the urban fringe of Australia’s subtropical Gold Coast was used as a case study. A mixed methods approach was utilised to gather quantitative and qualitative data through estate maps, development planning documents, visual observations, interviews and surveys. Data was analysed around the themes of food production, consumption and development infrastructure (physical and social). The estate’s food production demonstrated high biodiversity and highlighted three common challenges: biological, knowledge and water/climate. Food consumption incorporated self-consumption, sharing/trading and a range of other typical and atypical sources found in cities. An integrated approach to land-use, energy, water and waste was instrumental in enabling food production, highlighting issues that affect the ability of urban prosumers to incorporate sustainability into their food practices. The paper raises the possibility of a ‘sharing-economy’ food production typology for urban areas and proposes an initial performance indicator framework (people, planet, prosperity, governance and propagation) to understand, develop and manage urban prosumers in the context of integrated energy, water, waste and food services.

Most food products are currently processed in large, centralised factories with delocalised retail systems, which allows food processors benefit from economies of scale. This is efficient in terms of production, but can involve lengthy and rigid supply chains, with higher transport costs and environmental impacts. Decentralised manufacturing, based on local production at small scale, has risen recently as an alternative that could provide flexibility to the food supply chain. In this work we present a modelling tool for the design, evaluation and comparison of food manufacturing processes that considers economic, environmental and social factors. The proposed method can be applied to a wide range of food products and is illustrated here using cereal porridge and sandwich bread production. We have assessed and compared three decentralised scenarios: “Home Manufacturing” (HM), “Food Incubator” (FI) and “Distributed Manufacturing” (DM) to centralised production –i.e. Single Plant (SP) and Multi Plant (MP) scenarios. Based on UK demand, SP is the most energy efficient and cheapest scenario in both cases, closely followed by HM and FI in cereal porridge production. DM could compete with SP assuming low management costs and savings on transportation/storage along the supply chain. For the case study on bread, the shorter margin of profit per unit makes decentralised scenarios less advantageous.

The purpose of this paper (parts I and II) is to examine the socio-technical factors that affect urban food production and associated energy, water and waste services. Part I introduced the growing role of prosumers, discussed the context of the human relationship with food and demonstrated how citizens’ choices and actions regarding food consumption and production in urban settings are shaped by the economic, cultural and infrastructure systems in which they live. A residential estate on the urban fringe of Australia’s subtropical Gold Coast was described, setting the context for a mixed methods analysis of quantitative and qualitative data gathered through estate maps, development planning documents, visual observations, interviews and surveys. Part II presents the results, analysed around the themes of food production, consumption and development infrastructure (physical and social). An integrated approach to land-use, energy, water and waste was instrumental in enabling ubiquitous high biodiversity food production, highlighting planning decisions that affect the ability of urban prosumers to incorporate sustainability into their food practices. The case study demonstrates that an integrated approach to urban infrastructure can support and enable urban prosumer food practices. A framework to evaluate urban neighbourhoods in terms of potential for creating synergies between land use, water, waste and energy infrastructure is presented and an initial performance indicator framework is proposed, to understand, develop and manage prosumer-driven urban agriculture in the context of integrated energy, water, waste and food services.

peer-reviewed A pilot scale investigation of co-pyrolysis of biological dairy sludge and spruce wood chips and pyrolysis of spruce wood chips solely was carried out. Pyrolysis was tested as a waste treatment method aiming to reduce the volume of dairy sludge while producing a pyrolysis gas suitable for an internal combustion engine. Pyrolysis tests were carried out in a continuously fed, pilot scale rotating retort type of facility in the temperature range between 700 and 770 °C. Feedstock feeding rates were between 40.9 – 68.6 kgd.a.f. h-1. Tar yields and composition was measured by means of the solid phase adsorption method in order to assess gas quality with regard to the specified tar limits given for downstream applications. The yields of total gas chromatography detectable tar produced from the dairy sludge and spruce wood chips blend was in the range between 7.25 - 10.98 gtotal tar Nm-3 dry raw gas, while spruce wood chips solely produced yields between 11.18 - 13.31 gtotal tar Nm-3 dry raw gas. Composition wise, the main difference was a number of nitrogen-containing tar compounds reflecting the high nitrogen content in dairy sludge feedstock with 2-butenenitrile, pyridine and 1H-pyrrole being the most abundant nitrogen-containing tar compounds. Raw pyrolysis gas from the two feedstocks tested did not meet the requirements regarding tar limits given in the manufacturer’s specification for their internal combustion engine. The raw pyrolysis gas contained excessive amounts of 3 and 4+ aromatic ring tars. Therefore tar removal is required prior to combustion in the engine. The proposed tar removal strategy includes a thermal tar reformer using air as a reforming agent followed by adsorption using wood chips, or in-process generated bio-char, or torrefied biomass as a viable adsorbent.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) An approach considered in recent years to improve the efficiency of open-type refrigerated display cabinets is to install air guiding strips at the front face of the shelves with a single layer air curtain. This paper presents experimental results comparing a conventional open-type vertical refrigerated cabinet and a cold shelf innovation, which integrates both air-guiding strips and air supply at the front of individual shelves. In addition, a comprehensive and detailed Computational Fluid Dynamics model using ANSYS Fluent has been created to further investigate the influence of the cold shelve innovation on the performance of vertical multi-deck refrigerated display cabinets. The experimental results showed energy savings of 16.7 kWh/24 hrs for the guiding strips and cold shelf innovation compared to the conventional cabinet due to the more efficient air curtain and lower air temperature entering the evaporator coil. Research Councils UK Energy programme

The Paris Agreement aims to combat climate change by keeping a global temperature rise this century well below 2oC by the reduction of CO2 production. Scotland aims to be a world leader in the change and has set ambitious targets to meet this commitment. With nearly 70% of the energy cost in the production of ice cream spent on refrigeration, any improvement in their efficiency will reduce energy costs and CO2 production. A waste heat recovery system presents a great opportunity to reclaim energy from the onsite refrigeration systems and convert it into useful hot water. A £216,275 project funded by The Engineering and Physical Sciences Research Council and Innovate UK was setup to investigate the use of a waste recovery system within an onsite refrigeration system. The results showed a savings of 5% by the refrigeration plant in total along with an individual saving of 27% by the compressor within the refrigeration system. The WHRS also produced a supply of hot water which could be used onsite within the manufacturing or cleaning processes required onsite.

Instant coffee manufacture involves the aqueous extraction of soluble coffee components followed by drying to form a soluble powder. A challenge that arises from the process is the loss of volatile aroma compounds during evaporative drying. One method of retaining aroma is to first steam strip the volatiles from the coffee and add them back to a concentrated coffee solution just before the final drying stage. Understanding the impact of process conditions on the aroma content of the stripped solution offers engineers the ability to target desirable compounds and maximise their yield. This paper presents a multiscale model for aroma extraction that describes: (i) release from the matrix, (ii) diffusion through the coffee grain, (iii) transfer into water and steam, and (iv) advection through the stripping column. Results reveal how aroma physiochemistry determines the limiting kinetics at industrial extraction conditions. The interaction with the soluble matrix can also inhibit extraction, but this effect varies for the different aromas studied.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) The overall heat transfer coefficient of two CO2 gas coolers was investigated through experiment and Computational Fluid Dynamics (CFD). The CFD modelling provided prediction accuracy for the overall heat transfer coefficient with a maximum error of 9% compared to the CFD predictions. Comparing the two gas cooler designs, and from the experimental and modelling results it has been shown that the performance of the gas cooler can be improved by up to 20% through optimization of the circuit design of the gas cooler. A horizontal slit between the 1 st and 2 nd row of tubes of the gas cooler can increase the overall heat transfer coefficient by 8% compared with the a fin without the slit. DRPM RISTEK DIKTI and RCUK

In food processing, insufficient cleaning can result in reduced efficiency, contamination in final product, and energy losses. To optimise widely implemented clean-in-place (CIP) systems, it is critical to understand the influence of the interactions between surfaces, foulant, and chemical agents on the efficiency of the cleaning process. The present work investigates the effect of wall temperature and surface roughness on the surface free energy of stainless steel 316L coupons. Equilibrium contact angles (ECA) of four commonly used liquids, namely ethylene glycol, 1-bromonaphathalene, water, and diiodomethane were measured on the surfaces of interest. Finally, ECAs of liquids were used to quantify surface free energy (SFE) of the solid substrate. Our results show that surface energy is proportional to the roughness and well-prediction of liquids wettability as a function of roughness and temperature. It demonstrates the importance of surface characteristics in determining interfacial energy, and consequently the efficiency of CIP for food engineering.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This paper focuses on predicting centrifugal compressor performance in the supercritical region of real gas. For this purpose, thermodynamic changes have been considered in the sub-regions of the supercritical space. It is known that some properties (e.g. compressibility or density) of supercritical fluids behave anomalously in a narrow temperature-pressure band, shaped by pseudocritical lines, which start at the critical point and extend to higher T and P values. To accurately predict the performance of supercritical carbon dioxide (sCO2) turbomachinery, the fluid behavior, in three regions (liquid-like, pseudocritical and vapour-like) created by pseudocritical lines, should be considered. For this purpose, computational fluid dynamics (CFD) is employed to calculate compressor performance in different regions of the supercritical space. The selected compressor geometry is the compressor impeller tested in the Sandia sCO2 compression loop facility. The results illustrate that operating points in the liquid-like region achieve the highest pressure rise. In addition, fluctuations in two fluid properties, density and speed of sound, have been observed wherever their pseudocritical lines have been crossed. However, the reason for these variations needs more investigation. The study considers the sudden changes occurring in the supercritical region and should lead to more accurate prediction of compressor performance,. European Union’s Horizon 2020 research and innovation programme under grant agreement

Nowadays, all industry, including the agri-food sector, faces the urgent need to increase its competitiveness in order to survive in a global market. In this context, it is vital to ensure a strong, renewed and innovative industrial base throughout all stages of the value chain, capable of competing internationally and differentiating itself by the quality of its products and services. Since wealth generation cannot be dissociated from productivity, which in turn is closely related to the trinomial: processes, technologies and quality, it is concluded that the implementation of this strategy requires a commitment to the qualification of organizational management, operational management, project management and processes and productive systems themselves and associated technologies. This paper presents the characterization of the energy consumption and technologies in bakery and pastry sector, one of the most significant in the Portuguese agri-food sector.

Food and drink processing industries are extremely large consumers of thermal energy as well as bio-wastes producers. The utilisation of bio-wastes for energy recovery appears to be a good opportunity to improve the overall efficiency of process industries. In this study, waste generation, management and energy auditing of a micro-brewery located in the north east of England is investigated. Fermented grains and hops are disposed as organic wastes after the production process. Hence, this study focuses on recovery of energy from these wastes through anaerobic digestion process. Experimental work was carried out in the laboratory for the wastes characterisation. The waste samples are then anaerobically digested at 55 ⁰C and 35 ⁰C with a 5L laboratory scale continuous stirred reactor using 5 gVSL-1 and 25 days organic loading rates and hydraulic retention times respectively. Further to the experimental work, simulations were completed to evaluate the feasibility of the process. ASPEN plus simulation software was used to carry out the simulations using a novel approach for AD which is based on the ADM1 model. The experimental results showed that biogas can be produced at mesophilic and thermophilic conditions: 3.0 and 2.6 litres per day respectively. At thermophilic conditions, the methane content is 65 % while at mesophilic conditions, it is 55%. It is also found that the values of the final biogas production from the simulation were similar to the ones obtained in the experiments (-6.85%). However, the model would need further modifications to be able to accurately predict the biogas compositions. The result shows that the thermophilic process is able to fuel 126.01 kW boiler while mesophilic process can power 76.48kW boiler.

Predicting the electricity demand of new supermarkets will help with design, planning, and future energy management. Instead of creating complex site-specific thermal engineering models, simplified statistical energy prediction models as we propose can be useful to energy managers. We have designed and implemented a data-driven method to predict the ‘electricity daily load profile’ (EDLP) for new stores. Our preliminary work exploits a data-set of hourly electricity meter readings for 196 UK supermarkets from 2012 to 2015. Our method combines the most similar stores on a feature space (floor area split by usage such as general merchandise, food retail and offices and geographical location) to obtain a prediction of the EDLP of a new store. Computational experiments were performed separately for subsets of supermarkets that consume only electricity, both electricity and gas, and by season. The best results were obtained when predicting Summer EDLPs with stores using electricity only. In this case, the average Manhattan difference and the percentage difference are 234 kWh and 16%, respectively. We aim to develop an application tool for supermarket energy managers to automatically generate EDLP for potential new stores. EPSRC Impact Acceleration Account - University of Oxford EP/R511742/1

The Circular Economy is an economic and industrial system in which resources are used for as long as possible. This typically involves businesses implementing a range of alternative business models, such as remanufacture. With the manufacture of Refrigerated Display Cabinets (RDCs) being a material and energy intensive process, there is scope for remanufacturing to support a more resource-efficient production of RDCs. Despite the potential, the remanufacture of RDCs in the UK is uncommon. Many Retailers and RDC Manufacturers typically have unfavourable attitudes towards the purchase and production of remanufactured RDCs. However, more favourable attitudes could increase their Behavioural Intentions towards the purchase and production of remanufactured RDCs, which could lead to the adoption of remanufacturing across the industry. This paper gives an overview of interventions that could be implemented to encourage Retailers and RDC Manufacturers to adopt the pro-circular behaviours. The three interventions discussed in this paper are: Financial Incentives, Quality Standards and Process-Supporting tools.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Surface processing of the materials used for the heat exchanging surfaces in condensing economizers and related facilities are used to deliver coatings to protect them from the corrosive condensates. By delivering increased corrosion protection, intact thermal conductivity, along with robust mechanical and wear resistance characteristics at low process costs, the lifetime of the investment is increased and the service periods become longer. However, during the past years surface processing has provided tools towards solutions for additional favorable surface features related to wetting phenomena. Coatings to enhance the dropwise condensation over the film-wise condensation, to increase the condensate collection rate and to promote the self-jumping of the condensates are far from rare. These features have a tremendous effect on the heat transfer coefficient and hence on the thermal efficiency of related heat exchange applications. Still, such features are typically not included on the testing protocols for the coatings being developed or demonstrated and they are not among the standard engineering selection criteria. In this work we briefly describe these features and provide preliminary equations for design and evaluation of their importance on the heat transfer coefficient. European Union’s Horizon 2020 research and innovation programme

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This research aims to investigate development of corn-oil ester and water mixtures as novel solid-liquid phase change material candidates for chilled and frozen food refrigeration applications. Thermal properties of both water and its mixture with corn-oil ester were tested by DSC and T-history methods. The results showed that corn oil could mix well in water solutions. Phase transition temperatures of the mixtures were lower than those of individual water. Corn-oil ester in the mixtures was acted as a nucleate agent and it was able to lower freezing point and to trigger ice nucleation in water which could diminish super-cooling. Addition of corn oil ester by 5% to 35% in water solutions could decrease freezing temperature from 0°C down to respectively -3.5°C to -28°C. The PCM candidates were also found to have excellent thermal properties that could fulfill requirements of thermal energy storage systems for food refrigeration applications. Higher Education Directorate General of the Ministry of Education and Culture of the Republic of Indonesia

This study evaluates the life cycle environmental sustainability of cheddar cheese with energy recovery from cheese whey via anaerobic digestion. Environmental hotspots and improvement opportunities along the supply chain are also identified. The cheddar cheese production process has been simulated by using Aspen Plus. The environmental impacts have been estimated through life cycle assessment (LCA) using the outputs from process simulation. The LCA data for the rest of the life cycle have been sourced from databases and literature. The results reveal that the total primary energy consumed in the whole life cycle of cheddar cheese is 347 MJ, with the carbon footprint equal to 14 kg CO 2 eq. per kg of cheddar. Energy recovered from anaerobic digestion of whey reduces the total life cycle primary energy demand and the carbon footprint by only 2%. Much greater reductions could be achieved by targeting milk production and storage of cheese. However, anaerobic digestion of whey makes the cheese production process energy self-sufficient and reduces the production costs. It also makes the production process carbon negative, reducing its carbon footprint from 0.12 to -0.12 kg CO 2 eq./kg due to the credits for electricity and heat produced from biogas.

This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Reducing food waste and increasing resource efficiency have become worldwide targets as highlighted by the United Nations Sustainable Development Goal 12 - Responsible consumption and production. Food packaging, in particular plastics-based, is a key component of food-related waste: packaging increases the amount of total waste, but also reduces potential food waste by protecting food products and prolonging their shelf life. Therefore, it is important that packaging is designed as to satisfy both technical and environmental criteria. Hence, this paper seeks to develop a decision-support framework and key metrics to aid development and selection of new innovative food packaging within a circular economy context. A set of indicators is proposed, integrating techno-environmental and circular economy criteria to help designers as well as food and packaging manufacturers develop more sustainable products. The methodology is illustrated through a prototype new plastic packaging developed as part of this project, considering its use for two types of product - raspberries and meat - as illustrative examples. UK Research Councils

Current environmental policies, which promote a more sustainable food sector, have boosted efforts to reduce energy demand during processing, and particularly during drying operations. One of the routes towards more sustainable and efficient drying processes is the design and implementation of optimal operational routines for the existing drying equipment. In the food industry, drum-dryers are typically employed for the production of food powders from viscous slurries (e.g. starchy slurries). Food powders are used in a wide range of applications in the food industry, from beverage powders (milk or cocoa), instant soups, spices or flours and flavours. In this framework, we propose a model-based optimisation routine for the operation of a double drum-dryer (product under atmospheric conditions) used in the manufacture of a breakfast cereal porridge. The problem defines optimal steam temperature and optimal rotation speed that minimises the energy demand of the dryer operation for a range of operating conditions that considered different: product formulation, final moisture contents, thickness and initial temperature of the wet slurry. Overall, this work demonstrates the potential of model-based approaches to the design and optimisation of more sustainable and efficient industrial drying technologies in the food sector, which can help in the achievement of short/medium-term energy reduction goals.