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Thermal energy management in the bread baking industry using a system modelling approach
Abstract
Energy usage in bread ovens is analysed using a generic methodology applicable to all types of mass-production tunnel ovens. The presented methodology quantifies the energy required to bake the dough, and to conduct a detailed analysis of the breakdown of losses from the oven. In addition, a computational fluid dynamics (CFD) optimisation study is undertaken, resulting in improved operating conditions for bread baking with reduced energy usage and baking time. Overall, by combining the two approaches, the analyses suggest that bake time can be reduced by up to 10% and the specific energy required to bake each loaf by approximately 2%. For UK industry, these savings equate to more than £0.5 million cost and carbon reduction of more than 5000 tonnes CO2 per year.
... Among all the stages (ingredients selection, mixing, storage/dosing, baking, cooling, packing, storage, distribution, and commercialization) involved in the bakery industry, the baking process is the most crucial stage. The energy requirement at this stage is reportedly between 0.5 and 7.3 MJ kg −1 [2][3][4]. This large variation mainly depends on different factors such as type of products, mass of the products, source of energy and type of oven [2]. ...
... A significantly greater emphasis is being placed on the need for more efficient baking techniques due to rising energy costs and changing legislation [9]. Some previous studies have been worked on CFD modelling for commercial ovens, to describe the thermal behaviour of the system and energy efficiency of the oven [1,3,9,10]. Papasidero et al. [11] analysed the energy consumed by bread and optimized the system, in a batch and different energy sources, without the intervention of mechanical parts and designs of the equipment. ...
... Nicolas et al. [27] investigated the bread energy consumption by multiphase model as 200 kJ (61 kJ kg −1 ). Other researchers focused on estimation of energy requirement by Paton et al. [3] for dough cooking (222 kJ kg −1 ), moisture evaporation (242 kJ kg −1 ), and starch gelatinization (12 kJ kg −1 ) during baking process. Similarly, Ploteau et al. [45] estimated energy demand for complete transformation of bread dough into end product during cooking process. ...
Inverse heat transfer is a more efficient method for estimating unknown quantities of variable interest. The aim of present research work is to successfully predict the energy consumption to bake the bread at different baking oven temperatures during baking processes using the inverse heat transfer method. This inverse technique allows researchers to avoid the usage of intricate and expensive instrumentation. This study also compared different numerical techniques for estimating accurate sensitivity coefficients. The inverse heat transfer problem is presented as a multi-parameter estimation of heat flux and solved by the Levenberg–Marquardt algorithm. The finite element method is applied to solve the transient standard heat transfer problem while considering nonlinear two-dimensional heat transfer. The results demonstrated that the complex variable differentiation method was given the satisfactory results than the forward difference method and central difference approximation method. In order to demonstrate the accuracy of the results, statistical analysis is performed for estimated parameters. A good agreement of results is obtained with help of the inverse heat transfer problem. This developed model provides the information to enable the energy required to cook any food product in food thermal processing accurately.
... Baked products are a staple food worldwide. They are essential for human nutrition (Paton et al., 2013;Cappelli et al., 2020b) as they are an important source of carbohydrates, protein, dietary fiber, vitamins, micronutrients, and antioxidants (Cappelli et al., 2020b;Bredariol et al., 2020). Bread, in particular, is one of the oldest types of baked goods (Raheem et al., 2019). ...
... The air temperature profile inside an industrial continuous indirect-fired oven takes the form of a bell-shaped curve along its length (from the entrance to the end), while wall temperatures vary linearly. A baffle plate geometry could exert an important hydrodynamic influence in the reduction of pre-heating time (Arepally et al., 2020;Paton, 2013). ...
... Several types of ovens are used. Industrial ovens are typically gas powered, and usually classified as direct (forced convection), indirect, microwave, radiation, or IR systems (Paton et al., 2013). Other energy sources include oil, electricity, and woodchip burners. ...
Background
The quality of bread and bakery products is mostly influenced by the three key stages in the production chain: milling, kneading, and baking. The effects of milling and kneading have been systematically reviewed in earlier work, however, there is no comprehensive review of current knowledge regarding the baking process, its effect on product quality, and improvement strategies. The present study addresses this gap.
Scope and approach
The first aim is to summarize current knowledge regarding baking technology, and its effects on the characteristics of bread and bakery products. The second aim is to suggest strategies to improve baking and ovens, increasing efficacy, efficiency, and the quality of the final product, with positive impacts on production, profitability, and the environment.
Key findings and conclusions
This review highlights the importance of selecting the optimal baking technique as a function of the desired product characteristics. Conventional ovens could be improved through a combination of steam and vacuum techniques. Microwave ovens could be significantly improved by hybridization with other techniques such as IR and IR-visible heating, which combine the browning advantages of IR with the time-saving advantages of microwaves. Both of these hybridizations would reduce baking time, energy consumption, and environmental impacts. In conclusion, despite the great strides that have been made, there is a need for totally new baking methods and ovens that are able to efficiently use renewable energy sources, if we are to face the monumental challenge of environmental sustainability.
... Authors proposed a mechanistic heat and mass transfer model, which was able to estimate product energy demand and the potential energy savings. Paton et al. [7] analysed the energy requirements in a continuous industrial oven using a macroscopic balance and proposed a CFD scheme to study the influence of the operative conditions. In addition, Khatir et al. [1] combined the CFD model of the oven with a multi-objective optimization methodology to develop an oven design tool. ...
... Usually, there can be found in the literature many mathematical models that describe the baking process in terms of energy conservation laws [15,16]; only a few of them have the intrinsic capacity to predict the product energy demand [1,7]. ...
... Other researchers focused in this issue using a similar method to calculate energy demand particularly for bread baking. In this sense, Paton et al. [7] informed similar values considering the energy demand for heating the dough, the energy to evaporate around 10% of the initial moisture content and the energy required for starch gelatinization. Also, Ploteau et al. [8] estimated a similar energy demand taking into account the main transformation that occurs during baking (dough into crumb and crust) and water evaporation. ...
Baking is a high energy demanding process, which requires special attention in order to know and improve its efficiency. In this work, energy consumption associated to sponge cake baking is investigated. A wide range of operative conditions (two ovens, three convection modes, three oven temperatures) were compared. Experimental oven energy consumption was estimated taking into account the heating resistances power and a usage factor. Product energy demand was estimated from both experimental and modeling approaches considering sensible and latent heat. Oven energy consumption results showed that high oven temperature and forced convection mode favours energy savings. Regarding product energy demand, forced convection produced faster and higher weight loss inducing a higher energy demand. Besides, this parameter was satisfactorily estimated by the baking model applied, with an average error between experimental and simulated values in a range of 8.0 to 10.1 %. Finally, the energy efficiency results indicated that it increased linearly with the effective oven temperature and that the greatest efficiency corresponded to the forced convection mode.
... The worldwide commercial bread baking sector is a hugely significant manufacturing industry, with over 94 million tonnes of bread consumed each year [1]. The baking process is of major environmental importance as it is the most energy intensive process in the bread manufacturing cycle, consuming an estimated 804 kJ per kg of bread [2], and ultimately determines many of the final physical properties of bread, such as crust colour, crumb texture and taste [3]. ...
... Traditionally, energy efficiency has not been the main goal in oven design with other features such as ease and reliability of operation, access for cleaning, costs of maintenance, consistency of production and ability to cope with high production rates being of greater importance. This has resulted in typical commercial bread ovens having efficiencies of less than 50% [2,4]. Higher energy prices and the increasing importance of environmental sustainability and corporate responsibility have led to much greater incentives to reduce energy consumption within industrial ovens [5] as required by the European Energy Efficiency Directive [6]. ...
... The combination of the air speed and temperature enables the electrical energy (fans) and heat energy (gas) consumption to be estimated. (2) An overview of the proposed optimisation methodology is given in Figure 3. The parameter K(H/d,f) in equation (2) is determined experimentally and enables h c to be predicted as a function of the three design variables. ...
In response to increasing energy costs and legislative requirements energy efficient high-speed air impingement jet baking systems are now being developed. In this paper, a multi-objective optimisation framework for oven designs is presented which uses experimentally verified heat transfer correlations and high fidelity Computational Fluid Dynamics (CFD) analyses to identify optimal combinations of design features which maximise desirable characteristics such as temperature uniformity in the oven and overall energy efficiency of baking. A surrogate-assisted multi-objective optimisation framework is proposed and used to explore a range of practical oven designs, providing information on overall temperature uniformity within the oven together with ensuing energy usage and potential savings.
... Half of the energy use in a bakery is in the oven [2,3], with other significant contributors including mixers, provers and coolers. Of the thermal energy supplied to the oven, waste heat accounts for 46% of the total heat supplied [4,5]. Reducing this proportion of waste heat is of paramount importance to bakeries and oven manufacturers for both economic and environmental reasons. ...
... This can then be experimentally verified and can be used to drive oven design for energy savings. Previous studies [4,9,15] have shown how quality assessments can be made based on temperature uniformity inside the oven allowing the CFD model and the baking model (predicting bake time) to be decoupled. Temperature uniformity can be further confirmed by the CFD results laid out in Section 3.3. ...
... The thermal energy efficiency saving can be calculated by assuming that approximately 19% of oven heat is lost to ambient, using the methodology described in detail by Paton et al. [4,5]. Therefore for a faster bake time the specific energy loss (kJ of energy per kg of product produced) is reduced linearly with bake time. ...
Changing legislation and rising energy costs are bringing the need for efficient baking processes into much sharper focus. High-speed air impingement bread-baking ovens are complex systems using air flow to transfer heat to the product. In this paper, computational fluid dynamics (CFD) is combined with experimental analysis to develop a rigorous scientific framework for the rapid generation of forced convection oven designs. A design parameterisation of a three-dimensional generic oven model is carried out for a wide range of oven sizes and flow conditions to optimise desirable features such as temperature uniformity throughout the oven, energy efficiency and manufacturability. Coupled with the computational model, a series of experiments measuring the local convective heat transfer coefficient (hc) are undertaken. The facility used for the heat transfer experiments is representative of a scaled-down production oven where the air temperature and velocity as well as important physical constraints such as nozzle dimensions and nozzle-to-surface distance can be varied. An efficient energy model is developed using a CFD analysis calibrated using experimentally determined inputs. Results from a range of oven designs are presented together with ensuing energy usage and savings.
... For other types of bread, several optimization strategies were carried out to select the best kneading, leavening or baking parameters. These optimizations employed an extensive mathematical modeling, genetic algorithms or ANN [34][35][36][37][38][39]. Therefore, to the wealth of the Carasau bread manufacturing process, the industrial bread production must be supplied with an ICT, cost-effective tool capable of allowing a real-time, continuous monitoring of the main process parameters. ...
... This is due to the average difference of about 54% in the air temperatures shown in Figure 6a,b. From these findings it is possible to infer that the temperature can be one of the most relevant parameters in the development of an optimized decision process or for any machine learning approach to investigate, as confirmed by [28][29][30][32][33][34][36][37][38][39]43]. The role of CO concentration in the process needs to be clarified, and, probably, integrated with other physical measurements, such as the rheological characteristics and/or the dielectric properties of the dough [52][53][54]. ...
This work copes with the design and implementation of a wireless sensors network architecture to automatically and continuously monitor, for the first time, the manufacturing process of Sardinian Carasau bread. The case of a traditional bakery company facing the challenge of the Food-Industry 4.0 competitiveness is investigated. The process was analyzed to identify the most relevant variables to be monitored during the product manufacturing. Then, a heterogeneous, multi-tier wireless sensors network was designed and realized to allow the real-time control and the data collection during the critical steps of dough production, sheeting, cutting and leavening. Commercial on-the-shelf and cost-effective integrated electronics were employed, making the proposed approach of interest for many practical cases. Finally, a user-friendly interface was provided to enhance the understanding, control and to favor the process monitoring. With the wireless senors network (WSN) we designed, it is possible to monitor environmental parameters (temperature, relative humidity, gas concentrations); cinematic quantities of the belts; and, through a dedicated image processing system, the morphological characteristics of the bread before the baking. The functioning of the WSN was demonstrated and a statistical analysis was performed on the variables monitored during different seasons.
... Approximately only half of the energy applied in the baking processed is harnessed in the oven (Probert and Newborough, 1985) with the remainder wasted; causing a negative impact on the environment and reducing the economic yield of the process (Paton et al., 2013). Consequently, research in baking is frequently interested in the optimal Nomenclature A Linear-anisotropic phase coefficient a Absorption coefficient at spectrum C P Specific heat capacity C 1 ...
... One of the strategies for achieving this temperature uniformity is the use of CFD simulations proposing geometric changes in the oven. Navaneethakrishnan et al. (2010) showed that positioning the heating coil in the side position (Paton et al., 2013) guaranteed the homogeneity of the temperature in a heating oven. Smolka et al. (2010) improved the temperature uniformity in a drying oven via changes in the ventilation system. ...
Convective ovens require a pre-heating stage to achieve a
homogenous temperature. Energy consumption is high during the pre-heating
stage and proportional to pre-heating time. The pre-heating time depends
on the set-point temperature. In this work a pilot scale convective oven
was represented as a nominal scenario, and provided experimental data for
temperature. The strategy consisted of 3-D computational fluid dynamic
(CFD) simulations at different temperatures and geometrical variants of
the internal baffle plate. The simulations were carried out using the
ANSYS CFX package and were contrasted with experimental measurements.
Results proved that the baffle plate geometry exerted an important
hydrodynamic influence in the reduction of the pre-heating time.
... The energy requirement in the baking process is reportedly between 500 and 7300 kJ/kg. [2][3][4][5] It is normally agreed that baking, from an energy consumption point of view, is similar to drying semisolid food. 6 The inverse heat transfer problems (IHTPs) are currently generating a lot of interest in the field of science and engineering. ...
Direct heat transfer problems can be solved analytically or numerically to predict the temperature profile when the thermal properties, boundary conditions, and other relevant parameters are known. Though it is common practice to measure temperature experimentally, heat transfer parameters and boundary conditions are more challenging to measure and can instead be inferred through the use of inverse heat transfer (IHT) techniques, which can be solved through optimization. In this study, the IHT method with the conjugate gradient method is used to determine the energy consumption of bread during the cooking process in a developed baking oven with and without a reflector. A complex variable differentiation method is integrated to calculate the accurate sensitivity coefficient matrix. The results demonstrated that the estimated heat flux is very close to the exact heat flux and relative error is less than measurement errors.
... Baked goods are a widespread dietary component across the globe. Dietary consumption of these substances is crucial for sustaining human nutrition since they serve as a significant reservoir of diverse critical nutrients (Paton et al., 2013;Bredariol et al., 2020;Cappelli et al., 2020). The increasing popularity of bakery products can be attributed to their nutritious attributes and practicality in addressing food security concerns, including feeding programs emergency scenarios, and natural calamities (Arepally et al., 2020). ...
... ▪ The influence of thermal transfer to food flavor is under the spotlight due to the development of food industry and market demand rather than the pharmaceutical industry [12]. For example, the local convective heat transfer coefficient of oven is studied using CFD in terms of bread baking process for better flavor and less energy consumption [13][14][15]; a drying process and its influence to a solvent in terms of can industry is studied using a CFD method [16]; a drying and sterilization process of bottled milk is studied and the influence of the way to place the bottle inside the oven for a heating period is addressed [17]. However, the analysis of thermal process in the pharmaceutical industry is keen to be studied regarding containers, such as vials and needle cylinders. ...
Nonlinear dynamics plays a crucial role particularly in equipment validation of preparation production, validation results of which will significantly influence the results and period of drug registration in drug production processes. In this research, the flow field and temperature field simulation, calculation and analysis are creatively carried out in terms of depyrogenation tunnel, a very popular preparation drying-sterilization equipment in pharmaceutical processes with strong dynamic characteristics. After construction of 3D model of this equipment using Catia and mesh generation applying ANSYS, the computational fluid dynamic (CFD) method and verification of irrelevance method are carried out regarding 6.05 million of meshes to identify the flow velocity model and heat transfer model inside the equipment, to further provide methodology for pharmaceutical process validation and to further optimize the design of control methods. After calculation and simulation, the low-velocity vortices of different sizes inside the hood and the drying chamber are identified, which could cause vials to fall down; meanwhile, vials that are farther away from the outlet receives less heat exchange effect, which would shrink the effective sterilization area, indicating an inadequate validation methodology in pharmaceutical processes.
... This energy saving on a large scale is significant, as explained in Paton et al. (2012b) the annual cost saving is estimated to be at least £0.5 million and carbon savings of more than 5,000 tonnes CO 2 equivalent for UK industry. ...
У статті розглядаються проблеми впливу раціональних режимів роботи хлібопекарських печей, що є важливою задачею роботи печі для значної економії палива. У хлібопекарських печах однією з основних величин, найбільш чуттєвою до зміни навантаження, є температ
... Energy efficiency has not always been the main focus of oven design, with other factors like the simplicity and dependability of operation, accessibility for cleaning, maintenance expenses, consistency of production, and capacity for large production rates being more crucial. Due to this, standard commercial bread ovens typically have an efficiency of less than 50% (Paton et al., 2013). Key quality characteristics are affected by baking operating parameters (texture, moisture content, and surface color). ...
Air impingement method has been widely used in a variety of industrial applications, such as textile and paper drying, turbine cooling, and glass quenching, because it is an efficient technology with high heat and mass transfer rates. This technology has received increasing interest in the field of food processing over the last two decades, such as drying, baking, blanching, freezing, and thawing. In a food processing equipment using air impingement, jets of high‐velocity air (with speeds of 10–50 m/s) are directed at a food product. The performance of the system is influenced by several critical elements, including jet velocity, nozzle array diameter and layout, jet distance, and boundary layer characteristics. The use of computational fluid dynamics, an emerging tool, has been shown to be valuable in the analysis of fluid flow and heat and mass transfer in jet impingement systems. The physical properties of impinging jets, such as turbulent mixing in the free jet zone, stagnation, boundary layer formation, recirculation, and their interactions with food products in terms of heat and mass transfer, have been discussed in this article. The benefits and disadvantages of air jet impingement technology in different food processing applications together with potential trends for improving impingement technology performance were identified and discussed. This review not only contributes to a better understanding of the research status of impingement technology on food processing but also triggers new research opportunities in this field in order to provide more healthy and nutritious food in a more sustainable way to the world's growing population.
... In general, the energy efficiency observed in bigger samples is higher than the efficiency observed in traditional convective ovens: efficiency from 7.7 to 18.3% was measured in meat cooking [33] and from 6 to 13% in bakery products [34,35]. ...
Food heating assisted by radio frequencies has been industrially applied to post-harvest treatment of grains, legumes and various kind of nuts, to tempering and thawing of meat and fish products and to post-baking of biscuits. The design of food processes based on the application of radiofrequencies was often based on rules of thumb, so much so that their intensification could lead significant improvements. One of the subjects under consideration is the shape of the food items that may influence their heating assisted by radiofrequency. In this work, a joint experimental and numerical study on the effects of the spatial configuration of a food sample (chicken meat shaped as a parallelepiped) on the heating pattern in a custom RF oven (40.68 MHz, 50 Ohm, 10 cm electrodes gap, 300 W) is presented. Minced chicken breast samples were shaped as cubes (4 × 4 × 4 cm3) to be organized in different loads and spatial configurations (horizontal or vertical arrays of 2 to 16 cubes). The samples were heated at two radiofrequency operative power levels (225 W and 300 W). Heating rate, temperature uniformity and heating efficiency were determined during each run. A digital twin of the experimental system and process was developed by building and numerically solving a 3D transient mathematical model, taking into account electromagnetic field distribution in air and samples and heat transfer in the food samples. Once validated, the digital tool was used to analyze the heating behavior of the samples, focusing on the most efficient configurations. Both experiments and simulations showed that, given a fixed gap between the electrodes (10 cm), the vertically oriented samples exhibited a larger heating efficiency with respect to the horizontally oriented ones, pointing out that the gap between the top electrode and the samples plays a major role in the heating efficiency. The efficiency was larger (double or even more; >40% vs. 10–15%) in thicker samples (built with two layers of cubes), closer to the top electrode, independently from nominal power. Nevertheless, temperature uniformity in vertical configurations was poorer (6–7 °C) than in horizontal ones (3 °C).
... If the optimum temperature during each process in baking fails, product quality is adversely degraded. The high temperature at the beginning of baking can result in early crust formation, which leads to bread with a shrunken crumb, darkest crust, and higher content of HMF and acrylamide (Chhanwal et al., 2010;Paton, Khatir, Thompson, Kapur, & Toropov, 2013). The presence of water content influences the formation of acrylamide. ...
Conventional hot air baking is a widely used food processing technology, which involves simultaneous heat and mass transfer processes. Chances of acrylamide and hydroxymethylfurfural formation is high in baked products due to high-temperature treatment. Since acrylamide and hydroxymethylfurfural are harmful to human health, it becomes crucial to develop novel baking technologies to mitigate these harmful components without affecting the sensorial properties of the final baked product. The formation of hydroxymethylfurfural and acrylamide are closely related to baking temperature, baking time, and ingredients. Novel technologies and pretreatments are shown promising results to mitigate these harmful components in the end products. This review describes the suitable pretreatment methods, novel baking technologies, and effective post-baking techniques that help mitigate the development of harmful compounds without affecting the textural attributes of baked products. Novel baking technologies, such as vacuum baking, high voltage electrical discharge, supercritical carbon dioxide extrusion process, power ultrasound, infrared, microwave and halogen lamp baking; different pretreatment technologies – ozone treatment, plasma treatment, high-pressure processing, ohmic heating, ultraviolet irradiation and ligh emitting diode treatment are discussed together with a comprehensive insight to the understanding of mechanisms involved in the formation of harmful components during processing and post-baking.
... A number of studies dealt with the improvement of energy efficiency of baking ovens and found that up to 10% savings could be achieved by better optimization of the ovens and an additional 5% by re-designing the ovens with optimum heat transfer coefficients [22,23], which translates into a 2% reduction in specific energy. Another way to achieve energy saving and GHG emission reductions are the use of renewable technologies (solar, wind and biogases) or combined heat and power (CHP) systems that could generate approximately 64,900 MW/h of electricity and reduce GHG emissions by 15,415 tCO 2 . ...
As the new climate change driven regulations are brought into the force and energy prices and sustainability awareness increased, many companies are looking for the most efficient way to reduce their energy consumption and greenhouse gas (GHG) emissions. In this context, the food industry as one of the main energy consumers within the industry sector plays a significant role. This paper analyses the current energy consumption in a biscuit manufacturing company and considers a number of possible solutions for the energy efficiency improvements. The company uses modern and automated production processes and has signed a Climate Change Agreement. The experimental part involves identification of the energy users, as well as analysis of the energy bills, operation times, production schedule and on-site measurements of energy consumption. The opportunities for energy efficiency improvements, GHG emissions and costs reduction are investigated and additional information about the investments and payback period of the proposed improvements discussed. A number of opportunities for improvement are identified within the production area with a potential savings of 23%, which corresponds to EUR 40,534.00 and 190 tCO2, annually. It was found that the significant savings could be achieved by better managing the production lines and reducing operational hours from equipment, with no impact on productivity and no capital investment required. Further savings can be achieved through technical improvements requiring capital investments. All those improvements and savings make a significant contribution in accomplishing environmental targets set out by the FDF1 agreement.
... Third, for the advancement of knowledge, prior studies have yet to assess the energy management of family firms, not least in the food sector. This is especially surprising owing to the substantial volume of extant research interrogating energy management practices in the food industry (Muller et al., 2007;Paton et al., 2013;Corsini et al., 2016). Along these parameters, there are also indications that Turkey has a high density of small firms (Karada g, 2016), many of which are in the food trade (Ozturk and Akoglu, 2020). ...
Purpose
While pursuing energy management, firms simultaneously strive to boost sales as a path towards economic performance. Also, the literature suggests that family firms exhibit greater environmental commitment than their non-family counterparts. To examine these contentions, this review espouses contingency theory to interrogate the correlations of (1) energy consumption targets, (2) energy efficiency enhancing measures, (3) energy consumption monitoring and (4) the domestic sales performance of small family firms in Turkey's food sector.
Design/methodology/approach
Data were sourced from the World Bank Enterprise Survey. A sample of 137 family firms in food production, processing and retail was analysed using non-linear structural equation modelling. Path coefficients were determined to estimate the extent to which energy management practices predict domestic sales.
Findings
The path analysis revealed that although energy consumption targets do not directly increase sales performance, they stimulate firms' energy efficiency enhancement measures and energy consumption monitoring to produce this effect by 21%.
Research limitations/implications
The contingency lens espoused leaves room to capture further antecedents in small family food firms' technical, managerial, ownership, operational and architectural configuration that may also interact with or predict the propensity for energy management.
Practical implications
For practitioners, the inherent findings demonstrate that there are firm-specific material benefits arising from adopting energy management practices. And, although small firms such as family food businesses may have low energy intensities, they can improve their sales performance by setting energy targets, installing energy efficiency enhancing measures and embarking on energy consumption monitoring.
Social implications
Public stakeholders in Turkey such as the Ministry of Energy and Natural Resources, the General Directorate of Energy Affairs and affiliate institutions can reflect on these findings to develop a coherent national energy management policy for small firms. Such initiatives are especially relevant to Turkey and its ambitions to join the EU which requires member states to set up a national energy efficiency action plan.
Originality/value
This inquiry is one of the first to examine energy management in the food sector at the family firm level through the contingency lens. Theoretically, the results draw attention and shed new light on disparate energy management practices and their discrete yet substantial contribution to sales performance.
... Overall, by combining the two approaches, the analyses suggested that bake time can be reduced by up to 10% and the specific energy required baking each loaf by approximately 2%. For UK industry, these savings equate to more than £0.5 million cost and carbon reduction of more than 5000 tonnes CO 2 per year [45]. ...
... Indeed, the air/air exchanger of the baking chamber receives the flow of heat from the heating chamber before conveying it by convection and by radiation to the baking chamber. After about 2000 s, the temperature attains saturation at about 220 C. Our result is comparable to the one obtained in References (Chhanwal et al., 2019;Ploteau et al., 2015;Mistry et al., 2006Mistry et al., , 2011Paton et al., 2013). These results reflect the reality of what happens in bakeries using these ranges of ovens. ...
In this work, we propose a mathematical model describing thermal behavior and heating process optimization of solid fuel bread ovens. Numerical simulation leads to temperature profiles of the oven. The design and implementation of an operating prototype permits us to obtain, with type K thermocouples, experimental temperature profiles in some points of the oven. There is a good agreement between the experimental results and those obtained from the numerical simulation of the proposed model. A permanent temperature value of 220 °C is reached in the baking chamber. It is obtained that the energy efficiency of the oven is 49%. Making use of the objective gain function, it is found that the optimal parameters of the oven are the following: 50 W as optimum operating value of the electric power of the blower, 3 m² as the optimum operating value of the total surface of the baking chamber; and 0.67 as the optimum operating value of the filling factor between the heating chamber and the baking chamber. The developed model serves to better understand the operation, the optimization and to rationally manage energy expenditure related to solid fuel bread ovens in developing countries.
... Most existing works [13,14,15,16] on food manufacturing systems, especially in bakery production line, are based on non-modular model. For example, [13] modelled the optimization of bakery production using methods of scheduling theory. ...
Numerous efforts are being made yearly by researchers to improve the production flow, planning and scheduling of food manufacturing systems through the use of modelling to meet both current and future market demands. In this paper, a Hierarchical Timed Coloured Petri Nets (HTCPN) model was developed for bakery production system using Ladoke Akintola University of Technology (LAUTECH) Bakery, Ogbomoso, Nigeria, as a case study. The HTCPN model was developed consisting of main module and five sub modules. The sub-modules named mixing, fermenting, rolling, cutting and baking modules modelled the sequential processes of converting flour into bread. The model was simulated using Coloured Petri Nets Tools to determine the average production processing times for processing of 50, 100, 150 and 200 kg of flour into bread. The simulation was also extended to determine the utilization rates required at varying units (manual mixing process, the rolling machine, manual cutting process and baking) for processing of 50 and 100kg bags of flour. The model was validated by comparing the simulated and the actual processing times at 5% significance level using statistical t-Test. The simulation results revealed that the production processing times for processing of 50, 100, 150 and 200 kg of flour starting from the mixing process till baking process were 217, 314, 411 and 508 minutes respectively. The utilization rates required at the mixing process unit, the rolling machine unit, the cutting process unit and baking unit were 0.138; 0.115; 0.046; 0.147 respectively for processing of 50kg bags of flour and 0.191; 0.159; 0.064; 0.203 respectively for processing of 100kg bags of flour. Statistically, there were no significant differences between the simulated and the real processing times. This model could be employed to study worker and machine utilization rates as well as production time required to produce bread from a given quantity of flour in the considered bakery production system or other related ones.
... Manickavasagan, Jayas, and White (2008) detected infestation of beetles in wheat grain and Chelladurai, Jayas, and White (2010) classified fungal infections of stored wheat. Paton et al. integrated thermal measurements inside a systematic modeling approach for energy management (Paton, Khatir, Thompson, Kapur, & Toropov, 2013). ...
The present work aims to validate mid-infrared imaging as a promising method for evaluating oven systems. Therefore, a novel approach by analyzing mid-infrared radiation patterns captured by a thermal camera and subsequent image processing was developed. A thermal camera was adapted to two different oven systems: a standard electric deck oven and a novel gas-fired baking oven with integrated volumetric ceramic burners (VCBs). The baked goods were analyzed and key indicators describing the final product quality were determined. Specific volume, surface browning and mid-infrared image processing demonstrated a comparable performance of both oven systems. Furthermore, the determined surface heat homogeneity of the items to be baked was 0.65 ± 0.05 (–) for the electronic oven and 0.70 ± 0.03 (–) for the VCB oven. The proposed approach proved its fundamental qualification for comparing and evaluating different oven systems.
... They also measured local convective heat transfer coefficient on the baked product and analyzed the effects on the required baking time. In the similar way, Paton et al. [43] used numerical simulations to quantify the required energy demand for the mass-production tunnel oven, 13 conducting a detailed analysis of energy flows of the entire system. By optimization of the flow, they calculated that the baking time could be reduced up to 10 %. ...
Food industry is commonly among the top ten energy most intensive industrial branches. Its annual energy requirements record constant increase. Within the food industry, bakeries are one of the largest energy consumers, due to the energy requirements of the baking ovens, which account for more than a half of the total energy required in the whole production process. The baking oven, a key element of every bakery, directly influences the time and energy efficiency of the production process itself, but also the quality and the cost of the final product. Due to the strict food safety and quality regulations and requirements, improvement of the existing processes is usually related to the significant technical, ecological and economical challenges. In the frame of here presented work, an innovative baking oven concept is proposed and developed. The core of this novel baking oven is an employment of the specific properties of the volumetric ceramic burners (VCB) in order to improve overall baking process performances. The VCB principles of operation, its features and characteristics of NIR thermal emissions are discussed in order to provide the basic understanding of the proposed concept and properties of the developed baking oven prototype. With the help of the innovative Validated Virtual Engineering (VVE), a fully functional prototype of the novel baking oven in industrial scale size is designed. In this way, costly conventional trial-and-error procedures are avoided. The simulation tools enable virtual analysis of various constructional and operational modifications of the baking oven. Amongst others, the influence of the burners shape and their planar distribution, the influence of the quartz glass in front of the burners and the design of the exhaust gas guiding system and its recirculation, were investigated. The validation experiments proved i.a. the operating stability of the designed prototype in a wide power and air-fuel equivalence ratio range, the homogeneity of the thermal radiation and the uniform temperature distribution over the baking plates. This novel, VCB-based, gas-powered, deck oven combines the advantages of near-infrared (NIR) thermal radiation, mainly in the wavelength range of 1.3-1.7 μm, with the unique control dynamics, enabling fast power adjustment to the production process requirement. Furthermore, new findings were extracted out of the numerous experimental investigations, regarding the influence of the novel VCB-based baking oven concept on the product quality and improved energy efficiency, production ecology and economy of the baking process. Using 800 g wheat bread loaves, baking properties of the newly developed oven were compared with the baking properties of the conventional electric deck oven of the same size and geometry. The analysis showed that the VKB oven provides the baked goods of the comparable quality and similar sensory properties i.a. crust thickness, desired crust color, crumb porosity, taste, smell, elasticity, etc. In addition, the VCB-based baking oven reduces preheating and baking time of up to 20 %. The resulting reduced fuel input and the use of gas heating instead of electrical energy provide the significant saving of the primary energy and reduction of CO2 emis-sion. The presented results demonstrate the suitability of the innovative baking oven concept with regard to the product quality, process economy and ecology. At the same time, they confirm the high untapped potential of the application of the porous VCB technology in the food industry.
... Al presentarse una variación en la velocidad del aire, la transferencia de calor en el pan se ve afectada. Cuando el aire presenta valores de velocidad pequeño, este le entrega calor al pan para llevarlo a un estado de equilibrio, pero producto de los choques se crea turbulencia aumentando su velocidad, lo cual la transferencia solo se da en la superficie del pan logrando que se caliente y no exista una uniformidad del flujo de calor hacia su interior [17]. ...
En la industria panificadora de nuestro país, es muy común encontrar procesos de producción que se ven afectados de forma directa e indirecta por el bajo nivel de tecnificación que existe en cuanto al diseño y construcción de los hornos. Hecho que se ve reflejado en los inconvenientes que tienen lugar durante el proceso de horneo. La cocción es un proceso que juega un papel importante en la calidad del producto, el cual es influenciado principalmente por la temperatura durante la cocción por lotes. Por lo tanto, en el presente paper se muestra la evaluación de la distribución de calor al interior del horno y se verifican los problemas que se presentan en la transferencia de calor de los panes mediante la herramienta computacional CFD (Dinámica de Fluidos computacional), para de esta manera proponer tres alternativas de rediseño del horno que redunden en mejoras de la distribución del flujo y los procesos de transferencia de calor y momentum en su interior, a fin de establecer un marco comparativo que permita seleccionar la propuesta más óptima para el proceso de cocción.
... Actuellement, de nombreuses études se consacrent à la réduction des consommations d'énergie. Une grande part de celles-ci s'intéressent à des process industriels ou du matériel professionnel, notamment pour la cuisson du pain, de gâteaux ou de pâtisseries (Papasidero et al., 2016;Paton et al., 2013;Ploteau et al., 2015;Therkelsen et al., 2014), mais il existe aujourd'hui des données sur des appareils domestiques de cuisson de pâtes (Cimini and Moresi, 2017) ou de riz (Kanjanapongkul, 2017). Certains travaux récents montrent aussi la possibilité de réaliser des systèmes utilisant l'énergie solaire (Hassen et al., 2016). ...
La cuisson par contact direct est un mode de préparation des aliments très courant à travers le monde, cependant peu d’études s’intéressent à cette problématique à l’échelle domestique. Ces travaux tentent d’apporter une contribution à l’étude des phénomènes mis en jeu durant cette opération. Ce manuscrit débute par une revue de différents facteurs impliqués lors de la cuisson : les consommations d’énergie, les types d’appareils utilisés, les phénomènes physico-chimiques intervenant dans le produit ou les problématiques de modélisation y sont abordés. Il s’en dégage qu’une donnée essentielle est la connaissance du flux de chaleur transmis au produit. Une méthode d’estimation de ce flux basée sur les techniques inverses est développée. Celle-ci a contribué à concevoir un prototype instrumenté permettant de suivre les cinétiques des températures dans la plaque chauffante et dans un élastomère simulant un produit alimentaire. Les résultats obtenus montrent que la méthode permet d’estimer le flux de chaleur transmis avec une bonne précision. Dans un second temps, une étude expérimentale de la cuisson d’une pâte céréalière d’environ 8mm d’épaisseur est présentée. Après avoir caractérisé les propriétés thermophysiques et hydriques, le prototype est utilisé pour suivre les évolutions de différents paramètres comme les températures, le flux de chaleur, la masse en dynamique, et les teneurs en eau. La répétabilité et la variabilité des résultats suivant la température initiale de la plaque sont menés. Ensuite, un modèle 1D simulant les transferts de matière et d’énergie, est utilisé pour étudier les différents facteurs intervenant lors de la cuisson. Un second modèle 2D est réalisé permettant de tester les consommations d’énergie lors d’une opération de cuisson en cadence suivant différents scénarios de conception du prototype.
... The investment payback period for these strategies is considered to be 2 to 4 years. With the numerical simulation of a tunnel oven, it was found that by changing 10% of the input heat energy to the furnace, the exhaust heat energy at a rate of 1.18% will change [17]. ...
Bread has a significant share of the people's meal in the world. Additionally, the bread industry is one of the world's energy consuming industries. Therefore, energy audits in this industry are essential. The intensity of energy consumption in Iran is significantly higher than the global average. As the current trend continues, the country's production and energy consumption levels are equal in 2025. So the need to optimize energy consumption in the various sectors of the industry is necessary. In this paper, the recovery of energy from hot gases which output from the bread baking chimney in one of the largest bread manufacturers in Iran has been studied. For this purpose, composition, temperature and volumetric flow rate of exhaust flue gas analyzed by gas analyzer, thermometers, and flowmeter. By calculating and analyzing of combustion equation, the amount of furnace efficiency, energy recovery potential has been investigated. The results show that with the heat recovery from the exhaust gases, this factory can save up to 200,000 m 3 of gas each year. Also, considering the capacity of industrial bread production in Iran as a whole, the savings potential is estimated to be approximately 7 million m 3 /year.
... As it can be seen, the energy associated to water evaporation is substantial (49.6% in average), and is greater for large samples. Using a system modeling approach for bread baking, Paton et al. (2013) found that the energy required for moisture evaporation was Complimentary Contributor Copy slightly higher than the sensible heat; similarly during contact baking of pancake batter, Feyissa et al. (2011) found that the energy required for evaporation was much higher than the sensible heat. Considering the sample energy consumption values calculated using the Eq. ...
Oven cooking of food is a traditional and widely used technology, both at a household and industrial level, which confers to foods unique organoleptic properties, which can not be accomplished using other available technologies. At the same time, it is a highly energetic intensive process, due to the fact that most foods have a high level of water content, which is partially evaporated during roasting. Any attempts to minimize energy consumption of the process must be done carefully, since the quality of the product should not be negatively affected and, on several occasions, there are security and legislative standards to comply. In this chapter the energy consumption during roasting of beef semitendinosus muscle samples has been estimated, using an electric oven. The samples were cooked at oven temperature between 172 and 223 °C until they reach a core temperature of 72 °C. A simple procedure to determine the effective power of the oven from experimental measurements is proposed, which can be applied to other situations and processes. Then, from the experimental results, energy consumption of the oven between 4 to 6.3 MJ/kg of raw sample was found, while energy consumption of sample varies between 484 to 780 kJ/kg of raw sample. So, the ratio of sample energy consumption to oven energy consumption, provide a simple estimation of the energy efficiency of the process, which was found to be between 7.7 to 18.3%. Furthermore, a mathematical model of the beef roasting process has been used to estimate the actual energy consumption of the samples, which fit well with the experimental results.
... Therefore, it is critical to follow the temperature evolution of this region, which defined the strategic placement of thermocouples T1 and T2. Many authors state that when bakery product inner temperature reaches 95-98°C complete starch gelatinization and protein denaturation are achieved, thus the liquid emulsion is completely transformed in a solid porous structure (Ahrné et al. 2007;Purlis 2011;Paton et al. 2013). Furthermore, our research group confirms this fact in a previous work studying the baking process of muffin, a similar product to sponge cake under study (Ureta et al. 2014). ...
Sponge cake is a sweet bakery product that begins as a fluid batter and, during baking, transforms into a porous solid, presenting an important volume expansion. The aim of this work was, first of all, to study experimentally the influence of operative conditions (natural and forced convection; oven temperature, from 140 to 180 °C; steam addition) on volume expansion and the heat transfer dynamics during baking of sponge cake. It was observed that an increase in oven temperature, airflow and steam injection produces an increase in volume expansion. Secondly, a mathematical model was developed to simulate heat transfer coupled with volume expansion. Both experimental and simulated temperature profiles verified that the last region to achieve a correct degree of baking is the one near the crust around the axial axis. In consequence, the minimal baking time was defined as the average time at which this region reaches 95–98 °C. The baking time was strongly affected by the effective oven temperature, with a slight influence of the convection mode.
... Basically the oven during the cooking process changes its thermodynamic state. It is not possible to consider steady state conditions, because parameters as work, energy and mass fluxes continuatively change during the test [13]. ...
The management optimization of energy fluxes applied in the professional cooking sector has an attractive potential, and represents a big step ahead, because it is characterized by a high energy demand and has a large diffusion all over the world. Furthermore, professional cooking sector still presents significant possibilities for energy efficiency enhancements, in both design solutions and operating strategies. The present study focuses on energy efficiency analyses on combined ovens for professional use. In the initial phase of the evaluation, energy efficiency standards EFCEM, ENAC and ASTM have been compared with experimental results. Discrepancies were shown by means of a systemic application of the mentioned standards to a specially instrumented prototype of professional oven. Different test conditions do not allow a meaningful comparison of test results, leading to the definition of a new methodology for the energy efficiency evaluation of a combined oven. structured on the experimental analysis of the balance of fluxes incoming and outcoming from the oven in different cooking modalities. It allows improving the knowledge of the machine and, afterwards, helps in the definition of different design choices, derived from the analysis.
... The food and drinks industry is a significant user of resources such as water, energy, and packaging materials and generates substantial quantities of waste and emissions [1][2][3][4][5]. As energy prices and globalisation continue to escalate, food manufacturers seek opportunities to reduce production costs without adversely affecting output, profitability and the quality of the final products. ...
Continuous frying systems are very energy intensive. They also involve the interaction of many variables and complex heat and mass transfer processes. Better control of these processes can lead not only to improved product quality but also energy reduction. This paper presents a model that can simulate the dynamic behaviour of a continuous frying system in sufficient detail that enables the influence of controls on the important product attributes of moisture and oil content to be investigated. A conjugate 2-D transient model of the fryer was used to develop correlations for the oil and moisture content based on the important fryer control variables, namely supply oil temperature, potato mass throughput, fryer paddle velocity and crisp takeout velocity. The correlations were validated against data for an industrial continuous fryer system and used within the overall frying system model which was implemented in MATLAB. Proportional Integral (PI) controls implemented within the MATLAB/Simulink environment have shown that closer control of the important parameters can lead to 10% energy savings compared to the actual industrial frying system. The modelling approaches developed can also be used to investigate further improvements in the design and control of continuous frying systems.
... In this sense, numerous authors have used the bakery product inner thermal histories to define a baking time that assures complete starch gelatinization and protein denaturation, features that are achieved when the product temperature reaches 95-98°C (Therdthai et al. 2002;Ahrné et al. 2007;Purlis 2011;Paton et al. 2013). ...
Baking is a decisive stage in the production of bakery products, in general—muffins, in particular—for most of the quality attributes of the final products depend on it. The aim of this work is to model the kinetics of muffin crust color development during baking and to evaluate the feasibility of this kinetic model to predict the baking times. Surface color is represented by the Browning Index, and the effect of baking temperature (from 140 to 220 °C) and process convective characteristics (natural convection, forced convection, and steam-assisted forced convection) are analyzed. Minimal baking times are calculated from experimental core temperature measurements. The modeling of browning kinetics, which incorporates the optimal crust color determined by sensory analysis, allows the estimation of optimal baking times. For all the tested conditions t
op > t
min, assuring a product whose inner structure was already totally baked. Finally, minimal, half, and optimal baking times present an exponential dependence with the oven temperature. Besides, there are no significant differences between both forced convection modes.
... As it can be seen, the energy associated to water evaporation is substantial (49.6% in average), and is greater for large samples. Using a system modeling approach for bread baking, Paton et al. (2013) found that the energy required for moisture evaporation was Complimentary Contributor Copy slightly higher than the sensible heat; similarly during contact baking of pancake batter, Feyissa et al. (2011) found that the energy required for evaporation was much higher than the sensible heat. Considering the sample energy consumption values calculated using the Eq. ...
Energy consumption of buildings has grown in parallel with the improvement of the lifestyle of the occupants. This growth in consumption of housing affects the environmental and ecological conditions. Today, the main challenge is to increase the awareness of users, by maintaining elevated lifestyle, on the one hand, and educing consumptions so as to minimize the impact on the environment, on the other hand.
In a construction sector constantly looking for new technologies for energy saving and energy efficiency, the role of the end user becomes crucial for the optimal management and responsible use of resources.
The operating conditions of the macro “building-plant-users” system are determined or verified by methods of the energy performance calculation shown in European Standard, EN 15603:2008. These methods have a different degree of detail depending on the purpose: the standard calculation methods, used in energy certification, are useful to evaluate the energy condition of the building stock or to compare the consumptions of several buildings; the design and tailored calculation methods based on design data and real consumption, instead, allow to analyse the characteristics of the building envelope, plant and user behaviour in order to identify the real energy needs and to identify any malfunctions, performing an energy audit of the system that permits to photograph the current status of energy uses.
The standard method is based on a steady state approach in which use and climate are represented according to standard conditions and building as built. The design method is based on standard use and climate but the building is represented as designed. The tailored method uses actual data for use, climate and building. Finally, the standard includes the measured or operational method based on real energy consumption and characteristics of building.
In this work the tailored method is evaluated. This method provides different time range of calculation monthly and hourly) according to the purpose of the study.
... It is clear that uneven mutual positioning of the heaters and modified distribution of the holes in the horizontal wall could improve the spatial temperature field in the storage chamber. This improvement could be relatively easily obtained by employing an optimisation procedure as performed in the works of Khatir [28] and Paton [29] for a bread-baking oven. Table 4 Velocities (in m/s) measured (Column 1) and computed (Column 2) at the points shown in Fig. 9. Column 3 demonstrates the relative discrepancy (in %), which is defined in Eq. (2). ...
This paper discusses a 3-D Computational Fluid Dynamics (CFD) model and presents experimental analysis of the flow and thermal processes within a laboratory heating oven with a natural air circulation. This device is used to store laboratory samples and products at a high, constant and spatially uniform temperature. The mathematical model included heat conduction in the insulated walls and convective and radiative (between walls) heat transfer in the volume of air within the oven. To formulate the mathematical model, a number of experiments were carried out to determine the temperature boundary conditions along the U-shaped heaters and the emissivity of the internal and external walls to determine the radiative heat fluxes. In addition, to validate the spatial temperature and velocity fields in the storage chamber and on the external oven walls, a set of thermocouples and Particle Image Velocimetry (PIV) were employed. The existing device was assessed in four configurations using a certification procedure that was performed at its maximum temperature level. The device was then numerically simulated using the mathematical model developed for this study. The results show satisfactory agreement between the experimental and computational velocity and temperature values. Furthermore, this study developed potential changes for the construction of this device that will improve the temperature uniformity within the storage space.
An improved electric baking oven was designed and fabricated using locally available materials for baking cakes and biscuits. Provisions of necessary adjustments were employed for ensuring uniform distribution of heat in all trays of the baking chamber. Its baking characteristics in terms of baking time, specific volume, and product quality in terms of sensory attributes were evaluated. The oven was found to be quite satisfactory in functioning for baking cakes and biscuits. Total time was only 15–28 min for baking the cake samples in the oven. On the other hand, comparatively, a bit longer time 18–35 min required for baking the biscuit samples. Baking cost was lesser in baking small‐sized cakes and biscuits than those of large sized. The quality of baked products was better in terms of taste, color, flavor, texture, and appearance than ordinary market products. Loaf volume of each cake (with 4 × 5 × 8 cm³) was 100%, which gave specific volume of 652.8 cm³/kg. Similarly, the specific volume of biscuits was 810 cm³/kg. The electric baking oven is quite efficient in baking quality cakes and biscuits uniformly, which can be provided to rural small entrepreneurs for commercial manufacturing of biscuits and cakes.
The impact of heat on food processing is important for improving the sensory and nutritional characteristics of foods while also increasing the shelf life by decreasing enzymatic and biochemical degradation reactions and removing water from the food structure. In addition to the positive features of heat application, it should also be considered that it requires high operating costs. The high-temperature food processing methods reviewed in this chapter include cooking, baking, roasting, frying, and thawing, which are unit operations in which heat is applied to foods to increase the shelf life or to improve the eating quality. In this chapter, first, the theoretical basis of the food processing operations is described. Then, processing parameters and the influence of the unit operations on the physicochemical and nutritional properties of foods are indicated. The methods and equipment used to apply these theoretical principles into practice are described in detail, and new technologies providing energy savings, lower labor costs, and improving product quality are discussed in the following sections.
Baking temperature and time are among the conditions for producing good quality cakes. The aim of this study was to investigate the effects of baking temperature and time on the volume expansion, moisture content, and texture of moist cakes baked in either an air fryer or a convection oven. The cakes were baked under different conditions: (1) baking temperature of 150 °C, 160 °C, and 170 °C for both air fryer and convection oven and (2) baking time of 25, 30, 35 min for air fryer and 35, 40, 45 min for convection oven. Baking temperature and time were found to have a significant (p < 0.05) effect on the relative height, moisture content, firmness and color of the product but no significant effect on the springiness of the product. Based on the numerical optimization method, the optimum condition in an air fryer was 150 °C for 25 min. These optimized conditions resulted in higher relative height (37.19%), higher moisture content (28.80%), lower crumb firmness and chewiness (5.05 N and 1.42 N respectively) as well as higher overall acceptance score (5.70) as compared to optimum condition in convection oven (150 °C at 55 min). Moreover, baking in the presence of rapid air flow in an air fryer may be declared that it is possible to produce high-quality moist cake with minimum baking temperature and shorter baking time.
To address the global challenge of the climate change, more strict legislations worldwide on carbon emission reductions have put energy intensive industries under immense pressure to improve the energy efficiency. Due to the lack of technical support and financial incentives, a range of technical and economic barriers still exist for small-medium enterprises (SMEs). This paper first introduces a point energy technology, which is developed for SMEs to improve the insight of the energy usage in the manufacturing processes and installed in a local bakery. Statistical analysis of electricity consumption data over a seven-day period is conducted, including the identification of operational modes for individual processing units using an enhanced clustering method and the voltage unbalance conditions associated with these identified modes. Two technical strategies, namely electrical load allotment and voltage unbalance minimisation, are then proposed, which could attain more than 800 kwh energy saving during this period and the current unbalance could be reduced to less than 10%. In addition, the genetic algorithm is deployed to solve the job shop scheduling problem based upon the commercial electrical tariffs, and this reduces the electricity bill by £80 per day in the case study. Implementation of the recommendations based on the above analysis therefore may potentially yield significant financial and environmental benefits.
In this paper experimental and CFD numerical analyses of an air-forced convection rotary bread-baking oven are presented. A particular experimental methodology for the thermo-fluid dynamic characterization of the rotary oven has been adopted. The purpose-designed on-board experimental apparatus represents a useful industrial test bench and, at the same time, can be used to collect data for the final user. The experimental apparatus can operate in stand-alone mode and under the actual cavity conditions in terms of temperature and humidity.
A fully 3D numerical CFD model of the rotary bread-baking oven is proposed. By using the numerical model, validated by the experimental results, it is possible to highlight the airflow pattern inside the oven cavity and understand how the loaves change the airflow pattern inside the cooking chamber. Through the data collected using the experimental tests and CFD numerical simulations, some improvements in terms of airflow management inside the cooking chamber can be made. Through these improvements, the final user (as for instance bakers, either industrial or artisanal) can exploit several advantages in terms of energy saving and reduction of non-conformal baked products in relation with the localization of the recirculation zones and zones with higher velocity inside the oven cavity.
Baking involves many coupled phenomena occurring inside and outside the food product. This chapter examines how the food product can be described in terms of phases and components and how the heat, mass and momentum transfer can be modelled in a more or less simplified manner. The simplification assumptions mainly depend on the question to be answered. Two modelling examples are given. The conclusion focuses on trends and future challenges in the modelling of baking processes.
An oven has been commonly employed to cure powder painted on metal parts for an air-conditioning production. There are many options to improve efficiency in fuel use for the paint curing oven; however some options need deep understanding to prove the possibility of thermal performance. In this work, computational fluid dynamic (CFD) modeling and simulation have been applied to study the temperature distribution and the flow pattern in the paint curing oven on a large scale. The CFD model has been validated against real data. The validated CFD model is used to investigate the temperature distribution and the flow pattern for two proposed options: eliminating stored heat and rearranging airflow. Results demonstrate that both cases provide temperature increase of 1.9 and 1.3. °C for air compared to the present paint curing oven. It can be concluded that the two proposed options are applicable for further implementation to the present paint curing oven.
Steam sterilisation using autoclaves or retorts is a widely used thermal process in the food processing and pharmaceutical industries. Unfortunately, sterilisation, using steam, consumes a significant amount of energy and is known to cause unwanted peak energy demand when a number of autoclaves operate in parallel. The objective of this paper is to extend the previously published numerical methodology developed to simulate in detail the thermal energy consumption of an industrial sized empty autoclave used for steam sterilisation, to include products, in this case, intravenous solution packed in plastic pouches and a steam flow controller. The external parameters supplied to the numerically modelled controller are the maximum steam flow rate and the autoclave temperature as a function of time which it needs to maintain. The numerical model is then used to predict the actual transient temperature and pressure profiles and the details of the mass transfers in the autoclave during a sterilisation cycle, the transient temperature distribution within the products as well as details of the transient thermal energy consumption. The results from numerical modelling were validated with measurements obtained under actual operating conditions. The simulated total steam consumption was within 3% of the measured data. A reduction of 8% in steam consumption was obtained due to insulation on the outer walls.
The objective of this study is to improve energy efficiency of an oven used for the conventional baking of French bread. Experiments performed to validate a numerical model and test different infrared emitters are presented. In order to provide a relevant experimental database, we first instrumented an industrial electrical static oven. The modifications made to the oven and instrumentation installed allows monitoring baking kinetics. The quantities measured are bread mass, temperature field, volume expansion and pressure. An energy balance is calculated to define the energy necessary to cook one “baguette”. Heat is provided by natural convection, direct conduction and mainly by infrared radiation to the dough. To improve energy efficiency, short infrared emitters are arranged on the vault instead of traditional electrical resistances made of reinforced metal alloy. These emitters allow increasing radiation heat transfer. Then, baking under short infrared emitters is carried out at lower air temperature, for the same total baking time. Energy consumption is analyzed and compared in both cases.
A numerical model has been developed to simulate heat and mass transfer phenomena during a steam air sterilisation cycle of an operating industrial autoclave. The objective of this paper is to present a practical methodology applicable for evaluating transient heat and mass transfer phenomena by assuming quasisteady state conditions. As a first step, an empty autoclave was considered. The developed model utilises measured steam flow rates as input parameters and predicts the transient temperature and pressure profiles. The numerical results are validated against two measured on-site data sets, one obtained in summer and the other in winter. The detailed numerical results allow the major heat losses within the process were identified to be determined, thus presenting the importance of having such a numerical model when conducting analyses for evaluating potential thermal energy savings in thermal processes. It is shown, that in any cyclic operation involving the heating and cooling of the containing walls, the insulation should be placed on the heated side.
The paper deals with the temperature uniformity and pressure loss in the hearth of the baking finish oven of the Enameled Wire with catalytic combustion and circulating flow. A numerical model of a RXHW3600 24-wire baking finish oven is built by Fluent, which is validated by the experimental velocities of the cold flow. The maximum temperature difference along the width direction of the hearth (MAX ΔT) and the pressure drop along the computational domain (MAX ΔP) are mainly investigated numerically. It shows that the MAX ΔT is too high, which will lead to a poor wire quality and large energy consumption. The MAX ΔP is very high too, which will increase the power loss. Detailed numerical work is carried out to investigate the correlations between the configuration parameters (branch air duct spacing, hearth width and air flow rate) and the MAX ΔT/MAX ΔP. Orthogonal method is used to determine the optimal structure parameters of the air distribution device. It is shown that the optimal air distribution device significantly reduces the MAX ΔT and the MAX ΔP. The MAX ΔT decreases by 79.1% and the MAX ΔP decreases by 37.8% respectively after optimization for the single-baffle structure. The MAX ΔT decreases by 78.1% and the MAX ΔP decreases by 42.9% after optimization for the three-baffle structure.
This paper presents the shape optimisation of a natural air circulation heating oven based on an experimentally validated 3-D CFD model. The oven is designed to store laboratory samples and products at high, constant and spatially uniform temperature conditions. Thus, the aim of the proposed optimisation procedure, which uses the genetic algorithm (GA), is to improve the spatial uniformity of temperature within the storage space. The objective function (OF), which is defined as the maximum difference between the temperatures in the geometric centre and one of the corners of the chamber, is minimised. The OF is computed using a mathematical model that is validated with a set of thermocouples and Particle Image Velocimetry (PIV), which capture the spatial temperature and velocity fields, respectively. The model is applied to the 3-D geometry of the real oven. Based on the results of the model, two optimisation procedures are performed to optimally position the electric heater and air distribution gaps using simplified geometries of the device. The optimised solutions are then applied to the real 3-D model and show a substantial improvement in the uniformity of the temperature field in the storage chamber.
Industrial ovens consume a sizable proportion of energy within the manufacturing sector. Although there has been considerable research into energy reduction of industrial processes throughout literature, there is not yet a generalised tool to reduce energy within industrial ovens. The systematic approach presented aims to guide an engineer through five stages of oven optimisation. These involve defining the scope of the optimisation project, measuring and analysing process variables in order to develop fundamental understanding of the system so that an optimisation plan can be established and then implemented. The paper gives an application example of the methodology to a curing oven within a masking tape manufacturing facility. This approach showed an estimated annual saving of 1,658,000 kWh (29% reduction of the oven's energy consumption and a 4.7% reduction of the whole plant's energy consumption) with very little capital expenditure. As the methodology can be tailored to accommodate individual optimisation options for each oven scenario, while still providing a clear pathway, it has potential applications within the wider manufacturing industry.
A mathematical model representing temperature and moisture content in bread during baking is developed. The model employs the coupled partial differential equations proposed by Luikov. Dependences of mass and thermal properties of dough on temperature and moisture content are included in the model. Resulting system of non-linear partial differential equations in time and one space dimension is reduced to algebraic system by applying a finite difference numerical method. A numerical solution of the model equations is obtained and simultaneous heat and moisture transfer in dough during baking is predicted. The changes of temperature and moisture content during the time of the process are graphically presented and commented.
The combined surface heat transfer coefficient is a determining parameter of convective baking process time and efficiency, as well as the resulting food product quality. By this study, the combined surface heat transfer coefficient term was determined at the convective oven temperature range of 70–220°C, with fan (turbo) and without fan (static oven) applications. The methods of “Lumped Capacity” and “Time–Temperature Matching” were used. Both methods utilize the time–temperature data at a fixed position of a definite material, during unsteady state heating up period inside the convective oven. The increase in oven temperature and the fan application in the oven derived higher calculated values of surface heat transfer coefficients. Good agreement was observed between both methods and the literature values. The given methods are applicable to other oven types and heating modes.
Experimental and computational fluid dynamics (CFD) analyses of the thermal air flow distribution in a 3-zone small scale forced convection bread-baking oven are undertaken. Following industrial bread-making practise, the oven is controlled at different (constant) temperatures within each zone and a CFD model is developed and validated against experimental data collected within the oven. The CFD results demonstrate that careful selection of the flow model, together with implementation of realistic boundary conditions, give accurate temperature predictions throughout the oven. The CFD model is used to predict the flow and thermal fields within the oven and to show how key features, such as regions of recirculating flow, depend on the speeds of the impinging jets.
This article presents some results on the energy demand in conventional bread baking and in the processing of frozen part baked breads, resulting from the “EU-FRESHBAKE” European project (FP6). Bread baking is one of the most energy demanding processes (around 4MJ/kg), compared with other thermal processes such as canning. However, there is a large variability of data in the literature. For partial baking, bread has to be baked twice. It may also be frozen after part baking, which will increase the total energy demand. Results obtained with equipment used by craft bakeries are presented. Conventional and frozen part baked processes are compared. The effect of occupation ratio on the overall energy demand is also assessed. It was observed that 15–20% of the total energy is used for heating up the dough and 10–20% for crust drying. Pre-heating of the oven represents another significant energy demand. The energy demand for freezing is comparable to that for baking. An Energy Efficiency Index is used to assess the ratio of energy effectively transferred to the dough during baking. Part baked frozen technology demands about 2.2 times as much energy as conventional bread making process.
In an industrial continuous bread-baking oven, dough/bread is travelling inside the oven chamber on its top and bottom tracks connected by a U-turn. The temperature profile of dough/bread during this whole travelling period, which depends on the distribution of temperature and air flow in the oven chamber, dominates the final product quality. In this study, a two-dimensional (2D) CFD model for the whole baking oven chamber has been developed to facilitate a better understanding of the baking process. The transient simulation of the continuous movement of dough/bread in the oven was achieved using the sliding mesh technique. The U-turn movement of bread was successfully simulated by dividing the solution domain into two parts, then flipping and aligning them along the travelling tracks. The 2D CFD modelling was proven to be a useful approach to study the unsteady heat transfer in the oven as well as the heating history and temperature distribution within dough/bread.
A naive model of starch gelatinization kinetics was constructed to determine a control parameter of the baking process (i.e. a baking index).Bread dough samples were instantaneously heated at different temperatures (60–90 °C) for varying times and then subjected to differential scanning calorimetry to evaluate the extent of starch gelatinization. Calorimetric traces, after smoothing and standardization, were deconvoluted into one or two Gaussian curves, depending on the treatment temperature and time. This suggests that the system is a mixture of two components, the second of which was found to have lower gelatinization rate.The kinetic parameterization was only applied to the second Gaussian curve. It was shown that the trend of the second peak fits well with firstorder kinetics, where the rate constant varies with temperature according to the Arrhenius equation (K0 = 2.8 × 1018/s; Ea = 139 kJmol).
This book looks at the problems of energy engineering from a systems point of view. It encompasses the disciplines of electrical, mechanical, industrial, and process engineering as well as project/system management.
We use first-law and second-law efficiencies on 2 multi-process food processing plants. These efficiencies are 59.6 and 19.4% for a condensed milk plant and 43.0 and 15.5% for the bakery plant. Improvements in both first-law and second-law efficiencies for the bakery can be achieved by reducing the mass of dough moulds and recovery of energy in the bake-oven exhaust to heat the air in the proofing oven. Replacement of the flash-cooling process in the condensed-milk plant by a combination of boiling at 100 °C and cooling via a vapour-compression refrigerator would lead to significant improvements in plant efficiencies.
The industrial baking of cereal products is commonly performed in tunnel ovens, which give operators high flexibility for adjusting baking conditions to optimum values. This paper discusses the application of a CFD approach to predict the air temperature and velocity profiles inside the baking chamber of an industrial indirect gas-fired tunnel oven used for biscuit baking. We used two three-dimensional CFD models (one not covering the conveying band of biscuits and the other including it) to describe the complex air circulation resulting from the mechanisms of air input and exit at the ends of the oven and of air extraction through the different extraction points located along the oven length. Comparison of numerical results with experimental measurements shows a fairly close agreement in the qualitative prediction and a few inaccuracies in the quantitative prediction of the air temperature profiles within the baking chamber. Furthermore, the comparison also reveals great differences in the air velocity profiles.
Using water as the working fluid, air-to-air heat exchangers using thermosyphon heat pipes were designed, constructed and tested under medium temperature (below 300°C) operating conditions. A heat exchanger test rig has been constructed and developed wherein the heated air is recycled to the counterflow heat exchanger. The lengths of both the evaporator section and the condenser section of the heat exchangers were 300 mm and the central adiabatic section was 150 mm. The heat exchangers which were tested used (1) continuous plate finned copper tubes, (2) circular, spirally-finned steel tubes and (3) bare copper tubes for their respective heat pipes. The working fluid was water with a fill ratio of 60% of the evaporator section length. The air face velocity range was from 1.5 to 5 m/s and the heat input into the evaporator section inlet was varied between 4 and 20 kW using electric heating elements. The heat exchangers showed high effectiveness compared with similar heat exchangers using other working fluids, such as Freon 22 (R22). The rectangular plate finned copper thermosyphon heat exchanger had the best performance but there was a limitation on testing this configuration that the adiabatic section temperature operating condition did not exceed 200°C, in order not to exceed the safe working pressure. A steel pipe heat exchanger will be used in the industrial application to which the project is directed.This heat exchanger has been designed, manufactured and tested for heat recovery in industry with medium temperatures (lower than 300°C), for example in bakeries to recover flue gas energy from the oven to heat up the proofing oven or other low temperature heating functions.
A bakery pilot oven is modeled using computational fluid dynamics software. This approach relies on integration of an instrument into modeled geometry. The instrument is a heat flux measuring device that can be used in the industrial baking process. All three heat transfer mechanisms are considered and coupled with turbulent flow. Turbulence is taken into account via the k–ε realizable model whereas the surface-to-surface model simulates the radiation. Additionally, buoyancy forces are introduced by means of a weakly compressible formulation. The model predictions show a good qualitative agreement with the experimental measurements. A quantitative agreement was obtained to some extent. Limitations came from the difficulty to measure the temperature of the radiant surfaces of the oven. Operating conditions used are typical of bakery products and, as expected, radiation was the dominant mode of heat transfer. The integration of the instrument was useful for assessing the model. Since it is designed for industrial use, it may be a valuable tool for future challenges in the field, such as simulation of an industrial scale oven.
The main objective of the study was to compare the effects of halogen lamp–microwave combination baking on quality of breads with other baking methods (conventional, microwave and halogen lamp baking). It was also aimed to improve the quality of microwave baked breads by using combination oven. Weight loss, specific volume, firmness and color of the breads were measured as quality parameters. Halogen lamp–microwave combination oven reduced the conventional baking time of breads by about 75%. Microwave heating was found to be the dominant mechanism in halogen lamp–microwave combination baking in terms of affecting weight loss and texture development. Increasing in halogen lamp power reduced specific volume and increased weight loss, firmness and ΔE values of breads in combination baking. Breads baked in halogen lamp–microwave combination oven had specific volume and color values comparable with the conventionally baked breads but their weight loss and firmness values were still higher.
An experimental investigation of the convective heat transfer on a flat surface in a multiple-jet system is described. A thin
metal sheet was heated electrically and cooled from one side. On the other black coated side the temperature field was measured
using an IR camera. Varied parameters were the jet Reynolds number in the range from 1,400 to 41,400, the normalized distance
nozzle to sheet H/d from 1 to 10, and the normalized nozzle spacing S/d from 2 to 10. A geometrical arrangement of nine nozzle in-line arrays was tested. The results show that the multiple-jet
system enhances the local and average heat transfer in comparison with that of a single nozzle. A maximum of the heat transfer
was found for the normalized spacing S/d=6.0. The normalized distance H/d has nearly no effect on the heat transfer in the range 2≤H/d≤4. The maximum average Nusselt number was correlated as a function of the jet Reynolds number
(\textNu\textavmax = 0.104\textRe0.7 ). ({\text{Nu}}_{{{\text{av}}_{\max } }} = 0.104\,\text{Re}^{0.7} ).
Vacuum cooling is a rapid evaporative cooling technique, which can be applied to specific foods and in particular vegetables. Increased competitiveness together with greater concerns about product safety and quality has encouraged some food manufacturers to use vacuum cooling technology. The advantages of vacuum cooling include shorter processing times, consequent energy savings, improved product shelf life, quality and safety. However, the cooling technique has a limited range of application. Traditionally, products such as lettuce and mushrooms have been cooled under vacuum. Recent research has highlighted the possible applications of vacuum cooling for cooling meat and bakery products, fruits and vegetables. This paper comprehensively reviews the current state of the technology. It is concluded that while vacuum cooling remains a highly specialised cooling technique, with continuing research its application may make its use in the food and vegetable processing industries more competitive and widespread.
Food processing systems using air impingement consist of jets of high-velocity air (10–100 m/s) exiting from nozzles and impinging on a food product. The factors affecting efficiency of impingement systems include the nozzle exit velocity, nozzle design, boundary layer characteristics on the surface of the product and the design of the impingement equipment. In the present research, visualization studies were conducted to determine the importance and implication of these factors. Flow under the jets was visualized using planar flow visualization techniques for various nozzle diameters (D), lengths (L) and nozzle to plate spacings (H) for flow over flat surfaces and food products with single and double jets. Studies were conducted on the transition features, recirculation, confinement and boundary layer flow characteristics. Ideal range for the characteristic nondimensional ratio (H/D) was determined to be 6–8. The actual ratio will depend on the transition effect and the induction of turbulence in the jet wake, which depends on the Reynolds number (Re) based on nozzle exit conditions and the L/D ratio of the nozzle. Surface roughness affected the roughness Reynolds number (Rep) which in turn influenced the boundary layer characteristics.
Computational fluid dynamics (CFD) is a powerful numerical tool that is becoming widely used to simulate many processes in the food industry. Recent progression in computing efficacy coupled with reduced costs of CFD software packages has advanced CFD as a viable technique to provide effective and efficient design solutions. This paper discusses the fundamentals involved in developing a CFD solution. It also provides a state-of-the-art review on various CFD applications in the food industry such as ventilation, drying, sterilisation, refrigeration, cold display and storage, and mixing and elucidates the physical models most commonly used in these applications. The challenges faced by modellers using CFD in the food industry are also discussed.
A general, numerical, marching procedure is presented for the calculation of the transport processes in three-dimensional flows characterised by the presence of one coordinate in which physical influences are exerted in only one direction. Such flows give rise to parabolic differential equations and so can be called three-dimensional parabolic flows. The procedure can be regarded as a boundary-layer method, provided it is recognised that, unlike earlier published methods with this name, it takes full account of the cross-stream diffusion of momentum, etc., and of the pressure variation in the cross-stream plane. The pressure field is determined by: first calculating an intermediate velocity field based on an estimated pressure field; and then obtaining appropriate correction so as to satisfy the continuity equation. To illustrate the procedure, calculations are presented for the developing laminar flow and heat transfer in a square duct with a laterally-moving wall.
This book explains energy auditing in buildings and industry, providing all the information one needs to establish an energy audit program for one's facility. Accounting procedures, electrical, mechanical, building and process systems analysis, life cycle costing, and maintenance management are all covered. Case studies for schools, hospitals, government buildings and food service facilities are presented along with sample audit forms and checklists.
This article describes an implementation of a particular design of experiment (DoE) plan based upon optimal Latin hypercubes that have certain space-filling and uniformity properties with the goal of maximizing the information gained. The feature emphasized here is the concept of simultaneous model building and model validation plans whose union contains the same properties as the component sets. Two Latin hypercube DoE are constructed simultaneously for use in a meta-modelling context for model building and model validation. The goal is to optimize the uniformity of both sets with respect to space-filling properties of the designs whilst satisfying the key concept that the merged DoE, comprising the union of build and validation sets, has similar space-filling properties. This represents a development of an optimal sampling approach for the first iteration-the initial model building and validation where most information is gained to take the fun advantage of parallel computing. A permutation genetic algorithm using several genetic operator strategies is implemented in which fitness evaluation is based upon the Audze-Eglais potential energy function, and an example is presented based upon the well-known six-hump camel back function. The relative efficiency of the strategies and the associated computational aspects are discussed with respect to the quality of the designs obtained. The requirement for such design approaches arises from the need for multiple calls to traditionally expensive system and discipline analyses within iterative mulfi-disciplinary optimisation frameworks.
Energy Efficiency Yields High Return on Investment
- P Frank
P. Frank, Energy Efficiency Yields High Return on Investment, in Baking Management, Penton Media, Inc, 2009, accessed 23.02.12], http://baking-management.com/production_solutions/energy-efficiencyyields-high-0609.
Energy consumption in the baking industry
- A Christensen
- R P Singh
A. Christensen, R.P. Singh, Energy consumption in the baking industry, Third
International Congress on Engineering and Food, Dublin (1984).