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1
Tai, Yanni, Haibin Qu, and Xingchu Gong. "Design Space Calculation and Continuous Improvement Considering a Noise Parameter: A Case Study of Ethanol Precipitation Process Optimization for Carthami Flos Extract." Separations 8, no. 6 (2021): 74. http://dx.doi.org/10.3390/separations8060074.
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The optimization of process parameters in the pharmaceutical industry is often carried out according to the Quality by Design (QbD) concept. QbD also emphasizes that continuous improvement should be performed in life cycle management. Process parameters that are difficult to control in actual production can be regarded as noise parameters. In this study, based on the QbD concept, the ethanol precipitation process of Carthami Flos extract was optimized, considering a noise parameter. The density of the concentrated extract, ethanol concentration, the volume ratio of ethanol to concentrated extract, stirring time after ethanol addition, and refrigeration temperature were selected as critical process parameters (CPPs), using a definitive screening design. The mathematical models among CPPs and evaluation indicators were established. Considering that the refrigeration temperature of industrial ethanol precipitation is often difficult to control with seasonal changes, refrigeration temperature was treated as a noise parameter. A calculation method for the design space in the presence of the noise parameter was proposed. The design space was calculated according to the probability of reaching the standards of evaluation indicators. Controlling parameters within the design space was expected to reduce the influence of noise parameter fluctuations on the quality of the ethanol precipitation supernatant. With more data obtained, the design space was updated. In industry, it is also recommended to adopt a similar idea: that is, continuing to collect industrial data and regularly updating mathematical models, which can further update the design space and make it more stable and reliable.
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Lawrence O Agidike, Godslove I Ebiega, Ovis D Irefu, and Seyi J Fanifosi. "Development of a PID-Controlled Refrigeration System for Reduced Power Consumption." World Journal of Advanced Research and Reviews 24, no. 1 (2024): 2435–49. http://dx.doi.org/10.30574/wjarr.2024.24.1.3143.
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Refrigerator systems are used for food preservation as well as other applications. However, the cost of running the system is high due to rising fuel and electricity prices. Traditionally, these systems are controlled by On/Off controllers. This study proposes the use of a proportional-integral-derivative (PID) controller algorithm to reduce costs for domestic and industrial refrigeration without negatively affecting the system performance. To accomplish this, a physical model was developed, comprising a domestic refrigerator, microcontroller, and MATLAB computer software for analysis. A mathematical model of second-order lead and second-order lag transfer function was also developed for a typical refrigerator system. The physical model was connected, and open-loop temperature-time response data was collected for system modeling. In addition, Data were collected from industries namely Fan Milk Industry and Benue State University Teaching Hospital Mortuary for a robust system analysis. All data sets were imported into MATLAB's system identification toolbox to estimate model parameters. The ultimate gains, frequency, and period were determined for each feedback closed-loop model, allowing the application of Ziegler-Nichols and Tyreus-Luyben PID tuning settings. The closed-loop models were then simulated in MATLAB to evaluate system performance. Simulation results showed that the Tyreus-Luyben model performed better, and offered better temperature response, less undershoot, and faster settling time than the Zeigler-Nichols method. Both PID models outperformed the traditional On/Off controller, with energy consumption reduced to less than one-third of the conventional method. The study concludes that PID controllers are a better alternative to On/Off systems when properly tuned.
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Lawrence, O. Agidike, I. Ebiega Godslove, D. Irefu Ovis, and J. Fanifosi Seyi. "Development of a PID-Controlled Refrigeration System for Reduced Power Consumption." World Journal of Advanced Research and Reviews 24, no. 1 (2024): 2435–49. https://doi.org/10.5281/zenodo.15063139.
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Refrigerator systems are used for food preservation as well as other applications. However, the cost of running the system is high due to rising fuel and electricity prices. Traditionally, these systems are controlled by On/Off controllers. This study proposes the use of a proportional-integral-derivative (PID) controller algorithm to reduce costs for domestic and industrial refrigeration without negatively affecting the system performance. To accomplish this, a physical model was developed, comprising a domestic refrigerator, microcontroller, and MATLAB computer software for analysis. A mathematical model of second-order lead and second-order lag transfer function was also developed for a typical refrigerator system. The physical model was connected, and open-loop temperature-time response data was collected for system modeling. In addition, Data were collected from industries namely Fan Milk Industry and Benue State University Teaching Hospital Mortuary for a robust system analysis. All data sets were imported into MATLAB's system identification toolbox to estimate model parameters. The ultimate gains, frequency, and period were determined for each feedback closed-loop model, allowing the application of Ziegler-Nichols and Tyreus-Luyben PID tuning settings. The closed-loop models were then simulated in MATLAB to evaluate system performance. Simulation results showed that the Tyreus-Luyben model performed better, and offered better temperature response, less undershoot, and faster settling time than the Zeigler-Nichols method. Both PID models outperformed the traditional On/Off controller, with energy consumption reduced to less than one-third of the conventional method. The study concludes that PID controllers are a better alternative to On/Off systems when properly tuned.
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Sadhan, Jyoti Dutta. "Understanding the Fundamentals of Microwave Processing: A Brief Study of Basic Engineering Mathematical Models." Chemical Axis 21, no. 1 (2022): 84. https://doi.org/10.5281/zenodo.6635049.
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The study of foods has been an interesting subject since the history of mankind, be it intentionally or unintentionally. The way humans evolved has a lot to do with what and how humans consumed the food over the course of time. It all began when the early humans discovered fire and used it as a means to cook the raw food which eventually resulted in tastier foods. Overtime, humans became smarter and their fascination with science led them to discover the unknown and unseen principles of nature that surrounds us all. He began using these principles to his own advantage and one of the purposes was to preserve the foods for a long time. This led to the creation of methods such as salting, curing, smoking, roasting, frying, cooling, drying, and many more. Fast forward to present, we now have advance food processing and preservation techniques such as infrared heating, refrigeration, ohmic heating, and microwave heating, among others. Among these unconventional methods of heating, microwave processing is quite popular in the food industry. Hence, it is certainly interesting to study about its principle and learn about the fundamental engineering models that led to the development of the popular heating appliances- the microwave oven (both domestic and industrial).
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Gabibov, Ibrahim Abulfaz, Rabiya Seydulla Nadjafkulieva, and Sevinj Malik Abasova. "MODELING THE HEAT TRANSFER PROCESS IN REFRIGERATION UNITS USED IN THE OIL INDUSTRY." EUREKA: Physics and Engineering 6 (November 30, 2019): 57–62. http://dx.doi.org/10.21303/2461-4262.2019.001056.
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Currently, the main volume of associated petroleum gas production in Azerbaijan is carried out at offshore fields. About 30 % of this volume is used for SOCAR’s own technological needs of the oil company (to maintain the level of oil production). And the rest are transported to onshore facilities and further for processing to a gas processing plant. Subsequently, dry and purified gas is sent through a gas pipeline system for use by the population, or to a network of trunk pipelines for further export. When gas is transferred to the gas lift system and ashore, it is compressed in compressors, as a result of which the temperature of the working agent rises. The latter dramatically reduces the level of operational safety of the entire process. Based on the foregoing, ensuring the required gas quality at the outlet of the compressor unit is an important and urgent task. Currently used in the gas cooling system, shell-and-tube type refrigeration units have several advantages: high heat transfer coefficient, operability in low and high pressure modes, simplicity of design and service. Along with this, these units are distinguished by large dimensions and high metal consumption, noise effect, vibration, etc. A new design of a heat exchanger for cooling associated petroleum gas at the outlet of gas motor compressors is proposed. Based on the modeling of the heat transfer process, mathematical models have been obtained that make it possible to adequately evaluate the cooling process in the proposed refrigeration device.
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Ibrahim, Abulfaz Gabibov, Seydulla Nadjafkulieva Rabiya, and Malik Abasova Sevinj. "MODELING THE HEAT TRANSFER PROCESS IN REFRIGERATION UNITS USED IN THE OIL INDUSTRY." EUREKA: Physics and Engineering 6 (November 30, 2019): 57–62. https://doi.org/10.21303/2461-4262.2019.001056.
Full textAbstract:
Currently, the main volume of associated petroleum gas production in Azerbaijan is carried out at offshore fields. About 30 % of this volume is used for SOCAR’s own technological needs of the oil company (to maintain the level of oil production). And the rest are transported to onshore facilities and further for processing to a gas processing plant. Subsequently, dry and purified gas is sent through a gas pipeline system for use by the population, or to a network of trunk pipelines for further export. When gas is transferred to the gas lift system and ashore, it is compressed in compressors, as a result of which the temperature of the working agent rises. The latter dramatically reduces the level of operational safety of the entire process. Based on the foregoing, ensuring the required gas quality at the outlet of the compressor unit is an important and urgent task. Currently used in the gas cooling system, shell-and-tube type refrigeration units have several advantages: high heat transfer coefficient, operability in low and high pressure modes, simplicity of design and service. Along with this, these units are distinguished by large dimensions and high metal consumption, noise effect, vibration, etc. A new design of a heat exchanger for cooling associated petroleum gas at the outlet of gas motor compressors is proposed. Based on the modeling of the heat transfer process, mathematical models have been obtained that make it possible to adequately evaluate the cooling process in the proposed refrigeration device.
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Никитин, В. В., А. Н. Сучков та А. Г. Белозеров. "Научное обоснование и разработка прогностической модели определения остаточного срока годности упакованного под вакуумом мяса". Food processing industry, № 5 (29 квітня 2025): 48–53. https://doi.org/10.52653/ppi.2025.5.5.008.
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В данной статье проведен комплексный анализ влияния субкриоскопических температур на микробиологические процессы в упакованном под вакуумом, охлажденном и подмороженном мясе свиней. Исследования проводились на образцах M. longissimus dorsi массой 1,5–2,0 кг, выработанных из мяса свиней 2-й категории упитанности. Целью настоящего исследования являлась разработка прогностических моделей, позволяющих оценить остаточный срок годности мясных продуктов в зависимости от условий их хранения. В ходе экспериментов было установлено, что снижение температуры хранения вакуумно-упакованного, охлажденного мяса в диапазоне от 10,0 до минус 2,0 °С приводит к увеличению продолжительности генерации микроорганизмов, что существенно замедляет их метаболическую активность и интенсивность роста. На основании проведенного анализа экспериментальных данных была выявлена корреляционная зависимость между температурными условиями хранения и продолжительностью генерации микроорганизмов. Данная зависимость легла в основу математической модели, предназначенной для прогнозирования остаточного срока годности охлажденного мяса при различных температурных режимах. Для подмороженного мяса также была разработана прогностическая модель, с учетом результатов исследований китайских ученых, на основе которых была установлена зависимость продолжительности генерации микроорганизмов при хранении в области субкриоскопических температур. Данные модели представлены в виде номограмм, позволяющих оценить остаточный срок годности упакованного под вакуумом мяса в зависимости от исходной микробной обсемененности, способа холодильной обработки и температуры хранения. Проверка адекватности разработанных моделей показала высокую степень согласованности с экспериментальными данными, расхождения не превышали 5 %. Таким образом, разработанные прогностические модели позволяют оперативно определять остаточный срок годности мяса, что имеет большое практическое значение для мясоперерабатывающей промышленности. cooling, chilling, storage, vacuum packaging, pork, shelf life, predictive model In this article, a comprehensive analysis of the influence of subcryoscopic temperatures on microbiological processes in vacuum-packed chilled and partially frozen pork is presented. The studies were conducted on samples of M. longissimus dorsi weighing 1,5–2,0 kg, produced from pigs of the second fatness category. The aim of this investigation was to develop predictive models capable of estimating the remaining shelf life of meat products based on their storage conditions. The experiments demonstrated that lowering the storage temperature of vacuum-packed chilled meat from 10,0 to -2,0 °C leads to an increase in the generation time of microorganisms, which significantly slows down their metabolic activity and growth rate. Based on the analysis of the experimental data, a correlation was established between storage temperature conditions and the duration of microbial generation. This relationship formed the basis for a mathematical model designed to predict the remaining shelf life of chilled meat under various temperature regimes. Additionally, a predictive model was developed for partially frozen meat, drawing on the findings of Chinese researchers, which established a dependency between the generation time of microorganisms and storage at subcryoscopic temperatures. Both models are represented as nomograms, facilitating the assessment of the remaining shelf life of vacuum-packed meat based on initial microbial contamination, refrigeration method, and storage temperature. Validation of the developed models confirmed their high accuracy, with discrepancies between predicted and experimental microbial counts not exceeding 5 %. Consequently, these predictive models enable timely determination of meat’s residual shelf life, which is of great practical value for the meat processing industry.
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Ke, Hanbing, Yuansheng Lin, Zhiwu Ke, et al. "Analysis Exploring the Uniformity of Flow Distribution in Multi-Channels for the Application of Printed Circuit Heat Exchangers." Symmetry 12, no. 2 (2020): 314. http://dx.doi.org/10.3390/sym12020314.
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The maldistribution of fluid flow through multi-channels is a critical issue encountered in many areas, such as multi-channel heat exchangers, electronic device cooling, refrigeration and cryogenic devices, air separation and the petrochemical industry. In this paper, the uniformity of flow distribution in a printed circuit heat exchanger (PCHE) is investigated. The flow distribution and resistance characteristics of a PCHE plate are studied with numerical models under different flow distribution cases. The results show that the sudden change in the angle of the fluid at the inlet of the channel can be greatly reduced by using a spreader plate with an equal inner and outer radius. The flow separation of the fluid at the inlet of the channel can also be weakened and the imbalance of flow distribution in the channel can be reduced. Therefore, the flow uniformity can be improved and the pressure loss between the inlet and outlet of PCHEs can be reduced. The flow maldistribution in each PCHE channel can be reduced to ± 0.2%, and the average flow maldistribution in all PCHE channels can be reduced to less than 5% when the number of manifolds reaches nine. The numerical simulation of fluid flow distribution can provide guidance for the subsequent research and the design and development of multi-channel heat exchangers. In summary, the symmetry of the fluid flow in multi-channels for PCHE was analyzed in this work. This work presents the frequently encountered problem of maldistribution of fluid flow in engineering, and the performance promotion leads to symmetrical aspects in both the structure and the physical process.
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Baglivo, Cristina, Paolo Maria Congedo, and Pasquale Antonio Donno. "Analysis of Thermodynamic Cycles of Heat Pumps and Magnetic Refrigerators Using Mathematical Models." Energies 14, no. 4 (2021): 909. http://dx.doi.org/10.3390/en14040909.
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This paper proposes a critical review of the different aspects concerning magnetic refrigeration systems, and performs a detailed analysis of thermodynamic cycles, using mathematical models found in the literature. Langevin’s statistical mechanical theory faithfully describes the physical operation of a refrigeration machine working according to a magnetic Ericsson cycle. Results of mathematical and real experimental models are compared to deduce which best describes the Ericsson cycle. The theoretical data are not perfectly consistent with the experimental data; there is a maximum deviation of about 30%. Numerical and experimental data confirm that very high Coefficient of Performance (COP) values of more than 20 can be achieved. The analysis of the Brayton cycle consisted of finding the mathematical model that considers the irreversibility of these machines. Starting from the thermodynamic properties of magnetocaloric materials based on statistical mechanics, the efficiency of an irreversible Brayton regenerative magnetic refrigeration cycle is studied. Considering the irreversibility in adiabatic transformations, the lower limit of the optimal ratio of two magnetic fields is determined, obtaining a valid optimization criterion for these machines operating according to a Brayton cycle. The results show that the Ericsson cycle achieves a higher Coefficient of Performance than the Brayton cycle, which has a higher cooling capacity as it operates with a larger temperature difference between the magnetocaloric material and source.
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Tršelič, Ivana, and Jurij Avsec. "A CASE STUDY OF EXERGY ANALYSIS OF WASTE HEAT RECOVERY IN REFRIGERATION SYSTEM." Journal of Energy Technology 7, no. 2 (2024): 53–66. https://doi.org/10.18690/jet.7.2.53-66.2014.
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From an energy perspective, refrigeration systems employ a wasteful process; nevertheless, the food industry depends on refrigeration systems. To improve the efficiency of this process, a refrigeration system can be combined with a heating system, by using the waste heat from the condenser of the refrigeration system in the heating system. A case study of the application of a waste heat recovery system is considered in this paper. The conserved energy for three years is calculated, based on the literature, i.e. practical engineering articles. The numbers given are compared with the case study. The economic analysis reveals that the investment in an advanced refrigeration system is returned over a very short time. Two system models are discussed: a refrigeration system with no alternation and a refrigeration system that applies the recovery of waste energy. Exergy analysis has been developed for both models. The analysis shows an increase in the exergy efficiency of the advanced refrigeration system by 2%.
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D.K., Joshi. "Geometrical and Process Parameters Affecting Performance of Ejector Refrigeration System- A Study." Research and Applications of Thermal Engineering 2, no. 3 (2019): 1–8. https://doi.org/10.5281/zenodo.3406941.
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<em>Ejector refrigeration system has been used usually because of its simple configuration with no moving parts. Ejector is crucial part of ejector refrigeration system. Design of ejector sturdily affects the performance of refrigeration system. Available past and present literature and up to date information on in ejector refrigeration system were studied. To analyze the effect of exit nozzle position (NXP) on the ejector performance Some of researches have carried out experiments and paid attention 0n selections of working fluid, mathematical modelling, geometrical and operation conditions of ejector, the enhancement of cooling performance. However, most of the experimental studies which have been done in last few years are still inadequate when compared with simulation and experimental results. </em><em>However, a lot of research work is still required for large-scale applications of ejectors in industry. </em>
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Mani, Kolandavel, Vellappan Selladurai, and Natarajan Murugan. "Experimental investigations with eco-friendly refrigerants using design of experiments technique-mathematical modeling and experimental validation." Thermal Science 18, suppl.2 (2014): 363–74. http://dx.doi.org/10.2298/tsci110805114m.
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In this paper mathematical models were developed using design of experiments technique for the performance prediction of refrigeration system parameters such as refrigerating capacity, power consumption and coefficient of performance. The models developed were checked for their adequacy using F-test. The performances of vapour compression refrigeration system with different refrigerants R12, R134a and R290/R600a were compared. The R290/R600a mixture showed 10.7-23.6% higher coefficient of performance than that with R12 and R134a and it was found that the hydrocarbon mixture with 68% propane and 32% iso-butane could be used as a substitute for R12 and R134a.
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Wang, Lin, Xiao Long Cui, Ying Ying Tan, and Yu Wang. "Study on Energy Efficiency of a Low Temperature Refrigeration System." Applied Mechanics and Materials 71-78 (July 2011): 292–95. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.292.
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Based on conservation of mass, total mass balance equation and component mass balance equation, mathematical models of thermodynamic for the auto cascade refrigeration cycle are established. Thermophysical properties in solving the governing equation are called from the NIST REFPROP7.0. Thermodynamic properties of the auto cascade refrigeration cycle using binary mixtures, namely, R170/R290, R23/R227ea, R116/R134a, R23/R134a, R170/R600a, R170/R600 and R170/R152a as refrigerants is evaluated. R170/R600a is selected for the low temperature refrigeration system, and the influences of cycle mole fraction, compression ratio and evaporating pressure on the cycle performance are analysed.
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Gonçalves, R. S. R., B. Jacob-Furlan, E. C. Kollross, et al. "A MATHEMATICAL MODEL OF AN ABSORPTION REFRIGERATION SYSTEM FOR A REFRIGERATED STORAGE FOR FISHING BOATS." Revista de Engenharia Térmica 21, no. 1 (2022): 25. http://dx.doi.org/10.5380/reterm.v21i1.86688.
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The objective of this paper is to determine if it is possible to refrigerate an area by means of a heat source. Theory determines that an absorption refrigerator can work as a possible solution through a refrigeration fluid. According to it, the system works by the evaporation or condensation of the working fluid. The traditional process consists of using engine fuel to run an electric compressor and by its means achieve refrigeration. That process has its toll on fuel economy and engine efficiency and the refrigeration fluid damages the ozone layer or is based on the transportation of ice previously bought on shore. The technological improvement will be equipped on fishing boats, in order to make the trip last longer due to the possibility of not needing to buy and transport ice and for the purpose of lowering the fishing industry cost. Absorption refrigeration can augment engine efficiency by using heat energy that is normally wasted and the system could reach temperatures of freezing water, meaning that it could be possible to follow Brazilian and international standards. The methodology of this work consists of an energy analysis of an absorption refrigerator, which is the determination of the heat transfer equations on the ammonia evaporator, condenser and exhaust/ammonia. Furthermore, it should be analyzed if it’s possible to determine to which working parameters the system will have an optimum operation. From the mathematical analysis, the system shows that with the equations it is possible to operate an absorption refrigeration based on the exhaust gases of fishing boats. Furthermore, the process can be operated on a wide range of temperatures, being possible to determine according to a few dimensionless parameters to which temperature levels the process of refrigeration shows the best removal of heat.
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Syazin, Ivan Evgen'evich, Gennadiy Ivanovich Kas'yanov, and Aleksandr Valerievich Gukasyan. "Osobennosti teplovogo rascheta porshnevogo kholodil'nogo kompressora." Refrigeration Technology 109, no. 6 (2020): 20–24. http://dx.doi.org/10.17816/rf104046.
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Designing refrigeration reciprocal compressors is a knotty engineering problem. Refrigeration reciprocal compressors differ considerably from the gas ones. To calculate refrigeration reciprocal compressors specially developed mathematical models, which are described in educational and scientific literature, are used. A number of hairy calculations should be performed when designing a compressor. One of them is a thermal calculation intended for determining the baselines of the designed compressor, which will be the basis for following calculations such as gasdynamic, dynamic, strength ones, etc. When performing the thermal calculation, the designer needs to find the optimal values of the diameter and stroke of the piston (basic design indicators), making a start from the calculated data and the indicator diagram. This article considers the main features of the thermal calculation of a refrigeration reciprocal compressor based on a specific example
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Pérez-Gomariz, Mario, Antonio López-Gómez, and Fernando Cerdán-Cartagena. "Artificial Neural Networks as Artificial Intelligence Technique for Energy Saving in Refrigeration Systems—A Review." Clean Technologies 5, no. 1 (2023): 116–36. http://dx.doi.org/10.3390/cleantechnol5010007.
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The refrigeration industry is an energy-intensive sector. Increasing the efficiency of industrial refrigeration systems is crucial for reducing production costs and minimizing CO2 emissions. Optimization of refrigeration systems is often a complex and time-consuming problem. This is where technologies such as big data and artificial intelligence play an important role. Nowadays, smart sensorization and the development of IoT (Internet of Things) make the massive connection of all kinds of devices possible, thereby enabling a new way of data acquisition. In this scenario, refrigeration systems can be measured comprehensively by acquiring large volumes of data in real-time. Then, artificial neural network (ANN) models can use the data to drive autonomous decision-making to build more efficient refrigeration systems.
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Yang, Qichao, Xiaonan Chen, Weikai Chi, Liansheng Li, Guangbin Liu, and Yuanyang Zhao. "Thermodynamic Analysis of an NH3/CO2 Cascade Refrigeration System with Subcooling in the Low-Temperature Circuit Utilizing the Expansion Work." International Journal of Energy Research 2023 (February 27, 2023): 1–17. http://dx.doi.org/10.1155/2023/5987368.
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NH3/CO2 cascade refrigeration system is recognized one of the most promising technologies in low-temperature application. In this paper, a NH3/CO2 cascade refrigeration system with subcooling in low-temperature circuit driven by recovery expansion work has been proposed. The aim of this study is to investigate the proposed cascade refrigeration system compared with conventional cascade refrigeration system. Mathematical models based on energy conservation and exergy balance are established. The selection of different refrigerants in auxiliary subcooling system is discussed. The effects of operating parameters such as the condensation temperature of the low-temperature circuit, evaporation temperature, and expander efficiency on system performance are evaluated. The results show that the coefficient of performance and exergy efficiency of the proposed system are about 7.56% and 7.98% higher than that of conventional cascade refrigeration system. The discharge temperature of NH3 compressor can be significantly reduced by 18.33%. The isentropic efficiency of the expander has a large impact on the system performance.
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Yang, Shutong, Youlei Wang, and Yufei Wang. "Optimization of Cascade Cooling System Based on Lithium Bromide Refrigeration in the Polysilicon Industry." Processes 9, no. 9 (2021): 1681. http://dx.doi.org/10.3390/pr9091681.
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Cascade cooling systems containing different cooling methods (e.g., air cooling, water cooling, refrigerating) are used to satisfy the cooling process of hot streams with large temperature spans. An effective cooling system can significantly save energy and costs. In a cascade cooling system, the heat load distribution between different cooling methods has great impacts on the capital cost and operation cost of the system, but the relative optimization method is not well established. In this work, a cascade cooling system containing waste heat recovery, air cooling, water cooling, absorption refrigeration, and compression refrigeration is proposed. The objective is to find the optimal heat load distribution between different cooling methods with the minimum total annual cost. Aspen Plus and MATLAB were combined to solve the established mathematical optimization model, and the genetic algorithm (GA) in MATLAB was adopted to solve the model. A case study in a polysilicon enterprise was used to illustrate the feasibility and economy of the cascade cooling system. Compared to the base case, which only includes air cooling, water cooling, and compression refrigeration, the cascade cooling system can reduce the total annual cost by USD 931,025·y−1 and save 7,800,820 kWh of electricity per year. It also can recover 3139 kW of low-grade waste heat, and generate and replace a cooling capacity of 2404 kW.
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James, K. A., and R. W. James. "Transient analysis of thermostatic expansion valves for refrigeration system evaporators using mathematical models." Transactions of the Institute of Measurement and Control 9, no. 4 (1987): 198–205. http://dx.doi.org/10.1177/014233128700900406.
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Ge, Y. T., and S. A. Tassou. "Mathematical modelling of supermarket refrigeration systems for design, energy prediction and control." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, no. 2 (2000): 101–14. http://dx.doi.org/10.1243/0957650001538218.
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This paper describes a mathematical model developed to simulate the performance of supermarket refrigeration systems. Such a model can be used for the comparison of different systems and control strategies in terms of their energy and total equivalent warming impact. The model is based on a large number of component models which have been linked together within the TRNSYS environment. Major component models include the compressor, air-cooled condenser, thermostatic expansion valve, display cabinet and control. The overall system model has been validated against monitored data obtained from both a laboratory-based system and a full-scale system in a supermarket in Scotland. The value of the model is illustrated by determining and comparing the effectiveness of head pressure and variable-speed control against fixed head pressure and constant speed control. It is shown that even at summer ambient conditions the system can be operated without problems at much lower head pressures than is done in practice under fixed-pressure control strategies. The use of variable-speed control on one of the compressors can also provide better control of the suction pressure and a substantial (up to 23 per cent) energy savings compared to on-off control.
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Giovannini, Michael, and Marco Lorenzini. "Numerical Model of an Evaporative Condenser for the Food Refrigeration Industry." Journal of Physics: Conference Series 2177, no. 1 (2022): 012009. http://dx.doi.org/10.1088/1742-6596/2177/1/012009.
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Abstract Evaporative condensers play a key role in refrigeration plants for industrial applications, as they are needed to dispose of the thermal and electric power required by the process. Modelling them as lumped capacitance systems is very expedient when trying to simulate e. g. the steady-state and dynamic behaviour of the whole refrigeration plant, but at the expenses of loss of information and often oversimplifying assumptions. This paper analyses two models for heat and mass transfer in cooling equipment, Poppe’s and its earlier, simpler version, Merkel’s. The two approaches are applied to describe the transport phenomena in an evaporative condenser and the predicted cooling power compared to the data declared by the manufacturer under certain operating conditions. It is demonstrated that predictions are accurate within less than 10%.
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Liu, Yan Ling, Ling Qun Wang, and Zai Zhong Xia. "Design and Performance Study of a Novel Refrigeration System." Advanced Materials Research 354-355 (October 2011): 819–27. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.819.
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In order to solve the problems of pressure drop and leakage in the refrigerant circuit, a novel continuous adsorption system suited to use low heat source (75-85 oC) was designed and set up. To analyze and compare with the conventional system to reveal the similarity and difference, this paper sets up the mathematical models for these two systems. The adsorbers, condensers and evaporators in these two systems are exactly the same and the two systems are compared by working at the identical conditions, which is not feasible in real experimental lab. All the parameters and models used in this calculation are based on experimental results. Analysis demonstrates that the two kinds of system have very close performances, that is, the novel system has a relatively higher cooling capacity while the conventional system has a relatively higher COP.
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Zhao, Shibo, Yonghui Zhang, Yunqi Nie, Pengyu Qu, and Wenqiang Sun. "Performance of an internet data center refrigeration system using an evaporative cooler." E3S Web of Conferences 194 (2020): 01027. http://dx.doi.org/10.1051/e3sconf/202019401027.
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The traditional refrigeration method of internet data center (IDC) is mostly air refrigeration, which has undesired cooling effect and high power consumption. This study addresses this problem and proposes an evaporative air cooler (EAC) suitable for IDC. Given the high specific heat capacity of water, the evaporative condensing coil and spray device are added to the evaporative cooler to enhance the heat transfer effect. Heat and mass transfer mathematical models are established to analyze the heat transfer performance. The mathematical model is used to simulate the profile of the heat and mass transfer coefficient of the EAC with the amount of spray water and air flow. The results show that when the air flow changes from 10 to 20 kg/s, the air equivalent heat transfer coefficient increases by about 41%. When the air flow rate is 20 kg/s and the spray water volume is 0.00124 kg/(mꞏs), the total heat transfer coefficient is increased by about 308% compared with the case without spray water.
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Poletaykin, V. F., and G. N. Plesovskikh. "Mathematical models of timber loader motion." Traktory i sel hozmashiny 80, no. 11 (2013): 24–26. http://dx.doi.org/10.17816/0321-4443-65728.
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Sitotaw, Natnale. "Energy and Exergy Analysis of Single Effect Water-LiBr Vapour Absorption Refrigeration System." International Journal of Advanced Science Computing and Engineering 4, no. 3 (2022): 175–87. http://dx.doi.org/10.30630/ijasce.4.3.94.
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Vapor absorption refrigeration system (VARS) is one of the emerging technology in thermal-driven refrigeration systems and has too many benefits in comparison with another cooling system as their performance is good and the cost is low. Different mathematical models of various complexities have been developed for performance analysis, optimization, and design of such systems. In this study energy and exergy of a single effect LiBr vapor absorption refrigeration system is analyzed with different mathematical model developed so far. The effect of varying the temperature for each component of the system on the coefficient of performance (COP) and exergetic efficiency (COPex) is briefly discussed. The results show that increasing generator temperature from 86oc to 102oc for constant refrigerant mass flow rate causes COP of the system to increase, due to the decrease in circulation ratio. In another case, increasing the evaporator temperature from 2oc to 14oc for a constant temperature input of the generator has a positive effect on both the first and second law efficiency of the VARS as the load on the generator decrease. From the result, it can also be concluded that increasing absorber temperature has a negative impact on both COP and exergetic efficiency of VARS.
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Sitotaw, Natnale. "Energy and Exergy Analysis of Single Effect Water-LiBr Vapour Absorption Refrigeration System." International Journal of Advanced Science Computing and Engineering 4, no. 3 (2022): 175–87. http://dx.doi.org/10.62527/ijasce.4.3.94.
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Vapor absorption refrigeration system (VARS) is one of the emerging technology in thermal-driven refrigeration systems and has too many benefits in comparison with another cooling system as their performance is good and the cost is low. Different mathematical models of various complexities have been developed for performance analysis, optimization, and design of such systems. In this study energy and exergy of a single effect LiBr vapor absorption refrigeration system is analyzed with different mathematical model developed so far. The effect of varying the temperature for each component of the system on the coefficient of performance (COP) and exergetic efficiency (COPex) is briefly discussed. The results show that increasing generator temperature from 86oc to 102oc for constant refrigerant mass flow rate causes COP of the system to increase, due to the decrease in circulation ratio. In another case, increasing the evaporator temperature from 2oc to 14oc for a constant temperature input of the generator has a positive effect on both the first and second law efficiency of the VARS as the load on the generator decrease. From the result, it can also be concluded that increasing absorber temperature has a negative impact on both COP and exergetic efficiency of VARS.
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Minaev, V. A., V. M. Pizengolts, A. O. Faddeev, A. Y. Bystryakov, E. V. Savenkova, and E. V. Kruglikova. "Modern information and mathematical models in construction industry." E3S Web of Conferences 116 (2019): 00051. http://dx.doi.org/10.1051/e3sconf/201911600051.
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Building information modelling (BIM) – new technology of construction object information maintenance. It allows specifying influence of changes and risks made in it (including geodynamic) at all stages of lifecycle. Objects include products, building equipment, technological platform, the building, engineering, transportation networks and systems of building communication. The model expands possibilities of innovative technologies implementation, allowing creating reasoned economic decisions.
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Liu, Shi Qiang, and Erhan Kozan. "Integration of mathematical models for ore mining industry." International Journal of Systems Science: Operations & Logistics 6, no. 1 (2017): 55–68. http://dx.doi.org/10.1080/23302674.2017.1344330.
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Kumar, Naresh, and Balraj Singh. "Forecast of Indian Automobile Industry Using Mathematical Models." Paradigm 7, no. 2 (2003): 105–16. http://dx.doi.org/10.1177/0971890720030207.
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Izquierdo, J., R. Pérez, and P. L. Iglesias. "Mathematical models and methods in the water industry." Mathematical and Computer Modelling 39, no. 11-12 (2004): 1353–74. http://dx.doi.org/10.1016/j.mcm.2004.06.012.
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Estrada-Flores, S., D. J. Cleland, A. C. Cleland, and R. W. James. "Simulation of transient behaviour in refrigeration plant pressure vessels: mathematical models and experimental validation." International Journal of Refrigeration 26, no. 2 (2003): 170–79. http://dx.doi.org/10.1016/s0140-7007(02)00081-6.
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Huang, Yanjun, Amir Khajepour, Farshid Bagheri, and Majid Bahrami. "Modelling and optimal energy-saving control of automotive air-conditioning and refrigeration systems." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 3 (2016): 291–309. http://dx.doi.org/10.1177/0954407016636978.
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Air-conditioning and refrigeration systems are extensively adopted in homes, industry and vehicles. An important step in achieving a better performance and a higher energy efficiency for air-conditioning and refrigeration systems is a control-based model and a suitable control strategy. As a result, a dynamic model based on the moving-boundary and lumped-parameter method is developed in this paper. Unlike existing models, the proposed model lumps the effects of the fins into two equivalent parameters without adding any complexity and considers the effect produced by the superheated section of the condenser, resulting in a model that is not only simpler but also more accurate than the existing models. In addition, a model predictive controller is designed on the basis of the proposed model to enhance the energy efficiency of the air-conditioning and refrigeration systems. Simulations and experimental results are presented to demonstrate the accuracy of the model. The experiments show that an energy saving of about 8% can be achieved by using the proposed model predictive controller compared with the conventional on–off controller under the examined scenario. The better performance of the proposed controller requires electrification of the automotive air-conditioning and refrigeration systems so as to eliminate the idling caused by running the air-conditioning and refrigeration systems when a vehicle stops.
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Liu, Yan Ling, Xue Zeng Shi, and Yuan Yu. "Mathematical Analysis on a Special Adsorption Refrigeration System Suitable for Solar Energy System." Advanced Materials Research 953-954 (June 2014): 119–22. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.119.
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s. In this paper, a new adsorption refrigeration system is designed and calculated. In this system, there are two beds, two condensers and two evaporators. The working principle is explained and specified in this paper. And mathematical models are also set up and through calculation, the system performance is analyzed and evaluated.Theory study results demonstrate that the new system nearly has the same cooling capacity as conventional system and this kind of system can be adopted in actual use.
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Dumitrascu, Gheorghe, Michel Feidt, and Stefan Grigorean. "Closed Irreversible Cycles Analysis Based on Finite Physical Dimensions Thermodynamics." Proceedings 58, no. 1 (2020): 37. http://dx.doi.org/10.3390/wef-06905.
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The paper develops generalizing entropic approaches of irreversible closed cycles. The mathematical models of the irreversible engines (basic, with internal regeneration of the heat, cogeneration units) and of the refrigeration cycles were applied to four possible operating irreversible trigeneration cycles. The models involve the reference entropy, the number of internal irreversibility, the thermal conductance inventory, the proper temperatures of external heat reservoirs unifying the first law of thermodynamics and the linear heat transfer law, the mean log temperature differences, and four possible operational constraints, i.e., constant heat input, constant power, constant energy efficiency and constant reference entropy. The reference entropy is always the entropy variation rate of the working fluid during the reversible heat input process. The amount of internal irreversibility allows the evaluation of the heat output via the ratio of overall internal irreversible entropy generation and the reference entropy. The operational constraints allow the replacement of the reference entropy function of the finite physical dimension parameters, i.e., mean log temperature differences, thermal conductance inventory, and the proper external heat reservoir temperatures. The paper presents initially the number of internal irreversibility and the energy efficiency equations for engine and refrigeration cycles. At the limit, i.e., endoreversibility, we can re-obtain the endoreversible energy efficiency equation. The second part develops the influences between the imposed operational constraint and the finite physical dimensions parameters for the basic irreversible cycle. The third part is applying the mathematical models to four possible standalone trigeneration cycles. It was assumed that there are the required consumers of the all useful heat delivered by the trigeneration system. The design of trigeneration system must know the ratio of refrigeration rate to power, e.g., engine shaft power or useful power delivered directly to power consumers. The final discussions and conclusions emphasize the novelties and the complexity of interconnected irreversible trigeneration systems design/optimization.
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Al-Hemeri, Dr Shurooq Talib, Dr Mumtaz A. Yousif, and Dr Ahmed M. AL Barifcani. "Optimization of Ethylene Refrigeration System Using Genetic Algorithms Method." Journal of Petroleum Research and Studies 7, no. 1 (2021): 1–37. http://dx.doi.org/10.52716/jprs.v7i1.157.
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Ethylene refrigeration for gases separation at low temperature and high pressure for olefin production is an important technique in the chemical industry. Since small changes in the operating conditions of such a process can have a significant influence on its economics, optimization is desirable. The present work was aimed to propose and establish a mathematical model for the ethylene refrigeration system of the ethylene plant in Basrah petrochemical complex NO.1 (PC1) and reformulated as a geometric programming problem using Visual Basic for predicting:- (overall efficiency of the ethylene refrigeration system {% }and percent of energy saving %E). Through the formulated model shaft work consumption by the centrifugal compressor, refrigeration effect and coefficient of performance of the system were obtained and other parameters concerning the system. The results of simulation showed a good agreement with the manufacturer manual.In this study the effect of four factors as independent variables on the overall refrigeration system efficiency and percent of energy saving were studied ;evaporator low pressure (PL) in the range of (1-3)bar ,compressor discharge high pressure (Ph) in the range of ( 28-32)bar ,condenser degree of sub-cool temperature (Tsub-D) in the range of (6-22)0C and evaporator degree of superheat temperature (Tsup-D) in the range of (1-5)0C. And the optimum conditions that aimed to minimize the thermodynamic irreversibility i.e (maximize overall refrigeration system efficiency) and also lower operating cost i.e (maximize percent of energy saving) evaporator low pressure (PL) (2.8 bar), compressor discharge high pressure (Ph) (28.7 bar), condenser degree of sub-cool temperature (Tsub-D) (190C), and evaporator degree of superheat temperature (Tsup-D) (3.40C). At these conditions the overall refrigeration system efficiency is (81.8%) and percent of energy saving is 51.18% with respect to conditions in the factory.
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Khenien, A., A. Benattayallah, and G. Tabor. "CFD Simulation of an Industrial Spiral Refrigeration System." Energies 12, no. 17 (2019): 3358. http://dx.doi.org/10.3390/en12173358.
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In the food industry, heating and cooling are key processes where CFD can play an important role in improving quality, productivity and reducing energy costs. Cooling products after baking is crucial for storage and transportation; the product has to be cooled efficiently to a specified temperature (often to fulfill regulatory requirements) whilst preserving its quality. This study involves the analysis of spiral cooling refrigerators used in cooling food products, in this case, Cornish Pasties. Three separate sets of CFD models were developed and validated against experimental data taken in the laboratory and measurements taken in use in industry. In the first set of models a full CFD model was developed of a refrigeration spiral including the pasties, and used to study the heat transfer from the products to the air. Further simulations were carried out on individual pasties to explore the pasty cooling and heat transfer to the air in more detail, with the pasty geometry being determined from MRI scans. In the final set of simulations, Image Based Meshing (IBM) was used to determine the interior structure of the pasty and develop a full heat conduction model of the interior, which was compared with separate laboratory experiments using jets of cold air to cool the pasty. In all cases, good agreement was obtained between the CFD results and experimental data, whilst the CFD simulations provide valuable information about the air flows and cooling in the industrial system.
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Dantas, Tarcísio Soares Siqueira, Ivan Carlos Franco, Ana Maria Frattini Fileti, and Flávio Vasconcelos da Silva. "Nonlinear System Identification of a Refrigeration System." International Journal of Air-Conditioning and Refrigeration 24, no. 04 (2016): 1650024. http://dx.doi.org/10.1142/s2010132516500243.
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Applications of advanced control algorithms are important in the refrigeration field to achieve low-energy costs and accurate set-point tracking. However, the designing and tuning of control systems depend on dynamic mathematical models. Approaches like analytical modeling can be time-consuming because they usually lead to a large number of differential equations with unknown parameters. In this work, the application of system identification with the fast recursive orthogonal least square (FROLS) algorithm is proposed as an alternative to analytical modeling to develop a process dynamic model. The evaporating temperature (EVT), condensing temperature (CDT) and useful superheat (USH) are the outputs of interest for this system; covariance analysis of the candidate inputs shows that the model should be single-input–single-output (SISO). Good simulation results are obtained with two different validation data, with average output errors of 0.0343 (EVT model), 0.0079 (CDT model) and 0.1578 (USH model) for one of the datasets, showing that this algorithm is a valid alternative for modeling refrigeration systems.
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Zhang, Wenyuan, Zhengrong Shi, and Tao Zhang. "Design of A Mobile Photovoltaic Direct-drive Refrigeration Compartment." Journal of Physics: Conference Series 2503, no. 1 (2023): 012034. http://dx.doi.org/10.1088/1742-6596/2503/1/012034.
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Abstract The large consumption of nonrenewable energy has caused energy shortages and environmental climate problems, and improper food storage has caused a large amount of food waste. To solve the problem of energy shortage and waste in grain transportation, a photovoltaic direct-drive refrigeration compartment based on apple transportation is designed. The design adopts a 15-foot refrigeration compartment and uses lightweight crystalline silicon PV modules to reduce the overall weight of the refrigeration compartment. According to the room size, eight parallel PV modules are selected for power generation. In conjunction with the PV modules, the rated power of the chosen compressor is 2.6 kW. Based on the storage conditions of apples, the design storage temperature is 0 °C, and HM-EO-2 is used as the refrigerant for cold storage. According to the transportation requirements of apples, the designed cold storage capacity of the cryogen should meet the 48h cold load. The mathematical models of the cold load of refrigeration compartments, refrigerant storage, and solar irradiation are established, which verify that the refrigeration system is correctly selected, and the critical parameters of the cold storage system are designed. It is calculated that the maximum hourly cold load and the daily total cold load of the refrigeration compartment are taken on June 29. The maximum hourly load is 1.355 kW, and the daily total load is 16.781 kW. The selected compressor can meet the real cooling demand.
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Zhuk, Tetyana. "Mathematical Models of Reinsurance." Mohyla Mathematical Journal 3 (January 29, 2021): 31–37. http://dx.doi.org/10.18523/2617-70803202031-37.
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Insurance provides financial security and protection of the independence of the insured person. Its principles are quite simple: insurance protects investments, life and property. You regularly pay a certain amount of money in exchange for a guarantee that in case of unforeseen circumstances (accident, illness, death, property damage) the insurance company will protect you in the form of financial compensation.Reinsurance, in turn, has a significant impact on ensuring the financial stability of the insurer. Because for each type of insurance there is a possibility of large and very large risks that one insurance company can not fully assume. In the case of a portfolio with very high risks, the company may limit their acceptance, or give part of the reinsurance. The choice of path depends entirely on the company’s policy and type of insurance.This paper considers the main types of reinsurance and their mathematical models. An analysis of the probability of bankruptcy and the optimal use of a particular type of reinsurance are provided.There are also some examples and main results of research on this topic. After all, today the insurance industry is actively gaining popularity both in Ukraine and around the world. Accordingly, with a lot of competition, every insurer wants to get the maximum profit with minimal e↵ort.
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LESLIE, F. M., and I. W. STEWART. "Editorial. Mathematical models of liquid crystals." European Journal of Applied Mathematics 8, no. 3 (1997): 251–52. http://dx.doi.org/10.1017/s0956792597003082.
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A symposium held in Durham in July 1995 brought together an international collection of key mathematicians, theoretical physicists and experimentalists in the areas of liquid crystals and polymeric systems. Many of the participants met together for the first time, and the symposium stimulated new collaborative interactions among applied mathematicians and others who, prior to this meeting, were working separately on either liquid crystals or polymer fluids. The symposium also enhanced further interchanges of ideas between industry and academia. The flavour of this meeting is captured by the contents of this special issue which resulted from presentations given by invited speakers.
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Ansari, F. A. "Simplified and Accurate Mathematical Model for the Analysis of Heat and Moisture Transfer From Food Commodities." Journal of Heat Transfer 120, no. 2 (1998): 530–33. http://dx.doi.org/10.1115/1.2824285.
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The present paper deals with a simple and accurate mathematical model for making reliable heat and mass transfer analyses from high-water–content solids when exposed to a cold air stream. Such physical situations are encountered in the refrigeration industry during air blast cooling of food commodities. The concept of enthalpy potential has been used to develop a simple linear surface boundary condition equation. This equation accounts for the cooling effect due to sensible convective heat transfer as well as the latent cooling effect due to produce desiccation. Investigations on ten fresh samples each of ripe tomato and cucumber established that there is a good agreement between the computed temperatures from the proposed model and the experimentally measured values.
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Semenov, Alexander Evgenyevich, and Aleksander Ivanovich Andreev. "Optimization of operating modes of ship refrigeration plant with artificial cold accumulator." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2023, no. 3 (2023): 65–73. http://dx.doi.org/10.24143/2073-1574-2023-3-65-73.
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The ways of optimizing the operation of a refrigeration unit for fishing and refrigerated vessels with the additional inclusion of artificial cold storage devices are investigated. For this purpose, a new technology of cold storage has been developed on the basis of a refrigerating machine with direct contact between media and ice production. The refrigerant RC318 was taken as freon which does not form crystalline hydrates. Based on this, the optimization of the operation of a single-stage refrigeration machine was carried out using the Lagrange multiplier method for the target function of energy consumption, calculated by reducing the exergy flow in the system. The data obtained show the relevance and prospects of using cold accumulation on ships to reduce energy costs for the operation of refrigeration equipment and increase the autonomy of fishing vessels. Optimization according to the given method leads to two modes of operation of the refrigerating machine, as the most optimally beneficial in terms of operating conditions during the generation of cold. Optimization was carried out for two schemes for including a cold accumulator in the cold supply system. The proposed optimization methods make it possible to reduce the energy consumption of refrigeration units to the level of design loads, and to compensate for peak loads with the help of cold from batteries. Further research in this matter is aimed at reducing the size of the battery, increasing its energy efficiency and developing recommendations for inclusion in the general schemes of ship refrigeration plants based on mathematical optimization models and field experiments. It also plans to further improve the methods of cold accumulation based on ice generation with direct contact of media inside refrigeration units.
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Turlakova, S. S., R. B. Reznikov та S. V. Balabanov. "Economіc and Mathematіcal Modelіng of Fіscal Stіmulatіon of the Development of Smart-Іndustry". Herald of the Economic Sciences of Ukraine, № 2(45) (2023): 49–62. http://dx.doi.org/10.37405/10.37405/1729-7206.2023.2(45).49-62.
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Objective: The study focuses on analyzing contemporary economic-mathematical models of fiscal stimulation for the development of smart industry. Primary attention is dedicated to systematizing existing approaches, identifying their shortcomings, and determining potential directions for their improvement. Adapting existing models to the specifics of the national economy of Ukraine, as well as considering the contemporary challenges of globalization and digital transformation, represents a key aspect of the research. Tasks: Several key tasks have been defined within the study. First and foremost is the analysis of existing economic-mathematical models of fiscal stimulation, evaluating their strengths and weaknesses. The second task is to identify the main factors influencing the development of smart industry, and to develop a conceptual model of financial stimulation for its further advancement. The third task involves developing recommendations for improving the financial support of smart industry in Ukraine. Subject: The subject of the study encompasses economic-mathematical models applied for analyzing and stimulating the development of smart industry. The study conducts a detailed analysis of various approaches, their application, and effectiveness. Methods: The research employs an analytical literature review, comparative analysis, as well as the application of economic-mathematical modeling. These methods allow for an evaluation of the current state of affairs in the field and the development of well-founded recommendations for improving existing approaches. Main Results: The findings of the study indicate the necessity to adapt the majority of existing models to the conditions of the contemporary Ukrainian economy. Key directions for improving these models have been identified, particularly through considering the specifics of national development and incorporating innovative factors. Practical recommendations have been developed, which can be utilized to enhance fiscal stimulation for the development of smart industry. Conclusions: The application of economic-mathematical models serves as a vital tool for analyzing the impact of fiscal stimulation on smart industry. It enables the adaptation of existing approaches to the specifics of the national economy and consideration of the peculiarities of contemporary conditions. Overall, the research contributes to understanding how economic-mathematical modeling can be used to support and stimulate the development of smart industry, thereby ensuring sustainable economic growth and innovative development.
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Kandalova, Marina. "Statistical evaluation of production indicators." E3S Web of Conferences 371 (2023): 05051. http://dx.doi.org/10.1051/e3sconf/202337105051.
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The industry is characterized by a rather complex technological cycle and has many economic entities involved in the implementation of the products of this industry. Under these conditions, the construction of an optimal management system of a food enterprise cannot be carried out without the presence of formed practical analysis models that contribute to the identification of patterns of their functioning. The use of statistical data in it, which allow us to take into account laws and established trends in the development of forecasts for the development of various industries. Mathematical analysis of statistical data in industry is based on various models and methods, among which the advantage is given to economic and mathematical or simulation modeling. By means of traditional mathematical models during static observation, trends and forecasts of the development of the industry are built, the study of which is aimed at this article.
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OVCHYNNIKOVA, OLENA, and GRAZYNA KACICKA. "TREND MODELS OF FOREST INDUSTRY INDICATORS." MODELING THE DEVELOPMENT OF THE ECONOMIC SYSTEMS 2, no. 2 (2021): 25–32. http://dx.doi.org/10.31891/mdes/2021-2-4.
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The article analyzes the main indicators of the forest industry of Ukraine and Khmelnytsky region. The state of timber harvesting by types of products is shown, it is noted that since 2017 there is no financing of the forest industry by the state, so forestries have to manage independently from their own sources. The paper considers the problem of modeling the indicators of the forest industry of the regions with the help of economic and mathematical methods and models. Trend models have been chosen as a research tool, with the help of which the equations of power, logistic, exponential dependences and polynomials of the second and third degrees are obtained. The constructed models are evaluated according to the criteria of determination and the forecast values for the following periods are determined. The results of calculations can be used in management decision-making systems as a source of data for further calculations. The obtained forecasts of forest industry indicators showed the importance of investing in the forest industry. Preservation, rational use and increase of resources of the forest treasury - so it is possible to define the main tasks facing the forestry of Ukraine. The issue of reforestation, creation of forest plantations in the volumes exceeding fellings, improvement of their qualitative structure and productivity remains paramount in the importance and urgency. Given the current situation in the country's forestry and in order to solve the problem of ecologically balanced forest management as a factor of sustainable socio-economic development, it is necessary to apply a comprehensive approach based on the use of economic and mathematical methods and models. This allows you to take into account technical, economic, environmental, organizational, social and other aspects of management, as well as see their relationship. One of the means of balanced management is modeling and forecasting trends in the main indicators of the forest industry both at the regional level and in the country as a whole.
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Uvaliуeva, I., S. Belginova, and A. smukhamedova. "MATHEMATICAL AND COMPUTER MODELING IN THE PHARMACEUTICAL INDUSTRY." BULLETIN of D. Serikbayev EKTU 2 (June 30, 2023): 248–56. http://dx.doi.org/10.51885/1561-4212_2023_2_248.
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Mathematical and computer modeling is one of the most powerful tools for analyzing and designing various technological processes, including the pharmacological process, which allows you to save resources and prevent many risks in the production of innovative medicines. The use of such models is especially necessary during the transition from the research to the production stage of the release of medicines. This article discusses the techno-logical process of drug production using the example of the drug "Atenolol". On the basis of certain parameters of this drug, a mathematical model is built, where a complex indicator of the assessment of the quality of the technolog-ical process is calculated. When calculating the complex quality indicator, the following main parameters are used: drying temperature, drying time, drug formation coefficient, humidity, strength, decomposition, grinding, integrity. The mathematical and computer models created as a result of the research will improve the efficiency of quality management of the technological process of manufacturing medicines.
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Dandoutiya, Bhrant, and Arvind Kumar. "Comparison of mathematical models to estimate the thermal conductivity of titanium oxide-water based nanofluid: A review." Thermal Science, no. 00 (2021): 224. http://dx.doi.org/10.2298/tsci201026224d.
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Heat transfer is a desirable phenomenon in many industries such as in refrigeration, transportation, power generation, cell preservation, incubator, metallurgy and material processing, health services, etc. Different types of fluids like water, oil, ethylene glycol etc are being used as a heat transfer medium. Water is a commonly used as working fluid for transfer of heat. Nanofluids are developed by adding nano sized particle(s) in existing fluid to improve the heat transfer rate. Thermal conductivity of the nanofluid is an important parameter in estimation of heat transfer rate. Different types of mathematical models were developed by various investigators to predict the thermal conductivity of the nanofluids. In this review paper,the theoretical and mathematical model(s) have been compared to predict the thermal conductivity of nanofluids. The experimental data have been collected from literature and compared with Maxwell model, Hamilton and crosser(H-C) model, Maxwell-Garnetts(MG) model, Pak cho model, Timofeeva et al. model, Li and Peterson model, Bhattacharya et al. model respectively in detail. It has been observed that the prediction wih the help of the mathematical models is good when the value of volume fraction was less than 0.01.
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Muhammad, Hafiz Ali, Hafiz Muhammad Abdullah, Zabdur Rehman, et al. "Numerical Modeling of Ejector and Development of Improved Methods for the Design of Ejector-Assisted Refrigeration System." Energies 13, no. 21 (2020): 5835. http://dx.doi.org/10.3390/en13215835.
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An ejector is a simple mechanical device that can be integrated with power generation or the refrigeration cycle to enhance their performance. Owing to the complex flow behavior in the ejector, the performance prediction of the ejector is done by numerical simulations. However, to evaluate the performance of an ejector integrated power cycle or refrigeration cycle, the need for simpler and more reliable thermodynamic models to estimate the performance of the ejector persists. This research, therefore, aims at developing a single mathematical correlation that can predict the ejector performance with reasonable accuracy. The proposed correlation relates the entrainment ratio and the pressure rise across the ejector to the area ratio and the mass flow rate of the primary flow. R141b is selected as the ejector refrigerant, and the results obtained through the proposed correlation are validated through numerical solutions. The comparison between the analytical and numerical with experimental results provided an error of less than 8.4% and 4.29%, respectively.
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Di Mattia, Edoardo, Agostino Gambarotta, Mirko Morini, and Costanza Saletti. "Application of modelling approaches of twin-screw compressors: thermodynamic investigation and reduced-order model identification." E3S Web of Conferences 312 (2021): 05001. http://dx.doi.org/10.1051/e3sconf/202131205001.
Full textAbstract:
Refrigeration is an essential part of the food chain. It is used in all stages of the chain, from industrial food processing to final consumption at home. In these processes, mechanical refrigeration technologies are employed, where compressors increase gas pressure from evaporation to condensation. In industrial refrigeration systems, twin-screw compressors represent the most widely used technology. A detailed mathematical model of a twin-screw compressor has been developed in Simulink® using differential equations for energy and mass balances to simulate the compression cycle that includes suction, compression and discharge phases. Gas pressure and enthalpy can be calculated as time functions during the cycle. However, the computational times obtained limit the possibility to extend the use of the model in the development of control strategies for the whole refrigeration plant in its real operating conditions. Therefore, the detailed model has been used to train a simplified model developed in Matlab®: the simulated mass flow rate, shaft power and the fluid discharge temperature have been employed to identify several geometrical and thermodynamic parameters of the simplified model. The latter relies on non-linear algebraic equations and, thus, requires a very short computational time. A limited performance dataset has been used to train the model, and a different dataset to test it: the results of the models have been compared, and small errors in mass flow rate, shaft power and fluid discharge temperature have been observed.
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Haida, Michal, Rafal Fingas, Wojciech Szwajnoch, et al. "An Object-Oriented R744 Two-Phase Ejector Reduced-Order Model for Dynamic Simulations." Energies 12, no. 7 (2019): 1282. http://dx.doi.org/10.3390/en12071282.
Full textAbstract:
The object-oriented two-phase ejector hybrid reduced-order model (ROM) was developed for dynamic simulation of the R744 refrigeration system. OpenModelica software was used to evaluate the system’s performance. Moreover, the hybrid ROM results were compared to the results given by the non-dimensional and one-dimensional mathematical approaches of the R744 two-phase ejector. Accuracy of all three ejector models was defined through a validation procedure for the experimental results. Finally, the dynamic simulation of the hybrid ROM ejector model integrated with the R744 refrigeration system was presented based on the summer campaign at three different climate zones: Mediterranean, South American and South Asian. The hybrid ROM obtained the best prediction of ejector mass flow rates as compared with other ejector models under subcritical and transcritical operating conditions. The dynamic simulations of the R744 ejector-based system indicated the ejector efficiency variations and the best efficiency at the investigated climate zones. The coefficient of performance (COP) varied from 2.5 to 4.0 according to different ambient conditions. The pressure ratio of 1.15 allowed a more stabilised system during the test campaign with an ejector efficiency from 20% to over 30%.