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1
Cirera, Josep, Jesus A. Carino, Daniel Zurita i Juan A. Ortega. "A Data-Driven-Based Industrial Refrigeration Optimization Method Considering Demand Forecasting". Processes 8, nr 5 (21.05.2020): 617. http://dx.doi.org/10.3390/pr8050617.
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One of the main concerns of industry is energy efficiency, in which the paradigm of Industry 4.0 opens new possibilities by facing optimization approaches using data-driven methodologies. In this regard, increasing the efficiency of industrial refrigeration systems is an important challenge, since this type of process consume a huge amount of electricity that can be reduced with an optimal compressor configuration. In this paper, a novel data-driven methodology is presented, which employs self-organizing maps (SOM) and multi-layer perceptron (MLP) to deal with the (PLR) issue of refrigeration systems. The proposed methodology takes into account the variables that influence the system performance to develop a discrete model of the operating conditions. The aforementioned model is used to find the best PLR of the compressors for each operating condition of the system. Furthermore, to overcome the limitations of the historical performance, various scenarios are artificially created to find near-optimal PLR setpoints in each operation condition. Finally, the proposed method employs a forecasting strategy to manage the compressor switching situations. Thus, undesirable starts and stops of the machine are avoided, preserving its remaining useful life and being more efficient. An experimental validation in a real industrial system is performed in order to validate the suitability and the performance of the methodology. The proposed methodology improves refrigeration system efficiency up to 8%, depending on the operating conditions. The results obtained validates the feasibility of applying data-driven techniques for the optimal control of refrigeration system compressors to increase its efficiency.
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Zhang, Liang, Huawei Zhang, Qiyu Chen i Danfeng Long. "A Mathematical Approach for Sound Insulation Characteristics and Cost Optimization of Double-Layer Composite Structures". Journal of Composites Science 7, nr 3 (9.03.2023): 110. http://dx.doi.org/10.3390/jcs7030110.
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The compressor is the primary source of noise in a refrigeration system. Most compressors are wrapped with multi-layer sound insulation cotton for noise reduction and sound insulation. We explore the sound insulation law of different polyvinyl chloride thicknesses and non-woven fibers. Polyvinyl chloride with varying thicknesses and non-woven fibers are then combined by bonding to study the sound insulation characteristics of a two-layer composite structure. A sound insulation prediction model is established using the multi-parameter nonlinear regression method. An optimal cost mathematical model is established based on experimental and mathematical methods that can quickly determine the optimal cost scheme for different designs with the same effect.
3
Negara, I. Putu Sastra, i Ni Ketut Rusminingsih. "The Analysis of the Use of Intercooler on a Multi Stage Cold Storage Simulator Toward the Compressor Work". Logic : Jurnal Rancang Bangun dan Teknologi 22, nr 2 (30.07.2022): 132–39. http://dx.doi.org/10.31940/logic.v22i2.132-139.
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Multistage type cold storage is a refrigeration machine required in an industry because it functions to store food products for a long time. Bali, as a world tourist destination, will rely heavily on this cooling system in preparing services for tourists, especially in the food and beverage sector. Multistage type cold storage is designed to reach the evaporator temperature below -30oC thus the used compressor performance must be able to produce maximum refrigeration effect. Two compressors placed in succession or connected in series complete this cold storage system, which is expected to achieve higher operating pressures. The temperature occurring due to the pressure increase on the second compressor will be anticipated by installing an intercooler aiming at preventing excessive heat or over heat during the compression. The extent to which the important role of the intercooler as a stabilizer of operating temperature in this cooling cycle will be shown in its working cycle with a Mollier diagram (P-h diagram). The data obtained during the operation of the multistage type cold storage is then transferred to the P-h diagram of R134A to determine the cycle diagram and the enthalpy which then determines the amount of COP, the maximum temperature achieved by the system, and its energy requirements. The calculation results obtained using the intercooler COP is 1.83, and the maximum temperature achieved is 67oC, and the energy consumption seen from the total entalphy difference due to compression work is 81 kJ/kg. Without using the intercooler, the system’s COP is 1.72 and the maximum temperature achieved is 94.9oC and 86 kJ/kg of energy consumption. The energy required for the operational becomes more eficient and the heat released to the environment is much less, therefore the multistage cold storage with intercooler can be categorized as an eco-friendly technology.
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Mishra, R. S. "Thermodynamic Performance Evaluation of Multi-Evaporators Single Compressor and Single Expansion Valve and Liquid Vapour Heat Exchanger in Vapour Compression Refrigeration Systems using Thirteen Ecofriendly Refrigerants for Reducing Global Warming and Ozo". International Journal of Advance Research and Innovation 1, nr 3 (2013): 107–17. http://dx.doi.org/10.51976/ijari.131315.
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The methods for improving first law and second law efficiency have been considered in this paper by using liquid vapour heat exchanger is investigated in this paper. Detailed energy and exergy analysis of multi-evaporators at different temperatures with single compressor and single expansion valve using liquid vapour heat exchanger vapour compression refrigeration systems have been done in terms of performance parameter for R507a, R125, R134a, R290, R600, R600a, R1234ze, R1234yf, R410a, R407c, R707, R404a and R152a refrigerants. The numerical computations have been carried out for both systems. It was observed that first law and second law efficiency improved by 20% using liquid vapour heat exchanger in the vapour compression refrigeration systems. It was also observed that performance of both systems using R717 is higher but R600 and R152a nearly matching same values under the accuracy of 5% can be used in the above system .But difficulties using R152a, R600, R290 and R600a have flammable problems therefore safety measures are required using these refrigerants. Therefore R134a refrigerant is recommended for practical and commercial applications although it has slightly less thermal performance than R152a which is not widely used refrigerant for domestic and industrial applications
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Misra, R. K. "Thermodynamic Performance Evaluation of Multi-Evaporators single Compressor and single Expansion Valve and Liquid Vapour Heat Exchanger in Vapour Compression Refrigeration systems using Thirteen Eco-friendly Refrigerants for Reducing Global Warming and Oz". International Journal of Advance Research and Innovation 2, nr 2 (2014): 139–49. http://dx.doi.org/10.51976/ijari.221421.
Pełny tekst źródłaStreszczenie:
The methods for improving first law and second law efficiency have been considered in this paper by using liquid vapour heat exchanger is investigated in this paper. Detailed energy and exergy analysis of multi-evaporators at different temperatures with single compressor and single expansion valve using liquid vapour heat exchanger vapour compression refrigeration systems have been done in terms of performance parameter for R507a, R125, R134a, R290, R600, R600a, R1234ze, R1234yf, R410a, R407c, R707, R404a and R152a refrigerants. The numerical computations have been carried out for both systems. It was observed that first law and second law efficiency improved by 20% using liquid vapour heat exchanger in the vapour compression refrigeration systems. It was also observed that performance of both systems using R717 is higher but R600 and R152a nearly matching same values under the accuracy of 5% can be used in the above system .But difficulties using R152a, R600, R290 and R600a have flammable problems therefore safety measures are required using these refrigerants. Therefore R134a refrigerant is recommended for practical and commercial applications although it has slightly less thermal performance than R152a which is not widely used refrigerant for domestic and industrial applications
6
Sarabia, Daniel, María Cruz Ortiz i Luis Antonio Sarabia. "Integrated Design of a Supermarket Refrigeration System by Means of Experimental Design Adapted to Computational Problems". Algorithms 15, nr 11 (7.11.2022): 417. http://dx.doi.org/10.3390/a15110417.
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In this paper, an integrated design of a supermarket refrigeration system has been used to obtain a process with better operability. It is formulated as a multi-objective optimization problem where control performance is evaluated by six indices and the design variables are the number and discrete power of each compressor to be installed. The functional dependence between design and performance is unknown, and therefore the optimal configuration must be obtained through a computational experimentation. This work has a double objective: to adapt the surface response methodology (SRM) to optimize problems without experimental variability as are the computational ones and show the advantage of considering the integrated design. In the SRM framework, the problem is stated as a mixture design with constraints and a synergistic cubic model where a D-optimal design is applied to perform the experiments. Finally, the multi-objective problem is reduced to a single objective one by means of a desirability function. The optimal configuration of the power distribution of the three compressors, in percentage, is (50,20,20). This solution has an excellent behaviour with respect to the six indices proposed, with a significant reduction in time oscillations of controlled variables and power consumption compared with other possible power distributions.
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Samsi, Samsi, Ade Hermawan i Muhammad Ilham. "Product Refrigeration Load Analysis On Contact Plate Freezer On Compressor Performance At PT. Trimitra Makmur, Tarakan, North Kalimantan". Barakuda 45: Jurnal Ilmu Perikanan dan Kelautan 5, nr 1 (30.04.2023): 68–78. http://dx.doi.org/10.47685/barakuda45.v5i1.349.
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Contact plate freezer (CPF) is a cooling machine unit for freezing products which of course will maintain product freshness. In Order to runs smoothly, one thing that must be considered of the cooling system is the cooling load on the freezer contact plate. The cooling load is the amount of heat absorbed per unit time. The refrigeration cycle at PT. Trimitra Makmur uses a combined refrigeration cycle (multi-stage cycle), uses two cycles of vapor compression using two single-stage compressors. The two compressors used have the same power of 55.92 kW. The cooling load on the contact plate freezer consists of product heat load, water heat load, internal heat load, and transmission heat load. In The contact plate freezer, infiltration or heat load from the outside air are not counted because during production the contact plate freezer door is closed tightly so that the air exchange value is very small and can be neglected. In this study, the average total load on contact plate freezer 1 was 23.07079 kW, so that the average total load on the three contact plate freezers at PT. Trimitra Makmur is 69.21237 kW. The results of data collection and calculations show that the COP (Coefficient of Performance) value for the high-stage cycle is 4.33, so that the high-stage compressor power used is 1/4.33 of the cooling capacity of the contact plate freezer. Whereas in the booster cycle, a COP of 6.49 was obtained, so that the booster compressor power used was 1/6.49 of the cooling capacity of the contact plate freezer.
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Du, Yang, Nan Jiang, Yicen Zhang, Xu Wang, Pan Zhao, Jiangfeng Wang i Yiping Dai. "Multi-objective optimization of an innovative power-cooling integrated system based on gas turbine cycle with compressor inlet air precooling, Kalina cycle and ejector refrigeration cycle". Energy Conversion and Management 244 (wrzesień 2021): 114473. http://dx.doi.org/10.1016/j.enconman.2021.114473.
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Widell, K. N., i T. Eikevik. "Reducing power consumption in multi-compressor refrigeration systems". International Journal of Refrigeration 33, nr 1 (styczeń 2010): 88–94. http://dx.doi.org/10.1016/j.ijrefrig.2009.08.006.
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Bao, Huaiqian, Baokun Han, Yufeng Xu, Yuechao Liu i Guifang Liu. "The analysis of vibration response of air-cooled refrigerator excited by reciprocating compressor". E3S Web of Conferences 53 (2018): 02005. http://dx.doi.org/10.1051/e3sconf/20185302005.
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The features of large-capacity and multi temperature zones of air-cooled refrigerators are favored by consumers. However, the vibration of different components caused by the vibrations of different components in the operation process brings certain troubles to people's lives. In order to achieve better vibration and noise reduction of the refrigerator, the vibration characteristics of the air-cooled refrigerator are analyzed under the excitation of compressor, selects four detection points, and uses simulation methods to obtain the excitation of the compressor. In addition to the impact of the vibration source on the refrigerator, the assembly of refrigerator door is also an important factor of the refrigerator vibration. The experimental process has also found that the air-cooled system also has an impact on the vibration and noise generation of the refrigerator.
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Valencia, Guillermo E., Luis G. Obregon i Jorge Duarte. "Parametric study of cascade and multi-stage vapor compressor refrigeration systems using a Matlab guide". Contemporary Engineering Sciences 11, nr 26 (2018): 1261–68. http://dx.doi.org/10.12988/ces.2018.83115.
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Beckers, Jarl, Diederik Coppitters, Ward De Paepe, Francesco Contino, Joeri Van Mierlo i Björn Verrelst. "Multi-Fidelity Design Optimisation of a Solenoid-Driven Linear Compressor". Actuators 9, nr 2 (11.05.2020): 38. http://dx.doi.org/10.3390/act9020038.
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Improved management and impermeability of refrigerants is a leading solution to reverse global warming. Therefore, crank-driven reciprocating refrigerator compressors are gradually replaced by more efficient, oil-free and hermetic linear compressors. However, the design and operation of an electromagnetic actuator, fitted on the compression requirements of a reciprocating linear compressor, received limited attention. Current research mainly focuses on the optimisation of short stroke linear compressors, while long stroke compressors benefit from higher isentropic and volumetric efficiencies. Moreover, designing such a system focuses mainly on the trade-off between number of copper windings and the current required, due to the large computational cost of performing a full geometric design optimisation based on a Finite Element Method. Therefore, in this paper, a computationally-efficient, multi-objective design optimisation for six geometric design parameters has been applied on a solenoid driven linear compressor with a stroke of 44.2 mm. The proposed multi-fidelity optimisation approach takes advantage of established models for actuator optimisation in mechatronic applications, combined with analytical equations established for a solenoid actuator to increase the overall computational efficiency. This paper consists of the multi-fidelity optimisation algorithm, the analytic model and Finite Element Method of a solenoid and the optimised designs obtained for optimised power and copper volume, which dominates the actuator cost. The optimisation results illustrate a trade-off between minimising the peak power and minimising the volume of copper windings. Considering this trade-off, an intermediate design is highlighted, which requires 33.3% less power, at the expense of an increased copper volume by 5.3% as opposed to the design achieving the minimum copper volume. Despite that the effect of the number of windings on the input current remains a dominant design characteristic, adapting the geometric parameters reduces the actuator power requirements significantly as well. Finally, the multi-fidelity optimisation algorithm achieves a 74% reduction in computational cost as opposed to an entire Finite Element Method optimisation. Future work focuses on a similar optimisation approach for a permanent magnet linear actuator.
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Bartnik, Ryszard, Zbigniew Buryn, Anna Hnydiuk-Stefan, Waldemar Skomudek i Aleksandra Otawa. "Thermodynamic and Economic Analysis of Trigeneration System Comprising a Hierarchical Gas-Gas Engine for Production of Electricity, Heat and Cold". Energies 13, nr 4 (24.02.2020): 1006. http://dx.doi.org/10.3390/en13041006.
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This paper presents the results of analysis of energy and economic efficiency of the hierarchical gas-gas engine, with a note that a trigeneration system was analyzed, in which the production of electricity, heat and cold are combined. This solution significantly increases the energy efficiency of the gas and gas system compared to a system without cold production. The analysis includes a system comprising a compressor chiller which is driven by an electric motor in the system, as well as a system applying the mechanical work that is carried out via a rotating shaft of rotor-based machines, i.e., a gas turbine and a turboexpander. The comfort of the regulation of the refrigerating power rather promotes the use of a solution including an electric motor. Analysis contains also a schematic diagram of the system with a absorption chiller, which is driven by low-temperature enthalpy of exhaust gases extracted from a hierarchical gas-gas engine. Application of turboexpander with heat regeneration in the trigeneration system is also analyzed. Based on the multi-variant economic and thermodynamic calculations, the most favorable system variant was determined using, among others, the specific cost of cold production.
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Bolaji, Bukola Olalekan, Deborah Olufunke Bolaji i Semiu Taiwo Amosun. "Energy and cooling performance of carbon-dioxide and hydrofluoroolefins blends as eco-friendly substitutes for R410A in air-conditioning systems". Mechanical Engineering for Society and Industry 3, nr 1 (23.01.2023): 35–46. http://dx.doi.org/10.31603/mesi.8591.
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Air-conditioning and refrigeration systems are electrical appliances that use a huge amount of energy and contribute indirectly to global warming. Also, R410A which was initially developed as a substitute for ozone-depleting refrigerants in the air-conditioning systems has been phase-out due to its high global warming potential (GWP) and the resulting harmful effect on the climate. In addition to the issue of refrigerant high GWP, energy consumption is a significant issue. The energy efficiency of new refrigerants must then be considered in the search for alternative refrigerants to ensure that they do not lead to an increase in greenhouse gas generation at the power source. Therefore, this paper investigates the energy and cooling performance of four new multi-components and ecologically friendly refrigerant blends that contained carbon dioxide and hydrofluoroolefins in their compositions as substitutes for R410A in air-conditioning systems. Relevant thermodynamic equations and REFPROP software were employed for the computational analysis. The results indicated that the new blends (R445A, R455A, R470B and R470A) exhibited a desirable low compression ratio and high heat transfer for cooling applications. The blends also exhibited low compressor energy input and low specific cooling energy. R455A has an average coefficient of performance (COP) of 24.6% above that of the reference refrigerant (R410A). The cooling capacity per unit volume for R470B, R455A and R470A across a temperature range of 253 to 293 K are higher by 1.3, 6.0, and 12.6%, respectively than that of R410A. Generally, among all the four new substitute blends, the overall assessment revealed R455A as the best replacement for R410A in air-conditioning systems due to its superior performance in terms of its low compression ratio, compressor energy and specific cooling energy. R455A also has the highest COP and relatively high cooling capacity per unit volume.
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Moctezuma-Hernández, J. A., J. M. Belman-Flores, J. A. Soria-Alcaraz, A. Espinal-Jiménez i C. Rubio-Maya. "Modeling and Multi-Objective Optimization of a Miniature Refrigeration System". Journal of Thermal Science and Engineering Applications 14, nr 10 (11.04.2022). http://dx.doi.org/10.1115/1.4054070.
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Abstract In this study, the development of a physical model for a miniature refrigeration system is presented. The model is based on physical foundations and the incorporation of information provided in the manufacturers’ catalogs. The model is able to adequately predict the energy behavior of the refrigeration system, showing a maximum error of 10% in comparison with the experimental information found in the literature. Thus, the model is used to perform a multi-objective optimization by comparing two algorithms, nondominated storing genetic algorithm II and multi-objective particle swarm optimization algorithm. For this purpose, three scenarios are proposed whose objective functions involve parameters such as coefficient of performance, compressor discharge temperature, energy consumption, and refrigerant mass flowrate. The decision variables are the evaporation and condensation temperatures, the rotational speed of the compressor, and the degrees of subcooling and superheating. Thus, an overview of the optimal operating conditions that represent the best energy performance of the refrigeration system is provided.
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Alazazmeh, Ayman J., Esmail M. A. Mokheimer, Abdul Khaliq i Bilal A. Qureshi. "Performance Analysis of a Solar-Powered Multi-Effect Refrigeration System". Journal of Energy Resources Technology 141, nr 7 (9.01.2019). http://dx.doi.org/10.1115/1.4042240.
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The main objective of the current work is to investigate the thermodynamic performance of a novel solar powered multi-effect refrigeration system. The proposed cycle consists of a solar tower system with a heliostat field and central receiver (CR) that has molten salt as the heat transfer fluid, an absorption refrigeration cycle (ARC), an ejector refrigeration cycle (ERC), and a cascade refrigeration cycle (CRC). Energy and exergy analyses were carried out to measure the thermodynamic performance of the proposed cycle, using Dhahran weather data and operating conditions. The largest contribution to cycle irreversibility was found to be from the CR system (52.5%), followed by the heliostat field (25%). The first and second-law efficiencies improved due to the increase in the following parameters: ejector evaporator temperature, turbine inlet and exit pressures, and cascade evaporator temperature. Parametric analysis showed that the compressor delivery pressure, turbine inlet and exit pressures, hot molten salt outlet temperature, and ejector evaporator temperature significantly affect the refrigeration output.
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Xu, Yingjie, Songlin Huang, Jiafeng Wang, Mengjie Song, Jiaqi Yu i Xi Shen. "Energy and advanced exergy analyses of novel ejector-compressor partially-coupled refrigeration cycle for buildings with less solar energy". Journal of Renewable and Sustainable Energy, 31.07.2022. http://dx.doi.org/10.1063/5.0102885.
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Solar-driven ejection-compression refrigeration is helpful for building space cooling but is based on the precondition of solar heat being infinite and free. This is not valid in many cases, such as multi-storey buildings in metropolises with limited space. Even worse, in the carbon-neutral future, space surrounding buildings will be occupied by PV panels in priority. Therefore, a potential ejector-partially-coupled enhanced compression refrigeration cycle consuming less heat is presented. Models of the new cycle for a multistorey building are established. Then energy comparison and advanced exergy analysis is conducted. The analysis results firstly show that as the new cycle needs no auxiliary system. Powered by limited low-grade heat, its increased by 20.66% and TAC reduced by 7.8%, compared with the traditional ejector-compressor cycle. Advanced exergy analysis also finds that the order of improvement potential is compressor (4739.45W), evaporator (4329.85W), and condenser (2843.51W), according to the sum of avoidable exergy destruction. This is different from the results of conventional exergy analysis. The sensitivity analysis of the ejector components' efficiencies is investigated, which has seldom been reported for refrigeration system with ejector. Results reveal that once the efficiencies of ejector components reach a certain point (0.94), the performance no longer improves. Generally, this work provides a potential ejection-compression cycle, demonstrates system improvement direction through advanced exergy analysis, and reveals good understanding of the system.
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"Performance of Vapor Compression Refrigeration System using Nanoparticles – Based Mineral Oil Lubricant". International Journal of Recent Technology and Engineering 8, nr 3 (30.09.2019): 730–34. http://dx.doi.org/10.35940/ijrte.c3986.098319.
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In general, mineral oil and polyester oil are used as lubricants in a refrigeration system compressor. The present work focuses mainly on the mineral oil based lubricant based on MWCNT nanoparticles. The different characterization of the multi-wall carbon nanotube (MWCNT) was performed using different methods such as Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM), which will result in size, structure and morphology of the CNT nanoparticle. First prepare the Nano-lubricants by adding nanoparticles in mineral oil with different concentrations of 0.05, 0.075 and 0.1wt% with the help of an ultrasonicator which will give the homogeneous mixture of Nanolubricant. Nanoparticles mixed with mineral oil used in a refrigeration system work safely and normally. The experiment were conducted on refrigeration system for different concentration, namely 0.05, 0.075 and 0.1wt% which will mixed with mineral oil and without nanoparticles in mineral oil. The result shows that 0.1wt% Nanolubricant which will give higher improvement in heat transfer efficiency and increase in the Coefficient of Performance (COP) by 37%. And energy savings is 9.6%.
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dos Santos Vidal, Saulo Fernando, Jones Erni Schmitz, Ivan Carlos Franco, Ana Maria Frattini Fileti i Flavio Vasconcelos Da Silva. "Fuzzy Multivariable Control Strategy Applied to a Refrigeration System". Chemical Product and Process Modeling 12, nr 2 (30.07.2016). http://dx.doi.org/10.1515/cppm-2016-0033.
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Abstract The refrigeration process involves complex systems exhibiting nonlinearities and coupled behavior, so this paper aims to evaluate the comparative performance of a multivariable fuzzy logic-based control system and a classic multi loop PID. The process variables were the temperature of the secondary fluid (propylene glycol) outlet and the evaporating temperature. The manipulated variables were the compressor frequency speed and the pump frequency speed. Aspen Plus and Aspen Dynamics simulators were used to simulate the experimental prototype. The model was previously validated and linked with MATLAB software, where the controllers were implemented. Tuning of the fuzzy controller was performed through the membership functions and gains adjustments. The tuning of the multi loop PID controller was performed using the Ziegler-Nichols method and then a fine tuning was carried out. In order to fairly compare energy consumption and control effort, the tune of PID-based strategy was finished when similar values of Integral of Squared Error were achieved. Thus, very similar behavior for the process variables in both controllers. On the other hand, a great improvement in the control effort and energy saving was observed when the multivariable fuzzy controller was used in comparison to classic PID. The energy consumption was reduced by 25 % and the control effort by 96 % when the proposed strategy was used.
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Roy, Ranendra, Arup Jyoti Bhowal i Bijan Kumar Mandal. "Exergy and Cost Optimization of a Two-Stage Refrigeration System Using Refrigerant R32 and R410A". Journal of Thermal Science and Engineering Applications 12, nr 3 (28.02.2020). http://dx.doi.org/10.1115/1.4046253.
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Abstract An attempt has been made to investigate numerically a two-stage refrigeration system with flash intercooler of 50 kW cooling capacity using refrigerant R410A and its possible alternative R32. Development of the simulation model for the analysis of the system has been carried out in engineering equation solver considering the energetic, exergetic, economic, and environmental aspects. Evaporator and condenser temperatures have been varied from −50 °C to −25 °C and 40 °C to 55 °C, respectively, to carry out the simulation work. Co-efficient of performance (COP), exergetic efficiency, and plant cost rate are the three performance parameters computed in this present work. Results show that the performances of the system using R32 are comparable with those of the system using R410A. It is also observed that R32 shows slightly better thermo-economic performances at higher condenser temperature. Multi-objective optimization has also been carried out using the toolbox available for optimization in matlab to obtain the optimum performance and optimum operating conditions for both the refrigerants. Optimization results also show better thermo-economic performances of R32 over R410A though compressor discharge temperature is higher in case of R32.
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Khan, Mehtab, Adnan Daud Khan, Muhammad Jawad, Zahoor Ahmad, Naveed Ur Rehman i Muhammad Israr. "Design and analysis of modular moving magnet linear oscillating actuator for compressor in refrigeration system". World Journal of Engineering, 8.07.2022. http://dx.doi.org/10.1108/wje-12-2021-0671.
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Purpose This paper aims to investigates a novel design of a modular moving magnet linear oscillating actuator (MMM-LOA) with the capability of coupling modules, based on their application and space requirements. Design/methodology/approach Proposed design comprised of modules, and modules are separated by using nonmagnetic materials. Movable part of the proposed design of LOA is composed of permanent magnets (PMs) having axial magnetization direction and tubular structure. Stator of the proposed design is composed of one coil individually in a module. Dimensions of the design parameters are optimized through parametric analysis using COMSOL Multi Physics software. This design is analyzed up to three modules and their response in term of electromagnetic (EM) force and stroke are presented. Influence of adding modules is analyzed for both directions of direct current (DC) and alternating input loadings. Findings Proposed LOA shows linear increase in magnitude of EM force by adding modules. Motor constant of the investigated LOA is 264 N/A and EM force per PM mass is 452.389 N/kg, that shows significant improvement. Moreover, proposed LOA operates in feasible region of stroke for compressor application. Furthermore, this design uses axially magnetized PMs which are low cost and available in compact tubular structure. Originality/value Proposed LOA shows the influence of adding modules and its effect in term of EM force is analyzed for DC and alternating current (AC). Moreover, overall performance and structural topology is compared with state-of-the-art designs of LOA. Improvement with regard of motor constant and EM force per PM mass shows originality and scope of this paper.
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Ma, Yanan, i Peng Hu. "Thermo-economic comparative study and Multi-objective optimization of supercritical CO2-based mixtures Brayton cycle combined with absorption refrigeration cycle". Journal of Thermal Science and Engineering Applications, 27.04.2023, 1–14. http://dx.doi.org/10.1115/1.4062435.
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Abstract In this paper, a novel system based on the combination of a supercritical recompression Brayton cycle (SRBC) and LiBr-H2O absorption refrigeration cycle (ARC) is proposed, in which ARC utilizes the waste heat of SRBC for cooling and further reduces main compressor inlet temperature. The potential of using xenon and krypton as additives for supercritical CO2 Brayton cycle is explored via comparative analysis. The results show that CO2/Krypton is more suitable to be working fluid of combined system because of its higher thermal efficiency and lower costs. The effects of the operating parameters and mass fraction of krypton on the thermo-economic performance of combined system are discussed. Multi-objective optimization is applied to simultaneously optimize the thermal efficiency and total product unit cost of the system. Compared with stand-alone cycle, combined system can improve the cycle efficiency over a wide temperature range. The exergy efficiency of SRBC/ARC using CO2/Krypton (0.64/0.36) increased from 0.638 to 0.688, from 0.653 to 0.665, and from 0.586 to 0.646 at ambient temperature T0 = 10, 25, 35°C, respectively, increasing by 7.84%, 1.84% and 10.24% compared with SCO2RBC. The combined system will achieve its full potential when the critical temperature of the working fluid is close to the ambient temperature.
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"Development of Multi use Refrigeration System". International Journal of Recent Technology and Engineering 8, nr 2 (30.07.2019): 2387–90. http://dx.doi.org/10.35940/ijrte.a9251.078219.
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Conservation of energy is the important factor from global point of view. Waste heat recovery has become significantly necessary and instant effort should be made to conserve this waste energy. Presently the refrigerator system rejects a lot of heat through condenser. This heat can be used for a variety of useful purposes. A multiuse refrigeration setup has been developed in which, both heating and cooling will be done simultaneously with the help of single vapour compression refrigeration cycle. It has a waste heat recovery system from the compressor for heating effect. Here without disturbing refrigeration cycle, the waste heat energy is used for useful work. The study has shown that such a system is technically feasible and economically viable. This concept has a scope of applications in variety of products such as air conditioners, freezers, water coolers and small scale refrigeration plants. This project leads to hybrid heating and cooling application with same vapour compression refrigeration system
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Borges, Gabriel, Diego Salvaro, Roberto Binder, Cristiano Binder, Aloisio N. Klein i Jose D. B. de Mello. "In situ Tribo-Fluorination for Oil-Less Hermetic Compressor Applications". Frontiers in Mechanical Engineering 7 (17.03.2021). http://dx.doi.org/10.3389/fmech.2021.652001.
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In the present work, we overview the multidisciplinary development of a regular, lubricated, hermetic compressor which works in an on-off cycle, circular motion, single-speed, many tribological contacts, into an innovative, linear motion, variable displacement, single tribological contact, oil-less hermetic compressor presenting high versatility in terms of refrigerator design, sustainability and improved efficiency. The original approach encompassed the development of new surface engineering procedures applying purpose-oriented phases to soft substrates. Particular emphasis is given to the in situ fluorination of the tribolayer formed in the piston-cylinder tribopair. Although chlorinated halocarbons (CFC) are efficient refrigerants from a thermodynamic point of view, they do have serious environmental implications that have forced the refrigeration industry to switch to more environmentally friendly hydrofluorocarbon (HFC) based refrigerants. The first and most successful alternative to the CFCs was tetrafluorocarbon, particularly tetrafluoroethane (CF3CH2F), aka R134a refrigerant. The current trend to downsizing mechanical systems, smaller clearances, and increased speeds leading to greater energy efficiencies associated with miscibility issues imposing the use of costly, fully synthetic lubricants with the R134a refrigerant gas led to the introduction of a new hermetic compressor design, the Wisemotion®, the first, and until now, unique, oil-free hermetic compressor on the world market. In this context different types of multi-layers, their thickness, substrate material, processing routes, etc., have been studied and optimized. Si-rich hydrogenated DLC (a:C-H) presented enhanced tribological properties when tested under fluorine-rich atmospheres, and semi-industrial scale tests have been carried out to understand this point further. A homemade tribological emulator was developed allowing close-to-real tribopair, atmosphere, and imposed mechanical conditions used in an oil-free commercial hermetic compressor. The tests were carried under different stroke frequencies (5, 20, and 40 Hz) and atmospheres (R134a, ambient air, and argon). Results showed a strong influence of both atmosphere and stroke frequencies. The friction coefficients were significantly lower (~3.8X) for the refrigerant gas atmosphere, attributed to the fluorine and highly disordered graphitic structures rich tribolayers. Under the high frequency (40 Hz), the energy input seems to be a deterrent to the formation of stable tribolayers, and the DLC coating shatters on the first few sliding meters.
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Alihosseini, Nader, Gholamreza Salehi i Arash Mirabdolah Lavasani. "Exergy and exergoeconomic analyses of serial and bypass two-stage compression on the household refrigerator-freezer and replacement of R436A refrigerant". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 14.07.2021, 095765092110324. http://dx.doi.org/10.1177/09576509211032495.
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In this research, the performance of serial two-stage compression (STC) cycle and bypass two-stage compression (BTC) cycle on the household refrigerator-freezers is tested in the laboratory. Then, based on the results of the experiments, exergy, exergoeconomic analyses, and cycle optimization are carried out. Considering that replacing refrigerants in household refrigerator-freezers is one of the approaches to increase the performance and environmental impact of these systems, R436A refrigerant (46% Isobutene and 54% Propane mixture) is used and analyzed to replace previous refrigerants. Finally, the multi-objective optimization of the mentioned cycles is performed with both refrigerants. For analyses, two models of refrigerator-freezers with different cycles are used (STC cycle with R134a refrigerant and BTC cycle with R-600a refrigerant). In both models, two evaporators for refrigerator-freezer compartments are used. International standards (IEC 62552) are used to test refrigerator-freezers. MATLAB and REFPROP 9.1 software are used to model the systems. According to the results of the analyses, the STC cycle with R436A refrigerant has more total exergy destruction rate (0.727 kW) compared to R134a refrigerant. In the BTC cycle, in which the fresh food compartment (FFC) and freezer compartment (FZC) operate, the total exergy destruction rate with R-600a refrigerant (0.422 kW) is less than with R436A refrigerant. In the case of the BTC cycle in which only the FZC operates, the total exergy destruction rate with R-600a refrigerant (0.455 kW) is less than with R436A refrigerant. The most exergoeconomic factor among cycle equipment is related to the compressor (about 98%). The highest COP value between cycles is related to the STC cycle with R134a refrigerant.