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1
Трушляков, Євген Іванович, Андрій Миколайович Радченко, Сергій Анатолійович Кантор, Веніамін Сергійович Ткаченко, Сергій Георгійович Фордуй та Ян Зонмін. "ВИЗНАЧЕННЯ ПРОЕКТНОЇ ХОЛОДОПРОДУКТИВНОСТІ СИСТЕМИ КОНДИЦІЮВАННЯ ПОВІТРЯ В КОНКРЕТНИХ КЛІМАТИЧНИХ УМОВАХ І РІЗНИМИ МЕТОДАМИ". Aerospace technic and technology, № 6 (24 грудня 2019): 15–19. http://dx.doi.org/10.32620/aktt.2019.6.03.
Повний текст джерелаАнотація:
The cold output for the heat-moisture treatment of ambient air in air conditioning systems depends on its parameters (temperature and relative humidity), which vary significantly during operation. To determine the installed (design) cooling capacity of air conditioning system chillers, it is proposed to use a reduction in fuel consumption of a power plant or cooling capacity generation following its current conditioning spending over a certain period, since both of these indicators characterize the efficiency of using the installed cooling capacities of the air conditioning system. To extend the results of the investigation to a wide range of air conditioning units, two methods were used to determine the design cooling capacity (refrigerating capacity): by the maximum annual value and by the maximum growth rate of the efficiency indicator. The first method allows choosing the design cooling capacity, which provides a maximum annual reduction in the specific fuel consumption due to air cooling or maximum cooling capacity generation, which is necessary for air cooling following current climatic conditions. The second method allows determining the minimum design (installed) cooling capacity of chillers, which provides the maximum rate of reduction in fuel consumption by the power plant and the increment in the annual cooling capacity generation following the installed cooling capacity of chillers. The efficiency of air conditioning systems was analyzed for different climatic conditions: a temperate climate using the example of Voznesensk city (Ukraine) and the subtropical climate of Nanjing city (China). It is shown that the design cooling capacity values calculated by both indicators of its use efficiency are the same for the same climatic conditions. Wherein, if to determine the design cooling capacity by both methods - by the maximum annual value and the maximum rate of growth of the indicator, its values turned out to be quite close for tropical climatic conditions and somewhat different for a temperate climate.
2
Kula, Sinan. "Design Studies of Two Stage Cooling Loop for New Generation Vehicles." Academic Perspective Procedia 3, no. 1 (October 25, 2020): 550–59. http://dx.doi.org/10.33793/acperpro.03.01.104.
Повний текст джерелаАнотація:
In this article, the design and integration of an intelligent refrigeration system that increases air conditioning and engine efficiency, reduces fuel consumption and emission levels in vehicles manufactured today will be examined. This design will include a two-stage cooling system. Two-stage cooling unit consist; high temperature radiator and low temperature radiator. The engine coolant will be cooled in the high temperature radiator. In the low temperature radiator, coolant of water cooled air charger and air conditioning condenser will be cooled. It is aimed to increase the engine efficiency by cooling more efficiently, thanks to the heat carrying capacity of the water which is high compared to air. With this project, it is aimed to cool the heated air after the turbocharging and air conditioning gas in the vehicle with water instead of air.
3
Volkova, Anna, Aleksandr Hlebnikov, Aleksandr Ledvanov, Tanel Kirs, Urmas Raudsepp, and Eduard Latõšov. "District Cooling Network Planning. A Case Study of Tallinn." International Journal of Sustainable Energy Planning and Management 34 (May 25, 2022): 63–78. http://dx.doi.org/10.54337/ijsepm.7011.
Повний текст джерелаАнотація:
The planning procedure for district cooling as an urban system was presented and carried out using the example of the Tallinn city centre. The following steps were described in detail: cooling demand determination, cooling generation planning and cooling transition analysis. Based on the three proposed methods (average specific cooling load, satellite imagery analysis of a specific building, counting the number of fans in dry coolers and the combination method), the cooling capacity of the evaluated district was estimated at 63.2 MW. In terms of cooling generation, the analysis shows that seawater for free cooling can cover up to 55% of the annual cooling consumption. Electric chillers and absorption chillers that use surplus heat can cover the rest of the district cooling demand. The district cooling network was designed for three scenarios: with one generating unit, with two generating units and a looped network. Despite the fact that the looped network is the most expensive option, this type of solution is considered feasible as it will make it easier to connect new consumers.
4
Zhang, Wenjie, Jiajun Zhang, Fengcheng Huang, Yuqiang Zhao, and Yongheng Zhong. "Study of the Application Characteristics of Photovoltaic-Thermoelectric Radiant Windows." Energies 14, no. 20 (October 14, 2021): 6645. http://dx.doi.org/10.3390/en14206645.
Повний текст джерелаАнотація:
Through experiments and numerical simulation, this paper studies the related performance of a photovoltaic thermoelectric radiation cooling window structure, verifies the accuracy of the established solar thermoelectric radiation window calculation model, and analyzes the cooling performance of different parameters of thermoelectric sheet, radiation plate, and photovoltaic panel. On the basis of considering the relationship between the power generation and power consumption of the structure, the numerical calculation results show that the solar thermoelectric radiation window with non-transparent photovoltaic module (NTPV) has a total cooling capacity of 50.2 kWh, power consumption of 71.8 kWh, and power generation of 83.9 kWh from June to August. The solar thermoelectric radiation window with translucent photovoltaic module (STPV) has a total cooling capacity of 50.7 kWh, power consumption of 71.7 kWh, and power generation of 45.4 kWh from June to August. If the operation time of the thermoelectric module is limited, when the daily operation time of TEM is less than 8 h, the power generation of STPV can meet the power consumption demand of the thermoelectric radiation window from June to August.
5
Yu, Ming Guo, Shu Hui Wang, Jia Qiang E, and Xiao Feng Hu. "Heat Transfer Capacity of Composite Cooling System for Automobile Lithium-Ion Battery with Heat Pipe and Phase Change Materials." Advanced Materials Research 941-944 (June 2014): 2469–73. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.2469.
Повний текст джерелаАнотація:
Combining high thermal conductivity and high latent heat of phase change Materials (PCM) with heat pipe that has strong ability of heat transfer. A three-dimensional transient heat-transfer model was set up to simulate the temperature distribution in the lithium-ion battery under different conditions of heat generation rate and different ambient temperature. The study revealed that composite cooling system keep the battery temperature below 40.2°C on average working condition, the highest temperature was not exceed 48.7°C even under stressful conditions. However, use PCM without heat pipe as cooling system, the temperature was 2~6°C higher than composite cooling system at the same condition. The composite cooling system was superior to PCM cooling system, especially in high heat generation rate and high ambient temperature.
6
Kakaras, E., A. Doukelis, A. Prelipceanu, and S. Karellas. "Inlet Air Cooling Methods for Gas Turbine Based Power Plants." Journal of Engineering for Gas Turbines and Power 128, no. 2 (September 23, 2005): 312–17. http://dx.doi.org/10.1115/1.2131888.
Повний текст джерелаАнотація:
Background: Power generation from gas turbines is penalized by a substantial power output loss with increased ambient temperature. By cooling down the gas turbine intake air, the power output penalty can be mitigated. Method of Approach: The purpose of this paper is to review the state of the art in applications for reducing the gas turbine intake air temperature and examine the merits from integration of the different air-cooling methods in gas-turbine-based power plants. Three different intake air-cooling, methods (evaporative cooling, refrigeration cooling, and evaporative cooling of precompressed air) have been applied in two combined cycle power plants and two gas turbine plants. The calculations were performed on a yearly basis of operation, taking into account the time-varying climatic conditions. The economics from integration of the different cooling systems were calculated and compared. Results: The results have demonstrated that the highest incremental electricity generation is realized by absorption intake air-cooling. In terms of the economic performance of the investment, the evaporative cooler has the lowest total cost of incremental electricity generation and the lowest payback period (PB). Concerning the cooling method of pre-compressed air, the results show a significant gain in capacity, but the total cost of incremental electricity generation in this case is the highest. Conclusions: Because of the much higher capacity gain by an absorption chiller system, the evaporative cooler and the absorption chiller system may both be selected for boosting the performance of gas-turbine-based power plants, depending on the prevailing requirements of the plant operator.
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Gwak, Geonhui, Minwoo Kim, Dohwan Kim, Muhammad Faizan, Kyeongmin Oh, Jaeseung Lee, Jaeyoo Choi, Nammin Lee, Kisung Lim, and Hyunchul Ju. "Performance and Efficiency Analysis of an HT-PEMFC System with an Absorption Chiller for Tri-Generation Applications." Energies 12, no. 5 (March 8, 2019): 905. http://dx.doi.org/10.3390/en12050905.
Повний текст джерелаАнотація:
An absorption chiller model for tri-generation (combined cooling, heating, and power) is developed and incorporated with the high temperature- (HT-) proton exchange membrane fuel cell (PEMFC) system model that was developed in our previous study. We employ a commercially available flow simulator, Aspen HYSYS, for solving the energy and mass balances of various system components, including an HT-PEMFC stack that is based on a phosphoric acid-doped PBI membrane, natural gas-fueled reformer, LiBr-H2O absorption chiller, balance of plant (BOP) components, and heat exchangers. Since the system’s operating strategy for tri-generation must be changed, depending on cooling or heating loads, a major focus of this study is to analyze system performance and efficiency under different requirements of electricity generation, cooling, and heating conditions. The system simulation results revealed that high-current fuel-cell operation is essential in raising the cooling capacity, but the overall system efficiency is slightly reduced as a result. Using a lower fuel-air ratio for the burner in the reforming module is one alternative that can minimize the reduction in the overall system efficiency under high-current fuel-cell operation and large cooling-capacity modes.
8
Khosala, Yudha. "Thermal Calculation for Water Cooling Tower To Cool Compressor ATLAS COPCO GA 250 FF." ACMIT Proceedings 3, no. 1 (March 18, 2019): 193–200. http://dx.doi.org/10.33555/acmit.v3i1.44.
Повний текст джерелаАнотація:
The aim of this paper is to choose the correct capacity of Thermal Calculation for Water Cooling Tower to Cool Compressor ATLAS COPCO GA 250 FF since a cooling tower is considered as an essential component for a compressor in an oil and gas pipe manufacture plant. Cooling tower is an equipment device commonly used to dissipate heat from air conditioning, water-cooled refrigeration, power generation units, and industrial process. In this paper, we use a induced draft counter flow tower for the design of cooling tower which based on Merkel’s method. The tower characteristic is determined by Merkel’s method. A simple algebraic formula is used to calculate the optimum water and air flow rate. This paper calculate the cooling tower characteristic, air flow required, efficiency, effectiveness, and cooling capacity of cooling tower need to cool the compressor compare with the availability cooling tower product in the market. In this paper, we will design based on calculation thermal capacity which lead to decentralizing the cooling tower to reach better energy efficiency of the plant.
9
Трушляков, Євген Іванович, Андрій Миколайович Радченко, Микола Іванович Радченко, Сергій Анатолійович Кантор та Веніамін Сергійович Ткаченко. "ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ КОНДИЦІЮВАННЯ ЗОВНІШНЬОГО ПОВІТРЯ СИСТЕМИ КОМБІНОВАНОГО ТИПУ". Aerospace technic and technology, № 4 (31 серпня 2019): 9–14. http://dx.doi.org/10.32620/aktt.2019.4.02.
Повний текст джерелаАнотація:
One of the most attractive reserves of enhancing the energetic efficiency of air conditioning systems is to provide the operation of refrigeration compressors in nominal or close to nominal modes by choosing rational design cooling loads (cooling capacities) and their distribution according to a cooling load behaviour within the overall design (installed) cooling load band to match current changeable climatic conditions and provide close to maximum annual cooling capacity generation according to cooling duties. The direction of increasing the efficiency of outdoor air conditioning in combined central-local type systems by rationally distributing the heat load - cooling capacity of the central air conditioner into zones of variable heat load in accordance with current climatic conditions and its relatively stable value, i.e. cooling capacity required for further air cooling at the entrance to the indoor recirculation air conditioning system is justified. By comparing the values of the excessive production of cold and its deficit within every 3 days for a rational design heat load of the air conditioning system (cooling capacity of the installed refrigeration machine), which provides close to maximum annual production of cold, and the corresponding values of the excess and deficit of cooling capacity in accordance with current climatic conditions during July substantiated the feasibility of accumulating the excess of cooling capacity of a central air conditioner at low current loads and its use for covering cooling deficit at elevated heat loads through pre-cooling the outdoor air. It is developed a scheme of a combined central-local air conditioning system, which includes the subsystems for the outdoor air conditioning in a central air conditioner and the local indoor recirculated air conditioning.
10
Du, Jiuyu, Yizhao Sun, Yingxuan Huang, and Xiaogang Wu. "Analysis of Influencing Factors of Thermal Management System for LiFePO4 Lithium Battery under High Power Charging." World Electric Vehicle Journal 11, no. 2 (June 4, 2020): 44. http://dx.doi.org/10.3390/wevj11020044.
Повний текст джерелаАнотація:
During the high-power charging process, the heat generated by the power battery is significantly increased, resulting in a significant temperature rise, which will bring safety hazards and worsens capacity degradation. In this study, we focus on the energy storage system composed of LiFePO4 pouch battery cells whose capacity is 30Ah. The coupling calculation between the one-dimensional electro-chemical model and the 3D heat generation model is realized. The accuracy of the model is verified by charging the battery at different rates. The results show that the inlet flow rate and the cooling channel size within a certain range has a great influence on the cooling effect of the battery pack during high power charging process. Comparing the temperature distribution of the battery pack under different charging rates, the electrochemical-heating coupling model established in this study can truly reflect the heat generation of the battery. Through the calculation of the heat generation of the battery pack, the boundary conditions of the cooling system design can be found, which provides a basis for the optimal design of the conditional cooling system for battery high-power charging.
11
Yoon, Jung In, Ho Saeng Lee, Chang Hyo Son, Sung Hoon Seol, Kwang Seok Lee, Hyeon Ju Kim, and Jung Hyun Moon. "Effect of Entrainment Ratio and Subcooling Degree on Dual System of Cooling-Thermal Energy Conversion Applying Ejector." Defect and Diffusion Forum 379 (November 2017): 140–48. http://dx.doi.org/10.4028/www.scientific.net/ddf.379.140.
Повний текст джерелаАнотація:
This study proposes a system called 'dual system of cooling-thermal energy conversion applying ejector', which practically applies an ejector to an ocean thermal energy conversion (OTEC) system. The proposed system presents higher system efficiency, owing to the application of an ejector, and reduced initial and operating costs. The main results, obtained from simulation analysis, are as follows: the cooling capacity tended to decrease as the entrainment ratio increased, and the system using R134a generally presented the highest cooling capacity and COP. In terms of generation system, the highest turbine gross power was obtained when the R134a working fluid was applied. The efficiency of the system decreased as the entrainment ratio increased. Finally, the application of the ejector enhanced the efficiency of the generation system, using R134a, by approximately 50%, from 4.73% to 7.10% at the entrainment ratio of 0.1.
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Ismagilov, Flur, Irek Khayrullin, Vyacheslav Vavilov, Ruslan Karimov, and Anton Gorbunov. "High-Performance Generator for a New Generation of Aircrafts." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 5 (October 1, 2017): 2338. http://dx.doi.org/10.11591/ijece.v7i5.pp2338-2348.
Повний текст джерелаАнотація:
The article describes multidisciplinary design process of high-performance electric generator for advanced aircrafts by analytical methods and computer modeling techniques (electromagnetic, thermal and mechanical calculations). New technical solutions used in its development are described. The main ideas are revealed of the method of EG voltage stabilization we used. To improve the heat dissipation efficiency, we have developed a new cooling system, and provide its study and description in this paper. The advantages of this cooling system include the fact that EG is made with dry, uncooled rotor. This allowed eliminating additional pumps, and significantly reducing the size of CSD. According to the results of our study, we created an experimental full capacity layout, and its studies are also provided in this paper.
13
Kishalov, Aleksandr E., and Almir A. Zinnatullin. "Study of the soil temperature effect on the operation of a low-capacity power plant’s condenser." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 6, no. 1 (2020): 118–34. http://dx.doi.org/10.21684/2411-7978-2020-6-1-118-134.
Повний текст джерелаАнотація:
Every year, the share of decentralized energy generation in Russia is increasing. The following factors contribute to the development of this scenario: increased wear of the country’s energy system equipment, energy shortages, and lack of centralized energy supply in a number of regions and constantly rising tariffs. One of the methods of decentralized energy generation is the use of low-capacity power plants based on the Rankine cycle with an organic working fluid. The operation of such plants requires cooling and condensation of the working fluid by transferring its heat to the environment. This study discusses the design of such a power plant and the heat removal system to a cold source. is the authors consider the design of a condenser which is a horizontal pipeline placed in the ground. Seasonal fluctuations of the soil temperatures affect the operation of the condenser. Thereby, to ensure the stable operation of the power plant, it is necessary to quantitatively assess the effect of the annual dynamics of the soil temperature state on cooling and condensation of the coolant. The study of the temperature fields of the soil, pipeline and working fluid, as well as the lengths required for cooling and condensation of the working fluid, was carried out in the ANSYS CFX software package for numerical hydrodynamic modeling. A homogeneous flow model was chosen to simulate the momentum and condensation of a vapor-liquid medium. Also, the calculations were conducted in a one-dimensional formulation using an engineering method. A methodology for modeling complex processes of heat transfer to the soil using numerical modeling has been developed and verified. 12 calculations were made; the distributions of the steam dryness and temperature in the simulated region depending on the time of the year were obtained. The functions of the total length of the pipeline, cooling and condensation lengths on the soil temperature are analyzed. It has been established that the harmonic change in the temperature of the soil set as the initial condition determines a similar change in the lengths required for cooling and condensation of the working fluid. Using this technique, it is possible to calculate pipelines of more complex shapes. The obtained temperature distributions in cross sections allow to establish the optimal distance between the axes of the pipes when designing a condenser in the form of a bundle of horizontal pipes or a bent pipeline.
14
Michaelides, Efstathios E. "Thermal Storage for District Cooling—Implications for Renewable Energy Transition." Energies 14, no. 21 (November 4, 2021): 7317. http://dx.doi.org/10.3390/en14217317.
Повний текст джерелаАнотація:
The utilization of air conditioning in public and private buildings is continuously increasing globally and is one of the major factors fueling the growth of the global electricity demand. The higher utilization of renewable energy sources and the transition of the electricity-generating industry to renewable energy sources requires significant energy storage in order to avoid supply–demand mismatches. This storage-regeneration process entails dissipation, which leads to higher energy generation loads. Both the energy generation and the required storage may be reduced using thermal energy storage to provide domestic comfort in buildings. The development and utilization of thermal storage, achieved by chilled water, in a community of two thousand buildings located in the North Texas region are proven to have profound and beneficial effects on the necessary infrastructure to make this community independent of the grid and self-sufficient with renewable energy. The simulations show that both the necessary photovoltaics rating and the capacity of the electric energy storage system are significantly reduced when thermal storage with a chilled water system is used during the air conditioning season.
15
Khan, Banti, Ashita Goyal, and Ashutosh Kumar Chobey. "IMPROVING THERMAL WITHSTANDING CAPACITY OF THREE PHASE INDUCTION MOTOR USING NWCC METHOD." International Journal of Research -GRANTHAALAYAH 2, no. 3 (December 31, 2014): 40–51. http://dx.doi.org/10.29121/granthaalayah.v2.i3.2014.3058.
Повний текст джерелаАнотація:
Three phase induction motors are widely used in industries due to their various technical as well as economical advantages. About 60% of industrial electricity is consumed by these motors, but the heat generation inside the motor due to various losses is a critical factor which degrades the dielectric properties of insulation and shortening the lifespan of motor. This paper presents the capillary based water cooling method of three phase squirrel cage induction motor. In this method, a jacket of capillaries made of jute and cotton is used as a outer cover for the motor casing. A small air gap passage is provided in between motor casing and inner surface of jacket. Natural Water Cooling Capillaries (NWCC) method is used to lower down the surrounding temperature of motor which reduces heating limitations of motor. For this purpose we select a 1.1kW three phase, 50Hz squirrel cage induction motor. Heat run test is performed on this motor to determine the total loss of energy dissipated as heat on three phase squirrel cage induction motor with and without adopting capillary based water cooling method. Comparison is done on the basis of experimental result which shows that the temperature withstanding capacity of induction motor will increase by 15.5 % after adopting capillary based water cooling method. This is an economical method and no external energy is required for cooling purpose.
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Chen, Ziyu, Kexin Hu, Yinbo Mao, Xinrong Su, and Xin Yuan. "Interaction Mechanism and Loss Analysis of Mixing between Film Cooling Jet and Passage Vortex." Entropy 24, no. 1 (December 22, 2021): 15. http://dx.doi.org/10.3390/e24010015.
Повний текст джерелаАнотація:
The interaction between the film-cooling jet and vortex structures in the turbine passage plays an important role in the endwall cooling design. In this study, a simplified topology of a blunt body with a half-cylinder is introduced to simulate the formation of the leading-edge horseshoe vortex, where similarity compared with that in the turbine cascade is satisfied. The shaped cooling hole is located in the passage. With this specially designed model, the interaction mechanism between the cooling jet and the passage vortex can therefore be separated from the crossflow and the pressure gradient, which also affect the cooling jet. The loss-analysis method based on the entropy generation rate is introduced, which locates where losses of the cooling capacity occur and reveals the underlying mechanism during the mixing process. Results show that the cooling performance is sensitive to the hole location. The injection/passage vortex interaction can help enhance the coolant lateral coverage, thus improving the cooling performance when the hole is located at the downwash region. The coolant is able to conserve its structure in that, during the interaction process, the kidney vortex with the positive rotating direction can survive with the negative-rotating passage vortex, and the mixture is suppressed. However, the larger-scale passage vortex eats the negative leg of the kidney vortices when the cooling hole is at the upwash region. As a result, the coolant is fully entrained into the main flow. Changes in the blowing ratio alter the overall cooling effectiveness but have a negligible effect on the interaction mechanism. The optimum blowing ratio increases when the hole is located at the downwash region.
17
Gomri, Rabah, and Billel Mebarki. "Study and Analysis by Numerical Simulation of a Solar Continuous Adsorption Chiller." Applied Mechanics and Materials 773-774 (July 2015): 605–9. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.605.
Повний текст джерелаАнотація:
Environment and energy problems over the world have motivated researchers to develop energy systems more sustainable, having as one of the possible alternative the use of solar energy as source for cooling systems. Adsorption refrigeration systems are regarded as environmentally friendly alternatives to conventional vapour compression refrigeration systems, since they can use refrigerants that do not contribute to ozone layer depletion and global warming. In this paper a performance comparison between a solar continuous adsorption cooling system without mass recovery process and solar continuous adsorption cooling system with mass recovery process is carried out. Silica-Gel as adsorbent and water as refrigerant are selected. The results show that the adsorption refrigeration machine driven by solar energy can operate effectively during four months and is able to produce cold continuously along the 24 hours of the day. The importance of the mass recovery is proved in this study by increasing the coefficient of performance and the cooling capacity produced. For the same cooling capacity produced, the required number of solar collectors with mass recovery system is lower than the required number of solar collectors in the case of the refrigeration unit without mass recovery. For the same cooling capacity the system with mass recovery process allowed lower generation temperature.
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Gong, Xue Min, Jiu Lin Yang, and Chen Wang. "Optimization of a Sintering Waste Heat Power Unit." Advanced Materials Research 1008-1009 (August 2014): 897–900. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.897.
Повний текст джерелаАнотація:
An optimization was performed for a sintering waste heat power unit with all data obtained in the site and under the unit normal operating conditions. The physical and mathematical model for the process of cooling and generation is established, which makes the net power generation as an objective function of the cooling machine imported ventilation, the thickness of sinter and the main steam pressure. Optimizing for single parameter, we found that each parameter had an optimal value for the system. In order to further optimize the system's operating parameters, genetic algorithm was used to make the combinatorial optimization of the three parameters. Optimization results show that power generation capacity per ton is increased by13.10%, and net power generation is increased by 16.17%. The optimization is instructive to the operation of sintering waste heat power unit.
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López-Leyva, Josué Aarón, Carolina Barrera-Silva, Luisa Fernanda Sarmiento-Leyva, and María Fernanda González-Romero. "Active Buildings Based on Passivhaus Standard to Reduce the Energy Deficit of Regional Electric Network: Proposal Analysis." Electronics 10, no. 19 (September 28, 2021): 2361. http://dx.doi.org/10.3390/electronics10192361.
Повний текст джерелаАнотація:
This manuscript presents the analysis of a real distributed generation network considering the integration of Active Buildings that meet the Passivhaus standard criteria at the Premium level, as a base case model. The novelty aspect presented in this paper is the interconnection of Active Buildings based on the Passivhaus standard at the Premium level with the National Electricity System (particularly, in Mexico’s North Baja California region) to mitigate the energy deficit. The objective of the proposal grid is to reduce the energy deficit (≈600 MW) due to the high energy demand in the region and the reduced energy generation through conventional and renewable energy sources. In a particular way, the energy rehabilitation of some buildings was analyzed with the aim of reducing the energy demand of each one and then adding energy generation through renewable sources. As a result, all Passivhaus standard criteria (i.e., heating and cooling demands, heating and cooling loads, among others) were met. Regarding the Active Buildings performance in each distributed generation circuit, an overall installed power capacity of ≈2.3 MW was obtained, which corresponds to ≈19.1% of the maximum capacity, and ≈34.30% of the recommended integration capacity. In addition, adequate results were obtained related to the import and export of energy between distributed generation circuits, i.e., the energy exchange is up to ≈106.8 kW, intending to reduce the energy contribution of the utility electrical network. Finally, the analysis of the Active Buildings showed an increase in the net generation forecast, up to ≈2.25 MW.
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Yin, Hongmei, Likai Hu, Yang Li, Yulie Gong, Yanping Du, Chaofan Song, and Jun Zhao. "Application of ORC in a Distributed Integrated Energy System Driven by Deep and Shallow Geothermal Energy." Energies 14, no. 17 (September 2, 2021): 5466. http://dx.doi.org/10.3390/en14175466.
Повний текст джерелаАнотація:
This study presents a distributed integrated energy system driven by deep and shallow geothermal energy based on forward and reverse cycle for flexible generation of cold, heat and electricity in different scenarios. By adjusting the strategy, the system can meet the demand of heat-electricity in winter, cool-electricity in summer and electricity in transition seasons. The thermodynamic analysis shows that the thermal efficiency of the integrated energy system in the heating and power generation mode is 16% higher than that in the cooling and power generation mode or the single power generation mode. Meanwhile, the annual heat-obtaining quantity of the system is reduced by 11% compared with that of the independent power generation system, which effectively alleviates the imbalance of the temperature field of the shallow geothermal reservoir. In terms of net power generation, the integrated energy system can generate approximately 31% more electricity than the conventional independent cooling and heating system under the same cooling and heating capacity. An integrated system not only realizes the comprehensive supply of cold and thermal ower by using clean geothermal efficiency, but also solves the temperature imbalance caused by the attenuation of a shallow geothermal temperature field. It provides a feasible way for carbon emission reduction to realize sustainable and efficient utilization of geothermal energy.
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Das, Mehmet, and Oguzhan Pektezel. "Experimental and numerical comparison of thermodynamic performances of new and old generation refrigerants in the same cooling system." Thermal Science, no. 00 (2022): 69. http://dx.doi.org/10.2298/tsci220205069d.
Повний текст джерелаАнотація:
The use of new generation low GWP refrigerants in cooling systems is becoming increasingly common due to thermal performance and less environmental impact. In this study, the thermal performance of the new generation R290 refrigerant and the old generation R404A refrigerant in the same cooling system were investigated experimentally and numerically. The thermal performance values of both gases were compared, provided that the temperature of the cold room cooled by the vapor compression cooling system drops to 0?C. -5?C, 0?C, 5?C evaporator temperatures and 25?C, 30?C, 35?C condenser temperatures were used as operating parameters. The experimental results revealed that the highest COP values in the system for R290 and R404A were 4.68 and 3.94, respectively. An average of 9.38 % increase in cooling capacity was detected with R290 compared to R404A refrigerant. In the numerical analysis part of the study, the evaporator surface temperature and air velocity distributions of both refrigerants in the cold room were shown numerically by using Ansys Fluent 19.1. As a result of the study, it was stated that R290 had higher thermal performance than R404A, according to both experimental and numerical analysis results.
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Трушляков, Євген Іванович, Андрій Миколайович Радченко, Микола Іванович Радченко, Сергій Георгійович Фордуй, Сергій Анатолійович Кантор та Богдан Сергійович Портной. "МЕТОДОЛОГІЧНІ ПІДХОДИ ДО ВИЗНАЧЕННЯ ХОЛОДОПРОДУКТИВНОСТІ СИСТЕМ КОНДИЦІЮВАННЯ ПОВІТРЯ ЗА ЗМІННИХ КЛІМАТИЧНИХ УМОВ". Aerospace technic and technology, № 7 (31 серпня 2019): 71–75. http://dx.doi.org/10.32620/aktt.2019.7.09.
Повний текст джерелаАнотація:
One of the most attractive reserves for improving the energy efficiency of air conditioning systems is to ensure the operation of refrigeration compressors in nominal or close to nominal modes by selecting a rational design heat load and distributing it within its design value according to the behavior of the current heat load under variable current climatic conditions to provide the maximum or close to maximum annual cooling capacity generation according to cooling duties of air conditioning. In the general case, the overall range of current thermal loads of any air conditioning system includes a range of unstable loads associated with the precooling of ambient air with significant fluctuations in cooling capacity according with current climatic conditions, and a relatively stable range of cooling capacity consumed to further reduce air temperature from a certain threshold temperature to the final outlet temperature. It is quite obvious that a stable range of heat load can be ensured within operating a conventional compressor in a mode close to the nominal mode while precooling the ambient air with significant fluctuations in heat load requires regulation of the cooling capacity through the use of a variable speed compressor. Thus, in response of the behavior of the change in current heat loads, any air conditioning system, whether the central air-conditioning system with its heat procession in a central air conditioner, or a combination thereof with a local recirculation system of indoor air, essentially consists of two subsystems: pre-cooling the ambient air and then cooling it to the set point temperature. The proposed method of distribution of design heat load depending on the behavior of the current heat load is useful for the rational design of central air conditioning systems and their combined versions with the local air conditioning system.
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Gulevsky, Vyacheslav, and Vyacheslav Makovichko. "Thermal balance of greenhouse complexes of the V generation in the summer period." BIO Web of Conferences 42 (2022): 02008. http://dx.doi.org/10.1051/bioconf/20224202008.
Повний текст джерелаАнотація:
When growing various crops in greenhouses an important condition for obtaining high yields is compliance with the required parameters of the temperature regime of the air environment. The air conditioning systems currently used in greenhouses of the V generation “Ultra Clima” are equipped with adiabatic panels that cool the air entering the room by evaporation of moisture from their surface. However, in some cases, such systems are not able to support the required values. This is due to the large heat flows entering the greenhouse in the summer. The paper analyzes the temperature balance of the air environment of greenhouses of the V generation, evaluates the main heat flows, determines the operating modes of cooling systems that guarantee sufficient cooling capacity to achieve the required temperatures in the room.
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Asim, Muhammad, and Farooq Riaz Siddiqui. "Hybrid Nanofluids—Next-Generation Fluids for Spray-Cooling-Based Thermal Management of High-Heat-Flux Devices." Nanomaterials 12, no. 3 (February 1, 2022): 507. http://dx.doi.org/10.3390/nano12030507.
Повний текст джерелаАнотація:
In recent years, technical advancements in high-heat-flux devices (such as high power density and increased output performance) have led to immense heat dissipation levels that may not be addressed by traditional thermal fluids. High-heat-flux devices generally dissipate heat in a range of 100–1000 W/cm2 and are used in various applications, such as data centers, electric vehicles, microelectronics, X-ray machines, super-computers, avionics, rocket nozzles and laser diodes. Despite several benefits offered by efficient spray-cooling systems, such as uniform cooling, no hotspot formation, low thermal contact resistance and high heat transfer rates, they may not fully address heat dissipation challenges in modern high-heat-flux devices due to the limited cooling capacity of existing thermal fluids (such as water and dielectric fluids). Therefore, in this review, a detailed perspective is presented on fundamental hydrothermal properties, along with the heat and mass transfer characteristics of the next-generation thermal fluid, that is, the hybrid nanofluid. At the end of this review, the spray-cooling potential of the hybrid nanofluid for thermal management of high-heat-flux devices is presented.
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Nogueira, Élcio. "Entropy generation analysis in a gasket plate heat exchanger using non-spherical shape of alumina boehmite nanoparticles." Ovidius University Annals of Chemistry 33, no. 1 (January 1, 2022): 41–49. http://dx.doi.org/10.2478/auoc-2022-0006.
Повний текст джерелаАнотація:
Abstract The analysis deals with the thermo-hydraulic performance of a Gasket Plate Heat Exchanger used for cooling vegetable oils with a water-ethylene glycol 50% and volume fractions of non-spherical nanoparticles mixture as a refrigerant. The heat exchanger has 75 plates with a chevron angle equal to 30º. The Reynolds number of the refrigerant varies from 80 to 1530. The Reynolds number of the sunflower vegetable oil is fixed and equal to 30. The non-spherical nanoparticles used for analysis are platelet, cylindrical and brick types. Graphical results are presented for global heat transfer coefficient, heat capacity ratio, heat transfer rate, outlet temperatures, thermal and viscous entropy generation rate, and Bejan thermodynamic number. The results obtained allow us to conclude that it is possible to work with low relative flow rates using non-spherical nanoparticles, emphasizing platelet nanoparticles. The entropy generations analysis shows that very high flow rates of the refrigerant dissipate much of the energy in viscous form and do not contribute to oil cooling, with a consequent increase in the heat exchanger operating costs.
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Rezaee, Vahid, and Arash Houshmand. "Feasibility Study Of Maisotsenko Indirect Evaporative Air Cooling Cycle In Iran." GeoScience Engineering 61, no. 2 (June 1, 2015): 23–36. http://dx.doi.org/10.1515/gse-2015-0015.
Повний текст джерелаАнотація:
Abstract This paper presents energy and exergy analysis of air cooling cycle based on novel Maisotsenko indirect evaporative cooling cycle. Maisotsenko cycle (M-cycle) provides desired cooling condition above the dew point and below the wet bulb temperature. In this study, based on average annual temperature, The Iran area is segmented into eleven climates. In energy analysis, wet-bulb and dew point effectiveness, cooling capacity rate and in exergy analysis, exergy input rate, exergy destruction rate, exergy loss, exergy efficiency, exergetic COP and entropy generation rate for Iran's weather conditions in the indicated climates are calculated. Moreover, a feasibility study based on water evaporation rate and Maisotsenko cycle was presented. Energy and exergy analysis results show that the fifth, sixth, seventh and eighth climates are quite compatible and Rasht, Sari, Ramsar and Ardabile cities are irreconcilable with the Maisotsenko cycle.
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Adiprana, Reza, Danu Sito Purnomo, and Iwan Setiono. "Kamojang Geothermal Power Plant Unit-1 : 30 Years of Operation." Applied Mechanics and Materials 493 (January 2014): 56–61. http://dx.doi.org/10.4028/www.scientific.net/amm.493.56.
Повний текст джерелаАнотація:
UNIT-1 KAMOJANG geothermal power plant marked the new era of renewable energy in Indonesia. With its built capacity of 30 MWe, it constantly supply electricity to Java-Bali grid for more than 30 years now.Over those period, Unit-1 has given its best performance with highest achievement on Capacity Factor (CF) and Equivalent Availability Factor (EAF).High performance geothermal power plant involves the integration not only from the point of view of power generation, but also the optimation of geothermal potention in the area. Kamojang geothermal field, which is considered as one among five steam dominated reservoir in the world produces 200 MWe of the electricity nowadays. In order to maintain this production rate, some technical consideration must be made.Towards sustainable power generation of geothermal power, some assessment has been made to turbine, generator and cooling tower to ensure its current condition. Basically what it called remaining life assessment gives a rough picture of how long the equipment will run through in its operational condition.Based on those assessment, additional 20.900 hours is given to the turbine with the existing operating conditions. On the other hand, cooling tower infrastucture test and simulation delivers operation period for another 25 years.
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Choi, Junwon, and Rin Yun. "Operation Strategy and Parametric Analysis of a CHP and a Tri-Generation System for Integrated Community." International Journal of Air-Conditioning and Refrigeration 23, no. 01 (March 2015): 1550001. http://dx.doi.org/10.1142/s2010132515500017.
Повний текст джерелаАнотація:
Thermal efficiencies of Combined Heat and Power (CHP) and Tri-generation system, which are installed in a residential district and a general hospital, respectively, are investigated by using RETScreen. Economic feasibility and amount of CO 2 reduction are also estimated by comparing them with separate energy system, which separately supplies electricity, heating and cooling energy to consumer. When power generation capacity of the CHP system is changed from 26 to 40 MW, the efficiency is the highest at 26 MW. It is found that equity payback period is 5.7 years. Power generation capacity of the Tri-generation system for a general hospital was estimated to be 3.2 MW. Depending on the insulation amount of the building, profits and operating efficiency of the Tri-generation system are significantly changed. As an operating strategy, the type of following electricity load shows the highest thermal efficiency of 86%. When cost of electricity is raised by 10% and 20% of the present price, simple payback period is reduced from 5.2 years to 3.0 and 2.1 years, respectively.
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Sheremet, Mikhail, Hakan Oztop, Dmitriy Gvozdyakov, and Mohamed Ali. "Impacts of Heat-Conducting Solid Wall and Heat-Generating Element on Free Convection of Al2O3/H2O Nanofluid in a Cavity with Open Border." Energies 11, no. 12 (December 7, 2018): 3434. http://dx.doi.org/10.3390/en11123434.
Повний текст джерелаАнотація:
Development of modern electronic devices demands a creation of effective cooling systems in the form of active or passive nature. More optimal technique for an origination of such cooling arrangement is a mathematical simulation taking into account the major physical processes which define the considered phenomena. Thermogravitational convection in a partially open alumina-water nanoliquid region under the impacts of constant heat generation element and heat-conducting solid wall is analyzed numerically. A solid heat-conducting wall is a left vertical wall cooled from outside, while a local solid element is placed on the base and kept at constant volumetric heat generation. The right border is supposed to be partially open in order to cool the local heater. The considered domain of interest is an electronic cabinet, while the heat-generating element is an electronic chip. Partial differential equations of mathematical physics formulated in non-primitive variables are worked out by the second order finite difference method. Influences of the Rayleigh number, heat-transfer capacity ratio, location of the local heater and nanoparticles volume fraction on liquid circulation and thermal transmission are investigated. It was ascertained that an inclusion of nanosized alumina particles to the base liquid can lead to the average heater temperature decreasing, that depends on the heater location and internal volumetric heat generation. Therefore, an inclusion of nanoparticles inside the host liquid can essentially intensify the heat removal from the heater that is the major challenge in different engineering applications. Moreover, an effect of nanosized alumina particles is more essential in the case of low intensive convective flow and when the heater is placed near the cooling wall.
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Park, Moon-Woo, and Don-Mook Choi. "Experimental Study on Prevention of Thermal Runaway Propagation in Pouch-type Lithium-ion Batteries." Fire Science and Engineering 35, no. 6 (December 31, 2021): 30–36. http://dx.doi.org/10.7731/kifse.6487b16b.
Повний текст джерелаАнотація:
In this study, thermal runaway propagation characteristics and measures to prevent this phenomenon were analyzed by applying abnormal thermal conditions to pouch-type lithium-ion batteries. Experiments were conducted in a 1.5 m × 1.5 m × 1.5 m experimental chamber. During the experiment, pouch-type lithium-ion batteries were grouped according to capacity, quantity, and the use of fire extinguishing agents. Experiments showed that when thermal runaway occurred in a cell, it propagated to the adjacent cell after a certain period. The surface temperature of the cell where thermal runaway first occurred was above 200 ℃, and thermal runaway propagated via heat transfer to the adjacent cell. In the case of thermal runaway, when a fire extinguishing agent was applied, the propagation of thermal runaway to adjacent cells was prevented due to a cooling effect. However, at a cell capacity of 100 Ah, flame generation persisted and thermal runaway was unavoidable. To prevent thermal runaway propagation, it is necessary to select an extinguishing agent that exerts a cooling effect. The capacity and structure of the model unit should be considered when installing fire extinguishing systems.
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Malinina, O. S., A. V. Baranenko, M. A. Al-Furaiji, E. E. Lydova, and K. A. Komarov. "Efficiency of lithium bromide absorption chiller with multi-stage absorption and generation processes with associated mass flow." Omsk Scientific Bulletin. Series Aviation-Rocket and Power Engineering 5, no. 2 (2021): 9–17. http://dx.doi.org/10.25206/2588-0373-2021-5-2-9-17.
Повний текст джерелаАнотація:
A study of the cycles of a lithium bromide–water absorption chiller with two-stage absorption and three-stage generation of a working substance vapor with an associated mass flow with different supply of the cooling medium to the apparatus has been carried out. The temperature of the heating source necessary for the implementation of the actual thermodynamic cycle of the Lithium Bromide– Water Absorption Chiller (LBWAC) and the most effective thermodynamic cycle has been determined. A comparative analysis of the cycle understudy with the sample cycle (one-stage cycle) LBWAC is carried out. Despite the lower values of the coefficient of performance (COP), the cycle under study provides a doubling of the cooling capacity of the machine, at the same flow rate of the heating source, which is an advantage when the flow rate of the heating source is limited. This circumstance is explained by the fact that in LBWAC with multi-stage absorption and generation, the heating source sequentially passes through three generator stages. Therefore, the degree of cooling in the chiller with the considered cycle is three times higher than this value of a single-stage LBWAC
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Fan, Xuchen, Xiaofeng Lu, Jiping Wang, Zilong Li, Quanhai Wang, Zhonghao Dong, and Rongdi Zhang. "Performance Evaluation of a Maisotsenko Cycle Cooling Tower with Uneven Length of Dry and Wet Channels in Hot and Humid Conditions." Energies 14, no. 24 (December 8, 2021): 8249. http://dx.doi.org/10.3390/en14248249.
Повний текст джерелаАнотація:
The use of the Maisotsenko cycle (M-Cycle) in traditional wet cooling towers (TWCTs) has the potential to reduce the costs of electricity generation by cooling water below the inlet air’s wet-bulb temperature. TWCTs cannot provide sufficient cooling capacity for the increasing demand for cooling energy in the power and industrial sectors—especially in hot and wet climates. Due to this fact, an experimental system of an M-Cycle cooling tower (MCT) with parallel counter-flow arrangement fills was constructed in order to provide perspective on the optimal length of dry channels (ldry), thermal performance under different conditions, and pressure drops of the MCT. Results showed that the optimal value of ldry was 2.4 m, and the maximum wet-bulb effectiveness was up to 180%. In addition, the impact of air velocity in wet channels on the pressure drops of the novel fills was also summarized. This study confirms the great potential of using the M-Cycle in TWCTs, and provides a guideline for the industrial application and performance improvement of MCTs.
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Muthaiyan, Kesavan, Rajamani Narayanasamy, Chidambaram Lakshmanan, Pandiyarajan Vellaichamy, and Velraj Ramalingam. "Residential Air Conditioning System Integrated with Packed Bed Cool Storage Unit for Promoting Rooftop Solar PV Power Generation." International Journal of Renewable Energy Development 10, no. 2 (May 1, 2020): 239–47. http://dx.doi.org/10.14710/ijred.2021.33750.
Повний текст джерелаАнотація:
The increase in the share of renewable-based power in the gross power generation in most countries causes significant concerns over the addition of renewable power with the grid, results in stability issues in most developed nations. Energy storage is an emerging technology that is considered the ultimate solution in developing microgrids with distributed renewable power generation. The cool thermal storage plays a vital role in economically promoting renewable power among different storage units. The major objective of the research work is to demonstrate the integration of residential air-conditioning systems with packed bed cool storage units to promote rooftop solar power generation for residential space cooling applications. In order to achieve the said objective, an experimental investigation was made to study the charging/discharging characteristics of a packed bed cool-storage unit combined with a chiller and a cooling coil unit suitable for small capacity air-conditioning applications. The system consists of encapsulated spherical capsules filled with a phase change material blended with distilled water and pseudomonas (nucleating agent) and the heat transfer fluid as a combination of distilled water and Mono-ethylene glycol. A cooling coil unit was connected to the cool-storage tank to transfer cool energy from the storage tank to the space to be cooled when there is a demand. The important parameters, such as instantaneous and cumulative heat transfer during the charging/discharging processes, are presented. The average COP values of the chiller during the charging operation were estimated as 1, 0.93, and 0.89 when the HTF setpoint temperatures were -6°C, -9°C, and -12°C, which shows a decrease in performance as the setpoint temperature decreases. During the discharging process, a cooling load of 2.25 kW is obtained during the first cycle of operation and gradually reduces to 0.3 kW during the sixth cycle of operation. The increase in the HTF temperature during each cycle of operation indicates that the Phase Change Material (PCM) in the balls cannot release the heat as per the demand after a certain period of discharging. Hence, decreasing the internal thermal resistance by suitable measures is essential to achieve uniform heat flux and to operate the system successfully
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Somasundaram, S., M. K. Drost, D. R. Brown, and Z. I. Antoniak. "Coadunation of Technologies: Cogeneration and Thermal Energy Storage." Journal of Engineering for Gas Turbines and Power 118, no. 1 (January 1, 1996): 32–37. http://dx.doi.org/10.1115/1.2816546.
Повний текст джерелаАнотація:
Thermal energy storage can help cogeneration meet the energy generation challenges of the 21st century by increasing the flexibility and performance of cogeneration facilities. Thermal energy storage (TES) allows a cogeneration facility to: (1) provide dispatchable electric power while providing a constant thermal load, and (2) increase peak capacity by providing economical cooling of the combustion turbine inlet air. The particular systems that are considered in this paper are high-temperature diurnal TES, and TES for cooling the combustion turbine inlet air. The paper provides a complete assessment of the design, engineering, and economic benefits of combining TES technology with new or existing cogeneration systems, while also addressing some of the issues involved.
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Buffa, Simone, Anton Soppelsa, Mauro Pipiciello, Gregor Henze, and Roberto Fedrizzi. "Fifth-Generation District Heating and Cooling Substations: Demand Response with Artificial Neural Network-Based Model Predictive Control." Energies 13, no. 17 (August 21, 2020): 4339. http://dx.doi.org/10.3390/en13174339.
Повний текст джерелаАнотація:
District heating and cooling (DHC) is considered one of the most sustainable technologies to meet the heating and cooling demands of buildings in urban areas. The fifth-generation district heating and cooling (5GDHC) concept, often referred to as ambient loops, is a novel solution emerging in Europe and has become a widely discussed topic in current energy system research. 5GDHC systems operate at a temperature close to the ground and include electrically driven heat pumps and associated thermal energy storage in a building-sited energy transfer station (ETS) to satisfy user comfort. This work presents new strategies for improving the operation of these energy transfer stations by means of a model predictive control (MPC) method based on recurrent artificial neural networks. The results show that, under simple time-of-use utility rates, the advanced controller outperforms a rule-based controller for smart charging of the domestic hot water (DHW) thermal energy storage under specific boundary conditions. By exploiting the available thermal energy storage capacity, the MPC controller is capable of shifting up to 14% of the electricity consumption of the ETS from on-peak to off-peak hours. Therefore, the advanced control implemented in 5GDHC networks promotes coupling between the thermal and the electric sector, producing flexibility on the electric grid.
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Setyono, Gatot, Navik Kholili, and Yanuariza Rakhmadanu. "The Impact of Utilization The Solar-Panels With a Cooling-Water System as a Source of Micro-Power Generation." Infotekmesin 13, no. 1 (January 22, 2022): 87–92. http://dx.doi.org/10.35970/infotekmesin.v13i1.1001.
Повний текст джерелаАнотація:
The optimal approach to enhance solar panel efficiency and decrease the degradation rate is to lower the temperature range of the surface area. It will be applied by allowing the panels/modules to be cooled and lessening the heat stored in the solar cells through an operation. In the research using experimental methods, the solar panels used have a capacity of 100 WP as a source of micro-power generation, the angle of inclination of the panels is adjusted with variations of 150, 200, and 250. The cooling system uses water, the process of draining water using a submersible pump mounted on a reservoir Water flows to all surfaces of the solar panel and circulates continuously when operating. The experimental outcomes show that the cooling process utilizing water has reduced the temperature operating of the solar panels. The decrease in average temperature occurred in all variations of 23%. The cooling process significantly affects the output power and operational efficiency; circulating cooling can increase the scale of incidents solar radiation on the solar panel due to the refractive effect of the water layer and keep the surface of the solar panel clean from dirt and dust. Output power and operational efficiency have increased in almost all variations in the angle of the solar panel tilt (150, 200, and 250), output power has increased by an average of 22%, and efficiency has increased by on average of 2%
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Galindo Luna, Yuridiana, Wilfrido Gómez Franco, Ulises Dehesa Carrasco, Rosenberg Romero Domínguez, and José Jiménez García. "Integration of the Experimental Results of a Parabolic Trough Collector (PTC) Solar Plant to an Absorption Air-Conditioning System." Applied Sciences 8, no. 11 (November 5, 2018): 2163. http://dx.doi.org/10.3390/app8112163.
Повний текст джерелаАнотація:
The present study reports the experimental results of a parabolic trough collector field and an absorption cooling system with a nominal capacity of 5 kW, which operates with the ammonia-lithium nitrate mixture. The parabolic trough collectors’ field consists of 15 collectors that are made of aluminum plate in the reflector surface and cooper in the absorber tube, with a total area of 38.4 m2. The absorption cooling system consists of 5 plate heat exchangers working as the main components. Parametric analyses were carried out to evaluate the performance of both systems under different operating conditions, in independent way. The results showed that the solar collectors’ field can provide up to 6.5 kW of useful heat to the absorption cooling system at temperatures up to 105 °C with thermal efficiencies up to 19.8% and exergy efficiencies up to 14.93, while the cooling system operated at generation temperatures from 85–95 °C and condensation temperatures between 20 and 28 °C, achieving external coefficients of performance up to 0.56, cooling temperatures as low as 6 °C, and exergy efficiencies up to 0.13. The highest value for the solar coefficient of performance reached 0.07.
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Sohani, Ali, Mohammad Hassan Shahverdian, Hoseyn Sayyaadi, Siamak Hoseinzadeh, Saim Memon, Giuseppe Piras, and Davide Astiaso Garcia. "Energy and Exergy Analyses on Seasonal Comparative Evaluation of Water Flow Cooling for Improving the Performance of Monocrystalline PV Module in Hot-Arid Climate." Sustainability 13, no. 11 (May 28, 2021): 6084. http://dx.doi.org/10.3390/su13116084.
Повний текст джерелаАнотація:
Solar irradiation in hot-arid climatic countries results in increased temperatures, which is one of the major factors affecting the power generation efficiency of monocrystalline photovoltaic (PV) systems, posing performance and degradation challenges. In this paper, the efficiency of a water-flow cooling system to increase the output of a monocrystalline PV module with a rated capacity of 80 W is studied from both energy and exergy perspectives. The energy and exergy tests are performed for each season of the year, with and without cooling. The energy and exergy efficiencies, as well as the commodity exergy values, are used to compare the photovoltaic device with and without cooling. The findings are based on the experimental data that were collected in Tehran, Iran as an investigated case study in a country with a hot-arid climate. The findings show that when water-flow cooling is used, the values of the three efficiency metrics change significantly. In various seasons, improvements in regular average energy efficiency vary from 7.3% to 12.4%. Furthermore, the achieved increase in exergy efficiency is in the 13.0% to 19.6% range. Using water flow cooling also results in a 12.1% to 18.4% rise in product exergy.
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Singh, Preeti, Sourav Khanna, Sanjeev Newar, Vashi Sharma, K. Reddy, Tapas Mallick, Victor Becerra, Jovana Radulovic, David Hutchinson, and Rinat Khusainov. "Solar Photovoltaic Panels with Finned Phase Change Material Heat Sinks." Energies 13, no. 10 (May 18, 2020): 2558. http://dx.doi.org/10.3390/en13102558.
Повний текст джерелаАнотація:
Phase change material (PCM) based passive cooling of photovoltaics (PV) can be highly productive due to high latent heat capacity. However, the low rate of heat transfer limits its usefulness. Thus, the presented work aims at the improvement in PV cooling by using finned PCM (FPCM) heat sinks. In the present study, PCM heat sink and FPCM heat sinks were investigated numerically for PV cooling and the extracted heat is used for space heating. 4 kWp PV, PV-PCM and PV-FPCM systems were studied under the weather conditions of Southeast of England. It was observed that the PCM heat sinks can drop the peak PV temperature by 13 K, whereas FPCM heat sinks can enhance the PV cooling by 19 K. The PCM heat sinks can increase the PV electrical efficiency from 13% to 14%. Moreover, the daily electricity generation can be boosted by 7% using PCM and 8% by using FPCM heat sinks. In addition, 7 kWh of thermal output was achieved using the FPCM heat sink, and the overall efficiency of system increased from 13% to 19%.
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Shamshir Ali, Tanti Zanariah, Abu Bakar Rosli, Gan Leong Ming, Billy Anak Sup, and Mohd Farid Zainudin. "Study on Potential Waste Insulating Material Properties in Water for Thermal Storage Application." Advanced Materials Research 903 (February 2014): 139–44. http://dx.doi.org/10.4028/www.scientific.net/amr.903.139.
Повний текст джерелаАнотація:
Energy is a continuous driving power for the social and technological development. Developing thermal energy storage(TES) is a competent way to provide continuous power generation. The key issue in designing the TES system is its thermal capacity of storage materials. This study is focusing on the potential waste material as an insulator for thermal energy storage applications. The insulator usage is to reduce the heat transfer between two medium and the capability is measured by its heat flow resistance. The bigger the value, the more blocking capacity or insulating it provides. It is needed to find optimal material to energy conversion at the same time reduce the waste generation. Therefore, a small-scale experimental testing of natural cooling process of an insulated tank within a confined room without any forced cooling system, e.g. fan. The testing is repeated by changing the insulator using the potential waste material from natural and industrial waste. The analysis is performed on the relationship between heat loss and the reserved period by the insulator. The results represent the percentage of period of the insulated tank withstand the heat compared to non-insulated tank, e.g. cotton reserved the period of 19% more than non-insulated tank to withstand the heat transfer of water to the surrounding. The paper finally justifies that cotton is the most potential waste material as an insulator in water.
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Elias, M. A., R. M. Jais, N. Muda, N. A. Azlin, and N. M. Ahmad. "Research on Different Types of Cooling System on Ground Mounted Solar Photovoltaic System for Electrical Output Enhancement." Journal of Physics: Conference Series 2051, no. 1 (October 1, 2021): 012071. http://dx.doi.org/10.1088/1742-6596/2051/1/012071.
Повний текст джерелаАнотація:
Abstract Solar photovoltaic (PV) can be used to generate power by using semiconductor materials to convert solar energy into electricity. In Malaysia, solar PV technology plays a significant role in increasing renewable energy generation capacity target at 20% by 2025. Malaysia’s strategic location at the equator makes it possible to achieve this target. However, several challenges need to be mitigated when implementing this technology, among others is the effect of temperature on solar PV system performance. Solar PV panel is currently rated at a range of efficiency between 13% to 20%. The efficiency of the PV panel is affected by temperature where the PV power and efficiency decrease at the rate of -0.5%/°C and -0.05%/°C respectively as the ambient temperature increases. This study aims to evaluate the effectiveness of different types of PV cooling systems in reducing the solar PV panel temperature. In this study, the PV systems were retrofitted by two types of cooling system which are passive cooling and active cooling systems. The results of panel temperatures were measured against the control system without the cooling mechanism. The research was conducted in real operating condition with direct sunlight. Active cooling system reduced the temperature of the PV system and improved the electrical output by 4.9% while the best passive cooling system improved the output by 3%. Factors contributing to the results are also discussed in this paper.
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Garimella, S., and V. S. Garimella. "Commercial Boiler Waste-Heat Utilization for Air Conditioning in Developing Countries." Journal of Energy Resources Technology 121, no. 3 (September 1, 1999): 203–8. http://dx.doi.org/10.1115/1.2795983.
Повний текст джерелаАнотація:
This study investigates the utilization of waste heat from commercial process steam boilers for air conditioning using absorption cooling systems. An ammonia-water generator absorber heat exchange system was developed and modeled to use waste heat from the boiler flue gases and deliver chilled water. Based on approximately 1000 process steam boilers at an average throughput of 2000 kg/h in one metropolitan area in India, the study estimates that installation of these systems could result in annual operating cost savings of $10,200,000 in this region alone. These 1000 systems would also reduce the installed electric capacity needs by 16 MW. Annual coal consumption would decrease by 87,000 tonnes, while ash production would decrease by 39,000 tonnes. Carbon-based emissions are estimated to decrease by 176,000 tonnes. Therefore, installation of these systems on a countrywide basis and also in other developing countries with high year-round cooling loads and coal-based power generation would significantly alleviate installed power capacity shortages, conserve energy resources, and reduce greenhouse gas emissions.
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Eveloy, Valérie, Peter Rodgers, and Sahil Popli. "Power generation and cooling capacity enhancement of natural gas processing facilities in harsh environmental conditions through waste heat utilization." International Journal of Energy Research 38, no. 15 (April 26, 2014): 1921–36. http://dx.doi.org/10.1002/er.3197.
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Kahraman, Gökhan. "Increasing the Power Generation by Raising the Capacity of the Thrust Bearing Oil Cooling System in Hydroelectric Power Plants." Journal of Failure Analysis and Prevention 20, no. 4 (August 2020): 1445–49. http://dx.doi.org/10.1007/s11668-020-00969-9.
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Ali Sohani, Mohammad Hassan Shahverdian, Hoseyn Sayyaadi, Siamak Hoseinzadeh, and Saim Memon. "Enhancing the renewable energy payback period of a photovoltaic power generation system by water flow cooling." International Journal of Solar Thermal Vacuum Engineering 3, no. 1 (August 25, 2021): 73–85. http://dx.doi.org/10.37934/stve.3.1.7385.
Повний текст джерелаАнотація:
A photovoltaic system which enjoys water flow cooling to enhance the performance is considered, and the impact of water flow rate variation on energy payback period is investigated. The investigation is done by developing a mathematical model to describe the heat transfer and fluid flow. A poly crytalline PV module with the nomical capacity of 150 W that is located in city Tehran, Iran, is chosen as the case study. The results show that by incresing water flow rate, EPBP declines first linearly, from the inlet water flow rate of 0 to 0.015 kg.s-1, and then, EPBP approaches a constant value. When there is no water flow cooling, EPBP is 8.88, while by applying the water flow rate of 0.015 kg.s-1, EPBP reaches 6.26 years. However, only 0.28 further years decreament in EPBP is observed when the inlet water mass flow rate becomes 0.015 kg.s-1. Consequently, an optimum limit for the inlet water mass flow rate could be defined, which is the point the linear trend turns into approaching a constant value. For this case, as indicated, this value is 0.015 kg.s-1.
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Bayoumi, Mohannad. "Potential of integrating power generation with solar thermal cooling to improve the energy efficiency in a university campus in Saudi Arabia." Energy & Environment 31, no. 1 (August 29, 2018): 130–54. http://dx.doi.org/10.1177/0958305x18787271.
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Along with the rapid ongoing developments and expansions of the King Abdulaziz University campus, it is sensible to rethink the way electrical and cooling energy is generated and to explore methods to increase energy efficiency in the academic facilities. A conceptual energy master plan for the entire campus has been developed to achieve feasible results which require a substantial reduction in energy demand in the first place. It combines strategies at the master plan level and the micro level (case study: a single building). Establishing a correlating link between the macro and the micro level is imperative to improve the efficiency of the total system. Therefore, possibilities for centralized and decentralized (building related) energy generation have also been investigated to improve the efficiency of the total system. After outlining the general strategies for renewable energy generation on the master plan level in the university campus of King Abdulaziz University, this study explores the potential of increasing the energy efficiency of an individual building. Key energy saving actions have been simulated using IDA-ICE to assess the possibility to release the load on the shared existing and future energy infrastructure. Besides roof-integrated solar panels, the capacity of carport incorporated energy generation has also been analyzed. The results of the study indicate possible substantial savings on the current consumption of non-renewable energy resources and a combined generation of electrical energy and solar thermal cooling can lead to high coverage fraction.
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Liu, Qingjun, Fei Cao, Yanhua Liu, Tianyu Zhu, and Deyou Liu. "Design and Simulation of a Solar Chimney PV/T Power Plant in Northwest China." International Journal of Photoenergy 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/1478695.
Повний текст джерелаАнотація:
A solar chimney PV/T power plant (SCPVTPP) is proposed. Mathematical models are established for the PV/T solar collector, the chimney, and the power conversion unit, respectively. Performances of the designed SCPVTPP are then simulated. The SCPVTPPs with different PV module areas are finally discussed. It is found that the PV cells hold the highest temperature in the solar collector. Temperature rise of the PV module has significant influences to its power generation. Without cooling, the PV power capacity has an average decrease of 28.71%. The contradictory influences of temperature rise and airflow cooling lead to an 11.81% decrease of the average power capacity. By adding the power generated by PVT, the total PV-related power contribution increases by 4.72%. With the increase of the solar collector ratio, the temperature rise and the wind velocity both first decrease then increase, the SCPP power productivity decreases linearly, and the PV power productivity increases linearly, whereas the PVT power productivity first increases linearly then increases superlinearly. There is a reversed solar collector ratio, exceeding which the PV generates most power. In this study, solar thermal power takes the major role when the solar PV area ratio is smaller than 0.055.
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Costa, Raphael Camargo da, Cesar Augusto Arezo e. Silva Jr., Júlio Cesar Costa Campos, Washington Orlando Irrazabal Bohorquez, Rogerio Fernandes Brito, and Antônio M. Siqueira. "A technical-economic analysis of turbine inlet air cooling for a heavy duty gas turbine operating with blast-furnace gas." Research, Society and Development 10, no. 9 (July 29, 2021): e59810915006. http://dx.doi.org/10.33448/rsd-v10i9.15006.
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The study was developed inside an integrated steel mill, located in Rio de Janeiro city, aiming to analyse the technical-economic feasibility of installing a new inlet air refrigeration system for the gas turbines. The technologies applied for such purpose are named Turbine Inlet Air Cooling (TIAC) technologies. The power plant utilizes High Fogging and Evaporative Cooling methods for reducing the compressor’s inlet air temperature, however, the ambient climate condition hampers the turbine’s power output when considering its design operation values. Hence, this study was proposed to analyse the installation of an additional cooling system. The abovementioned power plant has two heavy-duty gas turbines and one steam turbine, connected in a combined cycle configuration. The cycle nominal power generation capacity is 450 MW with each of the gas turbines responsible for 90 MW. The gas turbines operate with steelwork gases, mainly blast furnace gas (BFG), and natural gas. The plant has its own weather station, which provided significant and precise data regarding the local climate conditions over the year of 2017. An in-house computer model was created to simulate the gas turbine power generation and fuel consumption considering both cases: with the proposed TIAC system and without it, allowing the evaluation of the power output increase due to the new refrigeration system. The results point out for improvements of 4.22% on the power output, corresponding to the electricity demand of approximately 32960 Brazilian homes per month or yearly earnings of 3.92 million USD.
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Aggarwal, Vivek, Chandan Swaroop Meena, Ashok Kumar, Tabish Alam, Anuj Kumar, Arijit Ghosh, and Aritra Ghosh. "Potential and Future Prospects of Geothermal Energy in Space Conditioning of Buildings: India and Worldwide Review." Sustainability 12, no. 20 (October 13, 2020): 8428. http://dx.doi.org/10.3390/su12208428.
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This paper presents modern trends in geothermal energy utilization, mainly focusing on ground source heat (GSH) pumps for space conditioning in buildings. This paper focuses on India along with a general review of studies around the world. Space conditioning of a building contributes to about 40–50% of the total energy consumed in buildings and has an adverse impact on the environment and human health. The India Cooling Action Plan (ICAP) estimates that the demand for electricity for heating and cooling of buildings will increase by over 700% in India at current levels by 2047 with an additional 800 GW of power generation capacity needed just to meet heating and cooling needs by 2050, of which about 70% is required for the residential sector only. It further intensifies as the demand for peak electric load sharply increases in summer because of the extensive use of building air conditioning systems. Researchers across the globe have tried different cooling systems and found that some systems can offer a certain amount of energy-efficient performance, and also occupant comfort. Therefore, this article examines the geothermal potential in buildings for space conditioning by critically reviewing experimental and numerical studies along with the future prospects of GSH pumps.
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Papadimitriou, Aikaterini, Vassilios Vassiliou, Kalliopi Tataraki, Eugenia Giannini, and Zacharias Maroulis. "Economic Assessment of Cogeneration Systems in Operation." Energies 13, no. 9 (May 2, 2020): 2206. http://dx.doi.org/10.3390/en13092206.
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A systematic method to evaluate the economic operating performance of existing combined heat and power (CHP) or combined cooling heat and power (CCHP) generation systems is applied. Two key performance indicators are selected to evaluate both the technical and the economic performance, based on operating recording data; the capacity factor and the capital recovery. The case study for eight projects in Athens is presented with the purpose to reveal the current situation of CHP in Greece and identify reasons that are hindering its penetration. Interesting conclusions were reached from the analysis. Only two out of the eight projects managed to achieve the break-even point in less than four years since the beginning of their operation, while oversizing phenomena were noticed in many cases leading in extremely low capacity factors.