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1
Palamar, A. "Methods and means of increasing the reliability of computerized modular uninterruptible power supply system." Scientific journal of the Ternopil national technical university 99, no. 3 (2020): 133–41. http://dx.doi.org/10.33108/visnyk_tntu2020.03.133.
Abstract:
The problem of development and implementation of a simple and effective method of the rectifiers operation control for the modular uninterruptible DC power supply unit in order to increase its reliability is considered in this paper. The main idea of the method is to control the process of cyclic shifting of the switched-on power modules of the uninterruptible power supply by series switching into operation of each subsequent module from their unloaded reserve and switching out the previous one. The paper presents the control system structure where in addition to the central control module, it is proposed to add the control unit for power modules, which is responsible for implementing the process of their switching on and monitors their condition. In order to investigate the effectiveness of the proposed method, computer simulation model describing the power modules control logic is developed. The Simulink visual modeling environment and the mathematical tools of the Stateflow library component using state and transition diagrams are used in order to develop the simulation model. The developed simulation model is tested and the simulation results are given in the form of time diagrams of state change. The іmplementation of the developed method, due to the uniform reduction of the period during which the power modules of the uninterruptible power supply are on the switched-on loaded state, makes it possible to increase their operating time to failure, which in turn increases its reliability without deteriorating energy efficiency. The simulation results demonstrate the efficiency of the developed algorithm in various system operation modes. Based on the proposed method, hardware and software which is implemented as a part of intelligent computerized control system for uninterruptible DC power supply is created.
2
Rozhkov, Vyacheslav V., Vladimir V. Fedotov, Kirill K. Krutikov, and Sergey G. Butrimov. "Structural modeling of existing and improved control algorithms for thyristor switching devices of uninterruptible power supply units for auxiliary needs of nuclear power plants." Journal Of Applied Informatics 18, no. 2 (March 31, 2023): 116–31. http://dx.doi.org/10.37791/2687-0649-2023-18-2-116-131.
Abstract:
The article analyzes the operation of thyristor automatic switching devices for uninterruptible power supply units of nuclear power plants. They are part of the emergency power supply system for auxiliary electrical equipment with a rated voltage of 0.4 kV. In such a reliable power supply system for especially responsible consumers, alternative networks and backup sources are necessarily used. Typically, groups of consumers for auxiliary needs of nuclear power plants are powered from the inverter network, so that in the event of a shutdown of the backup bypass network, these loads continue to be powered by the uninterruptible power supply unit. It incorporates a charger – a controlled rectifier, a battery pack and a transistor inverter. The transition from one network to another in any direction must be “shockless” in order to avoid the operation of the protections of uninterruptible power units and other electrical protections of the reliable power supply system. If there are failures in the algorithms or their irrational organization, the processes of transition between networks may be accompanied by a violation of uninterrupted power supply or phase-to-phase short circuits. A structural simulation model has been created in the MatLab computer mathematics system for testing transition algorithms for various phase shifts of networks and transition directions. The algorithm of transition between networks for uninterruptible power units of one of the manufacturing companies that supplied equipment to nuclear power plants was analyzed. A safer optimal algorithm for controlling network switching with phase-by-phase control of the current drop in the disconnected network is proposed. The proposals are supported by the results of computer simulations.
3
Liu, Shu Zhen. "Research on Switch Power Module Parallel Operation System." Applied Mechanics and Materials 599-601 (August 2014): 1657–60. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.1657.
Abstract:
Switch power module parallel operation system is one of the technological developing directions of power with high-power output and uninterruptible supply. The paper puts forward a concept to design switch power module parallel operation system, which adopts two TPS5430 chips to compose DC-DC cell parallel and through their load sharing to control chip UCC39002 to implement DC-DC unit outputting equalized current. It succeeds in building experimental prototype.
4
Palamar, A. "Control system simulation by modular uninterruptible power supply unit with adaptive regulation function." Scientific journal of the Ternopil national technical university 98, no. 2 (2020): 129–36. http://dx.doi.org/10.33108/visnyk_tntu2020.02.129.
5
Muranto, Nomon, Atmam, and Zulfahri . "Studi Peralihan Daya Listrik dari PLN ke Generator Set (Genset) Ketika Terjadi Pemadaman dari PLN dengan Uninterruptible Power Supply (UPS) Pada Hotel Grand Elite Pekanbaru." SainETIn 3, no. 1 (December 29, 2018): 9–16. http://dx.doi.org/10.31849/sainetin.v3i1.3026.
Abstract:
Hotel Grand Elite Pekanbaru mendapat suplai daya listrik dari PLN sebesar 1250 kVA dan mempunyai tiga buah unit Generator-set (Genset) kapasitas 500 kVA sebagai back-up suplai daya listrik apabila terjadinya pemadaman listrik dari PLN. Namun demikian penggunaan genset tersebut tidak dapat melayani beban secara cepat dimana hal ini disebabkan adanya kerusakan pada rangkaian Automatic Transfer Switch (ATS). Untuk itu diperlukan rancangan sistem suplai daya tak terputus yang dapat menyuplai beban, khususnya beban emergency dengan menggunakan Uninterruptible Power Supply (UPS). Dari hasil penelitian diperoleh total beban emergency Hotel Grand Elite Pekanbaru sebesar 125,779 kVA terdiri dari beban lift 32,670 kVA dan beban Elite Fitnes Center 67,952 kVA sehingga diperlukan kapasitas UPS sebesar 150 kVA. Penambahan suplai daya UPS sangat cocok karena disamping sebagai solusi akibat kurangnya daya listrik ketika terjadi pemadaman dari PLN dan juga dapat memback-up beban emergency pada Hotel Grand Elite Pekanbaru. Kata kunci : Generator-set, Uninterruptible Power Supply
6
Bakht, Muhammad Paend, Zainal Salam, Mehr Gul, Waqas Anjum, Mohamad Anuar Kamaruddin, Nuzhat Khan, and Abba Lawan Bukar. "The Potential Role of Hybrid Renewable Energy System for Grid Intermittency Problem: A Techno-Economic Optimisation and Comparative Analysis." Sustainability 14, no. 21 (October 28, 2022): 14045. http://dx.doi.org/10.3390/su142114045.
Abstract:
The renewed interest for power generation using renewables due to global trends provides an opportunity to rethink the approach to address the old yet existing load shedding problem. In the literature, limited studies are available that address the load shedding problem using a hybrid renewable energy system. This paper aims to fill this gap by proposing a techno-economic optimisation of a hybrid renewable energy system to mitigate the effect of load shedding at the distribution level. The proposed system in this work is configured using a photovoltaic array, wind turbines, an energy storage unit (of batteries), and a diesel generator system. The proposed system is equipped with a rule-based energy management scheme to ensure efficient utilisation and scheduling of the sources. The sizes of the photovoltaic array, wind turbine unit, and the batteries are optimised via the grasshopper optimisation algorithm based on the multi-criterion decision that includes loss of power supply probability, levelised cost of electricity, and payback period. The results for the actual case study in Quetta, Pakistan, show that the optimum sizes of the photovoltaic array, wind turbines, and the batteries are 35.75 kW, 10 kW, and 28.8 kWh, respectively. The sizes are based on the minimum values of levelised cost of electricity (6.64 cents/kWh), loss of power supply probability (0.0092), and payback period (7.4 years). These results are compared with conventional methods (generators, uninterruptible power supply, and a combined system of generator and uninterruptible power supply system) commonly used to deal with the load shedding problem. The results show that the renewable based hybrid system is a reliable and cost-effective option to address grid intermittency problem.
7
Sharov, I. M., O. A. Demin, A. A. Sudakov, and A. D. Yarlykov. "Development and research of uninterruptible power supply system for networks with supply voltage up to 24 V." Russian Technological Journal 10, no. 5 (October 21, 2022): 60–72. http://dx.doi.org/10.32362/2500-316x-2022-10-5-60-72.
Abstract:
Objectives. Due to the continuous rapid development of renewable energy sources, requirements for secondary power supply systems keep increasing from year to year. Productive uptime for end users is dependent on the efficiency and stability of the power supply system. Such systems should be able to distribute and store energy from renewable sources having various parameters and configurations. Therefore, the present work is aimed at developing technical solutions for efficient uninterruptible secondary power supply systems in low voltage DC networks.Methods. Advanced circuitry solutions are used for performing pulse conversions with high efficiency. The flexible hardware-software system is used for implementing the parameter control system.Results. An uninterruptible power supply for low-voltage DC networks is developed. The description of subsystems and calculations for all main elements including the power ones are given. Using a contemporary component base, the system prototype is assembled, configured, and measured by parameters. The presented solutions allow achieving the universality of the system in terms of the input and output voltage range. Support for the fast-charging Power Delivery protocol is integrated. As well as regulating the battery charging current and voltage, the Li+ battery charging controller permits changes in the number of chargeable cells. The monitoring and control unit monitors network parameters and controls the system automation. Using a microcontroller as the control device, it is possible to easily change control parameters by changing software settings. Dual redundancy of the module monitoring the built-in battery parameters is used to ensure the reliability and safety of system functioning. Support for the standardized I2C communication protocol with a separate power bus allows any necessary sensors to be connected for monitoring system parameters. External high-power devices controlled by a PWM signal may be added, if required. In the paper, the Li+ battery charging profile recommended by the manufacturer is provided.Conclusions. The designed system provides stable power supply to end users at a power consumption up to 40 W for at least 45 min. The automation demonstrates reliable operation.
8
Rispoli, Fabio, Michele Iannuzzi, Edoardo De Robertis, Ornella Piazza, Giuseppe Servillo, and Rosalba Tufano. "Warning! Fire in the ICU." Prehospital and Disaster Medicine 29, no. 3 (May 28, 2014): 339–40. http://dx.doi.org/10.1017/s1049023x1400048x.
Abstract:
AbstractAt 5:30 pm on December 17, 2010, shortly after a power failure, smoke filled the Intensive Care Unit (ICU) of Federico II University Hospital in Naples, Italy, triggering the hospital emergency alarm system. Immediately, staff began emergency procedures and alerted rescue teams. All patients were transferred without harm. The smoke caused pharyngeal and conjunctival irritation in some staff members. After a brief investigation, firefighters discovered the cause of the fire was a failure of the Uninterruptible Power Supply (UPS).RispoliF, IannuzziM, De RobertisE, PiazzaO, ServilloG, TufanoR. Warning! Fire in the ICU. Prehosp Disaster Med. 2014;29(3):1-2.
9
He, Guofeng, Shicheng Zheng, Yanfei Dong, Guojiao Li, and Wenjie Zhang. "Model Predictive Voltage Control of Uninterruptible Power Supply Based on Extended-State Observer." Energies 15, no. 15 (July 28, 2022): 5489. http://dx.doi.org/10.3390/en15155489.
Abstract:
Finite-set model predictive controls have been widely used in inverter control because of the flexible target control and no need of a modulation unit. However, the mismatching of prediction model parameters produces prediction errors, resulting in a significant decline in the performance of finite-set model predictive controls. Aiming at the problem of model parameter mismatch, an extended-state observer was proposed to accurately estimate the disturbance of the system in this paper, and the obtained disturbance value was added to a finite-set model predictive control controller to compensate for the prediction error and achieve parameter robustness. By constructing a prediction model of the inverter output voltage in αβ coordinates, all the possible output voltage values were predicted by using different voltage vectors and system measurement values. A set of voltage vectors that minimized the cost function was selected, and its corresponding switching state was applied to the inverter in the next sampling period to achieve control of the output voltage quality. Both the simulation and experimental results showed that the finite-set model predictive voltage control method based on the extended-state observer can estimate the total disturbance quickly and accurately, suppress the influence of capacitance parameter disturbance, and improve the control effect of an inverter.
10
Sen, Gorkem, Ali Boynuegri, Mehmet Uzunoglu, Ozan Erdinc, and João Catalão. "Design and Application of a Power Unit to Use Plug-In Electric Vehicles as an Uninterruptible Power Supply." Energies 9, no. 3 (March 7, 2016): 171. http://dx.doi.org/10.3390/en9030171.
11
Gasparjans, A., A. Terebkov, V. Priednieks, and R. Klaucans. "Spectral Analysis of Output Voltages and Currents as a Criterion for Technical Diagnostics of Synchronous Generators of Ship Diesel Engine." Latvian Journal of Physics and Technical Sciences 57, no. 4 (August 1, 2020): 12–23. http://dx.doi.org/10.2478/lpts-2020-0018.
Abstract:
AbstractDiesel generator sets (DGU) are very widely used in autonomous power supply systems. An example is marine power plants, diesel locomotives with electric power transmission, uninterruptible power supply units, etc. The power of ship DGUs reaches 2–6 or more MW in one unit. The number of units on ships can be different, but, as a rule, at least two. In this paper, we propose a method of monitoring the dynamic electromechanical system “diesel synchronous generator”. The method aims at using a synchronous generator machine as a multifunctional accurate and sensitive sensor for diagnostic parameters of the electromechanical system. The proposed method of technical diagnostics is based on continuous monitoring of non-uniformity of diesel torque, fluctuations in the instantaneous angular velocity and instantaneous angular acceleration of the diesel crankshaft. These data are the results of a spectral analysis of stator currents and voltages of a synchronous generator.
12
Bosak, Mykola, Oleksandr Hvozdetskyi, Bohdan Pitsyshyn, and Serhii Vdovychuk. "THE RESEARCH OF CIRCULATION WATER SUPPLY SYSTEM OF POWER UNIT OF THERMAL POWER PLANT WITH HELLER COOLING TOWER." Theory and Building Practice 2020, no. 2 (November 20, 2020): 1–9. http://dx.doi.org/10.23939/jtbp2020.02.001.
Abstract:
Analytical hydraulic researches of the circulating water cooling system of the power unit of a thermal power plant with Heller cooling tower have been performed. Analytical studies were performed on the basis of experimental data obtained during the start-up tests of the circulating water cooling system of the “Hrazdan-5” power unit with a capacity of 300 MW. Studies of the circulating water cooling system were carried out at an electric power of the power unit of 200 - 299 MW, with a thermal load of 320 - 396 Gcal/hr. By circulating pumps (CP), water mixed with condensate is fed to the cooling tower, from where it is returned through the turbine for spraying by nozzles in the turbine steam condenser. An attempt to increase the water supply to the condenser by increasing the size of the nozzles did not give the expected results. The amount of the water supply to the circulating pumping station depends on the pressure loss in the circulating water cooling system. The highest pressure losses are in hydro turbines (HT), which are part of the circulating pumping station. Therefore, by adjusting the load of the hydro turbine, with a decrease in water pressure losses, you can increase the water supply by circulating pumps to the condenser. Experimental data and theoretical dependences were used to calculate the changed hydraulic characteristics of the circulating water cooling system. As a result of reducing the pressure losses in the section of the hydro turbine from 1.04 to 0.15 kgf/cm2, the dictating point for the pressure of circulating pumping station will be the turbine steam condenser. The thermal power plant cooling tower is designed to service two power units. Activation of the peak cooler sectors of the cooling tower gives a reduction of the cooled water temperature by 2-4 °С only with the spraying system.
13
Özküçük, Serhat, and Songül Akbulut Özen. "Isolated solar electronic unit design including capacitive storage for the uninterruptible power supply of critical DC loads." Solar Energy 214 (January 2021): 367–76. http://dx.doi.org/10.1016/j.solener.2020.11.065.
14
Hasibuan, Arnawan, Muhammad Daud, Rizki Shobirin Hutagalung, Kartika Kartika, I. Made Ari Nrartha, and Rizky Almunadiansyah. "Battery charger regulator with fully controlled return 15 V/5 A in uninterruptible power supply." International Journal of Applied Power Engineering (IJAPE) 13, no. 1 (March 1, 2024): 45. http://dx.doi.org/10.11591/ijape.v13.i1.pp45-51.
Abstract:
Fully controlled rectifier and BCR. The battery charge regulator (BCR) is the most important unit of an uninterruptible power supply (UPS) device. The BCR uses a 15 V/5 A transformer to lower the voltage so as not to overload the BCR components. Full control using four thyristors serves to supply voltage to the BCR, while the BCR serves to regulate battery charging. Forcing the battery to be charged at a constant voltage with the same current results in shorter battery life. Battery charging through the BCR is set to match the battery voltage, then allowing the BCR to control it by adjusting the phase voltage to 13.5 V for high voltage discharge (HVD) and 10.5 V for low voltage discharge (LVD). By using an IC Regulator combined with a relay as a voltage breaker for a fully charged battery, it will automatically disconnect to avoid overcharging the battery. Based on the performance test results of a fully controlled rectifier system using thyristors and BCR on a 12V/5Ah battery, the output voltage is as a fully controlled 12 V rectifier, the BCR switch can charge the internal battery in minutes with a current that varies between 2.1 A to 0.1 A.
15
VALCHEV, Slav, and Ivan MIHAILOV. "Examination of Energy Efficiency of Air Handling Unit with Integrated Air to Air Heat Exchanger in Cooling Mode." Eurasia Proceedings of Science Technology Engineering and Mathematics 17 (September 16, 2022): 45–52. http://dx.doi.org/10.55549/epstem.1175946.
Abstract:
Object of the present study is an experimental determination of parameters, showing efficiency of air handling unit with integrated air to air heat exchanger in cooling mode: effectiveness of supply side of air to air heat exchanger, coefficient of performance and specific fan power of air handling unit. A daily performance of air handling unit in cooling mode is conducted. Effectiveness of supply side of air to air heat exchanger in range of 50.5 % to 74.3 % is received. Coefficient of performance in range of 0.88 to 2.99 and specific fan power of air handling unit in range of 1.77 kW/(m3/s) to 3.06 kW/(m3/s) are received. A relation between effectiveness of supply side of air to air heat exchanger and ratio of heat capacity rates of supply and exhaust air is received. Effectiveness of supply side of air to air heat exchanger depends on values of mass flow of supply and the exhaust air. High values of mass flow of exhaust air responds to high effectiveness of supply side of air to air heat exchanger.
16
Gu, Bonhyun, Heeyun Lee, Changbeom Kang, Donghwan Sung, Sanghoon Lee, Sunghyun Yun, Sung Kwan Park, Gu-Young Cho, Namwook Kim, and Suk Won Cha. "Receding Horizon Control of Cooling Systems for Large-Size Uninterruptible Power Supply Based on a Metal-Air Battery System." Energies 13, no. 7 (April 1, 2020): 1611. http://dx.doi.org/10.3390/en13071611.
Abstract:
As application of electric energy have expanded, the uninterruptible power supply (UPS) concept has attracted considerable attention, and new UPS technologies have been developed. Despite the extensive research on the batteries for UPS, conventional batteries are still being used in large-scale UPS systems. However, lead-acid batteries, which are currently widely adopted in UPS, require frequent maintenance and are relatively expensive as compared with some other kinds of batteries, like metal-air batteries. In previous work, we designed a novel metal-air battery, with low cost and easy maintenance for large-scale UPS applications. An extensive analysis was performed to apply our metal-air battery to the hybrid UPS model. In this study, we focus on including an optimal control system for high battery performance. We developed an algorithm based on receding horizon control (RHC) for each fan of the cooling system. The algorithm reflects the operation properties of the metal-air battery so that it can supply power for a long time. We solved RHC by applying dynamic programming (DP) for a corresponding time. Different variables, such as current density, oxygen concentration, and temperature, were considered for the application of DP. Additionally, a 1.5-dimensional DP, which is used for solving the RHC, was developed using the state variables with high sensitivity and considering the battery characteristics. Because there is no other control variable during operation, only one control variable, the fan flow, was used, and the state variables were divided by section rather than a point. Thus, we not only developed a sub-optimal control strategy for the UPS but also found that fan control can improve the performance of metal-air batteries. The sub-optimal control strategy showed stable and 6–10% of improvement in UPS operating time based on the simulation.
17
Hailu, Getu, Martin Henke, and Todd Petersen. "Stationary Battery Thermal Management: Analysis of Active Cooling Designs." Batteries 8, no. 3 (March 1, 2022): 23. http://dx.doi.org/10.3390/batteries8030023.
Abstract:
Stationary battery systems are becoming more prevalent around the world, with both the quantity and capacity of installations growing at the same time. Large battery installations and uninterruptible power supply can generate a significant amount of heat during operation; while this is widely understood, current thermal management methods have not kept up with the increase of stationary battery installations. Active cooling has long been the default approach of thermal management for stationary batteries; however, there is no academic research or comparative studies available for this technology. The present work presents assessment of different active cooling methods through an experimentally validated computational fluid dynamics simulation. Following model validation, several cooling system configurations were analyzed, including effects from implementing either a perforated vent plate or vortex generators. The vent plate was observed to greatly increase cooling performance while simultaneously promoting temperature uniformity between batteries. Vortex generators were shown to marginally increase cooling performance, yet, future research is recommended to study the effects and improvement of the design. The average battery temperature for the vented model is reduced by approximately 5.2 °C, while the average temperature differential among the batteries was only 2.7 °C, less than the recommend value (3 °C) by ASHRAE/IEEE Standards.
18
Ahmed, Toqeer, Faizan Ahmad Khan, Asad Waqar, Shakir Mehmood, Hamza Shakeel, Shahzad Hassan, Tausif Zahid, and Qasim Awais. "Design and Implementation of PV Fed Local UPS Inverter." Pakistan Journal of Engineering and Technology 4, no. 4 (December 16, 2021): 1–8. http://dx.doi.org/10.51846/vol4iss4pp1-8.
Abstract:
Locally manufactured Uninterruptible Power Supply (UPS) units are purchased as an alternative to rolling blackouts and load shedding in underdeveloped and developing countries like Pakistan. These locally manufactured UPS units are energy-inefficient, causing stress on the national grid and cost-intensive for the residential consumer in the form of high utility bills of electricity. In this regard, the authors have proposed the PV fed local UPS inverter to make the existing UPS unit more efficient through photovoltaic (PV) energy without disrupting its function of providing uninterrupted supply during load-shedding hours. In order to validate the performance of the proposed PV fed local UPS inverter, the maximum power point tracking (MPPT) PV charge controller module is designed and implemented practically in a hardware setup and simulated in MATLAB/Simulink and Proteus environment, respectively. Moreover, the installation of an MPPT PV charge controller module in an existing locally manufactured UPS unit is also discussed. The practical results demonstrate the superiority of the proposed PV fed local UPS inverter with an average efficiency of 81.51% and a lowest total harmonic distortion (THD) of 1.29% as compared to existing UPS inverters.
19
Ignatkin, Ivan, Sergey Kazantsev, Nikolay Shevkun, Dmitry Skorokhodov, Nikita Serov, Aleksei Alipichev, and Vladimir Panchenko. "Developing and Testing the Air Cooling System of a Combined Climate Control Unit Used in Pig Farming." Agriculture 13, no. 2 (January 30, 2023): 334. http://dx.doi.org/10.3390/agriculture13020334.
Abstract:
This article presents the results of developing and testing the air-cooling system of a combined climate control unit used in pig farming. The authors have found a water-evaporative system to be the most efficient for cooling the air supply. Cooling systems of this type consume 0.003 kW/kW of electric power to produce 1 kW of cold. Based on the developed mathematical model for water-evaporative cooling in the combined climate control unit, the authors have determined that an air supply with a temperature of 31.2 °C and a relative humidity of 30.4% can be cooled by 8.3 °C when saturated with moisture to a relative humidity of 90.0% (by 11.7 °C at 100%). Experimental studies of the cooling system confirmed the theoretically obtained data.
20
Meng, Jianbing, Tingrong Wang, Guanghua Li, and Jianhong Kang. "Simulation Test on Cooling and Fire Suppression with Liquid Nitrogen in Computer Room of Data Center." Fire 6, no. 3 (March 13, 2023): 116. http://dx.doi.org/10.3390/fire6030116.
Abstract:
With the rapid development of worldwide computer data center construction, the reliability requirements of the fire-fighting system for data center rooms are also increasing. By using the self-designed simulation platform of liquid nitrogen spray, this paper studies the liquid nitrogen cooling process in the initial heating stage of a computer data center room fire and the liquid nitrogen extinguishing effects for common combustible materials, revealing the feasibility of applying liquid nitrogen to the fire extinguishing system for data center room. The results show that the cooling and inerting effects with quarter sector fan-shaped 6520 spray nozzle are the best among seven types of spray nozzles, the relative temperature changes by more than 50% within 5 min, and the oxygen concentration in the test space drops below 10%. Compared with optical fiber, the ignition range of uninterruptible power supply com-bination during combustion is relatively small. Liquid nitrogen has a significant fire-extinguishing effect on two combustible materials, which can successfully extinguish optical fiber and UPS within 3 min and 2 min, respectively.
21
S, Ganesh, Chiranjit Ghosh T, Kokilasree R, Nandhakumar M, and Md Haroon Alim T. "DC UPS for Critical Loads." International Journal of Electrical and Computer Engineering (IJECE) 5, no. 2 (April 1, 2015): 231. http://dx.doi.org/10.11591/ijece.v5i2.pp231-242.
Abstract:
<p>The usual way to avoid a computer shutdown during a mains failure is to connect an uninterruptible power supply system (UPS), which can be suitably modified and fitted inside the computer cabinet by the use of proposed methodology known as a dc UPS. Conventional desk top UPS systems store electricity in form of chemical energy in batteries and when ever mains fail the batteries provide DC power which is then converter to ac by inverter and then fed to the computer in order to save critical data. Thus power from mains or from UPS is fed to switched mode power supply unit which converts it to dc to supply the computer motherboard and accessories. Leaving the case of the computer powered by mains, duing power failure the dc power is unnecessarily converted to ac and then to dc again in SMPS hence high switching losses and heat is produced there by making the entire system very lowe efficient. In this work it is proposed to directly feed the dc power from the battery to the computer SMPS system by building a UPS arrangement within the computer system. This not noly saves space, it is highly efficient compared to the conventional ups system, easy to carry, low cost and reliable since there is no change over operation is required/. A complete design of an ac to dc power supply with an internal dc UPS is presented in this paper. . A prototype has been fully developed and tested as a PC power supply. Thus the result is achieved at full power about 6-8 minutes.</p>
22
Kim, Ki-Du, Young-Soo Kim, Han-Goo Kim, and Ji-Su Ryu. "Research on the Development of 1500㎸A High-Efficiency/Unit Module Offline Uninterruptible Power Supply Applied to Semiconductor Manufacturing Equipment." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 37, no. 6 (November 30, 2023): 34–42. http://dx.doi.org/10.5207/jieie.2023.37.6.034.
23
Bedrin, Alexander G., Alexander P. Guryev, Valentin M. Gromovenko, and Galina A. Sokolova. "Forcing Power Supply of a Xenon Flash Lamp to Create a High Power Irradiation Facility." Light & Engineering, no. 04-2022 (August 2022): 56–62. http://dx.doi.org/10.33383/2021-118.
Abstract:
The article describes the technical characteristics of the software-controlled power supply system for generation of second-long light pulses by means of INP‑16/580 xenon flash lamps. The amplitude-time characteristics of luminous emission in a quasi-arc mode of lamp operation are formed by computer control of temporal current pulse shape in case of large energy deposition overloads. Methods of optimisation of light and engineering characteristics were defined accounting for non-linearity of the load of the thyristor unit and ambiguity of the dependence of luminous radiation on discharge current. The data on maximum acceptable operation parameters of pulse lamps with mains supply and natural air cooling and the results of physical modelling of radiation pulses with complex shape are presented.
24
Supriyadi, Edy, Muhammad Febriansyah, and Suekowani Suekowani. "ANALISA PENGARUH SUHU PADA LOW VOLTAGE POWER SUPPLY PS2 DI CDU (CONTROL DISPLAY UNIT)." SINUSOIDA 25, no. 2 (December 2, 2023): 20–29. http://dx.doi.org/10.37277/s.v25i2.1924.
Abstract:
Low Voltage Power Supply PS2 ( LVPS ), adalah jenis power supply switching yang sangat penting, karena semua daya yang dibutuhkan untuk bekerjanya CDU B737 – Klasik ( Control Display Unit ) diperoleh dari power ini.CDU B737- Klasik adalah komponen yang berfungsi sebagai media interaksi antara operator ( teknisi atau pilot ) dengan pesawatnya. Dari banyaknya CDU yang diturunkan dari pesawat ( unserviceable ), dengan reason of removal display CDU sometimes blank, pengaruh dominan penyebabnya adalah disebabkan oleh faktor LVPS. Dalam Penelitian ini telah dilakukan pengujian dan analisa untuk menghindari terjadinya alasan CDU sometimes blank, yang ternyata diakibatkan oleh over heating di dalam casing LVPS akibat dari Foreign Object Damage ( FOD ), membuat CDU tidak berfungsi yang berakibat pesawat menjadi terdegradasi ( fail safe). Berdasarkan analisa, Over heating ini diakibatkan oleh FOD yang menghambat sirkulasi udara di dalam LVPS. Untuk itu diharapkan kepada unit yang berwenang dalam hal ini Engineering lebih intensif lagi menjalankan procedure maintenance pada pesawat Boeing 737 klasik, terutama untuk penggantian filter pada system cooling di komponen Avionik tempat dimana CDU terpasang.
Kata kunci: Control Display Unit, Low Voltage Power Supply.
25
Ishizuka, M. "The effects of the outlet area and the location of the main power supply unit on the cooling capability through naturally air-cooled electronic equipment casings." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, no. 5 (August 1, 1998): 381–83. http://dx.doi.org/10.1243/0957650981536943.
Abstract:
This paper describes a practical thermal design approach to natural air-cooled electronic equipment casings. A set of simplified equations for the thermal design of natural air-cooled electronic equipment casings has been proposed. The proposed set of equations satisfied the demand of practical air-cooling systems, since it takes account of factors such as the stack effect, the air flow resistance and the heat transfer due to natural convection. The effects of the outlet area and the location of the main power supply unit on the natural cooling capability of electronic equipment casings were studied using a set of equations. The results have shown that a uniform temperature distribution could be achieved when the main power supply unit was placed at the bottom of the casing. It has also been suggested that the value of the heat removed from the casing surface could be more significant than that from the outlet vent in the thermal design of natural air-cooled electronic equipment casings.
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Sen, Ozan, and Ceyhun Yilmaz. "Thermoeconomic Cost Analysis of Solar and Geothermal Energy Powered Cooling and Power Cogeneration." Academic Perspective Procedia 3, no. 1 (October 25, 2020): 609–18. http://dx.doi.org/10.33793/acperpro.03.01.114.
Abstract:
In this study, geothermal and solar energy assisted cogeneration energy system has been modeled to supply residences' electricity and cooling requirements. The geothermal water from the geothermal resource and the heat transfer fluid heated in the parabolic collector is used as the heat source in the absorption cooling system. Electricity is generated in the binary power plant with geothermal water and heat transfer fluid from the absorption cooling system. The generated electricity is supplied to the grid. Thermoeconomic analysis of the system is performed by using the Engineering Equation Solver (EES) program by using geothermal and solar energy values of Afyonkarahisar. The geothermal resource's temperature and mass flow in the system is 130 &ordm;C and 85 kg/s, respectively. The parabolic trough collector operates in the range of monthly average solar radiation values (500-600 W/m2) calculated for the summer season, where cooling is planned. The LiBr-H2O solution is chosen as the refrigerant of the absorption cooling system. The system's parametric study is performed by considering the different geothermal resource temperatures and solar radiation values. According to these results, the unit electricity and unit cooling costs produced in the system will be investigated. The optimum working conditions are investigated in producing and using the energy form (electricity-cooling) requirements.
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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.
Abstract:
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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Wang, Yubo, Ling Hao, Libin Zheng, Lei Chen, Fei Xu, Qun Chen, and Yong Min. "Low-Carbon Economic Dispatch of Electricity and Cooling Energy System." Processes 11, no. 9 (September 18, 2023): 2787. http://dx.doi.org/10.3390/pr11092787.
Abstract:
In response to the issue of the hydropower consumption of run-of-river hydropower stations in Southwest China, the district cooling system can provide regulation capacity for hydropower utilization and suppress fluctuations caused by the uncertainty of hydropower. The innovative method is to utilize the thermal characteristics of pipelines and buildings, as well as the thermal comfort elasticity to shift the cooling and electricity loads, which helps to consume the surplus hydroelectric power generation. Taking the minimum total cost of coal consumption in thermal power units, hydropower abandonment penalty, and the carbon trading cost as the objective function, models were established for power supply balance constraints, heat transport constraints, and unit output constraints. The hybrid integer linear programming algorithm was used to achieve the low-carbon economic dispatch of the electric-cooling system. The calculation examples indicate that compared to the traditional real-time balance of cooling supply, the comprehensive consideration of thermal characteristics in a cooling system and flexible thermal comfort have a better operational performance. The carbon trading cost, coal consumption cost, and abandoned hydropower rate of a typical day was reduced by 4.25% (approximately CNY 7.55 × 104), 4.47% (approximately CNY 22.23 × 104), and 3.66%, respectively. Therefore, the electric-cooling dispatch model considering the thermal characteristics in cooling networks, building thermal inertia, and thermal comfort elasticity is more conducive to the hydropower utilization of run-of-river stations.
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Hviid, Christian A., Daria Zukowska-Tejsen, and Vilhjalmur Nielsen. "Cooling of schools – results from a demonstration project using adiabatic evaporative cooling with harvested rainwater." E3S Web of Conferences 172 (2020): 02003. http://dx.doi.org/10.1051/e3sconf/202017202003.
Abstract:
This paper reports on a demonstration project where a section of a school building with eight classrooms and three other rooms was retrofitted with a mechanical balanced ventilation system with an integrated evaporative cooling unit. The floor area was 537 m2. Especially in temperate climates, evaporative cooling has unreleased potential as an alternative solution to conventional cooling technologies, and by combining it with harvesting of rainwater, the solution aligns well with a future with higher cooling needs, need for climate adaptation, and the overall sustainability agenda. The cooling unit works by storing, filtering and spraying rainwater into the return air. The water evaporates, cools the return air, and through an innovative corrosion-resilient plastic heat exchanger, the return air then absorbs heat from the supply air. In this way indoor climate problems caused by humidification of the indoor air are avoided. The demonstration was running in the May and June 2019. The results show that the specific fan power increased approx. 500 J/m3 when the evaporative cooling pumps were activated and that the available cooling power – depending on the moisture content of the return air – was fluctuating in the range 20-30 W/m2. The peak rainwater consumption was approx. 1 m3/day. The results show that implementation of evaporative cooling with harvested rainwater is an attractive and sustainable alternative to mechanical compressor cooling.
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Yan, Xiaopeng, and Baijin Chen. "Energy-Efficiency Improvement and Processing Performance Optimization of Forging Hydraulic Presses Based on an Energy-Saving Buffer System." Applied Sciences 10, no. 17 (August 31, 2020): 6020. http://dx.doi.org/10.3390/app10176020.
Abstract:
This paper proposes an energy-saving system based on a prefill system and a buffer system to improve the energy efficiency and the processing performance of hydraulic presses. Saving energy by integrating such systems into the cooling system of a hydraulic press has not been previously reported. A prefill system, powered by the power unit of the cooling system, is used to supply power simultaneously with the traditional power unit during the pressurization stage, thus reducing the usage of pumps and installed power of the hydraulic press. In contrast to the traditional prefill system, the proposed energy-saving system is controlled by a servo valve to adjust flow according to the load profile. In addition, a buffer system is employed to the cooling system to absorb the hydraulic shock generated at the unloading stage, store those shares of hydraulic energy as a recovery accumulator, and then release this energy to power the prefill system and the hydraulic actuator in the subsequent productive process. Finally, through a series of comparative experiments, it was preliminarily validated that the proposed system could reduce the installed power and pressure shock by up to 22.85% and 41%, respectively, increase energy efficiency by up to 26.71%, and provide the same processing characteristics and properties as the traditional hydraulic press.
31
Wang, Zhonghao, Wei Lin, Wei Wang, Zhangwei Wang, Jimin Li, Jianmin Xu, and Jiuyang Yu. "Research on performance optimization and mechanism of electrochemical water softening applied by pulse power supply." Water Science and Technology 84, no. 9 (October 4, 2021): 2432–45. http://dx.doi.org/10.2166/wst.2021.436.
Abstract:
Abstract In order to promote the application of electrochemical water softening technology in industrial circulating cooling water systems, electric field type, cathode structure and solution residence time are selected for optimization analysis of an electrochemical water softening device. The experimental results show that the water softening performance per unit area of mesh cathode is better than that of a plate cathode. In addition, the softening amount per unit area of the mesh cathode can be further increased when the high-frequency (HF) power supply is applied. When the HF power supply is applied, the softening amount per unit area is 158.58 g/m2·h−1 more than when the direct current power supply is applied. In order to explore the growth mechanism of calcium carbonate, micro-analysis technology and high-speed bubble photography technology are used. The results show that the bubbles escape along the longitudinal direction of the electrode plate, and the main growth direction of calcium carbonate growth is consistent with the escape direction of the bubble; that is, the bubbles grow along the longitudinal direction of the electrode plate. The special structure of the diamond-shaped mesh cathode facilitates the growth of calcium carbonate crystals.
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Guo and Ye. "Numerical and Experimental Study on a High-Power Cold Achieving Process of a Coil-Plate Ice-Storage System." Energies 12, no. 21 (October 25, 2019): 4085. http://dx.doi.org/10.3390/en12214085.
Abstract:
Heat dissipation of high-power lasers needs a cold storage and supply system to provide sufficient cooling power. A compact coil-plate heat exchange device has been proposed and applied in the phase-change cold storage system with ice as the cold-storage medium and glycol aqueous solution as the coolant. The heat exchanger consists of several stacked coil-plate units and each unit is constructed with a flat plate and serpentine coils welded on the plate. A simulation model on the cold achieving process of a coil-plate unit was built and verified by the corresponding experiment. The influences of the structural parameters (tube diameter, tube pitch, and plate spacing) of the unit and the inlet temperature and volume flow rate of the coolant on the heat exchange power density were analyzed to obtain the maximal cooling effect in a limited time period. It was found that the heat exchange power density is limited when the tube pitch and plate spacing are large, otherwise, the effective cooling time period is limited. A small plate spacing can make the power density decrease rapidly in the later stage. The inlet coolant temperature can significantly affect the heat exchange power density while the coolant volume flow rate in tube has a small effect on the power density when the coolant is in turbulent state. In a time period of 900 s, for a coil-plate heat exchanger with a plate size of 940 mm ×770 mm and a tube pitch of 78 mm, when the plate spacing is 20 mm, the average heat exchange power density is 5.1 kW/m2 when the inlet temperature and volume flow rate of the coolant are 20 °C and 0.5 m3/h, respectively. The total cooling power of several stacked coil-plate units in the limited time period can match the high requirement of laser heat dissipation.
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Borush, O. V., O. K. Grigoryeva, and A. A. Frantseva. "Thermal and aerodynamic characteristics of air cooled condenserfor steam turbine power unit." Power engineering: research, equipment, technology 26, no. 1 (April 24, 2024): 93–106. http://dx.doi.org/10.30724/1998-9903-2024-26-1-93-106.
Abstract:
THE PURPOSE. Increased water consumption at power plants leads to a deterioration of the environmental situation not only in countries with limited water supply sources, but also in countries with significant reserves of fresh water. There is a need to consider the possibility of using an air condenser as an alternative use in industrial water supply systems at a power plant. To present a methodology for calculating the main characteristics of a condenser (condensation and reflux sections), to estimate the aerodynamic resistance and fan power for an air-cooled condenser as part of a steam turbine power unit. Determine the influence of air temperature and pressure in the condenser on the calculation of the air condenser. To develop recommendations for the selection of parameters of air condensers operating as part of steam turbine power units. METHODS. Methods for designing heat exchangers, modeling and intensifying heat exchange processes were used in the course of calculating an air condenser unit. RESULTS. A method for calculating an air-cooled condenser for a 110 MW condensing turbine has been developed. The analysis of the calculation of the heat transfer coefficient is given. The analysis of the values of the heat exchange area of the condensing unit is presented. The effect of pressure in the condenser on the main calculated characteristics of the condenser is shown. Recommendations for the selection of the fan capacity in the condenser and the design temperature of the cooling air have been developed. CONCLUSION. The issue of using air coolers in the power industry is still poorly covered in the literature, however, environmental problems and the shortage of fresh water are becoming more and more urgent all over the world. The development of air-cooling systems is a very topical issue for modern power engineering. It is shown that for stationary installations of condensation of water vapor, the most suitable is the hipped-roof arrangement of the heat-exchange sections with the lower arrangement of the fans. Quantitative estimates of the change in the heat transfer coefficient and the area of the heat-exchange surface are given for the pressure range of 8…20 kPa. The power consumption of the fan depends significantly on the temperature of the cooling air and the vacuum in the condenser.
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Dronov, Dmitry M., Aleksandr V. Gontovoy, Yelena N. Sarkisyan, and Natalya V. Karandeeva. "Experience of using the NALCO 1392 scale inhibitor in the circulating water supply system of the Novovoronezh NPP." Nuclear Energy and Technology 7, no. 2 (June 21, 2021): 85–89. http://dx.doi.org/10.3897/nucet.7.68940.
Abstract:
Power facilities use large amounts of water to cool steam in the steam turbine condensers, and lubricating oils, gas and air in turbine sets. The key requirement for the quality of cooling water is to ensure normal vacuum in condensers. Cooling water must not form mineral and biological deposits and corrosion products in the system. Deposits of mineral salts in the condenser tube system, as well as in auxiliary cooling systems, lead to deterioration in heat exchange and a major decrease in the cost effectiveness of the power equipment operation, and require the heat-exchange equipment to be periodically cleaned. The source water used for cooling is normally taken from nearby water bodies (large rivers or lakes). Circulating water supply systems are used most commonly: these systems use repeatedly the same water inventory for cooling, and require only small amounts of water added to make up for evaporation losses. Coolers, in this case, are cooling towers, spray pools and evaporation ponds. The water chemistry should ensure the operation of equipment without any damage to its components or the loss of efficiency caused by the corrosion of the internal surfaces as well as without scale and sludge formation. It is exactly when using circulating water supply that a stabilizing treatment program is the most practicable way to ensure a cost-effective and environmentally friendly mode of operation. To inhibit scaling processes on the heat-exchange surfaces of the turbine condenser tubes at the Novovoronezh NPP’s unit 5, the cooling water was treated with the NALCO 1392 inhibitor. The results of the NALCO 1392 inhibitor pilot tests in the circulating water supply system (with a cooling pool) are presented.
35
Rogalev, Nikolay, Daria Kharlamova, Andrey Vegera, Vladimir Naumov, and Timofey Karev. "Research and Development of Hybrid Power Units Heat Flow Diagrams with Cooled High-Temperature Steam Turbines." Inventions 7, no. 3 (July 27, 2022): 64. http://dx.doi.org/10.3390/inventions7030064.
Abstract:
Fossil fuel thermal power plants account for almost 60% of Russian electricity and heat. Steam turbine units make almost 80% of this amount. The main method for steam turbine unit efficiency improvement is the increase in the initial steam parameters’ temperature and pressure. This reduces fossil fuel consumption and harmful emissions but requires the application of heat-resistant steel. The improvement in steel’s heat resistance leads to a non-linear price increase, and the larger the temperature increase, the more the steel costs. One of the methods of improving efficiency without a significant increase in the capital cost of equipment is an external combustion chamber. These allow an increase in the steam temperature outside the boiler without the need to use heat-resistant alloys for boiler superheaters and steam pipelines between the boiler and the steam turbine. The most promising is hydrogen–oxygen combustion chambers, which produce steam with high purity and parameters. To reduce the cost of high-temperature steam turbines, it is possible to use a cooling system with the supply of a steam coolant to the most thermally stressed elements. According to the calculations, the efficiency reduction of a power unit due to the turbine cooling is 0.6–1.27%. The steam superheating up to 720 °C in external combustion chambers instead of a boiler unit improves the unit efficiency by 0.27%. At the initial steam temperatures of 800 °C, 850 °C, and 900 °C, the unit efficiency reduction caused by cooling is 4.09–5.68%, 7.47–9.73%, and 8.28–10.04%, respectively.
36
Zaykov, Vladimir P., Vladimir I. Mescheryakov, and Yurii I. Zhuravlov. "Control of a thermoelectric cooling unit complex mixed electrical connection in an uneven temperature field." Herald of Advanced Information Technology 5, no. 4 (December 28, 2022): 309–24. http://dx.doi.org/10.15276/hait.05.2022.23.
Abstract:
A possibility of optimal thermal management of a number of temperature-dependent and heat-laden elements of radio electronic equipment with different power dissipation in an uneven temperature field using a set of thermoelectric cooling devices with mixed electrical connection and fixed geometry of thermocouple branches has been considered. Ratios for determining the relative operating current corresponding to the minimum supply voltage at a given thermal load for different temperature gradients and thermocouple branch geometries are derived. The possibility of selecting a supply voltage for a group of thermoelectric coolers with parallel electric connection using both analytical and graphical methods of solving a system of algebraic equations of first and second orders is shown. The basic parameters, reliability indices and dynamic characteristics of a thermoelectric cooler complex with mixed electrical connection when a group of thermoelectric coolers with series electrical connection operates at maximum cooling capacity and supply voltage variation of a group of coolers with parallel electrical connection are evaluated. Analysis of the research results showed the possibility of selecting the optimum supply voltage for a group of thermoelectric coolers with parallel electric connection in the interrelation of energy, mass-dimensional and dynamic characteristics, taking into account the reliability indicators of the complex as a whole. It is shown that by reducing the supply voltage of a group of thermoelectric coolers with parallel electric connection included in the complex, the energy, mass-size and dynamic characteristics are improved, and the reliability of the complex with mixed electric connection in an uneven temperature field is increased.
37
Haili, Chang. "Energy-saving design and implementation in metro weak current systems: a case study of the Kunming metro system." Urban Rail Transit 7, no. 4 (December 2021): 301–33. http://dx.doi.org/10.1007/s40864-021-00158-3.
Abstract:
AbstractWith the accelerated urbanization in China, along with the growing scale of the metro transportation network, the energy consumption of metro systems continues to increase. To face the tough challenge of climate change, China has put forward the goal of peak carbon emissions by 2030 and achieving carbon neutrality by 2060. Energy consumption has become a serious burden for metro operation companies, since 10.2% of the total operational budgets is spent on electricity. Thus the development of methods to realize energy saving and emission reduction has become a major challenge for metros. In this study we conduct an in-depth research and analysis on metro energy load classification and energy management, focusing in particular on the design and usage of power supply systems for metro weak current electromechanical systems, including tunnel fans, station air conditioners, station escalators, automatic ticketing equipment, screen doors, drainage pumps, sewage pumps, platform doors, communication systems, signals, integrated monitoring systems, automatic ticketing and various lighting equipment and facilities. It is proposed that the five weak current systems, namely platform doors, communication systems, signals, integrated monitoring and automatic fare collection, should adopt a backup power supply. In order to ensure the reliable operation of all weak current systems in the station, the traditional decentralized power supply mode is changed to a centralized power supply and uninterruptible power supply (UPS) (1 + 1) parallel double-bus system. At the same time, combined with the data on equipment quantity, station passenger flow and station building floorage, the Boruta algorithm is used to filter out the equipment related to station weak current energy consumption, and a principal component analysis (PCA) algorithm is used to further reduce the dimensions of the filtered features to reduce the algorithm overhead of the subsequent quota analysis model. The XGBoost algorithm is used to establish a prediction model for station weak current system energy consumption. Analysis shows that there is a strong correlation between the energy consumption quota and the equipment quantity as well as station building floorage. By setting different metering instruments for power supply circuits, the main energy consumption data are collected to meet the requirements for graded metering of metro energy consumption, and then the energy consumption quota for the station weak current system is reasonably predicted. By adding metering instruments to the power supply circuits of different areas and equipment, the energy consumption of the weak current system can be measured and monitored in different grades. The combination of the energy management platform and energy consumption quota provides the basis for energy management of each energy-consuming unit, and ultimately realizes energy saving and reduced consumption.
38
Takahashi, Keisuke, Itsuki Miyazato, Satoshi Maeda, and Lauren Takahashi. "Designing transformer oil immersion cooling servers for machine learning and first principle calculations." PLOS ONE 17, no. 5 (May 17, 2022): e0266880. http://dx.doi.org/10.1371/journal.pone.0266880.
Abstract:
A transfomer oil immersion cooling server is designed and constructed for machine learning applications and first principle calculations that are carried out for materials-related research. CPU, motherboard, random access memory, hard disk drive, solid state drive, graphic card, and the power supply unit are submerged into the transformer oil in order to cool the entire system. Benchmark tests reveal that overall performance is improved while performance times for multicore calculations are dramatically improved. Furthermore, calculation times for machine learning with large data sets and density functional theory calculations are shortened during single core calculations. Thus, a transformer oil immersion cooling server is proposed to be an alternative cooling system used for improving the performance of first principle calculations and machine learning.
39
Balzamov, D., I. Akhmetova, and E. Balzamova. "Options for Modernization of Heat Supply to Consumers of Condensing Power Plant." Energy Systems Research, no. 2(14) (July 23, 2021): 35–45. http://dx.doi.org/10.38028/esr.2021.02.0004.
Abstract:
High competition and strict requirements of the wholesale electricity and capacity market make optimization of heat supply schemes an urgent issue for generating companies. Replacement of life-expired generation equipment with new capacities based on advanced technologies is a priority goal for the energy industry development. This work focuses on condensing power plant (CPP), which is the only source in the city that supplies heat to all consumer categories. The plant carries out quantitative and qualitative heat supply regulation according to the temperature profile of 135/70°C with a cutoff of 110/70°C. The study examines the possibility of CPP modernization based on three options: building a pressure-reducing cooling unit 140/12, commissioning an auxiliary boiler house, and building a 110 MW combined-cycle gas plant. This paper presents technical solutions for the considered options and preliminary technical and economic calculations of their efficiency.
40
Amorim, Marcio L. M., Gabriel Augusto Ginja, João Paulo Carmo, Melkzedekue Moraes Alcântara Moreira, Adriano Almeida Goncalves Siqueira, and Jose A. Afonso. "Low-Cost/High-Precision Smart Power Supply for Data Loggers." Energies 16, no. 1 (December 27, 2022): 278. http://dx.doi.org/10.3390/en16010278.
Abstract:
This paper presents a low-cost/high-precision smart power supply for application on data loggers. The microprocessor unit is the brain of the system and manages the events and was optimized to provide electrical energy to the electronic devices under normal operation and under the presence of disruptive events. The measurements showed that when switching either from battery to AC or from AC to battery, neither caused the shutdown of the power supply nor affected the behavior of the power supply. The power supply was able to charge 80% of the battery on a fast recharge of 1 h and the remaining 20% on a slow recharge of 2 h. The current allocated to the battery did not affect the operation of the power supply. The tests also showed that the power supply was able to transmit relevant information about its operation to external computers through a serial connection. This information includes the voltages at the battery and at the output of the voltage regulators, the voltage level of the AC network, the level of the battery charge and if it was being recharged, the current being drained, the internal temperatures at two locations (one measured on the resistor that limits battery charge and another measured on the output diode of the regulators), and whether the cooling system is being used. The total cost of this smart power supply is less than $150, demonstrating good potential for its popularization.
41
Huang, Congxin, and Zhiyang Wang. "Research and Application of Evaporative Cooling Ventilation and Salty Moisture Corrosion Prevention Technology for Steam Turbine House." E3S Web of Conferences 356 (2022): 01032. http://dx.doi.org/10.1051/e3sconf/202235601032.
Abstract:
This paper focus on Pakistan Hub coal-fired 2×660MW power project which located in the coast areas with high temperature and high salty moisture. The category of corrosivity of atmosphere in Pakistan Hub is C5. The high salty moisture will increase the corrosion of indoor equipment and structures in turbine house, which threaten the safe and stable operation of power plant. Direct evaporative cooling (DEC) technology is used to cool the centralized supply air for the turbine building. To prevent the salty moisture air being supplied into turbine building causes corrosion for indoor equipment and structures, the desalting moisture filter has been developed and combined with the evaporating cooling unit, which realized the large-scale engineering application. The efficiency of desalting moisture filter reaches more than 93% tested in Tongji University and VTT in Finland, under the condition of the design outdoor temperature of 38.9 °C in Karachi, the supply air temperature is 24.4 °C, which ensures the operating environments of working area and meeting the occupational hygiene requirements and anti-salt spray corrosion requirements.
42
Wang, Yongli, Xin Chen, Lisha Fan, Minhan Zhou, Huanran Dong, Kunpeng Zhao, and Shaokun Jia. "Operation optimization of multi-energy flow integrated energy system based on multi-objective." E3S Web of Conferences 213 (2020): 02022. http://dx.doi.org/10.1051/e3sconf/202021302022.
Abstract:
In order to solve the problem that most of the existing combined cooling, heating and power integrated energy systems only consider the investment cost of the system unit or the system environmental pollution affecting the overall optimization of the system, with the goal of system economy and environmental protection, the construction of gas turbines, gas boilers, The optimization model of the combined cooling, heating and power system of electric refrigerators and other units and the establishment of constraint conditions; according to the requirements of the cooling, heating, and electric loads in the dispatch cycle, as well as the energy supply efficiency of each equipment of the system, the starting and stopping power and other operating parameters are in the interval. Based on the respective data, a multi-energy flow regional integrated energy system economic dispatch optimization operation strategy optimized within the dispatch period is proposed. The results show that the operation strategy can take into account the economy and environmental protection of the system at the same time, make the system operation more optimized.
43
Zhao, Weixin, Simo Kilpeläinen, Risto Kosonen, and Juha Jokisalo. "Experimental comparison of local low velocity unit combined with radiant panel and diffuse ceiling ventilation systems." Indoor and Built Environment 29, no. 6 (May 4, 2020): 895–914. http://dx.doi.org/10.1177/1420326x20918398.
Abstract:
In this study, the performance of a micro-environment system was analysed and compared with diffused ceiling ventilation. In the analysed micro-environment low velocity radiant panel system, two low velocity units and radiant panels were installed above workstations to supply directly clean air to occupants and to cover the cooling power required. With diffused ceiling ventilation, all cooling demand is covered with air and thus, the airflow rate required is higher than with low velocity radiant panel system. The varied heat gain from 40 to 80 W/m2 consists of two seated dummies, laptops, monitors and simulated solar gain. The results show that with perimeter exhaust and local supply air, 8–13% reduction of the total cooling load required is possible, in comparison to the standard mixing systems. The average exhaust temperature was 0.7–1.9°C higher than average room air temperature at the workstation. Moreover, the mean air temperature with the low velocity radiant panel system at the occupied zone was 0.6°C lower than with diffused ceiling ventilation. With low velocity radiant panel system, the air velocity was less than 0.12 m/s in the occupied zone. Also, the draught rate was less than 10%. Furthermore, the air change efficiency with the low velocity radiant panel system was over 70% which is better than 44–49% efficiency with diffused ceiling ventilation.
44
Nassif, Nabil, and Iffat Ridwana. "Improving Building Energy Performance Using Dual VAV Configuration Integrated with Dedicated Outdoor Air System." Buildings 11, no. 10 (October 12, 2021): 466. http://dx.doi.org/10.3390/buildings11100466.
Abstract:
As building systems account for almost half of the total energy consumed by the building sector to provide space heating, cooling, and ventilation, efficiently designing these systems can be the key to energy conservation in buildings. Dual VAV systems with an effective control strategy can substantially reduce the energy consumption in buildings, providing a significant scope of further research on this system configuration. This paper proposes to utilize the warm air duct of the dual VAV system as a dedicated outdoor air (DOA) unit when no heating is required, which allows the cooling load to be effectively distributed between two ducts. A specific control sequence is proposed with different supply air temperature reset strategies to estimate the heating, cooling loads, and fan power energy consumption of the proposed system. A simple two-zone office building is taken as a preliminary case study to simulate the airflow rates and fan power of a single duct VAV and proposed dual VAV systems to illustrate the concept. Finally, a larger multi-zone office building is simulated to measure the annual heating, cooling loads, and fan power energy and compare the energy savings among the systems. The results show significant fan power reduction ranging from 1.7 to 9% and notable heating energy reduction up to 76.5% with a small amount of cooling load reduction varying from 0.76 to 2.56% depending on the different locations for the proposed dual VAV systems. Further energy savings from different supply air temperature reset strategies demonstrate the opportunity of employing them according to climates and case studies. The proposed dual VAV system proves to have the potential to be adapted in buildings for the purpose of sustainability and energy savings.
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Alimonti, Claudio, and Gabriele Pecci. "Back Analysis of a Horizontal Geothermal Plant Implemented in a Wine Production Process." Sustainability 14, no. 1 (December 24, 2021): 157. http://dx.doi.org/10.3390/su14010157.
Abstract:
The Salcheto winery has undertaken a process of reduction of its primary energy consumption and the implementation of green energy technologies. They adopted solar photovoltaic, wood biomass, and geothermal energy sources. A horizontal ground source heat exchanger (GSHE) plant is used to cool a part of the pressed grapes and control the wine production temperature. The goal of this work was to investigate some technical issues of the plant and to increase the efficiency of the whole system. The first step was the evaluation of the actual operating conditions of the GSHE plant, by performing a thermal response test. The results allowed us to find the thermal diffusivity of 3.5 × 10−7 m2/s, and the calculation with the IGSHPA standard indicated a cooling performance of about 6 kW. A survey during the harvest highlighted a peak power of 6 kW. Therefore, to improve the plant, some modifications were proposed and analyzed. In the new layout, the geothermal plant serves the condenser of the refrigeration unit, allowing cooling of the all production lines, instead of only one. The peak power was evaluated as 32 kW, and the GSHE can fulfil this, up to 18 kW. For higher power, the evaporative tower will supply the remainder, covering a maximum of 45%. Furthermore, the refrigeration unit may cover the cooling requirements of the entire residential and office building, without other plant improvements.
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Borodinecs, Anatolijs, Deniss Zajecs, Kristina Lebedeva, and Raimonds Bogdanovics. "Mobile Off-Grid Energy Generation Unit for Temporary Energy Supply." Applied Sciences 12, no. 2 (January 11, 2022): 673. http://dx.doi.org/10.3390/app12020673.
Abstract:
Temporary structures are being extensively used by emergency services (rescue, disaster relief, military response units), and other end-users requiring temporary mobile off-grid energy solutions for different purposes (event organization, vacation homes, summer camps, etc.). Yet energy systems for these purposes largely remain fossil-based (such as diesel generators). Although such energy systems are inexpensive, they are carbon intensive and inefficient. This study presents a methodology of simulating temporary shelter with access to an energy supply system through a mobile energy unit with renewable (PV) power supply systems to ensure on-site electricity production, as well as heating/cooling and ventilation. Digital modeling simulations have been performed for a simulated temporary shelter in different climate conditions incorporating different combinations of electricity generation systems with a fossil fuel-based solution and a PV system, using TRNSYS software. Study results show that the operation of a mobile energy generation unit can operate HVAC systems and generate electricity for temporary shelter occupants in off-grid solutions. The modeling results show that the use of a mobile energy generation unit can significantly reduce diesel consumption in temporary shelters from 54% annually (in Riga, Latvia) to 96 % annually (in Jerusalem, Israel). Furthermore, the output of PV-generated electricity is higher (in most cases) than the consumed electricity amount.
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Tharves, Mohideen, and Nagachari Nethaji. "Experimental studies on improvement of coefficient of performance of window air conditioning unit." Thermal Science 21, no. 3 (2017): 1349–58. http://dx.doi.org/10.2298/tsci141215139t.
Abstract:
This paper presents the performance analysis of a window air conditioner unit incorporated with wick less loop heat pipes (WLHP). The WLHP are located on the evaporator side of the air conditioning unit. The working medium for the WLHP is R134a refrigerant gas, an alternate refrigerant. The supply and return humidity of room air, the heat removal rat, and the coefficient of performance of the unit are analyzed for various ambient and room temperatures before and after incorporation of WLHP. The performance curves are drawn by comparing the power consumption and humidity collection rates for various room and ambient temperatures. The results show that coefficient of performance of the unit is improved by 18% to 20% after incorporation of WLHP due to pre-cooling of return air by WLHP, which reduces the thermal load on compressor. Similarly, the energy consumption is reduced by 20% to 25% due to higher thermostat setting and the humidity collection is improved by 35% due to pre-cooling effect of WLHP. The results are tabulated and conclusion drawn is presented based on the performance.
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Spanakis, Nikolaos, Peter K. Stansby, Benedict D. Rogers, and Pietro Bernardara. "Seaweed ingress of cooling water intakes with predictions for Torness power station." Journal of Ocean Engineering and Marine Energy 8, no. 1 (September 30, 2021): 31–41. http://dx.doi.org/10.1007/s40722-021-00215-w.
Abstract:
AbstractSeaweed ingress into the cooling water intakes of nuclear power stations has caused several disruptions to electricity supply. Seaweed is transported by tidal and wave-induced currents after dislodgement from the sea bed following stormy conditions but ingress will be shown to be not only determined by wave conditions. An integrated model system has been developed to predict such ingress and applied at the Torness power station in Scotland where the mass of seaweed recovered was measured for some ingress cases. Prior to each case, seaweed is assumed initially to be distributed in areas surveyed within the surrounding coastal domain with a mass per unit area based on local measurements. Criteria for dislodgement are based on near-bed velocity. Six cases where the mass of ingress was measured and two cases with no ingress have been modelled and predicted by adjusting a dislodgement factor (a multiplier on the threshold velocity) within a relatively narrow range.
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Tan, Qingkun, Lin Chen, Peng Wu, Hang Xu, Wei Tang, and Jianbing Yin. "Robust Scheduling Optimization Model for Combined Cooling, Heating and Power System in Industrial Parks." Journal of Physics: Conference Series 2160, no. 1 (January 1, 2022): 012048. http://dx.doi.org/10.1088/1742-6596/2160/1/012048.
Abstract:
Abstract The multi energy complementary system is a new power energy technology Firstly, we studied renewable energy and load uncertainties of an operation optimization system, and established the industrial park energy system, which includes wind power, photovoltaic power, a combined cooling, heating and power system, and an energy storage tank. Secondly, given the renewable energy uncertainties of unit output and load, we introduced a robust multi-objective operation optimization method for industrial park energy supply systems while considering conservative system operation. Thirdly, we examined the synergetic and game relationship among multiple objectives. The particle swarm optimization algorithm is was used to optimize the system operation scheme, reduce the feasible domain, and improve the efficiency of the solution. Finally, the simulation results show that the operation optimization method effectively uses the demand response to optimize economic and environmental objectives and ensure the optimal operation efficiency of the system under multiple uncertainties.
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Maskov, L. R., and V. Y. Kornilov. "Development of a model of an electrical complex for gas air cooling devices of gas field №1 gazprom dobycha Yamburg LLC with a centralized power supply system in the MATLAB/SIMULINK program." Power engineering: research, equipment, technology 24, no. 2 (June 13, 2022): 50–71. http://dx.doi.org/10.30724/1998-9903-2022-24-2-50-71.
Abstract:
THE PURPOSE. To develop a model in MATLAB/SIMULINK environment for the system of mechatronic movement modules (MMD) of the electrical complex, which includes gas air coolers with centralized system of power supply of the gas field 1 of "Gazprom dobycha Yamburg" LLC. To analyze the energy efficiency of MMD ETC ACHE. To perform the experimental research of the EMD EMD ETC ACHE model in the dynamic modes in order to determine the regularity of the influence of single (group) starts on the power supply source overload. To develop a switching algorithm for MMD ETK AHE at direct starts of asynchronous motors (AD), providing restoration of the technological mode within the optimum time after the voltage disappearance for the centralized power supply system.METHODS. The results presented in work are received with use of methods of the theory of electric and magnetic circuits, the theory of electric drive and electric machines, methods of optimization of power supply systems, analytical and numerical methods of applied mathematics, methods of mathematical and computer modeling.RESULTS. In article urgency of a theme is described, features of construction and modelling of ETK GP in the environment MATLAB/SIMULINK with the centralized system of power supply are considered. The comparative analysis of existing methods and calculation of parameters of the substitution schemes of the MMD ETK GP was carried out. Approximate calculation of mechanical and inertial characteristics for creating a model of load (resistance moment) for the motor. The model of EMD of electric motor drive compressor unit was created, as close as possible to the real existing system on the basis of catalog (passport) data of individual elements of electric motor drive unit. There were analyzed and developed proposals to enhance power efficiency of EMD ETC AHE and algorithms, which provide optimal direct start-up of the AHE fan group within the set time after the power failure without overloading of the power supply source, were proposed.CONCLUSIONS. On the basis of results of computer modeling, the peculiarities of operation of EMD ETH ACHE, which require further study and development of corrective measures to improve energy efficiency and reliability of power supply system of GP. Combination of direct starts of single (group) fans of ACHE, obtained at this stage of research of EMD EMD ETC ACHE model, will create the basis (algorithm) for automated control system of this complex, which will ensure restoration of technological mode within optimum time after power outage without overloading of centralized power supply source. Calculation of parameters of individual elements of MMD model of ETC AVO will allow to use data to create other models of ETC GP, which will allow to conduct in-depth research and improve the energy efficiency of the entire system of power supply of GP.