فهرست مطالب

Energy Equipment and Systems - Volume:10 Issue: 1, Winter 2022

Energy Equipment and Systems
Volume:10 Issue: 1, Winter 2022

  • تاریخ انتشار: 1400/12/10
  • تعداد عناوین: 6
|
  • Mehdi Ahmadi Jirdehi *, Reza Hemmati, Sadjad Galvani Pages 1-11
    This paper presents a new algorithm for validation (identification and correction) of measurement and parameter errors (branch parameters as well as unified power flow controller (UPFC) parameters), simultaneously. The algorithm is composed of three steps. First, in the step 1, state estimation (SE) is solved by the modified weighted least square (MWLS) and then, the normalized measurement residual and Lagrange multiplier vectors are computed. The errors in measurement and parameter are identified in the step 2. Finally, in the step 3, erroneous measurement and parameter values are corrected. The correction algorithm is based on a proposed approach without the using of augmented state vector (ASV). The IEEE-14 bus system and 230 kV East Azerbaijan network of Iran modified by incorporating UPFC are used as test systems. Simulation results demonstrate the effectiveness of the proposed method. Also, results indicate that the proposed method can validate the erroneous values with lower error percentage
    Keywords: State Estimation, MWLS, UPFC, Measurement Errors, Parameter Errors, East Azerbaijan Network of Iran
  • Nader Alihosseini, Babak Mohammadi, Mohammad Eftekhari Yazdi, Gholamreza Salehi * Pages 13-26
    The purpose of this study is to evaluate the impact of moving the condenser of a household refrigerator within the body on the refrigerator's performance and energy consumption. The effects of the internal and external condensers on energy consumption and cooling capacity in a household refrigerator are next explored. This study was conducted experimentally and in a laboratory setting, and all terms and conditions were in accordance with the international electrotechnical commission 62552-2015 for cooling system testing. The studies were conducted in a 5-foot refrigerator. On this refrigerator, both internal and external condenser models were installed. In the first situation, the internal condenser was inserted into the cooling cycle and the associated tests and calculations were performed. In the other situation, the internal condenser was removed from the cooling cycle and the external condenser was replaced by changing the valve status. In this case, the relevant diagrams and calculations were obtained and analyzed. Based on the findings of this study, it can be stated that using the internal condenser reduces energy consumption and, as a result, has a higher energy grade than using the external condenser. The internal condenser in the heat transfer process work better than the external condenser, based on the temperatures obtained. An internal condenser is also a preferable solution for a household refrigerator in terms of installation and cost.
    Keywords: Refrigerator, Cooling Cycle, Internal Condenser, External Condenser, Energy Grade
  • Akram Jahanbakhshi, Afshin Ahmadi Nadooshan *, Morteza Bayareh Pages 27-40
    In the present study, two cases of a microchannel heat sink are studied: i) with 50 wavy channels, and ii) with the addition of wavy tubes. Also, the effect of nanofluid Ag/water-ethylene glycol 50% is investigated. ANSYS Fluent software was used to solve the equations expressed in the problem geometry. To solve the momentum equation, the second-order UPWIND method is used. Also, the SIMPLEC algorithm with a staggered pressure grid is employed to couple velocity and pressure fields. The results show that the addition of a microtube significantly increases the overall thermal coefficient of the system because despite the microtube and having two different geometries in a heatsink at the same time, the heat exchange between the body and the fluid increases so that in a flow without a microtube with Reynolds number 300, the average surface temperature is 315 , but the addition of a microtube reduces this temperature to 309 , which is equal to 6 degrees. Also, as the Reynolds number (Re) increases, the effect of increasing the concentration of nanoparticles enhances. The results demonstrate that the thermal entropy generation ( ) decreases at high values of Re. In addition, the decrease in frictional entropy generation ( ) due to the increase in nanoparticles is directly related to their concentration and independent of Re. So that the Percentage of decrease in friction entropy due to an increase in nanoparticle concentration relative to the pure fluid is equal to 1% for a concentration of 0.1% and 9% for a concentration of 1%. It is revealed that total entropy generation ( ) and  do not exhibit the same behavior.
    Keywords: Numerical study, Micro Heatsink, Entropy, Wavy Channel, Bio Nanofluid
  • Omid Ziaee, Naeem Zolfaghari, Mostafa Baghani, Majid Baniassadi, Kui Wang * Pages 41-49
    Lithium-ion batteries are the dominant energy storage tools for electric vehicles and portable devices. Their prospects depend on the development of new electrode materials. The electrode properties are highly affected by phenomena on the electrode’s surfaces. Besides experimental means, there are various simulation ways to investigate these phenomena where experiments have difficulty analyzing. However, simulating some of these events is challenging for existing simulation methods, and researchers are looking for new simulation tools to fill this gap. Here, we focus on developing and evaluating a new method for studying the key surface phenomenon inside a battery electrode in nanoscale, i.e., adsorption. In particular, we are interested in the adsorption behavior of ions on the surface of a nanosized electrode. We developed a general cellular automata model for studying the adsorption behavior of various materials, where desorption and intercalation happen during an adsorption process. The model results are compared with Freundlich isotherm and show a high resemblance. Also, an experiment concerning the lithium-ion adsorption on Titania nanotube is modeled with our C.A. model. The model is highly time-efficient and exhibits spectacular performance for simulating relatively complex systems as the results are quite close to the experimental results. As this model is general, its local rules and parameters can be modified and calibrated easily with either experiment or simulation, enabling one to study various sorption behaviors.
    Keywords: Lithium-ion battery, Adsorption, cellular automaton, Freundlich Isotherm
  • Yousef Gorji Mahlabani, Maryam Yaghoubi Moghaddam, Mohammad Hakim Azari, Farschad Torabi * Pages 51-71

    In order to supply the thermal load of a building, a huge amount of energy is consumed. Therefore, it is necessary to use renewable energy sources in today’s architecture. As a matter of fact, this issue has begun to be the focus of many studies worldwide making the topic even more interesting. In this regard, the wind has always been known as an outstanding renewable source of energy used in Iran for thousands of years. Windcatchers, known as Badgirs in Iran, are notably used in warm-humid and hot-dry climates to make the best use of wind energy in these areas. However, Badgirs are neglected in today’s life due to the limitation associated with their use in modern buildings. Accordingly, the current study aims to take into account some advantages of the windcatchers (Badgirs) in addition to highlighting their effect in both reducing energy consumption and providing thermal comfort. In previous research, humidification and similar solutions have been used to provide cooling and heating by a windcatcher, however, in none of them the Ground source heat pump system has not been used for this purpose. This study proposes a system consisting of a windcatcher and a Ground Source Heat Pump system for a building in Yazd, Iran. For this purpose, the study is conducted in three steps. First, current literature is studied. Second, the proposed system is simulated using Transys software. Finally, a mathematical calculation is performed. The simulation model consists of a room located in Yazd with width, length, and height of 4m, 6m and 3.5m, respectively. The findings show the positive effect of the proposed system in improving thermal comfort and energy by about 37.6% in summer and 7% in winter.

    Keywords: Windcatcher’s Efficiency, Ground Source Heat Pumps System, energy consumption, Thermal comfort
  • Samira Zare, Moosa Ayati *, MohammadReza HaIri Yazdi, Amin Kabir Anaraki Pages 73-82

    Between different sources of renewable energy, wind energy, as an economical source of electrical power, has undergone a pronounced thriving. However, wind turbines are exposed to catastrophic failures, which may bring about irrecoverable ramifications. Therefore, they necessarily need condition monitoring and fault detection systems. These systems aim to reduce the number of attempts operators are required to do through the use of smart software algorithms, which are able to understand and decide with no human involvement. The gearboxes are usually responsible for the WT breakdowns. In this paper, convolutional neural networks are employed to develop an intelligent data-based condition-monitoring algorithm to differentiate healthy and damaged conditions that are evaluated with the national renewable energy laboratory (NREL) GRC database on the WT gearbox. Since it is much easier for convolutional neural networks to extract clues from high dimensional data, time-domain signals are embodied as texture images. Results show that the proposed methodology by utilizing a 2-D convolutional neural network for binary classification is capable of classifying the NREL GRC database with 99.76% accuracy.

    Keywords: Wind Turbine, Gearbox Condition Monitoring, Convolutional Neural Networks (CNN), Imaging Time-Series