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The 9th International Energy Conference
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:: Search published articles ::
Showing 8 results for Mea

Mohsen Fallah, Moosa Mohammadpurfard,
Volume 14, Issue 2 (7-2011)
Abstract

Power generation by Pressure Retarded Osmosis (PRO) method is a reliable approach for future. In this method, water from feed (low-salt or clean water flow) permeates through a semi membrane into a consentrated solution or a high pressurized salinity flow, such as sea water causing additional increase in its pressure and flowrate. Then this high pressure flow passing through a water turbine causes rotation of generator shaft and generates electric power. In this paper, in addition to investigate PRO power plant performance considering working condition of Iran, a PRO model is studied to predict water flux and power density under specific teoritical conditions. Model is based on empirical estimation of membrane water permeability coefficient (A), the membrane salt permeability coefficient (B) and suspended particles in solution resistivity (K).Results show that the PRO method with optimized membrane has higher specific power and greater efficiency than previous models. So, there is a growing trend into producing power via this new approach.
Azadeh Mohajer Milani, Shahin Heidari,
Volume 19, Issue 4 (1-2017)
Abstract

Limited energy resources and the need to conserve it, make the optimum and proper design of buildings in terms of energy consumption, indispensable. The type of climate in which the building is constructed in, will also decrease or increase the necessity of this attention. The objective of this study is to evaluate the effect of the window angle on the indoors Mean Radiant Temperature. For this purpose, in the present study, hot and dry climate as one of high priority in regard of energy consumption, has been selected so as to determine the right angle which will reduce the energy consumption by comparing the angle of the window and its effect on the mean radiant temperature. To achieve this goal, the South facade which receives the most exposure over the years, was selected. The daily average Mean Radiant Temperature for the whole year, simulated in ten different angle, in Energy PLus software, was calculated. According to the role in which we expect of window in summer (means avoiding exposure), and winter (means transferring radiation to the inside of the building), and with compering the results for summer and winter, angle of 75 to 80 degrees has selected as the best angle for the whole year.


Omid Deymi, Seid Alireza Zolfaghari, Majid Malek Jafarian,
Volume 21, Issue 2 (7-2018)
Abstract

The application of personalized ventilation systems, particularly in the buildings, is one of the new topics that today presented to it, because of their proper performance in reducing energy consumption and creating better thermal comfort conditions. In the current study, the energy consumption of a personalized cooling system installed in a room, considering the constraint of thermal comfort, was evaluated and compared with a non-personalized cooling system. The dimensions of the room equal to 4×3×2.7 m3 and includes a return air outlet (for both personalized and non-personalized situations), a supply air inlet in a non-personalized situation, two air inlets for personalized ventilation, table, chair and an approximate model of a human. OpenFOAM numerical solver was used for the calculation and solving the governing equations. Results indicate that in the status of the use of the personalized cooling system, Predicted Mean Vote (PMV) changes in the presence of the person is much higher than the status of the use of the non-personalized cooling system. The local thermal discomfort parameter stemming from draught is within allowed range (less than %20) for a personalized cooling system, excluding of in velocity of 2 m/s and temperature of 21.1 °C. The other important result is that the energy consumption of the personalized cooling system reported much less than the non-personalized cooling system so that energy saving was achieved in about 50 percent. In personalized cooling mode, desired conditions of thermal comfort and minimum energy consumption obtained only at the velocity of 1 m/s and temperature of 20.5 °C among the cases investigated


Minou Gholami Jourshari, Mohammad Reza Ashraf Khorasani, Isar Dashti, Saeed Asghari, Hadi Goorabi, Saeed Golshah,
Volume 21, Issue 2 (7-2018)
Abstract

In this paper we study the performance of a PEM stack fuel cell after 900 hours of operation. We tried to identify any voltage degradation and its causes. Microscopic cracks on some parts of MEA mainly due to uniformity of pressure, stress concentration and elongation of membrane in the edge of GDL has been identified as the most important cause of this gradual degradation. High contact resistance between layers of stack, including the membrane, is another cause of PEM stack degradation. All problems are solved and tested by Electrochemical Impedance Spectrometry and the best amount of thickness of the membrane is determined. The result of EIS test with optimized sealing washer shows that the stack operation was optimized with the decrease of contact resistance in the several layers of stack in the active area of membrane.


Mohsen Mohammadi, Hamed Moztarzadeh,
Volume 21, Issue 2 (7-2018)
Abstract

Article 19 of the national building regulations is one of the important strategies of modern Iranian architecture, which can help to calculate and determine building materials in a warm and dry climate for thermal comfort. In order to discover the effect of this topic on thermal comfort. In this study, through the quantitative method and PMV, the effect of nineteenth building on winter temperature has been investigated in order to improve thermal comfort. In order to investigate the performance of chapter 19 in the semi-warm and dry climate of Shiraz, temperature, humidity and wind were measured with the help of a data logger TA120 during the period from 9 am to 16 pm, and then with the help of  Fenger formula, the PMV rate and then the thermal dissipation of PPD Was obtained. the results of thermal comfort rate according to the 19th chapter of the National Building Regulations indicated that the rate of thermal comfort with the type of materials is directly related to the amount of radiation emitted by it. also, the type of materials and thermal insulation have caused the average thermal comfort in the building to be between -1.34 and +.19 degrees Celsius in winter and the amount of dissatisfaction of people from 13 pm to 16:00 in the range is favorable.
Yaser Noori, Alireza Teymourtash, Behrooz Zafarmand,
Volume 22, Issue 2 (9-2019)
Abstract

Estimation of solar radiation is one of the most important parameters in different planning such as meteorological, agricultural, hydrological, architectural, energy  and etc. In this research, we are trying to find a suitable model for estimating the intensity of solar radiation received on the surface of the earth that can be used to determine the mean daily total solar radiation in the area where the total solar radiation data is not available. Most previous studies have used regression equations or angstrom models to estimate solar radiation. In this study ، an optimal model using sunshine parameter was used to estimate the amount of solar radiation received on the earth's surface. The optimal model obtained in this study is a combination of angstrom model and linear regression method. Information of the sunshine parameter and the monthly average amount of ground radiation have been obtained from 2005 to 2019 Bojnourd meteorological station data. The results of this study were compared with other models using bias mean error (MBE) and root mean square error (RMSE) indices. The results show that the current research model compared to other existing models has high accuracy and less error.
Ms Sahar Dehnavi, Yasser Maghsoudi, Mohammadjavad Valadanzoej,
Volume 22, Issue 3 (12-2019)
Abstract

The spectral Direct Normal Irradiance (SDNI) is a basic radiometric quantity from which many other quantities can be derived. It provides not only information about the spectral and distribution of the direct solar radiation reaching a particular location. Accurate knowledge about the spectral direct irradiance shall enable us to gain new scientific results in the: determination of cloud effects, calculation of power yield of solar cells for electricity providers, derivation of aerosol distributions and their impact on the radiation field, determining the UV spectral irradiance for medical applications and in the improvement of our understanding of the radiative transfer in a changing climate. Nevertheless, at present, DNI measurements are not available in many instances. Therefore, the main objectives of this project are the setup, characterization, the calibration, the validation and the application of an operational measurement for the (SDNI) at the Institute of Meteorology and Climatology (IMUK) at the Leibniz University Hannover. With sampling times of less than one second even rapid changes of the SDNI can be recorded with a spectral resolution of about 1 nm in the wavelength range from 300 -800 nm (from UV to NIR). For this purpose three different tracking units were used to precisely track the sun location in the sky and finally based on the measurements and tracking strategy best instrument was selected. Finally the best tracking unit was used and the set-up was tested in the institute of Meteorology and climathology of Hannover (Longitude 52.37◦, Latitude 9.73◦). The comparison between the integrated value of the measurements and Pyranometer observations on the same platform, and during a complete day presented in this paper. It is worth to mention that the technique for setting up such a measurement station is very important as a basis for remote sensing research focused on the solar energy and meteorology applications.
 
Mr. Farzad Rahimi, Dr. Reza Kamranrad, Dr. Azimolah Zarei,
Volume 25, Issue 3 (12-2022)
Abstract

Due to the high share of electricity consumption in the country's industries, in recent years, various projects have been implemented, including reducing the amount of load by implementing nationwide blackouts during peak consumption times. Today, data mining is widely used as a process of discovering useful patterns from the database and one of the effective methods for analyzing, modeling and predicting energy consumption. In this study, an integrated clustering-association data mining model has been designed to investigate power consumption behavior to discover and extract the pattern from the power consumption data set of industrial units located in one of the industrial towns of Tehran province. Observations show that during the warm months of the year, the average consumption of high-consumption cluster units, which includes about 34% of the studied industrial units, is about 4.2 times the consumption of low-consumption clusters and about 1.7 times the consumption of medium clusters. By using the proposed model in this study, in addition to identifying high-consumption units and implementing smart and fair policies in forced shutdowns, it is possible to prevent damage caused by forced shutdowns and industrial units can be encouraged to optimize energy consumption. The innovative approach of this model is able to control large volumes of data for planning different areas with the aim of optimizing its energy consumption.

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نشریه انرژی ایران Iranian Journal of Energy
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