Showing 4 results for Jafarmadar
Mehran Abdolalipouradl, Shahram Khalilarya, Samad Jafarmadar,
Volume 18, Issue 4 (8-2018)
Abstract
The use of new energies, including geothermal energy, is rapidly devoloping in the world. In Iran, the Sabalan area has a great potential for generating energy from geothermal energy sources. In this paper, a new power generation combined cycle (flash combined cycle with supercritical carbon dioxide and organic Rankine cycle) is proposed with respect to two wells with different temperatures and pressures for Sabalan geothermal sources. For the organic Rankine cycle, four fluids are considered appropriately and then proposed combination cycle is investigated by energy and exergy analysis. In this study, a new method proposed for the determination of Pinch point for carbon dioxide heat exchangers. In the end the proposed cycle has been optimized relative to seprators pressure, the second evaporator temperature and the carbon dioxide cycle pressure ratio. The results show that the n-butane agent has been selected as the most suitable fluid for the Rankine cycle. For the optimal condition, the net power of the proposed cycle is 19934 kW, the cycle efficiency will be 17.05% and the exergy efficiency will be65.38 %.The results of exergy analysis show that the low pressure turbine in geothermal have the highest value of exergy destruction. The results show that net power output, energy and exergy efficiencies of the proposed cycle in this paper is 15.29 %, 17.06% and 18.35% higher than the corresponding values obtained for the previously proposed system.
Naghi Aghazadeh, Shahram Khalilarya, Samad Jafarmadar, Ata Chitsaz Khoyi,
Volume 18, Issue 7 (11-2018)
Abstract
In this article, a new power, cooling and heating cogeneration system consisting of a solid oxide fuel cell (SOFC) - gas turbine (GT), a heat recovery steam generator (HRSG), Generator-Absorber-heat eXchange (GAX) absorption refrigeration cycle and a heat exchanger for heat recovery (HR) has been studied from a thermodynamic and economic perspective. The modeling of this cycle was done by solving the electrochemical, thermodynamic and exergoeconomic equations for fuel cell and system components, simultaneously. The results showed that the exergy of our proposed combined cycle is 14.9% more and the irreversibility rate of this cycle is 10.6% less than that of the combined SOFC-GT-GAX systems in the same conditions. Also, the fuel cell and the afterburner have the highest rate of exergy destruction among other components due to irreversibility. Exergoeconomic analysis showed that the sum of uint cost of products (SUCP), the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate for the overall system is equal to 331.1 $/GJ, 29.3%, 10.47 $/h and 25.32 $/h, respectively. Parametric studies showed that increasing the current density will increase the net electrical power, heating capacity of HRSG and HR heat exchanger, cooling capacity and total irreversibility. Also, with increasing of the current density, both the exergy efficiency and SUCP decrease.
M. Abdolalipouradl , Sh. Khalilarya , S. Jafarmadar ,
Volume 19, Issue 2 (February 2019)
Abstract
In northwestern Iran, two wells with different temperature and pressure conditions have been exploited in Sabalan region. According to the thermodynamic properties of wells, the combined cycle (flash combined cycle with transcritical CO2 and Kalina 11) is proposed for Sabalan geothermal. In the Kalina 11 and transcritical CO2 heat exchangers, in which the fluid temperature is rising, there is a different temperature variation gradient, therefore, a new method is proposed for the determination of pinch point and other thermodynamic properties. The effects of the Kalina high pressure, amoina concentration, transcritical CO2 cycle pressure ratio, pinch points temperature difference and separators’ pressure on the thermal and exergy efficiencies of the proposed combined cycle were studied, Finally the proposed combined cycle was optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on identical operation conditions, the net power of the combined cycle is 20046 kW, the thermal efficiency is 17.15%, the rate of exergy destructions is 8259 kW and the exergy efficiency is 65.74%. It was found that the net power output, the thermal and exergy efficiencies of combined cycle are about 17.55%, 17.55% and 18.35% higher than the previously proposed system.
M. Talei, S. Jafarmadar, Sh. Khalilarya,
Volume 20, Issue 1 (January 2020)
Abstract
In the present research, the performance of a single-cylinder engine with a pre-chamber and natural gas fuel designed in Urmia University has been investigated and the effect of Exhaust Gas Recirculation (EGR) on engine performance has been analyzed. The results indicate that the simultaneous use of the pre-chamber and the EGR reduces significantly nitrogen oxides emission. Also, the amount of unburned hydrocarbons (HC) decreases in the low EGR, but the amount of HC increases significantly with higher EGR. EGR increases the carbon monoxide (CO) emission but does not have a significant effect on carbon dioxide (CO2) emission. Simultaneous use of EGR and pre-chamber can reduce the amount of emission while it can maintain the engine braking. The engine power and the indicated mean effective pressures (IMEP) which are the main indicators of the engine's performance, decrease by 3 to 4 percent for every 5 percent of the EGR. The results show that the EGR reduces the velocity of the jet flames out of the pre-chamber which ultimately reduces the advance of the flame front. Analysis of the results of the experimental test and the simulated model shows that an ideal range for EGR in an engine with a pre-chamber can be defined in which the emission is minimal and the engine power is maintained. In the engine used in this research, the exhaust gas reaction is in the ideal 10% range.
