8.7 A point-focus concentrating solar collector compriIsıng a heliostat field and central receiver and a steam turbine-generator unit (refer to Figure 8.8) is operating under the following conditions: • Power plant electric power output Pa= 75 MW • Single heliostat surface area A, = 125 m² • Beam solar radiation flux incident on the heliostat Ian = 835 W/m² • Heliostat-receiver concentration ratio C = 510 • Efficiency of solar collector, that is, heliostat field and central receiver n = 0.69 • Efficiency of the power plant cycle and turbine-generator unit Nag =0.36 • HTF in the receiver: molten salt (sodium potassium nitrates) with spe- cific heat e of 1.03 kJ/(kg K) • HTF temperature rises in the absorberfreceiver from 298°C to 563°C, that is, AT, = 265 K Calculate (i) the overall (electrical) efficiency of the power plant, (ii) the rate of useful heat output of the central receiver/absorber, (iii) the total reflecting surface area of the heliostat field, (iv) the number of heliostats and absorber surface area in the central receiver, and (v) the HTF mass flow rate.

8.7 A point-focus concentrating solar collector compriIsıng a heliostat field and central receiver and a steam turbine-generator unit (refer to Figure 8.8) is operating under the following conditions: • Power plant electric power output Pa= 75 MW • Single heliostat surface area A, = 125 m² • Beam solar radiation flux incident on the heliostat Ian = 835 W/m² • Heliostat-receiver concentration ratio C = 510 • Efficiency of solar collector, that is, heliostat field and central receiver n = 0.69 • Efficiency of the power plant cycle and turbine-generator unit Nag =0.36 • HTF in the receiver: molten salt (sodium potassium nitrates) with spe- cific heat e of 1.03 kJ/(kg K) • HTF temperature rises in the absorberfreceiver from 298°C to 563°C, that is, AT, = 265 K Calculate (i) the overall (electrical) efficiency of the power plant, (ii) the rate of useful heat output of the central receiver/absorber, (iii) the total reflecting surface area of the heliostat field, (iv) the number of heliostats and absorber surface area in the central receiver, and (v) the HTF mass flow rate.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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A point-focus concentrating solar collector comprising 490 heliostats and a central receiver atop a tall solar tower (see Figure 8.5) is operating under the following conditions: • Beam solar radiation flux incident on the heliostat Ib,N = 830 W/m2 • Single heliostat surface area Ah = 120 m2 • Heliostat–receiver concentration ratio C = 520 • Optical efficiency of the heliostat–receiver system ηopt = 0.8 • Effective overall heat loss coefficient of the absorber/receiver Uc.e = 35 W/m2K • HTF: molten salt • HTF temperatures at the receiver inlet and outlet Tin = 333°C and Tout = 565°C • Ambient temperature Ta = 36°C • HTF specific heat c = 1.03 kJ/(kg K) Calculate • Efficiency of the collector • Mass flow rate of the HTF
A point-focus concentrating solar collector comprising 490 heliostats and a central receiver atop a tall solar tower (see Figure 8.5) is operating under the following conditions: • Beam solar radiation flux incident on the heliostat Ib,N = 830 W/m2 • Single heliostat surface area Ah = 120 m2 • Heliostat–receiver concentration ratio C = 520 • Optical efficiency of the heliostat–receiver system ηopt = 0.8 • Effective overall heat loss coefficient of the absorber/receiver Uc.e = 35 W/m2K • HTF: molten salt • HTF temperatures at the receiver inlet and outlet Tin = 333°C and Tout = 565°C • Ambient temperature Ta = 36°C • HTF specific heat c = 1.03 kJ/(kg K) Calculate • Total aperture area of the heliostat field • Collector useful heat output rate
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