Advanced Energy Systems 2nd. Edition by Nikolai V. Khartchenko, Vadym M. Kharchenko | 9781439886588 | 143988658X | Holooly

Advanced Energy Systems

130 SOLVED PROBLEMS

Question: 5.7

A dual-pressure steam turbine of a combined-cycle power plant is operating under the following conditions (refer to Figures 5.8, 5.9, and 5.11): • Gas turbine exhaust gas mass flow is mg = 590 kg/s and exhaust gas temperature is texh = 630°C • Live (HP) steam condition is p1 = 100 bar, t1 = 500°C, ...

Verified Answer:

1. After isentropic expansion in the HP and LP tur...

Question: 6.4

A combined-cycle-based cogeneration plant consisting of a gas turbine, an HRSG, and a condensing–extraction steam turbine is used for the production of power Pel and useful heat Qu. The cogeneration plant (refer to Figure 6.8) is operating under the following conditions: • Gas turbine capacity PGT ...

Verified Answer:

1. Rate of fuel energy input to the gas turbine co...

Question: 12.1

A bituminous coal is burned in a boiler furnace under the following conditions: • Coal composition (in mass fractions): C = 0.78, H = 0.07, O = 0.04, A = 0.06, and M = 0.05 • Lower heating value of coal, LHV = 31.4 MJ/kg • Oxyfuel stoichiometric combustion of coal in pure oxygen • Conventional ...

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Oxyfuel Stoichiometric Combustion of Coal in Pure ...

Question: 13.4

A hydrogen-fired combined-cycle power plant consists of a hydrogen combustor and gas and steam turbine power block. It is operating as follows: • Plant electric power output is Pel = 30 MW • Fuel: hydrogen with lower heating value, LHV = 120 MJ/kg • Lower heating value of the fuel is ...

Verified Answer:

1. Combined-cycle efficiency

\eta_{C C}=\et...

Question: 13.3

A trigeneration plant based on SOFC fuel cells stack (refer to Figure 13.8b) is employed for simultaneous production of electric power and useful heat (hot water and heat for air conditioning unit) for an industrial complex under the following operating conditions: • Power demand is Pel = 67 kW ...

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1. Trigeneration plant daily primary energy (fuel)...

Question: 13.6

A Faraday MHD generator (see Figure 13.9) is operating under the following conditions: • Electrical resistivity of the ionized gas is ρ = 0.07 Ω m • Magnetic field strength is B = 3.7 T • Plasma velocity is u = 1000 m/s • Electrode area is A = 1.4 m² • Interelectrode gap in the channel is s = 0.9 m ...

Verified Answer:

1. Open-circuit voltage

V_{\mathrm{oc}}=u\;...

Question: 13.5

A MHD generator channel with segmented electrodes (refer to Figure 13.9) is operating under the following conditions: • MHD channel volume is V = 12 m³ • Short-circuit current density Jsc of 11,000 A/m² • Electrical resistivity ρ of the ionized gas is 0.032 Ω m • Load factor K is 0.6 • Product of ...

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1. Power output of MHD generator with channel volu...

Question: 11.4

A TES has a capacity of 50 kWh over a temperature range from 40°C to 60°C. Two SHS media, water and rock, or one LHS medium and lauric acid can be used in the TES system. Determine the required mass and volume of each storage medium. The properties of the storage media are as follows: ...

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1. Storage energy density per unit mass of lauric ...

Question: 14.8

A heat pump has a heating capacity of 16 kW and a cooling capacity of 12 kW. It operates 1200 h in heating mode with a COP of 4 and 900 h in cooling mode with a COP of 3. Calculate the compressor input power, the amount of useful heat produced during heating and cooling periods, respectively, and ...

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1. Heating mode of operation (

Q_{c}

...

Question: 14.7

A vapor compression heat pump delivering 28 kJ/s of useful heat for heating pur-poses operates with a COP of 4. Calculate the compressor input power and the rate of heat addition in the evaporator. ...

Verified Answer:

1. Compressor input power

P_{\mathrm{cr}}=Q...

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