Problems with writein answers The specifications of Capstone

Problems with write-in answers The specifications of Capstone c30 microturbine are given below. Rating: 30 kw Electrical Efficiency LHV: 26% Combined Heat And Power Efficiency: Up to 90% Voltage: 400-480 VAC Frequency: 50/60 Hz, Grid Connect 10-60 Hz, Stand Alone Electrical Service: 3-Phase, 4-Wire Width: 0.76 m (30 in) Depth: l.5 m (60 in) Height: l.8 m (70 in) Weight: Grid Connect - 405 kg (891 lb); Dual Mode - 578 kg (l, 27l lb) Net Heat Rate LHV: 13.8 MJ/kWh (13, 100 BTU/kWh) Exhaust Temperature: 275 degree C (530 degree F) Exhaust Gas Flow: 0.31 kg/s (0.68 lbm/s) Determine the amount of heat recovered based on the CHP efficiency of 90%, the annual fuel consumption of the turbine based on the electrical efficiency assuming the capacity/plant factor is 80%, and the annual saving in the fuel consumption due to cogeneration. solid oxide fuel cell operates at 800 degree C whereas PEM fuel cell operates around 200 degree C. compare their Carnot efficiency if the ambient is at 20 degree C. A fuel cell stack has a rated power output of 250 kW_e. if the fuel cell has a thermal efficiency of 45 percent and the fuel is hydrogen, estimate the air flow required to provide the necessary oxygen? The reaction inside the fuel cell can be taken as

Solution

1.the amount of heat recoverd based on chp efficiencey

use this formula

EE =we/(QFUEL – (QTH / ) EE )

substitute all values in the given

2.annuel fuel consumption of turbine bases on electical efficiency

The efficiency of any turbine or engine can be defined as its ability to convert the input energy into useful output energy which is expressed in the form of the following equation.

Efficiency () = Output / Input

An ideal turbine with 100% efficiency is the one which converts all its input energy into output work without dissipating energy in the form of heat or any other form. But in the real world, it is not possible to build a turbine with 100% efficiency because of friction in the parts of turbines, heat loss, and other such losses. In the case of steam turbines factors decides the overall efficiency f the turbine.