IECM 12.0 beta User Manual > Modules Included with the IECM > Natural Gas Combined Cycle (NGCC) Plant > SET PARAMETERS > Overall Plant >

Performance

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The parameters on the Performance parameter screen establish the plant availability, electrical requirements, and ambient conditions for the power plant. These parameters have a major impact on the performance and costs of each of the individual technologies. The following parameters are available:

•Number of Gas Turbines: This is the number of gas turbines. Since each turbine is able to produce a fixed output, the number of turbines will determine the plant size (e.g., gross plant size). This number is shown here for reference only. You can change it on the Power Block Gas Turbine Performance parameter screen .

•Gross Electrical Output: This is the gross output of the generator(s) in megawatts (MWg). The value does not include auxiliary power requirements. The model uses this information to calculate key mass flow rates. The value here is shown for reference only. This number is controlled primarily by the number of gas turbines.

•Capacity Factor: This is an annual average value, representing the percent of equivalent full load operation during a year. The capacity factor is used to calculate annual average emissions and materials flows.

•Plant Location: This is the location of the plant. It is shown here for reference only; it may be set on the Plant Location screen in the CONFIGURE SESSION program area.

•Ambient Air Temperature (Dry Bulb Average): This is the inlet temperature of the ambient combustion air prior to entering the preheater. The model presumes an annual average temperature. Inlet air temperature affects the boiler energy balance and efficiency. It provides a reference point for the calculation of pressure throughout the system. Currently, the model cannot have temperatures below 15 degrees F or above 100 degrees F.

•Ambient Air Pressure (Average): This is the absolute pressure of the air inlet stream to the boiler. The air pressure is used to convert flue gas molar flow rates to volume flow rates.

•Relative Humidity: This is the relative humidity of the inlet combustion air.

•Ambient Air Humidity (Average): This is the water content of the inlet combustion air. This value is used in calculating the total water vapor content of the flue gas stream. The value is referred to as the specific humidity ratio, expressed as a ratio of the water mass to the dry air mass. It is calculated based on the temperature, pressure and relative humidity specified above and is shown here for reference only.