Power Generation in an IC Engine-Generator: Oper. Conds Tab

Variable Definitions, Ranges and Default Values

The following table shows a brief description of the variables appearing in this tab. The table also displays their default values and their generally acceptable range.

Variable	Default Value	Range

○ Air Stream Indicates the input port that is connected to the air stream. If an input stream is already present at the selected port, then the button next to the selection is active. Click on the button to bring up the attached stream’s simulation dialog in order to provide its composition.	<None>	Designated Air Stream
◙ Excess Oxygen (%) The excess oxygen % of the air stream.	80.0	Positive
◙ Air-Fuel Ratio The ratio of the mass flowrate of the air stream to the mass flowrate of the fuel stream.	0.0	Positive
● Stoichiometric Air-Fuel Ratio The minimum air-fuel ratio required for stoichiometric combustion.	0.0	Positive
● Air Throughput per Unit The volumetric flow rate of inlet air per equipment unit.	0.0	Positive
● Heat Input (LHV) (kW) The total thermal energy input of the fuel based on LHV.	0.0	Positive
○ Heat Losses (%) The total heat that is lost to the surroundings expressed as a percentage of the fuel heat input.	5.0	0-100
○ Exhaust Gas Temperature (^oC) The temperature of the exhaust gas.	400.0	0-100
○ Exhaust Gas Pressure (bar) The pressure of the exhaust gas.	1.013	Positive
● Heat Dissipation (kW) The total heat that must be rejected/recovered.	0.0	Positive
● Cooling Duty (kW) The total heat transfer rate from the engine to the cooling agent.	0.0	Positive
○ Cooling Agent Name Indicates the cooling agent used for the operation. Click on the list box to bring up a list of available cooling agents in order to select one.	<Chilled Water>	Any Cooling Agent
● Inlet Temp. (^oC) The inlet temperature of the cooling agent.	5.0	Positive
● Outlet Temp. (^oC) The outlet temperature of the cooling agent.	10.0	Positive
● Rate (kg/h) The mass flow rate of the cooling agent.	0.0	Positive
○ Heat Transfer Effic. (%) The heat transfer efficiency of the cooling process.	100.0	(0,100)
○ Cold Water Stream Indicates the input port that is connected to the cold water stream. If an input stream is already present at the selected port, then the button next to the selection is active. Click on the button to bring up the attached stream’s simulation dialog in order to provide its composition.	<None>	Designated Cold Water Stream
○ Include Heat Recovery? Check this box to indicate that the dissipated heat will be .	No	Yes/No
○ Heat Recovery (%) The total heat recovery from the engine coolant, lube oil and intercooler expressed as a percentage of the fuel heat input.	100.0	0-100
○ Hot Water Temp. (^oC) The temperature of produced hot water.	80.0	Positive
○ Power Type Indicates the power type that is used by the operation. Click on the list box to bring up a list of available power types in order to select one.	<Std Power>	Any Power Type
○ Thermal Efficiency (%) The percentage of fuel heat input that is converted into mechanical power output.	0.0	0-100
● Mechanical Power (kW) The mechanical power output of the IC engine.	0.0	Positive
○ Generator Efficiency (%) The electric generator’s efficiency of conversion of mechanical power to electric power.	96.0	0-100
● Electric Power The total electric power output of the operation.	0.0	Positive
● Electrical Efficiency (%) The percentage of fuel heat input that is converted into electrical power output.	0.0	0-100
○ Setup Time The amount of time (per cycle) spent before each operation is carried in preparation for the actual execution of the operation. It may involve actions like cleaning, vacuuming, setting up of equipment, etc. which the user opted not to model explicitly.	0.0	Positive
◙ Process Time (min) The actual duration of the operation (per cycle). It can be either set by user or set by a master-slave relationship.	60.0	Positive
○ Ignore Labor? Check this box to ignore labor for this operation. This option is used only if the process time is set by a master-slave relationship.	Yes	Yes/No

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Specification Choices / Comments

The following list describes the available specification choices in this tab; for more details on how these are implemented, see Power Generation in an IC Engine-Generator: Modeling Calculations.

•Air flow specification options...

You may choose to either specify the percent excess oxygen of the air stream or the air-fuel ratio.

•Heat Recovery/Cooling Duty...

By default, the “Include” heat recovery option is not checked, and the entire heat that must be dissipated is transferred to the cooling agent. If the above option is checked, then you must specify the percent of total heat dissipation that is recovered by a cold water stream (turning it into hot water) and the temperature of the hot water that is produced. If the specified percentage is less than 100%, then the remaining percentage is assumed to be transferred to the cooling agent.

•Duration options...

Duration options are only available in batch mode. You can set the process time, or have the process time calculated based on air throughput, or match the duration of this operation to the duration of another operation by introducing a master-slave relationship between the two operations. If you introduce a master-slave relationship, the program will match the setup time, the process time and the turnaround time of this operation (the ‘slave’) with the corresponding times of the reference operation (the ‘master’ operation). For more details on how to setup a master-slave relationship, see The Scheduling Tab.