Combustion Efficiency and Room Ventilation

<...what is the air:fuel(diesel) ratio for best combustion efficiency...>

Stoichiometry is the method by which the air/fuel ratio can be calculated. From first principles try using cetane (C₁₆H₃₄) as an approximation to diesel and an oxygen concentration of 20% in air to give a first stab at the answer.

<...calculate heat dissipated from engine and generator to calculate the fresh air and exhaust air required by allowing 6 deg.c. rise in room temprature...>

It is not possible to do this without knowing:

• The rating of the engine
• What percentage of its combustion heat is being dissipated in the room
• The size of the room
• How well the room is insulated
• The outside air speed
• How well the air in the room is being agitated
• Whether there are any doors and windows, and whether these are open
• Whether there is any forced ventilation
• etc.

It may be better to simply apply forced ventilation to the room switched by a 6degC differential thermostat, and be done with it.

sir,Ive a project in hand to sound proof D.G.Room (1000 Kva.,cater pillar,2No.s) by closing all opening,insulating all 5 sides exept floor. The-heat is dissipated by engine(water-cooled) and by the generator.Aso fresh 'll be required for combustion.Sofresh air is to be thrownon to the D.G.s for cooling and combustion.The heated air is to be taken out for allowing fresh air to enter in the room.That fresh air and exhaust air is to be calculated for allowing only 6 deg.cent.rise in the room temperature than ambient temperature.Thanx.