Boiler Systems
1. 1% excess air reduction will increase 0.6% the efficiency of combustion in the boiler.
2. Feed water and Blow-down TDS of a boiler should be lesser than 100 ppm and 3500 ppm respectively.
3. 20-degree Celsius rise in inlet air of the boiler increases thermal efficiency by 1%.
4. Pressure drop of steam should be below 0.1 bar per 50m of transmission
5. Every 22°C increase in temperature in the boiler reduces thermal efficiency by 1%.
6. Every 3mm soot in the boiler increases fuel consumption by 2.5%
7. Install all steam pipes with a fall of 1% [1:100] in direction of steam flow toward steam traps.
8. 1% gas can be saved for every 200 C rise in air temperature.
9. 1 Kg of natural gas requires 17 kg of air for combustion. If we include 5% of excess air it should be 17.85 Kg air for burning properly 1 kg of natural gas.
10. The conversion efficiency of heat exchanges (Economizer, air pre-heaters, recuperator etc. is 60-65%).
11. Waste Heat Boiler (WHB) produces 500 kg steam per 1,000 kW heat input.
12. Increase in feed water temp by 60C reduces fuel consumption by 1%.
13. 10% reduction in excess air improves Boiler efficiency by 1%.
Air Compressors
1. 4 degree Celsius rise in air compressor inlet air temperature increases the energy consumption by 1%
2. Increasing pipe diameter from 1 ½” to 2” reduces Pressure Drop by 75% of air compressor.
3. Design the header size of the compressor to maintain air velocity below 6 m/sec and a maximum pressure drop of 2 psi in the compressor room.
4. Design the piping to maintain air velocity below 9 m/sec and a maximum pressure drop of 3 psi to the farthest point of use from an air compressor.
5. In a compressor reduction of one discharge pressure by one kg/cm2 normally saves power by 9-10 %.
Induction Motors
1. An imbalanced voltage can de-rate the motor by 3 – 5%
2. 5% or more voltage drop observed at motor input, while motor shifts to high load, indicates undersized cables
3. Star connection reduces the voltage across the motor windings to 58% of the Delta connection
4. For every 10°C increase in motor operating temperature over the recommended peak, the motor life is estimated to be reduced by 50%.
5. Motors consuming 5% or more power at Zero-load conditions indicate increased losses and should be replaced.
6. If rewinding is not done correctly, the efficiency can be reduced by 5 – 8%
Electrical Systems
1. Replacement of T8 lights with T5 lights saves Energy by 25%.
2. Heat rate of waste heat recovery power plant is 4,000 Kcal/kWh.
3. Pl. add one 2.24PKR/kWh towards the capital cost, financing charge, O & M, etc. while calculating the cost of kWh generation from gas generators.
4. 1 Ton AC requires 3,000 Kcal /hr.
5. Insulation cost is PKR 17962 per square meter for the HVAC system.
6. Cost of high efficient motor with an inverter is PKR 4939 per kW power rating.
7. Cost of VFD/Inverter is PKR 15717 per kW power rating.
8. Energy management can save up to 2% of the overall energy consumed by the plant.
34. Every 1°C increase in the set temperature of air conditioner reduces the power consumption by 3%.
Published By: Ghulam Kafeel
Written By: Hafiz Umer Habib