Power and Energy Measurement Units and Techniques - Energy Conversion and Management - page 13

• Lower Heating Value (LHV), also called Net Heating Value. This is the number of
heat units measured as before, the residual materials being gaseous oxygen, carbon
dioxide, sulfur dioxide and nitrogen, ash, and water vapor (the water produced
during the combustion is assumed to be discharged as water vapor). The water
vapor enthalpy, which is completely wasted, is not taken into consideration.

2.3 End User Energy Measurement Units

The energy entering a site goes through many transformations before reaching end
users (this energy is commonly called final energy). Units referring to transformed
energy rather than to purchased energy (fuels and electric energy) are conveniently
used at this stage. Table 2.8 lists the typical ranges of values for the commonest
ratios between end user and purchased energy, which depend on the efficiency of
the transformations as well as on the level of energy exploitation:
• kg steam/kg fuel;
• kg hot water/kg fuel;
• cubic meter compressed air/kWh consumed by mechanical compressor;
• kJ available for the process/kWh consumed by mechanical compressor;
• Others.

Table 2.8 Ratios between end users energy and purchased energy (see also Chaps. 18 and 20 )
Types of transformation

To convert
from

Transformation
coefficient To Unit Note

Oil Steam 12-14 kgsteam/kgoil Boiler

kgsteam/Sm 3 Natural gas Steam 9-11 Boiler

Electricity Cold fluid

(HVAC)

12,000-16,000 kJ/kWh Compressor

Electricity Cold fluid

(below ice point)

3,000-10,000 kJ/kWh Compressor

Sm 3 /kWh

Electricity Compressed

air (0.8 MPa)

9-10 Compressor

Electricity Heat 3,600 kJ/kWh Resistor

Electricity Heat 10,000-16,000 kJ/kWh Heat pump

Oil Electricity 4-7 kWh/kg Utility plant

Oil Electricity 8.5-9.5 kWh/kg Cogeneration

plant

Electricity Water storage 250-300 t m/kWh Pump

Electricity Lighting 50-100 lm/W Lamps