E Instruments E500, User Manual

Page: 71 / 75

67
ANNEX C
Optional Measurements list:
MEASURE DEFINITION
e (Exc. Air)
Air excess. Expressed as a percentage according to the formula in the annex C, is the
ratio between the volume of air actually entering the combustion chamber and the one
theoretically needed.
ΔT (dT)
Differential temperature:
It is the difference between the smoke temperature and the air combustion temperature.
Qs (LHV)
Stack losses in relation to the Lower Heating Value:
It is the percentage of dissipated heat through the stack referred to the lower heating val-
ue (LHV)
Qs (HHV)
Stack losses in relation to the Higher Heating Value:
It is the percentage of dissipated heat through the stack referred to the higher heating
value (HHV)
Ηs (LHV)
Sensible efficiency in relation to the Lower Heating Value:
It is the burner efficiency calculated as the ratio between conventional heating power and
the burner heating power. Among the combustion losses, only the sensible heat lost with
flue gasses is taken into account, thus neglecting the radiation losses and incomplete
combustion losses. This value is referred to the Lower Heating Value (LHV) of the fuel and
cannot exceed 100%.
The sensible efficiency value is to be compared against minimum efficiency stated for the
heating system performances.
ηs (Es) (HHV)
Sensible efficiency in relation to the Higher Heating Value:
It is the burner efficiency calculated as the ratio between conventional heating power and
the burner heating power. Among the combustion losses, only the sensible heat lost with
flue gasses is taken into account, thus neglecting the radiation losses and incomplete
combustion losses. This value is referred to the Higher Heating Value (HHV) of the fuel and
cannot exceed 100%.
The sensible efficiency value is to be compared against minimum efficiency stated for the
heating system performances.
ηc (Ec) (LHV)
Condensation efficiency in relation to the Lower Heating Value:
Efficiency deriving from the condensation of water vapor contained in flue gases, and it is
referred to the LHV.
ηc (HHV)
Condensation efficiency in relation to the Higher Heating Value:
Efficiency deriving from the condensation of water vapor contained in flue gases, and it is
referred to the HHV.
ηt (Eff) (LHV)
ηt = ηs + ηc
Total efficiency in relation to the Lower Heating Value:
Total efficiency. It is the sum of sensible efficiency and condensation efficiency. It is
referred to LHV (Lower Heating Value) and can exceed 100%.