D.STEAM CALCULATION FORMULAS
1.Refer to Table 5:
a.To determine the heating capacity (Btu/hr) of a unit heater at a steam pressure and/or entering air temperature other than standard conditions of 2 lb. Steam and 60°F entering air temperature.
b.To find actual unit heater capacity when operating at
BtuA = BtuS x Heating Capacity Factor
c.To select a heater capacity based on standard conditions to meet a heating capacity at non- standard (actual) conditions:
BtuS = BtuA / Heating Capacity Factor
2.Refer to Table 6:
a.To determine the air temperature rise of a unit heater at a steam pressure and/or entering air temperature other than standard conditions of 2 lb. Steam, 60°F entering air temperature.
b.To find actual air temperature rise of unit heater when operating at
ATRA = (FATS - EATS) x Air Temperature Rise Factor
c.To find actual final air temperature of unit heater when operating at
FATA = EATA + ATRA
3.Refer to Table 7:
To determine how
Max. Mounting HeightA = Max. Mounting
HeightS x Correction Factor
4.Refer to Table 8:
To determine the rate of condensate production at steam pressures other than 2 lb.
Condensate Rate = BtuA / Latent Heat of Steam
5.Terminology:
a.ATRA = Air temperature rise at
b.BtuA = Capacity at actual operating conditions
c.BtuS = Capacity at standard conditions (2 lb. Steam, 60°F entering air temperature) from Tables 3 and 4.
d.EATA = Entering air temperature at
e.EATS = Entering air temperature at standard conditions (60°F)
f.FATA = Final air temperature at
g.FATS = Final air temperature at standard conditions from Tables 3 and 4.
h.Max. Mounting HeightA = Maximum mounting height at actual conditions
i.Max. Mounting HeightS = Maximum mounting height at standard conditions
13