VorTek Pro-T, Instruction Manual

Page: 143 / 150

Series M22/M23/M24 Instruction Manual Appendix C Flow Meter Calculations
M-000-00010 C-3
Energy Flow Calculations
Energy is calculated for a steam supply/condensate return or hot/chilled water
system. For steam/water, the meter must be located in the supply line; otherwise,
the meter may be located in either the supply line or in the return line.
Steam supply, water return, meter steam supply
Energy = mdot * (h0 - pctRet * h1)
Where:
mdot = mass flow at the meter, lbm/sec
pctRet = estimated percent of mass flow returned
h0 = Steam Enthalpy (t0, p)
h1 = Water Enthalpy (t1)
t0 = steam temperature
t1 = return water temperature
p = steam pressure
Water supply and return, meter supply
Energy = mdot * (h0 - pctRet * h1)
Where:
h0 = Water Enthalpy (t0)
h1 = Water Enthalpy (t1)
t0 = supply water temperature
t1 = return water temperature
Water supply and return, meter return
Energy = mdot * (h1/pctRet - h0)
Where:
h0 = Water Enthalpy (t0)
h1 = Water Enthalpy (t1)
t0 = return water temperature
t1 = supply water temperature
The energy flow is positive if less energy is returned than is supplied. This im-
plies that chilled water systems will indicate negative energy flow. Positive and
negative energy flows are accumulated in separate totalizers.