Liquid Controls SP4000 - Manual (Page 27)

SP4000 Flow Computer
24
3.12 Steam Delta Heat
Measurements:
Measures actual volume flow and pressure of the saturated steam in the supply piping
as well as the temperature of the condensate in the downstream piping of a heat
exchanger.
Calculations:
• Calculates density, mass flow as well as the delta heat between the saturated steam
(supply) and condensation (return) using physical characteristic tables of steam and
water stored in the flow computer.
• The saturated steam temperature in the supply line is calculated from the pressure
measured there.
Input Variables:
Supply: Flow and pressure (saturated steam)
Return: Temperature (condensate)
Output Results:
• Display Results
Heat, Mass or Volume Flow Rate, Resettable Total, Non-Resettable Total,
Temperature, Pressure, Density (optional: peak demand, demand last hour,
time/date stamp)
• Analog Output
Heat, Mass or Volume Flow Rate, Temperature, Pressure, Density, Peak
Demand, Demand Last Hour
• Pulse Output
Heat, Mass or Volume Total
• Relay Outputs
Heat, Mass or Volume Flow Rate , Total, Pressure, Temperature Alarms, Peak
Demand, Demand Last Hour
Applications:
Calculate the saturated steam mass flow and the heat extracted by a heat exchanger
taking into account the thermal energy remaining in the condensate.
STEAM DELTA HEAT
Delta Heat Flow
Net Heat Flow = Volume flow • density (p) • [E
D
(p)– E
W
(T)]
E
D
= Specific enthalpy of steam
E
w
= Specific enthalpy of water
Note: Assumes a closed system.
Calculations
Steam Delta Heat
Illustration
Flowmeter
Temperature
Transmitter
PRINT
5
0 –
TIME
CLEAR
•
MENU
ENTER HELP
TEMP
4
PRE 1
3
RATE
2
TOTAL
1
GRAND
6
SCROLL
7
PRE 2
8
DENS
9
Pressure
Transmitter
Water
Saturated
Steam