Contrec 515, Руководство по эксплуатации

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Introduction
2 515 HC04 - 8 June 2007
The energy calculations are based on the IAPWS Industrial Formulation
(1997) for the thermodynamic properties of steam. The temperature values
are used to determine the density and specific enthalpy. The instrument also
calculates the isentropic exponent and absolute viscosity which are required
for the differential pressure calculations.
Operation Modes
This instrument can be used for various heating and cooling energy delivery
systems by selection one of the following operation modes in calibration:
•
HEAT - Heating mode is used when the application is for heating
only and assumes that the Feed Temperature will always
be higher than the Return Temperature (positive
∆
t). If the
Feed Temperature is lower than the Return Temperature
(negative
∆
t), then no Energy is totalised however
Volumetric Flow is still calculated.
•
COOL - Cooling mode is used when the application is for cooling
only and assumes that the Feed Temperature will always
be lower than the Return Temperature (negative
∆
t). If the
Feed Temperature is higher than the Return Temperature
(positive
∆
t), then no Energy is totalised however
Volumetric Flow is still calculated.
•
BOTH - This mode caters for applications where the flow of
Energy may be for Heating or Cooling. In this mode
Energy is increased regardless of whether the
∆
t is
positive or negative.
Calculations
The following equations identify the derivation of some of the displayed
variables. If your interest is more in the operation of the instrument, you can
skip this section and allow the instrument to take care of the calculations.
The energy calculations are based on the IAPWS Industrial Formulation
(1997). The temperature limits are dependent on the system pressure:
0
°
C < t < t
saturation
at system pressure
32
°
F < t < t
saturation
at system pressure
Formulas
Volume flow = Mass flow /
ρ
flow
Power = Mass flow x (h
TF
- h
TR
)