Contrec 515 – HC04

Heat Calculator for stacked DP meters (ISO 5167 and V-Cones)

The 515 HC04 application measures the volume, mass and energy content of fluid in a heating or cooling system by using single or stacked differential pressure flow inputs in conjunction with feed and return temperature inputs.

A selection of fluid types and modes makes it suitable for many heating/cooling applications. Flow is calculated according to equations forISO 5167 or V-Cone meters and accurately accounts for thermal expansion.

The instrument 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.


The energy calculations are based on the IAPWS Industrial Formulation (1997). The temperature limits are dependent on the system pressure:

0 c at system pressure

32 at system pressure


volume flow = Mass flow/ρflow

Power = mass flow x (hTF – hTR)


ρflow = density at flow x conditions

hTF = specific enthalpy at feed temperature

hTR = specific enthalpy at return temperature