User defined HTF properties - enthalpy

Hi Paul !

I intend to use a user specific HTF fluid in my simulation but I am missing the enthalpy in my dataset.
Usually you calculate H=m*c*T, or h=c*T for it´s specific enthalpy, even though this isn´t really thermodynamically correct as you have to calculate it´s differential form deltaH=m*c*deltaT ..
When I look at the properties table for the different preselectable HTF´s (sam-htf-property-tables.xls), I get different enthalpies, so I wonder how you calculated these parameters... are they interpolated ?

Thanks for your kind reply.

Marc

Hi Marc,

You can see the equations for the HTF properties in the source code for TRNSYS Type 229: sam_mw_pt_Type229.f90. That file should be in your SAM installation folder, which by default in Windows is c:\SAM\2012.5.11\exelib\trnsys\source.

For example, the enthalpy of the Hitec fluid at 175 degrees C in the spreadsheet ( XLSX 23 KB ) is 273,000 J/kg. The equation in Line 950 of the source code file is H_salt_hitec = 1560 * T. At 175 deg C, the value is 1560 * 175 = 273,000.

Best regards,
Paul.

Hi Mr.Paul,
What will be the enthalpy calculation for fluids with varying varying specific heat ?