[TRNSYS-users] Problems in using humidity ratio

[LE GALL, Jace]

Dear All,

 

I am currently using TRNSys to model an HVAC installation but when using
the weather data from humid regions such as Singapore or Hong Kong, I
have a recurrent message on different units such as Type52b cooling
coil, Type667c heat recovery wheel and Type88 single zone model.

 

Message : The referenced UNIT as called the PSYCHROMETRICS routine one
or more times during the simulation withan enthalpy greater than that
for saturated air and the given dry bulb temperature. The air was
assumed saturated and the enthalpy set for this condition.

 

I assume that this error leads to more errors in the final energy given
as a result and eventually, even manage to crash my simulation when I
lower the time step too much, as the number of messages is limited to
500. I based my calculations on the hypothesis that the humidity ratio
asked in the different units is the absolute humidity ratio with is kg
of water / kg of dry air.  I have isolated Type52b cooling coil to
search more deeply my possible mistakes (constant humidity ratio of
0.02kgw/kga and wet bulb temperature varying from 27 to 33). According
to my psychometric chart (at sea level), the air shouldn't reach
saturation but TRNSys tells me the opposite.

 

Has anyone encountered a similar problem in a simulation and was able to
solve it?

 

Best Regards,

 

Jace LE GALL


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