What is "Zone Air System Sensible Heating Energy"?

asked 2020-03-05 11:04:40 -0600

nagpalh
75 ●5

updated 2020-03-05 20:21:39 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

Could anyone explain to me clearly that what "Zone Air System Sensible Heating Energy " means? From the EnergyPlus documentation, my understanding is that even if the heating coil is not on, this variable can have a positive value, because it includes the heat added from the fan and OA as well.

Are there any other parameters which add to "Zone Air System Sensible Heating Energy "?

answered 2020-03-05 11:15:40 -0600

rraustad

13834 ●79 ●12 http://www.fsec.ucf.edu/

The air system is directing an air stream into the zone at some air mass flow rate. That air stream will typically have a different temperature and moisture content than the zone. The difference between the air stream's air properties and the zone's air properties is the basis for the cooling or heating sensible or latent energy transfer. It does not matter if a coil is on or off, or even present in the air stream. What matters is the difference in air temperature, or other air property, from the zone conditions.

Qtotal = Mdot * (Hin - Hzone)

Qsensible = Mdot * CpAir * (Tin - Tzone)

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Just an another follow-up question, if I am asked what is the heating/cooling requirements of the building to maintain certain set point temperatures, would that be the sensible heating/cooling energy provided by the heating/cooling coils or the sensible heating/cooling provided by the Air system?

nagpalh ( 2020-03-05 12:28:24 -0600 )edit

The loads are found in:

Output:Variable,*,Zone Predicted Sensible Load to Setpoint Heat Transfer Rate,hourly;
Output:Variable,*,Zone Predicted Moisture Load Moisture Transfer Rate,hourly;

However, these will be exaggerated if the zone does not maintain set point (i.e., more energy is required to get back to the set point). The Air System Sensible * Rate reports will match these if the zone temperature is maintained (and RH set point if controlling RH).