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Equation of a system energy provided to the zone in EnergyPlus engineering reference

asked 2018-04-24 23:53:21 -0500

tobeabest gravatar image

In Eq (2.3) at Engineering reference v.8.5.0 is as follows. Qsys=msys x Cp x (Tsup – Tz) (2.3)

where Qsys is system energy provided to the zone, msys is system air flow rate, Cp is zone air specific heat, Tsup is supply air enthalpy, Tz is enthalpy of the air leaving the zone. There are no units in document.

So, I guess, Qsys is W, msys is kg/s or CMH, Cp is kJ/kgK, Tsup and Tz are kJ/kg. In this case, overall units do not match.

Am I wrong or typo?

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answered 2018-04-25 09:18:13 -0500

updated 2018-04-25 10:25:34 -0500

Tsup and Tz are temperature in C. I think you are confusing these 2 equations:

Q = Mdot * Cp * (Tsup - Tz)


Q = Mdot * (Hsup - Hz)
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Asked: 2018-04-24 23:52:18 -0500

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Last updated: Apr 25 '18