[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[TRNSYS-users] QUA and Qheat in a cube



Dear Trnsys users,

I have a cubic building with 64 m^3. The cube doesn't have any incident radiation, and its walls are only made of concrete (without windows and doors). The temperature outside the cube was set to 10 ºC. The cube doesn't have occupation, ventilation or infiltration. The only thing inside the cube is a radiator with constant value 3000 kJ/hr with no radiative part. I tried to use the internal calculation for the convective heat transfer coefficient, calculated with the constants given in "properties" of trnbuild. I defined as output Qheat (that gives me 2999 kJ/hr), QUA=UAdT (static UA transmission loss of the zone, that gives me 5600 kJ/hr) and also Qcsurf (total convection to air from all surfaces within zone, that gives me 2600 kJ/hr).
Shouldn't the values be similar?
Is there anything else I should take into consideration?
If I look to the parameters for internal calculation of heat transfer coefficients I have a constant in kJ/(m^2K) and an exponential. The heat transfer coefficient is given by "constant*(∆T)exp", so how does trnsys get units in (W/m^2K) with this expression?

Thanks in advance,

Joana Batista