Fresh Air Load Calc 1

[hexgalaxy]

Hi Guys,
For one of the project that i am working on we hav calculated the building load and have suggested fan coil units for most of the rooms in the bldg, the total fresh air requirement for the building is 2000 l/s, indoor condition 22-23 C @ 50% RH and the outdoor condition is DB 47 C and wb 32. How do i calculate the load in KW for selecting the FAHU??
Thank You.

 

[sspeare]

First, you need to demonstrate to the forum that you understand certain thermodynamic fundamentals - for example:

1) Do you know the definition of sensible load?
2) Do you know the definition of latent load?
3) Do you know what enthalpy is?
4) Have you used a psychrometric chart?

 

[hexgalaxy]

Hiya Sspeare,

From my understanding sensible load in terms of hvac is head load ina space that is gained by various factors such as direct exposure of sun, heat radiated by people, lights and equipment as such, in terms of thermodynamics it is the heat required to raise the temp of a body/element or may b water keepings its state constant,

latent load is essentially the humidity load with in the space or heat absorbed by a body while keeping its temperature constant while its phase changes.

Enthalpy is sum of all internal energies in a system.

and yes i hav used a psychrometric chart.

regards
thank you

 

[Drazen]

than draw your outside air and indoor design conditions in psychro chart and enthalpy difference will make your cooling capacity needed in the simplest scenario.

 

[cry22]

Q = 4.5 x CFM x Delta H

http://www.engineeringtoolbox.com/cooling-heating-equations-d_747.html