Need assistance in HAP 1

[mechbuild]

Hi,
Do we have to consider ceiling partition when we use ceiling space as return air plenum and also what percentage of wall heat gain to be cosidered.

What should be the height of the wall? (from finished floor to ceiling or from finished floor to slab).

 

[walz]

Do not consider the ceiling plenum unless your ceiling is non-conditioned. Consider the full height of wall (finished floor to finished floor) and yes you may take the percentage of wall heat gain to the plenum. e.g, if finished to finished floor height is 4 meter. and your ceilng height is 3 meter. In the systems input under system components - duct system, chose the option return air via return air plenum, then input wall heat gain to plenum as 25%. in this case your load will be the same but room supply air quantity will be lesser than the case you had not chosen the return air via plenum.

You can do this load twice, once with plenum and once without. You'll notice that the load in both will be same, in case of return air via plenum, the room supply will be lesser and on coil db will be higher. and in case the return is ducted. room supply will be more and in coil db will be less

 

[mechbuild]

Walz, Thanks a lot. You have explained very well.