Displacement Ventilation

[kodzak1981]

Hi,

can anyone give me any guidance on how to design displacement ventilation system?

I am reading nowdays about it, and I see it is low velocity, with low temperature difference between supply and room air. But can any one just guide me what shall I calculate, how to determine ariflow rate? Is that the same way as normal ventilation?

What are steps for designing these systems?

Thanks in advance.

Regards

 

[chicopee]

Perhaps the words" displacement ventilation system" refer to forced ventilation system; I did not read what you read, so I don't known.

 

[kodzak1981]

Hi,

I am sorry for not being more precise. I am thinking on ventilation systems where air is supplied through the grilles located low in the wall or underfloor.

I haven't done so many HVAC system, only few systems where supply/extract diffusers are located at ceiling. So I calculate heat/cooling load, fresh air requirements, etc.. and air flow for specific room is highest of all demands.

What is the case with displacement, when air is supplied at floor level? There is some temperature gradient that needs to be considered, and how to get proper air flow for one room?

Thank you in advance

 

[DRWeig]

The April 2012 ASHRAE Journal has a good discussion and analysis of this in an article about IAQ in natatoriums.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[SAK9]

You are not going to learn to design displacement ventilation systems from a forum.You need to read the AHSRAE Displacement Design Guide and develop your own spread sheet for load and airflow estimation.Load factors need to be applied for lighting,solar load etc which were developed from a ASHRAE research project.
There is plenty of free information provided by diffuser manufacturers if you would care to google