Room Temp. for IDF Room

jho_wel:

While I don't know much about IDF room ventilation, I think that you need to know more than the temperature of the supply air.

What about the treated fresh air supply rate?

How about the overall air change rate for the room?

Is there any "return air" or exhaust?

If so, at what rate/volume?

And, lastly,

What is the BTU rating of the FCU?

Hi jho-wel,

Please avoid using abbreviation here, what IDF stand for?

Anyway find if applicable on what you required.

Heat Load - the amount of heat generated is know as the heat load. Heat is measured in either British Thermal Units (BTU) or Killowatts (kW). 1 kW is equivalent to 3412BTUs.

The heat load depends on a number of factors, by taking into account those that apply in your circumtances and adding them together a reasonably accurate measure of of the total heat can be calculated.

Factors include:

The floor area of the room

The size and position of the window

The number of room occupants (if any)

The heat generated by equipment

The heat generated by lighting

Floor area

The amount of cooling required depends on the area of the room. to calculate the are in square meter

To get Room Area BTU = Length (m) x Width (m) x 337

Window Size and Position

If your room has no window then you can ignore this part of calculation, how ever as rule of thumb there are window you need to take and orientation into account.

South window BTU = south facing window Lenght (m) x Width (m) x 870

North window BTU= North facing window Lenght (m) x Width x 165

If there no blinds on the window multiply the results by 1.5

Add together all the BTUs for the window

Window(s) BTU = South window(s) BTU + North window (s) BTU

Occupants

You will have to take into account people who normally working in the space. the heat output is around 400 BTU per person.

Total Occupants BTU = Niumber of Accupants x 400

Equipment

Clearly most heat in the roo is generated by the equipment. this is trickier to calculate that you might think. the wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is probably safer to overestimate the wattage than underestimate it.

Equipment BTU = total wattage for all equipment x 3.5

Lighting

Take the total wattage of the lighting and multiply by 4.25

Lighting BTU = Total wattage for all lighting x 4.25

Kind regards

Roman

Can you please specifically mention what is IDF??? Is it Induced draft fan???. Do u want to provide air conditioning or only mechanical ventilation?? What application it is??/ Then the forum can guide you properly. Regards, Dr.M.Ramaswamy

I think he is referring IDF as in Intermediate Distribution Frame. Basically a term for a data closet or secondary server room.

Make sure that in your overall cooling solution you consider adaquate distribution of the air so that you don't have hot spots. If you are setting up new racks try to orient them for proper cooling also.

Here are a couple good sites.

http://www.42u.com/42u-rack-cooling.htm

http://www.openxtra.co.uk/articles/calculating-heat-load

Well done! GA from me.

This are the other Datas & information gathered:

Intermediate Distribution Frame (IDF) Rm./ Telecom Closet:

Room Size: 3800x2950x7150 Ht

with Door Louvre = 650x350 clear opening

No windows.

Fresh Air Grille is 28 lps ( treated from AHU ent. temp. 30.5db/21.5wb; leaving temp. 12.26db/11.9wb).

FCU ( 4.56 KW Total Cooling )

Supply Air = 260 lps (ent. temp. 24db/17.8wb; leaving temp. 13.0db/12.1wb)

Equipment Heat Dissipation is 33,884 BTU/hr

Lighting = 288 watts ( total)

Walls is 150 mm thk.

As per the general HVAC Engineering practice the air quantity calculated/selected should offset the room sensible and latent heat load. It should also handle the total sensible and latent heat loads i.e. including the outdoor (Fresh air for ventilation purpose). The air quaintly can be calculated using this formula Q da = ERSH/ (t rm- t adp) (1-BF) 60Xdensity of airXSP.heat of air Q da = Dehumidified air qty ERSH= Effective room sensible heat t rm = room design temp t adp = Apparatus dew point temp BF = By pass factor From your data it appears that the supply air is at and return air is which is normal. If you need specific inside conditions you have to calculate eh actual heat load using E20 or HVACOMP or any available software.