Closet cooling and fan static pressure

[kaspor]

Hello

I have a closet which is approx 2.7m high by 1m deep by 1.2m wide. I have l equipment in there that needs to sit at max 30degC. There are two double doors on the closet.

In order to keep it at 30degC I’ve installed 4 extraction fans on a thermostat. The fans draw air in through gaps in the doors and from underneath and exhaust it at the top. The fans are similar to these

S Series 100 Wall/Ceiling Exhaust Fan – White - Universal Fans

The Fanco S Series exhaust fan is a small yet capable fan. It features a simple design and can be mounted on the ceiling or wall. It can also be connected to duct so the air may be exhausted out of the house.

universalfans.com.au

The problem is the noise. They’re generation 30dba each. I’ve insulated them as much as I can but they’re still loud.

So I then started looking at quieter fans such as these

NF-S12A FLX

The NF-S12A marks the third generation of Noctua’s signature S12 series quiet case fans, which have received more than 250 awards and recommendations from the international press. Featuring a further refined blade design with Anti-Stall Knobs that works in tandem with the new AAO (Advanced...

noctua.at

They have a much lower db but looking at the performance curve it looks to have a much lower static pressure rating

NF-A12x25: performance comparison to NF-F12 and NF-S12A

Designed in Austria, Noctua's premium cooling components are renowned for their superb quietness, exceptional performance and thoroughgoing quality.

noctua.at

Does this mean they will inherently take longer to get the temp in the closet down as they are not able to draw the same amount of air in?

I’m worried that if I change the fans over that the newer fans will be useless as they won’t be able to draw air in like my current ones.

Also cutting holes or vents for intake isn’t an option unfortunately.

 

[HVAC-Novice]

Thanks for the reply. Power ratings would probably an inaccurate way to do a heat load calc as much of this equipment is sitting well below its full capacity. I can measure the power draw, but the whole closet is probably drawing no more than 1.2kW (electrical)

What are you running in your HOME? Are you crypto mining, or what?

If it draws 1.2kW, it dissipates 1.2kW (minus what dissipates in the spaces if you have PoE)

imagine running a 1kW space heater all year, that closet would be extremely hot. I doubt you actually draw 1.2 kW. But I don't know what is going on....

 

[3DDave]

Where you live may not make some legal distinction, but physics says that connection would make a chimney to route smoke and fire through the flooring and will accelerate the ability to die if a fire breaks out either in the closet or in the area under the closet.

Frankly, your wife should be more concerned about the problem of creating a smoke stack than a bit of humming sound.

Adding forced ventilation to add more draw to a fire below the floor makes it far worse - it will be distributing carbon monoxide.

The one who commented about "air registers" is an air head. Those are typically attached to closed ductwork that prevent movement of fire from one area to another, mainly by not supporting combustion in the ductwork.

 

[kaspor]

What are you running in your HOME? Are you crypto mining, or what?

If it draws 1.2kW, it dissipates 1.2kW (minus what dissipates in the spaces if you have PoE)

imagine running a 1kW space heater all year, that closet would be extremely hot. I doubt you actually draw 1.2 kW. But I don't know what is going on....

Yeah a poor guess on my part. I went and measured it. Getting around 150W at the moment.

Where you live may not make some legal distinction, but physics says that connection would make a chimney to route smoke and fire through the flooring and will accelerate the ability to die if a fire breaks out either in the closet or in the area under the closet.

Frankly, your wife should be more concerned about the problem of creating a smoke stack than a bit of humming sound.

Adding forced ventilation to add more draw to a fire below the floor makes it far worse - it will be distributing carbon monoxide.

The one who commented about "air registers" is an air head. Those are typically attached to closed ductwork that prevent movement of fire from one area to another, mainly by not supporting combustion in the ductwork.

Ok I see your point and appreciate the feedback, but the likelyhood of a PC or an NVR catching fire is extremely low. I am not running a data center here lol. I have been in the electrical and construction business for 40 years and tbh I have never seen this happen. And even if they did catch fire, the abutting bedrooms are more of a concern than the floor below which is a hallway. That's why the law here mandates safety switches (residual current devices) on all mains power + smoke detectors throughout the home which are interlinked. Plus the amount of internal protection on modern electronics would also add another barrier to this happening. There also holes in the subfloor for all types of services. HVAC risers, water, sewer and vent stacks. If this were a real concern, then we'd be fire sealing these penetrations too. Granted this is mandatory when we build data centers, apartment complexes or substations (and the like!).