[PLUG-TALK] Another use for 12 volt fans?

[Keith Lofstrom]

On Thu, Sep 21, 2017 at 05:06:59PM -0700, Tomas Kuchta wrote:
> Relying on this kind of active solution for safety inside a wall build to
> outlast you seems like - what could possibly go wrong!
> 
> I suggest looking for passive systems such as radiation, separation,
> chimney effect, heat resistant materials, etc. Or getting less heat of your
> fireplace.

Tomas raises good points, but ...

> In case you persist, USB power source or wall wart is more than enough to
> supply less than 0.5A for these fans. Maybe, you do not even want them
> spinning at max speeds/voltage/current.

Not so.

USB maximum power levels (5 volts 5 amps?) are suitable
for toys and small objects, not moving air around a
house or even a room.  That requires more than 25 watts,
probably more than the 40 watts I'd be comfortable
supplying from a fan-cooled 60 watt (12 volt 5 amp) supply.
Enough fans to blow enough heat past a fire sounds like
a lot of watts to me.  Wall warts and charger bricks are
temporary - I have plenty of dead ones as evidence.

I use my Noctua fans as supplemental cooling for the 32
port gigabit switch for the house; it ran hot (seemingly
by design), but electronics last longer if kept cool.
The original fan in the switch failed, probably due to
overheating, which is why I got the used switch cheap ...

-----

But I concur with Tomas's major point.  Ultimately, while
I like hacker endeavors, there are reasons why we purchase
spendy HVAC solutions;  they can fail and kill people. 

A month ago, I was staying at a friend's house in Salt
Lake City, when the electronics caught fire in his
furnace.  We spent part of the night waiting across
the street while the fire department stopped the fire,
disabled the furnace, and blew the toxic smoke out of
the house.  For calling the fire department when the
poorly-designed furnace was about to explode, he was
evicted.  Better that, rather than incinerated by a
landlord's bad maintenance and equipment choices.

Keith

-- 
Keith Lofstrom          keithl at keithl.com