diverting hot air

[stevedl]

Hello all,

I need to vent a computer cupboard and want to use the heat (approx 2.5kW) to heat a room. The heat would need to go outside once the room reaches temp. What's the best way to divert the hot air?

I thought about ducting from the top of the computer cupboard into a T junction with 1 fan blowing into the room and another blowing outside. I'd wire the fans to a thermostat in the room so that fan1 came on when the office needed heat and fan2 came on when it didn't (one of the fans would always be on & both would never be on at the same time). The flap vents would ensure that air was always pulled from the computer cupboard. See dodgy ascii drawing below.
[code:1]
--------------------------------------------------
room || {--x x--} || outside
---------------------- -----------------------
flap fan1 | ^ | fan2 flap
vent | ^ | vent
| ^ |
[/code:1]


Does this seem OK or is there a better way to do it? I did think about just having a single fan blowing into the T junction with adjustable vents to the room and outside but I imagine they would need fairly constant tweaking as the outside temp changed.

Cheers,

Steve.

 

[electronicsuk]

You could use a system similar to what you'd find in a zoned ducted A/C system, by way of an electrically controlled damper (either the louvred or butterfly valve type) and one fan. However, it would cost significantly more than your plan of using two fans, and the parts aren't available down at your local B&Q.

Another (expensive) option would be a heat recovery unit. Indoor extract air from server cupboard vented to outdoors via recovery unit, then another independant air supply vented back through the unit into the room(s) you wish to heat.

The extract and intake sides will have independent fans, so if you leave the extraction fan running 24/7 then you will always remove heated air from server cabinet, while the intake fan could be controlled via a stat to regulate room temperature. The only difference is that without the intake fan running, all hot air will be exhausted to outdoors rather than being transferred via the heat exchanged to warm the air on the intake side.

 

[stevedl]

The dampers or HRU seem to be exactly what I need. Unfortunately, the room I'm looking to heat is essentially a glorified shed so I'm pretty sure they would be too expensive. Was only looking to spend £100 or so.

Wonder if I can pick up a 3-way version of an electronically controlled damper second hand. Now I know the correct terms to search for I'll give google a try again.

Thanks for the help,

Steve.