External Rad at Window

Dirk Diggler · 25 Sep 2017 at 13:14

What's the consensus with external radiators at an open window, should they suck the cool air in or blow the hot air out? Would intake of cold air risk condensation?

Edit: this thread lead to me installing an external radiator in my garage, here's how it took shape...

First, it's some hammer action with the battery drill. I decided to forget the blank plates and just route from inside the right hand storage cupboard. I routed 2 hoses and also a signal cable for the PWM control of the fans.

Next, I bought some shelves from Homebase, a bargain at £20 IMO.

Now I've set the PC up so that I can remove the external rad and link the flow and return, so that I've got a stand alone PC should I need to move it to another room. I've also set the top rad in the case to ramp it's fans up should the rad in the garage fail to cool for any reason (PSU trip or whatever).

I then stuck some swivel 90 fittings on and connected up the external hoses.

Now, I hook the hoses up to the external radiator. I've made it so that I can easily disconnect at the radiator and drain if I need to, and I've stuck a 600w EVGA PSU in there to power the 4 fans.

All up and running, so on to some tweaking for temperature etc..

Afterwards, I decided to fit a little bypass and then mount the radiator properly.

Next, I boxed it all in and applied some insulation to make it snug. I've installed an anti-condensation heater and a frost stat.

Finally, I've installed a little flap on top that will keep the heat in if it's Brrr.. and this will lift up automatically to let the hot air out when the fans ramp up to 100% when gaming.

Now I just need to monitor the numbers and tweak accordingly. My OCD is now at bay.

VKleita · 25 Sep 2017 at 13:30

Hey String !

I did this very fact about 12 months ago (Admittedly Pastymuncher did a far better job of it than me)

My external rad is a 4 x 200 MM fan unit, (Mo Ra3 - 420 LT) I have the bottom fans sucking in and top fans blowing out (reason I ended up doing this was with all sucking in I found the room just got too hot!)

I have it seated up as close to window as poss to try to drag in outside cool air.

I have never had ANY issues with condensation or any such thing even when it was icy purely due to the heat from the corridor under the room warming up everything.

One of the biggest issues I found was actually getting the office door to seal properly other wise my other half would know when the window was open due to drafts!

I'll see if i can get you a couple of piccies later if you wish.

Dirk Diggler · 25 Sep 2017 at 14:42

VKleita said:
I'll see if i can get you a couple of piccies later if you wish.

Yes, that would be good, cheers.

I've rearranged everything because whilst my loop is nice and cool, my room was almost 30C with the heat after a good gaming sesh. It sounds like I need to go with air pushing out towards the window.

pastymuncher · 25 Sep 2017 at 19:16

My rads are mounted on the landing windowsill inside a filtered box and suck the colder air from outside through them. I get water temps in single figures during the winter (no I don't get condensation issues, don't know why, just never have) and Summer water temps are usually no more than a degree or two more than outside temps. I have no problem with where the air goes due to it being outside my computer room but to be honest the warm air isn't that warm anyway due to the outside air being cooler than inside plus the window is open anyway. The whole point of going watercooling and setting it up the way I have was to get the hot air out of my computer room in the first place. My room is just a pair of cupboards with the seperating wall taken out and one of the doorways removed and plasterboarded over. It's small at 5x6 feet but is plenty big enough for my needs plus my setup is out of the way. When I first made the decision to go watercooling I had SLI 6800GT's with a overclocked socket 754 Athlon 64 3700+ (later a socket 939 4000+ and SLI 7800GT's) before switching to Intel when Core2Duo launched and it used to get very toasty in here which is why I stuck the radiators in a box on the windowsill.

Dirk Diggler · 25 Sep 2017 at 20:45

@pastymuncher interesting setup.

My cave is actually an office and backs on to my garage which is integral to the house, so a brick wall separates the two rooms. I was toying with the idea of drilling a hole for the tubes to go through and then mounting the radiator in the garage, but I thought the Glasgow winter would see the fluid getting so cold that I would risk condensation inside the PC.

Maybe I could configure the pump to go to minimum flow when the water temperature gets really low?

VKleita · 26 Sep 2017 at 09:01

If its a garage , with other devices in there (fridge freezer etc) I wouldn't expect it to ever go lower than singles at very best.

So basically similar to what Pasty is getting.

@pastymuncher is any part of your house dehumidified or anything? that of course lowers the dew point.

VKleita · 26 Sep 2017 at 09:01

No piccies so far im afraid been bit hell on earth here.

pastymuncher · 26 Sep 2017 at 09:11

Nothing dehumidified in the house. It just works.

String said:
@pastymuncher interesting setup.

My cave is actually an office and backs on to my garage which is integral to the house, so a brick wall separates the two rooms. I was toying with the idea of drilling a hole for the tubes to go through and then mounting the radiator in the garage, but I thought the Glasgow winter would see the fluid getting so cold that I would risk condensation inside the PC.

Maybe I could configure the pump to go to minimum flow when the water temperature gets really low?

Have you seen where I live? It get's colder here than Glasgow. Back in 2010 I think it was we had outside temps of -18 degrees C during the day and even with the windows open just a crack I was getting water temps down to 4 degrees C and still had no problems. I would have a go at sticking it in your garage, you never know it mat work and you will wonder why you didn't do it before. You will need three holes in the wall, 1 each for inlet/outlet and another for the fan wiring. I made up a load of fan extension cables so I could still run them off my fan controller. I use 12mm copper pipe between the pc and rad box as I found that Mayhems 10/16mm tubing fits nicely over the copper pipe with a bit of persuasion. Previously I used 15mm copper pipe but had to use a step down at each end to be able to join the tubing to it and it wasn't very tidy.

VKleita · 26 Sep 2017 at 09:28

Im guessing it is the run back that means it raises the coolant temp just enough to avoid condensation.

When I set up mine everyone was like "ooo condensation your pc be dead in three months" even leaving window wide open in middle of winter room temp has never gone below 7 and I have never seen any condensation even with the unit off.

<shrugs>

Dirk Diggler · 26 Sep 2017 at 09:38

pastymuncher said:
You will need three holes in the wall, 1 each for inlet/outlet and another for the fan wiring.

I'm thinking of putting a metal face-plate on the wall (like a socket but blank) and drilling two holes to accept bulkhead fittings. I can then simply screw the tubing from the PC on to the face plate, which would allow me to repeat in reverse if I had to remove the PC for maintenance etc.. I could also mount a brush face plate next to it for the cables.

VKleita · 26 Sep 2017 at 11:16

Be careful of using them brush faceplates, I find that air passes through them if there is a draft, and if your garage is sub zero .. might get a little chilly

Then again that might be a good thing by the sound of it!

I went with Koollance fittings next to the pc.

Example:
https://www.overclockers.co.uk/kool...male-threaded-g-1-4-bspp-black-wc-143-ka.html

I used the ones with built in 16/10 ends so I didn't need any extra connectors etc, OcUk don't seem to stock them thou.

Hope that gives you some ideas at least!

Schizo · 26 Sep 2017 at 11:22

Didn't someone on here put some copper tubing in a water butt outside his Window?

Dirk Diggler · 26 Sep 2017 at 11:24

@VKleita to keep things sealed I could use a simple flex outlet face plate. I'll need to do a bit of planning here, but definitely think the rad in the garage would be a big improvement and worth the effort.

VKleita · 26 Sep 2017 at 12:15

I'm looking Forward to this!

Dirk Diggler · 26 Sep 2017 at 15:13

Yea, I'll take some photos as I go and keep you updated, although it's a month away before I start the cave/office refurb project.

Here's a couple of pictures of how it is just now, with the rad pointing to the open window for some hot air exhaust action.

Dirk Diggler · 2 Oct 2017 at 06:26

What's the temperature Delta for condensation to form if the assumption is air inside the PC is at 25C? I've been Googling but not getting anywhere. I assume the volume of water in the system would be a factor also?

VKleita · 2 Oct 2017 at 11:17

Good question ... No idea

Sorry!

All I can tell you is as an experiment we hung my rad out the window (Don't ask)
the external temp was like 9 'c I never received any condensation on the tubes leading back to pc or inside on the blocks etc.

pastymuncher · 2 Oct 2017 at 12:56

Same here. I have had my water temp down to 4 degrees C with a external temp of -18 degrees C and still didn't have any condensation anywhere in the loop. It just works.

samcat · 2 Oct 2017 at 15:09

String said:
What's the temperature Delta for condensation to form if the assumption is air inside the PC is at 25C? I've been Googling but not getting anywhere. I assume the volume of water in the system would be a factor also?

What you need to do is look up the dew point, its a factor of humidity and temperature.

Typical UK humidity varies, but 70% is a reasonable figure. Sometimes in your home it can be lower.

http://www.calculator.net/dew-point...t=&dewpointunit=celsius&humidity=75&x=54&y=15

VKleita · 2 Oct 2017 at 15:28

Hmm interesting, if external temp is 5'c but room air temp is 25'c humidity is 70% then Dew point is considered 19'c

So in theory any metal surface colder than 19'c should see condensation. Which i certainly did not see.

Or do we take the original air temp (5'c) and use that for the Internal dew point also? (Which would be Zero)

My head hurts