Need help improving WaterChiller...

[Karatekid]

Hi Guys,

Last week disaster struck me.
Currently I'm using a 186W phase-change waterchiller, chilling coolant in a 9 litre (2.4 gallon) reservoir.
Here's what it looks like:
http://members.home.nl/jan.barelds/Karatekid's_System/Full-size_Pics/Coolunit.JPG

Anyway, the reservoir started leaking while I was away, and when I came back, the entire room was flooded.
9L of coolant is a LOT when it's not in the right place, I can tell ya.
However, this does give me the oppertunity to improve it's performance by resizing the reservoir. Coolant temps are @ ~ 8 'C (14 'F) below ambient without the PC on, and climb to about ambient after a long night of gaming.
I have a feeling the coolants temps would decrease if I were to use, say, a 1 Litre (0.26 gallon). But what would the negative effect be? I guess the coolant would warm up a lot faster, but would it only warm up to the same levels (about ambient)?

Experts, plz help me out...

[bowman1964]

well for one ,it wont make much noticeable differance cooling 2 liters or say 6 liters.
the evaperator will only cool to a certain temp.what ever it is preset too.
the differance will be how long it will take to drop the coolant to say 14f temp.
2 liters may only take 20 minutes while 6 liters might take 1 hour.
now the up side to using more coolant is ,it will take longer for the temp to warm up.
the smaller resivour (say 2 liter ) will warm up much faster.
in the end the chiller will still only get the coolant to the same temps.not making much differance in how low it will go ,but in how long it takes to get there.
the only way to lower your temp is to change something in the chiller itself like,change the refridgerant charge.or lower the thermostat if it has one?something alone those lines.;)

[Bartje]

I don`t agree to Bowman..

Take any phase change cooler to the swimming pool.. You won`t be able to degreese the water inside the swimming pool by 1C, not in a year..

Take 1L out of the swimming pool and cool with the same phase change cooler and you'll propably be able to cool to zub zero temps..

Why because a swimming pool looses all the cool temps to the ambient where the 1L looses temp also, but way less than a swimming pool..

That why i think it should really make a difference in your chiller...
But degreesing the volume of the reservoir would sertainly add to the speed the liquid is getting warm.. So instead of 30min before water is at ambient temp, it would be more like 10mins before you get there...

I think the chiller just aint strong enough...

[bowman1964]

Originally posted by Bartje
I don`t agree to Bowman..

Take any phase change cooler to the swimming pool.. You won`t be able to degreese the water inside the swimming pool by 1C, not in a year..

Take 1L out of the swimming pool and cool with the same phase change cooler and you'll propably be able to cool to zub zero temps..

Why because a swimming pool looses all the cool temps to the ambient where the 1L looses temp also, but way less than a swimming pool..

That why i think it should really make a difference in your chiller...
But degreesing the volume of the reservoir would sertainly add to the speed the liquid is getting warm.. So instead of 30min before water is at ambient temp, it would be more like 10mins before you get there...

I think the chiller just aint strong enough...
well we are not talking about a large amount of uninsulated water.
we are talking about a well insulated chiller box.

i do agree with you on what you are saying but....................
i have done excatly what he is tring to do.and if you have a insulated container so you dont lose any temps from heat absorbed from a outside source.you will not see much of a noticeable differance in temps going from 4 liters to 2 liters.maybe 1 degree if you are lucky.
it all has to do with how much heat the coolant is absorbing from the chiller tank.
now if we had a uninsulated tank and increased the amount of coolant...yes you will see a big differance from the extra surface area being wetted by the coolant.more surface area more heat absorbed.
but in a small chiller tank that is very well insulated you wont see much of a differance.
i went from 2 liters to 3 liters in my chiller.and gained no more temp increase..
but mine is very well insulated.;)

[Karatekid]

I am planning on insulating the smaller container very well, just like the 9 L one I use now (if I do decide on resizing it...)

I think Bowman has a point here. Going from a 9 litre container to a 2 litre one, won't do much for the temps, as relatively a small amout of coolant comes into contact with the (well insulated) container (in both cases).

It's just the phase-change unit itself. I guess 1/4 hp is just too small for a waterchiller. Better luck next time. I've had lots of fun building it though, and the learning experience is priceless :)

[bowman1964]

who told you 1/4 hp was too small?man that is just right.should easily chill coolant down to -20c or so.
might be low in charge or it has a temp control somewhere you will need to bypass.
i have a 1/3hp cooling a cpu evaporator (like a prometia) and running a chiller with 3 liters of coolant.and the chiller will go down to -27c and almost stay there at full load.cooling a 80 watt pelt on my r9700 gpu and still cool the chipset and memory.

so just take your time and 1/4 is a plenty fine.to just use as a chiller:)

[Karatekid]

Bowman,

Problem is, I can't find any specs on this thing anymore. They were on a tag in the housing of the mini-fridge, but I didn't care preserving it. I know, I should be kicked in the nuts. If I had the agility, I'd do so myself :)

What I do know is:
I took care of the thermostat, switched it with another one. (running full-time now.)
The unit is charged with R12
Cooling capacity is rated at 186W or 1/4 hp.
There are no fittings for filling / refilling to be found.

Because of the R12 being used, I knew I had to be carefull with it not to break any lines. So I left it the way it was, and just built a container around the evaporative coil.

I don't know what I'm doing wrong here, but it must be terribly wrong considdering the temperatures you're mentioning, Bowman...