Water cooling project

[Nuno_pt]

I'm trying to figure out how to dissipate about 1700W of constant heat from some copper plate.

I've two copper plates of 300x300x12mm with water channels inside they are solder to each other, with an IN and OUT G1/4 holes.

I've here two PC pumps, one with 600L/h and another with 1500L/h debit, let's say that the water IN is tap water from a reservoir with a temp of 20ºC (room temp), and the water OUT would be limited to 50ºC, so we've a span of 30ºC that the water can be heated by the 1700W dissipate to the copper plates.

What system would be necessary to cool this 30ºC on the radiators, and what quantity of water in the reservoir would be needed for this.

I've been looking at CPU cooling systems but can't get an idea on how to get read of this heat. 

What I got so far is this:

Temp of water IN (Tin) = 20ºC
Temp of water OUT (Tout) = 50ºC
Heat capacity of water = 4.18 kJ/kg-C
Flow rate = 0.16L/s or 0.416L/s (depending of the pump use)

Any thoughts on what PC radiator to use.

Thanks.

[CM800]

I'd suggest buying one of the radiators and testing them, or at least trying to find someone who has done that.

It is unfortunate that the manufacturers don't give a nice datasheet... I know I would.

[Marco]

Any thoughts on what PC radiator to use.

This old website has some useful numbers, it would seem a tripple would get you the 30 degree delta relatively easily, but a double would be cutting it close.

[Jeroen3]

Temp of water IN (Tin) = 20ºC
Temp of water OUT (Tout) = 50ºC
Heat capacity of water = 4.18 kJ/kg-C
Flow rate = 0.16L/s or 0.416L/s (depending of the pump use)

Except the input water won't be 20C when it's on for a few minutes. Typical cold temperature of water systems is 60C, because radiators work best when the difference with the environment is high.

Don't forget that you also need pressure, 0.4 Liter per second is a more then 0.05-0.10 liter per second typically found in pc's.

[Nuno_pt]

So would this be an impossible task with PC cooling radiators?

I know that if the water start at 20ºC (room temp) after a few minutes running on the system with will be higher but not much higher if the radiator have the capacity to cool the water you could have a delta of 10 or 20ºC between the Tin and Tout.

The only thing here is what type of radiator is capable of dissipate that heat, to have that delta on the water.

[CJay]

Gut feeling is that PC watercooling systems aren't designed to deal with anything like that amount of heat however you might be able to find a motorcycle radiator that will.

This looks interesting though:

https://www.smcworld.com/temperature_controller/en/pdf/series/HRS_en.pdf

[Nuno_pt]

Hi CJay,

Nice to see your Call.

There are some guys using the PC radiators to cool this, but not in 100% duty cycle, like I'm going.

This is to cool two LDMOS that will generate 1700W of heat on the copper plate, so this heat will have to be remove.

You can have a look at R3KBO (eb104.ru) on youtube, OZ1BXM, OZ1CT.

[Marco]

PC radiators are also designed for far smaller deltas and designed to take convenient fans, unlike automotive ones.

With the loudest fans the larger ones are measured at a couple degrees at 500W at the website I linked. A 4x120mm cooler should handle it no problem AFAICS.

[CJay]

Hi CJay,

Nice to see your Call.

There are some guys using the PC radiators to cool this, but not in 100% duty cycle, like I'm going.

This is to cool two LDMOS that will generate 1700W of heat on the copper plate, so this heat will have to be remove.

You can have a look at R3KBO (eb104.ru) on youtube, OZ1BXM, OZ1CT.

Heh, I've seen those EB104 designs before and have a set of VRF2933 devices stored safely away with ferrites and a hardcopy of the plans for some day when I have an advanced licence, at the moment with my M6 I daren't even take them out of storage for fear of making more than 10W...

[Nuno_pt]

Yeah, that 10W in the UK  , but it's not only there  there are a few other country's in EU that are the same.
Here the low is 100W.

[jmelson]

So would this be an impossible task with PC cooling radiators?

1700 W?  PC CPU radiators?  Hah, no WAY!  You are looking at something half the size of a CAR radiator!  You might be able to pick up an automobile heater core at a scrap yard, or the condenser or evaporator core out of a wrecked window air conditioner.  Those  might be about the right size.

Jon

[Marco]

Early large PC watercoolers simply put 9x120 fans on a car radiator. A quad PC cooler IS pretty much half a car radiator ... just with convenient fan mounts.