Heatercore Efficiency?

I see so many ways of testing waterblocks, like CW. Why aren't the same ideas applied to heatercores/radiators. I know the rule of thumb is bigger is better (if space allows) but what about for heat dissapation. I was thinking that C/W could be used, but I cannot assume how well it will measure since the heat of the inlet water is determine by how efficiently the waterblock transfers heats. I know there is probably something out there I don't know. What would you guys use to test how efficiently a heatercore dissipates heat.

As a rule of thumb, any thermal testing done in a regular PC is bogus. Unfortunately due to convenience and ease, this is where a lot of rules of thumb come from.

Real testing that can divulge much more accurate and meaningful results is done in bench testing. Due to the factors that affect heatercore/radiator performance, it would be extremely difficult (impossible) to get any meaningful information from a regular PC that could be extrapolated into other useful information.

Lucky for us, when Bill Adams was still an independent member of the forums (before a company finally wised up and started paying him) he did some work on heatercore and radiator efficiency. This is what he learned:

Radiator Heat Dissipation Testing

Note that some of the graphs in his original article are incorrect, and he has an accompanying revised version of the graphs here:

Corrected Radiator Dissipation Charts

This thread could possibly become very useful for a lot of people if you want to take a certain direction from here. Read over the article and ask about anything you don't understand. A lot of it is fairly complicated, but there is a lot of information to be had from the article. Honestly, I probably still don't understand every bit of it and I've read through it more times than I can remember.

Also much depends on how much space you have for rad.
The best "small" rad I've seen is probably Lada heatercore, it's n size of Chevete heatercore, but performing a little better.

Of course car / monster clima radiator would perform better, but the question is cost and if it will fit.

This

Q = Ww Cp (T – Ti)
where Q = total heat transferred, Btu/sec

Ww = coolant flow rate, lb/sec

Cp = specific heat of coolant, Btu/lb°F

T = exit temperature of coolant, °F

Ti = initial temperature of coolant, °F

Click to expand...

This is exactly what I was looking for .

But how would using this and the C/W of a waterblock (combind with ambient temperatures) simulate the CPU temperature at "X" watts? I'm trying to come up with a advanced formula, I'm trying to write it on paper and figure it out. BTW thanks for the linkage. Anyone have some suggestion.

For what it's worth, unless you have some "super" water block, the radiator will most likely have much more capacity than most water blocks can handle. As for overall system C/W performance, a small improvement to the water block is readily measured. On the other hand, an improvement in radiator size will only have a small increase in performance. The water block (with a good pump) is the key to the biggest gains in temp reduction. Good luck.

KK

PS: A big flow increase to radiator fan air flow falls somewhere in between if you can deal with the noise.

May I ask what you would like these equations for?

If you are looking for a decent way to estimate system performance mathematically it is next to impossible to quantify appropriately, and plain impossible to quantify correctly.

I have a slightly related question - many websites advertise radiators as having a specific "BTU" rating - what does this number quantify? Does it have any bearing on real-life performance with fans strapped onto it?

Can the same radiator be assigned a different "BTU" rating given two different test environments?

Thanks.

I just want a way to actually compare radiators/heatercores. That way people don't say "the bigger the better."

This can usually be decided subjectively - trying to find an objective solution to comparing radiators or heatercores is likely a lot of expended energy without much benefit.

I reccomend you attempt to rate the most important characteristics of heatercores and radiators, and then rate each heatercore you are comparing in these categories. This should require less effort, you will be more successful, and your answers will mean more and be easier to come to.

I was thinking about how to measure the 'effeiency' of a rad/heatercore and came up with a relitively simple idea.

Run your Setup like this

Pump - CPU Block - Inline thermal Probe (Temp IN) - Rad/HC - Inline thermal Probe (Temp OUT) - Back to pump

Best to use on of the constant heat outputters for the cpu. compare the delta of temp in and temp out of different rads/hc's and see what you get.

BTU performance for a radiator is affected by (3) factors;

- incoming temperature difference (ITD) between hot liquid and cooler air
- liquid flow rate
- air flow rate

An increase of any of these will increase BTU amount, ITD is the more important factor, air flow is second, and liquid flow is third. If a radiator maker does not disclose these (3) values, then they are not being fully honest if they quote a generic BTU rating. It is quite complicated to calculate directly, but if they do offer performance curves at different flows and reference the operating temperatures, then you have a valid means of comparison. Good luck.

KK

ToolBox said:

I just want a way to actually compare radiators/heatercores. That way people don't say "the bigger the better."

Click to expand...

Well, that's still true, bigger is better. The thing is, there's usually a few limiting factors, like cost, and space.

A 6" by 6" Chevette core is your basic rad, and it'll outperform pretty much anything else you can find, except for a bigger core.

Either way, the most important thing to remember, is that airflow is really critical, so if you're going to focus on one part, I'd suggest that you direct your attention to that one.

You already know what I think...

BigBen2k -> What is that thing?

BB you and your squirrl cage blowers. Hmmphhh mine got screwed up when I was wiring it, going back to regular fans...

ILikeMy240sx said:

BigBen2k -> What is that thing?

Click to expand...

It's the fan that accompanies a heatercore, in a car. Better known as a "squirrel cage" blower.

I'm more than half way through shrouding it.