Temperature measurement

[pHaestus]

Jaydee:

Normally I'd have some choice words for the importance of statistical significance and the central role of error bars in any honest testing. Luckily for you though there's now a waterblock testing alliance! And undoubtedly Ben will drop in soon to tell you that "it's ok there's nothing to worry about! There's plenty of room for fluff reviews and "good enough is good enough".

Hooray!

Truth is you have to be mentally off kilter to spend thousands of dollars to test $40 waterblocks. I've cobbled together an almost acceptable test rig for a few hundred, and it's a pain to use. But I enjoy going downstairs and fiddling with it and making my little at home heat transfer discoveries. It will be really satisfying to have it all come together and post a new waterbock comparison article here on Procooling. Would you honestly be satisfied if that article DIDNT include a pressure drop vs flow rate chart? Or a C/W vs flow rate comparison for all blocks? The readers of this site are sophisticated enough to deal with that I think. Now the statistics behind whether a line running through points on a graph is meaningful or complete bullshit may be a bit too much for the average reader of this site. That doesn't make it any less important a question though...

[Since87]

Originally posted by bigben2k
But you're right about one thing: I really ought to take the time to figure out what kind of delta T I'm aiming for, in that block coolant temp. Last I checked, it was less than 0.5 deg C, and can go down as low as 0.1 deg C, with a low flow rate.

'High' not "low", and what the dT can get down to depends on how restictive the block is.

[jaydee]

Originally posted by pHaestus
Jaydee:

Normally I'd have some choice words for the importance of statistical significance and the central role of error bars in any honest testing. Luckily for you though there's now a waterblock testing alliance! And undoubtedly Ben will drop in soon to tell you that "it's ok there's nothing to worry about! There's plenty of room for fluff reviews and "good enough is good enough".

Hooray!

I have already heard them and somewhat understand them, but still have yet to see any real evidence it is usefull to the average Joe.

Truth is you have to be mentally off kilter to spend thousands of dollars to test $40 waterblocks. I've cobbled together an almost acceptable test rig for a few hundred, and it's a pain to use. But I enjoy going downstairs and fiddling with it and making my little at home heat transfer discoveries. It will be really satisfying to have it all come together and post a new waterbock comparison article here on Procooling. Would you honestly be satisfied if that article DIDNT include a pressure drop vs flow rate chart? Or a C/W vs flow rate comparison for all blocks? The readers of this site are sophisticated enough to deal with that I think. Now the statistics behind whether a line running through points on a graph is meaningful or complete bullshit may be a bit too much for the average reader of this site. That doesn't make it any less important a question though... [/b]

Your refering to procooling.com and I am not. I "guess" I would expect those things to be in the review here as maybe 2-5% (that percentage unfortuantly doesn't seem to be rising, but falling) of the people on this site might be able to use those numbers to their advantage (if they actually do is another subject) and especially being we are more anal about things here. But I am not talking just about procooling.com. I am talking about my own site and the hundreds of other tech sites that do not have readers and never will have readers to the same level as a few here are. I see consistantly on many sites where readers get pissed off at how anal some are about testing. They don't want all this tech lingo and graphs. They just want to be told this is better than that and have a temp number from your test to show it. I feel this will never change as there is no other product in the world that has accomplished this even the one's with standards tagged on them like "UL" and "SAE" ect...


Maybe I am just not sure what "good enough" is anymore. If I can say with some reasonable certainty that block A is better than Block B on my system then I think I can live with that. I really don't see (yet) how the C/W value on my test system is going to be usefull for anyone being it will be impossible to replicate that C/W value on any other system (especially now that you say proffesional labs can't even do it with $100,000 equipment!). So I don't really grasp why it is important. Seems to me a temp number would be just as usefull and more easily understood to the average reader. Hell most people don't understand a lower C/W is better than a higher one!

But you say you have only got a few hundred into your system and you feel your capable of doing these measurments? If that is the case I will have to re-read your articles again and try and emulate your setup as I can handle a few hundred $'s! Ben is talking about what $9,000 just for temp monitoring? All I can say is **** that, I got better things to piss money away on strip clubs included!

I have been pondering what is good enough for a bout a year now when trying to put together my test bench, but I have yet to decide where I need to stop thinking and when to start doing. And if I start doing will it be good enough.

Bah, back to work....

[bigben2k]

This is exactly why I've been struggling with this issue of comparative, versus analytical testing.

In comparative testing, your only goal is establish which block is better, and its your total margins of error that's going to define your ability to do that. Otherwise, you just have to make sure that your testing conditions are similar, and as pHaestus pointed out, your results are going to fall within a range, which is best expressed using error bars.

In plain words, you'll only be able to tell that one block is better than the other if these error bars don't overlap. The more accurate you test, the shorter the error bar is going to be.

[edit: rambling removed]


Since87: thanks for the correction (fixed) (I hope that the meaning was still understood!) Nice catch!

[gone_fishin]

Originally posted by jaydee116
I don't know....

What I am not sure about is why we need to make such an analytical approch to this. Do we really have to know what the block does through out various flow rates? Do we really need to know the Base plate temp? Do we really need to try and measure inlet/outlet temps?

I just want to tell of block A is better than block B on my test bench with in a resonable amount of error. I was planing to sort blocks by groups. Group A would fit into high performance, Group B in middle performace, Group C low performance, and Group D not worth the metal used to make it.

Do I really need .01 accuracy to do this? Seems to me this is all the readers want. I don't think they want to hear all the flow rates, pressure drops, blah blah blah... They just want to know what level the block is in. If it is worth their money or not and how wrong they might go if they buy something else. Remember most consumers don't know jack about what they are buying, they just want to be told how good it is without a lot of technical mumbo jumbo they not only can't understand but do not want to understand, and quite frankly shouldn't have to understand. They got better things to do as they should.

I don't know.....

That's right, you don't know. You will never get any grasp of performance unless it is done at various flowrates. One point on a graph seems to be all you need. Without resolution and accuracy your one plotted point now becomes a big blob on the chart, get the picture? So my question to you is, why bother testing at all if you are going to do it that way? How could you tell a customer what is better if you don't have a way of knowing? Just tell them anything I guess and back it up with a half assed tinkertoy test setup?

Sorry to come off harsh but you seem to be trying to cater to the masses, people are already doing that without any testing at all.

[jaydee]

Originally posted by gone_fishin
That's right, you don't know. You will never get any grasp of performance unless it is done at various flowrates. One point on a graph seems to be all you need. Without resolution and accuracy your one plotted point now becomes a big blob on the chart, get the picture? So my question to you is, why bother testing at all if you are going to do it that way? How could you tell a customer what is better if you don't have a way of knowing? Just tell them anything I guess and back it up with a half assed tinkertoy test setup?

Sorry to come off harsh but you seem to be trying to cater to the masses, people are already doing that without any testing at all.

Cater to the masses yes, as there is no point otherwise. :shrug: I sure the hell will not go through all this just to tell the 5 people I know that can do something with good results my results.

If I test 5 blocks, a, b, c, d, e, and on my system d performs the best on my die sim at whatever flow rate I am using then how is that not telling him what the better block is? All he has to do is try and match my flow rate. Even if we used multiple flow rates and made a chart they will STILL have to try and match a flow rate so why give them more options than they know what to do with?

[pHaestus]

Just weigh them Jaydee. Heaviest waterblock wins

[gone_fishin]

Originally posted by jaydee116
Cater to the masses yes, as there is no point otherwise. :shrug: I sure the hell will not go through all this just to tell the 5 people I know that can do something with good results my results.

If I test 5 blocks, a, b, c, d, e, and on my system d performs the best on my die sim at whatever flow rate I am using then how is that not telling him what the better block is? All he has to do is try and match my flow rate. Even if we used multiple flow rates and made a chart they will STILL have to try and match a flow rate so why give them more options than they know what to do with?

I did not express the masses part of my anal ravings very good. I was allluding to giving in to what the masses want as far as a test goes (they do not know what is required so why give in). As you well know, a blocks performance curve is not linear in respect to flow rate. Someone could easily skew a test to the dumb masses by running a really low flow for a block that is designed for a higher water presure. A set of flow rate points establishes a curve that one can see the direction performance is heading on either end. A really well block could be made to look like it is only slightly better than the pack with only one flow comparison.

I agree that after a proper test was done it could be diluted or dumbed down in its presentation but there will always be data to back up conclusions at least.

[jaydee]

Originally posted by gone_fishin
I did not express the masses part of my anal ravings very good. I was allluding to giving in to what the masses want as far as a test goes (they do not know what is required so why give in). As you well know, a blocks performance curve is not linear in respect to flow rate. Someone could easily skew a test to the dumb masses by running a really low flow for a block that is designed for a higher water presure. A set of flow rate points establishes a curve that one can see the direction performance is heading on either end. A really well block could be made to look like it is only slightly better than the pack with only one flow comparison.

I agree that after a proper test was done it could be diluted or dumbed down in its presentation but there will always be data to back up conclusions at least.

That's the answer I was looking for on the flow rate issue and agreed. Luckily it is one of the easier and cheaper measurments to get reasonable accurate. Now what about inlet and outlet temp? I find it would be pretty difficult to measure a .5C raise in temp with equipment even .25C inaccuracy curve. So why again is this measurement important and usefull and worth the money to fork out?

[gone_fishin]

Originally posted by jaydee116
That's the answer I was looking for on the flow rate issue and agreed. Luckily it is one of the easier and cheaper measurments to get reasonable accurate. Now what about inlet and outlet temp? I find it would be pretty difficult to measure a .5C raise in temp with equipment even .25C inaccuracy curve. So why again is this measurement important and usefull and worth the money to fork out?

Do you want a narrow line for a performance curve(relating to specific data points) or a highway (describing a vast swath of possibilities along the way)?

[bigben2k]

JD: I think you're getting closer...

If you test blocks a, b, c, d, and e, and you get say, 34, 35, 38, 40 and 44 deg C respectively, you'd tend to place them in that order, right?

As GF pointed out, you only measured it for one flow rate, and that's not fair, because one block could outperform another at another flow rate, where it didn't before. Even one or two years back, you'd get an occasional block whose curve would cross another block, but with today's variety of designs, it's more than just a fluke.

Back to the order...

If you use a thermocouple, and some meter that gives you +/- 1 deg C, which would be ok, then you can't really say that block b outperforms block a, because block B's temp could actually be 34, and block A's temp could actually be 35, which would actually reverse the order of those two.

[edit: rambling removed]

Now I don't know if you had all that figured out, but I thought I'd recap it, at least for everyone else's benefit. We have 630 views on this thread alone, as of now, so someone is watching!


[edit: rambling removed]

[jaydee]

Originally posted by gone_fishin
Do you want a narrow line for a performance curve(relating to specific data points) or a highway (describing a vast swath of possibilities along the way)?

I understand where your coming from but you nor Ben answered the question. I as with the majority of people are concerned with what temp the block keeps the die, not how much warmer the water is after it exits the block. So again why bother with the measurement when you have a die temp measurement? Is there some other use for it? Or is it taken to backup what your die temp is?

And also whats the point in taking the base temp of the block? I find this to be pretty impossible anyway...

[pHaestus]

I thought I explained earlier that I use these measurements to verify that my test setup is working properly. This is something I find useful (confidence in my results).

So to recap: what we have here is people with experience and/or expertise telling you something wont work or is really difficult. On the other hand we have those without experience full of enthusiasm and sure it's all straightforward.

[bigben2k]

[edit: rambling removed]

BTW, I take it back: that DP250 meter isn't going to cut it. With an accuracy of +/- 0.025 deg C, that means a differential of +/- 0.05, which is next to useless.

[edit: rambling removed]

[Blackeagle]

http://thermal-management-testing.com/Hdie1.htm

http://thermal-management-testing.com/Hdie2.htm

http://thermal-management-testing.com/die3.htm

[jaydee]

Originally posted by pHaestus
I thought I explained earlier that I use these measurements to verify that my test setup is working properly. This is something I find useful (confidence in my results).

Question still not answered though. How is either the inlet/outlet and/or base plate temp a verification? What makes those temps any better than the other? And how are you taking these temps for only a few hundred $'s accurately? Stuff isn't adding up in this thread. We have Ben saying it will take several 1,000 $'s to make a accurate measurement for this and we have you that says you got a couple hundred $'s and say you can take those measurements accurately enough to be useful.

So to recap: what we have here is people with experience and/or expertise telling you something wont work or is really difficult. On the other hand we have those without experience full of enthusiasm and sure it's all straightforward.

No, what we have here is some claiming to be experienced (some are some are not) and not sharing their claimed knowledge to inform the less knowledgeable. Instead we have "do it this way or don't do it at all" with no explanation why it needs to be done that way.

There is way to much conflicting input here to be useful IMO.

[jaydee]

Originally posted by Blackeagle
http://thermal-management-testing.com/Hdie1.htm

http://thermal-management-testing.com/Hdie2.htm

http://thermal-management-testing.com/die3.htm

Maybe better off in one of the other sections?

[pHaestus]

I have two YSI thermistors for my digitec 5810s that, when placed in a container of water, read the same temperature exactly (they are 0.01C res) over the 25-35C water temperature range. Since this is the case, I find the delta T across the waterblock to be useful to me when setting up the loop and playing around with my gear. I like to watch the change in delta T with flow rate; they are bright red LEDs and it's something to do for the testing period (which takes a long time). I don't buy my stuff retail because I don't have a closet full of money. I don't see why the private checks I do to get a feel for how the testing is going has become such a big deal.

The CPU die and the wb baseplate I both take with a small diameter type T thermistor. The difference between CPU die temp and the baseplate temp gives me an idea of the "goodness" of waterblock mounting. I don't see why measuring temperatures at both sides of all the junctions would be a bad thing? It isn't any extra work on my part and is sometimes useful.

[Blackeagle]

This being the temp. measurement topic area I thought they would be of help here.

I have not read all the differant topics however JayDee so if there is another topic you feel it would help in then please post it. I'll gladly post them there as well.

pH,

I like the way you have a redundant set of readings to cross check your results. Not only does it give you something to do, as you put it, it must also give you the oportunity to spot something going wrong more quickly.

[bigben2k]

Still Googling...

I found an article of interest, on the topic of "Data Acquisition". It's from the August issue of "Test & Measurement World" (another mag I read often), under the "Automotive & Aerospace section. Go down to the article entitled "Avoid data-acquisition mistakes". Here's the link:
http://www.reed-electronics.com/cont.../80103aatr.pdf
(PDF, 4.86 MB)

[pHaestus]

big file for small article.

Yes being digital literate but not analog literate is my problem. I have a nonworking Digitec with ADC and 3 working ones without. If I were clever I could build the ADC for all the working ones and then use a data logger to pull all of their data to a PC serial port. Alas I am not well versed in such.

[jaydee]

Originally posted by Blackeagle
This being the temp. measurement topic area I thought they would be of help here.

I have not read all the differant topics however JayDee so if there is another topic you feel it would help in then please post it. I'll gladly post them there as well.

http://forums.procooling.com/vbb/sho...&threadid=7808

[jaydee]

Originally posted by pHaestus
I have two YSI thermistors for my digitec 5810s that, when placed in a container of water, read the same temperature exactly (they are 0.01C res) over the 25-35C water temperature range. Since this is the case, I find the delta T across the waterblock to be useful to me when setting up the loop and playing around with my gear. I like to watch the change in delta T with flow rate; they are bright red LEDs and it's something to do for the testing period (which takes a long time). I don't buy my stuff retail because I don't have a closet full of money. I don't see why the private checks I do to get a feel for how the testing is going has become such a big deal.

The CPU die and the wb baseplate I both take with a small diameter type T thermistor. The difference between CPU die temp and the baseplate temp gives me an idea of the "goodness" of waterblock mounting. I don't see why measuring temperatures at both sides of all the junctions would be a bad thing? It isn't any extra work on my part and is sometimes useful.

I think there is a level of mis communication here. I am not questioning your capabilities or your testing methods. What I want to know is if this is all really needed for "other" testers just getting into it. Ben mentioned a minimum, well what is it?

What are the minimum measurements needed to make a decent review of a block?

Just trying to get something acomplished here. Once that question is answered we can move on to the equipment needed to do it. We spent two weeks so far and I see nothing in the form of progress here.....

[gone_fishin]

Jaydee, I will try to sum up my take on a hypothetical test regime, someone kick me if I'm wrong.

You asked, "What are the minimum measurements needed to make a decent review of a block?"


Mount - remount 10 times (more?)

(10) quantify mounting presure for each

describe tim application

(40) 4 flow rates each mount

(40) 1 water presure measurement per flow rate run

(10) voltage and current measurements to quantify applied heat (steady state)

(80) inlet temp, outlet temp to verify steady state water temp (use as mounting indicator also)

(40) die temp reading (.01C res, +-.05C accuracy)per mount per flowrate (that's 40 more temps if you're counting along)

(40) bp reading (see above)

--------
260 total readings per block



Take the results and present them the way you want. Block A vs B or get anal with presure vs flow rate charts, mounting variance charts and all that. Now you have reproducable data to back up your claims assuming you have the equiptment calibrated correctly.

The multiple mounting verifies the comparability of tim joint application (error bars) and allows the calculation of an average bp temp measurement of the ten mounts. This is also where cross test platform comparability would suck ass. YOU could reproduce the results (get the same average) but your technique in applying the tim and mount presure will never be the same as anyone elses no matter how many words you use to describe it.

[jaydee]

Thanks GF, anyone else have a different opinion?