Temperature measurement

[bigben2k]

Following discussions on the heat die here (http://forums.procooling.com/vbb/showthread.php?s=&threadid=7808), as well as other bench requirements, here is where we discuss temperature measurements.



A recent related question came up (here (http://forums.procooling.com/vbb/showthread.php?s=&threadid=6967)) about the type T versus type K (last page).

[bigben2k]

pHaestus: there's an outstanding question to you, about type T versus type K thermal probes. Do you want to answer it?

[pHaestus]

http://www.microlink.co.uk/microlink/tctable.html

I assume 0-200C is of relevance here. It's also easy to make type Ts with very thin wires if that's your thing (see JoeC). I like my dual linear thermistors more than thermocouples, but the Type Ts are handy for inserting into wb baseplates and die simulators.

[bigben2k]

[edit: rambling removed]


The temperature measurements is a really critical component of a test bench, so I'd like to tackle that question, and get to some kind of idea as to what level of accuracy we're all going to shoot for here. Everything else falls back on this.

[pHaestus]

Well the key thing is to have some way to periodically check your probes and calibrate them. This means that you need a single really accurate temperature monitoring device for cross calibration, a device specifically designed to standardize/recalibrate, or you need to budget for getting them professionally calibrated periodically. I honestly don't have a ton of experience with thermocouples but have been told before that linearity is a concern. It isn't like a thermistor where there's usually just an offset when they are calibrated, right? They work through Seeback effect and the equation is much more complicated.

On a budget, I suspect that something like a Fluke 2190 (get the multiplexer and you can have LOTS of probes) and type Ts is about as good as you can do.

For price/performance on temp monitoring, do not forget that being able to dump the readings to a PC is worth some money. I have analog temp readers now and it is a hassle.

[pHaestus]

Oh and as far as temperature measurement discussion goes:

You will need to measure (at a minimum):

water inlet
water outlet
waterblock baseplate
die

I also measure ambient air and radiator outlet temperature (just because I have the capacity to do so).

What accuracy is truly needed? I hear words like analytical vs comparative batted around in e-mail exchanges. Are you distinguishing the two based purely upon the accuracy of temperature measurement?

[Since87]

Originally posted by pHaestus
You will need to measure (at a minimum):

water inlet
water outlet
waterblock baseplate
die


Although I can see the desireability of knowing all these temperatures and more, I'm not sure I see the "need" to measure more than the die and the water inlet temperature.

Water outlet temperature can tell you the amount of heat the waterblock is dissipating, but assuming a 'perfect' die simulator, I'm not sure it is a necessity. (Obviously this test should be done to measure the quality of the die simulator.)

If it turns out that the die simulator 'leaks' too much heat, it may be desirable to make the delta T between inlet and outlet water the measure of heat transfer. This requires extremely good accuracy and resolution of the temp sensors though. (Not saying that extremely good accuracy is not needed anyway. Just that doing this would make the need greater.) It also requires extremely accurate flowrate measurement.

Alternatively, the water outlet temperature could be ignored (during actual waterblock testing) and 'leakage' of the die simulator characterized. This would require an ambient measurement though. (Since 'leakage' will vary with the deltaT between ambient and die temp.)

I don't see the value of, or a way to practically implement, measurement of the WB baseplate temperature. Few waterblocks of major interest these days are going to allow for placement of a temp sensor in a useful location.

[pHaestus]

Since87:

You are right; the baseplate and water outlet temps are mostly for the tester's internal checking and peace of mind and they aren't carried forward in any calculations. But here is how I am using them:

I find the baseplate temp useful as I compare to Bill's previous data (I am using a block that he also tested so the hole is in an identical spot). With my CPU I just don't know the power applied and so I am using the delta t die to water, delta t die to baseplate, and delta t water out to in all together to see if I can things to correlate. I guess this isn't explicitly needed when everyone is using die simulators, but then again if every unit is insulated differently...I also use the baseplate temp to track my reproducibility at waterblock mounting/paste application. YMMV I guess on the usefulness of it.

I look at the water inlet and outlet as important from a heat balance standpoint. If your die simulator is "leaking" then you can pick that up with these measurements pretty easily. If you don't do a check like that then you are going to have some pretty widely varying C/W values among different benches even with good thermal monitoring. This is probably why heatsink testing from commercial sources reports such widely varying C/W values.

[Since87]

Originally posted by pHaestus

I find the baseplate temp useful as I compare to Bill's previous data (I am using a block that he also tested so the hole is in an identical spot). With my CPU I just don't know the power applied and so I am using the delta t die to water, delta t die to baseplate, and delta t water out to in all together to see if I can things to correlate...

Yes, that makes sense. I think one thing many people who are thinking about testing water blocks don't consider, is that you need more than the equipment which composes the test bench. You also need additional equipment to verify the operation of the testbench.

[bigben2k]

Ok, to recap:

-Need to measure:
1-the heat die temp
2-the block water inlet temp

-need a highly accurate probe, for periodic calibration.

-Alternate temp measurements:
1-block outlet (highly accurate, to measure the heat flux)
2-ambient air
3-water block baseplate (where available)
4-radiator outlet (water)


[edit: rambling removed]

[jaydee]

Originally posted by bigben2k



Off to Google for Fluke 2190... Thanks for the tip!
Do they still make these? Anyway I was going to buy one of these http://www.tequipment.net/FlukeThermo54.html The 54-2 series with data logging and dual probes. but it is only dual probes and it costs $300.

If you look here at the price page: http://www.tequipment.net/FlukeThermo54MO.html
and scroll down you will notice the probes are not exactly cheap either.

Probably not the lest expensive place to get this stuff though.

[bigben2k]

I was just looking at the same one.

The 50 series can return a value within +/- 0.3 deg C, regardless of the thermocouple used. The T type probe though, would have an absolute error of +/- 0.5 deg C, where a type K would be +/- 1.5 deg C.

[edit: rambling removed]

The different models have various extra features, like logging, dual input (and differential output), etc...

[jaydee]

Originally posted by bigben2k
I was just looking at the same one.

The 50 series can return a value within +/- 0.3 deg C, regardless of the thermocouple used. The T type probe though, would have an absolute error of +/- 0.5 deg C, where a type K would be +/- 1.5 deg C.

Couldn't we just calibrate a type K? Could we make/use our own thermocouples?

The different models have various extra features, like logging, dual input (and differential output), etc...
Yeah, my second plan was to buy one of the cheaper ($150ish) Fluke 50-2 series and just use it to calibrate the sound card mod thing OR I was going to get one of those maxim kits pH is using.

My head is killing me today. Damn cold front and rain! Bah, back to work....

[Since87]

Originally posted by bigben2k
Also, I'm going to bring up the coolant testing temp again: you suggested 30 deg C, because you're having difficulty maintaining 25 deg C. My concern with that, is that a higher delta T (block to ambient) may increase those secondary losses. (am I off my rocker here?)

Ben, if you can't answer this question yourself, what hope is there, that you are going to be able to cover all the bases in setting up an accurate test bench?

Originally posted by bigben2k
If we're stuck with Type T probes, then what's our margin of error? +/- 0.5 deg C?

Which is of course, absolutely useless when trying to measure the heat dissipation of the block by measuring the delta T between inlet and outlet water temperature.

Originally posted by bigben2k
Since I'll be using a heat die, if I want to measure those secondary losses, then I am stuck with measuring a block's coolant inlet and outlet temps, with high accuracy.

And if you don't measure the die simulator's secondary losses, then all of your measurements will be suspect.

[Since87]

Temp measurement link. (http://cp.literature.agilent.com/litweb/pdf/5965-7822E.pdf)

[bigben2k]

[edit: rambling removed]

[pHaestus]

since87: GREAT link. Informative +1. The comments about sources of error are most useful for tc users who are buying parts off ebay.

[myv65]

Originally posted by bigben2k
Exactly.

I already have a rough # for that secondary loss: roughly 2%. It's clear to me that it's significant enough to warrant a measurement of it. My question was: to what extent is a higher delta T, block to ambient, is going to skew the results?

On the other hand, who cares, if we're going to measure that secondary loss.

But +/- 0.1 deg C on each probe, isn't going to pick up that difference.

Ben,

Slow down and think a little before you post. I realize that rambling is one way to work things through, but I generally keep it to myself rather than putting it to paper, so to speak.

To your original question, yes, increasing the ambient will increase the amount of heat leaving via a secondary pathway. That should be self-evident as the delta-T from the die to air drives secondary losses. Assuming the air remains constant and you raise your fluid ambient, more heat will transfer to air. Unfortunately, it is not so simple as assuming a constant convection coefficient to the ambient air as you are off in the realm of "natural" or "free" convection where a significant portion of the air velocity is a function of the density change as it warms. You can pot-shot it and take copious measurements to back up your guestimate.

A rather fundamental thing is that the repeatability of pretty much any online temperature sensor will be worse than the delta-T of fluid through the block. This has been said by several here, but it isn't apparent that the meaning has truly sunk in yet.

As for measuring secondary losses, one way is to install a well-insulated block with no flow. Then you modulate power to the die simulator and measure temperature of the die. You get a feel for how much power is dissipated vs die temperature when (almost no) power is going into the block. The obvious goal is to insulate the simulator such that you can scarcely turn the power down low enough to avoid a high die temperature.

[bigben2k]

[edit: rambling removed]

[RoboTech]

Hey Ben,

IMHO thermocouples (whatever type) are good for applications that don't require high accuracy. Even with a quality TC and calibrated instrument you won't be able to do much better than about +/-0.5 deg C. TCs big advantages are they are inexpensive and widely used throughout industry (available in all shapes and sizes). If you need better precision and accuracy then 4-wire platinum RTDs are the next step up. They are more expensive but in a best case situation can provide +/- 0.01 deg C accuracy.

So I recommend looking at RTDs for the die temp and water inlet. Don't even bother with TCs. Even with good RTDs installed on the inlet and outlet of the block, I doubt we will be able to measure the Delta T across the block accurately enough enough to define the actual heatflow. To define Q based on mass flow rate and Delta T would require even more accurate (0.001?) temp readings and very accurate (0.1?) flow rates.

In regards to calculating the thermal die secondary losses - my plan is to...

1) insulate the block quite well (thermal stand-offs, air gaps and ceramic insulation) to help minimize secondary losses as much as possible.

2) Measure the secondary losses by firing up the die and applying just enough power to bring it up to a typical steady-state operating temperature (i.e. 40 C) at a known and controlled amb air temp (with the die surface insulated). Once the die equillabrates at temp, virtually all of the power going in (E x I) is going out via secondary heat paths (since there is no WB sucking heat out the top). Since I'm not far enough along to have actually done this I don't know how well it will work.

Well, so much for lunch... :)

[bigben2k]

Going over RTDs now. That Omega site has some info.

I should also point out that Bill used an RTD in his original heat die.

[pHaestus]

You realize you are doing this in exactly the wrong manner, right? I would suggest:

1) Come up with goals for the testing
2) Run some numbers with different levels of accuracy in the temperature and flow rate and power measurement.
3) Price out gear that will get you where you want to be error-wise. This will let you meet your goals with the minimum outlay of cash.

I get the impression that your goal in #1 is "to get the exact correct answer", and that's going to result in a $ value for 3 that's near infinity.

I also get the impression that there is a bit of snake oil being sold in this whole WBTA thing. Quality testing just can't be done without a big investment in both time and money.

An allegory for the interested: I recently made some arsenic samples of known chemical composition in my lab. I started with a 1000mg/L standard that I diluted to 0.1 mg/L using an analytical balance accurate to 0.1mg and with density of water adjusted using room temp. I sent these to 4 professional laboratories in my region and asked for As analysis. The point? (1) none of the labs reported 0.1 mg/L (but one was "close enough" with 0.12ppm) (2)%RSDs were 1-2% max (3) there was a range from 0.02 to 0.4mg/l for the concentrations.

So what happened there? Each lab used probably a $100,000 instrument with a professionally trained technician. Each lab had good reproducibility of measurement, and none of the labs were correct.

Rather than spend thousands of posts on talking about the minor details, I would suggest starting with error and uncertainty and how to propagate error forward. That would be my first standard if I were a WBTA; all points must have error bars. Equipment needed would all follow naturally from that standard.

[bigben2k]

[edit: rambling removed]

[bigben2k]

[edit: rambling removed]

[jaydee]

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.....

[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! :D

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. :D

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)?:D

[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)?:D
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/contents/pdf/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/showthread.php?s=&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?

[pHaestus]

I don't think I meet the stated requirements of G_F: My 2190C setup is 0.01C res but no better than 0.3C absolute accuracy. That's what I read die temp and wb baseplate temp from btw.

I don't think the raw accuracy numbers are as important as moving your error along in your calcs and being careful to reproduce each test as close as possible. If I find a rare block that I can get a reproducible mount upon and the std deviation for the first 3 or 4 mounts is extremely small then I probably will stop there. If I have trouble getting a good mount I might do more. Be honest! I can't distinguish 0.1C differences in a block's performance. I can't control flowrate batter than 0.05 GPM. I am not confident that these sets of numbers are statistically different. It's ok! Everyone who has tried to run wb tests will understand :)

I have seen testing very carefully done by people with a minimum of expense (look at Hoot's stuff at overclockers and Cathar's block testing for examples. Probably wrong numbers in absolute terms but very useful and as controlled as they could make them with their stuff). There was a guy at a British website who did some nice testing on flowrate restriction using nothing more than a bucket and a stopwatch :) The key is to be honest about the confidence in the results and to repeat tests and become experienced. For all Ben's talk of analytical testing, it is extremely unlikely you'll all come up with a "true" number for a waterblock's performance even if everyone uses exactly the same testing gear. Practice is really the best teacher on this stuff.

[gone_fishin]

I've seen no absolute proof that Cathar ever quantified a difference in performance (other than a rough .5C, well within his margin of error) with his new block over his ww block. If there is a performance increase the source of the increase has not been pinpointed (witness Les's argument on bp flatness from machining differences recently). Cathar's two blocks are a perfect example of why resolution and accuracy are needed for any answers. I seriously doubt he could quantify a difference with his homestyle test equiptment. I believe that a difference has been noted through higher overclocks, but chips sometimes do overclock differently over time (not diffinitive). His block has so many variables to it that I do not see how he could have optimized them all together without SEEING a changed variables effect. That being said there is nothing wrong with applying ones theories through invention but even trial and error has its limits when you cannot identify an error.

[jaydee]

Originally posted by gone_fishin
I've seen no absolute proof that Cathar ever quantified a difference in performance (other than a rough .5C, well within his margin of error) with his new block over his ww block. If there is a performance increase the source of the increase has not been pinpointed (witness Les's argument on bp flatness from machining differences recently). Cathar's two blocks are a perfect example of why resolution and accuracy are needed for any answers. I seriously doubt he could quantify a difference with his homestyle test equiptment. I believe that a difference has been noted through higher overclocks, but chips sometimes do overclock differently over time (not diffinitive). His block has so many variables to it that I do not see how he could have optimized them all together without SEEING a changed variables effect. That being said there is nothing wrong with applying ones theories through invention but even trial and error has its limits when you cannot identify an error.
He said the Cascade is 2.5C better than the White Water last I heard.

So your basically saying give up on testing? As from everything I have read from you there is no right way to do things no matter what equipment is used....

[pHaestus]

I was referring to the original design process of the whitewater block. The absolute numbers were irrelevant but the changes that he made through that process were validated through testing and could be seen in the final product.

[gone_fishin]

Originally posted by jaydee116
He said the Cascade is 2.5C better than the White Water last I heard.

So your basically saying give up on testing? As from everything I have read from you there is no right way to do things no matter what equipment is used....

No, I'm saying doing testing right could give some answers that are helpful in designing a block. I stand corrected if it is 2.5C (is this verifiable?). Do it right not halfassed is all I was ever saying in these discussions.

[gone_fishin]

Originally posted by pHaestus
I was referring to the original design process of the whitewater block. The absolute numbers were irrelevant but the changes that he made through that process were validated through testing and could be seen in the final product.

I believe that his main decisions came through the use of a mathematical simulator that he put together. I was of the belief that this influenced his design decisions not the testing. His testing showed promise but true validation came when BillA slapped it on his test die.

[bigben2k]

[edit: rambling removed]

[jaydee]

Originally posted by gone_fishin
No, I'm saying doing testing right could give some answers that are helpful in designing a block. I stand corrected if it is 2.5C (is this verifiable?). Do it right not halfassed is all I was ever saying in these discussions.
But doing it right, by what you have stated to be right, is not going to be possible by anyone here, not even pH. So we should just all give up? or do our best to eliminate as many errors as possible and move forward?

Also I guess it was 2C, was sure I seen 2.5C somewhere but stand corrected:
originally posted by Cathar
Straight away on the first remount I'm seeing a full 2.0C clear lead over the best result I had previously gotten with the White Water over 12 mounts of that block. This is using a T'Bred B at 2400MHz/1.85v running BurnK7. This is significant because it was my design goal to gain a full 2C, and secondly, it's just the first time I've mounted the block. History tells me that I rarely get it right first time, so there may be a little bit more hiding there as I remount to test again.
http://forums.procooling.com/vbb/showthread.php?s=&threadid=6666&perpage=25&pagenumber=6

[Cathar]

I never state that my testing is accurate. It is true that until BillA tested the White Water, then my results weren't really validated.

My Cascade results ranged from 1.5-2.0C better than my reference White Water block here in my testing. That's of course with the disclaimer about the (gross) inaccuracies of my testbed.

The Cascade results have been partially independently validated by the German water-cooling site who tested the Cascade against the DTek White Water, and found the Cascade to be 1.5C in front. The aluinium topped DTek White Water is an exact copy of the original White Water for the cooling specific bits (middle and base plates).

The German site used an Eheim 1046 with a large number of added restrictions, so admittedly this was an extremely low flow test. In my testing the Cascade does pick up a bit of performance separation over the White Water as the pumping pressure is increased.

Now what that all tells me is that despite the inaccuracies of my testbed, I can still get a somewhat decent indication of what's going on. It's not accurate in any way, but it's at least good enough for me to develop the block designs and pick a difference and really that's all that I was after.

True validation comes from independent testing, because let's face it, it is perhaps never wise to take a block maker's word on how their product performs?

[pHaestus]

I wasn't trying to put you on the spot Cathar or hold your testing methods up as the ideal. I merely meant that it was a good example of you you can get good results from "typical" equipment with being careful and with a bit of thought. You can throw thousands of dollars at the problem as well, but without attention to detail and careful experiment design it still wont be reliable. That was my point.

[jaydee]

God damn, where is that banging head off wall smilie?

We got GF saying "do it right or don't do it at all" with his strict list of minimum required testing which will take very expensive equipment.

And we got pH who says it can be done with hardly any money in the equipment as long as the method it good..... i.e. Cathars and his own testing methods.

We got Ben.....well.....we got Ben.....

Cathars way doesn't require base plate or inlet/outlet temps yet he is still able to come up with fairly accurate "relative" numbers and has built 2 of the best blocks on the market using those methods.

So what is "good enough". :shrug:

Bah....

[Cathar]

It's okay Ph, you didn't put me "on the spot", well maybe a little, but I did understand where you were coming from.

I was just wanting to highlight my personal views on the matter as really being somewhere in-between the sides being taken in this thread.

Call me a fence-sitter if you will. I perfectly understand the respective needs for both approaches.

[gone_fishin]

Using a test method such as Cathar has done to help give indications in his developmental process is far different then stating block A is x amount better than block B and publishing it for public consumption (doing so will effect the going rate in the free market and open yourself up to lawsuit so you better be able to back up that data). Different horses for different courses.

What are the goals of this discussion, gettin kinda hazy in here.

[pHaestus]

Depends on what you are doing JayDee. I assume what you care about are (a) bitching :D and (b) improving the blocks you make yourself (in no particular order).

For me, I care about building a testbed where I can get the same results for a block on day one as on day 500 with good enough accuracy to write reviews for this site. I haven't exactly spent "hardly any money" on my own testing setup (I think it is still measured in hundreds of dollars spent rather than the thousands thrown around in this thread though). Can I get that last bit of accuracy needed to separate every single good waterblock from one another? Probably not. I can certainly give some good evaluation and buying advice though. If a $100 block and a $30 block are too close together for my testbed to separate then I'd go with the $30 one, for example.

I also care about temperature measurement and monitoring in my own personal PCs that I run daily. That's where all my messing with Maxim ICs and CF633s and gameport thermistors comes in. If you calibrate those types of setups and use a bit of thought in where you place sensors then you can really enhance your ability to troubleshoot your cooling and your system. Would I trust those kinds of methods enough to do a Procooling waterblock roundup with them? Nope. But I trust them with my $1000 PC (go figure).

As for Ben he cares about googling and blue sky and his post per day count. I wouldn't make big purchases based upon that.

I guess what I was trying to say (and missed the mark) with the earlier examples of good work done by testers using cheap equipment is that a testbed is an evolving thing. I started off with an interest and a minimum of equipment. I assumed it would be easy; I am a bright fellow after all. As I ran tests I realized there were some flaws with how I was doing things. I'd correct the human errors as well as I could, and then when I was still bumping up against problems I would upgrade a part here and there. Add the ability to measure water temps to 0.01C res with decent reproducibility. Add a bigger pump to offset that. Fiddle with how to control water temps. Add a die simulator and related hardware. Etc etc.

To me it is irresponsible to start some "Alliance" and make these recommendations that tons of money must be invested to get some "magical" accuracy. The errors in mounting coming from a tester who has never installed a socketA waterblock before and never worked in a lab are going to dwarf the accuracy of the equipment for months. Give things a try and see if you enjoy it. See if you can spare the time. If so, and if it's important to you, eventually a testbed will emerge. Do the best with what you have/can afford, be honest about your testbed's limitations, and upgrade as needed/as available. "I'm waiting to find that used with traceable certs" is a valid excuse for not going platinum RTD in my mind.

[jaydee]

GF I think your thinking in the lines of a manufacturers point of view when testing. I gave that up long ago. I have no desire to sell blocks and rapidly loosing desire to keep designing them for my own use.

I am more interested in things from a reviewers point of view at this point. I pretty much ruled out myself doing this over the last year though.

pH you hit it in your first sentance on your last post. I am more tired of people claiming ambient CPU temps with 500mhz OC at 1.95Vcore on AIR and would like a well layed out article (or even a website) devoted to measuring temps in computers that we can point these people to and tell them not to say another word about their temps untill they do the things in the article/site. I like your current articles but they fall short of the reasoning for doing what your doing.

I have been thinking about putting up a website devoted to just this subject. Problem is I need some more experienced people to assist in the information put on it. Something I am considering as opposed to this WBTA deal. I like procoling and all but the subject matter is just to broad to really cover temp monitoring well IMO. I would like the site to just be about temp monitoring computers and maybe even other things.....

[bigben2k]

Originally posted by pHaestus
...

As for Ben he cares about googling and blue sky and his post per day count. I wouldn't make big purchases based upon that.

...

Add the ability to measure water temps to 0.01C res with decent reproducibility. Add a bigger pump to offset that. Fiddle with how to control water temps. Add a die simulator and related hardware. Etc etc.

...

To me it is irresponsible to start some "Alliance" and make these recommendations that tons of money must be invested to get some "magical" accuracy.

...

Do the best with what you have/can afford, be honest about your testbed's limitations, and upgrade as needed/as available. "I'm waiting to find that used with traceable certs" is a valid excuse for not going platinum RTD in my mind.
I couldn't care less about my post count, actually. :p

[edit: rambling removed]

I'm sorry for my ramblings about that ultra high accuracy bit. I was just trying to figure out a (relatively) cheap way of measuring that secondary loss. Obviously, as Bill himself pointed out, it's beyond our capabilities/means. I certainly didn't mean to imply that we would need to spend huge amounts of money (used or new).


Going over some theoretical figures, I'm trying to figure out how each individual error applies to the result: the C/W. One thing that's stomping me right now (a brain fart), is, if I have a temp differential (die to water) error of say, +/- 0.2 deg C, given say, a 70 Watt source (measured at +/- 2%), then what's my C/W's error margin?

[pHaestus]

http://www.rit.edu/~vwlsps/uncertainties/Uncertainties.html
http://www.rit.edu/~vwlsps/uncertainties/Uncertaintiespart1.html
http://www.rit.edu/~vwlsps/uncertainties/Uncertaintiespart2.html

Fairly general overview. I have a set of old handwritten analytical chemistry lecture notes I actually refer to though for most basic stats.

One thing that's stomping me right now (a brain fart), is, if I have a temp differential (die to water) error of say, +/- 0.2 deg C, given say, a 70 Watt source (measured at +/- 2%), then what's my C/W's error margin?

Think about it logically. The upper limit on the calculated C/W will be when you overestimate the temperature differential by the largest amount and underestimate the wattage my the maximum amount. The lower limit would be the smallest temp differential divided by the largest wattage. So let's say you have a real 0.2C/W; that's a 14C delta T. The range of C/W you can get from your error is 13.8/71.4 =0.19 to 14.2/68.6 = 0.21 or your C/W value is +/- 0.01. That's actually pretty good; you'll see bigger differences than that from wb mount to wb mount.

Digitec and my YSI probes are guaranteed to 0.3C accuracy out of box. My Fluke is probably a little worse. This number is a worst case scenario statement from mfgr that the temperature will be within this range of the true temp; it is not a measure of how tightly the instrument responds to a change in temperature. I would expect the digitec to be offset by as much as 0.3C, but when using it to monitor changes in temperature the error in the delta T is much less. Meaning the linearity in response is quite good. I can't necessarily say the same about my TCs and so I don't care for them as much.

Um what I am saying I guess is I have bigger error bars if I want to compare my numbers with your numbers than I do if I want to compare a block I test on today with a block I test next month on the same setup.

[jaydee]

Originally posted by bigben2k
I couldn't care less about my post count, actually. :p


Seems as if post count has been visually turned of anyway?

[gone_fishin]

On the topic of temperature measurement, this PDF should be interesting. If nothing else it gives a good description of resolution, precision, accuracy, calibration, sensitivity, stability(system drift).

http://www.luxtron.com/product/product-pdfs/700seriescatalog.pdf

[Blackeagle]

Originally posted by gone_fishin
Using a test method such as Cathar has done to help give indications in his developmental process is far different then stating block A is x amount better than block B and publishing it for public consumption (doing so will effect the going rate in the free market and open yourself up to lawsuit so you better be able to back up that data).

It would seem that there are massive numbers of reviewing sites that are not to worried about law suits. Hell some have 15 block "shootouts" or "roundups", yet claim to be able to tell which is best.

I'm not sure who here posted it but, ".........the hardest part of a roundup, as they are usually done, is rounding up all the blocks."

Just pointing out that if legal issues were a restraint, we wouldn't see all those off the wall articles being posted.:shrug:

[Joe]

Originally posted by jaydee116
Seems as if post count has been visually turned of anyway?

Yep I removed it, I didnt want that to be a factor in discussions anymore. Would rather people gain credibility based off what they say not how many times they say it.

[gone_fishin]

Originally posted by Blackeagle
It would seem that there are massive numbers of reviewing sites that are not to worried about law suits. Hell some have 15 block "shootouts" or "roundups", yet claim to be able to tell which is best.

I'm not sure who here posted it but, ".........the hardest part of a roundup, as they are usually done, is rounding up all the blocks."

Just pointing out that if legal issues were a restraint, we wouldn't see all those off the wall articles being posted.:shrug:

That is true and evident by non action in the past. If watercooling were to get bigger and more big money was involved, you can bet there will be lawyers along for the ride. I agree not much of an issue now but something to keep in the dark recesses of the mind.

[jaydee]

Originally posted by gone_fishin
That is true and evident by non action in the past. If watercooling were to get bigger and more big money was involved, you can bet there will be lawyers along for the ride. I agree not much of an issue now but something to keep in the dark recesses of the mind.
This is an interesting point. I don't see how it can really be inforced though. Then again if the manufacturer had their own evidence of how well their blocks worked then we wouldn't need reviews in the first place. I think you could only get in trouble if the manufacturer had it's own results which are severly different than yours and yours were negative to theirs. Then they might be able to put some sort of image damaging law suit together. This might be a larger issue in the future.

[bigben2k]

Was Googling around this aft, and came across this little gem:
http://www.itl.nist.gov/div898/handbook/index.htm

Enjoy: I will! ;)

[bigben2k]

Time to stir things up a bit!

I'm looking into a mercury thermometer from Cole Parmer.

The purpose is to calibrate my temp probes, but firstly the temp readings on my chiller. I want to get as close to 25 deg C as possible, as the coolant test temp.

Link to thermometer:
http://www.coleparmer.com/catalog/product_view.asp?pfx=A&sku=0800130&cat=1&sel=0800130

That thermometer has a range of 19 deg C to 27 deg C, and is accurate to +/- 0.1 deg C. (ASTM# 17C)

The thing is, I don't know if the "ASTM method" is relevant: in this case, it's "Saybolt viscosity". Does anyone know?


The other problem I have is that this thermometer appears to be meant to be used "fully submerged". Although Cole Parmer provides a tutorial on how to compensate (calculated) for that, as far as I can tell, if I used it only partly submerged, I would be throwing off the accuracy of a reading by a maximum of 0.002 deg C. Is this of importance?


My third question would be: do I really need to get the NIST certificate (yearly?), and why?


Lastly, could I actually use this thermometer to measure a temp, while the pump is running, or would it be preferable to briefly stop the pump for a reading?

[bigben2k]

Bump!

Since that last post, I picked up the Cole Parmer thermometer. I'm preparing to run a series of test on the chiller, to measure the performance.

Thanks to Capt Foo Foo, I now have the software that goes with the chiller. It has full logging capability.

Now to figure out the validity of the chiller's temp readings... then a mod for more flow!

For now, since money is tight, I'm concentrating on picking up a multimeter and an oscilloscope. Both of those will also allow me to complete the redundant power array, another project that's been sleeping...

[BillA]

did you read the specs on that thing ?
"Immersion depth - Total", and its 275mm long
wheeee

[bigben2k]

Yep, sure did. I even have a compensation formulae, from Cole-Parmer, for partial immerson. Surprisingly irrelevant (but will still be applied).

[BillA]

sounds good Ben
your eyes are doubtless better than mine, but you will find the constant reading of that thing a pain
perhaps you could set an optical sensor to 'read' the reflective bead . . . . .
(thinking GPIB here 'cause you don't need the bandwidth)

[bigben2k]

Why don't I just remove my reticular implant, and hook it up to my pc, and log the data? ;)

I see your point. I'll try it out and see how it responds. Either way, I need to do something, anything... if I have to re-run the whole test series once i have my temp probes hooked up to my PC (the ones that will be used for the testbench), then I'll do that.

Either way, I have to get some decent results, so that when I swap the pump, I can measure the difference in performance of this chiller. No decent results -=> the pump swap is on hold until I can get some serious data.

[bigben2k]

In the mean time...


Here's a link to a table generator (for temp probes) I thought might come in handy:
http://listserve.minco.com/sensorcalc/