IMPROVED measurement of RADIATOR PERFORMANCE

[BoggledBeagle]

I already established the method in this thread:

Simple measurement of RADIATOR PERFORMANCE | TechPowerUp Forums

And arrived to some general conclusions which the improved measurement in my opinion will not change much:

Simple measurement of RADIATOR PERFORMANCE

I had two more rads on the bench... I mean washing machine! Those two rads working together were kicking out so much heat, that I cannot presume constant ambient temperature and I had to adjust my calculation. More details to follow. I would need to cut off bits of the case to fit the...

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However, I made some improvements to the method which will allow much more precise measurements, I also intend to test at different fan speeds. These improvements are IMO so big that my old results may not be directly comparable to the new results.

A datalogging thermometer will allow me to collect exact temperature at the correct time, and also will allow me to measure input air temperature exactly. 4 inputs will allow me to measure the temperature of both inlet and outlet water.

Insulated and covered water container has so low heat losses, that I may even ingore these losses in the calculation, but I decided to characterise the heat impact of the measurement system anyway.

A baffle around the air input will decrease the air back-flow in the rad, and serve as thermocouple holder for air temp measurement.

I also revised the calculation sheets.

Here are the pictures from the measurement of the system heat characteristics and the first measurement being prepared:





Here are the results of the test system without radiator:



After 7 hours, the temperature in the tank dropped by just 7,5°C, and that is with the water agitated in the tank and flowing through the tubes.

You can see, that the cooling power of the system itself now is most of the time in single digit of watts (and due to the pump power draw even changes in the heating power at the low temperature over ambient).

 

[BoggledBeagle]

I tested the cooling performance calculation from the flow rate and in and out water temperatures and I found out, that the bucket cooldown method gives me up to 15% higher results than the flow method. These resultsof the two methods are thus pretty close to each other. I think that the bucket cooldown method has a fundamental problem in the fact that from measured temperature in one spot I presumed that the whole large body of water had the same temperature. I think that the temperature of the water flowing in and out of the rad will be closer to reality.

I started exploring the flow method with great results, it will allow me to test different fan speeds easily.

Testing rad at 20% fan speed:



I already tested two rads at all combinations of push, pull, push-pull configuration and 20, 40, 60, 80 and 100% fan speeds. I will not be testing pull anymore. I always thought it works better due to pulling air through the whole unobstructed radiator core, but it works worse that push.

Testing EK X420M rad:



This a first proof of the concept results graph from the flow measurement, was very happy to see this:



Switching between 20, 40, 60, 80, 100, 70, 20, and 70% fan speeds.

Here is a mistake: I came to change fan speed from 20 to 40% to find out, that I by mistake dialed in 23%, I had to lower it to 20.

3% fan speed difference and 30W cooling power difference, surprising, right? Such a small change and it is so much apparent in the power results graph, it seems that changes of 1% of the fan speed would be distinguishable in the graph.



The results so far from the flow method:



I will remove the pull columns the next time.

Comparison between the two rads:



I think I am ready for radiator reviews...

I spent the whole Saturday doing this, frankly I had enough for the weekend.

 

[Arctucas]

You will be reviewing radiators?

Looking forward to that.

 

[InVasMani]

I tested the cooling performance calculation from the flow rate and in and out water temperatures and I found out, that the bucket cooldown method gives me up to 15% higher results than the flow method. These resultsof the two methods are thus pretty close to each other. I think that the bucket cooldown method has a fundamental problem in the fact that from measured temperature in one spot I presumed that the whole large body of water had the same temperature. I think that the temperature of the water flowing in and out of the rad will be closer to reality.

I started exploring the flow method with great results, it will allow me to test different fan speeds easily.

Testing rad at 20% fan speed:

View attachment 353368

I already tested two rads at all combinations of push, pull, push-pull configuration and 20, 40, 60, 80 and 100% fan speeds. I will not be testing pull anymore. I always thought it works better due to pulling air through the whole unobstructed radiator core, but it works worse that push.

Testing EK X420M rad:

View attachment 353371

This a first proof of the concept results graph from the flow measurement, was very happy to see this:

View attachment 353379

Switching between 20, 40, 60, 80, 100, 70, 20, and 70% fan speeds.

Here is a mistake: I came to change 20 to 40% fan speed to find out, that I by mistake dialed in 23%, I had to lower it to 20. 3% fan speed difference and 30W cooling power difference, surprising, right?

View attachment 353381

The results so far from the flow method:

View attachment 353382

I will remove the pull columns the next time.

Comparison between the two rads:

View attachment 353383

I think I am ready for radiator reviews...

I spent the whole Saturday doing this, frankly I had enough for the weekend.

Try moving the middle fan to the back edge of that shroud and/or the rear of the radiator in the middle and compare. I think at the edge of that shroud in the middle could potentially help similar to how fire fighters open a window and then take a fan set back a few feet from a door way to clear smoke quickly. It's basically that scenario in reverse.

It might help expel all the stuff push thru by the other two fans especially if placed at the rear lip of that shroud you made. Basically it would be pulling that heat output from a bit of distance behind the radiator and might work similarly. I don't know if the end results of that offset just push the air thru in the middle of the radiator or not.

Seeing how it compares would be interesting though. Especially just comparing a fan on the rear of radiator versus one set back a few inches from it since it might work a bit better for actually pulling. I think it depends in part how important removing the surrounding heat pushed-thru impacts things.

 

[BoggledBeagle]

You will be reviewing radiators?

Looking forward to that.

I do not know about that. This site has a rad reviewer already, but the reviews do not provide some objective rad performance results, just indirect information about CPU temperature and pressure drop. Radiators are cooling water, speaking about component temperatures has little sense because these are affected by a lot of other factors.

Now I have two different methods giving me similar results (15% difference at worst) and now I can quite quicky characterise performance of a radiator at different fan speeds and fan configurations. I think this information might be interesting to some people.

I spent quite a long time developing these methods and the datalogging thermometer was not exactly cheap either... I would like to get some money for the past and possible future efforts.

Try moving the middle fan to the back edge of that shroud and/or the rear of the radiator in the middle and compare. I think at the edge of that shroud in the middle could potentially help similar to how fire fighters open a window and then take a fan set back a few feet from a door way to clear smoke quickly. It's basically that scenario in reverse.

It might help expel all the stuff push thru by the other two fans especially if placed at the rear lip of that shroud you made. Basically it would be pulling that heat output from a bit of distance behind the radiator and might work similarly. I don't know if the end results of that offset just push the air thru in the middle of the radiator or not.

Seeing how it compares would be interesting though. Especially just comparing a fan on the rear of radiator versus one set back a few inches from it since it might work a bit better for actually pulling. I think it depends in part how important removing the surrounding heat pushed-thru impacts things.

I am not exactly sure what you mean, but my previous measurements had a problem that there was short and unobstructed path for the warm air expelled from the rad to go to the front of the rad and be sucked back in it.

Now the paper tunnel created at least 23 cm long path and the warm air with the lift force acting on it will prevent it to get back in the rad. I do not think this tunnel has any significant impact on the amount of air being sucked in the rad.

 

[InVasMani]

I meant moving the middle fan to more like where it says climate neutral on the shroud you made might work better or worse also just flipping that single fan to pull, but keeping the other two as push might alter things bit as well. I would think moving the middle fan that edge of the shroud would possibly help the most though. It's really depends if circulating out the expelled heat more rapidly is of more benefit than pushing more of it thru more surface area on the radiator though.

 

[ShrimpBrime]

Fun experiment for lots of different fans.

If you can find AFB1212SHE (Delta) it's an impressive rad fan. Loud as all bloody Hell. But if you want to really move air through a radiator, these will do the trick. You won't need push pull configuration, the results are minimal.