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. I started exploring this 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 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?



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.