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Dienstag, 16. Januar 2024, 07:57
I am by no means an expert on this, but I typed this formula into ChatGPT and got back the following.Q=mcDT
The rate at which heat is transferred is directly related to the mass flow rate, by increasing flow you increase heat transfer. Flow rate is directly related to the total amount of heat transfer occurring. Its non proportional, as Delta T is decreasing, doubling flow isn't gonna double Q.
It does not say anything about “mass flow rate”,
Sorry that was my error in typing.It’s been a while since I took a physics or chemistry class lol, It’s the formula for cooling capacity.What you need is the Formular for the "heat flow" = "Power".
This Formular is similar to Q=mcDT but with a dot above the "Q" and the "m" to indicate this is per "time" - e.g. per second (1J/s = 1W)
Interesting, I myself have used chat GPT to try to understand flow/pressure/volume and their relationships in coolant pathwaysI am by no means an expert on this, but I typed this formula into ChatGPT and got back the following.
Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »DeathToTheWind« (19. Januar 2024, 16:08)
only the D5 is watercooled and still, it dumps such minute amounts of heat in the water that you can basically disregard it.
The temperature sensors are so imprecise anyway you'll probably have bigger measurement errors than pump heat "offsets".
If you use DDC pumps for space savings, they are air cooled so it won't trouble the measures during your tests.
What ChatGPT told you about flow rates influencing heat transfer is correct but in our case with computer watercooling, the energies involved are so low it makes virtually no difference as you saw.
Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »DeathToTheWind« (19. Januar 2024, 16:35)
The problem is those 8 are probably not in the same places in the loop, so you never know which ones read correct :pI also use 4 temp sensors and will be upping that to 8. I'm less worried about reporting inaccuracies with that many.
I also found that the Koolance ones seem to be the most accurate as all of their probes, including the inline ones, have temp probes protruding into the coolant path, as opposed to just buried in the wall.
Thank you for clarifying this.What you need is the Formula for the "heat flow" = "Power".
This Formula is similar to Q=mcDT but with a dot above the "Q" and the "m" to indicate this is per "time" - e.g. per second (1J/s = 1W)
Thanks for posting this link. I have encountered several Playground flows that calculate the amount of power in watts that a rad is dissipating but this was the cleanest one. Some of the others included smoothing filters.[/size]W=(lph) x (4.18KJ/Kg K@35C) x (DT) I use an aquasuite sensor that someone else created to calculate my cooling capacity with a virtual sensor.https://www.reddit.com/r/watercooling/s/Cp1UYwU24D
I am not sure this is a valid assumption. I built a test loop on a table that initially consisted of a D5 Next, Ultitube D150, a spinner flow indicator, a High Flow Next, and a ball valve. Coolant volume was ~500ml of distilled water. No CPU or GPU block, and no radiator. With an ambient temp of ~25°C and the pump running at 50%, I was surprised to see the water temp rise to over 40°C after running for ~30 min. The only source of heat in this test loop was the D5 Next and possibly to a lesser degree, the High Flow Next. I suppose that once large heat sources are added to the loop (CPU and GPU blocks), the pump waste heat may be relatively insignificant, but I was surprised that just the pump waste heat could increase the temp of 500ml of distilled water by 15°C that quickly with no rad to dissipate the heat.only the D5 is watercooled and still, it dumps such minute amounts of heat in the water that you can basically disregard it.
Interesting. I looked on Koolance’s website. Some of their temp sensor are thermocouples. The inline or butt-plug thermistor models are:I also found that the Koolance ones seem to be the most accurate as all of their probes, including the inline ones, have temp probes protruding into the coolant path, as opposed to just buried in the wall.
Agree. The accuracy of 10K thermistors is not high enough to use them for data calculations that involve temperature differences of 2 or 3°C. You can calibrate them at 0°C by immersing them in a glass of ice water but that does not guarantee that they will report the same values at higher temps. Even if you calibrated them in 5°C increments across the range encountered in a computer cooling loop, Aquasuite does not support offsets at different temps. Even with the limitations of the temp sensors and Aquasuite, I think it is possible to get rreasonably accurate values.NTC thermistors are notoriously inacurrate, so you'll have to cheat a bit with offsets in Aquasuite, and even then, the response will not always match between sensors. for a same temperature change, some will be reading higher, some will be lower.
My water temperature under load is ~2.5 °C above room temperature.
The only significant changes I see with this type of load are when the room temperature changes. Then the water temperature fluctuates.
However, when I increase the 3 fans of the upper 420 radiator from 490 to 740 RPM, the CPU temperature drops from 37.75 °C to 37.38 °C.
The problem is those 8 are probably not in the same places in the loop, so you never know which ones read correct :p
NTC thermistors are notoriously inacurrate, so you'll have to cheat a bit with offsets in Aquasuite, and even then, the response will not always match between sensors. for a same temperature change, some will be reading higher, some will be lower.
Are these the models you are referring to? Koolance does have spec sheets for these thermistors that list max temp but they do not accuracy. The thermocouple specs list a temp range and an accuracy of +/-1.5°C which is not that great.
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