note that the blower V, I readings have been truncated to two dp
Right. Now is there a current sense resistor for those values, or is that the blower only, or blower plus sense resistor? Was it just the output of a variable DC power supply, or a Wii power supply?
(I think that is the older fan style, which I have one of also.)
Check the heat balance when the blower starts up..
Voltage input to blower ~12.18
Current input to blower =~0.38 Power input =~4.62W
Some of the blower power will be lost as motor heat to the outside...~0. 15 W
Some will increase the mass kinetic energy(due to speed up of bulk air)~ 0.15W
But most will appear as sensible heat in the airstream..
Look for approximately 0.4C delta T before/after blower.
There is no mention of resistance in the 2017 paper
Display MoreCheck the heat balance when the blower starts up..
Voltage input to blower ~12.18
Current input to blower =~0.38 Power input =~4.62W
Some of the blower power will be lost as motor heat to the outside...~0. 15 W
Some will increase the mass kinetic energy(due to speed up of bulk air)~ 0.15W
But most will appear as sensible heat in the airstream..
Look for approximately 0.4C delta T before/after blower.
There is no mention of resistance in the 2017 paper
Funny you should mention the heat balance.
I can take rough estimates from the Albiston data plots, and closely determine the airflow rate by solving for velocity (which holds pretty constant over all of the plots). Mizuno’s data leads to wildly variable air flow rates, usually nothing like the reported air flow. Even considering the lossy calorimeter.
Mizuno’s data leads to wildly variable air flow rates
Show wildly calculations for 120W 2017 excess heat spreadsheet. which is what I base my calculations on.
How is the Mizuno vacuum replication going?
Mizuno’s data leads to wildly variable air flow rates, usually nothing like the reported air flow.
I do not know what you mean by this. His data leads to no such thing. He measured the air flow rate carefully and repeatedly with two anemometers, a hot wire type and a vane type, and he found significant variations. He did several traverse tests and found no significant differences across the orifice. Repeated calibrations at a given power level produce the same results. So there is no indication variable air flow rates, wild or tame.
I do not know what you mean by this. His data leads to no such thing. He measured the air flow rate carefully and repeatedly with two anemometers, a hot wire type and a vane type, and he found significant variations. He did several traverse tests and found no significant differences across the orifice. Repeated calibrations at a given power level produce the same results. So there is no indication variable air flow rates, wild or tame.
Have you tried to solve for velocity using the delta T and reported power?
Have you tried to solve for velocity using the delta T and reported power?
Show wildly calculations please..
Show me yours and I’ll show you mine. It’s a big ugly spreadsheet but can probably be distilled.
Have you tried to solve for velocity using the delta T and reported power?
That is not how calorimetry works. You are doing it backward. You know that the air velocity is stable, because multiple instruments confirm that, in multiple ways. You know the Delta T is changing because that is confirmed with multiple instruments. The reported power is computed from those variables. You can't do it the other way around. Reported power is derived; you can't change a measured value to conform to a derived value.
Your suggestion is like saying that if we measure bamboo shoots every day, and they seem to be getting longer, we should try to solve for that by assuming the ruler is getting shorter. We know that is not the case. Rulers do not shrink. We know that the velocity is not changing because it is measured with multiple anemometers. We know the Delta T is changing because it is measured with three thermocopules and several ordinary thermometers. They cannot all be wrong, all to exactly the same extent.
Well, how about 2.3 m/s to 3.75 m/s or instead variable 125% to 60% heat recovery to equalize air flow rates?
Divide input (or reported output) Watts by heat capacity of air * density of air * delta T to get the necessary air volume, divide volume by area of outlet to get velocity required to move that air. That is the minimum air velocity required to move the volume of air to required to arrive at the outlet - input delta T, not including heat losses that are not captured at the outlet. The heat losses can be factored in, if desired.
My spreadsheet spits out air masses in STP, NTP, and actual TP (all using sea level pressure) which then leads to three calculated velocities (about 10% maximum variation) based on those results (to check for mixed up measurement standard effects).
That is how math works. Ideally, with great measurement techniques, we should also be able to derive the correct air density or heat capacity by solving the same equation instead for those quantities.
Well, how about 2.3 m/s to 3.75 m/s or instead variable 125% to 60% heat recovery to equalize air flow rates?
When two separate instruments based on different physical principles (heated wire and vane) both show the flow rate is 2.3 m/s, they both agree, and they are both rated and certified to something like 5% accuracy, then the flow rate is 2.3 m/s. It is NOT 3.75 m/s. That is out of the question. Instruments do not work that way, or fail that way. Add to that the smoke test and stopwatch, which is visible proof of the flow rate, using human vision, not an instrument. It is crude, but it would show a 60% error. It is inconceivable that all of these methods are wrong by 60%. That notion flies in the face of common sense, and everything we know about instruments. If aneometers were that unreliable, the heating and cooling in a building would vary wildly, changing 5 or 10 deg C uncontrollably, like the temperature in an 18th century log cabin heated with a fireplace. Our industrial civilization would not function if industrial grade instruments were as unreliable as you imagine they might be. Every day refineries would explode, and airplanes would fall out of the sky. (Not just a few times a year.)
Also, don't bother claiming that the flow rate is uneven. That is ruled out. It as confirmed multiple times with traverse tests, and the vane anemometer and smoke test shows the same numbers as the hot wire instrument. The vanes cover a significant fraction of the orifice. It averages out the total airflow more than the hot wire does. It gets the same answer.
When two separate instruments based on different physical principles (heated wire and vane) both show the flow rate is 2.3 m/s, they both agree, and they are both rated and certified to something like 5% accuracy, then the flow rate is 2.3 m/s. It is NOT 3.75 m/s. That is out of the question. Instruments do not work that way, or fail that way. Add to that the smoke test and stopwatch, which is visible proof of the flow rate, using human vision, not an instrument. It is crude, but it would show a 60% error. It is inconceivable that all of these methods are wrong by 60%. That notion flies in the face of common sense, and everything we know about instruments. If aneometers were that unreliable, the heating and cooling in a building would vary wildly, changing 5 or 10 deg C uncontrollably, like the temperature in an 18th century log cabin heated with a fireplace. Airplanes would fall out of the sky. Our industrial civilization would not function if industrial grade instruments were as unreliable as you imagine they might be.
Also, don't bother claiming that the flow rate is uneven. That is ruled out. It as confirmed multiple times with traverse tests, and the vane anemometer and smoke test shows the same numbers as the hot wire instrument. The vanes cover a significant fraction of the orifice. It averages out the total airflow more than the hot wire does. It gets the same answer.
I don’t disagree. Which is why the reverse calculation results are so perplexing.
Perhaps the shortage of readily comparable data leaves poor examples to test with calculations at present.
My spreadsheet spits out air masses in STP, NTP, and actual TP (all using sea level pressure) which then leads to three calculated velocities (about 10% maximum variation) based on those results (to check for mixed up measurement standard effects).
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Paradigmnoia Member Likes Received3,594
Well, how about 2.3 m/s to 3.75 m/s or instead variable 125% to 60% heat recovery to equalize air flow rates?
1.03 m/s gives reasonable agreements for the blower power input sensible heat output for the spreadsheet 2017
2.35 -3.75 m/ m/s would give very high sensible heat outputs .. iistead of 4 and 5W
the graph would show 15W and 19W
you need to show and tell data ..
Display More"
Paradigmnoia Member Likes Received3,594
Well, how about 2.3 m/s to 3.75 m/s or instead variable 125% to 60% heat recovery to equalize air flow rates?
1.03 m/s gives reasonable agreements for the blower power input sensible heat output for the spreadsheet 2017
2.35 -3.75 m/ m/s would give very high sensible heat outputs .. iistead of 4 and 5W
the graph would show 15W and 19W
you need to show and tell data ..
Try the 50 W calibration vs 250 W output at 50 W in and see how that goes.
Then compare to the Albiston data results even just eyeballing the temperatures.
I don’t disagree. Which is why the reverse calculation results are so perplexing.
You cannot reverse calculations! You cannot go from a computed value to modifying the parameters used to compute it. Calorimeters measure heat. They do not measure changes in air flow or thermocouple malfunctions. We know they do not, because multiple methods and multiple checks are made to ensure the air flow rate has not changed, and the thermocouples are not malfunctioning.
(Of course anemometers and thermocouples they do sometimes malfunction, but you always know when this happens, because you always check. As I said, multiple thermometers confirm the three thermocouples.)
If you measure bamboo shoot growth, and you have some reason to suspect your ruler might be shrinking -- however improbable that might be -- you can easily confirm that is not happening by comparing your ruler to another ruler. Just as easily, you can see that Mizuno's inlet and outlet thermocouples are correct by comparing them to the thermometers placed right next to them. Right there, in front of you! They cannot all be wrong by 60%. By exactly the same 60%. That never happens. Instruments never do that, and will not do that in the life of the universe.
Try the 50 W calibration vs 250 W output at 50 W in and see how that goes.
I calculate off raw data.. 3.75 m/s is wildly off compared to 1 m/s
Got some data?
Btw the boiling point of LiOH /LiOD solution cannot be
computed by the simple boiling point colligative assumption
as you did awhile back..to get something like 170C
the reason is that the assumption does not work in concentrated solutions,,
You cannot reverse calculations! You cannot go from a computed value to modifying the parameters used to compute it. Calorimeters measure heat. They do not measure changes in air flow or thermocouple malfunctions. We know they do not, because multiple methods and multiple checks are made to ensure the air flow rate has not changed, and the thermocouples are not malfunctioning.
(Of course anemometers and thermocouples they do sometimes malfunction, but you always know when this happens, because you always check. As I said, multiple thermometers confirm the three thermocouples.)
If you measure bamboo shoot growth, and you have some reason to suspect your ruler might be shrinking -- however improbable that might be -- you can easily confirm that is not happening by comparing your ruler to another ruler. Just as easily, you can see that Mizuno's inlet and outlet thermocouples are correct by comparing them to the thermometers placed right next to them. Right there, in front of you! They cannot all be wrong by 60%. By exactly the same 60%. That never happens. Instruments never do that, and will not do that in the life of the universe.
I am not claiming that it is the air velocity that is screwy. That is just where the discrepancy in the total calculation shows up, when compared to other instances. Once could solve for another piece of the equations instead. Air velocity is convenient, however because is not super finicky, and we do know in some cases what it is expected to be. Then the other inputs to the equation can be massaged until the correct velocity pops out... perhaps indicating where something might be a little off.
If roughly the same air velocity came out almost every time, then that shows how solid the whole calculation is. But the variance could come from other measurements, or calculations along the way to calculated power results, for example.
The original idea was to see how much the air velocity would have to change, if that was the cause of apparent excess heat. (For 16.5 W about 0.5 m/s in one instance). A simple test to see if a velocity change was: possible, unlikely, impossible, obvious. Or does something else look more feasible or at least possible? (For 16.5 W about 1.0 C dT in the same instance). Or is extra heat the obvious cause because alternate explanations cannot mathematically work? (This would be ideal).
But is much messier than that, so far.
am not claiming that it is the air velocity that is screwy.
Thanks for that... the term wildly doesn't match with my calculations off raw data
If everything were super clean, it would be possible to determine if the heat capacity used in the calculations was for 0 C, 20 C, or 40 C and if the air was supposed to be dry or humid.
