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We welcome all new members and hope to see you around a lot!
TOPIC: trying to understand the basic energy balance
#424
11 years 9 months ago
trying to understand the basic energy balance
If I understand the Celani apparatus it must be operating at steady state for the simple thermal balance equations to be valid. In other words you have a closed box immersed in a large energy sink. Electrical power goes in. Heat goes out. In the absense of an internal heat source the two fluxes must balance. eg.
power in + internal heat generated = heat leaving
If heat flux leaving is more than electrical power going in, and you are at true steady state, there must be heat being created inside the box. At steady state this energy balance is valid and independent of the heat transfer processes internal to the box.
To facilitate the measurement of heat flux out of the box, you force all heat to leave as conduction through the cylinder walls. If you achieve these conditions, you can calibrate for heat conduction which should only depend on the boundary wall temperatures assuming that the wall material properties (thermal conductivity) are constant over the temperature ranges encountered.
Ingenious.
If my simple understanding above is correct then one could improve the accuracy of this "instrument" by:
a) eliminating any heat transfer to the sink by IR radiation (eg. by coating interior of cylinder with IR reflective coating, or in a pinch wrapping exterior in tin foil)
b) enlarging the thermal inertia of the sink (eg. immersing whole apparatus in temp controlled water bath)
c) lowering the thermal conductivity of the cylinder walls to give larger temperature spread for a given heat flux
Some thoughts.
bob
PS.
If I'm not wrong, this simple energy balance equation loses its independence on internal workings of the box (wire properties, gas convection etc.) when the system deviates from this steady state. Transient analysis is possible but the equations are much more complex. Cause gets separated from effect in time. Internal thermal inertias come into play etc.
PS2.
Regardless of the end result, I must commend you guys on your open source approach to this problem of LENR validations.
power in + internal heat generated = heat leaving
If heat flux leaving is more than electrical power going in, and you are at true steady state, there must be heat being created inside the box. At steady state this energy balance is valid and independent of the heat transfer processes internal to the box.
To facilitate the measurement of heat flux out of the box, you force all heat to leave as conduction through the cylinder walls. If you achieve these conditions, you can calibrate for heat conduction which should only depend on the boundary wall temperatures assuming that the wall material properties (thermal conductivity) are constant over the temperature ranges encountered.
Ingenious.
If my simple understanding above is correct then one could improve the accuracy of this "instrument" by:
a) eliminating any heat transfer to the sink by IR radiation (eg. by coating interior of cylinder with IR reflective coating, or in a pinch wrapping exterior in tin foil)
b) enlarging the thermal inertia of the sink (eg. immersing whole apparatus in temp controlled water bath)
c) lowering the thermal conductivity of the cylinder walls to give larger temperature spread for a given heat flux
Some thoughts.
bob
PS.
If I'm not wrong, this simple energy balance equation loses its independence on internal workings of the box (wire properties, gas convection etc.) when the system deviates from this steady state. Transient analysis is possible but the equations are much more complex. Cause gets separated from effect in time. Internal thermal inertias come into play etc.
PS2.
Regardless of the end result, I must commend you guys on your open source approach to this problem of LENR validations.
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#426
11 years 9 months ago
trying to understand the basic energy balance
Thanks for you attention.
You make some valid points, we are aware of these issues and have in our schedule a number of up and coming experiments that will address or make irrelevant many of the discussion points you raise.
The next few months is going to be really exciting.
B
You make some valid points, we are aware of these issues and have in our schedule a number of up and coming experiments that will address or make irrelevant many of the discussion points you raise.
The next few months is going to be really exciting.
B
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#432
11 years 9 months ago
trying to understand the basic energy balance
Just tried to post this to the Feb 5 blog comments section, but didn't appear to work. Apologies if this is a repeat. That blog was discussing a new refined apparatus and protocol. Here is the comment:
"Just curious. If the inside of the quartz tube is under vacuum, isn't that forcing the primary heat transfer from wire to outside (calorimeter) to be via IR? ie. vacuum is a very effective insulator. If so isn't that going to mess up the interpretation of the temperature readings on the surfaces of the quartz tube? ie. thermocouples can read IR directly. To me it makes more sense to leave gas in the tube to promote convective/conductive heat transfer away from the wire and then calibrate the conductive transfer across the glass surface. At steady state conditions the interior heat transfer processes fall out of the energy balance equations and don't matter. electiral in + LENR heat = heat flux across wall of quartz tube. Am I missing something critical here?"
Thanks.
bob
"Just curious. If the inside of the quartz tube is under vacuum, isn't that forcing the primary heat transfer from wire to outside (calorimeter) to be via IR? ie. vacuum is a very effective insulator. If so isn't that going to mess up the interpretation of the temperature readings on the surfaces of the quartz tube? ie. thermocouples can read IR directly. To me it makes more sense to leave gas in the tube to promote convective/conductive heat transfer away from the wire and then calibrate the conductive transfer across the glass surface. At steady state conditions the interior heat transfer processes fall out of the energy balance equations and don't matter. electiral in + LENR heat = heat flux across wall of quartz tube. Am I missing something critical here?"
Thanks.
bob
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#433
11 years 9 months ago
trying to understand the basic energy balance
Great to have you mind working with us Bob.
with the multitude of experiments lining up with old and new protocols in new apparatus augmenting the currently running cells in US, we will have a lot of data points.
There will also be experiments
With this regime we are pretty confident of smoking this one out.
Thanks for your kind words
Bob
with the multitude of experiments lining up with old and new protocols in new apparatus augmenting the currently running cells in US, we will have a lot of data points.
There will also be experiments
- Air Flow Calorimetry
- Mass Flow Calorimetry (Fluid)
- Stefan Boltzmann
- Celani 1 & 2 protocols
- Controls
With this regime we are pretty confident of smoking this one out.
Thanks for your kind words
Bob
Last Edit: 11 years 9 months ago by bob.
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#434
11 years 9 months ago
trying to understand the basic energy balance
That is the point,
by being a vacuum, the wire can get to trigger temperature range with much lower power input - 15W instead of 48W or over 100W.
This way - if the wire still outputs the kind of nominal 3-4 W it seams to do at trigger, then the signal is far higher than the noise.
It is true it will all be based on thermalisation of IR - but it will be exactly the same for calibration with unloaded wire and testing with loaded wire - there is no physical change in the apparatus and no confusion from convective and gas type / state effects.
We will be exactly comparing apples with apples - with the only difference being - loaded with Hydrogen.
B
by being a vacuum, the wire can get to trigger temperature range with much lower power input - 15W instead of 48W or over 100W.
This way - if the wire still outputs the kind of nominal 3-4 W it seams to do at trigger, then the signal is far higher than the noise.
It is true it will all be based on thermalisation of IR - but it will be exactly the same for calibration with unloaded wire and testing with loaded wire - there is no physical change in the apparatus and no confusion from convective and gas type / state effects.
We will be exactly comparing apples with apples - with the only difference being - loaded with Hydrogen.
B
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#435
11 years 9 months ago
trying to understand the basic energy balance
What I don't understand is that at steady state all internal convection effects fall out of the energy balance equation and don't matter. If that is the case why not have the best heat transfer from wire to the glass wall. To my thinking you have to eliminate IR transfer out of the cell and force all the heat flux to leave via conduction through the glass. Conduction you can calibrate. IR is really complicated to account for.
If you need higher wire temperatures to achieve the desired LENR trigger then you simply decrease the conductivity of the glass wall. ie. material choice or increase thickness. In fact why does the cylinder need to be glass (other than to see what is going on). Maybe a ceramic cylinder with peep holes would work. Ceramic would presumably kill all IR at the wall as well.
bob
If you need higher wire temperatures to achieve the desired LENR trigger then you simply decrease the conductivity of the glass wall. ie. material choice or increase thickness. In fact why does the cylinder need to be glass (other than to see what is going on). Maybe a ceramic cylinder with peep holes would work. Ceramic would presumably kill all IR at the wall as well.
bob
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#436
11 years 9 months ago
trying to understand the basic energy balance
The New Fire appears to have a burst like nature in many of its variations and is even triggered by non steady states.
We would ideally like to keep the clear cell for later exploration of potential triggering methods, raising temperature and killing gas effects whilst making sure there is no difference between calibration and active run (other than hydrogen in the wire) is something that vacuum enables.
B
We would ideally like to keep the clear cell for later exploration of potential triggering methods, raising temperature and killing gas effects whilst making sure there is no difference between calibration and active run (other than hydrogen in the wire) is something that vacuum enables.
B
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#443
11 years 9 months ago
trying to understand the basic energy balance
What little data I've seen during your runs so far the excess heat is not very bursty by my definition. ie. it lasts for many minutes at sustained levels. You could still get valuable yes/no information for slow transient cases if you looked at integrated (or accumulated) net heat.
kWh electrical in + LENR kWh = kWh heat out
In my opinion the operative variable to measure is the difference between wall temperature on the inside of the glass and the outside. Heat conduction through this solid glass should only depend on this temperature difference provided the thermal conductivity of the glass isn't varying in the temperature range in question. Even that variable can be calibrated out.
If you don't design your apparatus to force all heat to leave via conduction through a solid, then you will be forced into much more complicated calorimeters (eg. gas flow).
At risk of repeating myself the IR thermalization issue is the key here. Glass can transmit some IR wavelengths. A non-trivial amount of heat is likely leaving your apparatus via IR to the ambient. This will be very difficult to calibrate for. If the hydrogen absorption into the coating on the wire is altering the IR spectrum emitted by the hot wire then this could affect the amount of heat leaving by IR. This may show up as a "false" LENR effect which you don't want.
In addition those thermocouples on the glass wall are very poor at measuring accurate temperatures when some IR thermalization is occuring at the fastening point for those thermocouples. Ideally you want those to be shielded from any radiative transfer and only to measure temperature of the solid. In fact the "ideal" placement for the the thermocouples would be for them to be embedded in the glass wall but still separated radially.
That way they have a better chance of reading the actual glass temperature. However as I said earlier in this thread, I think there are better choices for the cylinder than glass. Any IR opaque low thermal conductivity material could work. The lower the thermal conductivity the higher the temperature difference between inside and outside for a give heat flux. ie. the instrument would have better signal to noise.
I think you could design a ceramic tube apparatus with viewport holes for looking at the interior and poking instrumentation into the interior. Ceramics are not transparent to IR.
bob
kWh electrical in + LENR kWh = kWh heat out
In my opinion the operative variable to measure is the difference between wall temperature on the inside of the glass and the outside. Heat conduction through this solid glass should only depend on this temperature difference provided the thermal conductivity of the glass isn't varying in the temperature range in question. Even that variable can be calibrated out.
If you don't design your apparatus to force all heat to leave via conduction through a solid, then you will be forced into much more complicated calorimeters (eg. gas flow).
At risk of repeating myself the IR thermalization issue is the key here. Glass can transmit some IR wavelengths. A non-trivial amount of heat is likely leaving your apparatus via IR to the ambient. This will be very difficult to calibrate for. If the hydrogen absorption into the coating on the wire is altering the IR spectrum emitted by the hot wire then this could affect the amount of heat leaving by IR. This may show up as a "false" LENR effect which you don't want.
In addition those thermocouples on the glass wall are very poor at measuring accurate temperatures when some IR thermalization is occuring at the fastening point for those thermocouples. Ideally you want those to be shielded from any radiative transfer and only to measure temperature of the solid. In fact the "ideal" placement for the the thermocouples would be for them to be embedded in the glass wall but still separated radially.
That way they have a better chance of reading the actual glass temperature. However as I said earlier in this thread, I think there are better choices for the cylinder than glass. Any IR opaque low thermal conductivity material could work. The lower the thermal conductivity the higher the temperature difference between inside and outside for a give heat flux. ie. the instrument would have better signal to noise.
I think you could design a ceramic tube apparatus with viewport holes for looking at the interior and poking instrumentation into the interior. Ceramics are not transparent to IR.
bob
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#444
11 years 9 months ago
trying to understand the basic energy balance
Hi Bob,
Yes, these things have been discussed on our blog and by followers comments for some time now.
We have done an analysis of the IR loss for various glass types and this is published on the blog.
We have also demonstrated that wrapping the cell with metal ( in our case very thin copper sheet) greatly increases temperature.
I think that having a control in 3 of the up and coming experiments will help account for unknowns.
Also, by loading and then 'burning' one cell without loading the control, if there is an effect, we will see what delta it causes and for how long and this will give us an idea of energy density and 'burn' rate and by repeating a number of times it will show how the Hydrogen loading is important. Then if the same is done with the control, this will add further evidence.
The current protocol has so many variables, nearly whatever is done, there are open questions.
Bob
Yes, these things have been discussed on our blog and by followers comments for some time now.
We have done an analysis of the IR loss for various glass types and this is published on the blog.
We have also demonstrated that wrapping the cell with metal ( in our case very thin copper sheet) greatly increases temperature.
I think that having a control in 3 of the up and coming experiments will help account for unknowns.
Also, by loading and then 'burning' one cell without loading the control, if there is an effect, we will see what delta it causes and for how long and this will give us an idea of energy density and 'burn' rate and by repeating a number of times it will show how the Hydrogen loading is important. Then if the same is done with the control, this will add further evidence.
The current protocol has so many variables, nearly whatever is done, there are open questions.
Bob
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#445
11 years 9 months ago
trying to understand the basic energy balance
OK. So wrapping in foil causes large increase in temperature for a given electrical input. This essentially proves that you have large heat transfer by IR transmission through the glass. If that is the case your data is going to very difficult to interpret and you open yourselves to all kinds of valid critiques. It would be a much better apparatus if IR transmission through the glass was eliminated as a heat transfer mechanism to the outside.
What would happen if you placed a foil tube inside your glass tube to reflect IR back inside?
Presumably you could bring the temperature back in line by reducing the electrical energy going in.
I just hate to see you guys spending lots of your precious resources on building calorimeters etc. when if you force all heat to leave via conduction (which is much easier to calibrate) calorimeters are largely uneccessary to prove if heat is being generated internally.
bob
What would happen if you placed a foil tube inside your glass tube to reflect IR back inside?
Presumably you could bring the temperature back in line by reducing the electrical energy going in.
I just hate to see you guys spending lots of your precious resources on building calorimeters etc. when if you force all heat to leave via conduction (which is much easier to calibrate) calorimeters are largely uneccessary to prove if heat is being generated internally.
bob
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