Radiant Energy collection

[JLanius]

What if you could use gravitational forces to draw all this radiant energy into the small point? If there was some way to create a sufficient gravitational force you would avoid using materials like mirrors (which would absorb some of the energy you are trying to harvest) and get directly to the gathering of this energy.

[habanabasa]

What if you could use gravitational forces to draw all this radiant energy into the small point? If there was some way to create a sufficient gravitational force you would avoid using materials like mirrors (which would absorb some of the energy you are trying to harvest) and get directly to the gathering of this energy.

 

I realize that the mirrors will absorb some of the energy and the amount won't be trivial. The best that I can hope for is a mirror (polished pure silver) that has an emissivity of 0.03. Each reflection therefore will cause 3% of the energy to be absorbed. There will be considerable loss in the trumpet plus the reflections at two mirrors.

 

As to using a gravitational force - The force has to be VERY strong and is way beyond anything that we could even contemplate. The massive gravitational force of the sun bends the pathway of light only slightly. Its effect can be seen during an eclipse when stars that are behind the sun can be seen as if to the side of the sun.

 

mod note: first two posts copied from other thread on this topic

Edited March 22, 2009 by swansont
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[habanabasa]

I would appreciate your considered thoughts on the following -

 

Preamble :

Every surface in the universe radiates and absorbs energy in the form of Electromagnetic waves, provided that the body's temperature is above absolute zero. This is a constantly occurring phenomenon.

The amount of energy emitted is dependent on the temperature of the emitting body, and the rate at which it emits or absorbs is known as its emissivity (measured on a scale of 0 to 1, where 1 would be a perfect absorber / emitter and 0 would be a perfect mirror).

At room temperature (300K), 1 sq m of a perfect emitter will emit approximately 459 watts per sec continuously, 24 hours per day.

Contrast this with sunlight (solar radiant energy) where 1 sq m on a clear day receives in the range of 1000 watts per sec over only about 5 hours.

In other words, there is a significant never ending supply of energy. The difficulty has been in harnessing it.

 

The purpose of this Paper is to discuss a practical method of harnessing usable radiant energy. The device described and others are currently being built.

 

 

Harnessing Radiant Energy

 

John D Jeffery, 17 Springbrook Pde, Idalia, Queensland, 4811 Australia

March 17, 2009

Abstract.

A basic principle is proposed that enables non-solar radiant energy to be harnessed as an energy source. A geometry is described to implement this principle, allowing for the practical harnessing of radiant energy.

 

Introduction: The problem.

Radiant Energy has long been seen as a potential source of unlimited clean and free energy. No method has been found for collecting this energy.

In his 1992 article "NON-SPONTANEOUS RADIATIVE HEAT TRANSFER" * Dr. Sudhir Panse suggested that "small isolated pockets may exist in the Universe, or can be created, in which entropy decreases and heat engines exceed Carnot's efficiency limit". He proposed geometries that might achieve this.

K M Browne's 1993 article "FOCUSSED RADIATION, THE SECOND LAW OF THERMODYNAMICS AND TEMPERATURE MEASUREMENTS” ** was a study in response to S. Panse's paper. He examined two geometries proposed by Panse to focus radiation from objects to heat other objects to a higher temperatures. Browne showed that while the geometries looked functionally correct when the target and emitter were drawn in point form, the situation changed when they were drawn with finite sizes. They did not then achieve Panse's objectives, in that not all of the radiant energy from the emitting body impinged upon a target body of the same size.

 

Browne limited his study to the situation where energy is transmitted between like-sized bodies. He did not examine the possibilities where the bodies were of different sizes.

 

I suggest that the geometries in these cases are such that for all the radiant energy from the now finite-sized emitters to fully impinge upon their targets, the target surface areas must be greater than those of the emitters.

 

The problem is that the larger surface areas of the targets enable them to re-radiate the energy absorbed from the emitters without a discernable change in temperature.

 

 

The solution.

In order for a geometry to cause the target to be raised to a higher temperature, the target surface area must be smaller than that of the emitter, whose total energy is transmitted to the target. Because the temperature of a body increases or decreases until its energy inflow and outflow are equivalent, such a target body, having a smaller surface area than the emitter, would then have an elevated temperature relative to the emitter, as it will be receiving emissions from a larger surface area.

 

I propose that a basic principle of radiant energy collection is:

"For bodies with equivalent emissivities, the emitting surface area of the source of the radiant energy, which is radiated to a target, must be larger than the total emitting surface area of the target".

An example geometry.

I have already discovered a number of geometries that satisfy this basic principle of radiant energy collection. I believe that many more can probably be found.

 

One example of the geometries that I have found uses an internally reflective trumpet mirror, collecting radiant energy from the small end and discharging it from the large end into an elliptical mirror which has a very long distance between the focal points.

 

See figure by clicking this link.

 

The output beam from the trumpet is very complex and I found no convenient way to focus it to a point. My approach to deal with this difficulty, at least in part, is to direct the output from the trumpet toward an elliptical mirror which has a very long focal point separation. The reflection from the mirror near one focal point will be almost parallel as it focusses at the far focal point. The near parallel beam is then intercepted by a parabolic mirror, so giving a small image at the parabolic mirror's focal point (ie the beam is intercepted by the parabolic mirror before it reaches the ellipses far focal point).

 

An elliptical mirror with 40 meters between its focal points was calculated to give a final focussed image of 0.37 mm in diameter. In the calculations below, a focussed image size of 3.0 mm is used.

 

It is assumed that the mirrored surfaces are fully specular, that the ambient temperature is 300K, and that the emissivity of both the emitter and the target is 0.95.

The trumpet has a diameter of 14 mm at its entrance. Assume that the diameter achieved for the final focus is 3.0 mm.

Assume as well that the target has a collection surface area the same size as the final focus and that the target is perfectly insulated and can only radiate through the collection surface area.

 

Area of trumpet entrance (sq mm) = PI * (14/2)2

= 153.938

Area of final image circle (sq mm) = PI * (3.0/2)2

= 7.0686

We use the Stephan-Boltzmann formula to compute the energy radiated.

 

P = e σ T^4

 

Where e is the emissivity of the emitter

σ is the Stephan-Boltzmann constant

= 5.6703 x 10-8 watts / m^2 K^4

T is the Temperature of the emitter in Kelvin

 

Calculate the energy radiated from the emitter into the trumpet.

= 0.95 * (5.6703 x 10-8) * 300^4 *153.938 / 1000000

= 0.0671677 watts / sec

Calculate the ambient energy normally absorbed and radiated by the target.

= 0.95 * (5.6703 x 10-8) * 300^4 *7.0686 / 1000000

= 0.0030842 watts / sec

 

The amount of energy absorbed by the target is

= ambient radiant energy + energy from emitter

= 0.0030842 + 0.0671677 watts / sec

= 0.0702519 watts / sec

 

We rearrange the Stephan-Boltzmann formula to calculate the implied temperature of the target when it reaches equilibrium (at which time it is emitting 0.0702519 watts / sec from an area of 7.0686 sq mm).

 

T = 4√(P/e σ )*area / sq m

 

= 4√{0.0702519 / (0.95 * (5.6703 x 10-8)) / 706.86} * 100K

 

Target Temperature = 655.4K

 

Some of the emissions from the target will be radiated directly back towards the parabolic mirror while a considerable portion will not return to the parabolic mirror as it is radiated into the immediate environment of the target. The re-radiated energy that returns to the parabolic mirror will make its way back to the emitter along the mirror path. The difference between the energy that the target receives from the emitter and that energy that is returned to parabolic mirror is the usable amount of energy at the target end of the device.

 

In conclusion.

Provided that the temperature of the emitters are not altered, devices that conform to the basic principle can be used to produce a constant supply of energy that can be extracted forever from a never ending source.

 

Many more radiant energy harnessing devices can probably be found that will satisfy the basic principle and produce elevated temperatures at their targets. The practicality of these devices will depend largely on their ability to harness the radiant energy from large surface areas and the employment of efficient methodologies to convert the heat differentials between the target and the ambient temperature into usable energy.

 

Contact details

John Jeffery johndjeffery@gmail.com

 

References

* S Panse 1992 J. Phys. D: Appl. Phys. 25 28-31 Non-spontaneous radiative heat transfer.

 

** K M Browne J. Phys. D: Appl. Phys. 26 (1993) 16 - 19, Focused radiation, the second law of thermodynamics and temperature measurements.

[JLanius]

I suggest you take a look at http://www.scienceforums.net/forum/showthread.php?t=39215, which is a similar (mirror-like actually) thread about harnessing this type of energy.

[Klaynos]

The light from the first mirror will not be close to collimated, this will mean that you get nothing like a point focus after the second mirror.

[habanabasa]

I suggest you take a look at http://www.scienceforums.net/forum/showthread.php?t=39215, which is a similar (mirror-like actually) thread about harnessing this type of energy.

 

 

Its my post. I want this to be known as far and wide as possible and have put it onto a number of forums to try and spread the knowledge. I was modifying the text to make it more readable and to make corrections as I went along so each post is slightly different. This was the very first site that I posted on and the original post has the most warts. I think that this is the final product and that there won't be further changes.

 

I had intended to make a device and patent it but soon realized that if I could think of a number of geometries that could do the job then others would as well. So it would be a futile and expensive exercise to patent something that could be bypassed very easily. Remember, you can not patent an idea (the concept), you can only patent the expression of that idea (the devices).

 

There may be a deep problem within what I think I have discovered which will prevent all geometries from working. However, nobody on any of the forums has found it yet. Simply to cite the second law of thermodynamics doesn't cut it with me - I need physical and practical reasons why the principle should not work. I have studied this problem for a very long time and I am unable to find any reason why a properly constructed device will not work as planned.

 

I am hoping that others, who may have more resources than me, will look at this, and realizing the possibilities, proceed with building a working model. I am always open to suggestion and collaboration.

 

There will always be a 'first' to do something. Perhaps some others will make a working device before I finish mine.

 

If I am right and devices can be built to harness radiant energy from this very simple concept then this is a hugely important advance providing the nearest thing to perpetual motion.

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The light from the first mirror will not be close to collimated, this will mean that you get nothing like a point focus after the second mirror.

 

The near parallel beam is then intercepted by a parabolic mirror, so giving a small image at the parabolic mirror's focal point

 

I realize that. I do get a focussed image at the focal point of another ellipse with a relatively short focal separation and a shorter y axis. The image in this instance is not small but is focussed - about the size of the large end of the trumpet. Providing the resulting focused image from the parabolic mirror is small enough then I can have it impinging on a small target. It doesn't have to be a point - just small.

[Klaynos]

How small? Got any numbers? Because if you have you can apply matrix ray optics and work out what the largest source is.

 

Also, you say you want physical reasons why it wont work but not just a citation of the second law, well the second law is a physical reason.

[swansont]

My objections from the previous attempt still stand. You haven't show that you will actually get the stated amount of power out of the trumpet (you treat the open area as a blackbody surface — why?) and you haven't used ray-tracing analysis to show how you get the radiation out of the horn in that manner, or to give you the spot size at the target — you can't focus it to an arbitrarily small size.

 

You didn't even correct your unit mistake from the first thread.

[habanabasa]

How small? Got any numbers? Because if you have you can apply matrix ray optics and work out what the largest source is.

 

An interesting thought - thank you. I hadn't thought of that approach - I am just bumbling along with what I have (an old bent and beaten up trumpet body that I have cut down and polished / silvered the inside). This approach might be very useful when obtaining a larger collector as the amount of energy that I anticipate getting out of my current setup will be minuscule. I am only looking to get a temperature difference to prove the principle.

 

Also, you say you want physical reasons why it wont work but not just a citation of the second law, well the second law is a physical reason.

This is where we have differing views. My understanding of the second law of thermodynamics is that it is a general law based on empirical observation. It is not a law based on calculation or definitive experimentation that covers all eventualities. It is based solely on observation of what has passed to date and hence I have difficulty with your statement that it is in some way physical.

 

Part of what I am attempting to achieve with these posts is to elicit physical, not theoretical, reasons as to why the reader believes the device will not work. Once I have a reason and it is a valid reason, I will be able to determine an appropriate course of action. That course of action might be to abandon the project altogether or to find a way around the problem.

 

To date, after posting on many forums, I have not had even one physical or practical reason why the devices should not work.

 

The principle raises very interesting possibilities with regard to the sourcing and supply of energy in general. In my view, this is of such fundamental importance and has such far reaching consequences that the principle should be examined very carefully and in great detail. My example of a geometry described in the post is just one of many. A flaw in any geometry will not necessarily invalidate the principle. It is the principle itself that must be shown to be invalid in order to debunk the theory.

 

Throughout history scientific laws have been promulgated and changed as new evidence became available. I think that this is one of those times.

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My objections from the previous attempt still stand. You haven't show that you will actually get the stated amount of power out of the trumpet (you treat the open area as a blackbody surface — why?) and you haven't used ray-tracing analysis to show how you get the radiation out of the horn in that manner, or to give you the spot size at the target — you can't focus it to an arbitrarily small size.

 

You didn't even correct your unit mistake from the first thread.

 

Hi again.

 

I am sorry that I didn’t make it clear that the calculated resulting temperature and all that pass in front of it are theoretical values only. I realise that there will be huge losses caused by absorption at the mirrors especially within the trumpet. There will be other losses due to my rickety construction and alignments. It is my hope that I obtain a temperature difference that is greater than the margin of error. In my case that might mean as little as two degrees C. Should I be successful in obtaining a temperature increase at the target then the principle may have been proven in part.

 

I have taken the emissions at the emitter to be from a body with an emissivity of 0.95. This is easily achievable and can be done by placing a cup of material with that emissivity over the trumpet small end (I intend to use marble which has an emissivity of 0.96 to 0.98). I only use the radiant energy emitted from the emitter in the calculation (which is what we are collecting) as the returned radiant energy to the emitter is of no consequence at this time.

 

The emanations from the trumpet are very complex and it is not possible to make standard 2D ray tracing diagrams for them (remember that they are a compression of the random energy that is all about us). However, I have through experimentation with other elliptical mirrors determined how the rays emanate from the trumpet and how they are reflected from the elliptical mirror. Because of this I have been able to come up with a simple 2D representation of the ray paths that occur in 3D. I used this methodology and results from other experiments to determine the path of the rays from the elliptical mirror to the far focal point. The description of the emanations from the trumpet would occupy considerable space on this post and would divert attention from the main focus being the questioning of the ‘principle’ and not how one individual geometry may or may not be presented. That being said, I would be happy to prepare a description and send it to you via PM. The treatment within the trumpet is complex and its output is likewise complex because it comes initially from the random and very complex radiant energy environment around us.

 

The focus size is not arbitrarily. It is obtained by CAD drawing in 2D based on previous knowledge gained. The size obtained from the drawings at 0.37 mm is impossibly small to utilize effectively. Consequently, I determined that I would make a target of 3 mm diameter and adjust the position of the target such that it intercepted the beam from the parabolic mirror before the focal point and at a point where the beam was 3 mm in diameter.

 

A ‘unit’ mistake ? The only thing that I can think of that this might be is the KWH in the preamble which is now changed to watts per second (joules). If I have an error I need to know about it.

 

Thanks.

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I suggest you take a look at http://www.scienceforums.net/forum/showthread.php?t=39215, which is a similar (mirror-like actually) thread about harnessing this type of energy.

 

 

Ooops. I didn't pay attention and didn't realize that the URL points to another thread on this site.

 

That thread was the original which has been updated and changed considerably - for the better I believe. So as not to confuse the questions and answers, that thread was closed and I initiated another with the latest rendition of the post - same post just amended.

[Bignose]

My understanding of the second law of thermodynamics is that it is a general law based on empirical observation. It is not a law based on calculation or definitive experimentation that covers all eventualities.

 

There is plenty of math that backs up the 2nd Law of Thermodynamics. As just one resource, please see Boltzmann's H-Theorem as connected to the statistical mechanics of gases (which is a purely mathematical derivation). There are similar rules that are mathematical derivations in other materials that are not gases, see some of the works by Clifford Truesdell, for example.

 

That, and there are probably literally trillions of examples that follow this law, without a single exception ever being found. Does that mean an exception will never be found? Of course, not. But, I do think that it is very fair to say that it is exceptionally well verified -- both theoretically and empirically. And that it is going to take some very extraordinary evidence to overturn it. The onus is on you to provide that evidence. Otherwise, skepticism for any result that bend or breaks the Second Law of Thermodynamics is very, very well justified.

[morganparkar]

Hi Friend,

 

Gravitation is a natural phenomenon by which objects with mass attract one another.In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. Gravitation compels dispersed matter to coalesce, thus it accounts for the very existence of the Earth, the Sun, and most of the macroscopic objects in the universe.

 

 

Thanks,

 

Parkar

[habanabasa]

There is plenty of math that backs up the 2nd Law of Thermodynamics. As just one resource, please see Boltzmann's H-Theorem as connected to the statistical mechanics of gases (which is a purely mathematical derivation). There are similar rules that are mathematical derivations in other materials that are not gases, see some of the works by Clifford Truesdell, for example.

 

That, and there are probably literally trillions of examples that follow this law, without a single exception ever being found. Does that mean an exception will never be found? Of course, not. But, I do think that it is very fair to say that it is exceptionally well verified -- both theoretically and empirically. And that it is going to take some very extraordinary evidence to overturn it. The onus is on you to provide that evidence. Otherwise, skepticism for any result that bend or breaks the Second Law of Thermodynamics is very, very well justified.

 

Very well said. I will leave this thorny issue to others who are more knowledgeable than myself. They will be able to determine how this new type of geometry will or will not fit with the second law of thermodynamics.

 

I am merely presenting my findings and hypothesis with the primary intent that it becomes public. My secondary agenda is to have it scrutinized by many so that should there be a fundamental problem with the principle, it will come to light quickly. Should a problem be identified that would prevent any of the geometries working then at that time I would have to assess whether to abandon the project or find a workaround. Science has a way of coming up with some results that are not intuitive - a kind of gotcha, so any thing can happen because we are in uncharted territory. So far nothing has been pointed out to me that gives me any concern.

 

The principal argument that I had anticipated was - the target won’t absorb the energy. I do not know for sure what will happen here but for various reasons I expect the energy to be fully absorbed. Other than that I cannot think of anything that worries me.

[swansont]

You have assumed that you will be able to extract a certain amount of power through the horn. Without doing this step of calculating that you actually can do this, you have no theoretical basis to say this will happen.

 

 

 

A ‘unit’ mistake ? The only thing that I can think of that this might be is the KWH in the preamble which is now changed to watts per second (joules). If I have an error I need to know about it.

 

Watts/sec is not a unit of power or energy

[habanabasa]

You have assumed that you will be able to extract a certain amount of power through the horn. Without doing this step of calculating that you actually can do this, you have no theoretical basis to say this will happen.

 

I explained that the energy is collected at the small end of the trumpet.

collecting radiant energy from the small end and discharging it from the large end

I give the diameter of the trumpet at the entrance as 14 mm. I assumed that the ambient temperature is 300K and that emissivity of the emitter is 0.95. This is easily achievable and in practice can be obtained by placing a marble cup (emissivity of marble .96 to .98) over the small end of the trumpet.

Thus using the Stephan-Boltzmann formula I calculated the energy radiated into the small end of the trumpet as joules or watts per second per unit area. I used the second form of the formula because the emitter is not an ideal emitter and therefore I had to include the emissivity of the emitting body in my calculations. These calculations can be seen in my OP.

 

Because the radiant energy reflects off the diverging walls of the trumpet, it is forced to travel towards the large end from where it will be discharged towards the elliptical mirror.

 

Stefan-Boltzmann Law

 

The energy radiated by a blackbody radiator per second per unit area is proportional to the fourth power of the absolute temperature and is given by

For hot objects other than ideal radiators, the law is expressed in the form:

where e is the emissivity of the object (e = 1 for ideal radiator).

 

 

 

Watts/sec is not a unit of power or energy

Please see the above formula which I obtained from the following site http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/stefan.html#c3

 

[insane_alien]

still no Watts/sec on that site.

 

i see calories/sec which is a valid unit of power(although not SI)

[swansont]

as joules or watts per second per unit area.

 

A Watt is a Joule/sec, which makes a Joule = Watt*sec

 

 

Because the radiant energy reflects off the diverging walls of the trumpet, it is forced to travel towards the large end from where it will be discharged towards the elliptical mirror.

 

You have assumed that this will happen, but you have not demonstrated that this is in fact what will happen. As I think I said earlier, this is the difference between science fiction and science.

 

What I expect a careful analysis will show is that a large fraction of the energy will reflect and eventually hit the emitter, even if one were to assume perfect reflection of the walls, and that the emitted energy will not be parallel, which confounds the ability to focus it down to a smaller area. It's a geometry issue, which has been completely glossed over. The devil's in the details.

Edited March 23, 2009 by swansont
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[habanabasa]

A Watt is a Joule/sec, which makes a Joule = Watt*sec

You got me - I missed it and will change the text - thank you. The calculations and results are still correct despite the wrong units being displayed in the process.

 

 

You have assumed that this will happen, but you have not demonstrated that this is in fact what will[i/] happen. As I think I said earlier, this is the difference between science fiction and science.

 

What I expect a careful analysis will show is that a large fraction of the energy will reflect and eventually hit the emitter, even if one were to assume perfect reflection of the walls, and that the emitted energy will not be parallel, which confounds the ability to focus it down to a smaller area. It's a geometry issue, which has been completely glossed over. The devil's in the details.

The movement of radiant energy from the small end to the large end through the trumpet is not assumed. 32 years ago I tried to stuff light down the fat end - that didn't work because the angle of incidence increased with every reflection. Eventually the angle exceeded 90 degrees at which point it started coming back out of the fat end. The converse is true when entering from the small end, the angle of incidence gets smaller with every reflection off the diverging walls.

No energy can be reflected back to the emitter once it has entered the small end. It is a one way street.

As I have said a number of times, the output from the trumpet is very complex however it does focus to a disk off an ellipse. I really didn’t want to explain this here as it has nothing to do with the primary thrust of the article but you are pressing me to do it. It seems that we are getting lost in minutia about this particular geometry when the real issue which can apply to many geometries, namely the proposed basic principle, hasn’t even had a murmur of a question from anyone on any forum. I suggest that this is what should be tackled as it is this that is going to create the furore that I anticipate will come. This is where I really want the questions. The particular geometry used to demonstrate the principle will not be material to the issue as any conforming geometry could be used. In fact this exercise could be done mathematically by completing Browne’s study of Panse’s proposed geometries as it should have been done in 1993 (or by picking your own geometry). I would have preferred to do it mathematically but am prevented by my limited mathematical knowledge. In my view Panse had the answer then, but Browne by doing an incomplete and superficial study ensured that it never got accepted.

 

The focus disk from the ellipse is composed of multiple rings, each of which comes from a different angle of entry to the trumpet. Let me explain - If a parallel beam (the only beam) is aimed at the small end of the trumpet at say 45 degrees from the horizontal relative to the mouth of the trumpet then a focussed image as shown attached will appear. I did this fully expecting to focus to a point. After seeing the image, I was in a funk for about 3 weeks until I worked it out.

What happens is this -

The parallel beams approach the trumpet and impinge on the inside of the trumpet at varying points. Each ray strikes the trumpet at a different point around the circle causing it to have a different angular deflection. The angular deflection causes the rays to contact the wall of the trumpet again where it will again be deflected in the same manner and by so doing will travel in a corkscrew manner down and around the inside of the trumpet. Because the circle drawn where the ray strikes the wall is increasing in size as the ray progresses down through the trumpet, the angle of incidence is decreasing and the ray is deflected each time closer to the wall. The picture shown is a photo of the focussed image of the inside of the trumpet. At some point the rays that entered at this particular angle do not meet the wall of the trumpet and they are beamed out of the trumpet.

Now a description of the output of the trumpet.

Consider the ring ‘of fire’ as it exits the trumpet. Its rays are still progressing from the last reflection forming an expanding cone. Consider a ring drawn at a distance from the trumpet exit where these exiting rays pass through. This second ring is larger than the exit ring. Now we draw the rays between the rings. Pick a point on the smaller ring and connect it with every point on the larger ring. Pick the next point on the smaller ring and likewise connect it to every point on the larger ring. Do this for every point on the smaller ring producing a fairly complex ray pattern. We are only just starting!

Now create a series of rings one inside the other at the exit of the trumpet forming a disk. These are the rings formed by rays approaching the trumpet from all the angles between 0 and 180 degrees. Draw their matching second rings. Repeat the above process of joining the small and large ring for each of the rings in the disk.

Now you have it. You have the mental picture of the output beam from the trumpet. The trumpet has managed to ingest all radiant energy that lands in its entrance and discharge it in a narrower but complex beam that cannot be focussed to a point. However fortunately an elliptical mirror can create an image of all the rings at its second focal point.

 

As you can probably tell, I know my subject and I can assure you, it has been thoroughly researched.

 

Phew! I am glad that that is done.

[Klaynos]

You need some maths, else you've not shown a thing.

[swansont]

No energy can be reflected back to the emitter once it has entered the small end. It is a one way street.

 

This requires that mirrors not be symmetric in how they operate. IOW, you have a mirror where I can see you, but you can't see me. Is that how mirrors really work?

 

Once again, you have assumed behavior that is not consistent with reality.

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As I have said a number of times, the output from the trumpet is very complex however it does focus to a disk off an ellipse. I really didn’t want to explain this here as it has nothing to do with the primary thrust of the article but you are pressing me to do it. It seems that we are getting lost in minutia about this particular geometry when the real issue which can apply to many geometries, namely the proposed basic principle, hasn’t even had a murmur of a question from anyone on any forum. I suggest that this is what should be tackled as it is this that is going to create the furore that I anticipate will come. This is where I really want the questions. The particular geometry used to demonstrate the principle will not be material to the issue as any conforming geometry could be used.

 

It's not minutia. The underlying physics says you will have problems with any geometry (i.e. the basic objection is not about engineering). But you appear to claim that you have demonstrated this, when you say you have focused the light to a disk. Fine — measure the power output.

 

What I suspect has happened is you have collected the fraction of light within some solid angle that can be focused, while the rest has diverged and is not collected. You'll find that the amount of power that you measure is a small fraction of the output, and not what you predict.

[habanabasa]

This requires that mirrors not be symmetric in how they operate. IOW, you have a mirror where I can see you, but you can't see me. Is that how mirrors really work?

 

Once again, you have assumed behavior that is not consistent with reality.

 

What you originally said was -

“What I expect a careful analysis will show is that a large fraction of the energy will reflect and eventually hit the emitter, even if one were to assume perfect reflection of the walls, and that the emitted energy will not be parallel, which confounds the ability to focus it down to a smaller area. It's a geometry issue, which has been completely glossed over. The devil's in the details.”

 

In a nutshell you claim that radiant energy can be reflected back when it enters into a diverging mirror system.

 

That is plainly fatuous nonsense

 

Consider two flat or outwardly curving mirrors that are at one edge nearly joined (the ‘neck’) and at the other they are far apart. Any ray entering the mirrors at the narrow ‘neck’ can only travel away from that point. It is impossible for it to return to the ‘neck’ by reflection off only the two diverging mirrors.

 

I replied and after some explanation said -

“No energy can be reflected back to the emitter once it has entered the small end. It is a one way street.”

This is patently obvious and bears no further explanation other than what is described above.

 

However your recent post needs explanation as there are some basic misconceptions in it. So let us think carefully about it and go all the way through.

 

What is being discussed here is the energy emitted into the trumpet at the small end. This energy is controlled and passed through the mirror system until it impinges on the target. So the target then has ‘seen’ the energy from the emitter.

 

The target emits only some of its energy back towards the parabolic mirror and back through the mirror system to the emitter. The emitter ‘sees’ the lower level of energy from the target.

 

It is true that if you can see me in the mirror then I can see you in the same mirror. What you have not understood is that the rays reflected from your face that travel to my retina are not the same rays that you receive in your retina. What you see, with or without a mirror, are the rays reflected off my face not a return of the rays reflected off your face.

 

 

It's not minutia. The underlying physics says you will have problems with any geometry (i.e. the basic objection is not about engineering). But you appear to claim that you have demonstrated this, when you say you have focused the light to a disk. Fine — measure the power output.

There are a number of points in these statements that need comment.

 

Please provide the underlying physics to support your statement “The underlying physics says you will have problems with any geometry”. I would most certainly be VERY interested in any such underlying physics. To date nobody has even hinted at such a situation.

 

I agree with you - this is not about engineering of any particular geometry but about the basic principle proposed. “(i.e. the basic objection is not about engineering)”.

 

I don’t know where you got the impression that I claim to have demonstrated ‘this’ (The underlying physics says that I will have problems with any geometry!). It would appear from your statement that I also made this claim when I said that I had focussed the light to a disk.

 

I really don’t understand what you are saying. Perhaps you have left something out.

 

As to focussing “the light to a disk”, This has been done previously and I thought it was well explained to you that the image is large. In fact it is larger than the size of the emitter and therefore doesn’t conform to the basic principle of radiant energy collection. Therefore its temperature will not rise no matter how many times I measure it. The whole purpose of this geometry is to create an image that is smaller in surface area than the area of the entrance to the trumpet. In this situation, the temperature of the target will be measured and it is anticipated then to be greater than that of the emitter.

 

 

What I suspect has happened is you have collected the fraction of light within some solid angle that can be focused, while the rest has diverged and is not collected. You'll find that the amount of power that you measure is a small fraction of the output, and not what you predict.

 

This is simply not true. All emissions from the trumpet are seen to impinge on the elliptical mirrors used in the current and prior experiments. (Easy to tell, simply place a piece of paper over the mirror and examine what rays strike the paper, remove the paper to get the reflection).

 

There are none now nor have there ever been spurious rays of light floating around not being collected when I am testing my mirrors. All rays end up at the focus.

 

Therefore your suspicions and suppositions are baseless.

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Merged post follows:

Consecutive posts merged

Sorry no maths, just logic.

 

What sort of maths would that be anyway?

Edited March 24, 2009 by habanabasa
Consecutive posts merged.

[morganparkar]

Hello Friend,

 

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream.

 

Thanks,

 

Parkar

[habanabasa]

An interesting but I think a previously employed idea for a heat exchanger. The principle of passing a fluid with or without additives between two glass panes to collect energy has been done before. One circumstance that comes to mind is the passing of jet fuel through the windshield of very high speed aircraft to keep the windshield cool and to preheat the fuel. Your idea of additives may have some merit though and give your product an edge.

 

Lots of luck with your idea.

[Klaynos]

Well as for maths, all optical systems can be described as a series of mathematical functions, you could work out the energy in, the energy lost at each optic the energy that the absorber at the end actually absorbs, the amount reflected...

 

Also I didn't read your mirror settup you describe, but one of the interesting things about optical systems is that they are reversible, if you just put a mirror at the focus of the final optic (or anywhere if the light is ideally collimated then the path back through the optics will be identical but reversed of that going the other way. There will of course be some losses at each of the optics.

 

Mirrors, detectors and emitters all count as optics when I use the term btw...

[habanabasa]

Well as for maths, all optical systems can be described as a series of mathematical functions, you could work out the energy in, the energy lost at each optic the energy that the absorber at the end actually absorbs, the amount reflected...

 

Also I didn't read your mirror settup you describe, but one of the interesting things about optical systems is that they are reversible, if you just put a mirror at the focus of the final optic (or anywhere if the light is ideally collimated then the path back through the optics will be identical but reversed of that going the other way. There will of course be some losses at each of the optics.

 

Mirrors, detectors and emitters all count as optics when I use the term btw...

 

 

I have looked at this and apart from the simple calculations already in the OP, I don't see a major opportunity for mathematics. It would be nice to be able to calculate the losses however that could entail knowing exactly what the emissivity of the mirrors is and how many reflections there are within the trumpet. Counting the average number of reflections within the trumpet is achievable and it could be a possibility as it is the major source of loss.

 

One other area that has not been mentioned is the re-radiation from the mirrored surfaces. Re-radiation that occurs at the parabolic and elliptical mirrors will have very little effect on the system however re-radiation within the trumpet is a different animal altogether. Re-radiated radiation within the trumpet will be reflected off the walls and because of the diverging nature of those walls, will tend to direct more of it towards the large end of the trumpet and back into the circuit. There will still be a significant quantity that will exit the small end of the trumpet because of the angle at which it is emitted.

 

I am content at this stage to present a logical as opposed to a mathematical model.

[swansont]

What you originally said was -

“What I expect a careful analysis will show is that a large fraction of the energy will reflect and eventually hit the emitter, even if one were to assume perfect reflection of the walls, and that the emitted energy will not be parallel, which confounds the ability to focus it down to a smaller area. It's a geometry issue, which has been completely glossed over. The devil's in the details.”

 

In a nutshell you claim that radiant energy can be reflected back when it enters into a diverging mirror system.

 

That is plainly fatuous nonsense

 

Consider two flat or outwardly curving mirrors that are at one edge nearly joined (the ‘neck’) and at the other they are far apart. Any ray entering the mirrors at the narrow ‘neck’ can only travel away from that point. It is impossible for it to return to the ‘neck’ by reflection off only the two diverging mirrors.

 

No, what I'm saying (in part) is that you can't couple 100% of the light into the diverging mirror system. You are assuming you can — you are only looking at the rays that "enter the neck." A blackbody radiates in all directions — you seem to be assuming that the radiation is already directed into the horn. That's a bad assumption to make.

 

 

There are a number of points in these statements that need comment.

 

Please provide the underlying physics to support your statement “The underlying physics says you will have problems with any geometry”. I would most certainly be VERY interested in any such underlying physics. To date nobody has even hinted at such a situation.

 

Oh yes we/they have. The underlying principle is the second law of thermodynamics. That's why I know it's not something that is a problem with a specific geometry, or can be solved with a better one.

 

 

As to focussing “the light to a disk”, This has been done previously and I thought it was well explained to you that the image is large. In fact it is larger than the size of the emitter and therefore doesn’t conform to the basic principle of radiant energy collection. Therefore its temperature will not rise no matter how many times I measure it. The whole purpose of this geometry is to create an image that is smaller in surface area than the area of the entrance to the trumpet. In this situation, the temperature of the target will be measured and it is anticipated then to be greater than that of the emitter.

 

 

 

 

This is simply not true. All emissions from the trumpet are seen to impinge on the elliptical mirrors used in the current and prior experiments. (Easy to tell, simply place a piece of paper over the mirror and examine what rays strike the paper, remove the paper to get the reflection).

 

There are none now nor have there ever been spurious rays of light floating around not being collected when I am testing my mirrors. All rays end up at the focus.

 

Therefore your suspicions and suppositions are baseless.

 

So the image you get is bigger than the emitter? Which means the light's diverging, something that's been predicted by myself and other posters, and my suspicions are baseless?