Ghideon

You seem to cherry pick the first picture? What about the picture that show the experiment at a later state?

Good idea. PoE (Power over Ethernet) may also be applicable; one PoE & LAN signal repeater somewhere between house and caravan Personally I prefer a wall jack and a patch cable between wall & equipment.

I disagree, there are too many unknown variables. I don't see how that experiment helps you debunk established theories. I'll take a look at this later!

And without ice as a complicating factor?

One reason for me to ask questions and try to get into the details about your hypotheses and your possible explanations is to find possible improvements in the experiments. For instance if ice was crucial to the experiment I would suggest various ways to get repetitive results from that. If low temperature is the thing that actually is required I intuitively try to simplify how to cool the things instead of how to manage the ice. And maybe if the problem is to get the engines staring when cold side is at ambient temperature that can be managed as well. It all serves to remove variable things that others could have problems to repeat or that may be tricky to reproduce in your setup. None of these requires an explanation of the result before running the experiment but it helps to create a setup that have fewer sources of errors while at the same time does not introduce bias regarding the hypothesis. Why do you have to ask; isn't it obvious since you know thermodynamics? (And I will not try to explain; you asked me not to:)

Thanks for your reply. My intention was to support your comment by adding a scientific example where Carnot terminology was used in what I believed was at the edge of its applicability. Sorry if I misinterpreted and added confusion. I have not (yet) possess the knowledge to comment on the results or methods in the paper. Thanks; that seems to be the point I tried to make by providing the example.

Based on personal experience from my garage; the second law of thermodynamics can be compared to the contents of a spilled assortment box. The contents of the box tend to end up in a disorganized mess. The probability of the contents of the box becoming sorted is low. (Side note: Here is a video describing the statistical aspect of thermodynamics; the description does not rely upon archaic steam engines: https://www.khanacademy.org/test-prep/mcat/chemical-processes/thermodynamics-mcat/v/second-law-of-thermodynamics)

@Tom Booth here is an example where the scientists probe at the limits of applicability: ... Source: https://www.nature.com/articles/nphys3518.pdf (I do not wish to take the discussion off topic, we discuss the case of Carnot limit for macroscopic engines. Just wanted to share in case there is any interest in papers discussing limits of applicability in the context of Studiots comment.)

I''m thinking as an experimenter. When ice is added, for instance under insulation between two engines, I find it complicated to see when all the ice actually melts; I may disturb the experiment. Instead I prefer to use only a thermometer. Thinking again, this is a good idea: What if you instead of ice have a thermometer probe pre-cooled and inserted at the cold side? Then you can see the temperature all the time and the pre-cooled probe takes the role of the ice? If something more massive than the probe is required you can attach the probe to some object of suitable size and shape (The probe may heat too quick when moved from freezer to engine setup). Maybe a thin sheet of metal?

According to established science or your ideas?

The ice just complicates the scenario; would it be possible to discuss an ice-less scenario? I can't follow your descriptions, sorry. Can we agree that you expect a cooling effect on the cold side? I mean, if ice does melt slow in your experiment then, according to your description, the running engine is keeping the temperature lower that ambient at the cold side? If so we can discuss the consequences and a simplified experiment without the errors and failures that the ice will cause.

@Tom Booth did you see my post regarding an addition to the experiment? https://www.scienceforums.net/topic/128644-is-carnot-efficiency-valid/?do=findComment&comment=1228275 (May have been overlooked since there were some x-posting and editing)

Let's outline the logical next step by using one addition. Assume the setup works; We have the Stirling engine running and cold plate insulated with an adjacent Stirling engine or good enough insulation. Place the running engine(s) in a well-insulated box. All the work performed by the engine(s) will be friction loss in the engine or movement of air inside the box. These losses will heat the air inside the insulated box. Conservation of energy means no energy enters or exits the box and no energy is permanently lost in the box, just changing between heat and mechanical work. The running engine(s) keep the cold side cool, and the losses are heating the air. In principle the box is a sealed system, and the engine will never stop since a permanent difference in temperature is established. This goes against my understaning of physics, but it seems to follow logically from your ideas and your conclusion of experiments? Can you provide a reference? It could add value to the discussion. (As far as I know it is ok per forum rules to link to further reading)

The logical consequence of your idea seems to be that you are just one simple component short of creating a major breakthrouh in physics. But I do not believe in such machinery therefore my question was rethorical. But I would be happy to be proven wrong.

Sharing is ok with me but note that my question was a rethorical. Elaborating may take the thread off topic but I’ll clarify if you wish.

Thanks for your comments! I guess proportions are also a concern; a really large piece of ice on a low power engine allows for other factors to have significant impact? Also freezers are maybe not built to precision, hysteresis may allow for the ice to have different temperatures. A few degrees may make a difference when a small engine melts the ice.

That seems reasonable. But under the insulation the temperature will be rather stable once the Stirling engine has run for a while? Temperature will likely vary depending on the load and added heat (and more) but if the effect you propose is there the temperature should read below ambient if the insulation is good enough. Initially it is good enough tho show experimentally, beyond doubt and in a repeatable fashion, that effect you predict exits; exact numbers can be found in later experiments?

I think your (rather long) answers essentially answers my question with "yes, the cold side of the Stirling engine will cool below ambient temperature if sufficiently insulated." Using a thermometer under the isolation on the cold side should be able to show this. Note that if the temperature probe is too large and is made of a material that transfers heat it may disturb the experiment. Recommendation: don't focus too much on ice based experiments unless you have some way to properly control the temperature of the ice. There seem to be many sources of errors which allows for different interpretations and varying outcomes. But you seem to claim that every single engineer* in the whole world the last 200 years are mistaken? *) and scientist, teachers and others...

I did not ask for a complete explanation or theory, just if you had an idea what to look for in the experiment or what to expect; it may trigger new ideas about how and where to measure. I did a quick check* Stirling engines are common among the suppliers of school material so there is at least a market for Stirling engines in education. I do not know the percentage ofd students that perform experiments but it was mandatory when I studied in a tech oriented school (a long time ago). What do you suggest the answer to be? Anyway, it is not withheld, examples from schools are easy to find on google or other search engine of your choice. Possible reasons for the numbers of hits to be limited: -information about minors and their school work may not be freely published online due to local laws. -The topic is not very interesting; I don't for instance see many releases of kids confirming Pythagoras or that their physics task found F=ma to be correct. *) Locally, may not apply globally

Thanks for the reply. some further reasoning about the experiment: Let's again assume one engine, per your initial setup. Insulation is good and we have means to measure the temperature at the cold side and the hot side. At the start the cold side temperature is same as ambient (room) temperature. What should we look for when the engine is started? Is it correct that you predict that the temperature will drop below ambient when engine is running*? Assume the heat added on the hot side is not the maximum what the engine can handle. So therefore we can increase the temperature on hot side . What result do you predict on the cold side? Will the temperature drop further on the cold, isolated side? I ask since this could be easier to measure; we may check the temperature differences and trends and maybe easier get rid of errors. (* I am aware of the implications of this ...)

A quick followup; let's assume the engines cold sides are adjacent (in contact) and that they are insulated (for instance using the materials you proposed early in the thread) so cold side is not disturbed by room temperature. What is your opinion* about the overall efficiency of the combination of two engines versus the sum of the two engines running separated from one another? Do your ideas allow for some additional gain since the two adjacent cold sides "help each other", if I understand you correctly. *) According to your ideas

If you wish to continue the discussion you may want to focus on the experiments instead. If this is still something you want to test, adding heating to the cold side may help in this scenario? I get the impression that your idea* allows for two Stirling engines to be mounted cold plate to cold plate to increase the efficiency of both the engines? *) If correct that is...

Quick note; have you been thinking about adding identical heating elements to both the hot plate and cold sink? A small element under the insulation on the cold side could add control to the temperature difference? I don't mean you should crank up the heat, just add a way to tune the temperature and observe how behaviour depends on temperature. Maybe in combination with the probes you posted above? https://www.scienceforums.net/topic/128644-is-carnot-efficiency-valid/?do=findComment&comment=1227752 (Sorry if this already discussed, I may have missed some nuances of the experimental details)

You believe the screenshot from the video describes how a drinking bird works? You may reduce your confusion by posting references to written material instead of videos. Anyway, your comment highlights some of the issues; the video contains existing things mixed with non-mainstream concepts.

Screenshot from the video @Tom Booth. It would be easier to quote text... You claim the video is based on your ideas and the video promotes devices that are impossible according to established physics.