Ghideon

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.

The proposed ideas and the links provided speaks in favour of physically impossible devices usually labelled "over-unity". A possible cause, (good point @sethoflagos) : When over unity support creeps into a discussion it is interesting to know if it is due to bad faith argumentation or ignorance regarding physics. I'll postpone my pictures and attempts at a discussion about a simplified system until we know what the agenda is.

If your hypothesis is correct* one consequence is that it allows for less complicated devices to act as heat engines and it also allows for over unity devices**. Since over unity devices / perpetual motion does not exist according to established theories there is a misunderstanding somewhere. Looking at a simpler devices (compared to a complete Stirling engine) may be helpful. (I'll try to fix the missing images later) *) As far as I can understand your hypothesis by reading your comments, reading between the lines and the fact that link to over unity device support is posted. **) @sethoflagos raised a related point already; it might have been lost in all the details about the experiments

I'll try to fix that.

You can for instance neglect friction if the friction is very low compared to other forces. It does not mean friction is exactly zero. It means that the friction is low enough to allow for other forces, more important to the discussion, to dominate. But if you wish to complicate things, feel free to modify my example. It will not change the end result or principles, but likely make the discussion more complicated than necessary. Thanks; I need to update the spelchek on my computer.

Thanks; we assume the device mass to be negligible and friction is neglected. (It is an ideal setup intended to illustrate basic physical principles, not engineering)

Let's try*. An ideally isolated and closed cylinder contains a piston. Insulation is ideal / perfect; no heat can flow in or out of the cylinder or through the piston and no gas can escape the cylinder or pass by the cylinder: Heat is added (for instance through a temporary opening in the perfect insulation: Since the gas in the lower compartment, below the piston, is heated the piston is pushed up. The heat source is removed and perfect isolation is (re)applied. The system is now at rest and will remain so indefinitely since no heat can be transferred in or out or through the cylinder: Ok so far? If so we may move on to the next part. *) I see this as an opportunity to learn; I'm sure expert members will highlight any errors in my attempt.

I would rather say Tom creates some cool experiments and uses a variety of methods and equipment to observe the behaviour of sterling engines under different conditions. But when trying to explain the observed behaviour one can choose to relay on mainstream science or unscientific fringe stuff like Over Unity / Perpetual Motion. If seeking support for the second option on a forum devoted to the first option it should not be too surprising to meet some resistance. I think I grasp where the basic misunderstanding of physics is; I might try to explain if there is some interest.

This could be a suitable label for the video as it is posted in the mainstream section on a scientific forum: Thanks for confirming my suspicions regarding the presented ideas.