Can a Stirling Engine Withstand Intense Solar Heat without a Coolant?

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Discussion Overview

The discussion revolves around the feasibility of a Stirling engine operating under intense solar heat, specifically focusing on whether it can function without a coolant and the implications of using various materials and fluids in its construction. The scope includes theoretical considerations, engineering challenges, and practical construction advice.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that a Stirling engine can operate using minimal heat sources, such as the heat from a hand, but question the efficiency and practicality of such setups.
  • Concerns are raised about the extreme temperatures within the engine and whether the gas will have sufficient time to cool before re-entering the system, with some proposing the use of heat sinks or water for cooling.
  • One participant inquires about sourcing materials to construct a Stirling engine capable of withstanding high temperatures, such as those required to turn metal red hot.
  • Another participant calculates the potential power output from a focused solar source, estimating around 28,322 watts on a 2" x 2" area, and discusses the implications for engine design.
  • There is a discussion about the choice of working fluid, with some proposing air or nitrogen instead of oil due to fire risks, and questioning the use of lubricants that can withstand high temperatures without igniting.
  • One participant mentions the use of pigmented oil for heat transfer and discusses methods to generate steam without heating the entire mass of fluid.
  • Another participant references historical attempts to use materials like Silicon Carbide for engine components, noting its heat resistance but challenges in machining.

Areas of Agreement / Disagreement

Participants express a range of views on the operation of Stirling engines under intense heat, with no consensus on the necessity of coolant or lubricants, and multiple competing ideas about materials and methods for construction remain unresolved.

Contextual Notes

Participants highlight various assumptions regarding the efficiency of heat transfer, the behavior of gases at high temperatures, and the practical challenges of sourcing materials and constructing the engine. There are unresolved questions about the specific requirements for lubrication and cooling systems.

Who May Find This Useful

Individuals interested in thermodynamics, engine design, solar energy applications, and DIY engineering projects may find this discussion relevant.

douglasg14b
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would a stirling engine work under the heat of 1000 2" x 2" spots of sunlight directed at a single point on its surface? (the point will be a 2" x2" square) and do you need some sort of coolant to lower the heat of the gas you use?
 
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A Stirling engine will work from the heat off of the palm of your hand. You don't get much useful work off of it though.
 
DieCommie said:
A Stirling engine will work from the heat off of the palm of your hand. You don't get much useful work off of it though.

i understand that it will work from any heat souce but the air will eb be extreamly hot in it and will it have time to cool sufficiently before it reenters again? with just a pipe with like heat sinks of do i need water running to cool it?
 
ok and where might a get the materials to make a sterling engine that could withstand enough heat to turn a plate a steal bright red. or turn a pop can into smoke.
 
You could get the materials from a scrap yard, a plumbers' merchant, DIY shop or similar.
 
ok then i ahve been lookign around for effective ways to build a sterling angine but i cannot seem to find anythign reliable. any ideas?
 
At 833 watts per square yard available how many watts do you see going on that 2x2 plate? From there it's an engineering problem. You might want to flow some fluid such as oil with a dark pigment and then risk heat loss when moving it to the stirling.
 
ok then i wold be getting approx-33.32 watts per 2" x 2" plate. and considering i lowered the # on mirrors to about 850 il be getting 28322 watts focused onto a 2" x 2" area.

I managed to figure out how to construct the engine
Another concern of mine is what could i use as a lubricant? i am going to be using regular air and i cannot use oil as a lube because of the chance of it lighting on fire under the heat.

and using oil as the fluid would definitely not work to high of a chance of it lighting in heat piston chamber (I do not think i will be able to remove all the O2 from the chambers as well and do not think oil would expand and contract to what i need)
 
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34 square yards focused on a 2inch square plate. I brought up the pigmented oil as a way to transfer heat to the medium. Put black ink in a cup of water and focus the suns rays with 2 or 3 inch magnifying glass on the surface of the liquid. Instantly the steam generated is condensed and a wisp of water is emitted from the focal point. Point being you do not have to heat the entire mass to make steam. Now you have to figure what to do with it before it cools.

I take it you are not going with a lubricated freon like a car's for the working fluid.
 
  • #10
no i am not. I would be using air, oxygen free air, or nitrogen. I will be using a 2 cylinder engine and have plates of metal sticking out of the "cold" cylinder with water running through them to cool the gas.
 
  • #11
my engine will look similar to this diagram-
 

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  • #12
  • #13
i have spent much time on wikipedia an the Stirling engine page and related articles and pages. and the image is on the url-
http://blog.steamshift.com/wp-content/uploads/moved/stirling_engine.gif

but my main question is do i need a lube and if i do what could i use that can withstand high temperatures and not ignite.
 
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  • #14
Yes I see it now. Silicon Carbide was attempted as an engine block by Smokey Yunick, but he said it was a ***** to machine. Could take a lot of heat with minimal dimension change thus negating the need for a radiator in his car engine application.

As for your lube questions I have to say I am out of my pay grade. Maybe on the engineering section on materials help might come.
 

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