The Steel Greenhouse in an Ambient-Temperature Environment
Here is an article by one of SSDDs heroes. Wuwei, here is a good opportunity to pick out the flaws. Post up a handful and we'll see if our thoughts coincide.
An interesting quote- Thermal equilibrium is defined or established when the heat flow between two objects reduces to zero, and the heat flow between two objects is defined as the net difference of the power emitted by either object. It is important to note here that heat is defined only as the net of the difference between the power emissions, and that therefore either power emission by itself is generally not heat. This goes to the quote from Schroeder in “Thermal Physics” (Addison Wesley Longman, 2000) that: “Much of thermodynamics deals with three closely related concepts: temperature, energy, and heat. Much of students’ difficulty with thermodynamics comes from confusing these three concepts with each other.”
I read the article and have a few comments. The writing is agonizingly verbose and awkward.
Equation 3b) is wrong. The background temperature for the sphere's radiation should not be To. It should be Tsh. Because the shell is the surround to the sphere, not the exterior background To.
Equations 4b) to 5b) cascades that error.
Equations 3 and 4 are identical. What's the point of all that verbiage. Very awkward.
Ironically his equation 3b') is a tautology and says nothing about the sphere or shell equilibrium temperature.
In this sentence the author doesn't understand that the shell is a sort of intermediary and floats to an equilibrium somewhere between Tsh and To.
To raise the sphere’s temperature from emission from the shell would require positive heat flow from the shell to the sphere, but this is never possible because at most the shell emits the same power as the sphere.
He doesn't understand that the shell isn't raising any temperature, but is shielding heat output from the sphere. The shell will come to a higher temperature equilibrium.
To raise an object’s temperature requires either work performed on it or heat transferred into it.
That is the same problem the sock puppet skeptics have.
Edit: He assumes an input power to the sphere, Psp. That is a constant and an important part of the system, but it disappears in the rest of his development.
What did you think of the article?
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