Intermittency Of Renewables?… Not So Much

[PamW]

9. Litany of scientific ERRORS by kristopher

Last edited Mon Jul 29, 2013, 10:16 AM - Edit history (1)

Once again kristopher is spreading his oft repeated LIE that I am one and the same as another member that was banned from this forum; and he offers the following as "evidence":

http://www.democraticunderground.com/?com=view_post&forum=1127&pid=48646

I have perused this LAME so-called "evidence" and find it to be more of a litany of the scientific ERRORS and MISUNDERSTANDINGS of kristoper.

For example, let's take the following post from the discussion of electric cars vs. internal combustion engines, which contains a quote from kristopher followed by a rebuttal from Dr. Gregory:

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x258338#258993

in which kristopher makes the following statement:

For example, did you know that for our personal transportation fleet, about 80% of the energy in the petroleum fuel doesn't even need to be replaced as it is simply wasted as heat and serves no functional purpose?

ERROR!!! ERROR!! ERROR!!!

The statement above unambiguously shows that kristopher does NOT UNDERSTAND the 2nd Law of Thermodynamics. Waste heat DOES SERVE an important purpose. If kristopher had bothered to attempt to educate himself by following the link that Dr. Gregory provided, he would see, courtesy of the Physics Department at Georgia State University:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html#c2

Second Law of Thermodynamics: It is impossible to extract an amount of heat QH from a hot reservoir and use it all to do work W . Some amount of heat QC must be exhausted to a cold reservoir. This precludes a perfect heat engine.

The heat "QC" is the "waste heat", and the 2nd Law of Thermodynamics says ( as quoted above ) "MUST be exhausted to cold reservoir"

Contrary to kristopher's ill-considered statement, "waste heat" serves a very NECESSARY purpose. (Waste heat serves as the necessary sink for entropy; more on that later)

Evidently, kristopher wants heat engines with no waste heat ( because he doesn't want to replace that portion ), and therefore is proposing a thermodynamic cycle as depicted in the right half of the diagram. That's a thermodynamic cycle in which heat energy "QH" is 100% converted into work "W", which would constitute a "perfect heat engine".

However the Georgia State University Physics Department website states the following about this cycle:

Extracting heat QH and using it all to do work W would constitute a perfect heat engine FORBIDDEN by the second law.

Evidently, kristopher can't fathom the "why" and "how" of the 2nd Law of Thermodynamics.

However, there do exist people with the high intellect and prodigious mental horsepower that CAN fathom the "why" and "how" of the 2nd Law of Thermodynamics. Those people are the Physicists, like those on staff at the national laboratories ( me ), and the Professors of Physics at Universities around the world, and, in particular; at the Physics Department of Georgia State University.

Those physicists say that the "perfect heat engine" envisioned by kristopher is FORBIDDEN by the 2nd Law.

One may not be able to comprehend the "why"; but one should surely be able to understand the implications of the 2nd Law of Thermodynamics when pointed out by University Professors, or their website; which states that the "perfect heat engine" with no waste heat is FORBIDDEN by the 2nd Law of Thermodynamics.

I understand that this doesn't sit well with so-called "progressives", who are always attempting to attain 100% efficiency and eliminate any type of waste. Unfortunately, Mother Nature is NOT a "progressive". She doesn't maintain the same value system that "progressives" do.

Contrary to the wishes and "sensibilities" of "progressives"; the 2nd Law of Thermodynamics imposes an upper limit on the efficiency that can be attained with a heat engine; which is called the "Carnot Efficiency".

In my experience, when confronted with this this scientific truth, the progressives protest, "But I know of heat engines that are rated at 98% efficiency; so how can the 2nd Law of Thermodynamics impose an efficiency limit?"

Here again, the "progressive" is misled by their lack of understanding. When an efficiency of 98% is quoted for a heat engine; that is an isentropic efficiency.

http://en.wikipedia.org/wiki/Steam_turbine

Suppose for the temperature conditions, the Carnot Efficiency was 70%. Scientists and engineers realize that they can not attain heat engine efficiencies that are higher than the Carnot Efficiency. However, they would like a metric as to how close they are to the theoretical maximum. So the "isentropic efficiency" is the actual efficiency divided by the theoretical maximum which is the Carnot Efficiency.

In this case an efficiency that equals the theoretical maximum, would be an isentropic efficiency of 100% In the above case, the heat engine that has an isentropic efficiency of 98% when the Carnot Efficiency is 70%; has an actual efficiency of 68.6% so that it doesn't violate the theoretical maximum.

Still, I often hear the "progressives" make the flawed comparison; "This heat engine has an efficiency of 98%; which is greater than the Carnot Efficiency of 70%; so you are wrong about the Carnot Efficiency being the maximum attainable" ( Everyone see the FLAWED "logic" in the above statement? )

If the 2nd Law of Thermodynamics says that "waste heat" has a purpose; then what is it? In a nutshell; the purpose of the waste heat is to "conserve" entropy. The 1st Law of Thermodynamics is Conservation of Energy tells us that QH = QC + W. That is the energy from the hot reservoir equals the sum of the "waste heat", QC, and the useful work, W.

That isn't enough to uniquely specify the cycle. There's another quantity that must be reckoned with; the entropy. The 2nd Law of Thermodynamics tells us that the entropy is either conserved, or it may increase. The heat engine is most efficient if the entropy is conserved, as opposed to being increased.

Suppose we look at the flow of entropy in kristopher's ill-conceived perfect heat engine with no waste heat. There is entropy associated with the hot reservoir energy QH. There is ZERO entropy associated with the useful work W. If the only thing that happens is that QH is converted to work W; then entropy has been destroyed! That is in strict VIOLATION of the 2nd Law of Thermodynamics; which is why we can NEVER have a heat engine that does what kristopher wants; which is to have no waste heat.

The purpose of the waste heat is to carry off entropy.

In the best possible, most efficient heat engine; the entropy carried off by the waste heat exactly equals the input entropy.

That is why kristopher's statement that waste heat serves no functional purpose is JUST PLAIN 100% WRONG.

That statement merely serves to highlight kristopher's LACK of UNDERSTANDING of the Laws of Physics. Dr. Gregory was COMPLETELY CORRECT on that one.

Or let's take the question of thermal pollution from a solar power plant. The fact that there IS thermal pollution from solar power plants is well known among scientists; but not the general public, as well as many of the denizens of this forum. From an examination of the thread referenced by kristopher, it appears that he and his supporters do not know about the Stefan-Bolzmann Law, and thermal radiation. They believe objects just absorb; and don't radiate. Anyone who has ever seen the view from a FLIR or nightscope has seen the radiant energy from humans. Well, ALL objects radiate depending on their temperature; even those that are not as hot as human bodies. They just radiate at lower frequencies.

So an object placed in the sunlight will not just keep absorbing energy and rising in temperature. An object will reach equilibrium temperature when the rate of energy influx from the sun equals the rate of energy outflux due to both reflection and reradiation:

Solar influx rate = Reflection outflux rate + Reradiation outflux rate

S = (alpha_e) S + b (T_e)^4

where S is the solar energy influx rate, (alpha_e) is the albedo of the environment, and "b" is a factor that includes the Stephan-Boltzmann constant, the surface area,...but the actual value isn't germane to the argument, just the fact that b is positive; b > 0.

Now suppose we put solar cells down over our environment. There are two modifications to the above equation. The albedo changes to (alpha_c), the albedo of a solar collector. Solar collectors are made to be DARK so that they don't reflect the sun's energy. So (alpha_c) < (alpha_e). The other is that there is another way that energy is removed from the system, and that is in the form of electricity. The generation rate will be equal to the product of the efficiency (e_c) of the solar collector and the non-reflected solar influx ( 1 - alpha_c ) S. So for the solar collector, the balance equation for equilibrium is:

S = (alpha_c) S + (e_c)(1 - alpha_c)S + b (T_c)^4

Since both right hand sides equal the solar influx rate, we can set them equal to each other and solve for the difference in reradiation rates which is proportional to the difference in the fourth-powers of the temperatures. Thus we can determine the sign ( + or - ) of the difference between the temperature without the collectors (T_e) and the temperature with the solar collectors (T_c):

b ( (T_c)^4 - (T_e)^4 ) = ( alpha_e - alpha_c - (e_c)( 1 - alpha_c ) ) S

We know that alpha_e > alpha_c; and the efficiency of solar collectors is rather small. So the right hand side of the above equation is positive; which means that T_c > T_e or that the environmental temperature will be HOTTER in the case WITH the solar collectors.

If the reader has a hard time following that; consider the following courtesy of North Carolina State University:

http://www.nc-climate.ncsu.edu/edu/k12/.albedo

OK, progressives; put your "thinking caps" on and follow along. Note the example of putting a black tarp over plants to help keep them warm. The low albedo of the black tarp minimizes the amount of energy reflected away, so it can be used to keep the plants warm. The albedo of a solar collector is also low, because we don't want to reflect energy away; we want to capture it so we have a chance of changing it into electricity. So like the case with the plants, we are capturing MORE energy with either the black tarp or solar collector in place than would be the case if we didn't have either.

Now, if solar collectors were 100% efficient, we would turn all that extra captured solar energy into electricity and send it somewhere else, so it can't thermally pollute our solar collector site. However, solar cells are NOT 100% efficient; they are 20% to 30% efficient. Therefore, 70% - 80% of that extra captured energy is NOT sent offsite, it shows up as waste heat from the solar collector; and is the source of thermal pollution from the solar collector.

Q.E.D. - Dr. Gregory was CORRECT -- AGAIN.

An objective, intelligent examination of the threads cited by kristopher, conclusively shows that Dr. Gregory has the SUPERIOR intellect, the SUPERIOR powers of reason, and the SUPERIOR scientific knowledge.

Now to kristopher's "logic" that concludes that Dr. Gregory and I are one and the same. Evidently, kristoper "thinks" that the principles espoused by Dr. Gregory in the cited posts, and my current posts are just a bunch of right-wing fabrications to denigrate non-dispatchable renewables. Evidently, kristopher believes that only a single person could concoct this particular mix of "right-wing fabrications". Since Dr. Gregory and I both espouse this particular mix of "right-wing fabrications"; then Dr. Gregory and I must be the same person.

The CONCLUSIVELY DEMONSTRATED FLAW in kristopher's "logic" is that these are NOT "right-wing fabrications" to denigrate non-dispatchable renewables. They are, in truth; SCIENTIFIC FACTS.

The reason Dr. Gregory and I sound so similar to kristopher is NOT because we are the same person; but rather, Dr. Gregory and I are evidently BOTH SCIENTISTS. Two SCIENTISTS are going to sound similar because they are both giving you the SCIENTIFIC TRUTH.

What is distressing is that evidently this forum BANNED a scientist merely for speaking the SCIENTIFIC TRUTH.

Now kristopher is calling for me to be banned:

http://www.democraticunderground.com/112748437#post18

"You need to be out of here."

That's not the hallmark of an enlightened group that values diversity!! That's CENSORSHIP.

Kristopher calls it "editorial control".

Is that what the denizens of this forum want; an "editorial control" that sanctions only a pablum of falsehoods; pseudo-science masquerading as real science, and "seasoned" to fit the tastes of progressives; and all that real science is to be DAMNED and BANNED just because you don't "like" it?

Do you know what that sounds like? That sounds like the tactics of CLIMATE DENIERS. They don't like real science either, because it says that they are polluting and/or making money off of polluting. They can't acknowledge that. So they disown and deny the science. Don't we call the climate deniers STUPID and DISHONEST because they don't want what scientists tell them to be in their midst?

So what words do we use for the "flip side" of the coin; people that also want scientists banned; the only difference being a different political agenda. Does having the "correct" political agenda give you a "pass" to engage in anti-scientific censorship?

PamW