What if the textbooks are right?

[CARN0T]

Okay, what if the textbooks are right?---

What if there is NO hidden source of energy, and heat can only be converted to work within the bounds of the second law of thermodynamics?  Then what?

There are a few simple responses to the question--

(1) Not all energy sources are heat sources.  Then, we aren't limited by the Carnot limit.  (No, not mine, silly.)
(2) If it is a heat source, then we can have CHP:  Combined Heat and Power.  If you use all the "waste" heat, to heat your house or something, then there really is no waste.
(3) You can STILL in effect get some extra FREE energy if you raise the efficiency of your engine.  If you double the efficiency of the engine, it's like a "two-for-one" sale-- you pay for the first unit of power and then the second one is "free."  But, you may ask, can we double the efficiency of a common engine, say like the one in the car?  I say the answer is "YES."

Here is the common statement for the Carnot efficiency---

    Eff = 1 - T_L/T_H

This is given in terms of the "High" input temperature and the "Low" output temperature.  For a typical engine, here is a better formula for the Carnot limit--

   Eff = 1 - 1 / R_c^k-1

Here, R_c is the compression ratio.  (For a more accurate formula, you can go to http://www.ernsblog.com.)

The very best car engines today are getting about 30% efficiency.  My analysis indicates that, by very careful design, a 60% efficient car engine is definitely possible.  The first step in getting this greater efficiency is to increase the compression ratio as indicated in the formula above.  But of course this is only the first step.

Ernie Rogers

[WilbyInebriated]

have you ever built an engine?
have you ever modified an engine? such as converting it to run on alcohol or methane?
is this just a paper analysis?

[Magnethos]

ok

[WilbyInebriated]

how does your question address the topic at hand? did you even bother to read his blog? or did you just post some asinine knee jerk reaction?

he has a blog where he says he is currently working on an engine. then if you click on the engine link he says he is planning to start construction. i want to know if he has ever built an engine prior to this attempt or planned attempt.
if you can answer this magnethos, please do. if not, shut up.

[spinner]

Hi, Carnot! Interesting post!

Okay, what if the textbooks are right?---

What if there is NO hidden source of energy, and heat can only be converted to work within the bounds of the second law of thermodynamics?  Then what?

So far, the textbooks ARE right... When dealing with the "Heat", the second Law is THE LAW... Of course, anybody can change it anytime with a decent proof ..

There are a few simple responses to the question--

(1) Not all energy sources are heat sources.  Then, we aren't limited by the Carnot limit.  (No, not mine, silly.)

Yes, not all energy sources are in it's basics a heat source.
A heat source implies a source which is rather low on the scale of the energy origin or quality. But yes, talking about heat source engines, the Carnot type (no, not you, silly!  ) is the limit.

(2) If it is a heat source, then we can have CHP:  Combined Heat and Power.  If you use all the "waste" heat, to heat your house or something, then there really is no waste.

Hmm... Imagine a perfectly insulated house (the one with no heat "losses"). It would be impossible to live in! The radiated heat of it's inhabitants - "bioplants" would cause an unbearable, heat stressed conditions... Luckily (or sadly), this is just theory. We all know by now that a very good heat insulation (realistic!) is a basics for a low energy/cost  living (assuming you live in a moderate or cold areas)...
Combined heat and power? A-HA..!
Tap the heat coming from the tailpipe of your car.... At least 50% of the fuel energy is converted to - heat...
Convert your oil burner & boiler to the diesel engine (using waste heat for heating, and a pure mechanical power for producing an electricity...). The results?

(3) You can STILL in effect get some extra FREE energy if you raise the efficiency of your engine.  If you double the efficiency of the engine, it's like a "two-for-one" sale-- you pay for the first unit of power and then the second one is "free."  But, you may ask, can we double the efficiency of a common engine, say like the one in the car?  I say the answer is "YES."

Here is the common statement for the Carnot efficiency---
    Eff = 1 - T_L/T_H
This is given in terms of the "High" input temperature and the "Low" output temperature.  For a typical engine, here is a better formula for the Carnot limit--

   Eff = 1 - 1 / R_c^k-1
Here, R_c is the compression ratio.  (For a more accurate formula, you can go to http://www.ernsblog.com.)

The very best car engines today are getting about 30% efficiency.  My analysis indicates that, by very careful design, a 60% efficient car engine is definitely possible.  The first step in getting this greater efficiency is to increase the compression ratio as indicated in the formula above.  But of course this is only the first step.

Ernie Rogers

Thanks! You're one of a few ''FE' people who are pointing to THE PROBLEM of heat engines as we know them today... An IC is struggling to overcome 30% (that would be a good diesel type), or maybe 40...50% (...nuclears plants)...

I'm very skeptical about reaching 60% of efficiency with a "carefull design" of an ICE...
There is still a "Carnot limit" >> u=1-Tc/Th, which says efficiency can close to unity when heat difference come close to infinity....
A Deep Space heat drain and a Stars Core source - They provide a >80% Carnot efficiency..!!??  This is so fucked up!


Yep, with an ICE, a compression ratio is one of the keys to improve efficiency. But in realistic engineering terms, this means at least a bit more complicated design... Diesels have normally twice the compression of the petrol types engines.... They're more "robust", (and more close to the limits of the technology)... Try to design an engine, capable of sustaining  10-times the compression of diesels for at least 200 000 km... Hmm...?

Good luck!