On 25/11/2020 21:32, Ed Pawlowski wrote:
On 11/25/2020 3:57 PM, Fredxx wrote:
On 25/11/2020 20:33:20, Ed Pawlowski wrote:
On 11/25/2020 2:18 PM, Fredxx wrote:
On 25/11/2020 19:04:18, Ed Pawlowski wrote:

snip

The IC engine is only about 25% to 30% efficient so even generating
with say, 85% efficient fuel use may help overall.

Apart from fuel cells which can be higher than ICEs, what fuel did
you have in mind to have 85% efficiency?

Not so much the fuel but what burns it to power the generator.* Some
boilers can be that efficient.

Lets stop there. Are we talking of boilers or fuel used in association
with prime movers? They are world apart.

I can also assure you some boilers are far higher than that.

No ****, this is just a crude comparison for conversation, not a
comparison of boiler types.


What has a boiler got to do with this?

Boilers make steam that turns generators to make electricity.

It's going from heat to motion that is inefficient.

I really suggest you lookup Carnot and the Second Law of
Thermodynamics before mentioning boiler and transmission in the same
sentence. This might assist in a more complete understanding of
thermal engines:

Not interested in the fine details.* The numbers are just to show that
electricity has the potential to be more efficient.* If you want to do a
full analysis, be my guest, I'll at least look at it.

It's not a matter of fine details. Any heat engine - a device for
converting heat into motion - has a maximum efficiency given by:

1 - (Tc / Th)

where where Tc and Th are the absolute temperatures of the cold and hot
reservoirs, respectively, or

(Th -Tc) / Th

- which amounts to the same thing; so you want the biggest possible
difference in temperatures between the input and output. This is why an
ICE is more efficient than a simple steam engine as the temperatures are
so much more.

Once you've got motion you can convert it into electricity very efficiently.

Heat is a "low grade" energy because it consists of the random motion of
molecules; mechanical (and electrical) energy is "high grade" because it
is directed.

--
Max Demian