Horace writes,
> Jones, *you* should post the data, and do the math. Speculation is easy, but limited in its power to convince anyone. Just because no one has the time at the moment to acquire the data and do the math for every speculation does not mean everyone agrees with them.
Well, achieving universal agreement was certainly not the immediate
aim of an idea which is quite "green" in many ways, but... as for the rough
math, I was just waiting for the proper seque... i.e. someone to propose and
alternative to compare against.
> Since you are engaged in speculating, I'll do a bit of the same. 8^) I'll
> just say that electrolysis can be achieved with higher efficiency than air
> liquefaction. The problem remains hydrogen storage.
OK. Nothing like a challenge. Or as Sir Winston, a man who *should know,*
opined after the Nazi air assault known as the Battle of Britain...
"Nothing is as exhilarating as to be shot at without result."
Let's take it from the "torque" of wind energy to the torque delivered to
the automobile tires, and try to put out some best estimates of which
route is more efficient, hydrogen ( I will grant you that the storage
problem will most likely be solved soon), or CA (cryo-air). To
understand the reason it is CA and not LA would require an appreciation for
local politics in CA.
Anyway at the wind mill itself air can be compressed and then
cooled and recompressed however many times is necessary to give liquid air at an
optimum efficiency of 48 % of the torque. I disagree with Mike that this process
is not as efficient at low air speeds, but someone like Richard who is a pump
expert may be able to correct me, if this is wrong. The same wind-torque can be
used to generate electricity at an optimum efficiency of 95%, and if then used
for electrolysis nearby (w/o line losses), using this electricity to produce
hydrogen will happen at better than 80% ERGO at this stage you have hydrogen at
76% vs. CA at 48%. This seems like a huge advantage, but it is only the
first part of the story.
In the automobile, using hydrogen in a fuel cell can be efficient at low
output - up to 60% if the FC is running at 25% of capacity BUT the FC has a
strong reverse efficiency and at 90% usage capacity, the efficiency is less than
50%. For comparison, according to Knowlen and Williams, from the Aerospace and
Energetics Research Program, University of Washington in "Quasi-Isothermal
Expansion Engines for Liquid Nitrogen Automotive Propulsion" they conclude:
"The potential for utilizing the available energy of liquid nitrogen for
automotive propulsion looks very promising. Heat transfer calculations of a
quasi-isothermal reciprocating engine that has a heater core imbedded within its
expansion chamber indicate that nearly 85% of the performance of an ideal
isothermal power cycle can be attained.
Now we are getting down to "brass tacks, no?
1)In this corner, Hydrogen 50% of 76% = 38% so far but this is not
net torque, so then one must restate this by the electric motor
inefficiency so lets say it becomes 35% net from wind-to-road.
2) In this corner CA where you have 85% of 48%, or over 40%... PLUS this is
torque to the wheels
Preliminary decisions of the judges: CA is at least 10% more efficient
torque-to-torque than is H2.
Care to challenge the court-side ruling or to add your own spin on the
numbers?
Jones
