Re: PEM fuel cell efficiency

DE Pauley wrote: 
This is only an indirect answer. MIT has a course on "Application of
Technology" in which fuel cells are analyzed. The 'theoretical' FC
efficiency depends on the load. In slide 9
(http://web.mit.edu/1.149/www/lecture21/lec21slides.pdf) the efficiency
varies from 100% at no load to 50% at full load. In slide 26 the
'typical' efficiency is given as 45%. This probably corresponds to a
range of load conditions encountered during driving, but I am not sure.
A tradeoff for higher efficiency vs larger FC size would be possible.
The optimum may be to increase the size to achieve an efficiency in the
60-75% range.


How can something be 100 percent efficient at no load?
The only possible efficiency at no load would be zero.

--
Many thanks,

Don Lancaster
Synergetics   3860 West First Street  Box 809  Thatcher, AZ 85552
voice: (928)428-4073 email: don@xxxxxxxxxx

Please visit my GURU's LAIR web site at http://www.tinaja.com
.

Relevant Pages

  • Re: [opensuse] Power Supply PSU Efficiency
    ... It very much depends on the power supply in question. ... I looked at a bunch of efficiency plots from 80plus.org. ... They generally peak at 50% of the rated load, ... watt power supply would draw around 470 watts, as it would operate at 85% efficiency. ...
    (SuSE)
  • Re: rotating magnetic field
    ... the unobtainable "holy grail" here would be 0 impedance. ... | voltage is applied to that load. ... The efficiency at this point will be 50% which is lousy. ... At a load of 10 ohms the current will be 0.5 A and the load power will be a maximum at 2.5Watts. ...
    (sci.physics.electromag)
  • Re: Solar Power Satellites
    ... It states that at *maximum power* the resistance in the source and the sink will be equal, thus maximum efficiency in *that* case will be 50%. ... It does NOT follow that maximum efficiency of a generator *in*general* is 50%, most are designed with an internal resistance in the generator much lower than that in the load, this increases the efficiency a lot. ...
    (rec.arts.sf.science)
  • Re: Using a hydrogen fuel cell kit for a science fair?
    ... converting H2 to electricity at each load. ... Find the load which gives best efficiency and figure out ... A thermocouple in the flame gives a few millivolts if you ...
    (sci.energy.hydrogen)
  • Switching Regulator Efficiency vs. Load Current
    ... I'm trying to understand why the efficiency of a switching regulator ... and relative flat when load current is large. ...
    (sci.electronics.design)