Talk:Energy conversion efficiency

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Antimatter Annihilation

Do we really need this? This is more of a trivial detail. —Preceding unsigned comment added by 98.112.56.22 (talk) 15:40, 1 August 2010 (UTC)[reply]

Reciprocating Steam Engines

Since reciprocating steam engines were largely responsible for the industrial revolution and energy conversion efficiency studies it would be worthwhile to provide accurate values.

Examples - from which to which energy form?

In the examples section, it would be nice to add columns from and to in order to understand exactly, where the energy is lost, e.g. from visible light to electric energy (Solar panel) or from electric energy to mechanical energy (Motor). This might also clear up the misunderstanding about the heat pump which has an efficiency (CoP) of up to a few hundred percent, one may say. I might insert that the next days, if nobody objects. Zeptomoon (talk) 16:09, 19 November 2009 (UTC)[reply]

Examples - efficieny

Please do not change electric heater efficiency to something below 100% All electrical devices convert electric power into heat with absolutely 100% efficiency —Preceding unsigned comment added by 88.118.69.71 (talk) 16:08, 21 February 2011 (UTC)[reply]

Solar cell efficiency

The source PDF for solar cell efficiency mentions 85% in the context "can absorb up to 85% of above-band gap sunlight". There are two additional sources of loss here - lower frequencies of light are lost as heat, and higher frequencies of light are absorbed but only the band-gap potential of the light is converted - the extra energy of the higher frequency photon is also lost as heat. This number should be changed to the highest efficiency that a solar cell has actually achieved from normal sunlight, or it should note that such efficiency requires a monochromatic source. 206.124.146.40 (talk) 02:29, 9 April 2011 (UTC)[reply]

Combustion engine efficiency

The table gives a combustion engine efficiency of 10-50%, based on a broken link. However, the Internal combustion engine article says it's about 18-20% efficient, with a theoretical limit of 37% and one of the sources states that experimental models reach only 28% efficiency. So what is the 10-50% efficiency based on?
Note that the abovementioned source is about cars, but the efficiency is for fuel-to-crankshaft, so that should not matter. Or are car enignes inherently less efficient? However, this is about actual efficiency. If the engine works constantly at the ideal speed, that should improve, but still not come close to 37%, I assume. DirkvdM (talk) 12:54, 21 January 2012 (UTC)[reply]

Efficiency of light sources

The values for different light sources in the table are either wrong or extremely misleading. For example: The energy conversion efficiency of any incandescent lamp should be near 100 per cent. Most of it is in the infrared region and thus no benefit to human vision; however, in terms of radiated energy from the filament light bulbs are extremely efficient. The lighting efficiency has nothing to do with energy conversion, but with the physiology of human vision. The details are described in Luminous efficacy. Mixing both up is extremely misleading and very bad style.

Please correct these values so that they give the true energy conversion efficiency (i.e. without mixing up with photometric terms!). For incans, as said above, it should be >90% (the rest is used to heat up bulb and socket, and eventuelly given off as far IR and convective heat), for LEDs and CFLs I would guess something between 20% and 50% (the rest is waste heat inside the electronic components or absorbed by the phosphor and never been radiated off as light/IR/UV). Does anyone more accurate values for this? If not, I suggest to remove the data for light sources, since they are entirely useless in this form.--SiriusB (talk) 12:11, 12 May 2012 (UTC)[reply]

Addition: Someone has cited the article Luminous efficacy but given wrong values. However, neither luminous efficacy nor luminous efficiency is a measure for energy conversion. The former is not even a dimensionless number, while the latter is arbitrarily related to the maximum value of 683 lumens per watt. There is no comparison of output energy with input energy. In the given form it makes about as much sense as specifying the energy conversion efficiency of a PhD student in terms of papers published per calories consumed. In other words, the example of light sources is misleading here.--SiriusB (talk) 19:04, 12 May 2012 (UTC)[reply]

The table is very uninformative

The table should be split in categories for each type of conversion. For example:

electrical to motor
motor to electrical
electrical to heat
luminous to electrical

etc.

"Muscle is 8 to 21% more efficient at natural process energy conversion than photosynthesis" is a very bad kind of sentence and it is what that table is sending as a message 188.254.239.106 (talk)