Posted on 01/03/2014 12:25:45 PM PST by thackney
Energy density and the cost, weight, and size of onboard energy storage are important characteristics of fuels for transportation. Fuels that require large, heavy, or expensive storage can reduce the space available to convey people and freight, weigh down a vehicle (making it operate less efficiently), or make it too costly to operate, even after taking account of cheaper fuels. Compared to gasoline and diesel, other options may have more energy per unit weight, but none have more energy per unit volume. On an equivalent energy basis, motor gasoline (which contains up to 10% ethanol) was estimated to account for 99% of light-duty vehicle fuel consumption in 2012. Over half of the remaining 1% was from diesel; all other fuels combined for less than half of 1%. The widespread use of these fuels is largely explained by their energy density and ease of onboard storage, as no other fuels provide more energy within a given unit of volume. The chart above compares energy densities (both per unit volume and per unit weight) for several transportation fuels that are available throughout the United States. The data points represent the energy content per unit volume or weight of the fuels themselves, not including the storage tanks or other equipment that the fuels require. For instance, compressed fuels require heavy storage tanks, while cooled fuels require equipment to maintain low temperatures. Beyond gasoline and diesel, other fuels like compressed propane, ethanol, and methanol offer energy densities per unit volume that are less than gasoline and diesel, and energy densities per unit weight that are less than or equal to that of gasoline. Natural gas, either in liquefied form (LNG) or compressed (CNG), are lighter than gasoline but again have lower densities per unit volume. The same is true for hydrogen fuels, which must be either cooled (down to -253oC) or compressed (to 3,000 to 10,000 psi). However, considering only energy density leaves out the relative fuel economies associated with vehicles capable of using other fuels. The typical fuel economy of an internal combustion engine in a light-duty vehicle is around 25 miles per gallon. On an equivalent basis, electric vehicles with fuel cells powered by hydrogen can double the fuel economy of a similarly sized gasoline vehicle, while battery-powered electric vehicles can achieve a quadrupling of fuel economy, but the costs of fuel cells, hydrogen storage, and batteries are prohibitively expensive to most consumers and the availability of refueling and charging facilities is extremely limited. In addition, the improvement in fuel economy of these vehicles does not compensate for the lower fuel densities of hydrogen and various battery types like lithium ion, lithium polymer, and nickel-metal hydride batteries that result in limited driving range relative to gasoline-powered vehicles.
Sorry, forgot to preview.
Energy density and the cost, weight, and size of onboard energy storage are important characteristics of fuels for transportation. Fuels that require large, heavy, or expensive storage can reduce the space available to convey people and freight, weigh down a vehicle (making it operate less efficiently), or make it too costly to operate, even after taking account of cheaper fuels. Compared to gasoline and diesel, other options may have more energy per unit weight, but none have more energy per unit volume.
On an equivalent energy basis, motor gasoline (which contains up to 10% ethanol) was estimated to account for 99% of light-duty vehicle fuel consumption in 2012. Over half of the remaining 1% was from diesel; all other fuels combined for less than half of 1%. The widespread use of these fuels is largely explained by their energy density and ease of onboard storage, as no other fuels provide more energy within a given unit of volume.
The chart above compares energy densities (both per unit volume and per unit weight) for several transportation fuels that are available throughout the United States. The data points represent the energy content per unit volume or weight of the fuels themselves, not including the storage tanks or other equipment that the fuels require. For instance, compressed fuels require heavy storage tanks, while cooled fuels require equipment to maintain low temperatures.
Beyond gasoline and diesel, other fuels like compressed propane, ethanol, and methanol offer energy densities per unit volume that are less than gasoline and diesel, and energy densities per unit weight that are less than or equal to that of gasoline. Natural gas, either in liquefied form (LNG) or compressed (CNG), are lighter than gasoline but again have lower densities per unit volume. The same is true for hydrogen fuels, which must be either cooled (down to -253oC) or compressed (to 3,000 to 10,000 psi).
However, considering only energy density leaves out the relative fuel economies associated with vehicles capable of using other fuels. The typical fuel economy of an internal combustion engine in a light-duty vehicle is around 25 miles per gallon. On an equivalent basis, electric vehicles with fuel cells powered by hydrogen can double the fuel economy of a similarly sized gasoline vehicle, while battery-powered electric vehicles can achieve a quadrupling of fuel economy, but the costs of fuel cells, hydrogen storage, and batteries are prohibitively expensive to most consumers and the availability of refueling and charging facilities is extremely limited. In addition, the improvement in fuel economy of these vehicles does not compensate for the lower fuel densities of hydrogen and various battery types like lithium ion, lithium polymer, and nickel-metal hydride batteries that result in limited driving range relative to gasoline-powered vehicles.
In other words, gasoline powered vehicles are the best, and using REAL gas instead of that ethanol crap is even better.
Using this as the criteria, diesel would be best.
Hey, don’t stop me, I was on a roll! ;-)
I’m sorry, this is far too complex for Liberals to understand. You are preaching to the choir.
Butanol comes in a close second?..............
“Using this as the criteria, diesel would be best.”
...until you put the tons of EPA-mandated garbage on and around the engine and in the fuel.
No ex-wife/girlfriend jokes please.
Just curious, how would the liquid fuels compare to solid explosives? Can we build an engine that would snatch a tiny piece of a solid explosive, put that in the combustion chamber, and fire away?
Can you imagine the libs’ reaction to that proposal?
Honey, I need to run to the 7-11 to refill my tank with dynamite, do you need me to get the milk?
Explosives aren't all that high energy. For example TNT is only 4.6 megajoules/kg compared to gasoline's 46.4 MJ/kg. The thing with an explosive is that it will release all its energy at once.
I've heard that a block of C4 has the same energy as a block of butter, but I can't a reference to that, and the numbers I just looked up say that butter has a much higher energy density.
“I’m sorry, this is far too complex for Liberals to understand.”
Yup - drama and victimology are in their wheelhouse...physics and chemistry, not so much.
So why didn’t Saturn V burn liquid oxygen and diesel instead of liquid hydrogen?
I’d assume since it’s an airframe they went for light weight.
“Using this as the criteria, diesel would be best.”
Yes, but only with the cat piss injection fluid.
The first stage burned RP-1 and LOX. RP-1 is highly refined kerosene.
That is the way the EPA accepts it, but not the way it would be best.
Cheers!
Happy New Year, Thack
Always enjoy your info from the oil patch.
You’re doing God’s work here.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.