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Navy Spends $33 Million For Hybrid of the High Sea
coondoggie writes "Some might call it an enormous floating Prius, but others will call it a step in the right direction: A new hybrid electric engine for US Navy ships that promises to save up to 12,000 barrels of oil a year per ship.
The folks who brought you the Predator unmanned flying aircraft, General Atomics, this week got $32.7 million to develop a proof-of-concept Hybrid Electric Drive (HED) system for a full-scale demonstration on board the Navy's DDG 51 Class destroyers.
DDG 51 destroyers are powered by General Electric gas turbines capable of moving the ships along at over 30 knots or about 35 mph. The General Atomics system would meld into this system and let the ship use electric power for slow-speed maneuvers. The engines would provide more power as the ship needed to go faster."
If 30 tons of Lithium batteries burst open on the high seas? After,say, a torpedo strike?
I bet it would be spectacular.
I would have thought that the Navy would have led hybrid engine research with everything that was done in WWI and WWII for submarines. Essentially those were hybrid engines, with the diesel's powering the boat on the surface and recharging the batteries, and then using the batteries when the ship was submerged.
That has all been supplanted by nuclear submarines, but you have to wonder where battery technology would be today if the Navy had kept using that system.
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You just did. The life expectancy of a Navy ship is along the lines of 30-40 YEARS. As long as the engine doesn't eat it's self and can just be maintained then you will come close to if not completely pay for it's self. Also oil costs dont factor into the cost of physically refueling the ship. Plus if this engine works as planned, it will likely be significantly cheaper to build more since that 33 million rolls in development costs.
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Only $33 million? For a military contract? Really? Not to be a smartass, but that seems insanely cheap for what they're asking for.
Electric drive for low speed is not such a bad thing, especially when conducting passive sonar search. It would make them kind of stealthy, from an acoustic point of view. Antisubmarine Warfare is, after all, an important mission area for Destroyers.
this type of propulsion is already in service in the UK.
in this particular case, the Daring class destroyers also use a combined gas and steam turbine to generate the electric power required for propulsion, thereby improving fuel efficiency.
the interest in electric propulsion is mostly due to other factors, tough: lower heat/sound signature, higher efficiency at slow speed etc.
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Not below cavitation speeds. The overall noise floor is relatively high in the lower portions of the spectrum, given that low frequencies propagate greater distances and are additive. So, signal excess can be low to non-existent for non-cavitating blades. At low speeds engine (and auxiliaries) noise is normally the greater giveaway. Diesel electric boats (submarines, I mean) can be the most challenging targets, for at least as long as they are submerged on batteries. I only know this because I watched Das Boot on TV the other day :)
Actually, there is a mature technology for powering ships with wind. It's called a sail.
My destroyer is like VRRRRRNNN.. VRRRNNNN... VRRRRRRNNNNNN! What does your destroyer sound like?
shhhhhhhhhh
That's cool.
And to further expand on your point, any military should be concerned with fuel efficiency, because a machine that can stay on-station or can hang in a firefight longer has a distinct tactical advantage. Granted, that is but one variable that must be balanced against many others, but it's really just as important as offensive and defensive capabilities.
The loss of both these subs, while tragic, does not change the facts. The point is that neither of these ships were lost due to their reactors, but to other events.
Except that a lot of the sound comes from the propellers alone.
Not in the way you think. The propellers are the point of contact with the sound transmission media - water. The propeller connects with the drive shaft and transmission. The transmission connects with either an electric motor or an engine. And in some cases, multiple engines and/or motors. The vibration and and engine noise is then transmitted through the transmission, the drive shaft, and then propeller, where it is then transmitted into the water for all to hear. This is the primary reason many military vehicles have been heading toward an electric drive system where the ICE is used to turn a generator rather than directly drive the propeller. This is also the reason modern diesel subs have been getting so quite.
In short, the propeller on modern military ships make the vast majority of their noise because they are a transmission point for everything mechanical attached to it, not because its spinning in the water. Which means, using electric motors to spin your propeller, especially at slow speeds can make you incredibly stealthy despite the fact a propeller is still spinning in the water.
Yes, you hear propellers below cavitation speed. Thirty tons of brass doesn't move hundreds of tons of water "quietly". Another sonar operator can hear it from miles away. Standing in after steering, the propellers are quite loud all the time, and very loud any time they make a change in speed. I spent many an hour standing watch in that smelly little room. (and after all that time, I never figured out why it was always so freaking SMELLY!)
So far, I've not seen anyone mention one of the biggest benefits of electric power. Torque. When you flip the switch and/or turn the rheostat, you have power NOW! Gas and diesel are quite slow to build up torque, even in the turbine engines that the Navy uses. Boilers are somewhat better - depending on whether you've already built up a head of steam or not. If not, you're still dependent on turbines spinning up to bring oxygen to the fire. With electrons, there is no perceptible delay.
The result? Sonar hears a torpedo coming in, the port screw is put into full reverse, starboard screw is full forward, and the ship spins (not turns, but spins in place) in about a minute, instead of 4, 5, or 6 minutes.
Alright, today's enemies aren't likely to have torpedos, but the maneuverability can be just as valuable in many other situations - including entering and leaving port when some idiot on a ski boat ignores the rules of the road.
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