Quote from: Kirkhill on May 25, 2015, 16:22:55
Prince of Darkness aside >
According to Wiki this is the 45 setup
What I take from that is that it is a Gas Turbine Ship with Electric Drive (2x 21.5 MW (43 MW) driving 2x 20 MW (40 MW) motors) with 4 MW of Gensets that could be used to feed the motors but likely are just going to drive sensors, weapons and ship and hotel loads.
Your power options would be:
1 Motor at 10% of capacity with one Diesel Genset
1 Motor at 20% of capacity with two Diesel Gensets
2 Motors at 10% of capacity with two Diesel Gensets
2 Motors at 50% of capacity with one Turbine
2 Motors at 100% of capacity with two Turbines
I don't know anything about the gas turbines and their cooling requirements but I would imagine a lot of the heat would go up the stack with the flue gases.
A different strategy than the AOPS seems to have adopted with the all diesel solution.
Underway said:
There's quite a good video on the making of the type 45 out there and it shows the GTs in action. It's basically as you say. The GTs kick in when you really need the power.
That is not the way the T45's work.
The GT's are for propulsion, the DG's for shipboard service.
Because it is an integrated electrical system, all power from any source is "dumped" on a "bus" from which everyone draws power. So, in theory, any one of the power sources can provide power to any drawing "client" for that power.
In practice, however, the DG's, even both together, would only let you drag your arse at about 4 knots once the systems and hotel load are taken out. They are an ultimate backup to the GT's, but the are there primarily to provide the ship's service load in harbour or at anchor.
Standard at sea operations is one GT, providing enough power to get up to about 18-19 knots, and one DG providing for the shipboard load (so as to not take GT power away from propulsion) with the second GT kicking in for higher speeds. The second DG is there as the emergency back up for the first DG and to provide for alternating between the two of them.
Having four DG in the AOPS, instead of two DG and two GT, is not a different strategy. Using diesels vs gas turbines is not a "strategy", it's a matter of power. The strategy is having an integrated electrical propulsion system, and it is the same in both cases.
BTW using electric motors on the AOPS for propulsion is in no way indicative of what will be in the CSC's. Using electrical motors on ice capable ships, and particularly ice breakers, is a job requirement: Think about your little 1.5 volt hand held plastic fan. If you stick your hand in it, you'll stop the rotation - remove your finger and it works as if nothing happened. If it was an internal combustion engine spinning it, you would lose your finger. It's the same for operating in ice: If you go over a large ice chunk with the screws of an electric motor ship, the screws will "give" and the electric motors will suddenly draw with greater resistance (causing shipboard brown outs), but it will not break anything and once the ice clears, all will be back to normal. With standard propulsion, something has to give and it won't be the ice. So you will either break/twist a screw or strip gears in the gearbox or worse blow you engine's gasket.