
I’ve tried to eliminate AC power loads and used inverters to power many AC loads but air conditioning systems remain a significant exception.
My proposed solution is a diesel engine driving a variable displacement hydraulic pump and a hydraulic motor driving an AC generator. The variable displacement pump allows the engine speed to be independent of the generator speed, so engine RPM can vary with loading. A speed controlled hydraulic motor will maintain the AC generator at the required 3600 RPM (60 RPS) and a hydraulic accumulator will dampen out power surges. An additional benefit is that the hydraulic system can directly power other boat systems such as the anchor windlass and davit lifts which typically require very high DC http://www.kynix.com/Detail/669784/DC.html currents.
By making the generator engine and hydraulic pump slightly larger and attaching a hydraulic motor/pump to the main shaft, the generator can double as an auxiliary drive to provide a get home capability and the main engine can power the hydraulics. This eliminates the requirement to run the generator while underway in order to air condition the cabin.
Since the typical battery charger is only 25 amps, using an AC generator to recharge a large battery bank is a very slow process, which contributes to extended periods of generator operation at low loads. To reduce the recharge time, I plan to have a high output alternator such as the Balmar 98-24-220-BL http://www.balmar.net/98dimensions.htm which will produce 200 amps at 3600 RPM and shortens the bulk charge time by a factor of 8. If you wanted to shorten the recharge time further and/or provide an online spare, you could add a second alternator and combine them with the Balmar “Centerfielder” http://www.balmar.net/PDF/Centerfielder.pdf .
Thanks all guys.
Regards;
huale