Variable Speed Diesel Generators - Available Late Summer 2015
GENESI VARIABLE SPEED GENERATOR FOR STAND ALONE OR GRID CONNECTION
Genesi an evolution of the concept of power generation
Energy efficiency is a major concern now days and there are now several product out in the market developed specifically to reduce the fuel consumption and carbon footprint of traditional generators, but do they really deal with the key issues, Hybrid systems which basically combine a diesel generator with an inverter go in some part to helping improve the situation, but you are still relying on a fixed speed diesel engine to drive the generator and inverters are simply large storage vessels for additional energy and that energy has to come from somewhere, whether it be recharged from the grid or from the fixed speed generator. In reality what they do offer is the option to be able to turn the generator off during periods of light load, which will save fuel to a degree and reduce noise levels in sensitive areas particularly at night when demand is usually at its lowest, the question I keep asking though is this really a solution when the fundamental problem is inherent with traditional generator design.
Generators operate at a fixed speed either 1500 rpm or 3000 rpm and the engine size is matched to the continuous rated output of the set, so simplistically a 40kVa generator has a 40kVa engine and that engine, whether you have 5kVa or 40kVa of load will always operate at that fixed speed.
Wouldn’t it be better if you had a generator set that would automatically adjust the engine speed relative to load, so at low load the engine is at idle speed and at full load at full speed and anywhere in between it runs at the optimum speed for the load, so 40kVa 3000rpm, 20kVa 1500rpm, 10kVa 900 rpm, the hybrid systems endeavour to provide a solution for when there are lighter loads, they switch the generator off and take over supply until such times as demand increases or the batteries run low, that’s good, it all helps to save fuel and although I am not convinced as to how effective they really are, help to reduce your carbon footprint. This appears to be a very expensive half measure, these inverters are not cheap.
So is there a better solution, we think so, a true variable speed diesel generator.
Generators are regularly used to power pumps, motors etc. which demand, unless you have invested in soft starts etc. a significant start up current, a 10hp motor direct on line needs a 38kVa generator even though once running 11kVa would be suffice, the reason for this is that a direct on line motor needs up to 7 times its running current to start, alternators as fitted to most generators will only have typically a 2.5 times overload capacity for start-up. So you buy a bigger generator just to get it started, with the variable speed generator what will happen in this scenario is that the engine will switch to full speed for the start-up phase and then return to idle speed whilst it is in operation