So you can have optimum efficiency for propulsion only, at low to midrange revs in a catamaran, when one hull is driven by a diesel and the generated electricity is used to power an electric engine in the other. Is that right?
Exactly what I was thinking. Use this on one diesel in one hull, get about 6kW. For an efficient hulled cat, this could be used for an electric engine in the other hull which could improve the speed (which the diesel is already giving you) by some amount which is hopefully less than the diesel burned to generate the power. It seems that the diesel burn in L/hr is about half the kW (just from a few data points shown). Assuming pretty good efficiency in the alternator, we could hope that generating 6kW wasn’t taking more than say 8kW/13hp from the diesel. For a large diesel, say 100hp, that’s not too much - it’s using say 13hp to run the boat at 5kn by itself at about 2L/hr, the alternator is generating 6kW from another 13hp or 3L/hr (half), which powers an electric motor on the other hull directly which could raise the boat speed to 7kn. So 5L/hr diesel for 7kn speed. This is a bit better than what we currently get, but not enormously. Note that this efficiency is based on direct coupling the alternator to the drive - you’d lose efficiency if you went via a battery. Use solar for the battery instead. While not enormously better efficiency than pure diesel for us, the advantages are there in quietness in one hull, half the maintenance by doing away with the second diesel, and the ability to run electric “only” using the alternator without powering the prop. The diesel is still there for higher speed (still electrically assisted in the other hull, but limited by the alternator). The disadvantage is that the cat would have to run reasonably straight in the offset power situation or the drag from the rudder to fix it will rob you of the overall efficiency.
Can you guys explain how this is measured, and how everything is accounted for? For example how do you measure the kW propulsion load, and how do you measure/calculate the fuel burn total and apportionment between power generation and propulsion? I'm not seeing how the numbers add up in each of the operating scenarios.
The fuel consumption comes from the ecu and is accurate to better than 99%. We measure the electrical output on the DC side after the controller again at better than 99%. Prop load is calculated using the non dimensional curves but is essentially the equation used by propeller designers and is crank load. Using the efficiency curve for the OEG we can again calculate crank load. We now have total crank load and total fuel. One engine, two jobs so the fuel efficiency is the same for propulsion and generation, hence the fuel consumed for each task can be calculated.
@@integrelsolutions3943 So actual load on the prop is not measured, meaning if you are motor-sailing and running the generator these numbers for efficiency are wildly inaccurate.
The engine only turns the prop, and the prop moves the boat. I don’t think the efficiency numbers shown have anything to do with SOG or any dimension of the boat traveling. If the engine is properly loaded by the prop to achieve WOT then you should be able to use the prop manufacturer’s load factor curves along with the electrical energy produced to understand fuel flow and efficiency.
You say that propulsion fuel efficiency with the generator is 50% more efficient and half of what it was without the generator. But you fail to point out that overall fuel consumption is approximately double. So yes, you get a large amount of power generated but at what cost? To make any sense of this you should share a test that shows what level of power your system generates per gram of fuel compared to an out of the showroom boat with a standard engine alternator.
Hi Zeki. Thanks for your comment. We use the generator as a variable load on the main engine, exploiting the fact that, for most of the rev range, the propeller does not apply sufficient load to allow the engine to run at its most fuel efficient. By adding an additional load with the generator, and controlling it in real time, we can pull the total load on the engine close to its optimum, typically about 75% of maximum. As regards overall fuel savings, by loading the engine optimally for most of its rev range we can maintain a specific fuel consumption of about 320g/kWh whether in generator only mode or generator plus propulsion mode. Actual total fuel savings depend on the way in which the boat is used and the efficiency of the generator that we replace but they are significant. Your comment about fuel consumption increasing when the generator load is applied is correct but that fuel is now being burnt much more efficiently. We now have one engine doing two jobs at peak efficiency instead of two engines doing the same amount of work inefficiently. If you have any questions, please do contact us again. We can also send you some graphs which give actual figures on the impact the Integrel system has on fuel economy. Please feel free to find us on Facebook and send us a message. We can then provide these for you. Many thanks
The way I understand this, you’re not getting free work for zero energy. The more work the engine does the more horsepower it needs, and fuel is used to generate horsepower. The difference in having efficiency is a measure of how much fuel is going unburnt out your exhaust. If your engine is 100% efficient then no unburnt fuel is released at the exhaust, it is all used to produce horsepower. The extreme opposite of a good diesel engine is a little radio control airplane where you will see 80%, of the fuel is blown out the exhaust unburned. Therefore the goal of this device is to add variable amounts of electrical generation load onto the engine when you are simply noodling along and the engine is otherwise unloaded, therefore blowing unused fuel or worse, causing Coke formation in the cylinders.
So you can have optimum efficiency for propulsion only, at low to midrange revs in a catamaran, when one hull is driven by a diesel and the generated electricity is used to power an electric engine in the other. Is that right?
Exactly what I was thinking. Use this on one diesel in one hull, get about 6kW.
For an efficient hulled cat, this could be used for an electric engine in the other hull which could improve the speed (which the diesel is already giving you) by some amount which is hopefully less than the diesel burned to generate the power. It seems that the diesel burn in L/hr is about half the kW (just from a few data points shown). Assuming pretty good efficiency in the alternator, we could hope that generating 6kW wasn’t taking more than say 8kW/13hp from the diesel. For a large diesel, say 100hp, that’s not too much - it’s using say 13hp to run the boat at 5kn by itself at about 2L/hr, the alternator is generating 6kW from another 13hp or 3L/hr (half), which powers an electric motor on the other hull directly which could raise the boat speed to 7kn.
So 5L/hr diesel for 7kn speed.
This is a bit better than what we currently get, but not enormously.
Note that this efficiency is based on direct coupling the alternator to the drive - you’d lose efficiency if you went via a battery. Use solar for the battery instead.
While not enormously better efficiency than pure diesel for us, the advantages are there in quietness in one hull, half the maintenance by doing away with the second diesel, and the ability to run electric “only” using the alternator without powering the prop. The diesel is still there for higher speed (still electrically assisted in the other hull, but limited by the alternator).
The disadvantage is that the cat would have to run reasonably straight in the offset power situation or the drag from the rudder to fix it will rob you of the overall efficiency.
That’s a big alternator
Can you guys explain how this is measured, and how everything is accounted for? For example how do you measure the kW propulsion load, and how do you measure/calculate the fuel burn total and apportionment between power generation and propulsion? I'm not seeing how the numbers add up in each of the operating scenarios.
The fuel consumption comes from the ecu and is accurate to better than 99%. We measure the electrical output on the DC side after the controller again at better than 99%. Prop load is calculated using the non dimensional curves but is essentially the equation used by propeller designers and is crank load. Using the efficiency curve for the OEG we can again calculate crank load. We now have total crank load and total fuel. One engine, two jobs so the fuel efficiency is the same for propulsion and generation, hence the fuel consumed for each task can be calculated.
@@integrelsolutions3943
So actual load on the prop is not measured, meaning if you are motor-sailing and running the generator these numbers for efficiency are wildly inaccurate.
The engine only turns the prop, and the prop moves the boat. I don’t think the efficiency numbers shown have anything to do with SOG or any dimension of the boat traveling. If the engine is properly loaded by the prop to achieve WOT then you should be able to use the prop manufacturer’s load factor curves along with the electrical energy produced to understand fuel flow and efficiency.
You say that propulsion fuel efficiency with the generator is 50% more efficient and half of what it was without the generator. But you fail to point out that overall fuel consumption is approximately double. So yes, you get a large amount of power generated but at what cost? To make any sense of this you should share a test that shows what level of power your system generates per gram of fuel compared to an out of the showroom boat with a standard engine alternator.
Hi Zeki. Thanks for your comment.
We use the generator as a variable load on the main engine, exploiting the fact that, for most of the rev range, the propeller does not apply sufficient load to allow the engine to run at its most fuel efficient. By adding an additional load with the generator, and controlling it in real time, we can pull the total load on the engine close to its optimum, typically about 75% of maximum.
As regards overall fuel savings, by loading the engine optimally for most of its rev range we can maintain a specific fuel consumption of about 320g/kWh whether in generator only mode or generator plus propulsion mode. Actual total fuel savings depend on the way in which the boat is used and the efficiency of the generator that we replace but they are significant.
Your comment about fuel consumption increasing when the generator load is applied is correct but that fuel is now being burnt much more efficiently. We now have one engine doing two jobs at peak efficiency instead of two engines doing the same amount of work inefficiently.
If you have any questions, please do contact us again. We can also send you some graphs which give actual figures on the impact the Integrel system has on fuel economy. Please feel free to find us on Facebook and send us a message. We can then provide these for you.
Many thanks
The way I understand this, you’re not getting free work for zero energy. The more work the engine does the more horsepower it needs, and fuel is used to generate horsepower. The difference in having efficiency is a measure of how much fuel is going unburnt out your exhaust. If your engine is 100% efficient then no unburnt fuel is released at the exhaust, it is all used to produce horsepower. The extreme opposite of a good diesel engine is a little radio control airplane where you will see 80%, of the fuel is blown out the exhaust unburned.
Therefore the goal of this device is to add variable amounts of electrical generation load onto the engine when you are simply noodling along and the engine is otherwise unloaded, therefore blowing unused fuel or worse, causing Coke formation in the cylinders.
Buy a tripod.