Developing dieselelectric concepts.

Discussion in 'Hybrid' started by Powerconversion, Jan 30, 2016.

  1. Stumble
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    Stumble Senior Member

    From a recreational perspective my feeling is that if paired with a large battery bank a hybrid DE would be an attractive option. But the system would need to meet a few criteria.

    1) 2/3 power for 1 hour under battery power.
    2) maintain 50% power with a generator indefinatly
    3) comparable weight and size
    4) at least one generator sized to run hotel loads, including all AC's at a reasonable load rate
    5) no more than 2 generators total

    Cost I would pay a premium, but not a lot of one. The silent running and electric drive would be nice, but isn't a huge enticement.
     
  2. philSweet
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    philSweet Senior Member

    #3 is the show stopper for most applications. Footprints are bigger, but headroom may be less, and that can be helpful.

    As a quick estimate for #1, figure your fuel burn in pounds for 2/3 power for 1 hour and multiply by 100. That is the weight in lead batts. The cost to replace the batts will be not a lot less than buying the diesel equal to the lifetime power cycled through the batts. It depends where you are and if you buy fuel by the ton. So if you figure the battery replacement cost as diesel fuel in gallons, you can add that to your generator fuel consumption and get an equivalent fuel efficiency for the system. Doing this really makes you want to minimize battery usage and expense.
     
  3. Powerconversion
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    Powerconversion Junior Member

    1 is not a problem with supercapasitor batterys.
    2 is not a problem.
    3 is not a problem before you want lead battetys because supercapasitors required you to sell both kidneys.
    4 not a problem.
    5 not a problem.

    I think it in reality could be solved in better ways and cheaper. Could run DE with solar panels paralellinh with a diesel and an sterlin Engine. The sterling and solar could provide silent transit at low speeds and diesel could be fired up for manovering and high speed.
     
  4. philSweet
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    philSweet Senior Member

    What would be the point in using supercap batteries in a boat where your peak current isn't much more than your average current? They are usually used for regenerative braking (busses) or dump recharging (trains and trolleys). Their energy is discharged during acceleration or transferred to traction batteries at an appropriate charging rate. They are extremely bulky, like ten times as bulky as a lead battery on an energy basis, they just are able to absorb huge currents effectively, so may be smaller on a current basis. They are basically an addition to the traction battery set, not a replacement. They would only make sense if the battery bank size was being driven by brief peak current requirements instead of capacity. Those currently made for light rail and trolley duty are an expensive part of an expensive system. <<Edit. deleted last sentence and added chart.>>
     

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  5. Stumble
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    Stumble Senior Member

    Pairing solar with propulsion is a terrible idea. Propulsion demands far more power that a reasonable solar panel can supply. Sure you would want to include it, but for a 40' monohull motoring at 2/3 hull speed figure 3-4 days to recharge the battery banks.
     
  6. cmckesson
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    cmckesson Naval Architect

    Yes, these are effectively the characteristics of my hybrid drive, in service on my 36 foot sailboat since 2000. Definitely do-able.

    Chris McKesson
     
  7. Powerconversion
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    Powerconversion Junior Member

    Not if you only want to save fuel(not run off solar alone)
    Correct controllers would always make sure solar penetration is at maximum and any additional load is handled by shore connection or by diesel generator.
    The high tech solar panels just increased it's efficiency past 10% a few years ago, but solar collectors for central heating is around 50% so high efficiency solar panels are still a few years into the future.
     
  8. Powerconversion
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    Powerconversion Junior Member

    Supercapasitors carry more watt-hours per unit of weight. Acid battery's has been around since the bow and arrow was invented while supercapasitors was not even considered an reality until graphene was starting to look like and commercial reality 10years ago. Just like lead acid battery's they will improve both in size, weight and performance. When they do price will crawl down together with improved production methods.
     
  9. philSweet
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    philSweet Senior Member

    No they don't. Look at the Ragone_chart I posted. They are running around 1/5 on a weight basis and worse on a volume basis, and that is comparing them against the most basic wet lead deep cycle batteries. If you needed a bit higher specific power than what lead batts provide, you'd change to better battery chemistries right on up the line to Li-ion, which has 10 times the specific power of lead and 50 times the specific energy of supercaps.

    On the chart I posted, the axis labels are not right. They should read specific energy and specific power, not energy density and power density. But I liked the simplicity of the chart.
     
  10. Stumble
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    Stumble Senior Member

    Actually run the numbers, it has been done over and over here so I won't go through it again, but the reality is that you can't squeeze enough panels of whatever efficiency onto a cruising boat to make up a reasonable proportion of propulsion power. No magic efficency gains or specialized batteries get around the fact that boats take a lot of power to move and solar provides a minimal amount of power per sq foot.
     
  11. cmckesson
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    cmckesson Naval Architect

    I know this group doesn't like my answer, but I'll say it again: Solar panels DO supply the majority of the propulsion power on my monohull cruising sailboat.

    Chris McKesson
     
  12. Powerconversion
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    Powerconversion Junior Member

    No one with minimal technical background would ever claim that solar panels could provide a reasonable proportion of power for propulsion.
    What 1squear meter of solar panel could do is save you for 100liters of diesel fuel a year with today's efficiency levels. It is possible to run a dieselgenerator in paralell with solar power just like running two dieselgenerators together.
     
  13. gonzo
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    gonzo Senior Member

    100 liters is about $50. I think it is hardly worth the extra expense and hassle.
     
  14. Powerconversion
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    Powerconversion Junior Member

    Look at the ragone chart yourself posted. There Supercapasitors are at level with fuel cells regarding energy vs weight and can discharge a lot quicker.

    I think what we disagree about it term supercapasitors. I'm not thinking of double layer capasitors that has been around for 50 years, but graphene based capasitors that has not even been posible to produce until the last few years. If you are interested in technolegy I'm sure graphene is not new to you.
     

  15. Powerconversion
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    Powerconversion Junior Member

    Solar panels need to get higher efficiency and lower price, fuel need to be more expensive. Unless you don't have an environmental agenda it's not worth it for other reasons than satisfy any technical fetish.
     
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