Re: Efoy system

by -mojo- Thu Jul 07, 2016 11:16 pm

meanchris wrote:Raises the question, so why can't we buy a...Oh, wait a second:

https://www.victronenergy.com/blog/2014/01/24/new-enerday-fuel-cell/

Now, that might be worth having.

Hmm... that dates from two years ago, so you would think that products would be available by now? But even the smallest are big and heavy - and run really hot internally - so perhaps they are don't scale down small enough for mobile use?

by -mojo- Thu Jul 07, 2016 11:47 pm

-mojo- wrote:Here are a few perhaps more useful numbers which show some comparative figures between methanol and propane:

Cost per kWh (for reference, mains electricity is around £0.16):

Methanol/fuel cell: - £4.50
Propane - £0.60

Energy density:

A litre of methanol yields 1.1kWh
A litre of propane yields 7kWh

And in terms that can be easily visualised, a "typical" propane installation with one 3.9l Calor and one 3.9l backup cylinder would need 50 litres of methanol fuel to be carried for the equivalent energy capacity. Bigger cylinders make the case for gas more attractive, but they are a pain to shift about - though a big underslung tank and a 3.9l backup could be the best of both worlds.

In weight terms, this equates to roughly 20 kilos for gas, and 50 kilos for methanol (assuming that packaging takes the weight up to around 1 kilo per litre).

I should add - to avoid any misunderstanding - that this is not intended as a comparison between methanol and propane when used in fuel cells. It's a simple comparison of the energy yield of a methanol fuel cell versus turning propane straight to heat. A direct comparison of energy content by combustion is that propane has roughly 1.5 times the energy content of methanol, by liquid volume.

If you ~must~ use electricity for energy intensive appliances such as toasters, hairdryers, microwave ovens, etc. then that doesn't help. I guess a more relevant comparison in that case would be the efficiency of a fuel cell versus a petrol generator...

by safariboy Fri Jul 08, 2016 8:10 am

Mojo's calculation is not quite right. Propane should be £0.6 per litre which gives £0.086 per kWHr. I am not sure about methanol cost but the energy density is 4.3 kWh/ litre.
The result is that propane is about half the cost of mains electricity in UK (in Spain more like one fifth!) Diesel works out much the same as propane. ( 1 litre has about twice the density but but costs about half as much. At the moment in UK diesel is a little less than propane. but it varies.

by -mojo- Fri Jul 08, 2016 12:19 pm

safariboy wrote:Mojo's calculation is not quite right. Propane should be £0.6 per litre which gives £0.086 per kWHr.

Well, of course, there is no "right" or "wrong" here. Propane costs whatever you have to pay for it! I based the cost on what it costs me to get a 3.9l Calor cylinder refilled, because that is what is "typically" used in a camper van. Without doubt you can get it much, much cheaper. You can also pay more, depending on quantity, supplier and location.

safariboy wrote:I am not sure about methanol cost but the energy density is 4.3 kWh/ litre.

As I explained, I'm comparing the yield that you get by putting it through an Efoy fuel cell. You may get 4.3 kWh per litre if you burn it, but you don't (according to Efoy's figures on their website, which you can check yourself) if it goes via their system - you get out 1.1 kWh per litre.

by meanchris Fri Jul 08, 2016 12:23 pm

Flippin' 'eck 25% efficiency? You might be better using it to power a steam engine and genny. hugegrins

by steamdrivenandy Fri Jul 08, 2016 12:33 pm

Do they get more efficient as they get bigger?

by Gromit Fri Jul 08, 2016 12:35 pm

-mojo- wrote:In weight terms, this equates to roughly 20 kilos for gas, and 50 kilos for methanol (assuming that packaging takes the weight up to around 1 kilo per litre).

If I needed convincing (which I don't) that alone would do it for me. Who would lug around 50 kilos, when 20 kilos of something much cheaper would provide the same amount of energy, and without the eye watering initial cost???

Vennwood has already said that payload and storage are significant issues ("I realise that with the Worcester we have to compromise not only on payload but also on storage") so it looks as if Mojo has provided the definitive answer. up!

Dave

by Peter Brown Tue Jul 19, 2016 2:26 pm

http://sapiens-project.eu/

Methanol procurement and storage is the Achilles heel of the Efoy fuel cell.

Truma built an LPG fuelled fuel cell and had it at the NEC a couple of years ago. It was massive and expensive so they dropped it before production began.

At the link above you will see that AS were involved in a development project for an LPG fuelled fuel cell for a couple of years but the unit has not yet been developed for commercial production.

efoy - Efoy system - Page 2 WP_000660_zps8qjgqnib

I believe LPG fuel cells have a future in motorhomes but not till the technology gets cheaper. The biggest problem at the moment is removing impurities from the gas.

Peter

by Greyhound Tue Jul 19, 2016 4:11 pm

Agree that once the technology evolves it should become cost effective.

It wasn't that long ago that solar was prohibitively expensive, but now it's an easy and relatively cheap addition to the roof.

by Vennwood Tue Jul 19, 2016 7:54 pm

totally agree here. This has been going on for a number of years but seems to be making little real commercial progress Fingers crossed.