GlennD
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Re: SoCal LEAF & EV Gathering, Y7 - GC in COI - 8 Jul 2017

Fri Jul 07, 2017 6:19 pm

GRA wrote:
garygid wrote:For NG or H2, no matter liquid or gas, the production and distribution chain still appears to be energy use intensive, and likely releases a lot of greenhouse gas to the atmosphere. Solar panels to generate electricity ... seems like a better process to me, and distribution is often already in place. In my Garage, I think H2 and the gas water heater would be a ... bad mix. Even at only 1% per day boil off, it seems like too big of a risk in many garages, underground parking, and in typical service facilities.

Somewhere over in the H2 thread, I provided a link to a study of whether or not H2 could build up to a flammable concentration (4%) in a typical garage given a leak. Even sealing it to a much greater extent than would be the case with a real-world garage (or house FTM), achieving such a concentration was a practical impossibility. Service facilities are even more open. Underground garages may be another matter, but I imagine it all depends on how they're ventilated. Remember, gaseous H2, being such a tiny molecule and lighter than air, will rise and diffuse through just about everything (which is why pure H2 pipelines are so expensive, and they prefer to mix it in low concentrations in NG pipelines). It's not going to pool on the floor.


For sure if LNPG has a venting problem then H2 will also have broblems.

By the way, I saw a red Toyota Muiri in the McDonalds drive through today. From the side it looks OK. IF they could just moderate the UGLY front end. I can see why sales are so slow. People will not buy an ugly car.
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Re: SoCal LEAF & EV Gathering, Y7 - GC in COI - 8 Jul 2017

Sat Jul 08, 2017 1:12 pm

Here's the article I was thinking of:
Dispersion of Permeated Hydrogen in Residential Garages and Assessment of Explosion Hazard for Small Leaks
http://rpsonline.com.sg/proceedings/9789810877248/html/978-981-08-7724-8_07-03.php

Unfortunately, it used to be free to read, but now it's behind a paywall. You can read the abstract, though, which among other things says:
. . . It is argued that the formation of a flammable hydrogen-air mixture as a result of regulated permeation from a hydrogen powered car in residential garages is impossible. The explosion hazard of small leaks able to form flammable hydrogen-air mixture in sealed, or under-ventilated, enclosures is discussed. An overview of the experimental data of different authors confirmed that combustion of initially quiescent lean hydrogen-air mixture without turbulisers in the range of hydrogen concentrations 4-8% by volume produces practically no pressure load that could affect the integrity of the garage structure. . . .
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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garygid
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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 12:10 pm

An almost-sealed garage, with the only vent(s) at floor level on one side, and an "exposed" flame in the water heater ... I would not risk my house by parking a LH2 vehicle, or having a LH2 storage tank, inside the garage.

How many cubic feet of H2 gas are produced by a 10% full LH2 tank/vehicle in 24 hours at 140 degrees F in the garage?

Perhaps they locked the document, perhaps made it Confidential, as one pays, because it is a misleading study. "Impossible" is rarely used in real scientific studies.

Sounds a bit like a "climate change is impossible" study, in my opinion.
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GlennD
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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 2:12 pm

In our LPNG case the only vents with the doors closed were the vented skylights. I think the install area had 3 or 4. Usually the roll up doors were open but when we were closed so were they.

Over three years retired so it is not my problem anymore! Now Long Beach tax payers support me. Paying SSN plus Calpiers was a bitch but in the end it worked out.
2012 Cayenne Red SL traded for:
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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 5:39 pm

garygid wrote:An almost-sealed garage, with the only vent(s) at floor level on one side, and an "exposed" flame in the water heater ... I would not risk my house by parking a LH2 vehicle, or having a LH2 storage tank, inside the garage.

How many cubic feet of H2 gas are produced by a 10% full LH2 tank/vehicle in 24 hours at 140 degrees F in the garage?

Perhaps they locked the document, perhaps made it Confidential, as one pays, because it is a misleading study. "Impossible" is rarely used in real scientific studies.

Sounds a bit like a "climate change is impossible" study, in my opinion.

Not locked, just behinds Elsevier's paywall. I wish I'd copied it when it was still free, but it essentially used a test space sealed off to a level that was physically impossible in a normal garage, and IIRR they were unable to achieve the LFL concentration of 4.1% or anywhere close to it. But if you don't like that one, the other two earlier studies I provided links to are available for free.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 5:59 pm

GlennD wrote:In our LPNG case the only vents with the doors closed were the vented skylights. I think the install area had 3 or 4. Usually the roll up doors were open but when we were closed so were they.

Over three years retired so it is not my problem anymore! Now Long Beach tax payers support me. Paying SSN plus Calpiers was a bitch but in the end it worked out.
The thing is, while experience with NG is useful, it doesn't behave the same as H2. Here's an example of potential modifications to safety codes, from the SF-Breeze LH2 ferry optimization study currently underway:
Sandia is reviewing International Maritime Organization codes for liquid natural gas-powered vessels and developing a technical basis for codes that could be created for hydrogen fuel-cell vessels. Currently, liquid natural gas codes are the closest regulations that can be applied to hydrogen-powered vessels, but they may not accurately represent the properties of hydrogen.

For example, the LNG code requires LNG vessels to have a clearance of 30 feet around all sides of their vents. Hydrogen is lighter than natural gas and much lighter than air, so it does not sink in air like LNG does. Thus, a 30-foot clearance underneath a vent might not be a necessary requirement for a hydrogen ferry, said Sandia Labs mechanical engineer Myra Blaylock, technical lead for the project.

Labs researchers are using computer simulation to explore and analyze four common vent and leak scenarios in which hydrogen could be released on-board vessels to show actual hydrogen behavior. The computational simulations have underlying physics models that have been validated through experiments and allow researchers to confidently explore various scenarios in a quicker and less-expensive way than conducting experimental work for each individual case. The results can be used by the International Maritime Organization to ensure the accuracy of the codes when applied to hydrogen vessels.

See http://www.greencarcongress.com/2017/07 ... andia.html

So, assuming that what would be unsafe with NG is equally unsafe with H2 is probably not accurate. H2 certainly has safety issues, but ISTM the regulatory agencies are proceeding with due caution to see just what the dangers are in real-world exposure to consumers. Which isn't to say that there won't be accidents as people learn more - as the saying goes, safety regs are written in blood. Still, given the negative public perception of H2 safety based on everyone's favorite disaster newsreel from the 1930s (erroneous though the general public's perception of the causes and subsequent injuries/fatalities of that may be), I suspect that most western countries' regulators are being very cautious, because the politicians over them know the public backlash they'll face given even the smallest serious accident involving the public.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 7:29 pm

Just saw this article at GCR, which describes the steps needed for a dealership to work on the fuel cell or H2 tank/lines: http://www.greencarreports.com/news/111 ... t-a-dealer

It's a fairly involved process.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

GlennD
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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Wed Jul 19, 2017 7:30 pm

Given my current lifestyle I could live with a Toyota H2 vehicle. Given Toyota's UGLY front end I think I will stick with my eGolf. You may build a better car but if it is ugly the market will respond.

In my opinion the ugly car is limiting sales. I was one of those that considered the Leaf good. I realize some hated it but everyone hates the Toyota.It is UGLY! No wonder sales are down. I think all current Toyota and Lexus cars are ugly. Who in their right mind would buy a 2018 LS.

One the one hand you have arts and on the other cars. I am not a teen ager. I want something that is understated.
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Re: SoCal LEAF & EV Gathering, Y7 - HTB in SA - 22 Jul 2017

Thu Jul 20, 2017 4:35 pm

GlennD wrote:Given my current lifestyle I could live with a Toyota H2 vehicle. Given Toyota's UGLY front end I think I will stick with my eGolf. You may build a better car but if it is ugly the market will respond.

In my opinion the ugly car is limiting sales. I was one of those that considered the Leaf good. I realize some hated it but everyone hates the Toyota.It is UGLY! No wonder sales are down. I think all current Toyota and Lexus cars are ugly. Who in their right mind would buy a 2018 LS.

One the one hand you have arts and on the other cars. I am not a teen ager. I want something that is understated.

There's no doubt that the Mirai's and to a somewhat lesser extent the Clarity's looks retard sales. Most people have to be willing to get the car(s) in spite of their looks, not because of them.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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garygid
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Re: SoCal LEAF & EV Gathering, HTB - 22 July 2017

Tue Jul 25, 2017 10:45 am

We had a large Gathering, 19 bodies, including 6 ladies, as near as I could count. I know, 2 more and I would have run out of fingers and toes. We stayed more than halfway through the 11 to 4 lunch window, finally clearing out at 2 pm ... probably our longest Gathering.

Thanks all for the many great discussions, and the very caring comradery.

Next Gathering is in 2 weeks, on Aug 5th, at the Golden Corral in the City of Industry. Then, 2 weeks after that, on Aug 19th, back at the Hometown Buffet in Santa Ana.

After that, we slip 3 weeks, to skip Labor Day weekend, as I recall. See this thread's first post for Gathering dates through December.
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2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

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