American Airlines status

[Red Arrow]

In a sense, you are correct on them being under-sized.  Most are only designed for a 20 to 40 degree rise per pass (at least on the commercial scale I work with not as up on the home units), so, unless you reduce the flow rate, increase your firing rate (BTU's) or recirculate through a small storage tank, you can wind up with a luke warm shower in the middle of winter when you need a delta T of 60 or 70 degrees.

And yes, temperature is part of the calcs for certifying and hydrostatically testing pressure vessels.

I did a brief search on electric tankless water heaters.  The Bosch unit I found has a pretty hefty electric requirement.  The AE125 unit needs 120 amp service at 240/208 V.  This is the larger of the two units shown.  Careful water use would allow use of the smaller unit which only requires 80 Amp service.

The link has some flow rate vs temperature rise info and some typical flow rates for sinks, showers, etc.

http://www.boschhotwater.com/BoschHotWatercomHome/ElectricProducts/PowerStarAE115AE125/FeaturesandSpecs/tabid/397/Default.aspx

[heironymouspasparagus]

As we like to say around my office ASME stands for "Always, Sometimes, Maybe, Except"

Heir, when you are working with a vessel at atmospheric pressure, you are correct, your primary concerns are structural integrity (i.e. the unit doesn't collapse under it's own weight) and durability.  Home water heaters are pressurized.  Different set of rules, but go right ahead and build your own water heater from 18 gauge material.  Oh and use flat heads while you are at it too.

No way!  (Water tanks are pretty thin - kind of like an air compressor tank - same magnitude of pressures - 100 to 250 psi - 'ish).  Anything worth doing is worth overdoing.  Probably use 24" schedule 40 pipe (22.63" ID).  Round end caps.  Got a great welder friend who does a lot of welding for a local company - pressure vessel welding.

Tank;
22.63" dia
72" long
carbon steel @ 55000 psi tensile strength
.69 thick
epoxy line the inside

Will get collapse pressure about 3200 psi.  (External collapse pressure of 1200 psi, without internal gusseting, so part of the house could fall on it without adverse effect).


18 gauge tank would be good for probably 300 psi, but I want massive thermonuclear overkill!

[Conan71]

No way!  (Water tanks are pretty thin - kind of like an air compressor tank - same magnitude of pressures - 100 to 250 psi - 'ish).  Anything worth doing is worth overdoing.  Probably use 24" schedule 40 pipe (22.63" ID).  Round end caps.  Got a great welder friend who does a lot of welding for a local company - pressure vessel welding.

Tank;
22.63" dia
72" long
carbon steel @ 55000 psi tensile strength
.69 thick
epoxy line the inside

Will get collapse pressure about 3200 psi.  (External collapse pressure of 1200 psi, without internal gusseting, so part of the house could fall on it without adverse effect).


18 gauge tank would be good for probably 300 psi, but I want massive thermonuclear overkill!

You apparently didn't see my tongue sticking through my cheek on the suggestion for flat heads.  Use SA516-70 for your material, FYI.

[Red Arrow]

epoxy line the inside

It'll make your water taste funny.

[Conan71]

It'll make your water taste funny.

Does epoxy contain dioxins or BPA?

[heironymouspasparagus]

In a sense, you are correct on them being under-sized.  Most are only designed for a 20 to 40 degree rise per pass (at least on the commercial scale I work with not as up on the home units), so, unless you reduce the flow rate, increase your firing rate (BTU's) or recirculate through a small storage tank, you can wind up with a luke warm shower in the middle of winter when you need a delta T of 60 or 70 degrees.

And yes, temperature is part of the calcs for certifying and hydrostatically testing pressure vessels.

godboko mentioned efficiency - I
n residential, that could make a difference rather than having a tank full of water sitting hot, but I'm kind of thinking a commercial application would see less benefit just because of the duty cycle.  The big savings would/should be for intermittent use - sitting around all day waiting for someone to take a shower versus doing 500 loads of laundry in an 8 hour shift, or washing 1,000 cars per day, or whatever...   I would think a commercial installation would not see much improvement in efficiency over tankless, if no other reason than just because the throughput would be more continuous.  Still gotta 'burn' so many BTU's to get that temperature up.

??


I'm gonna put a solar collector on the roof, too, to give a boost to the tank.

Not sure what liner the water heater people use...they mention the word epoxy, but it could be a kind of ceramic ??.  I guess I could use fiberglass resin.  I don't drink the shower, dishwasher, or washing machine water - at least not most of the time.  Although I have been known to get a wild hair and start making tea with hot water from the tap...just not often.

[heironymouspasparagus]

You apparently didn't see my tongue sticking through my cheek on the suggestion for flat heads.  Use SA516-70 for your material, FYI.

I knew you were kidding.  Have worked with flat heads on a tank type application before, but that tank I described would require probably 8 to 10" of steel for each end.  Plus BIG flanges!  Just use the thin little rounded end caps - no muss, no fuss, it's all good.

FYI, I don't design commercial tanks for anything - that tank I described would be for my own use at normal household water pressure (hopefully well under 200 psi).  Like I said - overkill is your friend!!

[Red Arrow]

Not sure what liner the water heater people use...they mention the word epoxy, but it could be a kind of ceramic ??. 

We haven't had to buy one for a while but we've always bought glass lined water heaters.

[Conan71]

Commercial storage tanks for dorms and gang showers, etc. is a type of concrete lining.  Makes a heavy tank really heavy.

[Townsend]

American Airlines To Relocate Hundreds Of Jobs Out Of Tulsa

http://www.newson6.com/story/15679381/american-airlines-to-relocate-hundreds-of-jobs-out-of-tulsa

TULSA, Oklahoma -- American Airlines announced Wednesday that they will be moving approximately 230 jobs from Tulsa to the Dallas/Fort Worth area.

An airline spokesperson said the move will take place within the next year.

"We believe locating the MOC with the SOC will help make American a stronger, more efficient airline and that's good for all of our employees," said Andrea Huguely, American Airlines Spokesperson.

Local union leaders have said the Tulsa economy would take a $14 million hit if employees relocate.

The airline operates the world's largest maintenance base in Tulsa, with nearly 7,000 employees.

[SXSW]

Hasn't AA added a couple hundred employees at the Tulsa base in the last year or so in a different division?  It sucks for the city that 200+ good jobs are leaving but it's really a wash with the other jobs added, or maybe still a positive for the city (just not a huge positive as it would be if the MOC jobs remained)..

[heironymouspasparagus]

Commercial storage tanks for dorms and gang showers, etc. is a type of concrete lining.  Makes a heavy tank really heavy.

Glad I didn't have to lift one of those into the attic space - the one I got was bad enough!

Glass lined would be good.  Maybe a porcelain process??

[DolfanBob]

American Airlines To Relocate Hundreds Of Jobs Out Of Tulsa

http://www.newson6.com/story/15679381/american-airlines-to-relocate-hundreds-of-jobs-out-of-tulsa

I saw that last night on the news. And point still being. They are relocating your high paying job to Ft Worth, Texas. It's not like they are sending you to Flea Speck, Mississippi. The status could be laid off and tough luck. Is living in Tulsa really worth picketing outside the BOK ? Truth be known. The cost of living in Texas is probably higher so they might just get a raise. And get this. No sales Tax......Bam ! Brush up on the Texican and buy a Cowboys shirt, all is good.

[Hoss]

I saw that last night on the news. And point still being. They are relocating your high paying job to Ft Worth, Texas. It's not like they are sending you to Flea Speck, Mississippi. The status could be laid off and tough luck. Is living in Tulsa really worth picketing outside the BOK ? Truth be known. The cost of living in Texas is probably higher so they might just get a raise. And get this. No sales Tax......Bam ! Brush up on the Texican and buy a Cowboys shirt, all is good.

But they tax the hell out of you to compensate.  I know, I lived there long enough.  Property taxes will kick your donkey there.

[DolfanBob]

But they tax the hell out of you to compensate.  I know, I lived there long enough.  Property taxes will kick your donkey there.

Are car tag's as high there as they are here. And our property Tax in Wagoner County just went up so Im not sure if Oklahoma is catching on to that trick also. Oh and. Real Beer there also. Trust me. I dont like Texas. But my Birth state of Oklahoma is really starting to wear thin with me.