Nat gas pressure drop vs. pipe length

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You can easily make a manometer.
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If he has a nat gas furnace he should have all the flow he needs to run the gen. And going with 1" vs 3/4" is only going to cost maybe 20-30 bucks more.
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On Tue, 08 Jan 2013 22:48:51 -0600, Vic Smith

If I wanted to put in one of those insane tankless water heaters AND a range and drier, I would need a bigger meter and inlet line.
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Insane just about sums those things up. Can you imagine if EVERYONE had one of those things, gas or electric? They'd have to re-do the whole infrastructure of the city! Doubtful that they save an iota of energy, altho it would be nice to see objective data. Would make a good thread. Could crosspost to alt.hvac, and see what those greedy asshole prima donnas have to say. LOL
--
EA



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They save a lot of fuel. Because they are only on for a few minutes, they are not likely all to be on at once. They are very common in the UK, don't cause any problem.
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They save a lot of fuel. Because they are only on for a few minutes, they are not likely all to be on at once. ================================================== They would be, between 6 am and 8 am!! And between 4 pm and 7 pm, and 10 pm-12pm.....
The problem is the DEMAND, used in the utility-supplier sense.. The small bitty tankless bathroom sink ditties I see scattered in my workplace are, like, *4 kW*!!!!! I looked up some of the others, and holy shit, we're talking BIG wattage. You can exceed the entire power rating to a house, with just a few of those turned on simultaneously.
And I could see electric tankless being much better than gas tankless, for the same reason that convection ovens are almost always electric --- no wasted exhaust.
I'm sure there are some situations where tankless is appropriate. But I'd have to see real (read: honest) data showing the savings over *properly set-up* conventional stuff.
So I'm not betting the farm that I'm right, just think tankless is a kind of prematurely hyped new technology. Proly time to start a separate thread. :)
--
EA




They are very common in the UK, don't cause any problem.



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The fuel they save is pretty much the standby loss that a tank type would have. Which isn't all that much. I have a typical tank type and my whole gas bill in summer is maybe $17, including the hot water that I used and running the outdoor gas grill.
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The fuel they save is pretty much the standby loss that a tank type would have. Which isn't all that much. I have a typical tank type and my whole gas bill in summer is maybe $17, including the hot water that I used and running the outdoor gas grill. ======================================================== That's right. And if your're comparing gas-to-gas, it's virtual thermodynamic law that massive rapid heating of tankless is going to be inefficient. So at best it will be a wash, and proly a good conventional gas system will be better.
If you're comparing electric to electric, the tankless electric might win, because the energy transfer is 100% in both systems, so the standby losses in the conventional electric water heater would prevail. BUT at the "cost" of hyooge kW demand. And proly the price (ito shit that can go wrong) of greater complexity. Just to wire electric tankless units in can be a big bill.
If you're comparing conventional gas to tankless electric, tankless electric would win efficiency-wise, but might lose overall cost-wise, bec of the higher electric cost. And, again, the complexity. tankless electric has valves, high-power relays, all in a mildly corrosive environment. Again, the hyooge power surges.
Comparing conventional electric with tankless gas, you have a few things at work: in the conventional you have the higher cost of electricity along with standby losses, vs. the raw inefficiency of rapid gas-fired heat transfer. Proly a wash.
An inneresting subject, that ultimately needs controlled conditions. Or some kind of honest consensus. If a dozen people here transferred over to tankless, and every one of them experienced a net overall savings, then I'd say, Wow, I guess the tankless wins.
But I'd be surprised if tankless would win by much, and then there is the longterm "cost to own". Just bec a car is cheaper, or has better mpg's or whatever, doesn't make it cheaper to own.
--
EA



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It's all down to your hot water usage and when you use it. Also relative size of plant. A lot is well oversized and wasteful.
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wrote:

It might not be much but's there 24/7.
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When was Nat Gas connected originally to your house ? How big is the pipe leading to your meter ? My house was built in 53 I just added a high performance kitchen stove. The smallest burner at full power is 20,000 BTU. All I needed was a 1 " connection to the stove if shared, or 3/4" if not I have been replacing all black pipe with 1" flexible hose. I can turn on ALL burners on the stove, with furnace, hot water and dryer running all at once, and I have ample Nat Gas to power everything at capacity.
Also why is a tankless water heater "insane" ? They have been in use in Europe for 40+ years. The modern ones are quite efficient.
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wrote:

They aren't totally insane. Just impractical for most people due to the high cost compared to a tank type. That high cost is not just the unit itself, but the real issue of what is required to install it, eg adequate gas supply. There have been plenty of reports here of needing to upgrade the gas supply line all the way back to the meter, possibly the meter too. Gas supply lines were put in to support what was going into the house plus some future capacity. But a whole house tankless is a large gas load and it's not unusual for the supply to not be adequate. Add it all up, and it could take decades to break even. And you also have the issue that most of them require AC to operate. Basic tank type does not. I had hot water all during Sandy, but no power for a week. The savings are mainly due to elimination of standby losses from the tank type. My whole gas bill in summer is only $17 or so, which includes std pilot type tank water heater and some gas grilling. Obviously the standby issue isn't all that much. And a step up from that is a power vent type, high eff tank unit, which eliminates some of those standby losses.
Now, if you use so much hot water that you run out or have other unique situations, then tankless could be a good fit.
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On Wed, 09 Jan 2013 16:29:41 -0500, snipped-for-privacy@snyder.on.ca wrote:

Always best to check with the utility I guess. I just quickly looked at a tankless heater spec and it wants 3/4" supply and says to check with the utility as to supply from the meter. I have NG furnace, tank water heater, dryer and range/oven. House was built in '59, Chicago suburb. Main feed in the house is a 1 1/2" running to the furnace. Then a double reducer tee, 3/4" straight ahead and 3/4" 90. The 3/4" 90 feeds the furnace, the straight 3/4" has a single reducer tee a bit down the line feeding 1/2" to water heater, then a tee feeding 3/4" upstairs to the upstairs stove, then a final reducer coupling feeding 1/2" to the dryer. I thought it odd there's 3/4" for the upstairs stove, but looking at this chart http://www.kingcounty.gov/healthservices/health/ehs/plumbing/gaspiping.aspx it says a stove uses more BTU than the water heater or dryer. Seems the water heater puts out more flame than the 4 range burners and oven burner combined, but I'm probably just wrong about that. Anyway, everything works fine. And though the inside main line is 1 1/2" the outside gas meter has 1 1/4" in and out. EA should probably should add up the total BTU's he uses and see what the utility says. Then he can address pipe size.
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tankless water heaters have major downsides, some have no hot water in a power failure, during a 3 day power outage a hot shower is very important.....
many areas have regulators at each meter its called a high pressure system.
i have a friend in a low pressure system area, just a single neighborhood regulator....
its always better to a little oversize on supply lines
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Any decent gas line that has been run by a utility to a house will support a 15KW generator. The BTUs are in the range of a large residential gas furnace. Supply is clearly sized to support a lot more than that, because typically you also have water heater, stoves, gas grills, etc.

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wrote:

15Kw is the output. Probably needs around 50Kw or 60Kw gas input on full load
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No shit harry? You figure that out? That it takes more energy in than out?
What a maroon. Has nothing to do with the fact that a typical house has a gas line from the utility more than adequate to run his genset.
harry, what happens when a typical house wants to add a swimming pool? The heater for a swimming pool is 200K to 400K BTUS? You think they have to run a new gas line to the street? Here's a clue. The gas is under higher pressure until it gets to the regulator at the house. It can supply plenty of gas.
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No shit harry? You figure that out? That it takes more energy in than out?
What a maroon. Has nothing to do with the fact that a typical house has a gas line from the utility more than adequate to run his genset.
harry, what happens when a typical house wants to add a swimming pool? The heater for a swimming pool is 200K to 400K BTUS? You think they have to run a new gas line to the street? Here's a clue. The gas is under higher pressure until it gets to the regulator at the house. It can supply plenty of gas. =================================================== I see I'm not the only one you give a hard time to..... LOL
To be fair, not everyone is aware of those kinds of efficiency issues, either, so it was a fair reminder. In fact, most people are not aware of the drastic thermodynamic inefficiencies of heat engines. Makes you wonder about God....
Regarding that residential restriction, yeah, it proly is a rare thing, but it WAS a very inneresting factoid -- unfortunately for the guy who built the furnace.
BUT, it also remains to be seen if my gas service (and piping) can support a gas-fired furnace, kitchen stuff, hot water heater, AND a genset going full tilt -- poss. not at all a moot point during a deep-winter outage. But still, proly not a biggie even if there is a bottleneck somewhere -- things just won't be going 100%.
Also, in my neck of the woods, there is no gas regulator in the house. I don't know if that's good or bad. Mebbe there's one streetside. In fact, I don't ever recall seeing one in the NYC, Westch area -- not that I was looking, but that is something I woulda noticed, house-hunting etc.. Unique to NJ? I know some places have very high water pressure (100 psi), that needs a regulator house-side. That pressure can vary with where you physically are relative to the municipal water pumps.
--
EA



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Besides natural gas are you planning on having other ways you can run it such as having a propane tank installed or something else? ====================================================== Proly just some BBQ type bottles hanging around, more for if for some reason I load the thing onto m'truck. But since I'm now an Oh-ficial Doomsday Prepper (thanks to fuknSandy), I got like 50 gals of gasoline tucked away, so I can always use that. This genset has a separate gas line/filter that you just drop in a gas can -- really nice, as you can set up multiple gas cans siphon-style, for really big capacity. Might also be able to just drop the hose into the gas tank of m'truck!! I'll have to check that out.
Another thing I wanted to do was put a spigot on my gas tank, so I could fill cans right from the truck. Heh, and pray that none of the neighborhood hoodlums know about my gas-tank spigot..... LOL Or, perhaps plumb sumpn in under the hood in the fuel pump line, and just let the fuel pump do the pumping?? I'll have to explore that, see how complicated the wiring would be for that.
Let's put it this way: If an outtage is so bad, so broad that you lose nat gas pressure, we are in *deep shit*. Nat gas almost never goes out. But if it does, that's the neat thing about tri-fuel.
Remember that hyooge blackout, that hit like 1/4 of the US/Northeast?? I wonder if nat gas was lost in that thing.... Fortunately, since it wadn't really storm/disaster related, power came back in about 24 hrs. I think nat gas pressure WAS lost, bec I seem to remember some issues in some buildings, restarting pilots and alladat. Mebbe someone here knows f'sure.
--
EA



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What you actually want is a solid (wood?) burning stove with hotplate (+possibly oven) for cooking and a stock of wood. No-one can then take your fuel supply away/cut it off.
In my house, I can function without electricity.
There will be no petrol, gas,electricity or food after doomsday. But you can relax. The Mayas thing was lies.
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