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.
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.
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.
That would be in areas that have those systems. Just go a few miles from here and they have a low pressure distribution system. Guess what do if you want to add more devices? They dig up the existing line and run a larger one.
And even in the case of high pressure distribution systems the regulator and meter are often not large enough to accommodate doubling the gas consumption for say your example. You just simply can't hook into the gas line and hope for the best. There are well known methods and procedures to accommodate additional devices.
Because thats how original gas systems were designed. If you need more capacity they install a bigger line.
You're right. If this project is getting permits and inspections as it should, then all that would be checked out. The fact that it hasn't tells us something. My initial response was not made thinking in the sense that in a power outage every gas appliance is going to be running at the same time. But you're right that you'd want to run a gas furnace and the generator at the same time. The existing service can very likely run either of those at a time, but the 15KW generator itself at full output could be equal to the full load of the furnace and all the other gas appliances together. It's like adding say a whole house on-demand water heater.
But I think if EA wants to do this right, there are a LOT of even bigger issues than the gas service sizing. He's not only asking about gas pipe sizing, but in another thread also asking about sizing and backflow pressure for a long run of exhaust hose that he's going to hook on to this generator. A generator that has been apparently designed to run on tri-fuel, using a Honda gasoline engines. I'll bet we'd agree that this generator is almost certainly sold as a portable, for use outdoors. I'll bet it has no rating for ever being installed indoors, which given the need for exhaust hose, appears to be the intention. If it was rated for indoor installation, I think he wouldn't be here asking about exhaust pipe sizing, backflow pressures, etc., because that would be spec'd along with how to install it. I'll bet the manual for it clearly says it's for outdoor use only.
So, I bet it's illegal as all hell to install it inside in NYC period, because it almost certainly isn't rated for such use. And even if it is legal, I would expect NYC would have some pretty tough code reqts on such an install, like possibly fireproofing of the area it's in, venting, exhaust piping rating, maybe sprinkler systems, etc. It's bad enough if this is a single family. If it's a NYC townhome or similar there are even more serious implications.
As I said before, if it were me, I'd have gone with a tri-fuel PORTABLE that is 5KW or so, together with a panel lockout kit and inlet. Much lighter weight than a 15KW elephant and plenty enough to run a furnace, a few fridges, freezers, lights, sump pump, etc. Just bring it out when you need it. You can hook it up when needed to a gas quick connect like you;d use for an outdoor nat gas grill. At 5KW, it would also not have the ridiculous gas reqt of the 15KW beast, so you could more likely be able to run it off the existing gas supply.
The other alternative, if you want a permanent install, is to get one rated for such installation. If it has to go indoors, I don't know which ones are rated for that. The nat gas, whole house ones that I've seen from Generac for example, that are market for typical homes, costing $3000 or so, are for OUTSIDE installation only and they make that explicitly clear. I'm sure there are ones rated for indoor, but I'll bet they are in a whole different price range.
It sounds to me like a whole lot of things should have been investigated upfront, before buying the genset.
15 KW is absurdly oversize for a single-family dwelling, except perhaps for northern Alaska, unless the OP plans on serving his entire neighborhood. In that case, he should be worrying about the size of the conductors he will be running across lawns and streets.
62.5 A is absurdly oversize? Not if you have electric heat, or need air conditioning for a whole house in the south. Ny neighbors have an 18 KW propane generator, but they are too cheap to have the tank filled.
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I suspect your gas lines are OLD, from the gas light/town gas era. Illuminating gas was made from coal and the line pressure came from the gas storage tank tops that floated on water in the tank walls. All the NG installations around here have regulators either incorporated with the gas meters or immediately before them, the disc- shaped housings are always visible on the outsides of the buildings. So all high-pressure distribution lines around here. There were no gas fields around NYC, it was all illuminating gas at one time. One reason our local gas rates have tripled in the last few years is that the east AND west coasts are sucking all of our NG away with new pipelines. And domestic inside lines are always low pressure, like
10" of water, regardless of regulation. One way to tell if you had illuminating gas is that immediately where the line entered the house, there was a tee with a capped 1' nipple hanging down for a tar trap. Have taken these off in older houses while renovating and found a whole lot of black goo, so were needed. My home town converted from town gas to natural gas in the '30s when they ran the first pipelines from OK to Chicago, my dad remembered having to redrill burners and pilot lights. Still had the gas storage tank next to the packing plant until I was in high school.Stan
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It might not be much but's there 24/7.
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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.
Now those gas storage tanks are next to all Taco Bells! ;-)
The location in the discussion thread is NYC. If he has electric heat there, which I don't believe is the case since he has nat gas, then electric heat is a problem of it's own that needs fixing. Who in their right mind would size an emergency generator to run electric heat for a house?
AC could be an issue, but it's not as vital in most cases as heat is. And instead of spending buckoo bucks on a big honking genset, it might be better to buy a window AC for $100 for an emergency, no? I would think most people can get by with a lot less during an extended outage, instead of trying to power life as usual.
house was built. Hell, I lived in one house that was built before water, gas, sewer or electric was availible. It still had four chimneys for coal stoves, and was built prior to 1868.
A well insulated, farily airtight house is better served by electric heat than gas, unless you feed outside air to the furnace.
How about people who are ill? I knew people up north with cancer who need the house to be kept at 60 degrees all of the time.
n the house was built. =A0Hell, I lived in one house that was built before = water, gas, sewer or electric was availible. =A0It still had four chimneys = for coal stoves, and was built prior to 1868.
WTF? Where do you live? Nat gas has been a far better deal than electric heat for most of the USA that requires heating for decades. Unless by electric you really mean a heat pump. Even with older furnaces that were not fed outside air. Right now nat gas is a great deal. Here in NJ, I don't know of a single person that uses electric heat. Gas or oil are 99% of the market. Electric is not even close in cost, nor has it ever been. Electric heat is generally used as supplementary heat for a heat pump system or where very little heat is needed. Certainly not NYC. It could also make sense in some pathological case, where say electric rates are exceptionally low, nat gas or propane are high.
Now I'm suspecting a troll. What person that is ill needs the house at 60F all the time? Assuming it's winter and you live up north, you can keep it at any temp you could normally achieve with a 5KW generator and a furnace that runs on gas or oil. If it's summer and you need 60F, well something is very wrong.
Excellent point indeed.
Gunner
The methodology of the left has always been:
Heh, and in fact, I'll be throwing my asshole neighbor a line.... LOL
Or, if you have a matchine shop.... :) You know what they say, calc your load, and then double it. And factor in that proly it's not a good idea to run a genset at max capacity, that the mfr is stretching things a bit to begin with, etc etc.
It's funny how all this works: On the one hand, I could get by with 3,000 W -- not running le shop, of course. Then, the mind plays with itself, and you wind up considering 30,000 W.... So I compromised w/ 15 kW...... :) :)
Also, innerestingly, the capacity is also dependent on how long the outtage will last. If it's only a day or so, 2-3 kW would be fine. If power is out 2-3 wks, and the laundry is piling up or you been sweating buckets at 100 F for a week, the extra capacity can really help. Oh, and the shop.... :)
Actually, for a week-long outtage, I would actually have to SHED load between the house and the shop. Even in the house istself, you proly wouldn't want to run a dryer and 5-ton CAC at the same time. That's over half capacity of 15kW right there. Factor in all the other stuff, and there's actually not tremendous leeway.
15 kW is, like, ONE 20 hp machine -- theoretically. You proly couldn't even START one 20 hp motor with a 15 kW genset, but you get the idea. Factor in compressors, etc, and actually 15 kW is perty perty tight. Sheeit, 1 kW is consumed by lighting alone!!But, with proper load-shedding, in a prolonged outtage, I'll be able to at least half-function, as opposed to being utterly paralyzed. Combine all this with the notion that you may NEVER use the goddamm genset, and you can go out of your g-d mind.... LOL
What does Vic Smith say?? Just move to a hotel?? Really, I toyed with that strat, as well. LOL Proly you could get some reimbursement from the utility, no??
Is there a similar generator to the one you purchased that is more than 15,000 watts? =================================================
Not that I could find, and not on that site. BUT, since these guys mix'n'match motors/generators all the time, I'm sure they could put one together for a specific order. Don't know how economical it would be, tho.
But when you get to 20,000 W, that's entering water-cooled, 4 cylinder, low rpm territory -- nice to have. You'll see some of those on that site, iirc.
200A is the standard electrical service around here. I've seen homes with electric start power plants that will provide 400A 208 three phase. They also had diesel powered water pumps for each of the 14" water wells for their nursery that they would fire up during power outages. I'm glad that I never had to pay their electric bills!
Which has little to do with what one needs for an emergency generator. It's not the service that counts. It's what you chose to have powered during a power loss. I have 200A. I did fine with a 6KW. A friend has 300A. He got by fine with a 4500KW generator during Sandy. Enough to run two furnaces,
3 refrigerator/freezers, and lights. But then I guess some people need to run all that, plus the jacuzzi, all the ovens, AC, etc, all at the same time. Hell, why not run the furnace and AC at the same time too.Sure you have.
A home with a 400A service, nursery and multiple 14" wells with diesel pumps? Around here we call that a business or a farm, not a residence.
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What a maroon.
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