electric steam boiler for residential

teebone1500

I am adding a large solar panel system and converting one of my boilers over to electric. Does anyone know of a residential electric steam boiler that i can convert. the current oil fired steam boiler heats about 6,000 square feet

Steamhead

What make and model is your present boiler? How much radiation does the steam system have?

Jamie Hall

I hope you have a really big electrical service entrance. A wild a$$ guess suggests you'll need upwards of 300 amperes at 240 volts to keep warm on a cold morning...

teebone1500

we are putting a 24.8 KW hours solar system. I am not sure about my current boiler I can find that out. do residential electric steam boilers exist

Steamhead

Depends on how small you need to go. That's why we need to know what's there now.

GBart

Current boiler size means nothing for new equipment size, all it means if it worked on cold days that it is probably over sized.

What you need my friend is a heating engineer, not comments or ideas from a website.

you need a complete load calculation on the building, the piping inspected and radiators figured out or may end up quite sorry

teebone1500

I live in a 9,000+ square foot home that has a 2011 Oil fired steam boiler and a 2014 oil fired hot water boiler. The steam lines got re wrapped and upgraded in 2014. I heat the hose to 57 degrees in the winter b/c that is all we can afford to do. I paid over 6,000 for oil and propane last winter alone (I have 2 propane fireplaces) I am getting solar power in hopes to not use my oil fired boilers. Since the steam boiler heats 6,000 square feet I was hopping to convert that boiler to electric first. Their are 11 rooms with one pipe steam radiators. I know I could install other heat systems but I want to know If a residential house electric steam boiler exists ? if so can I have one installed to bypass the oil boiler to heat my house. I plan on leaving the oil boiler installed as a backup in case I run out of my electric from my solar panels

GBart

If you have a 9000 sq ft home, ugh, .......see where I'm going?

Electric steam boilers are not an answer, they are junk, problematic and you think your fuel bill was HIGH??

multiply that X 5 for electric, if you own a 9000 sq ft home it's not going to cost what it does for a 2500 sq ft average American home to run it, it is going to cost at least 4X that

Brewbeer

A 25 kW system is huge for a house, probably 75+ panels.
I'm not sure this is a money saver for you, since the system will likely cost more than 60k to install a grid-tie system (no batteries for storage). I own an 8.5kW system on my house, and the electric company pays me about 8 cents for each excess kW hour the system generates that I don't consume at the time of generation, and charges me 20 cents for each kW I use when I use more than the system makes. Also, while on a sunny day in the summer I will make 45+kW hours per day, in the winter when you need the heat, my system makes about 1/3 of summer production. On a cloudy winter day, my system might make 2-3 kW hours per day, and when it snows it doesn't make any power at all. So keep in mind that when you need the heat most, the solar panels will be producing the least.

A battery bank of sufficient size to run an electric boiler is not a cost-effective solution to storing excess electricity generated by the panels. I'd seriously look at mini-splits and/or solar thermal.

Jamie Hall

Reality check time...

There are some problems here... the first question is, what is the power output of your solar array, in kilowatts, not kilowatt-hours -- that's the energy storage capacity of the batteries associated with the array. There is a critical difference here.

Note that right at this point I'm not concerned about whether a residential electric boiler with adequate capacity exists...

The first question is absolutely critical: you have to know both the power output of your array and the energy storage capacity of your batteries to find out if you even have a hope of heating the house.

So, the reality check here. The solar constant (the power incoming from the sun is, very roughly, 1 kilowatt per square meter or, again rather roughly, 100 watts per square foot. Now most photovoltaic systems can manage to convert at most 20 percent of that to electricity, so we are looking at a maximum output of 20 watts per square foot -- of a surface in full sun, oriented directly towards the sun. Now 1 kilowatt is, roughly, 3500 BTUh.

Now a rather well insulated 6,000 square foot house might have a heating load of around 120,000 BTUh. (A less well insulated house could be twice that) That's 35 kilowatts.

Now it is conceivable that an array could be installed on your roof which will produce 35 kilowatts; that would require 3500 square feet of array -- if you actually have 3500 square feet of photovoltaic panels, and they are mounted to track the sun so they are always facing the sun, they will produce just enough power to heat the house -- while the sun is shining.

Are those conditions realistic? Ah... no. First, again unless you install a tracking array, the panels aren't oriented towards the sun except for one brief moment on one (or two) particular day(s). Second, and perhaps most important, the sun doesn't always shine.. which is where the storage comes in: you need to have enough storage capacity to keep the power going when the sun goes down or a cloud goes by.

This is where things get more interesting, as now what is needed depends very much on where you are. In the northeastern US and Canada, a rough but useful rule of thumb is that, on average, you can count on 3 hours of sunshine per day, but with as much as 3 days in a row with no sun at all. In parts of the plains states and provinces, you get more sun, of course. To meet the heating needs mentioned above, you would need enough storage capacity to cope with that, and let's suppose we are real optimists, but live in the northeast, and figure that the sun is going to shine on our array for an hour every single day. We need then to store enough energy for the remaining 23 hours: 35 KW times 23 hours, or about 800 kilowatt-hours. Furthermore, we need enough power coming from our solar array to recharge that storage in 1 hour... 800 kilowatts from our array.

Which is some distance from what you are proposing.

I'm sorry to rain on your parade, but physics isn't amenable to either hope or hype.

Can solar heated houses be done? Indeed they can. I've designed several in cooperation with my father in law, and lived in one myself, all in the northeast. They were all semi-passive direct solar space heating with storage. A very well done active solar hot water system can also come close. But can photovoltaics mounted on the house do the job? Flatly, no. No hope. Not even close. Can a photovoltaic array system be built which will do the job? Yes -- as they say in engineering circles, give me enough money and I can do pretty much anything.

I hope this helps you...

Steamhead

What @Jamie Hall and @Brewbeer said.

With that in mind, the next logical step is to have a Steam Guy look at your system to see if there are any obvious problems that make it so expensive to run. Often just by getting the basics right, you can cut fuel consumption drastically. Check out my company's Find a Contractor ad- it describes one job where we cut their fuel consumption by a third.

Also, since this is an oil-fired boiler, have someone other than the oil company service it. This will be more than the typical (at least for this area) in-and-out-in-45-minutes deal. You have to open up the boiler, brush and vacuum it, close it back up, install the proper nozzle and filter and tune it with a smoke tester and digital combustion analyzer. This takes a lot more than 45 minutes but can result in noticeable fuel savings.

Where is this job located?

newagedawn

you could wire the existing boiler into your charge controller 28.4 killowatt hrs is alot, most houses use 6 to 8 a day,you might want an electrician to wire in a killowatt meter to find out the daily consumption of the boiler in winter first, then factor that into your system, wow that gave me an idea to do that very thing,lol

Jamie Hall

Oh dear -- read my commentary above, @newagedawn -- 28.4 kilowatt-hours perhaps seems like lot -- but not when you start trying to create heat with it (one of those little 15 amp space heaters -- 4000 BTUh -- will use that in a day).

GBart

Aye a 9000 sq ft is going to cost to run, steam is efficient possibily supplement with heat pumps, house that size could use a Daiken VRV system, and your pv panels could easily run that.

Check it out.

https://daikincomfort.com/go/vrvlife/

A house that size could also use a small commercial Daiken system, you're talking 4 times the average American home = 4 x the cost to run it, use your heat pumps when it's above 25 or so and then use the rest.

Jamie Hall

How much power (watts) does the Daiken draw, @GBart ? Remember the OP gave use KW-hours of storage, not panel output....

JUGHNE

I think he meant the out put would be 24.8 KW (max) under ideal conditions. If those conditions existed for one hour he would have gained 24.8 KWH to send somewhere.

Jamie Hall

Well, he possibly could put up that much panel -- somewhere around 2500 square feet of it (minimum) ... somewhere...

GBart

Jamie Hall said:

How much power (watts) does the Daiken draw, @GBart ? Remember the OP gave use KW-hours of storage, not panel output....

A lot less than a 300,000 btu electric steam boiler

GBart

JUGHNE said:

I think he meant the out put would be 24.8 KW (max) under ideal conditions. If those conditions existed for one hour he would have gained 24.8 KWH to send somewhere.

You can't, net metering is a law put forth by the electric companies to stop solar power in it's tracks and to keep from having to pay people for adding to the grid, most you can usually get is a credit on your bill and in some states it's illegal or (not code) to over build a solar pv system because it would, in the end affect stock holders and that's all America cares about, profit and stock holders.

Jamie Hall

GBart said:

JUGHNE said:

I think he meant the out put would be 24.8 KW (max) under ideal conditions. If those conditions existed for one hour he would have gained 24.8 KWH to send somewhere.

You can't, net metering is a law put forth by the electric companies to stop solar power in it's tracks and to keep from having to pay people for adding to the grid, most you can usually get is a credit on your bill and in some states it's illegal or (not code) to over build a solar pv system because it would, in the end affect stock holders and that's all America cares about, profit and stock holders.

Not quite true. At least not here. Although the alternative is considerably more complex: you can give a solar power company a land lease on which they can erect a commercial array. The red tape involved is, to put it mildly, impressive...

JUGHNE

By sending that 24.8 KW I was referring to it supplying inverters for household use, battery storage??, or directly to resistance heaters if such exist for whatever DC voltage is supplied.....and sell back to utility if possible...…..however...….

IIWM, I would invest in the mini split heat pump system to heat the structure as much as possible then switch the steam heat on as needed. You get the benefit of AC also.
24,800 watts of electricity will give you only 84,642 BTU's.
If you look at the nameplate on your boiler it will give you some perspective of how much heat you are now producing.

The money you might sink into a huge solar collection system, I believe, would be better spent on the heat pumps......even as much as I do not enjoy forced air.

You could go for the solar in the future.

Also if you have a gas LP log in the original fireplaces with out sealed combustion and fans to deliver hot air, you may be sending a lot of heated air up the chimney.
Most old fireplaces are heat losers without modern features installed. IMO

the_donut

I would also look at building envelop. Money spent in air leakage sealing and insulation will payoff in any heating system you choose.

Leonard

Old fireplaces were +10 to -10% efficient. They draw heated air out of house, I freeze when I'm at my cousin's and they light a fire, especially in other rooms. Finally this Thanksgiving they didn't light a fire and I was warm (oil heat).

Very costly to store power in batteries, and those $$$$ bats will have to be replaced periodically.

Other issue is you can run most any size oil furnace with a small generator if you have an ice storm power outage. Go with heat pumps and you may need a large gen to start and run them. If you have air instead of geothermal based heat pumps, then their deice electric heat strips will likely make generator power needed very high. Gens power is much more expensive than utility power (~ 2 - 4X, run your numbers), and thats just considering fuel costs, not equipment costs.

Paul Pollets

A good engineer with solar experience should be able to make adequate energy comparisons. I wouldn't want to use a rooftop array to power a large electric steam boiler. First, the load would probably be much larger than the array could produce; second-the solar angle decreases in the winter so panel output would be reduced when you need the amps. Harvesting a thermal solar system for DHW would be a good way to use solar, but electric steam in a large home?? I'd make sure the burner and boiler be thoroughly checked out for optimum efficiency, as was said above.
Is the home well insulated? Are there quality windows?

GBart

Jamie Hall said:

GBart said:

JUGHNE said:

I think he meant the out put would be 24.8 KW (max) under ideal conditions. If those conditions existed for one hour he would have gained 24.8 KWH to send somewhere.

You can't, net metering is a law put forth by the electric companies to stop solar power in it's tracks and to keep from having to pay people for adding to the grid, most you can usually get is a credit on your bill and in some states it's illegal or (not code) to over build a solar pv system because it would, in the end affect stock holders and that's all America cares about, profit and stock holders.

Not quite true. At least not here. Although the alternative is considerably more complex: you can give a solar power company a land lease on which they can erect a commercial array. The red tape involved is, to put it mildly, impressive...

For homeowners it's verboten

Henry

A steam boiler sizing is NOT done by the volume of the building! One has to evaluate how many square feet of radiation is installed. Small commercial electric steam boilers are available. I am sure that your electrical rate is higher than the propane or oil equivalent. You need someone that has very good knowledge of a 1 pipe system.