High efficency Steam

[ransley]

Does any company make small high efficency 90%+ condensing steam boilers for residential, or are they all 85% or so efficent. I know water heat and large steam can be 90%+.

[mark]

The only steam boiler I know off to meet your spec is a Fulton Electrode boiler.Runs from electricity so no heat going up a flue.

[meow2222]

I gues you're looking at direct contact boilers.

NT

[ransley]

Im in the US I know UK law is condensing heat units are the only ones allowed where this group is, so what does everyone do on small steam, at what BTU size are condensing steam made, I have Ng.

[mark]

Steam boilers were/are rated in pounds per hour and at one time was the pounds weight of water they would evporate from cold.That is now classed as from and at which is commonly 85 degrees C to 100 degrees C. Are you sure it`s a steam boiler you want and not a condensing hot water boiler? Fulton boilers were owned by Twin Industries of New York.

[ransley]

In the US we rate by BTU, in a fairly large house we have a 300,000 btu unit. In a 12 unit,1 bedroom apartment building I have an old,

1,100,000 BTU Kiwanee, Scotch Marine, 2 pass, low pressure steam unit, both are Natural gas, both are probably 55-60% overall efficency because they hold alot of water.

Looking to upgrade but modern smaller units here are only 82-84% total efficency, a condensing steam can go to 92-96+ % efficent. So how do you guys with condensing unit mandates put in small condensing steam of 92% + efficency, when I cant find them in the US.

Here our dumb ass gov has no energy mandate on boilers like you guys do. Here nobody even believes in tankless Ng water heaters.

Here builders in the North where it goes to -30f still put in 82% furnaces, and spend the savings on a hot tub, or big Tv.

[Andrew Gabriel]

Steam boilers are not used in UK residential (and weren't even before energy efficiency rules on boilers were introduced), except in specialist industrial sectors.

If by "condensing" you are referring to condensing out water from flue gasses, that would seem to be at odds with a steam boiler. If by "condensing" you are referring to recycling the steem, then you lost me.

[Onetap]

Steam boilers are not used for domestic heating in the UK, our Pressure System Regulations do not allow it.

Ask here, everything you could want to know about steam heating.

any UK residents are interested, the domestic steam heating boilers used in the US do not operate at high pressures, but only evaporate several ounces of water in the heating cycle.

[meow2222]

there are various exceptions, and non-condensors are still fitted

No-one uses steam heating domestically here, not since WW2. Also as said a condensing boiler must inevitably heat water to significantly below 100C, so there appears to be a conflict in what you want there.

Best efficiency boilers here are direct contact industrial units. Flue gases and circulating water are in direct contact for 95%+ efficiency. However I dont have enough experience of that sort of thing to suggest any makes, its just google fodder.

I dont know whether you could take a standard boiler and fit an external custom heat exchanger to provide warm air from the remaining exhaust heat, or perhaps warm water for UFH / in-wall heating / HW preheating or any other lower temp use. No idea on the US legalities of that.

NT