Single pipe steam efficiency

Bill_6

During the past winter I had some days of 0 °F. I measured my boiler run time at about 40 minutes every hour. My system works very well it's more cozy the colder it gets. ALL the exposed and near boiler pipes are insulated with 1.5" compressed fiberglass.

My oil nozzel = 1.8 Gal/Hr but I upped the PSI from 100 to 130. So I figure maybe it's 1.9 Gal/Hr and if so I'm using 1.267 Gals each hour. With oil at 140000 BTU's/Gal that = 177,333 BTU's/Hr. My boiler is a 1977 Burham V5 230MBH maybe 75% efficient so 177,333 * .75 = 133,000 BTU's/Hr. If my delivery system is 70% efficient then the actual BTU's seen in the house = 133,000 * .7 = 93,100 BTU's/Hr.

OK you experts how close am I ? Tell me where I'm wrong.

It's the Arabs fault but I'm having to go away from my beloved steam heat. The oil is just getting too high. I'm looking at geothermal heat pumps as a replacement, and so need really accurate BTU calculations. If my numbers are panning out the payback is close to $1500/yr current oil & electric prices.

Steamhead

Need to know

how much radiation you have. Also, how well is the house insulated? Have you done a heat-loss calc?

Bill_6

640 Cu Ft steam (boiler rated > 700 Cu Ft)

6" insulated walls, 10" attic, (0" floors (1/3 = boiler room rest = enclosed crawl)) 2 story house

Slant Fin heat loss calc = 65000 BTU's total ( I think this is low)

I've done another H/L including AC = 75000 Heat / 41000 cool
(with inflitration = automatic enter = 81000 Heat; the above is manual enter 1/2 of auto)

I've got the upper level turned back with hoffman valves closed. Still's around 55 - 60 °F

Steamhead

Well, 640 square feet of radiation

equals 153600 BTU per hour. That's over twice the heat loss.

Regarding the heat loss, if you insulated the floor over the crawlspace you'd get it down further. And a blower-door test would locate air infiltration leaks for you. This should all be done before you decide what to do with the heat.

Since you have so much more radiation than needed, how about finding some smaller rads?

BTW, are you the same Bill Bass located in Bristol, at the Virginia/Tennessee border?