Hypothetical question: New boiler and smaller radiators

Steve Garson_2

This question is simply to satisfy my curiosity...

Steam systems were designed, in most cases, before insulation and tight houses. My steam system runs around 15 minutes an hour on a design day.

If money was no object, and I needed a new boiler, would the system be more efficient if the radiators were replaced with smaller ones that resulted in constant operation on a design day? I assume that radiator size would be based on heat loss.

Thoughts?

Steve

Jamie Hall

The best answer to your hypothetical question is... most likely. Particularly if you resized the radiation to take into account any tightening of the building envelope. Assuming you did not, however -- building envelope unchanged -- you would probably save a small amount of money on fuel. However, your return on investment almost certainly would be very very negative.

GW

Hypothetically speaking, things get funky when you account for set backs thernostats. If John Doe drops 10degeees in Jan, you want your bigger system. If Jane Doe across the street has the same set up but drops back 3 degeess, you want the smaller set up and save some fuel.

gerry gill

In theory, if you know for a fact that half the radiator heating, now heats a room on design day, you could in fact put in a boiler that delivers enough heat to heat half the radiator. If in your hypothetical question you made the rads smaller, you obviously would use a smaller boiler. If you hypothetically left the same radiators and the steam was only partially filling the rads and still heated just fine, your good to go, as the steam doesn't know how much radiator is still there unused. I think Frank Gifford does things along those lines.

Steve Garson_2

The radiators all heat up 100%. Good venting.

jumper

If you change radiators why not switch to panels to improve radiation/convection ratio?

Eastman

@gerry gill

I think you mean Henry Gifford.

energysavingscience.com

There's a couple articles on his site that advocate using orifices and TRVs.

gerry gill

yup, thats him, my bad.

Eastman

@Steve Garson

Steve Garson said:

The radiators all heat up 100%. Good venting.

If you downsized the rads, but kept the boiler the same, I believe the system would be less efficient. --The boiler would cycle on pressure more frequently.