sizing calculatons for old boiler

Brad White_203

You have to love Philadelphia new construction! :)

START with a qualified heat loss calculation, taking into account any and all improvements made, insulation, glass, roof insulation, whatever it may be, whatever it happens to be now even if not improved. "It is what it is", but define the reality.

There are no shortcuts here.

Now, is the building heated by steam? (you said "heat and hot water, but heat could be steam, showers etc. hot water of course.)

If heating is by steam, retain what I said above, but in the back of your mind. Steam boilers are sized to suit their connected radiation. Got that?

Now, you can hope that the heat loss and the size of the radiators have something to do with one-another. Maybe, maybe not. But unless you remove and replace radiator sections to suit any improved heat loss reductions, size that boiler on connected radiation.

OK, if heated with hot water, great. Size the boiler to the actual heat loss. If the radiators are oversized, you get to run on lower water temperatures. Very cool.

If you went ahead and matched the new boiler based on anything but a detailed heat loss (or connected radiation if steam), you are doing a dis-service to your client.

There is a LOT we could talk about, to insulate an old brick building (or not to), how to air seal it, reducing steam radiators and thus the boiler to a new lower heat loss, etc.

May this get you started.

Brad

Chris_106

old heater sizing calculations

I’m doing some energy consulting on a old building in center city Philadelphia. The building was built in the 1870’s, 3 stories + basement. The total area is about 9,000 square feet. It was originally a single family residence for a prominent architect, but has since been divided up into office space with several zones for heating and cooling. It is about to undergo it’s fourth or fifth retro fit. The owner wants to maintain office space and maximize the energy efficiency of the building.

The boiler is an old HB Smith, coal converted to oil. It produces the heat and hot water. The dimensions are something like 5 ft high, 5 ft long, and 10 ft long. What sort of old-timey calculations do you think were used to originally size this thing?