Huge Steam Boiler

Bob_19

> A client came to my firm recently with the <BR>
> following project: 500,000 s.f. early 20th <BR>
> centruy paper mill turned distribution warehouse. <BR>
> (8000 degree days) It is currently being heated <BR>
> by a steam boiler which was reportedly also used <BR>
> to provide heat for the paper processing. The <BR>
> utility company has told him that by installing <BR>
> small gas fired unit heaters he could pay for the <BR>
> work in a year with fuel savings due to increased <BR>
> efficiency. The building is wholly uninsulated. <BR>
> The question is: Will running a large steam <BR>
> boiler at one half or one quarter of it's <BR>
> capacity reduce the efficiency to this degree? <BR>
<BR>

Steven McCray

huge steam boiler

A client came to my firm recently with the following project: 500,000 s.f. early 20th centruy paper mill turned distribution warehouse. (8000 degree days) It is currently being heated by a steam boiler which was reportedly also used to provide heat for the paper processing. The utility company has told him that by installing small gas fired unit heaters he could pay for the work in a year with fuel savings due to increased efficiency. The building is wholly uninsulated. The question is: Will running a large steam boiler at one half or one quarter of it's capacity reduce the efficiency to this degree?

bigugh_4

You are close

to understanding the problem, and it is a problem.
Here is some insight. Unit heaters are not that comfortable. and not efficient. IF, you have the cieling height, & nat gas avaliability, look to infrared cieling mounted heating. These tube systems are super at heating large areas. they fit well in warehouses. You get radiant heat, (warms things,not air). cieling out of the way placement. usually easy installation. Direct venting (thru the wall). This would have been the way it was heated had the equipment and gas existed when it was built.

Steamhead

First thing to do

is insulate, weather-strip, install better windows etc. There's no point in replacing the heat system until the building is in better shape. Then whatever goes in can be smaller, and use even less fuel.

Why not replace the old boiler with one sized just for the heating load/radiation? This would save the trouble and expense of running gas lines all thru the building.

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Bob_19

Is The Boiler

setup for modulation at this time?
I would imagine that this is a hi pressure boiler.

I would contact the factory and inquire about turndown capacity of this boiler. Most larger boiler(but not all) will have a turndown designed into the generation capacity. This alone can decrease short cycling issues.

Efficiency is another question, if the loads change often modulation would be the best route, if it stays somewhat continuous then turndown would be the best route.