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Steam vs. Tubular Radiant Heat

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wahoover

Mechanical
Feb 6, 2008
2
I am working on a project in Central PA where my client has an existing steam system that is very inefficient and would like to change to a tubular radiant heating system.

This facility is a 110 year old manufacturing plant that is approximately 92,000 sqft. The building is a typical turn of the century (last century) manufacturing style construction with 30' high bay in the center and 16' roof deck on either side with lots of glass. The building also has no insulation except possibly 1" on the roof that was installed when the building was re-roofed several years ago.

My client is looking for cost savings by changing to teh radiant heating system. My gut tells me he will experience a 3-5 year pay backa and reduce heating costs between 40 & 50% however I do not have any concrete documentation that I can refer to for this feeling.

Has anyone done a similar conversion or can anyone direct me to documentation on cost saving that may be seen?

 
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My advice would be to do a proper whole building cost analysis- it may be more bang for the buck to police up the envelope and save energy directly that way before relying on different heat emitters that still try to offset the same building heat losses anyway. All the radiant emitters will allow is to maintain comfort with lower air temps, but given the poor envelope, the place obviously suffers from poor mean radiant temps inside the building anyway.
 
There's a good chance that the steam system can be made MUCH better for very little money spent. It could be something as simple as a condensate pump that's packed it in, and now the boiler is making steam with 45*F make-up water instead of 180*F condensate.
 
My complaint about the radiant tube heaters is that they list their 'efficiency' without actually describing their combustion efficiency, which is usually quite low. We also receive a number of comfort complaints (hot on the burner side, cold at the end of the tube).

We do use radiant tube heaters for plant applications, because of the low capital cost, but I've never considered them for energy reductions (due to the low combustion efficiency of the heater ~70-75%!)

I've heard of some better units (up to 80% efficient?), but I agree with GMcD and TBP, if you're looking to do an energy retrofit their are some much better options to consider.

After envelope upgrade, my next thought would be boiler upgrade (actually my first thought is boiler upgrade because I don't get paid for envelope upgrades, but I agree with GMcD in principle).

Possibly converting to a hot water sytem, possibly trying for a modulating/condensing boiler.
 
Thanks to all that have responded. I will look into each suggestion. Looking at the envelope is a great idea however the client was nto interested in this option when I originally suggested it during one of our earlier meetings. I like the boiler idea and may look into this further.

Thanks again.
 
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