Insulation on steam main piping

dopey27177

I resurrected this discussion.
See the enclosure on insulation on fuel savings by covering the steam mains.

Jake

ChrisJ

dopey27177 said:

I resurrected this discussion.
See the enclosure on insulation on fuel savings by covering the steam mains.

Jake

Multiple floors with 4" and 5" piping and 770 linear feet of pipe.....
That seems reasonable to compare to a typical single pipe residential system.

If the dissipated heat is in the conditioned space and the conditioned space does not over heat, is it "lost" ?

The Steam Whisperer

Those pipe sizes are just plain ridiculous. 4 inch two pipe steam risers can feed 3,800 sq ft of radiation. Also, a typical riser will feed at most 2 radiators per floor. All of those risers would each be feeding 10- 125 EDR radiators in each room. Most 1 to 2 bedroom living units from the 20's and 30s have only 150 to 180 EDR per unit. Each radiator would be heating a room around 1000 sq ft using typical radiator sizing of that period... about 60% oversized. Garbage in/garbage out. Also the pipes are not full of steam all the time, so there is another error in the numbers. On a typical system, on a typical winter day run time is about 20 minutes per hour.

Garbage in/garbage out.

dopey27177

To the steam whisperer.

Try to learn how to read. See the last part of the writings where the hours of operation are spelled out.
Try to understand that this building is a bit larger than anything you can whisper about.
Look carefully you will see only the steam supply system, no returns.

This is an exercise in heat loss. Maybe you need to run the figures with simple math.


Using your figure of 20 minutes per hour which does not cover wheather in the in the 20s and below you have 1040 hours of operation. my numbers indicate 1400 of operation.

Thank to god you never worked in my home.

Jake

ChrisJ

dopey27177 said:

To the steam whisperer. Try to learn how to read. See the last part of the writings where the hours of operation are spelled out. Try to understand that this building is a bit larger than anything you can whisper about. Look carefully you will see only the steam supply system, no returns. This is an exercise in heat loss. Maybe you need to run the figures with simple math. Using your figure of 20 minutes per hour which does not cover wheather in the in the 20s and below you have 1040 hours of operation. my numbers indicate 1400 of operation. Thank to god you never worked in my home. Jake

@The Steam Whisperer is one of very few I'd allow to work in my home.

The Steam Whisperer

I missed the hours of operation number and I certainly apologize for that, but I don't believe the piping system size is anywhere near reality. A 100 foot long main would probably be in a building at most 140 ft long and assuming 120 EDR per radiator (or around 1000sq ft per radiator) that would make the building about 57 ft wide, or about 8000 sq ft per floor. We typically see this size piping in buildings up near 14 stories on two pipe steam, not 5. If this was one pipe steam upfeed I could see these sizes, but I have found here in Chicago, that once you go over 3 stories, and even in large buildings ( maybe 60 units) at 3 stories, they go down feed for one pipe steam, running smaller pipe sizes. 2 pipe steam we've seen upfeed in 7 story buildings, but they go down feed typically in taller buildings.

I am all for insulating piping due to the potential energy savings, but using oversized piping system example is not going to provide a realistic result.

Also, I have not yet seen a detailed study of what the heat loss is from piping in an enclosed chase in an outside wall. I would suspect that the air temperature in the chase rapidly heats up, so that portion of the heat loss would reduce quickly once the steam in on ( however if the chase is open to the attic and lower levels, I would expect the heat loss to be highly variable). Now the radiant transfer to nearly 3 sides of brick that may already be warmed by previous heating cycles is probably variable too. The 4th side I would not consider loss since the heat is transferred into the interior space, so long as it is not overheating the space. Also, some of the hot air is probably transferring heat into the floor and ceiling cavities, depending on construction. For masonry, heat typically moves about 4 inches per day through the material, at least when looking at solar design ( those that live in brick houses can attest to the fact that it usually takes 2 to 3 days of extremely hot weather to begin needing heavy cooling in a brick home). The higher radiant temperatures of a steam pipe will probably move that transfer along, but again the heating is intermittant, so a portion of the heat absorbed by the brickwork will be radiated back into the building during the off cycle period.
Heat loss from the horizontal mains I believe is also harder to calculate than it first appears. An uninsulated steam main will increase the radiant temp. and air temp of the space it is in, reducing heat loss from the pipe. In addition, the hot air cloud at the ceiling and the direct radiant transfer of heat from the pipe to the ceiling, will tend to provide usable heat to the living space above, so if the space is not overheating this is also not a loss. We've seen plenty of cases where there are complaints of inadequate heating of the 1st floor unit when the steam pipes are insulated below. Of course, a warmer basement will increase the overall building heat load.

All this said, at least a portion of the heat lost from piping is not waste but provides usable heating for the building.

SteamingatMohawk

To me the most important goal is to put the heat where you want it, by insulating places where you don't want it to go. I think we all can agree on this.

Another goal is to determine the cost/benefit limit on how much insulation to install, unless the insulation is free. Just because "more is better", it doesn't necessarily justify the cost (labor and materials).

Finally, in any building, spaces with different "environments" will react differently...north vs south orientation, prevailing winds, heated vs unheated adjacent spaces, effects of tree shading and on and on, so each may need to be handled a bit differently.

Have a great day...I'm at the beach for two weeks. Ocean is in the mid 80s today. Where I grew up in NJ it didn't get to the mid 70s until mid August...

pecmsg

SteamingatMohawk said:

Have a great day...I'm at the beach for two weeks. Ocean is in the mid 80s today. Where I grew up in NJ it didn't get to the mid 70s until mid August...

A nice app I show guests to the beach house when they ask "Are there any sharks in the bay"?
https://www.ocearch.org/tracker/

SteamingatMohawk

Do you have any pics of them "Sitting on the Dock of the Bay?"

BobC

I remember swimming with what we called sand sharks when I was a kid. They were only 2-3 feet long and never bothered anybody unless you tried to take a fish away from them.