EDR on pipe-based radiator

jsavage

I have this radiator (one of two 2-pipe radiators in my 1-pipe system) and am trying to determine the EDR. Diameter is 1 1/4 and each section is 24” wide. Using the EDR guide for direct pipe coils from The Lost Art pg 123, I could see two ways of calculating this. It’s either 24’ of single-row (EDR of 16.2) or 2’ of twelve-row (EDR of 8.38).

Any thoughts on which one is correct?

Jamie Hall

Just calculating the surface area of the pipes I get an EDR of about 9. Give or take.

jsavage

Awesome, thank you!

JUGHNE

It would be interesting to see how this is piped under the floor, seeing how it is a 1 pipe system.

jsavage

Gladly! It’s a neat system!

Take off from Main:


Branch, Supply to Radiator and "Home Run" return that goes all the way back to a wet return before joining any other returns (as almost all of the returns do):


Dry return going into radiator "room":


Dry returns become wet returns in radiator "room":


Radiator "room" from boiler side:


Wet return to boiler and near-boiler piping:

jsavage

Here are some floor plans to help orient you.

gerry gill

nice, thanks for sharing all that

JUGHNE

Thanks for photos.
How does the air get out of that pipe rad?

Steamhead

Vertical pipe from bottom of radiator (1/4"?) with a Vari-Vent on top.

jsavage

Yes, there’s a tap at the bottom. The vertical pipe is 1/8”.

JUGHNE

Now I see the air vent....old eyes here.

I was admiring your NBP but cant't see a Hartford Loop, is there one somewhere in there?

ChicagoCooperator

Hey, you've got a drying room! (and looks like you have a lovely house - Vaporvac's suggestion of a house tour suggestion sounds good)

jsavage

These pictures should show the Hartford loop. It’s there but I’m unsure if it’s high enough.

ChicagoCooperator, not sure what you mean by drying room. I’m happy to post some house pictures when I have a chance... it is quite a nice house and I’m very lucky to have the opportunity to live in it!

jsavage

... also happy to give a tour in person to anyone who’s in the area or driving through.

ChicagoCooperator

Line drying the washing (my mother has them in her building and loves them - better for the clothes).

BobC

I've been hanging the wash out to dry all my life, saves a lot of gas. In the winter there are lines down cellar that are slower to dry but still save gas.

Bob

jsavage

I’m not sure if you’re referring to the drying room as the room I labeled “radiator room”, but that room is inaccessible except through some small cast iron doors. It houses 4 banks of gold’s pin indirect radiators that provide hot air to the first floor.

Steamhead

jsavage said:

I’m not sure if you’re referring to the drying room as the room I labeled “radiator room”, but that room is inaccessible except through some small cast iron doors. It houses 4 banks of gold’s pin indirect radiators that provide hot air to the first floor.

Can you say "Heating Museum"?

jsavage

I could. I’ve given tours of it to every single person who’s visited our house!

mattmia2

So a very large fancoil but gravity...

John Ruhnke

@Jsavage
awesome pics!! I would love to visit your place sometime!! The header looks real nice the way its piped.

That Hartford Loop is a little too low like you said but I can see a low water cut off on the boiler behind it. When they invented the Hartford Loop they didn't as of yet invent the low water cutoff. So at least you have some protection. They both are meant to protect from a low water situation in the boiler.

jsavage

Here are some pictures of the HB Smith Gold’s pin radiators for reference. Most of the radiators in the house are HB Smith radiators.

I also attached an ad for the local HB Smith office that was published when the house was built.

Fred

Fantastic! Is that large duct in your 4th picture the supply (return) air? I assume the smaller ducts seem inside the radiator room feed first floor rooms by gravity, much like the old gravity hot air furnaces?

mattmia2

Are those radiators repurposed boiler sections?

jsavage

@mattmia2 No, they’re Gold’s pin indirect radiators. I attached the page from the HB smith catalog for reference.

jsavage

@Fred that is actually the 16” supply to the dining room. Next to it is the abandoned supply to the kitchen. There is another abandoned supply to the front entry way that was 16”. Then there’s a run in the wall up to a room on the second floor that’s 10” coming out of the radiator room, a 12 or 14” supply to one side of the living room and a 16” supply to the other side of the living room. The way the system works is that the intakes are below the radiators and the supplies are above. The smaller 10-12” intake has been removed, but the main intake is there, just sealed off.

I say intake rather than return because the air comes from the outside of the house via a massive 34” x 16” duct. I don’t have a picture of the inside duct on my phone, but here’s one of the outside of the house. I originally thought it was simply a large basement window!


Yes, it all works by gravity. The system pulls in cold air at the bottom of the room (the large intake ties in at the very bottom of the room), the radiators (about 5’ off the ground) heat the air, and it blows out of the vents. Because of how much heat the radiators put off, the speed of the air is close to what you’d see on the lower end of CFMs for a forced hot air system. The air itself is 110-120 degrees, which is really perfect and creates a real warmth in the room that is superior to anything I’ve experienced before. It also heats very quickly.

I want to try and put the whole system back in service. At some point, radiators were added in the front entryway and living room that should not need to be there based on my Manual J calculation. The big unanswered question is whether the outside air intake is worth the obvious efficiency loss. I could see it being really nice having positive pressure throughout the house in the winter though!

Fred

Nice! It just seemed to me to be more efficient if the "cooler" air was drawn back into the radiator room from inside the house, rather than outside air, much like the old gravity hot air furnaces that I am familiar with. Doesn't seem reasonable to heat zero degree outside air in and heat it to 100+ degrees when you can draw 60 degree inside air back into that room and heat it to 100+ degrees. It also seems to me that, unless you have an extremely leaky house, you can't keep up with the number of air exchanges required to constantly/frequently cycle cold air in.

John Ruhnke

I love reading about the history of these old steam systems. They really had some unique designs. These posts on your system are great!

mikeg2015

Bare pipe in that configuration, might outperform that base EDR calculation because of conventive air currents. However, it’s also painted silver which can reduce output slightly.

jsavage

@mikeg2015 plus the fittings throw off some heat. It really throw off a lot of warmth based on my observations.

jsavage

@Fred That’s probably the case. When I tested it, I just left the access doors open in the basement and that provided sufficient return air.

This is actually the way these systems were originally designed... in fact I wasn’t able to find any marketing materials that used an interior return with these radiators. The boiler may have originally been situated under the indirect radiators, so there’s a possibility that some of that intake was used for makeup air for combustion. I now have a fan in a can. I can see a damper from the outside, but haven’t been able to access the lever from inside. Once I find that I’ll probably experiment with just opening it slightly in the winter. Considering that there is no fan, I think there’s some possibility that the system will be self-regulating due to the pressure differential between the outside and the inside.

Unfortunately, I can’t test any of this until it’s cold outside!

jsavage

@John Ruhnke I totally agree. Let me know if you want to make a trip out our way, I’d be happy to treat you to lunch or dinner. My cell is (401) 935-6150.

John Ruhnke

@jsavage

If I ever travel to RI again I will look you up.

Thanks for the offer.

acwagner

@jsavage

I know I'm late to the party, but to answer your original question, I believe the 2' of twelve rating is the correct rating.

Basically, the inner tubes radiate some of their energy into tubes above and below versus directly into the room, which is less efficient than the same length of a single straight pipe that radiates unobstructed into the room. Even though they have the same surface areas, they transfer heat to the room at different rates. Hence the two different ratings in the book.

Here's a paper from back in the day that covers this phenomenon (starting at page 12), plus other things that de-rate radiators:

https://heatinghelp.com/heating-museum/no-540-heat-losses-from-direct-radiation/