Stratification in a church

Chuck_17

100 year old church with a high (50 footish) peaked roof.
It had steam radiators actually tucked into shallow alcoves in the side walls (not covered). They have been remove and now we will be installing hot water fintube.
Who thinks stratification will be a problem (worse than with the steam radiators)?

kcopp

Why was the steam removed???

Paul48

Steam was the perfect match for a church. I hope you have thought the potential problems through.

bob_46

If you use panel radiators with an average water temp. of 210ºF and ∆T of 10ºF you should be OK. You need a lot of radiant surface and high temperature.

BobC

Whoever ordered the steam removed may have to answer to God, they had better have a good reason and deep pockets.

Bob

Jamie Hall

You asked who thought stratification will be a problem. I do. It will be much worse than it was with the steam, as the fin tube depends on convection, not radiation, to provide heat. The steam provided direct radiation at floor level; there is almost no radiant gain from fin tube.

Therefore, you absolutely will have to have ceiling fans to provide any level of comfort at all, and to keep the cost of heating the space where the congregation actually is -- mostly near floor level -- at something reasonable (although even so it will be more than the steam was).

I have actually seen this exact scenario, and it's nothing short of tragic. Cost the church a major bundle. Why on earth was the steam removed? Someone gave very very poor advice.

I might add... that you could try panel radiators operating at 210, as @bob suggested above. That would be almost as good as the steam was (steam operates at 215) and would give you the radiation. Then you would only be out the cost of the conversion -- two or three times what it would have taken to bring the steam up to speed, perhaps, and with no gain in efficiency or lowering of operating cost. But I take it from your message that fin tube has already been decided on, so that's not an option...

But why? Why on earth was the steam removed?

Paul48

In a normal situation, you might be able to get away switching radiators with fin-tube. Churches, and their wildly different heating requirements, are anything but normal. They need to be over-radiated to warm the structure up quickly for masses, but can be kept much cooler for the majority of the time. They are best suited to multiple, staged boilers, properly controlled.

Gordy

Come on now. Not all churches are heated with steam. However they were not initially heated with steam by design either................

Jamie Hall

Gordy said:

Come on now. Not all churches are heated with steam. However they were not initially heated with steam by design either................

Quite true. The church I used to go to in Vermont was heated with one huge wood stove at the back of the chancel, with radiant gain from the stove pipe which went overhead to the front...

Gordy

Stratification will be the monkey on the back. Most deffinetly. I hope ceiling fans of an industrial variety are already in place.

Harvey Ramer

I did a bid on a similar project. Vaulted ceiling that required binoculars to see the peak. No insulation in the ceiling. Just hardwood with a slate roof. Steam was getting ripped out. I proposed radiant supplemented with panel rads. I lost to furnaces. They will pay.

Gordy

I'm wondering how many more alcoves need to be built for the extra fin tube over, and above the existing steam rads......

Gordy

Harvey Ramer said:

I did a bid on a similar project. Vaulted ceiling that required binoculars to see the peak. No insulation in the ceiling. Just hardwood with a slate roof. Steam was getting ripped out. I proposed radiant supplemented with panel rads. I lost to furnaces. They will pay.

Key words: radiant supplemented with panel rads

Jamie Hall

@chuck -- did we scare you? Didn't mean to...

MilanD

I was almost convinced at one time to go hot air furnaces when steam needed to be repaired... on a 20+ ft vaulted ceilings... amazing. To a hot air hvac hammer-head, every solution is (full of) hot air. Glad I'm stubborn by nature and don't listen 99% of the time (just ask my wife), so I had the steam repaired instead. Glad I did. Esp now that I know more than I knew then.

Just to point out hot water at 210F is 210btu. Steam is 1150btu. There it is as to how much more calories or btu is there to heat the space in comparison.

If this is salvage situation and steam is indeed ripped out and not just needing repair, I am really not sure what the best way to do this would be... some kind of radiation and convection combo... and that wood stove Jamie mentioned, with a long flue pipe.

Good luck...

Chuck_17

Thanks for the replies.
The radiators were removed (for the scrap $) before my involvement. The church realizes their blunder now (too late). The building has not had heat for two seasons now.

I will consider panel radiators. Any idea of cost vs. commercial fintube)? (relative cost - not looking for an estimate) (I can ask the supplier). Cost is a major factor.

Thinking aloud - Does the use of panel radiators reduce the amount the hot water temperature can be lowered vs. rise in outside air temp? (radiant heat transfer is not linear)

GW

Yes the panel rads emit heat with less heated water but that means nothing when you're trying to heat a large space. Unless you're maybe referring to spring and fall fuel savings.

I'd be very curious to see this cone through with baseboard. You're gonna need some commercial connectors or something that can really move lots of BTU

Cost better be a factor or you'll be sorry you ever got involved. I admire you wanting to help but you gotta make it work or it's your problem

Gary

Jamie Hall

As has been mentioned... a church is a challenge to heat. Part of the reason for that is that for most churches it is desirable to turn the heat down for much of the week, but be able to provide enough heat to keep the congregation at least vaguely comfortable when they are present.

One of the approaches to doing that is to recognize that radiant heat heats the objects -- including the parishioners -- rather than the air. Therefore... I would be much inclined to go with both panel radiators and fin tube, if you can. Panel radiators could be placed where the late and lamented steam radiators were, in the alcoves, and fin tube -- or more likely two lines of fin tube -- along the rest of the perimeter.

That, in combination with overhead fans, will give you a fighting chance of heating the space fairly quickly to the point where people are adequately comfortable.

On water temperature, though -- again, you are looking at radiant gain at least in part, and to do that you are going to need the system to run hot. I'd want it to run the panel radiators at 200 plus -- indeed, as close as your controls will let it be to boiling (215) as possible without actually boiling -- at the input, and design for about the usual 20 degree drop. All the panel radiators would be in parallel. If you wanted to be able to handle less flow, you could run the output from the panel radiators (at, say 180) through the fin tube banks before returning to the boiler.

On cost. I hate to tell you this -- and being involved with church finances myself, I'm really sensitive to it! -- but any variation on hot water is going to cost you more to install and to run than the steam would have cost to repair and to run. The running costs will not be that much more than the steam, properly upgraded maintained, would have been. The installation cost is going to be eye-watering, no matter what option you choose.

Your question on temperature suggests that someone was hoping to reduce water temperatures in the shoulder seasons, perhaps with outdoor reset, with a modulating/condensing boiler, such as would be done with say a house or an office building. Don't go there. As I noted above, and as @GW implied, you are combining setbacks with a desire to heat the parishioners -- and you will need those radiators to be as hot as you can get them.

You are going to have some bad news for your vestry or other secular governing body, and I'm sorry about that. It is what it is. Just remember that having taken this on, your job is to provide adequate comfort for the congregation. Nothing more -- but nothing less.

JUGHNE

Was the steam piping removed also?

kcopp

Can you find some older cast iron radiators to replace it w? Craigslist?

Paul48

Now that the steam has been bastardized, the best way to heat it, on a shoestring may be hot air. Nobody is living there. It will heat the structure quickly, and there's no worry about frozen pipes. Don't crucify me, I didn't take the steam out.

Gordy

As much as we all hate forced air. I think as Paul said it is the best option unless ductwork is an issue. Especially with the setbacks. Does the church have ac?

Jamie Hall

Forced air certainly would have its points -- it's quick. Depends a lot, as @Gordy says, on whether the ductwork can be installed somewhere other than the chancel. Like a good basement.

Gordy

I think the risk, and control complexity of panel rads, and fin tube is cost prohibitive compared to forced air.well maybe not if the ductwork is a huge hurdle........

Forced air can give the parish the short term comfort it needs quickly.

bob_46

If you go with forced air pay attention to velocity and registers. It's hard to give a sermon over air noise or blower rumble .

L Thiesen

Just know that whatever system you decide to go with, some people in the congregation will be cold and some will be hot no matter what you do. In my home church on any Sunday a few people are fanning themselves while others have coats or sweaters on. It is impossible to please everyone with the temperature setting.
Also if you go with forced air set the fan on constant during the service so the sound system can be set for that level of background noise.

Bob Bona_4

Modern ac needs and the buildings use pattern make FHA the logical choice.

Solid_Fuel_Man

Forced scorched air pros: fast response
Forced scorched air cons: fast response, air movement