Engineering new steam system from scratch?

Chris Asmann

Hi there.
I've been on the mailing list and have Dan's books, but have not had the resources to do much more until now.

I see a few people here have built new steam systems, and I'd like to find out if there is someone working near me who would be interested in engineering and building a new steam system for me.

My house was built in 1840 and fitted with 2 pipe steam heat in the 1890's or so. HUD owned it for a while in the '70s, and every bit of accessable plumbing was stolen, including the radiators.

I have a non-functional undersized hot-water baseboard system in part of the house, and a nasty forced air furnace that(almost)heats 3 rooms on the ground floor.

I want to go back to steam heat that works.
My house is large (6300 sq ft) with 12' ceilings downstairs and 10' upstairs. I have no idea what it would (or should) cost to have a steam boiler and at least the first floor's plumbing and radiators installed.

Id like to have it engineered so the boiler is big enough for the whole house, but so we can get the core rooms heated this year and expand the system to include every room over the next year or two (or 5 or 6?)depending on the cost.

Everyone I've spoken to locally thinks I'm crazy, but they all live in modern houses.

Any and all thought on this are welcome.

Chris Asmann
Newburgh, NY

Steamhead (in transit)

Sure it can

and I know of someone in upstate NY whose old company did just that, though it was a one-pipe system. He now has his own company- Darin Cook of Thermal Perfection, he's up in Scotia so you'd have to ask him if he comes down that far. Here's the URL to his Find a Professional ad:

http://www.heatinghelp.com/getListed.cfm?id=509&Step=30

and for the job:

http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=269585&_#Message269585

Hope this helps!

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Leo

Mad dog has doen it

Mad Dog did it in his house and talks about it in his Find a Professional ad.

Leo

scott markle_2

steam vs. water

Steam heat is very interesting and many fine systems have been replaced by inferior scorched air systems in the name of progress. If you had a steam system in place that needed rehabilitation, fixing it might be an better idea than some might recognize.

If your radiators and piping are gone than you are starting without what would be a compelling reason to consider a steam system.

I have installed new burnham cast iron radiators in historic houses largely for aesthetic reasons. They just seem to blend in, in older houses. New, these radiators are quite expensive, While salvage is an option, handling, pressure testing ,lead paint striping etc. can make this very expensive as well.

If the cost of cast iron is acceptable to you than you may want to rethink the the steam part as well.

As ingenious as steam systems may be, there are things that a circulating water system can do that steam can not. Steam is essentially an on/off system. Most hot water systems are also often designed around essentially on/off controls as well. Essentially a circulator is turned on when a thermostat calls for heat and turns off when it is satisfied. While most conventional american residential systems operate in this way, there is a better way. One that is not an option with steam which must operate above 212 deg. to operate at all.

In essence these systems adjusts circulating water temperatures to match the heat-loss of the structure. Unlike a typical on/off system which operates at one temperature these systems are capable of adjusting circulating temperatures. Many are designed to circulate water continuously (or near continuously) during a heating load.

The advantages of this approach are multiple. Perhaps most important is the well recognized energy savings. Analogous to cruise control vs. one position accelerator, this system avoids the sine wave temperature fluctuations that are typical of conventional systems. Comfort is also improved, instead of radiators (and rooms) that are continually heating up and cooling off ( on/off cycling of thermostats)radiators maintain an even output, only becoming as hot as required by outside temperatures.

Basically you don't need steam to enjoy the comfort of a cast iron emitter. Modern circulating hot water systems will use less fuel, be silent, and may by more comfortable as well

Steamhead (in transit)

The myth refuses to die......

Where is the apples-to-apples, scientific comparison to back up the urban legend that "hot water systems will use less fuel" than steam systems?

So far, no one seems to be able to find it. If you do, please let me know.

As far as noise goes, a steam system should be as quiet as a hot-water system. If it isn't, something's wrong.

Chris, just how much piping is left? I bet a good portion of it was not so accessible to scrap thieves during HUD's typically neglectful ownership, and may still be there. Depending on pipe sizes, it would have been either a 2-pipe air-vent system or an early Vapor system. If the radiator supplies are all 3/4-inch or so, and the returns are 1/2-inch, it was Vapor. If they're larger it was air-vent.

Now here's a key point: Start your system design with a room-by-room heat-loss calculation- AFTER you insulate, weatherstrip, replace windows etc. Done this way, the radiators will look positively Lilliputian, but they will work amazingly well. Ask me how I know that.....

Many buildings today are over-radiated for their current heat loss, because they were insulated, weatherstripped etc. after the system was installed. Yours need not be. Smaller radiators, pipes, boiler etc. cost less to buy and operate.

If you're going to use salvaged radiators, steam has another advantage over hot-water: it runs at much lower pressure so there's less chance of a leak. Residential steam heating never runs at more than 2 pounds at the boiler, and Vapor runs at less than a pound- maximum. Hot-water, on the other hand, requires 12 pounds in a 2-story building, 18 in a 3-story and so on. This higher pressure WILL find any weak points in piping and radiators.

How about posting some pics of what you have? Let's take a look at it.



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scott markle_2

myths?

Is it a myth that a boiler operating at 140 will use less fuel than one operating at 180? This is something I have accepted as a fact. It makes intuitive sense to me that a higher delta between flame and water will allow more energy transfer and less heat up the flue.Not to mention less cycling when loads don't require 180.

Condensing boilers go a step further and can capture the latent heat released when flue gases condense.

How can a boiler that can only operate above 212 be as efficient as one that is operating at 140, or even below 100 for a condensing unit?

While a scientific comparison of steam vs. water may not exist. I'm sure there is documentation on the fuel saving of constant circulation, outdoor reset, and condensing HX tecnology. Steam cant do these things so how can it compete? Help me understand what I'm missing.

Steamhead (in transit)

The point is

as far as we know, there has never been a scientific comparison. Anything I've seen so far has been fatally flawed, therefore it is a myth.

For example, a while back someone was trumpeting huge savings when steam systems in some schools were replaced with hot-water. But when I read the fine print, in the only case where the condition of the old system was mentioned at all, I saw that the steam boilers were being turned on and off MANUALLY! This shows a complete control system failure. Obviously the existing systems had been totally neglected (which is typical of school systems) and that's why they were running inefficiently. Yet you had to really dig to find this. I'd be willing to bet the same thing happens with the hot-water systems, only the failures will probably be more catastrophic since a hot-water leak will probably cause flooding. Mod-con boilers typically need a higher level of care than cast-iron ones, and if the old systems weren't properly cared for these won't be either.

We can't call the difference in fuel consumption between a completely neglected steam system and a new hot-water system a fair comparison. It is not, never was and never will be. To make a fair comparison, we have to have both systems in the same building, properly sized, with similar boilers and both in optimum condition. As far as I know, that has never been done.

And, if you think about it, the water temperature situation you mention at the boiler is reversed in the rooms. The higher delta-T between the steam and the room air would increase the heat transfer. Piping losses on the way to the rooms are stopped with proper insulation. This last point is, of course, true of any system.

I suspect, although (full disclosure here) I have no numbers to back it up yet, that much of the efficiency of a mod-con comes from the varying firing rate. We can do pretty much the same thing with steam. We hooked up a lo-hi-lo gas train on a large Broomell system that previously only ran on high fire, and of course the boiler was oversized as well. The system now spends most of its running time on low fire, and the owner provided us with numbers this past summer showing a 40% fuel savings over the previous winter as a result of the change.

Don't forget, steam heating was originally designed to operate with the constant heat and long cycles of a coal fire. When burner makers get serious about bringing lo-hi-lo technology to residential oil and power gas burners, I believe we will see some major fuel savings. The first such burner in Baltimore will go in my house.

And a steam system has far less risk of freezing and bursting than a hot-water system does. In the coming era of Enron-style fuel and power interruptions, this will be an important factor.

So we can't give up on steam.

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Perry_3

What about a vacume system

Some of the more advanced steam systems were vapor systems that operated at a vacume. Steam temperatures about 150 F (or even lower) were possible.

I have long thought about what system I would put into an older house that I was going to renovate (stripped to the studs). I have not ruled out Steam - especically a vacuum steam system.

One of the efficiency advantages that steam has over hot water is on electrical consumption. Those Cicr pumps eat energy. While it is true that I cut my gas consumption by 45% putting in a Vitodens 200. It is also true that my electric bill jumped about $12 for the constant running circ pump I now have (before the circ pump only ran intermittently).

Of course; in a vacuum steam system I may well have an electric vacuum pump that would be needed for intermittent service. I do note that a good vacuum system would be a sealed system. Once the air and non-condensible gases are out of the system their should be no need for makeup water or additional vacuum pumping.

On the other hand... I do like cast iron baseboard and Monoflow T systems too....

Perry

Ken_40

I suspect these two simple facts...

that make "Where is the apples-to-apples, scientific comparison to back up the urban legend that "hot water systems will use less fuel" than steam systems? So far, no one seems to be able to find it. If you do, please let me know." disengenuious in that no condensing boilers exist that are steam, is one. The ease with which we can zone entire areas would be second - in proving water is inherently more efficient than steam. Your school example aside (which has no bearing on the comparison at hand), is valid; in a school. Just not in this instance where the rads and rad piping are no longer in place. I can see the PEX home runs from here...

Unfortunately


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Steamhead (in transit)

I'd forgotten that

parasitic circulator loss. Thanks, Perry.

And you can use cast-iron baseboard with steam, at least Burnham's version. A Tudor system with Burnham Baseray would be a thoroughly modern Vapor system with a minimum of moving parts.

Dunham once produced a Differential Vacuum system for residential use, and I know of one in Huntsville, Alabama that still exists. The pump would, of course, be a parasitic load, but once the air was out and the system was properly sealed, it wouldn't have to run any more that day.

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Steamhead (in transit)

Until the numbers are in

all we have is speculation. And don't forget that TRVs let you zone any system room-by-room- the ultimate in zoning.

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scott markle_2

speculation

Is it speculation that low(or variable)temperature systems are more efficient? I believe this is well documented.

Yes, steam systems were designed in the age of coal the thermal mass of those huge iron rads helped keep the house warm into the night after the coal fire died. Even with modern controls these systems are either making steam or not, sure bing bang controls work, but the thousands of overshoot undershoot cycles do effect efficiency, The evenness of full reset control permits a lower average room temperature while maintaining comfort.

Your point about delta of room air and radiators is interesting, and yes steam rads. could certainly be sized smaller because of this. However there is a big difference between the "efficiency" of an emitter HX and a boiler HX. Heat that is not given up to the room by a radiator will be returned to the boiler, heat not absorbed by the boiler HX goes up the flue.

I can see the pex home runs from here as well,.. actualy I'm not that far from Newburg. If you should come around on the idea of steam feel free to give me a call. 845 687 9872

ER

I think the comment that there has not been any clear example of efficiency difference between steam vs hot water is amazing. Yet at the same time not so surprising.

I would strongly suggest contacting the Building Technology Center at Oak Ridge National Labs.
http://www.ornl.gov/sci/btc/
Most of the lab is developing nuclear bombs but they have a small section that actually does something useful. Glancing over their various publications this sort of thing seems up their alley.

In terms of efficiency it would be nice to see a head to head study in new construction.

But really the question is "should i rip out my old cranky steam system and replace it" which is darn hard to answer, But I'll bet you could come up with something.

Eric

Bruce M

Steam systems from scratch


I will see that Darin reads this thread.

He has family sorta' down that way.

Mark H

Chris Asmann

What a fantastic influx of great thoughts!

Thanks to everyone who replied!
I don't want to set anyone at odds, but I have a some strong opinions of my own too. I am so glad to have found this resource, and all of you.

Now I'm not a heating professional I'm just an old-house homeowner. I can do many, many things well enough to get by, but not many better than that. I'm interested to hear all the pros and cons from everyone with any experience. Efficiency is always top priority, I hate to waste anything even if I can afford to pay for it.

I will only do this once (like Daffy's trick, there is no encore). I'd like to hear every opinion before deciding. Maybe there is something that will work better in my house than steam, but I think a professional would have to see my house first and give it some serious thought.

I have done whatever I can to better insulate, including replacing beloved old-glass windows with new energy-efficient ones. I still have significant air movement throughout my home, which is not necessarily bad. Mostly it is not outside air, but currents within the house set off by sunlight coming in some windows, and cool plaster and masonry walls. plus a 28' center hall with dome and oculus that encourages hot air to move upwards.

I have a few reasons for wanting steam, none of them nostalgic. I have seen modern steam systems in my family's homes in Germany that did a great job and were very efficient. Fuel of every sort is rediculously expensive there. Their modern steam radiators (dunno if they're available here or not) were small and unobtrusive, not to mention quiet. I never heard hissing, hammering or saw any visible steam.

Forced air is a joke, and I have lived with it long enough to know. It dries my walls, woodwork, furniture, hair, skin, etc. Crappy Newburgh water means humidifiers are as labor-intensive as the coal fires I use for heat right now.
Lets' not mention all the differnt filters Ive tried, the dust and the returns I can't keep clean.

Hot water seems like a great idea for a small house. I have hot-water baseboard that leaked and the results suck, Besides the fact that it was never warm and ran 24 hours at an unbelieveable cost. Maybe larger hot-water radiators are better, but then you have much more water circulating. What I have of the hot water had 4 or 5 electric circulators, and it lost about 5 gallons of water every week it operated. (less maintainance than coal fires, by about half). I wonder about the thermal mass of all that water...can it cost less to heat 50 gallons of water to 140 degees than it does to heat 2 gallons to 220 degrees?

How much of the water gives off it's heat to the iron as opposed to the steam? 50 gallons of water at 100 degrees as opposed to 2 gallons at 180 degrees? After running a while, does it even out in cost? Surely a hot-water system needs electricity to circulate, an additional expense and additional maintainance. I need some hard data for both options.

My neighbor has a house about 2/3 the size of mine, and she had steam converted to hot water. You should have seen what happened when a third-floor radiator 'accidentally' split apart (froze maybe?). the idea of that really scares me. To have water damage like that on a day when you're not home could ruin your whole winter, and/or get your insurance permanently cancelled.

I would need a compelling reason to choose a few hundred gallons of circulating water instead of relatively dry steam. Remember I have 17 rooms, and 6300 sq.ft. Someday I'd like the option to heat it all, even if I only do it on my birthday.

I will go take some pictures of what's in my basement once I get home tomorrow, see if I can upload them. There is not much to see. a dead hot-water heater, a forced-air box and two water heaters. a wall full of electric circulators.

The existing steam plumbing is various sizes. Where there were radiators (for certain), the holes are exactly 1 1/2" across. Pipes look to be 1", same on both sides. One pipe on each end of the radiator.

I have many remnants of gaslight pipes, and of gas pipes in the fireplaces too. Black pipe is everywhere. There is some bronze too, but I think that was drinking water only.

I'm figuring none of the old plumbing is salvageable, but it would be a pleasant suprise if I was wrong here. I have no surviving radiators either. And I also have no idea what the differnce in cost would be between the different options. I know it won't be cheap no matter which way I go.

I'll be re-reading all the posts tonight, and I can't thank you all enough for your input. Here is a link to my web site which hasn't been updated in about 5 years, but has a few pictures- http://the-tuscan-villa.com

And here is the link to the HABS report on my house:
http://hdl.loc.gov/loc.pnp/hhh.ny1245

Maybe I AM crazy, on second thought.
Chris

ttekushan_3

steam circulation

Consider that the high delta T at the boiler is compensated to a large extent by the fact that the high delta T at the radiator extracts the latent heat from the steam, creating a vacuum that causes steam circulation. There are no circulators on steam systems because of the very fact that a cool radiator creates the circulation. This is why I can go into a three floor apartment building with commercial retail spaces on the first floor, balance the system and get the result of even heating even though there are NO zone controls of any kind. When a retailer's front door opens and closes, the cold air cools the radiator and PRESTO! the cooler radiators condense more steam creating greater vacuum (this occurs at the condensation surface,i.e. the film layer at the inner radiator surface), shifting the balance of heat flow while the temperature imbalance exists. This example illustrates why steam circulates without external force. The force is caused by the requirement for heat.

The pick up factor is there to purge air and preheat supply pipes. Stage fired boilers with a modest turn-down ratio are wonderful for eliminating the pick up factor once the system is primed.

Furthermore, steam doesn't return to the boiler with latent heat unused. If a steam heating system is going to deliver heat, it sure isn't going to return with most of its heat content unused! There is no waste of moving tremendous mass around the tracks delivering small amounts of heat on each trip.

Funny thing about the early days of coal-fired steam heating systems: they were NOT on-off affairs in the least. Vapor, vacuum, huge effective turn-down ratios (as the coal burned down), etc. were the rule of the day. Cheap gas and oil and cheap intermittent firing boilers did the damage. Post war boilers became more of commodity with both hot water and steam systems suffering for it. Industrial clients would never tolerate single stage firing; they didn't and don't. Too wasteful. But the homeowner was expected to tolerate it.

Finally (almost), steam heating systems were typically installed in an era where radiators were oversized by today's standards. I think they had good reason to do so at the time; yet these systems can be tuned and staged fired with fuel usage numbers that are quite competitive with "modern" systems. How is this possible? How about a new steam heating system that is sized to today's heating requirements? Glad I asked. See the attached thread from heatinghelp archives.

You can't look at boiler AFUE numbers and then make broad inferences for heating costs without taking into consideration that steam is a thermodynamic heating method and all others are NOT. Its well established that the most efficient heat transfer is latent heat in vapor form. Just look at the COP of refrigeration systems. The big difference in SEER is only due to compressor design.

Beyond this, the myriad of controls, mixing valves, zone valves, sensors, thermostats, etc. etc. require a good deal of energy to make and a good deal of money to replace when they fail. Once the budget is large enough for all of these necessary things, you may as well purchase an economizer or recuperator for your steam boiler and be done with it. Economy of operation in both fuel usage, service costs, longevity, and comfort result. A good definition of efficiency, I'd say.

Terry

ttekushan_3

Just looked at the HABS


BTW, the larger the dwelling the more steam works to your advantage. You can zone steam, especially if using either a)steam boiler with higher turn down ratios (several firing levels) or b)multiple steam boilers, firing based on demand.

And cast iron radiation really does help reduce floor-to-ceiling temperature differences.

I may have missed it, but do you plan to fire with oil or gas?

Terry

Perry_3

Things to consider

In order to sucessfully implement what you are planning you will need several items:

1) Buy two copies of "The Lost Art of Steam Heating" from the store on this site. You may also find some of the other books interesting as well.

The reason that you need two copies relates to Item 2.

2) You will need to locate a heating contractor who has at least some glimmer of knowledge on Steam .... AND IS WILLING TO LEARN. Don't hire them unless they are willing to study and read the book you are going to lend them.

3) A large pile of cash; or alternately some personal skills in mechanical work, a willingness to learn, a helper at times, and lots of time to run pipe. I believe the old rule of thumb was something along the lines that it took a 3 person crew 1 day to run the pipes and install a single radiator in a room (when building a house).

You may have more or less time invested depending on the conditon of the pipes in the walls (it will take time to tear out old piping).

If you are hiring the job done; figure a minimum of $1500 per normal workday for a 2 person crew with tools (and this could easily be $2500 per day depending on location).

4) If I was starting from scratch I'd use the cast iron baseboard that SteamHead mentions. That allows better layout of furnature and things in a room without having to work arround the old standup type radiators. This is not cheap; but it is probably cheaper than modern versions of stand up radiators and is still in production.

Given that you will be insulating the house it will probably also be easier to match how much radiation area you need per room.

5) While I do admit that steam has many advantages; please keep in mind that a proper hot water system would also work very well (and keep the house warm). I have cast iron baseboard hot water in my house and do not suffer from lack of heat (the 50+ year old radiators look similar to the cast iron baseboard radiators that SteamHead mentions). I'd personally run a copper 2 pipe system with individual TRV's and a single circulating pump with a modulating condensing boiler (and a Pristigue, or Vitodens 200 would work well and probably provide long term durability).

If I were starting from scratch.... in a large house. It would be a serious debabe between hot water and steam. Both will keep you equally comfortable as long as they are properely designed.

Perry (homeowner)

scott markle_2

interesting

Terry, I'm intrigued by the self regulating behavior you describe relating to the rate of condensation at different radiators.Cool

The whole thermodynamic phase change, latent heat thing is fascinating to me as well. My own interest in this has been focused on condensing boilers.

The important distinction between a condensing boiler and a steam system is where this latent heat is coming from. A steam system uses this thermodynamic principal to move heat efficiently from one place to another. A condensing boiler is recovering latent energy from combustion. The byproduct of hydrocarbon combustion is mostly water vapor, if this vapor is cooled to it's dew point within the boiler heat exchanger we are recovering the energy that is released in this thermodynamic phase change in addition to a very high thermal conversion of the fuel. Theoretical efficiencies over 100% are possible because btu fuel ratings don't include this latent energy.

As far a I can tell the primary advantage of steam is the efficiency of it's distribution, and the lack of water to freeze.

Aside from pumping costs how does the thermodynamic principal of steam distribution effect efficiency?

If your current system runs continuously and is unable to heat the space don't expect a miracle from whatever system you chose to install. The bottom line is that It's probably going to cost a fortune to heat the house even at the highest achievable efficiency.



I was curious about the topic pdf.but it didn't load for me

ttekushan_3

Here's a link to the thread

this should work:

One
pipe steam success story

Oh how right you are about the number and quantity of radiating surfaces! I tend to forget sometimes that the most important thing in a heating system is good design and execution. Of course, when a heating system gets as old as most steam systems are, the design is usually good, but the ravages a ill-advised "maintenance" over the years severely compromise the original execution. Actually, this holds true of everything. How many times have we walked into some form of steam or HW heated buildings and said, "Good Lord. What have they done to this system"?

Your point about the condensation of flue gases is key. My understanding of what makes continuous circulation desirable is it a) acts like high-mass radiation even if there are no high mass radiators and b) the continuous circulation allows for lower supply temps that translate to lower return temps allowing the boiler to condense combustion moisture. The latent heat's where its at!

I'm thinking that a high delta T is not necessarily a problem, as long as a source of cool working fluid encounters the flue gases. Continuous circ low temp operation allows for a single handy-dandy condensing boiler to handle all operations in one self contained unit. Compact with great efficiency numbers. The condensing boiler has its ECONOMIZER BUILT IN.

With steam, its a discrete device and never included in boiler efficiency ratings. Never mind the fact that historically no such economizer has been made for smaller heating applications. What's interesting is we're finally seeing small scale devices both flu gas-to-water and flu gas-to-combustion air (usually called a recuperator) that can be used with a power venter on existing boilers. I have no idea why a flu gas heat exchanger, make-up combustion air heat exchanger, and return liquid-to-liquid heat exchanger connected together in a HW loop is out of the question.

Possible exceptions: Korea Miura now makes water tube steam boilers appropriate for space heating with an integral economizer, and high turn-down ratios. Efficiency claimed to be 90% or so. The smallest models can turn down to about 2.5 HP (86,000 BTU output). Automated blow down. Since these are once-through boilers of low internal mass and water content I'd imagine that AFUE would look good.

check these out, at least in concept:

Korea Miura

to be continued. . .

JohnNY

With all due respect, Steamhead.

This statement:
"The point is as far as we know, there has never been a scientific comparison. Anything I've seen so far has been fatally flawed, therefore it is a myth."
puts the validity of your whole argument in question.

You may have your doubts and your points may be compelling but to call this a "myth" suggests you have scientific evidence to the contrary. Which you admittedly don't.

There is an episode of This American Life (search iTunes) where a man INSISTS he has disproved Einstein's theory of relativity.
Scientist after scientist try to explain to him where he's just dead wrong. He's buying none of it. He never will. He likes his argument.

I hope nobody ever wastes time and money on a study to find out which is more efficient: steam or hot water.

Just my humble opinion.

I fully acknowledge that you are a seasoned expert in the industry, possibly without peers.









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ttekushan_3

wastes of money

Although this statement wasn't sent in my direction, studies and experiments to verify hypotheses are rarely a waste of money. Unless, of course, one considers verified knowledge to be a waste --and that myth will suffice.

Its post Enlightenment now. Was all that energy, time and money spent on scientific inquiry a waste? Someone else's waste is my investment, I guess.

As I said in another post:

"I find it odd that no studies of any statistical validity exist on this issue, especially in light of the fact that steam district heating systems all over the world are being expanded in the name of efficiency. Steam's low mass, high heat capacity, and low reticulation costs overcome many of the shortcomings that occur in the boiler room.

And boiler room / flue losses are not a technical problem by any means. Its all cost/benefit as with everything else. If you look at expected in-service fuel savings against life-cycle costs that take into account both expected service life and the "embodied energy," of existing and durable systems, the stated benefit of replacing serviceable equipment becomes quite questionable. Additions of economizers or recuperators to existing equipment might make more sense in the final analysis. Everything from replacing heating systems to windows should be subject to such scrutiny."

There is plenty of scientific evidence to support "efficiency" claims of all the current heating media. Some of us have experienced it directly by keeping track of MCF or therms used per degree day. But until an official study is performed, the real evidence that experts in steam heating see again and again is considered merely anecdotal.

Such a study would be outrageously cheap to perform considering our GDP and the size of the heating industry. What could possibly be so threatening to anyone about knowledge so gained?

-Terry

Steamhead (in transit)

I disagree, John

I think you've missed the point, which is, that until such a study is done, we really don't know for sure.

Unfortunately, there are many instances these days where speculation, conjecture, opinion etc. are passed off as fact. Why should we do this in our industry?

An example of a verified fact is the savings achieved when an old-style oil burner is replaced with a good flame-retention unit in the existing boiler. Since the flame-retention unit burns with less excess air, it won't waste so much heat up the chimney. A further savings occurs because the flame-retention burner, when properly set up, will not soot up the boiler. In this instance, assuming the installation does not include flueway baffles, a new firing chamber or something else, the burner is the only variable and is thus responsible for the savings. This has been proven again and again.

You will note that Gordon and I never post any fuel savings where we don't have the numbers to back it up. You want numbers from us and how we achieved them, you got 'em. We would never think of doing otherwise. We don't think it's a waste of time or too much to expect.

I would say to the guy who thinks he has disproven Dr. Einstein- "We have Einstein's numbers, and we know how he arrived at them- show us yours". Sound familiar? Not sure if any of the scientists you mention has tried it this way though....

Terry, you're absolutely right. Verified knowledge is never a waste of time.

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Mad Dog_2

We consult up yonder.....................................

And Darin can do the install....good chance to see my old friend again. John NY and Steamhead...I love Ya both. Mad Dog

Mad Dog_2

Thanks for the Plug Leo........

Did I tell you my middle Name is Leo? Mad Dog

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Mad Dog_2

Excellent suggestions, Scott

But Steam head makes an excellent point: You'd think after all these years there would be an "apples-to-apples" study., to shut one side up - hasn't been. Mad Dog

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Mad Dog_2

STEAM IN GERMANY?????????????????????????????

"They've" told us it was outlawed YEARS ago...after We bombed them to oblivion. I had an inkling there HAD to be plenty O' systems still cooking. The Family and I will actually be going back to The Fatherland next year...so I will see for myself. Chris, if you are NOT in a rush.......you can get all the real-time, real-life experience you will ever see in one place - here at The Wall. Then, you can make a REALLY informed decision. Mad Dog

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Jamie Hall

too many variables

to make a good comparison. It would have to be done in a lab. setting, and it would be fascinating.

As to the 140 water vs. 212 steam vs. the flame temperature. Um. Well, keep in mind that the flame temperature is around 1,000 plus; the difference in cold side temperature is trivial (and a good bit of the heat transfer in steam is at less than 212 anyway).

One could build an exhaust condensing steam system: use the exhaust flue gas in a feedwater heater. No big deal. I doubt very much that the cost would be recoverable.

As several has said, the real key is zoning -- which is just as easy to do with steam as with hot water.

scott markle_2

is it trivial?

I'm not convinced that because the delta between flame and HX is so high that we can infer that a 40 degree drop on the cold side is trivial.

Why have we been hearing so much about the benefits of such reset strategies even in non-condensing partial reset applications?

While the reduction of cycling and steady state efficiency are certainly part of the benefit, it has always been my assumption that less heat up the flue as a result of more efficient HX was a big factor.

As far as zoning with steam,what if trv's are all closed? What is the steam equivalent of dead heading? Is full zoning really as easy as you suggest? I certainly don't pretend to have a working knowledge of how steam systems operate. I assume the boiler is regulated by steam pressure and demand for heat. If trv's were highly restricted wouldn't this result in inefficient short cycling.

ttekushan_3

HX delta T, closed TRV's

Lets see.

We know that high delta T gives high HX heat transfer. Or does it? At first glance I’d say that lower flame level would give a lower delta T and therefore less heat transfer from flame to water. But there’s more to it since the burner modulates both flame and draft, so the TIME the heat spends in the chamber is longer. It seems that the flame/HX interface has a “sweet spot” where the non-condensing operation is most efficient. And that would be at partial loads at least where modern low mass mod-con HW boilers are concerned. Operation with outdoor reset keeps the firing rate as close to optimal as possible by manipulating length of cycle and target water temp whether condensing or not.

I have to remind myself that we’re dealing with the amount of heat transferred and not necessarily with temperature. Here’s a critical difference between the behavior of water and steam: Assuming all other things being equal (and both HW and Steam boilers modulate), a higher firing rate with HW results in higher water output temperatures but leaves output volume unchanged; a higher firing rate with steam increases steam output volume but leaves output temperature unchanged.

Therefore, the HW boiler firing rate relates to output temp, the Steamer’s firing rate relates to pressure. Attaching the boiler to pipes and radiators, a temp sensor tells the HW boiler what's going on, the pressure gage tells the steamer what's going on. The point is, lower firing rates on a steamer increase TIME the flame spends in there just the way it happens with HW. Only delta T from flame to HX remains the same.

So if all the TRV’s close on a steam system (with modulating boiler, remember) it will cycle, but only after its reached its lowest firing rate for awhile. If the TRV’s remain closed, and pipe insulation’s pretty much intact, that boiler could be “off” for quite some time. I looked at one that pretty much held pressure under those conditions for about 7 minutes. But there’s nothing in the rule book that says an electronic steam boiler control should be oblivious to extended pressure shut down.

Case in point:

A very lovely elementary school, about 1930. Heat was turned off overnight, weekends and holiday periods. Individual room controls were pneumatic t-stat and actuators. A new (at the time, 1999) pair of Kewanee 100 HP fire-tube boilers; Vacuum return; Turn down to 20%. Firing sequence: Boiler 1- 20% fire shock-protect warming (until 200 degree water temp), increasing firing rate over a period of about 20-30 minutes (not sure) until 80% fire (20%-80% being the best efficiency range). If 80% held for a significant amount of time boiler 2 would initiate firing, mirroring the operation of the first. In tandem they’d hold at 80% and if demand wasn’t still met they’d both fire to 100%. This rarely happened. Then they both turned down until 40% tandem firing was held, then the first boiler would shut down. Once the remaining boiler turned down to 20% and held there for a while, or pressure shut off was reached, the boiler would NOT restart until the outdoor sensor told the controls to restart the sequence. So no dead-head problem here. Throughout the day, only one boiler typically fired. But bitter cold January temps after the Christmas break are a different story!

Why no such control exists for small steam boilers I can’t really say. The same question goes for residential modulating steamers. But I see no reason why we can’t have a basic outdoor reset control that could both operate on time/outdoor temp inputs but also be able to reset the cycle clock based on pressure cycling. I saw it operating on a large scale heating plant. Would it really be THAT difficult in this day and age to make a small, affordable one? I think not.

-Terry

P.S. Flue gas condensers or condensing economizers for steam are quite possible for small scale steam heating. I’d like to see what a boiler manufacturer could do with this. Until we know what a production version would cost, its hard to tell if its will or won’t pay off.

Darin Cook_5

Steam from scratch update

When I was serving in Iraq, Mark H and our guy Mike W installed a steam heating system from scratch in a beautiful home built in the very early 1900's. The only thing reused were the steam radiators from the original system. The owners chose to go the steam route to keep the heating system in the same era as the home.

After a season of heating use, the owners would like me to design a htg/clg forced air system utilizing heat pumps. Two reasons for this: one being to have central air conditioning to combat our hot, humid upstate summers and the other is that during the shoulder seasons the steam heat roasts them out of the house. They absolutely love the steam on those frigid winter days.

There was alot of interesting points brought to light in this post. I will ask these customers if I could see their utility bills from when they had a forced air system heating this house to when they had this steam system installed. It should be interesting.


P.S. Thanks for the referral Matt!! We still have to do that deep sea fishing trip!







Darin

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Steamhead (in transit)

Darin, the roasting

is a control problem. Check the burner cycling adjustment.

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Mad Dog_2

Yes we do....

Hope you ain't working this weekend. Mad Dog

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Chris Asmann

Busy week, need a little more time

Gentlemen, I'm sorry to have been absent from the discussion for so long, especially after starting it in the first place.

I still haven't gone downstairs and taken any pictures to post, but I will do that over this weekend. I really appreciate everyone's input.

A few years ago a friend of mine who does AC work suggested I try forced air using little ducts with fans in them.

This could solve the problem of huge ducts all over (did I mention that my house is plaster over solid masonry (no lath except ceilings)? But I don't like the idea of all that electrical wiring. And I would still have the dirty air/dirty returns problem.

I'd like to know more about the people who changed their minds...How it went, what they did, what it cost, what they had before, etc. Were their old radiators just too big for the house with newer insulation? Or did they just want one system that could also provide central air? Are their pockets deep enough they can afford to just make changes like that to see if they like it better?

More food for thought.
I'll be able to post picture and address all the input better in the next coup[le of days.
Thanks again everyone.
Chris

Steamhead (in transit)

\"the dirty air/dirty returns problem\"

is one big reason not to use forced-air.

Another is that the moving air makes you feel chilly in the winter.

Since you're starting from scratch, radiator oversizing shouldn't be a problem ;-)

Trying to combine heating and cooling in one system never works that well. Most of your heating load is on the lower floor but most of the cooling load is on the top floor. Such a system is out of balance at least half the year. Also, if the total heating load and the total cooling load are not roughly the same, the ducts, fan etc. are oversized or undersized half the year.

Combine this with the fact that the typical duct system loses something like 20% of what goes into it. You can't achieve any kind of fuel-efficiency this way.

It sounds like your house has lots and lots of thermal mass. You might look into furring the walls out and blowing insulation into the resulting gap to isolate this massive heat sink. Then you can use even smaller radiators.....

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Steamhead (in transit)

They sure did

and I'm sure some of these are still there, also in France, despite Allied military prowess in WW2.

I believe Viessmann and Buderus still make steamers for the German market.

Check out this link:

http://www.heatinghelp.com/pdfs/492.pdf

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