Steam- Hydronic efficiency

Unknown

We know steam heat was popular in the time when homes were not built for lower heatloss ( no insulation , leaky windows and doors ) . We also know that many of these homes were upgraded with insulation and new windows , doors . Radiators were usually oversized for the home then , and grossly oversized for an insulated house now .

Has anyone ever replaced a whole house of radiators with the proper size needed after insulation ? I wonder how the efficiency numbers would stack up against converting the home to hot water ?

Ken D.

Efficiency - steam vs. hot water

I know I can get good answers here. In your opinions, what is more efficient overall? Steam or hot water? This is assuming a heat only residential- commercial system with identical boilers and with identical combustion effiency. Take into account real world maintenance and repair issues over the life of the system. Thank you.

Jerry_15

Are you talkin new here? Piping costs alone would kill you; or converting a two pipe steam, or gravity system to forced hot water. In Europe, where district steam is available it makes sense. But on a single family residence on a new installation, yikes! Snap out of it!!!

Brad White_40

Water gets the edge.

(Speaking of houses here, apples to apples you understand and both properly sized- hot water to the load and steam to the radiation and with steam radiation sized to the load.)

Nothing wrong with steam but out of the box, steam has to be 212F plus just to get it to leave the boiler on any day, any hour, any moment when the house needs heat.

Hot water can modulate in temperature between what is needed by design on the coldest day (usually 180 in conventional systems and much, much less, 120 degrees or less, in a condensing boiler system.

The water can circulate constantly to maintain heat transfer effectiveness. But steam can move without a pump.

Further, the temperature can modulate across that range with the appropriate controls, tailoring output to the load. This is true of either conventional hot water or condensing hot water systems. It is for this reason that hot water reset is one of the first "add-on" control strategies to enhance the performance of an existing boiler.

Steam by it's very nature of control, cycles in operation whereas steady-state is accepted as more efficient, but some systems, large ones that I know of, do modulate within a range. Hot water systems properly sized and with modulation can control between 100% input down to 25% input usually. Hot water boilers with on-off control will cycle more as weather gets warmer, just like a steam system.

Combustion efficiency principles also mandate among other things that you should have as narrow a difference as possible between leaving flue gasses and the leaving medium of the system, be it steam, air or water. With steam your flue gasses will be in the 300-350 range at best and often higher.

With hot water you can have flue gasses barely ten degrees warmer than your leaving water. Sometimes less.

Steam is great, don't get me wrong. I have lived with both and miss the deep penetrating heat that welcomed me in the AM. As a landlord I had both side by side in a multi-family, each new boilers hooked to existing systems properly sized. When paying for the operating costs, the steam cost more to run. During the coldest months the gap was less and in warmer months it widened.

Granted, we did not have HeatingHelp.com -back in the old days, by cracky- and I probably could have cranked it down (ran up to 3 psig with a cut in of 1 psig, did not know better). But at least the pipes were insulated.

Typical steam efficiencies (AFUE numbers for what they are worth) run in the 80 to 82% while water is a point or two above that. When you go to condensing hot water with gas, this edge jumps to the 90%'s. Your initial premise of "identical efficiencies" is not operative unless the hot water system is mis-sized or mis-managed, typically.

My $0.02

Brad

Steamhead (in transit)

Brad, your second-to-last paragraph

says it all. The steam system in question was not running at its best efficiency, so of course it cost more to run.

Another point is that there is much less water in a steam system. This at least partially offsets the need to get the water to boil.

And a steam system is much less prone to freezing in an extended power or fuel failure. In your side-by-side comparison, the steam system might develop a leak in the wet return in the basement, but the hot-water one would probably be a total loss. Sure you could use antifreeze in the hot-water system, but that would be one more thing to maintain and might run into environmental restrictions in the future.

Brad White_9

As always, Steamhead you are right

Your point about not freezing is of course excellent and having had my boiler with a standing pilot, I had heat when the lines would go down in an ice storm.

My energy costs would have been closer I am sure but the hot water had reset (agreed, not a level playing field between the two). The steamer did work fine but agreed, could have done the same work for a lot less fuel.

The use of anti-freeze is to me the heating equivalent of a colostomy: It does what it is supposed to do, you would rather not, you have few other choices and of course always wish there was another way Another Brad White Analogy..

What is the "in transit" suffix? Are you on the road.... or having an "operation" of some-sort?

Joe Brix

Dont forget zoning

With steam it's all or nothing. I don't count thermostatic air vents since they only prevent overheating of a zone. Being able to zone individual rooms with hot water helps comfort and efficency over all.

Boilerpro_3

I greatly disagree

TRV's on steam can provide fully modulating heating of individual radiators, very similar to hot water. In addition, by varying pressure on a well balanced system with orifice plates in the supplies, you can provide outdoor reset to the system. The chief advantage of hot water over steam, is its ability to provide low temp radiant heat which creates less convection heating than the high temp radiant that steam provides. Also your supply piping loses are higher with steam, however, returns are nearly ice cold, so there are almost no losses here.
The end result is you have a steam/ vapor system with outdoor reset, Modulating output at the radiators because of the TRV's, substantial freeze protection, no electrical usage by pumps (an incredibly inefficient energy source), and excellent comfort. Its all a matter of applying the same depth of knowledge and understanding to steam as is now being applied to hot water systems.
Yes hot water has an edge, but a steam system installed with all the same goodies as a hot water system is far better than the typical steam system, just like the high end hot water system is much better than the typical hot water system. It like comparing a poorly installed hot water system, to a very good forced air installation. Comfort will be better and efficiency better, but you're comparing apples to oranges.
I find it funny how people say steam is too expensive to install. We are far more wealthy now than when steam was king, so how come no one can afford it? Labor is more expensive, but peoples incomes are higher.

Brad White_9

I agree, Boilerpro

Steam is not "all or nothing" and it can be made to work well.

What I love about this site aside from the give and take is that it is a "clearinghouse for misconceptions".

Steam today is "not your grandfather's steam system". On the other hand, maybe it really is! It was the son of your grandfather's steam system over the past 40 years where "crank it up", "tear off the asbestos and heat the basement" were the unfortunate malpractice that most people associate with steam today.

Ken D.

Steam- Hot water

Interesting discussion from the best. Thank you all.

Steamhead (in transit)

Steam can have reset

it resets time instead of temperature but can have the same effect. I have a Tekmar 269 out there that I really like. Stage-firing works well with reset to extend firing cycles, but is not yet available on the smaller boilers.

I am currently in the Providence, RI area, just finished a week of seminars at Tim McElwain's gas training center. When I get home and get caught up I'll post some pics.

Brad White_40

You are just down the road apiece

had I known I might have made a trip to meet you. Enjoy the trip and the wind! Stay warm. Brad

adayton_2

Hybrid Systems revisited...

Back to a thread I posed a week ago. Why not design a Hybrid system? a modcon steamer with a mid sized pot of water that would feed an exchanger for DHW AND feed an xchanger for judiciously placed radiant floor heat (underneath the first and second floors). The modcon coupled with radiant floors would be the known king of efficiency in the spring and fall and would always provide ample DHW regardless of OAT. BUT when the BIG CHILL hits then it would crank up some steam to much smaller newly designed wall panel (two pipe system) steam radiators (BUT could still feed existing old big radiators for backwards compatibility). The BEST of both worlds, Radiant efficiency (and COMFORT) and Steam Horsepower as needed (and COMFORT)..

Anyone up for a colaberative design effort? :-)....

Alfred

Brad White_40

The Curse of the All-Night Starbucks

Interesting proposal, Alfred... it is only money.

Of course you do know that condensing and steam are mutually exclusive on the steam side. But go for it!

But I do miss the hiss and ping of steam in the AM. It smells like.... Victory!

Boilerpro_3

You better take another look

at what's available. I understand at least Gas Master has a condensing steamer. I suspect they use the return condensate and /or incoming combustion air to condense with. My Dunkirk Quantum leap does that, as it appears the Big V too, so exhaust temps are well below return water temps.

Boilerpro

Brad White_40

I would call that partially condensing

a different animal. I did not mean that statement as an absolute, it can be done.

In commercial/industrial use we have used the first stages to pre-heat boiler feedwater (applicable to larger water-tube boilers some with stack economizers). With larger amounts of boiler feedwater, sure. But when condensate steady-state is coming back at over 180, condensing cannot occur. And in residential systems for the most part, I do not know of any. I will check out the Gas Master though. I always found their WPD to be quite high in their H2O boiler, maybe flash steam??

Thanks for the heads-up!

Brad

Christian Egli_2

Olympic fire in Turin and the hitherwards race for chocolate

Steam is incredibly more efficient than either hot water or air. In my opinion, though, I find that the measurement of percentaged efficiencies can be widely skewed in all twisted manners of shapes. You can get plenty books to learn how to lie with statistics and percentages, politicians make good use of these when producing tax rate schedules and other schemes. We all know how we all get fooled at the ballot box. You voted for a mere pennies on the dollar property tax increase and you just wacked yourself out of $ 25,000. Be careful with numbers.

Various government agencies come up with weirdly computed efficiencies which may all have sprouted from a good concept, but with the whole slew of them we've got now, you've got to scratch your head in wonder. John Runke of the RPA is rightfully worried the AFUE numbers do not work in favor of radiant floor heat. Do you think any of these numbers work in favor of steam?

Anyway, steam is so impressive on its own that it is truly hard to believe. We should pinch ourselves all together. On the count of three, one... two...

I've stuck probes in all sorts of flue and we know we get results for temperature that are all over the place irrespective of the type of boiler or furnace we're looking at. Poor or forgotten maintenance will destroy performance and maladjusted excess air and blower dilution will lull you into la-la-land efficiency readings. I don't want to compare a silted up steam boiler with a fully optimized brand new hydronic boiler, that would not be fair. So, lets look at a crapped up water heater compared to a super modern steam plant with all the economizer attachments we can dream of. Fair? I thought so... let's look at the concepts.

Where does home heating start?

Well, there's a fire which burns and gives off lots of heat. The residual amount of heat we harness is somewhat very much proportional to the step in temperature between the flame (on one side of the boiler heat exchange surface) and the heating medium (on the other side).

Top of the cliff: oil fire temperature, 2500 F in altitude. Jump off and hit rock bottom at: steam, 212 F, hot water, 180 (or so) F. Ouch, it's a big jump, it hurts a lot. But which hurts more? Falling from so high up, 2500 F, down to either 212 or 180? It does not seem to make that big a difference; you're likely to just splatter yourself in both cases. Stopping at 212 F would be like hitting a pebble rather than rock bottom. If you practice your jump and you cream yourself a little deeper down into the sand, the difference between 212 F and, say now a low, 90 F may seem like a rewarding effort but relative to where we came from, 2500 F, it is not all that significant. The difference you get in residual amount may float around 1%, 2%, 5%, 8%(tops) depending on heating medium and what fuel you burn.

Interestingly, a hot air furnace I have knocks itself out on over temp at 250 F. We can conclude that hot air is actually hotter than we think, at 250 F it is way hotter than either steam or water. Now, hot air temperature fluctuates a lot more, that changes things somewhat, but not enough to prevent furnace pushers from stating that their way is the best way. Hmmm...

The lower or hotter heating medium temperature makes a real difference indeed, and seemingly stacked against steam, but it's not like you won the lottery -yet- there's more!

We've looked at the temperature of what is on both sides of the boiler heat exchanger wall, but this is not enough to qualify our heating medium. We need to know more. Some fluids readily carry lots of heat, some less, some hardly any. What gives?

It was mentioned earlier that to make a hot water system freeze proof, the simple addition of antifreeze juice does the trick. The trick is, it also decreases the heat carrying capacity of ordinary water by a significant amount, enough to make this solution often undesirable. Water efficiently handles 1 degree F per BTU per pound. Working with the ubiquitous 20 F delta T, that leaves us with a carrying capacity of 20 BTU per each pound of water we shuffle through the boiler. And in relation to the antifreeze cocktail, we can be gravely concerned by any decrease in this number. Chemical science hasn't rescued us from this situation, and there is (no) hope of ever finding a beefier heat carrying liquid. Help! Heeeeelllllp!

Wait... look up... in the sky... it's flying... it's a crimson flash... it's a superhero coming to our rescue... it's... it's... Stupendous Steam! Ta-daa.

"Mr. Steam, Mr. Steam, will you help me carry away the heat from my boiler?

"Well, sure, son, how much is there to carry?

"Oh lots, there's all this 1000 BTU and more! All I've got is this watered down heating liquid that will only hold less than 20 BTU per pound. I'll never be done in time... Will you please help me, mister?

Imagine a little drum roll and some sound effects here, because Mr. Steam with his strength of magnitude sweeps away the beautiful 1000 BTU heat with a mere 1 pound embrace. Ohh, I would melt too. 1000 to 1. Try putting that into a meaningful percentage rate, we're not talking peanuts anymore.

If steam has the disadvantage of operating at a minimally higher boiler temperature it more than overcompensates by working one thousand times harder. I think the trade is a no brainer.

Air carries heat around at roughly the same load factor as water, on the order of one BTU per pound, you'll find a pound of air packaged into several cubic feet. It takes work to manage this large volume, but with a large delta T, it is doable. The comparison between steam and now air is, again, a no brainer.

How do boiler manufacturers compensate for this excessive laziness on the part of working hot water? They multiply the area of the boiler heat exchange surface (the boiler is added the condensing coil which is full of crumpled up surface) Now, water is accommodated for its slow pace. Still, 1000 to 1, you've got to figure out how to put a lot of crumples; and this does not make the boiler either cheaper to buy or easier to maintain. Something to consider deeply in an age where cost is almighty.

Isn't it amazing how we'll rush ourselves in order to provide for the under-performer while at the same time we'll ignore or worse give much contempt for the overachiever? Government agencies, regulatory bodies, inspection departments, taxing divisions have this in their mission statement, it seems energy efficiencies commissions follow the same track.

Let's clamor for the HeLoTHiRE?! rating - Heat Load Transport Hitherwards Ratio Efficiency number. Helloooo?

Let's give a big pat on the back of our steam boilers. Imagine how much more productivity and efficiency we could squeeze from steam systems if we adapted them with the same additional condensing coil we give to the undeserving hot water boiler.

It's not the only bail out we've provided to hot water. Modern systems need fancy electronic controls without which they would recklessly overheat our homes. This indoor overheating is the source of inefficiencies and waste that can be so large you'd wonder why you were giving your flue the evil eye. Same thing about thermostatic valves. Boy, there is money in gadgetry.

It's like the Olympic games, the athletes pour enormous and continuous effort into achieving optimal performance, which by their standard is measured in nose length at the finish line. It earns them the gold medal, sure, but for my case, an athlete who's only got very vague memories of gym class, the dream of ever sustaining those levels of performance is a complete joke. Heck, it's only February and the New Year workout resolution is already long abandoned.

In many ways I think a simple and robust system has a lot of merit just on its own, because it can easily be sustained. We don't all have the discipline of the no. 1 guy, and we don't all want to rely on performance boosting (vitamins?).

Here are the winners:

Bronze: Modern hot water hydronic is terrific

Silver: Old fashioned but top shaped steam is a nose ahead

Gold: Modernly outfitted steam just busted the world record for the next thousand years

I hope I earned a chocolate medal for this one.

Yours truly

Dean_7

steam

Interesting discussion. Lets see now It has been two full years since I restored my steam heating system. Tracking fuel usage over these two years has indicated a 47% overall average reduction in natural gas used with a corresponding decrease in costs. This has largely offset the increased natural gas cost this year. Last month the gas bill showed a 13.9% decrease over the same time last year. There is one thing different this winter over last winter. I listened to Steamhead and Maddog an installed a vaporstat. This whole system runs on 6oz of pressure ( I also installed more accurate gauges). The natural gas bill for Feb. 2006 was $72.00.
And I live in northern lower Michigan just off the Lake Michigan shoreline so it gets cold here. Therefore all in all I think steam heat is pretty efficient if done right. Thanks Steamhead and Maddog.

[Deleted User]

Christian...

Your passion for steam is obvious. The story you purvey is cute, not real true, but cute.

Sometimes, if you believe hard enough, you WILL beleive it to be true.

Bottom line, efficiency of one system to the next is not based solely on the heat source. As for analogies, I can have the worlds most powerful engine in a car, but if the transmission slips, or if the tires are bald, I can sit at the intersection smoking the tires off the car, making a big impression on anyone standing near by, but the energy efficiency, that point where the rubber meets the road SUCKS. And in MOST steam systems, that is the case. Excellent generator of energy, TERRIBLE purveyor of heat.

If steam, and steam systems were as efficient as you make them out to be, why have they not been used in foreign lands where the cost of energy are so much higher? Why are they not the main system of choice here in the good ol' US of A?

Having read about every one of your posts, your bias towards steam is quite obvious. And bottom line, there are a lot of steam systems still out there chugging along, and those systems need people like you, Frank Wilsey, Gerry Gill and all of the other masters of the TLAOSH to carry on. But on a practical, reasonable level, a properly designed, properly installed, properly maintained hydronic heating systems trumps all.

Bottom line, tell me this. When we as a world are forced to go to alternative energies, like solar thermal and solar electric, how easy is it going to be to interface these mandatory systems into your steam buggy?

Your passion is appreciated. You need to get some new updated energy glasses though... Look into the future. Do you really see any steam systems out there? I don't.

Suncerely,

ME

Jerry_15

STEAM EFFICIENCY

I couldn't agree more with Mark. It's all very nice to get these old originals working to peak efficiency, including a shiny new boiler, I do it all the time, but to compare it to Hydronic on a new installation on a single family residence is ludicrous. Does anyone even make a 95% low-pressure steam boiler, Gasmaster has one size, 1 mil k. A bit large for most I think. In Europe they do it with high pressure district heating, knock down the pressure at the house, and bill by the condensate return with a meter, they also have some pre-insulated pipe on a roll, and good public transportation, and health care, etc. Yes they pay 5$ a gallon for gas, all taxes, but at least it comes back in public services. The price of ng out here just went up over 50%, all profit, no return. The people that I work for are mostly pretty well-heeled, and they're cryin. But some that I see ain't so well off, and are in an absolute panic, and it's not even cold out here!! Of course it's possible to design in radiant take off's, I've done it very successfully, and DHW too, heck, submerged coils have been around for a long time but do you really want to keep a cast iron boiler cooking all year for DHW? For the difference in the cost of installation alone, leaving aside energy savings on a 95% boiler, and energy star, local energy credits, etc., you could put in a nice little gen set, cause none of it works when the power's out. Oh, scuse me, I'm sure someone must still sell standing pilot millivolt boilers out by you. They've been illegal here for 15 maybe 20 years now. Sometimes you have to temper justice with mercy.

Jerry_15

No, actually people are not more wealthy now, but there are more wealthy people. When steam was king the alternative was a fireplace, and only very wealthy people could afford it, and the price was spectacular then, and now. They also had no other options. As soon as two-pipe steam came along, one pipe was dead. Gravity hot water, you bet, forced hot water, smaller pipe, absolutely, radiant floor? Do you really think that some rich guy years ago would have had 15 guys threading a trainload of iron pipe for weeks if there was an option? Rich folks mostly didn't get that way by being dumb. There are, of course, exceptions to every rule.

adayton_2

Mark and Jerry

have obvious enthusiasm rightfully so regarding Hydronics heating medium. However, how about applying the same modern efficiency engineering design factors to a steam system. I would bet that THEN the BTUs/Therms IN -VS- heat value transferred usefully out to the house would be almost indistinguishably VERY close. The only difference then being the ability of steam to provide almost instantaneous massive horsepower and its "resistance" to freeze ups....

Alfred

Jerry_15

Let me think about this: Instananeous massive horespower vs modulating 95% boiler tied into outside/inside temp and adjusting automatically to anticipate rapid outdoor fluctuations for constant even indoor heat without overshooting. On the Prestige it all comes with, with built in up-front control panel. Don't even need a mixing valve. Tough call. On commercial, makes some sense, but what do you about the traps and domestic water on a big freeze up? Better not to go there. At least you can glycol a hydronic, it would be the only man left standing it a real disaster.

Jerry_15

PS

Oh yeah, and I don't need four guys and a fork-lift to put it in. My back brace lives in the shop now. Tough call, tough call.

Tony Conner

There...

... is more than one way to calculate "efficiency". The long accepted method for calculating steam boiler eff is:

net heat out / divided by the heat input of the fuel X 100

It's a nice simple straight forward calcuations that captures ALL of the loses.

Check out the method for calulating the AFUE eff. I realize manufacturers are required to use it, but to me, it's an engineering calculation method devised by the marketing department. And there's no need of it.

Tony Conner

There...

... is more than one way to calculate "efficiency". The long accepted method for calculating steam boiler eff is:

net heat out / divided by the heat input of the fuel X 100

It's a nice simple straight forward calcuations that captures ALL of the loses.

Check out the method for calulating the AFUE eff. I realize manufacturers are required to use it, but to me, it's an engineering calculation method devised by the marketing department. Use the boring old heat out/divided by heat in formula for the hot water units, THEN make the comparison with steam. Hot water will be more efficienct because the flue gas temps can be lower - but the eff difference will not be nearly what a lot of people imagine that it is.

Boilerpro_3

Some thing doesn't seeem right here

Most of the very wealthy,no matter when, lived in very large homes. Steam heat is found in some of the smallest homes and rowhouses throughout the US.....Not the homes of just the wealthy. A small 1400 sq ft home on a 20 foot lot or a 2 flat of which there are tens of thousands in northern cities never has been the typical home of the wealthy. Alternatives besides fireplaces were also available, gravity hot water, gravity air, and in the 20th century, forced air and forced hot water.

Boilerpro

Steamhead (in transit)

Mark, I have read

that it is possible to generate steam from solar energy. The article is around here somewhere, when I find it I'll scan it for the Library.

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Steamhead (in transit)

Jerry, you're used to seeing

systems designed by old rule-of-thumb methods. When you design a steam system using a modern heat-loss calc, as several of us have done, everything is noticeably smaller. I doubt you'd need your back brace for something like this.

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Boilerpro_3

Alternatives

A top notch two pipe vapor system does not need traps, or at least very few, so freeze ups are not a serious issue.
As stated previously, this same high quality vapor system can also have outdoor reset, with modulating pressure. They were doing this nearly one hundred years ago. In fact nearly every steam system runs on outdoor reset by the inherent nature of the mass of the radiators. Overheating indicates poor control, just like any other system.
I do agree with you on the weight issue, but modulars make this a lot easier. Prestiges are a lot lighter.

Boilerpro

[Deleted User]

Frank...

I have worked on solar steam generating systems. The problem is storage and handling. It's not a matter of whether is can be done. Its a matter of whether its the right thing to do or not.

As for system efficiency, I have no doubt that a new, properly designed 2 pipe steam system as designed, installed, maintained and controlled by you would be extremely efficient. Probably even more efficient than SOME hot water based systems out there.

But I guarantee you that if you and I had identical new homes to heat, and you went the steam route and I went the radiant, modulating/condensing route, I'd use at least 30 percent less energy than you, and solar interface would be a snap with mine. It's just the basic thermodynamics at play here. No smoke and mirrors. You know this to be true...

Respectfully,

ME

PS, Welcome back from the land of Timmie. I'd LOVE to get out there some day and listen to the man teach.

ME

Steamhead (in transit)

I agree solar is a great concept

but as practiced today, can it work in an urban environment? How much collector area is needed to heat the typical rowhouse? How much for a larger house? How much less efficient are the collectors when they cannot face due south?

If you have room for a large collector array, I would think it possible to arrange a moveable mirror to focus the sun's heat onto it. You may have worked with these, I'd be interested to hear about your experiences. There was a device called the Heliostat that used this same principle to light office buildings. There wouldn't be room to put such a thing on the typical city house. But a centralized collector system that could feed a large area should be able to incorporate this without much difficulty.

Many cities have (or had) district steam systems whose original purpose was to eliminate the need for coal-fired boilers in every building- one of the first efforts to reduce air pollution. Since many of these systems are still operating- some now burning garbage to create steam- applying solar to them would appear to be a good fit.

What say ye?

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Christian Egli_2

What would Dr Evil do?

Vindication will come when all hydronic systems will have been replaced by combined AC / hot air heat pump systems. Europe is embracing multi split ductless AC / heat pump units, Asia is all about split systems. Our own southern states need nothing more than AC / heat pump units.

Why do I seem smug? Because heat pumps are vapor cycle jobs just like steam. The world will have (efficient) vapor heating after all. The efficient energy transport mode.

Geothermal systems are, roughly speaking, a combination of (delayed) solar gain and a vapor heating cycle.

Funny no? The guys who heckle us at the exit of the Home Depot stores (in my part of the country at least) may have it all right after all - don't they always propose to rip out the beloved radiant systems and exchange them for a hot air furnace and a quick fix ducting job? They even argue the salvage value of the cast iron will pay for the sheet metal.

To, me that's admitting the old stuff has value indeed. Count on the fact no one will want salvage sheet metal. What's the salvage value of your comfort, oh, just your soul and a contract signed in blood.

Go radiant heat, go water, go steam, go gas fired tube, we're all on the same boat.

But perhaps I should never be made an Olympic judge. Biased? me?

Let me know of any gross untruth about my statements, I think I am usually very careful with loose facts.

Just give me one meeelion BTU and you'll get your thousand pounds of vapor. Fun, 1000 to 1, guaranteed.

ttekushan_2

steam efficiency

Some interesting points here. I'll mention right now that I am biased towards steam heating. Do you think for one minute that I was genetically predisposed to a steam heat bias? I grew up with forced air, and live with it now. I know well its limitations. A good portion of my young life was spent in a grandparent's large home with gravity hot water. My exposure to steam was in public buildings and schools. Steam was so impressive to me because it could pick up room temps so astoundingly quickly. But the gravity hot water system was so even and, well, radiant. The gas bills at grandma's hot water heated house were twice ours. But her house was 3 times the square footage. Taller ceilings. No insulation (ours was insulated). Granny hated to wear sweaters so she kept the 'stat at 74 degrees. We were at 68. The boiler was the original 1901 natural gas sectional, not converted. I was always impressed by that. I thought, "Hmmm. The ancients seems to have been on to something..."

All of my other exposures to hot water have been the typical pumped arrangements with CI boilers. The heating costs in every one of these set ups have been notoriously high. As I worked my way into this business, I've never been able to give customers great improvement by doing diligent maintenance on these systems.

This is why I could never understand the veiled hostility towards the antiquity of the gravity hot water set up that I see from time to time on this site.

Then came my rental of a commercial space with two pipe steam heat. I was stunned by the ability of steam heat to equalize the temperature of the store front spaces to the residential spaces, even though there were NO zone valves. Open the front door, radiator condenses more steam than the warmer space next door. Simple and brilliantly effective. But the system was an energy pig. So I adopted it with the landlord's blessing. This was many years ago and over time I was able to tune that system and bring fuel consumption down about 45%. Excellent balance, comfort and economy in the draftiest, loosest building I have ever seen (snow drifts INSIDE the windows and doors). This changed everything for me.

Yogi Berra once said, you can observe a lot just by watching. Every heating system I've seen I looked at within the context of the enclosing structure and the era in which it was installed. The more I looked the more I was impressed by the fact that steam systems were usually neglected but still funtioned. Impressed by the results of boiler descaling and water treatment. Impressed by the results of improving the venting strategy. And impressed with the fact that the steam heating's great comfort often conceals horrible insulation and weatherization. Unfortunately the steam heating era coincides with the horrible insulation era so the former is often blamed for the latter.

So it seems that the popular hot water conversion is merely a means of downsizing the system. Can this work? Yes. But more often than not a steam system in failure mode is the standard against which the hot water system is judged. OF COURSE its going to be better. Optimized steam is a different story. But we all know that. Or do we?

Lets see. So one person is accused of being biased towards steam. So his and my observations are not correct. Apparently a pro-steam bias is the only one that can exist. Yea, yea, the numbers this, the other numbers that. In order to make efficiency numbers easy for the consumer to understand, the whole analysis of system efficiencies becomes so ridiculously oversimplified that the numbers are rendered meaningless in all but the grossest terms. Gads. the audio electronic business is exactly the same way. The standard measures are always taken with the component under test out of its application, and no attempt is made to determine how its performance changes when applied within the system in which it is necessarily going to operate. I see its the same in heating. Wonderful. But I digress.

So in a previous thread I suggested a small scale economizer for residential steam boilers and I was told it would probaby make little difference on a small scale. Then why does a condensing boiler work on a small scale?

So my contentions are these:

-Steam as a heating medium is outstanding, especially considering the heat is contained in such a light medium. Reticulation costs are extraordinarily low.

-Circulated hot water can outperform steam only if condensing boilers and sophisticated electronic controls and high efficiency pumps are employed. You can be the judge of whether the extraordinary first cost of these systems are economical. Also remember that any failures are commensurately expensive to repair.

-No one installs steam anymore for the same reason no has installed gravity hot water for years. Has anyone priced US made 3" steel pipe and fittings recently? Not only that, piping these systems is a large and expensive art that is not required when you can merely force the issue with pumps through small lines.

-Economizers applied to steam boilers have a proven track record of saving energy. Their cost is not so prohibitive that the payback period is fictional. I priced one for a 150 HP boiler connected to a 4500000 btu heating system. About $15,000 installed. It effectively takes the boiler from 83.5% efficency to 94%.

-Economized steam will outperform even the best mod/con/etc water systems or I'll eat my hat.*

So I feel a bit odd having to defend steam heating on a site like this. My revelations about steam heating came from direct experience with the various heating set ups in virtually equivalent structures. I think all the steam people here have had similar experiences. I know I was impressed at how the average steam heating system responds to some TLC. The hostility towards steam heat I am seeing here is both amazing and disturbing.

-Terry

*My hat's made of chocolate.

adayton_2

Instananeous massive horespower

Yes Jerry, horsepower produced by those self-same very high efficiency mod-con (whatever....) units that are employed in radiant heat. I do not believe that some kind of "dual firing unit" (if you will) one HALF lower temp for the radiant (or hydronic baseboard) the other HALF (or two third/one third proportionate) using mod-con and stack heat-reclaiming device (economizers and what not) would not be extremely close in efficiency and of course utilize the same set-back and other modern sophisticated system control modules. The benefits are YOUR SAME low temp type efficiencies and comfort combined YES with the horsepower ability of steam to quickly ramp up large spikes in heat needs that DO IN FACT arise from time to time as spikes in cold fronts or usage pattern spikes. Obviously should weather patterns happen to be smooth/average/tepid (like most of this winter) then the steam portion would remain idle. You would of course enjoy the well deserved comfort and reliability of steam besides the perhaps minimal benefit of "horsepower"..

Speaking of "reliability" lol.. :-) Has anyone ever done reliability/maintainability/serviceability/MTTR/uptime models on NEW systems -VS- Original Old Steam systems??

ROFLMAO....!!

Just food for thought

Alfred

Jerry_15

Darn tootin they're lighter, and smarter, and prettier: unlike us. When you can find a 250k input, 95% AFUE, steam boiler that I can carry in with another guy in a cardboard box and hang on the wall, let's talk. Till then it's just lipstick on a...well, you know.

Jerry_15

I find it somewhat poignant that horsepower would be used to add a couple of extra decimal points to simple equation, and that's all it does. BTU's, Watts, Horsepower, it's all interchangeable; and easily calculable. The conversion charts are in the back of your dictionary The distance to yourlocal convenience store is 1 mile. In light years that is (sic) >0000000000000000000000000001
On a big commercial system you use horsepower to save ink on the zero's. On a house, tell me please, what is the horsepower on a 80,000 btu boiler?

Jerry_15

In those days they were considered wealthy, not rich, just well off and secure. Middle class I think they call it now.

Jerry_15

But can you hang it on the wall? Sure, I calc the demand and wind up putting in a boiler a 1/4 of the size and 1/2 the input, but I'm still waitin to hear which brand you recommend that can do that for steam. And how do you get the old one out? Beam me up Scotty, beam me up.

Jerry_15

Many good points, and no, I don't plan on putting in any steam systems, or gravity systems, in the near future, but I did just convert a 100 year old gravity system to a Prestige, with domestic, and was able to add a couple of rads down low which would never have worked without the circ. pump. Works like a charm. Cast iron rads throughout. It doesn't need the big heat of steam, or the wait on the fire up. (course it is in Oakland) The gentle heat on the rads seems to be ok, in fact desirable: I've had to turn down the temp on the heating side, at owners request. Bushed the main distribution 1 1/2 black iron manifolds right down to 1" pex which I used off the boiler, and branched down as needed. No problemo. Add rads, anytime. DHW on 1" take-off, workin perf. At 94 % pretty hard to beat. So, got a better idea?

ttekushan_2

gravity, control, water, steam, comfort, ecology, and all that

I'm not nearly as unreasonable as you might think.
Really, I don't think the wetheads (I thought maybe "water boys" but that reeeeally sounded offensive) and the steam guys are quite as far apart as it may first appear on heating technology. I like heating that is even and has a high radiant component. Isn't that the way the home loses its heat? Well, this is the best way to replace it, no?

Until more recently gravity boiler updates were pretty much "cram a pump on it, that's good enough..." sort of an approach. Ahhh, it always seems to come down to execution.
What you have done by availing yourself of the freedoms that advancing boiler and controls technologies provide sounds pretty darn good to me. Anyone with standing CI radiation has to consider the kind of job you've done. The radiant component is the first and last thing out of those big radiators. Even our northern climates have substantial parts of the year with mild temperatures. As I said above, "radiant" is how it feels.

But there are so many things going on thermodynamically with steam as a distribution medium that continue to bring me back to it.

Just because an economizer on a steamer doesn't look or work like a condensing boiler doesn't mean the end results can't start to look startlingly similar. All evidence points to the fact that we have to spot steam a few points beyond boiler efficiency ratings due to its ease of distribution. Distribution doesn't come free, and specific heat per unit of medium moved can tell you a lot. Can we at least agree that forced air is the lowest performer in this regard? Now. Steam would have to be the winner in this regard, but... Is that enough to offset the big advances in hot water boiler and system designs?

THIS is where the real disagreements originate, I think.

There's never any discussion here like, "Ha! My preference is cheap and easy!" Or, "Ha! My preference is inferior but I laugh all the way to the bank!" None of us here bow to the altar of lowest first cost, nor the quick and dirty. We all get off on getting excellence out of "top shelf" heating systems. And I dare say that we all like comfort in the most guilt-free manner possible (I'm referring to temperature and ecology kinda things here). Are we really far apart?

It just annoys me that there doesn't seem to be any logical reason for steam technology to be artificially stuck at 100 year old levels. Although it does astoundingly well, we can do better. I liken it to the automotive era where engine management systems began to sharply increase the efficiency of gasoline powered vehicles. Many suggested that that was the end of the Diesel, with its belching smoke and low power. It never occured to anyone at the time that the same advancements applied to the Diesel would move it similarly forward in power, cleanliness and efficiency. The Europeans were the ones who saw to it, at that.

I can visualize advanced mini-district heating systems in moderately sized buildings with steam as the primary distribution system. Where height and distance are concerned, steam doesn't care much. Steam has tremendous strenghts in distribution. Water's great strength is control of space temps, and low-temp long-duration heating. Excellent for radiant, and seasonal efficiency. Residential (I mean for us mortals residential scale) would not justify the transition from one medium to another. Make up air heating for higher occupancy areas could be derived directly off the steam (allowing of course, for the protection of traps from freezing). I see no philisophical reason, or practical one for that matter, not to use the strengths of each heating medium.

Furthermore, I am not content to say, "The Europeans don't use steam this way, so neither should we." Are Europeans infallible in their measures of system efficiencies? Every new design, be it break-through or evolutionary started out as a design problem. There's an old addage, "If no one cares to solve a problem for a long enough time, it becomes 'That's just the way it is.'" I refuse to accept that premise in any area of technology that has merit.

So will I have to eat my hat? Its too early to tell. Will I have to design something myself? Probably so. But just in case, Anyone know how long chocolate keeps?

-terry