80 to 90% efficiency $$ savings?

jp_2

right joannie,

the boiler is in fact modulating the temperature, you just see it as constant, but if you 'looked' from the return side, you'd see it as varing.

remember, a boiler is a water heater, it heats water.

Dmitri_2

test

test

ttekushan_3

Check it out, Steamhead

> unless you know what condition the old steam

> systems were in. Given that these systems were in

> schools, it is reasonable to assume until proven

> otherwise that they were in terrible shape from

> neglect and poor maintenance. I've said this

> before and I'll say it again, comparing a steam

> system that has been abused and knuckleheaded to

> a new hot-water system is not, has never been and

> will never be a fair comparison.

>

> It would be

> very interesting to see how poorly the new

> condensing boilers work after a few years of the

> neglect they will suffer in these buildings.

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 367&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

ttekushan_3

Check it out, Steamhead

I don't want to offend the sensibilities of anyone at this thread, so check out the Church Steam Savings.

Enjoy!

-Terry

ALH_4

semantics

I have to disagree. The burner is modulating the heat input rate, not the temperature. The heat input is modulated based more on the heat loss than on the desired supply temperature. The reason I view it this way is because the burner could be anywhere in its modulation range for any given temperature. This means the two are, for the most part, independent of one another though higher firing rates should tend to coincide with higher supply temperatures based on the characteristics of the heating curve.

Both temperature and firing rate depend on heat loss, but firing rate does not depend on temperature.

jp_2

andrew,

maybe you misunderstand me? I in no way am saying that modulation and temp are directly proportional. I'm not saying that 50% mod = 155F supply temp.

but isn't the easiest way to monitor and control 'heat' by viewing temperature? as far as I can see, thats all the controls do, they look at temperature, not 'heat' or heatloss.

also, the boiler is varing temperture by modulating the burner, or in the vito the pump speed too, what else could it be doing other than varing temp? to my understanding no boilers out there monitor GPM.

Uni R_2

Easiest way? RPMs?

Wouldn't the boiler's fan speed be the easiest way to accurately "monitor" the heat being applied by a modulating boiler? The RPM correlates pretty well perfectly with how much heat is being applied to the water.

ALH_4

jp

I think we agree, and I believe I did misunderstand your point.

All I am saying is that the firing rate is independent of supply temperature. The burner does fire to maintain the correct supply temperature through some algorithms I am not entirely sure of that seem to vary somewhat depending on the manufacturer. It seems like the rate of supply water temperature change as well as the distance from the desired supply temperature would be taken into account.

As you said, a higher firing rate does not necessarily mean a higher temperature. That was what I was trying to clarify.

jp_2

andrew,

i figured sooner or later we'd agree...

sometmes its easy to read something too fast, or while thinking about something else.

Chris_82

Steamhead...the voice of reason,

On target, Steam head your point was in that report only it was disguised in engineer speak. What is interesting is that no one is quoting the 60 percent and "suspect larger" value for the increased costs for the mod/cons., never mind the special waste costs for the concrete eating condensates. And again my main point: until the manufacturers manufacture a quality product, we are debating a moot point guided and steered by the marketing departments of an industry that has a profit motive at heart, driven by hysterias of rising fuel costs, which they take full advantage of. And until they have a financial interest, think legislation, which is frequently ignored in our comparisons with other countries, these manufacturers are free to run all over us "Jake and Jane, six pack types."

Dr Pepper

Your all almost there, but...

nobody asked about the WHOLE SYSTEM... if it is baseboard designed to run at 180*-200*F your condensing boiler is still running at 180+ on design days. The building system needs to be looked at and designed to run at 120*130*F (double the active elements maybe???) and let the condensing begin. All you can expect is to stop letting the heat go up the flue, so if you can improve the design days then you really have something. I think even the hydronic manufacturers haven't done enough thinking about this subject, show me a chart for baseboard that shows heat output/ft with 100* water?? IMHO LOL

John Ketterman

> maybe you misunderstand me? I in no way am

> saying that modulation and temp are directly

> proportional.


Actually you did. What you said is that "The two [modulation and temperature] are the same". That's what I objected to. They are not the same.

Uni R_2

It's not a simple comparison...

I have a 180F designed baseboard system. Like you, I doubt that my new modcon will condense at 0F. Anything above that, and the return temps should actually be in condensing range.

So for 2 days out of 200, should I completely redo my whole system so that my efficency doesn't drop on a design day? As much as I'd like to have panels and TRVs instead, I'm not sure that it is necessary or cost effective.

Steady 106-118F baseboards (when heating) have been the norm so far since retiring the old guy but outside temps haven't dipped much under the freezing mark so far.

John Ketterman

But the savings numbers (avg 49%) you are quoting are from Table 2.

Table 2 numbers are not adjusted for degree-days!

ALH_4

i think we all agree now

jp did say "the way the boiler lowers its temp is through modulation, so the two are the same, not different as you are eluding to."

You correctly pointed out that this statement is incorrect because a fixed fire boiler can also run at any temperature.

However, at this point, I think we are all in agreement that modulation does not correspond directly to supply temperature. Heat and temperature are confused too often.

jp_2

maybe then I still am correct

i ask then, what does modulation do if it does not control temperature? i think in the sense of mod/com boilers, mod=temp variance. i agree i probably did not word the orginal statement prefectly.

edit: as i said before, the vito has one temp sensor, thats the only feedback it has, therefore there IS proportionality between mod & temp, just not a one to one as 50% = 145F or something.

andrew i understand the temp/heat thing but we are talking about a closed system, one variable, temperature.

Mike T., Swampeast MO

Correct in that boilers generally do modulate to achieve some temperature somewhere in the system, but incorrect in believing that there is a direct relationship between modulation level and temperature. The direct relationship occurs between modulation level and system load. Note that I did NOT say "between modulation level and heat loss". To achieve that reasonably you really need TRVs and most certainly need boiler controlled variable speed primary circulation with any form of primary/secondary.

A Vitodens directly (no LLH) driving a TRVd system with load above minimum modulation will fully and by reasonable standard perfectly modulate to achieve any desired supply temperature as long as such temperature is at least sufficient to meet the load. However, the higher the temperature is above what is truly required, the less efficiency you get from the boiler. This is why mod-cons usually use some form of reset--they want to modulate to the load at the most efficient temperature...

jp_2

then what?

moved down to COPY

jp_2

copy

"""incorrect in believing that there is a direct relationship between modulation level and temperature."""

as i said, the ONLY sensor is a temp sensor. this has nothing to do with load. theres no means your vito can measure "load" only supply temp, only supply temp......

mike you just said what i did:

"""..... perfectly modulate to achieve any desired supply temperature.............. """""

"""incorrect in believing that there is a direct relationship between modulation level and temperature."""

seems to me these are contradicting stements????

some control tells the boiler a set point temp, the boiler modulates the burner to keep 'close' to this set point.

ALH_4

yes

I am positive we all agree. I was confused by your first post about this topic as I think others may have been, but you have clarified it and I think we agree completely. We have the opposite of agreeing to disagree here. We have disagreement about our agreement. hahaha

I have followed your posts in other threads, and feel we're of a like mind on many things. I look forward to future discussion, but for now I am bowing out of this one since we agree. lol

Modulating boilers use temperature to determine their firing rate.

GW

Doc

you rule man; I get a chuckle out of all these comments. If this guy has a cheesy baseboard system, i DOUBT the new boiler will shine at some of the wild guesses I'm seeing. Was the system even mentioned? That shows how much effort goes into some of these responses!

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

jp_2

yep, i agree

i agree too. I think we had this discussion awhile back.
fun discussion.

John Ketterman

> """incorrect in believing that there is

> a direct relationship between modulation level

> and temperature."""

>

> seems to me these are

> contradicting stements????


Here we go again. Those are not contradictory statements!

You use the accelerator in your car to reach your desired speed, but that does not mean that there is a simple relationship between how much you are depressing the accelerator now and your current speed. That's because there are other factors at play, such as whether you are starting from a stop, whether you are going uphill, etc.

> some control tells the boiler a set point temp,

> the boiler modulates the burner to keep 'close'

> to this set point.


The boiler modulation VARIES even if the set point does not. I thought this thread has covered this about five times.

(I will quit posting to this thread now.)

Leo G_99

R,

think goethermal. The larger the structure, i.e., schools, hospitals, etc, the more "efficient" geo becomes.

Leo G

Dave_4

> you rule man; I get a chuckle out of all these

> comments. If this guy has a cheesy baseboard

> system, i DOUBT the new boiler will shine at some

> of the wild guesses I'm seeing. Was the system

> even mentioned? That shows how much effort goes

> into some of these responses!

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 368&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

Dave_4

Hey Gary

The original poster stated that he has standing iron. On the other hand, I have "cheesy" baseboards. So as a Pro, do you feel I wasted my money on a modcon?

GW

may I

May I be excused from this debate? My apologies to anyone I may have offended.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mike T., Swampeast MO

Sometimes I think your only understanding of heating control comes from a simple free-standing solid fuel stove.

"Perfect" modulation can occur at any temperature sufficient to meet the load. Add more energy than required to meet the load and the temperature will rise.

scott w.

CI boiler to mod con usage

In Nov. 2004 changed out a hot water 300K btu W/M CI boiler to an Ultra 230. Did see significant dollar savings in gas bills due to the very large increase in gas cost due to utility company increases. Did tighten the envelope.

November 2003; replaced twenty five single pane steel casement windows that leaked like a seive. Added some additional blown in insulation in a few places.

Put radiant floor(gyp)in kitchen Nov. 2004 that had no rads.Was heated by

Mike E_2

Slant/Fin does give a correction chart

On Slant/Fin's new website, the ratings chart has a statement over the 110-140 degree colums saying "Ratings for Condensing Boilers coming soon"

I had, however, found an Engineering Data sheet a few months ago on their site (can't find link to it now though). They provide a chart that gives correction factors for water temperatures and air temperatures other than standard.

You have to take the rating for 215 degrees and multiply it by the correction factor.
Here is the columm for 65 degree entering air.

90 - .08

100 - .13

110 - .19

120 - .25

130 - .31

140 - .38

150 - .45

So for Fine/Line 30, the numbers are as follows

90 - 69 BTU

100 - 112 BTU

110 - 163 BTU

120 - 215 BTU

130 - 267 BTU

140 - 327 BTU

150 - 387 BTU

My house which has baseboard installed in the 60's, only needs 145 degree water at -4 design condition. On a 32 degree day it can run at 110.

jp_2

sometimes

I think you're in a dream world of make beleive, and an article from popular science......did you forget to take your medication again? once again you're way off mark!!!!