High efficiency boilers

Mike T., Swampeast MO

Super-Simplistic Fuel Reduction Calculation

From January 6 through February 3 of this year, the mean temperature was 30°.

House looses 44,218 btu/hr @ 30°. 696 hours this 29 day period so total loss is 30,624,000 btu.

Energy used was about 650 therms for the boiler. 100,000 btus/therm make 65,000,000 btu consumed.

Another simplistic calculation with degree days. 1,013 degree days during this period. House looses approximately 1,141 btus each hour of a degree day or 27,384 btu/hr/°/day.
Times 1,013 degree days is 27,739,992 btus required during the period.

Using the larger loss by mean temperature, that means my system as a whole was 47% efficient in its use of the energy in the fuel.

The WORST case scenario for the Vitodens is the I=B=R SYSTEM efficiency rating of 70,000 btu/hr with input of 91,000 input or 77%.

During the same period at 77% efficiency I would have used 39,771,000 btus or 391 therms. This equates to 40% less fuel.

I know this is horridly simplified, but I tried to calculate in the best case for the existing system and worst case for the replacement. I know that 50% savings number that floats around with some condensing boilers on a gravity conversion system is fantastic, but it honestly seems achievable.

Kal Row

i wish Tim McElwain would do a combustion...

analisys and report on the vitodens, ultra, and muntchkin

i would be very supprised if the vitodens did not come out on top

rb_5

great aim at a questionable target

Unknown

Kal, if someone has one of each

near me I will do that. Now I am curious. Anyone want to set it up???? Let me know.

I could do one test at HTP in Freetown and the Viesmann folks are just up the road from me.

Dave Walsh my good buddy at Weil McLain may be able to set me up with an Ultra.

Let us see what happens.

rb_5

Inefficently delivering efficiency

Others have done a better job than I could to answer the question directly...but I do throw out a thought and a question for the topic...

Great aim - questionable target?

We often focus on the combustion efficiency of equipment and rarely if ever discuss the inefficiencies in mining the raw ore to eventually taking the product to the dump or recycler. Always wondered what would happen to the lifetime value of something sold based on combustion efficiency if we considered the lifetime capital and environmental cost of electricity, diesel fuels, and several other gases and materials to give birth to the product, have it delivered from where ever in the world including all the fuel burned up going back and forth to the project not just during the installation but follow up calls for repair and maintainance then ultimately the fuel burnt up to discard or recycle the product.

Just curious but has anyone heard of any manufacturer from any industry selling their product as the most efficient alpha to omega to create, operate and destroy?

hr

And the cost of shipping energy

As the price of crude continues to rise so does the cost of shipping it.

China has passed Japan as the second largest importer of oil, after the US.

Shipping a load of coal, for example, from Australia to Japan cost @ $20,000 a day last year. Currently the price is $50,000 per day!

Lack of freighters and tankers will cause the prices to climb more as countries like China develop appetites for oil, coal and natural gas. According to an article in Solar Today mag this month.

Concrete and steel is flowing to China big time also. JLC reports concrete shortages in the southern states as shippers and actual shipping routes have been modified to divert more materials to a hungry China.

With 1.3 billion people, China will soon catch up and pass the US for energy needs. Opec may some day tell the US of A to take a hike as they have bigger fish to fry?? It's quite possible China could consume the entire OPEC production in the near future.

Fuel for thought.

hot rod

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Mark Eatherton1

Why not...

give them the test parameters you want to see it operate at, and check them thermally. BTU in Vs BTU out. Basic thermal efficiency. Give them four different load factors and see what they do. Forget about AFUE and all the other stuff. Just basic thermal eficiencies. I know I saw a verifiable 98% plus efficiency on my system. And I was no where near design conditions...

Who would verify this information? ANSI, ANSY or Antsie or Auntsie or Auntsy??? Worse yet, Nancy from ANSI...

I'd sure like to see a comparision. I predict they'd be within tenths of a point from each other. They're all the same basic technology with each companies personal bent on the situation...

I could do at least three at my current class at Red Rocks.

I already have a Munchkin (EARLY model), a MZ (My FIRST condensing boiler, Thanks Pete!) a Slantfin (Thanks Greg Gibbs et al) numerous other cast iron boilers (properly aged and tenderly handled...). We just got extra storage space.

It could be done!!

ME


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Kal Row

i will be tricky though...

cause you have to test combustion in the chamber and at the flue outlet - getting into the chamber in these usually means drilling a hole somewhere, where to drill, as to not affect it, or worse, break it, is tough

then, there is the heat transfer test, - you need precise measurements of flow volume and Delta-T

Measurements as to how different return temps affect combustion – might need a serious thermo imager

at the end we want to know, at different temps,
1) who is turning the least amount of fuel into the most btu’s,
2) who can deliver the fastest punch as in shortest ”time to heat”,
3) whose performance is best overall

setting it up really needs a serous lab – that’s why our trade mags don’t do comparisons like the car or computer mags do – a scientific hydronic setup is way to expensive and time consuming – trade advertising dollars wont cover it – maybe we can get the epa to do it

S Ebels

I believe

In Germany, life cycle efficiency from production to the end of the products life is considered for all aspects of construction. Everything from boilers to the structure itself is analyzed in this manner. I caught a few hints at it in Viessmann's Aktuel magazine.

I think most of the world and the U.S. in particular, tends to design for lowest initial cost instead of lowest long term cost. I have felt for most of my life that this is not only wrong but insane. To flagrantly consume raw materials and energy for the sake of cheap production is foolishness of the highest degree.

Our Western society has inverted what is considered a "good" investment is by the use of this philosophy. Think of the millions of new homes that were constructed in the last decade here in the U.S. I would dare bet the the life cycle on most of them will be less than 100-120 years. Maybe less than 80. The technology to build a structure to last for hundreds of years is readily available right now. Why is it not being applied? Because everyone in the loop looks at first cost not life cycle costs.

My gut feeling is that if we in this country don't voluntarily turn our thinking around on this, an economic collapse will do it for us whether we want it or not. After we run out of raw materials is not the time to think about these things.

jerry scharf_2

cradle to cradle

rb,

On the path of a larger scope. Why are you taking it to the dump rather than the recycling plant???

If you haven't come across it yet, you should check out the concept of "cradle to cradle" by William McDonnough. It is a stimulating idea that the results of a product that has reached the end of useful life is that it becomes food or is efficiently reused.

jerry

S Ebels

The problem

Mike, you hit the nail right alongside the head with this statement. "The problem with the Vitodens is that it's not designed for American systems with wall thermostats and multiple pumps".

To hit it squarely on the head it should read like this.

The problem with most American installers is that they don't take the time to understand how the Vitodens is designed to work. They are so locked into stats and pumps that they can't see how simple a hydronic system can really be.

Case and point. This past summer a "Wall lurker" contacted me about a hydronic system for his remodel. He showed me a system using a Vitodens running 5 pumps plus an indirect all controlled with T-87's. This system was "designed" by the Viessmann distributor up in Gaylord MI. THE VIESSMANN DISTRIBUTOR!!!forcryinoutloud!!!!

We just finished the install this past week and needless to say there are only two pumps.

Mike T., Swampeast MO

"Upside the head" not "square in the head".

Once you see the proportional flow you knock yourself upside the head...

Strange thing is that "V" designed a boiler model (the smallest) perfectly tailored to a heat loss table that this "Wall lurker" posted here many years ago...

Bob_37

Okay, can you explain this pump situation in a little more detail for the clueless like myself.

I have four heating zones and have been looking to add a fifth with an indirect hot water tank. I've also been considering the Vitodends as a replacement boiler --- so does that mean my zone system would have to change? Does that add significant complication? Does this apply to other condensing boilers like the Munchkin as well?

Mike T., Swampeast MO

Will try to explain

Realization happened years ago for me when I knocked myself upside the head after staring blankly for hours at a floor to by heated by a "wild" radiant loop off of a constantly circulating system. You probably won't believe this, but for an instant I was the water.

The new breed of boilers with a proportional flame WANT relatively low flow, high delta-t and low temperatures to optimize their efficiency.

The job becomes EXTREMELY easy and the systems HIDEOUSLY SIMPLE if you forget about thermostats and use proportional flow control devices instead of zoning with pumps and/or valves. It's possible without the proportional flow control devices (TRVs, FHVs, etc) but the system must be exceptionally well balanced and a properly controlled variable speed pump must be used as well. (You control the pump via outside temperature by the way. Controlling such via actual flow feedback would be better, but I don't believe this is currently possible at any reasonable price.)

"I've also been considering the Vitodends as a replacement boiler --- so does that mean my zone system would have to change?" You can most likely use the Vitodens on your system and retain the current zoning strategy. Prepare yourself for the possibility of a number of expensive, proprietary components in addition to the boiler. Does this complicate the system? It depends on how you look at it I suppose... BUT, if you forget about the current zoning strategy and use proportional flow control devices, the boiler alone will be virtually "plug and play". The system itself will be MUCH simpler and you'll likely need only need a single circulator without primary/secondary pumping.

"Does this apply to other condensing boilers like the Munchkin as well?"

Probably as those ideals of relatively low flow, high delta-t and low temperature should apply for them equally. BUT, it's all going to depend on the logic used for modulating the burner--as long as it expects this modulating flow and can deal with extremely low flow that will happen with ANY TRVd system there shouldn't be a problem. Obviously, the Vitodens is designed with TRVs in mind as they are required by law in Germany. It is though possible to use a reset ratio that keeps flow quite constant at the expense of a changing system delta-t.

Bob_37

outdoor reset

Okay, so if I'm understanding, the idea is for me to keep my four zones, but get rid of my zone control valves, right? And to do this, I could put TRVs on my radiators. The alternative is to use outdoor reset. The Viessmann guy seemed to think that outdoor reset was the way to go. So can you clarify:

Why is the outdoor reset approach so much harder to "balance"?

Is outdoor reset more costly/harder to maintain than the TRV approach?

How do TRV's work with multiple rooms chained to each other on each zone -- wouldn't a high temp in the first room starve the others?

Thanks again.

Mike T., Swampeast MO

With the Vitodens, you ALWAYS have outdoor reset--it's an essential built-in function of the boiler. Without outdoor reset, I doubt if the burner would be able to modulate (change firing rate).

I can't see your system (obviously) so I have no idea what additional components would be required to install the Vitodens using the current zoning scheme. It may be few, it may be many, but as long as you keep the zone valves and wall thermostats, IMHO you are not using the boiler to its greatest potential of system efficiency.

TRVs turn each radiator into their own "zone". Multiple TRVs have no problem when used on multiple radiators in the same room. There are no more zone valves and no wall thermostats. With the Vitodens YOU tweak the reset curve yourself to achieve YOUR best balance between temperature response, comfort and efficiency. The boiler has built-in setback controls and timer.

As long as yours is a two-pipe system with radiator valves easily accessible, TRV installation is relatively easy. Monoflow systems and recessed radiators can complicate things considerably. TRVs aren't terribly expensive and if you can find someone in your area accustomed to TRV retrofits (and are willing/able to do some of the grunt work) you can keep cost to a minimum.

Once the TRVs are installed, your ENTIRE SYSTEM BECOMES PROPORTIONAL. The burner provides proportional fire to a system with proportional flow and with proportional temperature control in every space. All with a single circulator in many? most? nearly all? cases.

Are your radiators hooked up in two pipe zones? If both radiator connections lead to DIFFERENT main pipes, it's two-pipe. If they lead to the SAME pipe, it's some form of single-pipe system. If you have separate zones of individual single-pipe loops, all of this might be possible, but it takes extremely careful study of the system and exacting engineering.

Kal Row

speaking of raw materials....

as the cost on steel in Europe skyrockets, soon vei$$mann will have to move them to the usa production - just like the Grundfos people did, yep, it's all coming back here, since the cost of raw materials in the usa is dropping like a rock as compared to the rest of the world - even china - it's our saving grace - the vei$$mann may be the best, but it isn’t twice a good as the ultra, they will have to be a little more competitive somehow

DaveGateway

I heard raw material prices are skyrocketing

Steel, cast iron scap, copper, cement and of course oil, all going up thanks to China's explosive growth and our desire to pump them with dollars for a lot of cheap crap.

rb_5

recycled

Hi Jerry,

I think I mentioned recycling - but you are bang on - I'll check out William McDonnough ..."the end of useful life is that it becomes food or is efficiently reused" is great stuff.

Hot Rod gave me an awesome book a few years back called Natural Capitalism - opens the eyes to what the construction trade does - it is downright embarrassing…if the public people only knew the environmental abuse our industry collectively represents we’d all be fined or at least levied a heavy fee on business permits.

RB

rb_5

jerry scharf_2

my tupence on boiler testing

I don't think going the burner efficiency route with max combustion temp measurements is the right way to go. It may be easier than what I am thinking, but it may not give the real numbers.

We need to come up with a set of standardized load situation. One where you can repeatedly expose the boilers to a predictable set of loads, within a percent or 2.

Then we need to get repeatable input fuel. I would think that getting one tank of LP fuel that all the tests were run against would be one way. Natural gas seems harder, unless you got a cryogenic tank to hold a big batch. Doing a batch test on BTU content is not very hard, that's what bomb calorimeters are for.

With consistent loads and consistent fuel sources, you can look at the usable heat capture rate of the boilers, which is what the game is really about. I don't care how you lose the efficiency, it could be in the burner or heating the room.

Places like Oak Ridge must be able to do these tests.

jerry