Compare the cost of heating energy

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Compare the cost of heating energy




by Christophe » 08/01/08, 16:52

Quick upload comparison of heating energy costs taken (with some modifications) from this document: https://www.econologie.com/forums/fichier-bi ... t4247.html

There are some approximations but it gives a good idea the cost of useful energy. Indeed; the yields are taken into account in the article.

We see, for example, that wood heating in chimneys is very expensive because of the rather catastrophic performance of a chimney ...
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Re: Comparison of the cost of heating energy




by Did67 » 20/01/08, 23:10

Christophe wrote:Quick upload comparison of heating energy costs taken (with some modifications) from this document: https://www.econologie.com/forums/fichier-bi ... t4247.html

There are some approximations but it gives a good idea the cost of useful energy. Indeed; the yields are taken into account in the article.


Some data are highly questionable. For the subject I know best, wood pellet heating (pellets), the current data, in my case (Alsace), are as follows:

- boiler efficiency (Okofen PESK 15 - condensing) = 100,6% (according to official tests from the Austrian institute that certifies boilers - "up to 104%" according to the manufacturer); not 70% ; in a general way, serious brands (Austrian or German) all reach around 90%, the best exceed this figure ... I have a lot of documentation on this subject.

- currently, we find pellets in bulk at around 180 € per tonne + 29 € unloading (price including VAT) for pellets to the German standard Din + (the most severe); and not € 330 as indicated; this factor depends a lot on the region (wooded or not, competition or not)


[color = blue] I strongly doubt that "air-to-air" heat pumps will maintain a COP of 3 or more as soon as the outside temperatures go negative. This may be the case for “ground-to-air” or “water-to-air” heat pumps which benefit from a source of calories at an almost constant temperature. The COP of an "air-to-air" pump is inversely proportional to the indoor air / outdoor air temperature difference. The laws of thermodynamics are ruthless. The manufacturers add a heating resistance in front of the evaporator to be able to maintain a sufficient temperature inside !!!


Christophe wrote:We see, for example, that wood heating in chimneys is very expensive because of the rather catastrophic performance of a chimney


Exact. In addition, regardless of the green, it is very polluting - even if the resource is renewable. It obviously depends on whether the wood is dry or not, whether the fire is open or not ... On the other hand, pellets are a standardized industrial product (8% humidity, etc.) whose combustion is controlled by a sophisticated regulation in the case of the improved boilers that I mention...
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by Christophe » 20/01/08, 23:20

Some precisions:

a) 330 € is the price in a "bag" of 15kg sold generally 5 € ...
If it is offered in this packaging it is because some people use it while thinking of doing business .... but it is not the case

b) For the condensing wood yields I ask to see the additional cost and the resistance over time ... the pellets being supposed to be as dry as possible (10%) I see badly the potential gain of the condensation which is very small. ..70% is therefore closer to the actual efficiency of the pellet stoves ... then do not forget that a wooden boiler is clogged more than a gas boiler ... So without maintenance beware of the drop in efficiency ...

c) Yes for the COP of Air Air (although you have to be a scam to sell air air or it freezes strong) but do not forget that these prices (it is well noted) do not take into account investment or maintenance account ...in this case, close to reality, the price of kwh "geothermal" would soar...worst: I bet that 50% of the PACs currently mounted will simply never amortize... (HS before the return point) and we are only at the beginning of the wave of escrology which arrives ...

ps: I have corrected your quote again ...
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by Did67 » 21/01/08, 09:12

Christophe wrote:Some precisions:

a) 330 € is the price in a "bag" of 15kg sold generally 5 € ...
If it is offered in this packaging it is because some people use it while thinking of doing business .... but it is not the case

b) For the condensing wood yields I ask to see the additional cost and the resistance over time ... the pellets being supposed to be as dry as possible (10%) I see badly the potential gain of the condensation which is very small. ..70% is therefore closer to the actual efficiency of the pellet stoves ... then do not forget that a wooden boiler is clogged more than a gas boiler ... So without maintenance beware of the drop in efficiency ...


Sorry, I don't know how to quote properly. While waiting for an explanation, I continue in blue:

- I'm talking about boilers and not stoves
- I can send you the test report: the Okofen PESK 15 reaches 100,6%, ie 7% more than the same model without condensation (tests by BLT Wieselburg - Austria); So here is the gain, verified by tests, with pellets at 8% humidity ... Don't forget that combustion gives off water - there is no water in the gas, however Efficient gas boilers are condensing. It seems to me that you made a mistake in reasoning. The heat of the condensation of the water contained in the pellets is "neutral" in the balance: it is consumed to evaporate the water from the pellets then recovered in the condenser; this is lost in non-condensing models ...
- the additional cost, for this model, is € 2 excl. tax (half of which is reimbursed by the tax credit)
- I opted for condensation, but I admit: a) profitability, under current conditions, is questionable - but what will the prices be in the future? ; b) it is technically a risk - corrosion resistance of the condenser, etc ... I do not particularly encourage this option, even if by conviction I adopted it ("it is not because a resource is renewable that it must be wasted "!)
- other machines, without condensation, reach yields of more than 90%; for example Hargassner or Guntamatic (according to official tests and not the brochures)
- finally, on these machines, there is a daily automatic scraping of the turbulators ...

I find you pessimistic about the technical aspects of pellets. I have been thinking for over a year - there is material. But I am optimistic. The proof: I "rocked" - but I do not claim to be necessarily right ... "See you in 10 years", as the song says?

If the data in the table that you have published concerns stoves and not boilers, I understand better. But I misunderstood then ...


Christophe wrote:c) Yes for the Air Air COP (although you have to be a scam to sell air air or it freezes strong)


It seems to me, however, that it sells more than pellet boilers in Alsace! The climate may warm up, I think we will still have frost !!!
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Re: Comparison of the cost of heating energy




by bham » 21/01/08, 09:54

Did67 wrote: - boiler efficiency (Okofen PESK 15 - condensing) = 100,6% (according to official tests from the Austrian institute that certifies boilers - "up to 104%" according to the manufacturer); not 70% ; in a general way, serious brands (Austrian or German) all reach around 90%, the best exceed this figure ... I have a lot of documentation on this subject.


How much did you pay for your Okofen boiler?
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by Christophe » 21/01/08, 10:43

Did67 wrote:Sorry, I don't know how to quote properly. While waiting for an explanation, I continue in blue:


You just have to put in "quote" each quote, remembering to close ([/ quote]) the previous one before opening a new one. Edit one of your messages that I corrected and you will quickly understand.

Did67 wrote:- I'm talking about boilers and not stoves


I think there are far more stoves than boilers installed ... I speak in general. We can always do great things but at what price and reliability?

Did67 wrote:- I can send you the test report: the Okofen PESK 15 reaches 100,6%, 7% more than the same model without condensation (BLT Wieselburg - Austria tests); so here is the gain, verified by tests, with pellets at 8% humidity ... Do not forget that combustion gives off water - there is no water in the gas yet every high-performance gas boilers are condensing. It seems to me that you made an error of reasoning there.


Reasoning error ???

Well where would the water come from if it doesn't come from the moisture in the pellets or the humidity in the air? In fact we evaporate it to recondense it then? To my knowledge, wood only contains a maximum of 2% of hydrogen ...

Sorry I think that condensation on a wood boiler is not wise for 3 reasons: performance gain, additional cost and maintenance ...

This is in contrast to gas condensing boilers (strictly speaking fuel oil) where there is a real potential gain possible. And still a lot of professionals refuse to install this because it's more pain than other things
. Better to make a 110% return for 5 years or a 90% return for 30 years?

Economically there is no photo !!

Did67 wrote:The heat of the condensation of the water contained in the pellets is "neutral" in the balance: it is consumed to evaporate the water from the pellets then recovered in the condenser; this is lost in non-condensing models ...


It's neutral, that's what I said above: so how do I get more than 100% return? Except for the H2 contained in the wood I don't see ...

Did67 wrote:- the additional cost, for this model, is € 2 excl. tax (half of which is reimbursed by the tax credit)


Ouch 2250 € for 15 points of return ... have you calculated the return on investment?

Did67 wrote:- I opted for condensation, but I admit: a) profitability, under current conditions, is questionable - but what will the prices be in the future? ; b) it is technically a risk - corrosion resistance of the condenser, etc ... I do not particularly encourage this option, even if by conviction I adopted it ("it is not because a resource is renewable that it must be wasted "!)


Well, that's all ...

Did67 wrote:I find you pessimistic about the technical aspects of pellets. I have been thinking for over a year - there is material. But I am optimistic. The proof: I "rocked" - but I do not claim to be necessarily right ... "See you in 10 years", as the song says?


It is not the techniques that worry me but the commercial aspect ...

Did67 wrote:If the data in the table that you have published concerns stoves and not boilers, I understand better. But I misunderstood then ...


This concerns boilers AND stoves but I will correct to put 80% efficiency on the boilers ...

Did67 wrote:
Christophe wrote:c) Yes for the Air Air COP (although you have to be a scam to sell air air or it freezes strong)


It seems to me, however, that it sells more than pellet boilers in Alsace! The climate may warm up, I think we will still have frost !!!


It's a lamentable fact, but the nuclear lobby is more powerful than that of the pellet sellers and people are idiots: when it goes on TV, it must be "true" ... It's up to us to educate them. ..

ps: last general remark, does anyone know how the boiler outputs are given for which operating range? It's probably like cars: ideal laboratory data over a very precise operating range.
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by Christophe » 21/01/08, 10:52

Some links to support the subject:

Pollution of pellets or pellets?

Personal video of a blue flame wood combustion

For did67: analysis of the combustion of pellet boilers (it is not noted, because of advertising problem, but there are Okofen among the 5 tested, I attended the conference and the gentleman clearly under enterndu):

Analysis of the combustion of biomass boilers

ps: Did67, I'm preparing an energy wood file for the site, would you agree to take some photos of your installation? (boiler + storage)?
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by bham » 21/01/08, 11:15

Christophe wrote: ps: last general remark, does anyone know how the boiler outputs are given for which operating range? It's probably like cars: ideal laboratory data over a very precise operating range.

I can not answer you, I can just tell you that I went to see a wood boiler / reverse combustion logs in operation at a private individual. The digital panel displayed 94 or 97% efficiency while the fumes were already at + 200 ° c. When you know that a low temperature fuel boiler with the same output comes out of the smoke at 120 ° C if I remember correctly, I came to doubt the display. I asked the salesperson to close the draft to lower the T ° of the fumes (and see the difference in efficiency) but he said that it was not good for the boiler.
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by Christophe » 21/01/08, 11:34

Uh idea: your 97% it would not be the combustion efficiency? It's not quite the same as the boiler output.

Anyway, it is not very serious the calculation of the boiler output with this theoretical method with wood whose quality (humidity in particular) and the PCI therefore are very variable but it is moreover what the laboratory of the forem used on this document: https://www.econologie.com/analyses-de-c ... -3544.html

To make a real yield calculation you have to put a calorimeter (2 T ° probes + flow meter) on the boiler and know perfectly the composition of the fuel and on this last point, with logs it is not even worth it think seriously ...
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by bham » 21/01/08, 13:40

Christophe wrote:Uh idea: your 97% it would not be the combustion efficiency? It's not quite the same as the boiler output.

Don't know! :|
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