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Nice Pellet Stove Story with a Twist

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by teddy1971, Sep 6, 2008.

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  1. slowzuki

    slowzuki Feeling the Heat

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    Another note that Joe knows for sure, the heat pump performance falls off as temp drops, and climbs as the temp difference falls. Here in NB next to Maine, they are a 3 season device and only act as an electric resistance heater in the 3 worst months.

    I'm trying to get my parents to install a mini-split for the shoulder seasons to cut back on their windows open + woodstove running approach to fall and spring.

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  2. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Yeah, we have fancy calculator software that can figure out where the balance point is.

    At current electric and pellet prices, and using southern NH climate data, the balance point is just a few degrees below zero. Given the warmer climate in Weymouth, MA, where the author of that article lives, it's likely that the cost of operation on comparable systems would still be cheaper for the heat pump than for pellets, since it will likely never drop below the balance point.

    That's at current prices, of course. It won't hold true in the long-term, unless something really crazy happens to the market.

    Joe
  3. cac4

    cac4 New Member

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    12k btu's on 1kw? and this system costs how much??

    and it works below 0....not "down to 37", like a previously referenced article quoted?

    Weymouth is not significantly warmer than "southern NH"... I guess it depends on how you define "southern NH". Keene is quite a bit chillier than say..."hampton".
    But it any case, Weymouth ain't anything like Florida.
  4. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Can't speak for prices down by you, but that system would cost $9500, if I installed it again, today.

    Yup. Some systems have significantly-lower operating temperatures than others. The Fujitsu units I mentioned will work down to 5 degrees above zero. Some other systems will work down as low as -30. Granted, -30 is well below the balance point, so it would be silly to operate at that temperature, if another heat source was available, but some homes are heat-pump-only due to deed restrictions and the like.

    Personally, I really like hybrid systems using a heat pump for mild weather, and switching to another fuel source when the weather gets colder. That can be done manually (eg, when it gets below a certain temp, you light up the pellet stove), or in the case of an automatic central heating system, an outdoor thermostat can take care of the transition, and be adjusted as fuel prices change.

    By the charts, the heating load is about 10% less in Weymouth than in southern NH. That's figuring for Concord NH. It's enough warmer to push the balance point a few degrees.

    Joe
  5. MCPO

    MCPO Minister of Fire

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    [quote author="CTwoodburner" date="1220903241"]C'mon now. Heat pumps work. Are they the answer for everyone, during every season - well, no. What if you just use a heat pump in the shoulder months - thus, only burning the stove December - March in the NE?? What if you get one of those multi-function units - a/c and heat?[/quo

    Yeah , heat pumps might be more practical for the shoulder months but the truth is my oil furnace don`t burn a whole lot of fuel during those months either. It`s those really cold Dec -Mar months when the heat pump efficiency drops.
  6. DiggerJim

    DiggerJim Feeling the Heat

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    Since you have some expertise in the area, please explain this:

    Sept 06 - spent $100 on electricity for lights, refigerator, washer, dryer, stove and no more than $15 of pellet stove fans
    Sept 07 - spent $50 on electricity for lights, refrigerator, washer, dryer, stove and heat pump.

    According to the author the only difference between these two months was the number of days in the billing cycle (1) and the use of zones with setback thermostats.

    In the world of physics it is not currently possible to produce more energy than consumed except in fission or fusion reactions. Unless his heat pump had a small nuclear power plant there's no way he added that to his usage mix and reduced his bill unless something else changed. He claims he did more with less but he wasn't using electricity to heat his house in 06. There's no electric baseboard or old heat pump that a new efficient one is now displacing - he displaced no more than $15 of electricity for running the pellet stove (and that assumes the stove was on 24x7 in September based on the user manual for his stove).

    But as someone more familiar with these things, could you tell us what heat pump produces electricity as a by-product of its use so I can buy one? It appears to be the solution to this country's energy problems. If I get 4 of them I'll not use any electricity at all and be warm too - I eliminate $3,500 of oil and $2,700 of electrical use a year. Pays for itself year one.
  7. MCPO

    MCPO Minister of Fire

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    Exaggerations on efficient heaters abound these days , especially the European ones. It seems the latest advertising implies that anything with a European tag on it is more efficient than anything made here in the US.
    Last year my neighbor was talked into installing a Buderus (German) oil furnace ($2K+ more than my Burnham boiler) since the heating contractor convinced him it was energy efficient and save him big bucks and hundreds of gallons of oil vs his old boiler.
    The Buderus really looks nice and it runs rather quiet . It has some serious looking bells and whistles / lights and gauges that monitor different aspects of heating to assist efficiency .
    However I was immediately skeptical of the exaggerated claims and told him so , mainly because my (reasonably new) Burnham boiler runs at 85 % efficiency ( readout report after servicing yearly by technician) and for the life of me can`t imagine getting much more from an oil boiler regardless of who built it.
    Guess who was right? After a year we saw little difference in his oil consumption that could be credited to his beautiful new Buderus.
    Two weeks ago we installed a pellet stove in his house.

    Makes me think of this old addage: If it sounds too good to be true, it usually is.
  8. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    He has two stoves installed, according to the article.

    So call it $30, and now you're down to less than $25 difference, which is easily within the realm of year-to-year fluctuations.

    Joe
  9. DiggerJim

    DiggerJim Feeling the Heat

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    It also says he only fired the 2nd one when it got really cold (in the teens). That did not happen in Sept 07 (or Oct for that matter either). There were 50 degree days in Sep 07 vs. 61 in Sep 06 (203 in Oct 07 vs. 331 in Oct 06). So he certainly didn't run the second stove (if we're to believe him). It's also not at all likely that he burned stove #1 24x7, so the $15 max cost of electric for it was probably more in the dollar or two range. That makes his story even more fanstastical.

    So his magic heat pump must generate electricity as well or he made other changes that were not represented in the article and makes his story B.S. You simply cannot add the heat pump into the mix and use less total electricity - especially in those 2 months where the other uses of electric would dwarf heating (the heating demands represent 10 and 57 gallons of oil for Sept & Oct respectively, the electric equivalent for heat doesn't nearly approach what would be used for lights/stove/water/etc.).

    But, I'm still interested in whatever heat pump you know of that can acheive this so I can buy a few for my house.

    Interesting side note, 07 & 06 were the two coldest (in that order) winters in the last 30 years in Massachusetts in terms of degree days. The only other one to come close was 02-03 --- the rest were at least 500 degree days warmer for the season. Don'cha love global warming?
  10. yoscratch

    yoscratch New Member

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    he also said that now that he is using the heat pump, he also uses a set back thermostat whereas (do you like that?) with the pellet stove it was just on all the time.
  11. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Not sure where you're getting those oil equivalents, as there is no formula that converts degree-days to gallons of oil.

    In any case, based upon actual experience with these sort of conversions, I find his numbers to be thoroughly believable, albeit at one end of the normal range. He most likely tossed a few CF bulbs in and used the electric oven a bit less, and that easily covered the small difference. In very mild weather like that, a heat pump is going to be very efficient, and a few small changes in electrical usage would easily cover the increase due to the heat pump. I'm sure there were some changes that he didn't report there, but they were probably trivial things like CF bulbs, not some major conspiracy to hide the truth, like you're making it out to be.

    All these technologies have their various places. Just because someone found that his home, coupled with his family's usage of heat was cheaper with a heat pump than with a pellet stove, is not to say that pellet stoves are a bad idea, or that his experiences were representative of the average.

    Joe
  12. MCPO

    MCPO Minister of Fire

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  13. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Most contractors work along the Walmart way of thinking: do a lot of cheap systems. Heat pump systems are not cheap. They also are not for every application, and it requires a good it of understanding of engineering to determine if a heat pump is a good match for a particular system.

    Most contractors just go with what they know, and install heavy, single-pass cast iron boilers, and quite often warm-start boilers, which are horrifically inefficient (we're talking ~55% system efficiency). Because that's what they are comfortable with, and they know it will work, without having to think about it. Many contractors are technically-competent as tradespeople. Not too many understand the underlying engineering behind these systems well enough to design a proper hybrid system.

    And... few air-source heat pumps are efficient enough to give that kind of performance. I can think of maybe three systems that can realistically work in our climate in the northeast. So we're talking about cutting-edge technology which only a few contractors bother to deal with. It's a small portion of the market.

    Joe
  14. DiggerJim

    DiggerJim Feeling the Heat

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    First I have to thank you for the past few days' exchanges. They have provided an exceptional case study for my son's class sessions in critical thinking.

    As for your points today - I understand as a heat pump guy you might not be aware of how oil is used & projected but the equivalents of degree days to gallons of oil is a rather trivial exercise. (The figures I noted were from the Mass Oilheat Council using data from the National Oilheat Research Alliance.) Oil dealers do this calculation all the time -- degree days can be translated into BTUs of supplemental heating needed which can then be translated to # of gallons of oil. The oil dealers use this to determine when to come fill the tank if you're on automatic delivery. In this case the Mass OC says that the 50 degree days of Sept 07 required 1,390,000 BTUs or 10 gallons of oil (there are 139000 BTUs in a gallon of heating oil). This actually helps us calculate exactly how much electric he would have used heating with pellets -- 6.8 KWH or 68 cents at 10 cents a KWH.

    So the other "trivial" changes you suggest he might have made and running his heat pump saved him an additional $54.01 - quite a remarkable feat. Since he claimed he made no other changes, that means his heat pump delivered 1,390,000 BTUs AND GENERATED 540KWH more than it used!!! One of those heat pumps with the 12.5 EER (12,500 BTUs/KWH) would have consumed 111.2 KWH and cost him $11.12 and increased his bill (after offsetting the pellet stove consumption he replaced) by $10.44 overall. To acheive his $54.69 in overall savings, his magic combo heat pump generator, generated a total of 651.2KWH (111.2 used for heat + 540 to reduce bill by $54). It's a wonder that this isn't on the front page of newspapers all over the country.

    In light of your experience with conversions like this, WILL YOU PLEASE tell me what heat pump I can buy that generates more electricity than it uses? I've asked a few times here but you haven't answered - I guess you missed the request but I'd really really like to know. I will in fact give you 100% of my first year's savings if you'll only tell me what heat pump to buy to get this result. My father spent a lifetime in the HVAC industry (as did my grandfather) both residential and commercial so all of us kids were kind of immersed in it from birth by the way :)

    I don't expect you'll take me up on my offer and I'm pretty much done with this thread. My only purpose lately has been to demonstrate how people will easily believe, and then blindly defend, claims that make no rational sense and are not physically possible. As I've said, it's been a very instructive example of critical thinking (or lack thereof).

    I do have the secret of how to convert your car to run it on ordinary tap water in case you're interested. You may have seen it on You Tube and possibly some of the stories on how the oil companies are conspiring to keep it off the market. Ordinarily I think this costs $99 on the Internet, but I'll share it with you in return for your secret of the magic heat pump.

    Have a sparkling winter,
    Jim
  15. globewyre

    globewyre Member

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    Maybe he made the mistake I made years ago. The electric bill might have been an estimated reading. I didn't realize they estimated bills until i got a "correction"
  16. DiggerJim

    DiggerJim Feeling the Heat

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    Not unless they estimated his bill for several months last winter (or the previous one). He "saved" money in multiple months.
  17. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    While you're studying critical thinking, you might just want to study up on the dangers of making assumptions, and perhaps the benefits doing research. Heat pumps are a small fraction of my business. Most systems we install are oil, wood, or gas (in that order). My website is linked right in my signature at the bottom of every post. Perhaps you missed it?

    The term is "k-factor." It's defined as "heating degree-days per gallon." The thing is, k-factor includes the efficiency of both the system and the structure itself. Having worked for oil companies in the past, I can tell you that actual k-factors vary from 5 to 25 in probably 95% of structures.

    In other words, one structure might consume 10 gallons of oil to supply heating to offset 50 degree-days, whereas another building in the same climate may have only used 2 gallons.

    Apparently, you are imagining that the building in question had a k-factor of 5. From practical experience, a building like that is one which is uninsulated, with single-pane windows, massive air leaks, and an extremely inefficient heating system (probably an old coal steam boiler with an early oil-conversion burner). It does not sound like that is what the house in question is like.

    And, of course, heating degree-days do not exactly correspond with energy consumption. A basic oil system will be more efficient under heavy load, so a month of warm days with a single cold day would require less fuel than a month of slightly-cool days, even if both months have identical heating degree-day numbers. A high-efficiency heat pump (or a properly-installed mod/con boiler, for that matter) will be the opposite, and operate most efficiently in the latter hypothetical month than in the former. The k-factor is a statistical number used for estimates of gross fuel consumption, not something that you can use to determine actual consumption in any given month (particularly when weather is not ideal for the given system).

    There simply is no direct, universal equivalent between heating degree-days and either btus needed or gallons of oil consumed. Each structure has a different efficiency, based upon the building envelope, daily use, and the efficiency of the heating system.

    Interesting. Do you happen to know how much the author of that article pays for electricity, or are you using the national average blindly? I pay over 15 cents per kwh. It's entirely possible that the author of that article is paying different rates for the heat pump's power, versus the power for the rest of the house - dual-metering is common here in NH, and I have trouble imagining that electric service in Mass is so behind the times as not to allow for it.

    In other words, additional power used by the heat pump may have had a small economic impact, whereas small changes in other power usage would have had larger economic impact.

    I've deleted the rest of your mathematical conclusions, since it is readily apparent that they are based upon assumptions that you have made, rather than actual data. Math works great... but only when the data being used are accurate.

    One thinks you would be familiar with the variability of the ratio of heating degree-days per gallon, then...

    You've done an excellent job of demonstrating exactly that.

    Let me know when you've met with the author of that article and done an engineering analysis of his house to determine the actual heat loss of the structure under varying weather conditions, charted out the weather for the given months (day by day, not monthly totals) and examined his electric bills to determine how many kwh those dollar values actually equate to.

    Until then, you are doing an excellent job of demonstrating the principles of making and blindly defending claims without scientific validity.

    Joe
  18. mkmh

    mkmh New Member

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    Wow, interesting stuff all the way around.
    I read the original article and thought to myself "Yep, I can see where he's coming from. Electric heat gets kind of a bad rap, whereas lots of folks assume that heating with pellets is going to save them tons of cash".

    It never occurred to me that the author of the article was claiming that his heat pump system was literally paying him back. One thing for sure, i'm certain it never occurred to the author that his artcile would undergo this kind of scrutiny!
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