You do have some pretty big loads. I don't know what your pool load is when indoors but I can tell you it takes about 112,000 btus to raise my 15000 gallon inground outdoor pool 1 degree.
gg
gg
Mission Impossible?
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my indoor pool is 12,000 gals. 14 x30 I run it 4 hrs a nite which dumps in about 75k per hour. I will hover in the mid eighties, when it gets cooler I will add some time on the clock, I have in floor heat in the room also which we don't need for comfort, use when we want toasty floors.
bigburner said:
So with that it would be 60-75lbs of dry wood in an efficient boiler. His pool is just under 4X the size. So a rough guess would be 240-300 lbs of wood per day.
I could be wrong but that is my quick math.
If we use 240 lbs and just say 3600 lbs per cord of hard wood= a cord every 15 days to heat the pool alone.
gg
My load is probably twice yours at 150KW peak.
15 to 20 cords seems sort of in the region.
The big issue is that you have an installed system using NG so mathematically I am not sure how you could justify it purely financially.
I would expect a lot more that $20,000.
15 to 20 cords seems sort of in the region.
The big issue is that you have an installed system using NG so mathematically I am not sure how you could justify it purely financially.
I would expect a lot more that $20,000.
Gulp ... total of 4 cords of aspen/pine (about 2.5 cords red oak equivalent) to heat our house for the whole heating season in northern MN.
These complex boiler systems make way more "cents" on large loads. Your heating 1500 sq ft home and a 800 sq ft shop, show me how 15k system pays back, [I know it's a better pay back on oil] There a term that's over used today but it holds pretty true for large heating loads. "economy of scale" Invest 40K into a system that is heating 15,000 sq ft there is a % advantage on the ROI. A BTU from wood is the same in either system. Natural gas isn't cheap, it is less expensive then some other fuels.
goosegunner said:
Recalculated I looked at your original post again I had used 44,000 gallons pool instead of 35,000. Yours would be 3X not 4X bigburner's pool.
So,
180-225lbs per day, use 180lbs assuming you can get 5000 btus/lb from the wood.
3600/180= a cord every 20 days for pool.
gg
A cord every 20 days for the pool plus the house--that is a lot of wood if you are buying it and moving it from the plle to the burner. Around here wood is selling for about $200/cord.It would be good exercise so there would be some savings by eliminating the gym membership.
Propane cost for me is twice and a bit more than those on NG.
It has been 3x.
So a major factor.
It has been 3x.
So a major factor.
Como said:
I have told my wife if we had natural gas instead of propane we would probably not be burning wood.
gg
Como said:
You have that right Como ! LPG. is 94 cents a litre here . When I installed my modcon lpg boiler 3 years ago it was 43 cents a litre , I guess it makes my payback on my EKO and storage that much sooner.
Huff.
Goosegunner - your math may be correct for bringing pool up to temp but your wood use assumption is way off. After the pool is at "set-point" The load is only the loss threw the building envelope, MUA etc.. Mine Example 4 hrs x 75,000 = 300,000 Btus per day, If my pool was 24,000 gals[twice as big] the load would not be any different [after reaching set-point] 300,000 per day. NOT 600,000 per day
bigburner said:
Could be way off but seems to me my pool at 15,000 gallons heats a lot easier than my cousins at 50,000 gallons.
Gg
you are missing my point, the load isn't the water after it's warm [set point]. If you put 15,000 gal pool in a building or a 50,000 gal pool in the same building and both were heated to a certain temp. The load to maintain the water temp is the same. There are some variables like surface tension, vapor pressure required MUA etc. But strip it down and it is the same amount of Btu's regardless of pool size. Look at this way - if I showed up at your house with 15,000 one gallon water bottles and it was all 72 F and you house was 72F after we carried them all in the house did we change the temp or the load? NO! Now my brother shows up with 35,000 more 72 F water bottles and we carry all those in, what happens to the load? Nothing. Its the delta T threw the envelope of the house, that is the load.
bigburner said:
I guess it makes sense as you explain it. It still seems odd that an olympic size pool could have the same heat loss as say a 10000 gallon pool in the same size structure.
My pool heating experiences are related to outdoor pool heating which varies greatly depending on outside conditions it is in the envelop of the great outdoors.
gg
Perhaps I can help.
At -20F the Manual J calcs are that it will take 150KW to keep the building at 65F.
Usually I do not keep the whole building at that temperature, so if I suddenly need to up the temperature I will need a lot more than 150KW to get it up to heat.
There are several things I do not like about the Manual J. One is wind, no taken into account and I know that one awindy day i need a lot more energy than a calm day.
The other is sun, I think it is about 20F at the moment and cloudy, but I still get solar gain. My gut feel is that I use half as much energy as I would during the night for any given temperature.
I am Anglo Welsh, where I lived most of my life there was not a lot of difference in day/night temperature and it was a LOT damper. There was not a lot of difference between day and night energy usage like there is here.
I did actually try and use a UK sources to work out my heat loss. However they have a fixed minus temperature of about 25F. Not a variable you can alter.
I would be very tempted to use wood chips in a similar situation in the UK as you would not have the freeze issue.
Where I was born is on the same Latitude as Juneau in Alaska, but I am sure the weather conditions are totally different. And so would the heating solution.
At -20F the Manual J calcs are that it will take 150KW to keep the building at 65F.
Usually I do not keep the whole building at that temperature, so if I suddenly need to up the temperature I will need a lot more than 150KW to get it up to heat.
There are several things I do not like about the Manual J. One is wind, no taken into account and I know that one awindy day i need a lot more energy than a calm day.
The other is sun, I think it is about 20F at the moment and cloudy, but I still get solar gain. My gut feel is that I use half as much energy as I would during the night for any given temperature.
I am Anglo Welsh, where I lived most of my life there was not a lot of difference in day/night temperature and it was a LOT damper. There was not a lot of difference between day and night energy usage like there is here.
I did actually try and use a UK sources to work out my heat loss. However they have a fixed minus temperature of about 25F. Not a variable you can alter.
I would be very tempted to use wood chips in a similar situation in the UK as you would not have the freeze issue.
Where I was born is on the same Latitude as Juneau in Alaska, but I am sure the weather conditions are totally different. And so would the heating solution.
I live in Northern Michigan and have an effecta lambda 35 with 1,000 gallons of storage.
I am heating my house, garage and hot tub and would have it no other way.
I also know of 2 others that are using effecta lambda 60 kw boilers with 2,000 gallons of storage to heat 9-10,000 sq. ft. home/business shop.
IMO you would need this same type of system. However, before generically saying this you need to do a heat loss study of your home, pool and pool room.
Hope this helps!
Brian
I am heating my house, garage and hot tub and would have it no other way.
I also know of 2 others that are using effecta lambda 60 kw boilers with 2,000 gallons of storage to heat 9-10,000 sq. ft. home/business shop.
IMO you would need this same type of system. However, before generically saying this you need to do a heat loss study of your home, pool and pool room.
Hope this helps!
Brian
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