A guess at ballparking 'Manual J' heat loss

 
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lsayre
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Post by lsayre » Mon. May. 18, 2020 12:24 pm

An R^2 of 0.9976 for a straight line "best fit" ran through the plotted data is a strong confirming indicator that HDD's are indeed linear. Perfection would be a fit with an R^2 of 1.0000.

 
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Post by Lightning » Mon. May. 18, 2020 12:25 pm

I'm probably splitting hairs, since fuel usage can be estimated from HDDs. I didnt realize the other factors could skew it much to worry about. :oops:

 
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Post by Lightning » Mon. May. 18, 2020 12:35 pm


Advertise on Coalpail.com

 
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Post by lsayre » Mon. May. 18, 2020 12:49 pm

Ah, when someone using Wikepedia as their platform whereby to lend credibility challenges the linearity of HDD's and provides reference for same so as to poo-poo their validity it pays to go right to the poo-poo source and see what the referenced material touting non-linearity is actually talking about. Here it is:

http://journals.ametsoc.org/doi/pdf/10.1175/1520- ... 2.0.CO%3B2

The study finds that the R^2 correlation between the combined linear CDD (Cooling Degree Days) formulas and linear HDD (Heating Degree Days) formulas is a completely abysmal R^2 = 0.62, indicating that there is no correlation possible between the two separate and independent methodologies. But when pressed to separate the two linear formulas and use them separately as intended the very same study concludes (see top left on page 1421) that by using CDD's their precision of agreement between math model and real world was within an amazing 2% (or R^2 = 0.98), and their precision of agreement between real world and math model for HDD's was a nearly as amazing 4% (or R^2 = 0.96). Thus the conclusion of the study used to bash HDD's and proclaim them to be non-linear actually verifies both their precision and their linearity.

 
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Post by lsayre » Mon. May. 18, 2020 12:53 pm

You found the poo-poo source just as I did, and beat me to posting the link. I hope you understood that it was not poo-poo at all. 8-)

 
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Post by Lightning » Mon. May. 18, 2020 1:28 pm

Haha right on :lol:

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Post by lsayre » Tue. May. 19, 2020 9:16 am

A 130,000 BTUH output boiler would heat my house down to about -107 degrees F. outside.

70 - -107 = 177

177 x 1.4 = 247.8

247.8 x 523 = 129,600 BTUH output required

 
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Post by lsayre » Tue. May. 19, 2020 1:59 pm

The lowest recorded temperature in Antarctica was -128.6 degrees F. in 1983.

A Coal Gun or AA 130 would likely meet the 99% design criteria If my house was to be located in one of the coldest places in Antarctica. Once in a blue moon or so I may not be able to keep it above about 45-50 degrees inside, but 99% of the time I could probably keep it at 70 degrees.

Here is the current weather forecast for the south pole: https://www.timeanddate.com/weather/antarctica

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