Applying the inverse "Pareto Principle" to heating appliance efficiency

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lsayre
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Post by lsayre » Tue. Dec. 29, 2020 7:30 am

The "Pareto Principle" is more commonly known as the "80/20" rule. Invert it and you get my 20/80 rule. Apply it to wood and coal burning "peak" (or appliance "listed") efficiency and you get:

If your appliance is listed as being 90% efficient it will be nominally 90% efficient during only about 20% of the burn cycle, and demonstrably less at other times. The efficiency likely exhibits some derivation of the classic Bell Curve.

This may work for other heating fuels as well, including 300% efficient heat pumps, but on a more seasonal 20/80 basis.

Another application is for solar in the N/E Ohio area. Solar panels are rated as to peak 100% efficiency Watts, and then you are also given the 80% Watts figure, which is supposed to reflect a more "real world" output expectation. But in the no sun gloom of N/E Ohio winters the real world seems to better reflect the 20/80 rule.

Wind power may better overall reflect the 20/80 rule also, with this being year round, as those who have bought residential windmills whereby to make electricity for their homes will generally attest (if honest).


 
User avatar
lsayre
Member
Posts: 21781
Joined: Wed. Nov. 23, 2005 9:17 pm
Location: Ohio
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Lehigh Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW), ComfortMax 75

Post by lsayre » Fri. Jan. 01, 2021 4:51 pm

Let's say that 90% efficiency is reached over 20% of the burn cycle, and a more typical 65% efficiency is achieved on average over the remainder of the burn cycle.

Overall Efficiency = [(90% x 20) + (65% x 80)]/100 = 70%

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