Quote:
Originally Posted by kostas
T3 (hair dryer): 49°
T4 (HRV exit air): 45,7°
T2 (hair dryer outlet): 38,5
T1: (ambient air inlet): 21°
PP solid core efficiency: 88,2%
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That is the efficiency for 1 of the 2 channels, the formula we are using to calculate that (perceived efficiency) is:
100% * (T4-T1) / (T3-T1) == 88,2%
For the other channel we would get:
100% * (T4-T2) / (T3-T2) == 68,6% <-- wrong formula
100% * (T3-T2) / (T3-T1) == 37,5% <-- correct
It appears something was not symmetrical during your testing and it could be the mass of air through both channels.
Warmer air is lighter, especially when one stream is 294 Kelvin and the other is 322 Kelvin (9,5% more density for the colder air.) but that alone doesn't account for the 28% difference. Were all the ductwork and the fans identical?
With this unballance you do indeed get nice and warm air inside but you are exhausting more air out than re-enters, and the exhausted air is warmer than it should be. On top of that the surplus of exhausted air will be made up by air entering your house via other ways, unheated.
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In your test the distanced PP core performed poorly. Due to it's construction the two channels in that one will
definitely have a different resistance. If your fans cannot handle this different airpressure then you will get weird and unbalanced results, like 45%-ish efficiency in 1 channel.
Kostas, could it be you overlooked something?
I was as surprised as Ham789 was when you reported that the distanced PP performed so poorly when compared to the stacked PP. We feel it should be the other way around.
If you still have that core and the other testing-equipment could you in some way repeat the test and report T1 - T4 (including T2) and then rotate the core 90 degrees and repeat the test?