Just spent some time over at the HVI institute (
http://www.hvi.org/resourcelibrary/proddirectory.html) and reviewed some information on HRVs.
I focused on units that had a high Apparent Sensible Effectiveness (ASE) in the 90% range.
One of them, the Fantech 30005R, had a 92% ASE at 32 degrees Fahrenheit (F) for Heating
I wanted to figure out how cold/hot the air would be when brought into the house during the winter/summer.
I found this definition:
Apparent Sensible Effectiveness (ASE) – The term used in the CSA C439M standard for testing HRVs to describe the temperature rise of the outdoor air passing through an HRV. The effectiveness includes the effect of motor heat gain, cross leakage gain and casing gain. It is usually numerically higher than the sensible recovery efficiency of the HRV. When the flows of indoor and outdoor air through the HRV are equal, the sensible recovery efficiency equals the temperature rise of the outdoor air divided by the temperature difference between the outdoor air entering the HRV and is expressed as a percentage.
I interpret that to mean: Temp Rise / Temp Diff = ASE
or Temp Rise / (Inside Temp - Outside Temp) = ASE
or Temp Rise = ASE * (Inside Temp - Outside Temp)
From the HVI Literature, I have the ASE at 92%, and the Incoming Air at 32 degrees (F). I will stipulate an interior temperature of 70 degrees (F).
Inputting the numbers, I get:
Temp Rise = 0.92 * (70 - 32 F)
Temp Rise = 0.92 * (38 F)
Temp Rise = 34.96 F, round to 35 degrees F
I believe this means that the incoming air should have a temperature of 67 degrees F (32 F incoming + 35 rise F).
Am I doing this correctly?
Do the same calculations hold for cooling? If it is 95 degrees outside, 70 degrees inside, will the incoming air be 72 degrees? They don't list SRE or ASE for Cooling, but they do list a Total Recovery Efficiency of 18.
Thanks,
toddmanqa