VSD savings via infiltration
Last Post 02 Sep 2015 08:47 PM by jonr. 3 Replies.
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dannybten23User is Offline
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24 Dec 2013 02:13 PM
Hello, I am trying to calculate the energy savings a VSD fan on a ventilation system will create. Calculating the savings of the actual fan is easy, but how would I calculate the savings of less cool air being forced out of the building? The building is positively pressurized, and less CFM of ventilation will mean less cool air (or hot air in a cold climate) will be forced out, and a lower load on the HVAC. I was using H=CxMxT, (c= the specific heat of air, M being the mass of air, and t being the temperature difference). Is that correct? Do you have a better formula? Any help will be appreciated! Thanks, Dan
jonrUser is Offline
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24 Dec 2013 05:20 PM
It's around .005 watt hours to heat 1 cubic foot of air by 1F. In the winter, positive pressure pushing warm, moist air into the wall may not be a good idea.
chrsUser is Offline
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02 Sep 2015 05:26 PM
If you are mainly looking at A/C costs rather than heating costs, the calculations discussed so far are looking only at sensible heat but not at latent heat--the humidity in the outside air that the A/C needs to remove. That then depends on your climate and how much dehumidification is actually done.
jonrUser is Offline
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02 Sep 2015 08:47 PM
For that matter, using a HRV or ERV means that you can get ventilation while retaining most of the air's energy. On the other hand, positive pressurization causes more air to skip the HRV/ERV and go through leaks.
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