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<DIV><FONT face=Calibri>
<DIV><FONT face=Calibri>Dear Matthew,</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>..." </FONT>Is there a way to force HAP to supply a
constant air flow through a "system"<BR>(this includes specifying return air and
outside air requirements) and<BR>calculate the cost of providing the cooling and
heating water to the "system"<BR>and "zone" reheats? Any explanations
would be helpful. "...<BR></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>The air quantity through the cooling coil that is
indicated by the HAP is the minimum air quantity that warrants that you get the
desired space conditions. It is called the Dehumidified Air Quantity,
(DA). The air that you deliver through the ducting to the space is
called Supply Air, (SA). Normally DA is equal to SA. You have to
maintain this flow of the mixture of return/outside air over the coil or you
will not obtain the desired temperature and RH in the space.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Now, if by some reason you want to increase the
flow of air, make a bypass of Return Air only into the plenum of the
fan. The return air is thermaly neutral to the space and will
increase the air quantity without afecting your psychrometric
process.</FONT><FONT face=Calibri></FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>This is done by example in night clubs or other loads
with a very large latent component. The supply air quantity in these
applications is some times too small due to the very low Apparatus Dewpoint, and
you will have to increase the air quantity to ensure that you have a proper
distribution of air in the space. Aim at least to maintain 6 air changes
per hour in the space.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Some high quality air handling units of modular
design, have an external or internal bypass duct that runs over the
coil.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>You can make the bypass of air with a mix of outside air
and return air directly from the mixing box passing over the cooling coil, but
the use of bypass of return air only is better to achieve a good control over
the RH in the space.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Kindly feel free to demand more information on this
subject.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Calibri>Best Regards</FONT></DIV>
<DIV><FONT face=Calibri>Eduardo
Barrigana</FONT> </DIV></FONT></DIV></BODY></HTML>