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<TITLE>RE: [Equest-users] VAV with Electric Reheat</TITLE>
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<P><FONT SIZE=2>John,<BR>
The primary heating coil in the air handler operates on the hot water loop.<BR>
It is just the terminal units that have an additional electric resistance coil that is used in the cooling season to raise the air temperature of the zone if the internal loads of the zone drop for some reason.<BR>
<BR>
That's why I need the both the hot water loop and the electric resistance.<BR>
<BR>
Best,<BR>
Omar<BR>
___________________________<BR>
<BR>
Omar Katanani<BR>
Sustainable Design Engineer<BR>
Email: omar@ecoconsulting.net<BR>
<BR>
<BR>
EcoConsulting (Lebanon)<BR>
Nahas Building, 4th floor<BR>
4 St-Maron Street / Georges Haddad Avenue<BR>
Postal Code: 2028 5806 SAIFI<BR>
Beirut, Lebanon<BR>
Tel: +961 (0) 1 971 255<BR>
Mobile: +961 (0) 3 045 045<BR>
<BR>
<BR>
EcoConsulting (UK) Ltd<BR>
28 Marshalsea Road<BR>
London, SE1 1HF<BR>
Tel: +44 (0)207 939 0989<BR>
Fax: +44 (0)207 939 0981<BR>
Website: www.ecoconsulting.net<BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: John Aulbach [<A HREF="mailto:jra_sac@yahoo.com">mailto:jra_sac@yahoo.com</A>]<BR>
Sent: Fri 7/16/2010 2:11 AM<BR>
To: Omar Katanani; equest-users@lists.onebuilding.org<BR>
Subject: Re: [Equest-users] VAV with Electric Reheat<BR>
<BR>
You have an electric heating system !! There IS no hot water flow !! Get rid<BR>
of the hot water loop !!<BR>
<BR>
John Aulbach<BR>
<BR>
<BR>
<BR>
<BR>
________________________________<BR>
From: Omar Katanani <omar@ecoconsulting.net><BR>
To: equest-users@lists.onebuilding.org<BR>
Sent: Thu, July 15, 2010 1:44:24 AM<BR>
Subject: [Equest-users] VAV with Electric Reheat<BR>
<BR>
<BR>
<BR>
Dear all,<BR>
<BR>
I was using a VAV system, with the reheat source being the hot water loop. I<BR>
specified the Reheat delta temperature by trial and error to 20F. Everything is<BR>
fine.<BR>
<BR>
Now I got updated info from the client saying that the source of the reheat is<BR>
electric. I am getting an error message:<BR>
<BR>
"Hot Water Loop has zero design flow. Check input for consistency, or specify<BR>
design loads."<BR>
<BR>
I read a couple of discussions. I understand that many factors will affect this<BR>
issue. The "Hot Deck Maximum Supply Temp", the "Reheat Delta Temp", and the<BR>
"Zone Entering Max Supply Temp".<BR>
<BR>
First of all, is the sum of the first two equal to the third?<BR>
<BR>
My main question is how to get reasonable results, knowing that the main heating<BR>
source is the hot water loop, and the electric reheat is just to fine tune the<BR>
temperature of zones experiencing different loads or so...<BR>
<BR>
I played with all values but I can't figure out the pattern. I know that the<BR>
design temperature of the zones is 70F, and that the temperature that is<BR>
supplied to the zone should be 30 degrees higher than the zone temperature<BR>
(70+30=100F).<BR>
<BR>
Any advice on how to choose the "reheat delta temp" and the "hot deck maximum<BR>
supply temp" is greatly appreciated.<BR>
<BR>
Many thanks,<BR>
Omar<BR>
<BR>
<BR>
___________________________<BR>
<BR>
Omar Katanani<BR>
Sustainable Design Engineer<BR>
Email: omar@ecoconsulting.net<BR>
<BR>
<BR>
EcoConsulting (Lebanon)<BR>
Nahas Building, 4th floor<BR>
4 St-Maron Street / Georges Haddad Avenue<BR>
Postal Code: 2028 5806 SAIFI<BR>
Beirut, Lebanon<BR>
Tel: +961 (0) 1 971 255<BR>
Mobile: +961 (0) 3 045 045<BR>
<BR>
<BR>
EcoConsulting (UK) Ltd<BR>
28 Marshalsea Road<BR>
London, SE1 1HF<BR>
Tel: +44 (0)207 939 0989<BR>
Fax: +44 (0)207 939 0981<BR>
Website: www.ecoconsulting.net<BR>
<BR>
<BR>
<BR>
<BR>
</FONT>
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