[Equest-users] VAV with Electric Reheat

[John Aulbach]

 You have an electric heating system !!  There IS no hot water flow !! Get rid 
of the hot water loop !!

John Aulbach




________________________________
From: Omar Katanani <omar at ecoconsulting.net>
To: equest-users at lists.onebuilding.org
Sent: Thu, July 15, 2010 1:44:24 AM
Subject: [Equest-users] VAV with Electric Reheat



Dear all,

I was using a VAV system, with the reheat source being the hot water loop. I 
specified the Reheat delta temperature by trial and error to 20F. Everything is 
fine.

Now I got updated info from the client saying that the source of the reheat is 
electric. I am getting an error message:

"Hot Water Loop  has zero design flow. Check input for consistency, or specify 
design loads."

I read a couple of discussions. I understand that many factors will affect this 
issue. The "Hot Deck Maximum Supply Temp", the "Reheat Delta Temp", and the 
"Zone Entering Max Supply Temp".

First of all, is the sum of the first two equal to the third?

My main question is how to get reasonable results, knowing that the main heating 
source is the hot water loop, and the electric reheat is just to fine tune the 
temperature of zones  experiencing different loads or so...

I played with all values but I can't figure out the pattern. I know that the 
design temperature of the zones is 70F, and that the temperature that is 
supplied to the zone should be 30 degrees higher than the zone temperature 
(70+30=100F).

Any advice on how to choose the "reheat delta temp" and the "hot deck maximum 
supply temp" is greatly appreciated.

Many thanks,
Omar


___________________________

Omar Katanani
Sustainable Design Engineer
Email: omar at ecoconsulting.net


EcoConsulting (Lebanon)
Nahas Building, 4th floor
4 St-Maron Street / Georges Haddad Avenue
Postal Code: 2028 5806 SAIFI
Beirut, Lebanon
Tel:       +961 (0) 1 971 255
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EcoConsulting (UK) Ltd
28 Marshalsea Road
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Tel: +44 (0)207 939 0989
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Website: www.ecoconsulting.net


      
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