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<P><FONT SIZE=2>Dear all,<BR>
<BR>
I'm sorry I've been nagging a lot lately, but believe me, you guys are my only support!<BR>
<BR>
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 25F. Everything is fine.<BR>
<BR>
Now I got updated info from the client saying that the source of the reheat is electric. I am getting an error message:<BR>
<BR>
"Hot Water Loop has zero design flow. Check input for consistency, or specify design loads."<BR>
<BR>
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".<BR>
<BR>
I tried specifying the hot deck max supply temp to 70F, I got the results attached in the pdf. However, the gas consumption part of the space heating is negligible compared to the electric, while I thought both will be of significant ratios!<BR>
<BR>
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 to fine tune the temperature of zones experiencing different loads or so...<BR>
<BR>
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).<BR>
<BR>
Any advice on how to choose the "reheat delta temp" and the "hot deck maximum supply temp", or any other input parameter you feel that it affects, is greatly appreciated.<BR>
<BR>
Many thanks,<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: Omar Katanani<BR>
Sent: Thu 7/15/2010 11:44 AM<BR>
To: equest-users@lists.onebuilding.org<BR>
Subject: VAV with Electric Reheat<BR>
<BR>
<BR>
Dear all,<BR>
<BR>
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.<BR>
<BR>
Now I got updated info from the client saying that the source of the reheat is electric. I am getting an error message:<BR>
<BR>
"Hot Water Loop has zero design flow. Check input for consistency, or specify design loads."<BR>
<BR>
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".<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 source is the hot water loop, and the electric reheat is just to fine tune the 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 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).<BR>
<BR>
Any advice on how to choose the "reheat delta temp" and the "hot deck maximum 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>
</FONT>
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