Greetings,
Could you please provide some advice to the following case (the building belongs to System 7):
1. Proposed project is arranged with water cooled chillers and dry coolers (cooling towers of close type). They coolers were chosen because the chiller plant is supposed to operate at minus outdoor temperature conditions. Also following this approach there is a heat exchanger separating the dry coolers and condenser circuit, whereby the dry cooler loop is filled with a glycol/water mixture in order to prevent freezing.
2. The Baseline plant, as per app. G should have cooling tower. It has not been specified whether this cooling tower is of open or closed type and it has been prescribed a fix pump power value of 19 W/gpm.
The question is:
Should we model the Baseline also with dry coolers and glycol loop. There should be such option because in climate zones 6, 7 and eventually 8 and also by System 7, an open cooling tower will face problems and therefore a comparison between items 1. and 2. above will be made at not equal operating conditions.
You advice on the matter will be highly appreciated.
Thanks.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
May 29, 2017 - 4:06 pm
I think you are trying to design the baseline. It should be an open tower.
Vassil Vassilev
ManagerTermoservice
13 thumbs up
May 30, 2017 - 1:12 am
Hi Marcus,
Thanks for the reply.
Regarding the operation of an open cooling tower during low outdoor temperature. Is there some interpretation which would allow some amtifreezing preventions for the Baseline, because practically when the open cooling tower can not function during cold weather and at the same time there is a cooling load, it can not be covered.
Actually what could be the concept of Baseline modeling in such cases.
Thanks.
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
May 30, 2017 - 6:38 am
Hi Marcus, this is a relevant case. We use "super software" bent on modelling everything soooo accurately, and then we sit back and try to simulate JANK that does not fly in real life. And if the software even lets it run...somehow...we're bound to get a load of warnings that need explaining to the reviewers. Anyway, this could go on a list of 90.1 improvements.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
May 30, 2017 - 8:36 am
Why do you need to run a chiiler/tower at minus outdoor temperatures? Does not sound like cooling for human comfort.
Vassil Vassilev
ManagerTermoservice
13 thumbs up
May 30, 2017 - 8:47 am
That's right, it is for a Data center.
There are also some more question of how to model Data centers and computer rooms in LEED v3, which we've bben planing to send you tomorrow.
In general in 90.1 2013, app. G it has been clearly explained - some cases should follow systems 3 (4), some however system 11.
If we follow these rules, what should we do in terms of explaining it to revierers.
Thanks.