Bug with Secondary Loops?

2 posts / 0 new
Last post

Dear All,

We have created a fairly complex model of a building with chilled beams.
When we connect the chilled beams to secondary CHW loops, we get the
following error:

Loop: secondaryCHW_CB40 has a coil curve generating
a negative capacity ratio. Check the loop supply
temperature, 71.F, for consistency with the coil curves

OR

Loop: secondaryCHW_CB41 has a coil curve generating
a negative capacity ratio. Check the loop supply
temperature, 181.F, for consistency with the coil curves

Two observations:
(1) The CHW loops obviously have lower supply setpoints, 60F in this case.
(2) When we connect the chilled beams to the primary loop, then this
error disappeares.

I would appreciate some feedback on what could be causing this.

Best regards,

?mer Moltay, LEED AP BD+C, ASHRAE BEMP, ASHRAE CPMP, BREEAM Assessor
Mimta EcoYapi
Hekimsuyu Cad. 559. Sk. No:39 34255 Kucukkoy
Istanbul Turkey
Tel: 90-212-617-2296
Fax: 90-212-617-2297
Mobile: 90-533-957-1394
www.eco-yapi.com

Omer Moltay's picture
Offline
Joined: 2011-09-30
Reputation: 0

Dear James,

Just tried it both ways, yes we do get the same error with both 2-way as
well 2-way valves.

Please note that while we have something like 40 chilled beam systems,
we only get this error for secondary loops connected to a certain group
of these chilled beam systems.

Thank you,

Omer Moltay's picture
Offline
Joined: 2011-09-30
Reputation: 0