[Equest-users] Excessive cooling capacity and "insufficient heating capability" warnings

[Gonzalo Lema]

Hi Julien,
Sorry for that, it was my first question in the forum.

Please find it attached.

Best,

SUMAC
Gonzalo Lema | Mechanical Engineer | LEED GA
Tel: +1.773.857.7906 Ext 7009 (Chicago, USA)
Tel: +1.305.814.8805 (Miami, USA)
Tel: +511.253.5355 (Lima, Perú)
Tel: +593.4.600.0613 (Guayaquil, Ecuador)
Tel: + 571.3151985 (Bogotá, Colombia)
glema at sumacinc.com<mailto:glema at sumacinc.com>
www.sumacinc.com<http://www.sumacinc.com/>

From: Julien Marrec [mailto:julien.marrec at gmail.com]
Sent: Wednesday, November 19, 2014 11:18 AM
To: Gonzalo Lema
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Excessive cooling capacity and "insufficient heating capability" warnings

Hello,

You should include your inp file or at least the relevant section, it'll be much easier to debug and see which parameter is not set the way it should.
Best,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec<http://www.linkedin.com/in/julienmarrec>
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr<http://www.linkedin.com/in/julienmarrec/fr>

2014-11-19 17:07 GMT+01:00 Gonzalo Lema <GLema at sumacinc.com<mailto:GLema at sumacinc.com>>:
Hi,

I finished my baseline energy model. However, my problem is that the auto-size DX cooling capacity is too high (625 ton) while the proposed design has a 90 ton chiller.
I also had a lot of trouble trying to meet heating load hours, and could only satisfy them by putting air dT=20F in the reheat option. If I put less dT or more dT the unmet load hours increase.
[cid:image001.jpg at 01D004A0.CB3C75C0]

The warning continues to appear for most of the zones though (but the unmet load hours is zero):
**WARNING**********************************************************************
             ZONE EL1 WSW Zone (fG.z1)
             might have insufficient heating capability.
             Check that the SYSTEM or ZONE HEATING-CAPACITY plus this
             ZONEs BASEBOARD-RATING is adequate to maintain the ZONE
             specified DESIGN-HEAT-T for the calculated peak ZONE load
             (see LS-A or LS-B for the ZONE peak load.)

             SYSTEM S1 Sys (PVAVS)
             which supplies the above listed ZONE, has a design heating
             coil exit temperature, HEAT-SET-T,(plus any zone reheat)
             below its MAX-SUPPLY-T or the ZONE DESIGN-HEAT-T, which
             might account for the insufficient heating capability.

             ZONE EL1 WSW Zone (fG.z1)             has a THERMOSTAT-TYPE
             of REVERSE-ACTION, which, when added to the issues listed
             in the messages above, will cause excessive underheating.



When fulfilling the heating capacity (with reheat dT= 20F), the cooling capacity raised dramatically. Thus, heating and cooling seem to be correlated, but I can’t find why the cooling capacity is so high for a 37230 gross sq ft building.
I have 27 VAV zones in the building

Thanks in advance for your help


SUMAC
Gonzalo Lema | Mechanical Engineer | LEED GA
Tel: +1.773.857.7906 Ext 7009<tel:%2B1.773.857.7906%20Ext%207009> (Chicago, USA)
Tel: +1.305.814.8805<tel:%2B1.305.814.8805> (Miami, USA)
Tel: +511.253.5355 (Lima, Perú)
Tel: +593.4.600.0613<tel:%2B593.4.600.0613> (Guayaquil, Ecuador)
Tel: + 571.3151985<tel:%2B%20571.3151985> (Bogotá, Colombia)
glema at sumacinc.com<mailto:glema at sumacinc.com>
www.sumacinc.com<http://www.sumacinc.com/>


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