[Equest-users] LEED Comment for FAN EFLH--help please

[Michael Mantai via Equest-users]

What type of HVAC systems do you have in the baseline vs. proposed?  As noted in the comment, the baseline system fans should run continuous during occupied hours and cycle at night.  If your proposed case system has dedicated outside air systems, those fans would run continuously during occupied hours but other fans could cycle on temperature.  I’ve done schools that use a DOAS unit coupled with fan coils or heat pumps.  In the proposed case I set the DOAS to run continuous and set the fan coils/heat pump fans to cycle on temperature, which would result in less fan hours.  I’m also surprised your proposed fan kW is that much higher than baseline, so you might check that.

 

From: Equest-users <equest-users-bounces at lists.onebuilding.org> on behalf of Pasha Korber-Gonzalez via Equest-users <equest-users at lists.onebuilding.org>
Reply-To: Pasha Korber-Gonzalez <pasha.pkconsulting at gmail.com>
Date: Thursday, March 30, 2017 at 3:51 PM
To: eQUEST Users List <equest-users at lists.onebuilding.org>
Subject: [Equest-users] LEED Comment for FAN EFLH--help please

 

Hello fellow eQuesters,

 

I'm sure we all get the standard LEED review comment regarding Fan equivalent full load hours (EFHL).

 

I received this one on my current project (elementary school in Ohio with heat recovery units.)  I have confirmed that my fan schedules for both models are exactly the same.  But I do have drastically different EFLH values for the baseline (over 3,000) and proposed (less than 1,500).

I have made changes in my models, but I cannot seem to get the proposed hours over 1,600 of run time.  

 

QUESTION:  Do any of you have any experience of suggesting to the LEED Reviewer that it is possible to have this significant of difference between the two models hvac systems AND how can I show justification for these run hours??  Any advice & suggestions are welcomed at this time.

 

Here is the LEED comment I received with highlighted notes:

. Table EAp2-5 of the form indicates that the equivalent full load hours for interior fans in the Proposed and Baseline model are 1,200 hours (57,951 kWh/48.31 kW) and 3,702 hours (130,702 kWh/35.31 kW), respectively; however, it is unclear if the HVAC fans are modeled as cycling to meet the cooling and heating loads of the building during unoccupied hours. Table G3.1.4 in the Proposed building column requires that HVAC fans that provide ventilation air in the Proposed model must be modeled as operating continuously during occupied hours and cycled to meet the cooling and heating loads of the building during unoccupied hours, unless one of the exceptions of Table G3.1.4 are met. In addition, Section G3.1.2.4 requires that supply and return fans reflected in the Baseline model must be modeled as operating continuously during occupied hours and cycled to meet the cooling and heating loads of the building during unoccupied hours, 

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