[Equest-users] ERV - Heating to zero

[Bruce Easterbrook]

Hi Prem,
The 99% heating design for Phoenix is 38F, so that will jump your 
temperatures. A buildings total energy consumption can be in the range 
of 30% for lighting.  eQuest also has high defaults for W/SF for 
lighting.  I would check these first to make sure the lighting levels 
are where they should be.  An ERV recovers latent energy as well which 
will reduce energy consumption if you are controlling humidity as well.  
I think that for an ERV to heat you have to give it a heater and control 
it's output temperature or it just dumps into the space and the AHU's 
make up the difference.
I don't think no heating is necessarily out of line for your climate.  
You need to get into your sim file and take a look at what is happening 
in finer detail.
Bruce Easterbrook P.Eng.
Abode Engineering

On 09/07/2013 10:45 PM, Sundharam, Premnath wrote:
>
> Hello All,
>
> I am modeling a packaged single zone with ERV in phoenix, AZ on a 
> facility that is 24x7 and has more than 75% OA.
>
> When I apply ERV, the fan energy increases, a slight savings in the 
> cooling energy, which I can understand. However, practically there is 
> zero heating consumption. Obviously, something is wrong. Here's a 
> screen shot of my input at the ERV tab. I tried both with leaving the 
> design OA flow/Exhaust Flow blank and with specifying a value -- no 
> change -- they produce zero heating consumption.
>
> I did just a portion of the building in Trane TRACE and it did the 
> same thing first -- practically no heating energy consumption. Then, 
> thought maybe this is what is happening:
>
> 1.Winter outdoor air is at say 30F
>
> 2.Space exhaust air temp is at say 66F
>
> 3.If the ERV effectiveness is 76%, then ERV could raise the OA from 
> 360F to 57F.
>
> 4.If the required space temp for winter is 68F.
>
> 5.Then, are the people load, lighting load and plug load providing the 
> rest of the heat from 57F to 68F -- since this is a 24x7 facility?
>
> It turns out in Trane Trace, if I knock the people sensible and latent 
> to 1 btu then I am seeing a significant space heating energy 
> consumption with ERV (still below my base case without ERV).
>
> I tried this same thing in eQuest -- didn't work -- no change in 
> heating energy consumption.
>
> I searched through the list and one other user has experienced similar 
> results but no solutions yet.
>
> Any help would be greatly appreciated.
>
> Thanks,
>
> Prem
>
> *Premnath Sundharam, AIA, LEED AP BD+C, BEMP, CEM*
>
> Architect  |  Senior Associate
>
> psundharam at dlrgroup.com <mailto:psundharam at dlrgroup.com>
>
> *DLR Group*
>
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>
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