[Equest-users] ERV Impact

[Patrick J. O'Leary, Jr.]

yep.  how are you controlling the erv?  interlocked with the supply air 
fan so they're on all the time during occupied hours?  that'll do it.  
you spend more energy running the wheel and those inefficient erv supply 
and erv exhaust fans than you save via the energy transfer of the wheel.

my experience has been to set the ervs to function based on a delta t 
between the outdoor air and the exhaust air.  the best delta t will vary 
depending where your project is but in my hot/dry 2b zone i've found a 
delta t of 20 was good, a delta t of 26 was peak before the energy 
savings headed south again.

also, you don't need to delete/remove the ervs to see energy savings.  
just set up parametric runs with the different delta t you want to test 
at & you can compare the savings via the comparison reports.  just don't 
forget to a) set the parametric run for delta t, assign the unit(s) with 
ervs, and give it a delta t.  these are multiple inputs per air handler/erv.

sample:



On 11/30/12 12:59 PM, Andrew Clagett wrote:
>
> Hello all. After finalizing my building and obtaining what appeared to 
> be reasonable output, I removed the ERV devices (modeled at 85% 
> efficient cross-flow air to air heat exchangers) from the model to 
> ascertain the energy savings attributable to those devices.
>
> And my total energy consumption went *DOWN* over 6%! Inexplicably, 
> 'space cooling' and 'pumps & aux.' energy consumption has decreased by 
> a  far larger amount than 'space heating' increased. I would have 
> expected both of those values to increase along with the 'space 
> heating' energy consumption (which did increase).
>
> Anyone have any idea why that might be?
>
> *Andrew Clagett, *PE, LEED AP
>
> Mechanical
>
> d |  206.436.0494 o | 206.448.3376 e | andrewc at hargis.bizv-card 
> <http://www.hargis.biz/vcards/Andrew%20Clagett.vcf>
>
> *HARGIS***
>
> 	
>
>      mechanical . electrical . telecommunications . security
>
>
>
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