[bldg-sim] Energy Recovery in eQUEST

[shruti narayan]

We have modeled a 100% OA AHU system with Energy Recovery in eQUEST based on 
the following control mechanism.

Enthalpy Wheel type- recovering both sensible and latent heat,
Operating mode - both heat/cool,
Make up air temperature control- Mixed Air Reset
Capacity Control- Bypass OA
Operation-OA Exhaust DT
OA/Exhaust DT- 5degF

As stated by others previously, the energy savings potential can vary 
markedly depending on the effectiveness of the control sequence. An ERV that 
operates continuously can incur a significant fan energy penalty. In 
addition, it may recover heat when the heat is not needed, thereby 
increasing cooling energy. A properly controlled ERV may prove to be cost 
effective, while the same ERV improperly controlled may actually increase 
energy usage and cost.

The questions are:

1. To relieve the static pressure drop (not to provide control), a bypass 
damper has been incorporated into the design on both the exhaust and supply 
decks.  Intention is for the damper to open when the energy recovery is off, 
thereby reducing the static pressure drop.  How should one model the bypass 
dampers to accurately account for the static pressure relief…   perhaps a 
schedule of pressure drop or fan energy tied to the ERV status?

2. Also hourly reports obtained from the current model for " ERV fraction of 
OA bypassed around the HX ". Indicate a fraction of air being bypassed when 
the ERV is on, however it gives a value of 0 when the ERV is off, which 
should not be the case. The fraction of OA being bypassed should be 1 when 
the ERV is off. What could be wrong? Any thoughts or suggestions?

This perhaps adds onto the previous thread of in-depth discussion on Energy 
Recovery, but having been through the Bldg-sim archive and the DOE 2 manual 
we have not been able to find an answer to the above issues. Any direction 
would be really appreciated, either in the modeling inputs or using post 
processing to get the Energy Recovery with bypass dampers to show accurate 
savings.

Thanks



======================================================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM