I think I found a bug with the ERV feature in eQuest related to
temperature control. My input is as follows:
RECOVER-EXHAUST = YES
ERV-RECOVER-TYPE = ENTHALPY-WHEEL
ERV-SENSIBLE-EFF = 0.75
ERV-LATENT-EFF = 0.75
ERV-RUN-CTRL = OA-EXHAUST-DT
ERV-TEMP-CTRL = MIXED-AIR-RESET
ERV-CAP-CTRL = MODULATE-HX
ERV-HX-KW = 0.207
ERV-FANS = HVAC-SUPPLY/RETURN
ERV-OA-STATIC = 0.5
ERV-EXH-STATIC = 0.5
ERV-FROST-CTRL = USE-CAP-CTRL
The system shows heating savings as expected, and cooling savings during
summer periods, but during winter there is a large cooling penalty.
Hourly reports show an unexpected cooling load during winter night mode
operation. If I set ERV-OA-STATIC to zero, that cooling load goes away.
If I change to a fan located in the ERV, the unexpected cooling load is
still absent:
ERV-FANS = SELF-CONTAINED
ERV-EXH-KW/FLOW = 0.002
Thus, it appears that the heat gain due to friction in the heat wheel is
not taken into account for the OA setpoint during night mode when
ERV-FANS = HVAC-SUPPLY/RETURN. Has anyone else seen this problem?
The SELF-CONTAINED option appears to be a work-around, but it is not as
convenient for add-on heat wheels.
Thanks,
Doug Maddox, PE
Doug,
I very recently came across the same problem but haven?t been able to solve it either. If you haven?t tried it already, one workaround you might consider is to set the COOLING?SCHEDULE with OA temperatures below which cooling is unavailable. This will mitigate the winter cooling you are seeing. In my case it appears pretty helpful in making up for the bug but I haven?t looked at this approach enough to know for certain that it doesn?t cause any undesirable affects.
---
Billy Vreeland