eQuest Runaround Heat Recovery

Topic: Simulating runaround heat recovery in eQuest requires modifying the standard air-to-air heat recovery system

Suggest selecting system 'PSZ' for DX cooling or 'SZRH' for chilled water; other system selections may work satisfactorily. The following parametric components were utilized to obtain a combined $5,000 in savings (initially, without parasitics) on a $90,000 per year utility bill in the Pacific Northwest on a pair of 'PSZ' systems with heat recovery using 100% outside air.

$ Adjust the supply and returns statics of the main unit to
$ account for the increased pressure drop, originally:
$ SUPPLY-STATIC = 5.25
$ RETURN-STATIC = 2.60 (less delta-P, due to partial exhaust flow)
$ Example, given the above initial statics
SUPPLY-STATIC = 6.00
RETURN-STATIC = 3.00
$ Change the following keyword to YES in a parametric run; all other heat
$ recovery parameters are ignored when set to NO for the baseline case:
RECOVER-EXHAUST = NO
$ Runaround heat recovery recovers sensible energy only, no latent
ERV-RECOVER-TYPE = SENSIBLE-HX
$ Specify OA and EXH flows if only a portion of the exhaust is recovered
$ Partial recovery example
ERV-OA-FLOW = 46960
ERV-EXH-FLOW = 28590
$ Potentially the effectiveness can increase to 0.75 if a two-pass coil used
ERV-SENSIBLE-EFF = 0.53
ERV-RUN-CTRL = OA-EXHAUST-DT
ERV-RECOVER-MODE = OA-HEAT/COOL
$ FLOAT gives maximum heat recovery but recovers even unwanted heat, so
$ use the setting for temperature control
ERV-TEMP-CTRL = MIXED-AIR-RESET
$ modulation capacity control simulates variable-speed pumping
ERV-CAP-CTRL = MODULATE-HX
$ input maximum runaround pump power consumption here, it will be switched
$ on only when the ERV is activated
ERV-HX-KW = 4.5
$ use main unit's fans for heat recovery
ERV-FANS = HVAC-SUPPLY/RETURN
$ Keywords STANDARD and PREMIUM may alternately be specified here
ERV-MOTOR-CLASS = HI-EFF
$ Set the ERV statics to zero, since it is NOT a separate unit
$ in series with the main unit; i.e. pressure losses are 'unswitched'.
$ If left undefined, they will default to 1.5 inches:
ERV-OA-STATIC = 0
ERV-EXH-STATIC = 0
$ This setting eliminates condensation and frost simulation warnings
ERV-FROST-CTRL = USE-CAP-CTRL

However when the parasitic loads of the additional supply/return fan energy and runaround pump power are accounted for, eQuest demonstrates again that is difficult to break even with runaround heat recovery in this relatively mild maritime climate:

(click on the image to see a larger version)