Hello everyone,
I'm trying to model in eQuest a ventilation air machine (VAM), which is a
simple plate heat exchanger with an OA fan and an exhaust fan.
How can it be modelled to operate with an FCU type of system? (VAM for
fresh air heat recovery and FCU for cooling/heating).
Best regards
Nick Patsos
Nick,
eQuest limits the HVAC systems for a thermal zone to (1) air-side system
that may have reheat and/or supplemental heat, (1) baseboard heat source,
(1) exhaust system. To model the VAM system you need to create an
equivalent system to the overall systems operating in the thermal zone.
I think you can model your system by creating an exhaust fan (and schedule)
for the zone and incorporating the HEX into the FCU using Outdoor Air Heat
Recovery. You will need to make some adjustments to system performance
(e.g. kW/cfm) to make sure overall performance of the simulated system and
actual system align.
- Matt Hein
Hi Matt,
thanks for your answer. I have set an exhaust fan at zone level but the
problem is that still the Outdoor air heat recovery is not enabled under
the FCU system parameters.
Any further thoughts ?
Best regards
Nick Patsos
Mechanical Engineer
In the grand scheme of things it's all the same (air movement, heat source,
heat rejection, pumping, and controls). The devil is in the (eQuest
configuration) details.
I think I would use a packaged single-zone with reheat (SZRH) and adjust
the curves and other performance parameters to try and match the actual
FCU. Coil placement and other attributes are different but your best
efforts (and good documentation) are all you can give.
Anyone else have suggestions?
- Matt Hein
If this is actual equipment, not a theoretical study, it would be nice
if the equipment manufacturers had some advice on modeling. I know that
Climate Master tried to do this for a while on their Ground Source Heat
Pumps. All gone now I think.
But if it's real equipment, calling the manufacturer and saying "I'm
trying to model your equipment in EQuest" might at least give them the
vague hint that EQuest exists and is used for things that might make
their equipment more easily specified.
I mean, everybody gives AutoDesk details now, right?
OK, I'm dreaming, I know...
Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060
FAX +1 916 966 9068
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