4 Pipe FCU- Refrigerant lines (supply and return) instead of CHW lines

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Hi,

I am looking to model a custom built up unit ventilator for classroom
building. The UV in classroom is basically a 4 pipe FCU system. The HW is
supplied by natural gas boiler. Instead of CHW water lines, an outdoor
split system (air condenser) is utilized to run the refrigerant (supply
and return)lines to the UV.

In e-quest, if FC is used as system type, a CHW loop is required (which is
not present in this case). Therefore, for a custom system like this, is it
safe to model the air side system as "residential split unit" and HW loop
for the heating side? Since the cooling is provided by a split system,
I thought a RESYS2 system will be ok?

Has anybody encountered such type of system before to model in e -quest?

Thanks

energyengineer81's picture
Joined: 2015-12-28
Reputation: 0

Hi,

I think you can make do with a hot water PTAC, as long as you specify the performance of the DX cooling based on your outdoor+indoor unit for fan power.

Best,
Julien

Envoy? de mon iPhone

jmarrec's picture
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Joined: 2013-01-09
Reputation: 0

PTAC may not serve your purposes if the project unit ventilators have economizers. PTAC does not include the option for economizer. The PSZ system will work fine in either case ? with or without economizer. The DOE22Vol3 ? Topics manual mentions using the PSZ system to represent school classroom unit ventilators. See page 225.

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Jones, Christopher's picture
Joined: 2015-06-11
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