VRV systems

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Hi All,
Which system shall we select in system type for TFA(DOAS)
units for VRV system when we are taking PVVVT system per zone.

Any response will be appericable

Thanks
Sambhav.

sambhav tiwari's picture
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Joined: 2011-09-30
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I am having trouble figuring out how to model successfully the VRV systems
with an air cooled condenser. I am using a Make up Air unit ( SYSTEM =
PVAV) in a dummy zone and then attaching my evap unit system to it via
OA-FROM-SYSTEM. my individual evap units are currently PVVVT, with air
cooled condensing units set to variable speed.
I followed the instructions in that powerpoint presentation that was passed
along the users group and have not been able to get it to work.
my unmet hours in heating are very large. is this the approach that anyone
has used before and made it work? does anyone have any tips/tricks to make
this thing work?

By the way, i sent this message once with the powerpoint attached, and it
was too large and i needed to wait for the moderator, so i sent this to get
faster answers.

thanks,

--
Rob Hudson

rdh4176's picture
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Joined: 2011-02-14
Reputation: 0

I am having trouble figuring out how to model successfully the VRV systems
with an air cooled condenser. I am using a Make up Air unit ( SYSTEM =
PVAV) in a dummy zone and then attaching my evap unit system to it via
OA-FROM-SYSTEM. my individual evap units are currently PVVVT, with air
cooled condensing units set to variable speed.
I followed the instructions in that powerpoint presentation, which is
attached, that was passed along the users group and have not been able to
get it to work.
my unmet hours in heating are very large. is this the approach that anyone
has used before and made it work? does anyone have any tips/tricks to make
this thing work?

--
Rob Hudson

rdh4176's picture
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Joined: 2011-02-14
Reputation: 0

Rob,
If you are using 3.64, I've had the same problem. Not sure if it's a bug, but I've sent example files and problems to Jeff Hirsch without any answer. Maybe we will hear something soon.

Sam Mason

Sam Mason's picture
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Joined: 2011-09-30
Reputation: 0

After playing with the inputs, i have discovered that the unmet hours appear
when the system is set to heat source = heat pump. for some reason this is
not working properly...

rdh4176's picture
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Joined: 2011-02-14
Reputation: 0

I'm not sure if it is a 3.64 issue or not, but I was able to represent a VRV
(PVVT) system using version 3.63b and I followed the power point example for
the most part.

It might not be a bad idea to try version 3.63b if you have the time. Since
my experience with this first VRV system model, I have not had another VRV
project that would allow me to try and model them in 3.64 version.

Good luck, keep us posted on what you uncover...

pkg

Pasha Korber-Gonzalez's picture
Joined: 2011-09-30
Reputation: 600

I found this same approach resolved my underheated hours problem in a PVAVS
system on a 3.64 model I'm working on now.
...must be an upgrade with the new version with these challenges. I was
happy it solved my model issues easily when I figured out this control
parameter.

You should read in the DOE-2.2 reference docs if you haven't looked there
yet, it should give you some insight to how your specified system types are
behaving in your model file. If you can't find these docs, let me know and
I can forward them to you.

Pasha

Pasha Korber-Gonzalez's picture
Joined: 2011-09-30
Reputation: 600