Dear Mário,
I’m currently working on a VRF system and am modeling it
this way:
·
The actual system uses Mitsubishi City Multi VRF units with heat
recovery capability. I am not sure if this approach will work for other
manufacturers of VRF systems.
·
My model uses water source heat pumps (WSHP) for each zone. These
should capture the ability of the VRF system to “shift” energy
around when some zones are heating while others are cooling. The model is
running without error, but I have not addressed the details of the energy
portion yet. That part will go similar to the following…
o The WSHP
fans will be assigned power (efficiency and pressure rise) to match the VRF
fans.
o The
WSHP heating and cooling coils will have a “simple” power
consumption coefficient. If I can use 0 power, that will be best, since the
VRFs don’t use power at each zone except for the fans. If I can’t
use 0 due to some E+ restriction, I’ll probably make it equivalent to a
COP as high as possible and then report that energy in a Custom Meter and use a
Custom Decrement Meter so it can be removed from the total electricity use.
o The WSHPs
have a gas boiler with efficiency of 1.0 for supplemental heat and an electric
chiller with COP of 1.0 for supplemental cooling. The 1.0 efficiency / COP
values are used for simplicity so that energy used by the boiler and chiller is
essentially the same as the load.
o I
will report the boiler and chiller energy and “post-process” their
energy using the manufacturer’s part load efficiency equation. It occurs
to me just now that I may be able to apply curve values which mimic the
manufacture part load performance and avoid the post processing….
The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Mário
Sent: Sunday, May 16, 2010 4:12 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Variable Volume Refrigerant System
Hello
Does anyone have any ideas on how to model a variable volume refrigerant
system, like a VRV or VRF system in which you have one exterior machine linked
to vários interior terminal machines?
Thank´s
MN
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