[Bldg-sim] Fan modulation for VRF fan coils

[Aaron Smith]

Hi Fred,

 

>From my experience, VRF controls have usually just given the user 2 to 4
steps of fan speed (not infinitely variable) but now that I look at one of
the controls manuals (see Mitsubishi City-Multi below), they have an "Auto"
option as well.  It doesn't explain how auto mode works but I know some
fan-coil unit controls adjust the fan speed based on how far the room
temperature is from setpoint - perhaps this does the same?

 

Aaron

 

 

 

 

Aaron Smith, P.Eng 

M&R Engineering 

  _____  

From: Porter, Fred AEC [mailto:FPorter at archenergy.com] 
Sent: Tuesday, May 06, 2014 9:13 PM
To: bldg-sim at lists. onebuilding. org (bldg-sim at lists.onebuilding.org)
Subject: [Bldg-sim] Fan modulation for VRF fan coils

 

Anyone,

I had been led to believe that the fans modulated on many VRF indoor units.
However, I am now being told by a rep that this is not the case for any
larger VRF fan coils, where it really would be valuable as the design W/cfm
isn't minimal. Currently the designer does not want the fan coils cycling,
and wants to deliver OA to a mixing box, not separately to the space in
parallel as was our original recommendation.  

 

Does anyone know a reputable source that contradicts what I've been told? 

 

Fred

 

Fred Porter, BEMP, LEEDC AP

Senior Energy Analyst

Architectural Energy Corporation

A Member of NORESCO Energy and Sustainability Services

2540 Frontier Ave, Suite 100, Boulder, CO  80301

Phone 303.459.7425 |  fporter at archenergy.com

www.archenergy.com

 

 

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