#331 VRF tag suggestion

Alper Üzmezler Fri 30 Oct 2015

We are modelling a VRF system and have the following suggestion.


Kind: Marker Used With: ahu Used with ahu to mark an AHU as a packaged variable refrigerant flow unit(VRF).

Brian Frank Fri 8 Jul 2016


Is your suggestion to make this a new tag to describe the cooling mechanism, and if so then it might be a little better to name that tag vrfCool to match dxCool. If there is agreement, then I would roll it into the Heating and Cooling section:

AHUs should define their heating method using one of the following tags:

Cooling method should be defined using one of the following tags:

Leroy Simms Mon 11 Jul 2016

VRF is still a type of direct expansion (dx) cooling. I think vrf would be more of a sub category to dxCool and would be better added in addition to dxCool rather than in it's place.

For heating methods don't forget heatpump; which could be the only heating source or used in conjunction with any of the other heating sources mentioned.

Denis OConnor Mon 11 Jul 2016

From the 30,000 foot level;

the vrf sounds like a heatPump with a vfd on the compressor to vary the refrigerant flow……. some installations having the ability to provide simultaneous heating and cooling.

Alper Üzmezler Mon 11 Jul 2016

I agree with both comments.

I would say, it is similar to rooftop tag.

DX systems could be used as heat or cool. Solenoid valve switches the modes. Depending on geographical locations engineers specify dxHeat as first stage than elect or gas heat is second stage.

dxCool dxHeat (1st stage of heat) elecHeat (2nd stage of heat)

as a sub category of it, the refrigerant entering into the unit is variable.

We could use more explicit wording as vrflow.

Let's try wrap up the VRF systems as a whole instead of just one tag. I made a drawing to put my thoughts on the overall system.


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