Fan Coil with DHC: Defaulting as VAV - low efficiency

Hi all,

I am working with the DF Heating and Cooling with HB HVAC templates. The drop down menu has Fan Coils with District Hot Water and District Cool Water. The electricity results are extraordinarily high. When I compare it with other modeling tools, it is clear that the default must be VAV. I want to implement DHC with Electronically Commutated Motors for a large efficiency gain. How do I fiddle with the DF component and HB template to make that change?

The difference, for example, is a 55% efficiency gain over what the LBT fan electricity results are in comparison to other tools with ECM Fan Coils.

Thank you!

Bumping this one again.

Hi @Geo_curious ,

I am sorry that I did not respond to this at the time but there are two new features from when you first posted this, which may help you here:

First, there are a set of new inputs on the “HB Sizing Parameter” component that allow you to set the efficiencies of all HVAC equipment to align with a particular version of ASHRAE. Just plug a building vintage into the eff_standard_ and the translation process to OpenStudio will automatically perform a sizing calculation. This admittedly takes a while but then all of those sizes will be used to set the efficiencies of the various pieces of HVAC equipment (fans, pumps, chillers, boilers, etc.).

This should probably align better with what you were expecting.

Second, there is a “DF Detailed HVAC” component that enables you to assign detailed HVAC systems built with the Ironbug plugin. Ironbug has roughly one Grasshopper component per HVAC component so you can assign all of the efficiencies that you want this way.

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