How can I model destratification fans?

asked 2022-09-19 11:42:20 -0600

Drew Morrison
253 ●4 ●5

I am modeling a building with 20’ ceilings in an assembly area, where the design calls for destratification fans. How can I model the energy impact of the fans? I know they will result in increased miscellaneous load usage which I can calculate easily, but I want to estimate the HVAC energy savings to confirm that they will be worth the cost and increased energy usage.

answered 2022-09-19 11:43:35 -0600

tinadarko
128 ●1 ●5

The easiest way to model destratification fans in Sketchbox is to simulate the energy savings impact they have on the heating and cooling load. By circulating air within the space, destratification fans reduce the load on the HVAC system.

First, you’ll need to create a separate shell for the space(s) with destratification fans, as the strategy will not apply to the entire space. Then create a measure for that shell with the following three components:

Internal loads > Miscellaneous equipment power
HVAC > Occupied cooling temperature setpoint
HVAC > Occupied heating temperature setpoint

The increase in equipment power can be calculated based on the capacity of the fans and their expected run time.

For the setpoints, adjust cooling up by one degree, and heating down by two degrees.

These setpoint adjustments are explained and validated in a 2005 article in the ASHRAE journal: “Saving Heating Costs in Warehouses.” The article is behind a paywall, here: https://technologyportal.ashrae.org/J...