Modeling Separate Ventilation System (eQuest)

asked 2018-02-16 11:44:18 -0500

ivanadriane gravatar image

Hi all,

I am trying to model a system serving a residential unit in eQuest. The ventilation air is being provided by a rooftop DOAS unit that is ducted directly into the unit. Heating and cooling is provided by a separate WSHP that cycles on and off to meet the load. As an example, one unit will have a ventilation rate of 45 CFM and a design supply flow of 570 CFM.

I have the WSHP modeled as a PSZ and uses OA-FROM-System to get outside air from the DOAS unit. I have my min flow set so that the unit provides 45 cfm all the time, and then ramps up to the design flow of 570 CFM when heating and cooling is needed. The two issues I am having are:

  • System is not ramping up to design flow in heating, but seems to be working in cooling.
  • Am I double counting my fan power for the ventilation air? Because I am using OA-FROM-SYSTEM is the 45 CFM to the space being counted for in my zone system AND my DOAS system?

Thanks for any help!

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