Hi

How’s everyone doing?

I have one question for you if someone can help me out. It’s just “work around” question where I need to understand how to model this particular kind of system in OS (preferably) or energyPlus. I am doing this greenhouse in openstudio (a pdf attached for greenhouse geometry & HVAC system) where small chambers with no fenestration are for mushrooms (65F, 80-90% RH) & big chambers (with fenestration) are for normal plants (85F with 60%RH). As the greenhouse is on roof-top (something like gotham greens - http://gothamgreens.com/our-farm/), we have constraints on structure loads & HVAC heavy equipment installations.

Majority of cooling load is because of high LPDs (28W/sf for germination & plant growth), envelope loads & ventilation loads. We are also the HVAC designer of the project & calculated the cooling load as 326 tons(!!) for 6500 sq project. We cannot install such a heavy chiller on the roof & building owner can provide us only 50 tons of cooling from his chillers. We figured out that evaporative cooling can be appropriate for the project with very high ACH (78 maximum & 5 minimum) for plant growing chambers (85F). For heating we will use baseboards or radiant heating with natural gas boilers as source.

We have proposed to use cooling coils for mushroom chambers (with 65F) & owner’s chillers can be used for that purpose. To make it more efficient, we are proposing to use “growing plant chambers” as “OA” source for mushroom chambers. It means for mushroom chambers, OA temperature will always be 85F.

My problem is how to create this secondary loop for mushroom chambers where I can assign growing plant chambers as OA source. Any “work around” for that? I am not able to assign a zone in Openstudio airloop’s supply side. Please look at PDF if it makes more sense to you.

Thank you, and looking forward for your response. Best,