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How to design a water based evaporative HVAC system in Designbuilder/Openstudio?

asked 2017-02-25 11:42:08 -0500

kumar.biswajit gravatar image

updated 2017-02-25 11:51:41 -0500

I need to use Designbuilder/Openstudio to design a model for a seawater greenhouse as part of a project. Here is a page which roughly shows what I would like to model: I would like to use this model to measure the humidity in the greenhouse, as well as the temperature among other things.

Thank you.

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answered 2017-02-27 21:42:52 -0500

Make an AirLoopHVAC, set it to 100% OA. Add a EvaporativeCoolerDirectResearchSpecial to represent the porous & wet cardboard, and add a fan to move the air. This approach does not include the modeling of condensing freshwater that is shown in the diagram you referenced. Here is a the layout:

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I bet you could model the condenser with a Coil:Cooling:Water (attached to a loop with district cooling source set to approximate the cooling capacity/flow rate of incoming seawater) on the exhaust air node of the OutdoorAirSystem, and output HVAC,Sum,Cooling Coil Condensate Volume [m3].

Eric Ringold gravatar image Eric Ringold  ( 2017-02-28 10:19:06 -0500 )edit

Not sure a water coil in exhaust stream of OA system will work since the coil model needs to be "called" somehow and that is usually accomplished by including the component in the OA Sys equipment list, except in this case the coil air node names would not match up with the OA components in the supply air stream. Maybe there is no test for OA Sys air node names and this might work?

rraustad gravatar image rraustad  ( 2017-02-28 10:43:47 -0500 )edit

@rraustad thanks, I admittedly didn't really consider limitations with control. I wonder (since the air loop is 100% OA) if it might be more feasible with the water coil on the return side of the air loop instead of the OA system. Or, I suppose if the user is interested in the amount of condensate available in the air leaving the greenhouse there would be ways of post-processing that using air temp/humidity/flow outputs.

Eric Ringold gravatar image Eric Ringold  ( 2017-02-28 11:07:15 -0500 )edit

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Asked: 2017-02-25 11:42:08 -0500

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Last updated: Feb 27 '17