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I was only using a target temperature schedule - adding a latent fraction schedule does result in higher RH values for those zones. Worked great, thank you!!

I am modeling an indoor agriculture facility using OpenStudio 1.14.0. I started with a simple model using ideal air loads, which returned results that I'd expect considering sensible loads only.

The next layer of this model is to simulate the watering schedule within the facility, as this contributes to the high RH values seen in facilities like this and thus to the need for dehumidification/cooling. My thoughts for approximating this was to set up a service hot water loop with fixtures and schedules that would be representative of the amount of water the agriculture typically receives throughout a day.

The model ran successfully with the service hot water loop; however, the humidity table values for each zone stayed the same as compared with the model with no service hot water loop. Changing the number of fixtures, equipment schedules, and flow rates also have no impact on RH, but do impact energy use.

So, two questions:

1) Is there ever a case where using a service hot water loop would impact zone RH? If you have a single zone with a bunch of showers in it running frequently (locker room, for example), I'd expect the mean RH to be reported as higher for that zone than for zones without showers. Am I missing something with this approach?

2) Is there an alternate method for adding humidity to a space that I should explore? I had initially wanted to avoid adding any humidifying equipment directly since this would artificially contribute to the net site energy. This approach would essentially have humidifiers on a high RH setpoint, competing with dehumidifiers on a lower RH setpoint...seems like a weird way of going about it.

This works too, thank you! As I also mentioned above, I ended up trying the method (which also works) of drawing a rectangle in each vertical exterior face of the atrium, and in my particular case offsetting the rectangle by 6" from each side of the surface. So it's something like a .99 WWR. Then 'project all loose geometry'. The last thing was once in OpenStudio, I did have to specify the construction for the horizontal ceiling portion (automatically denoted as a "Skylight"). I set this to ExtWindow; model ran great with results as expected.

Yup, this worked! Plus the link was very helpful just in general - thank you.

Other things I have tried:

Creating a new Construction with a custom Material with properties of glass. However, this gives opposite thermal results to what I would expect when using the View Data measure (atrium is cooler than the rest of the building during the peak of summer).

Creating a new Construction with 'Theoretical Glass' as the material, picked from the list of default glazing window materials. This fails because I've used a non-wall material to define a wall.

I am trying to model an atrium in Open Studio. Since it is not possible to set a window-to-wall ratio of 1 in Sketchup, I was told to specify the building material as glass in the Open Studio application. However, when I do this (in the Spaces --> Surfaces tab), the model fails because the Surface Type is still defined as a Wall. The only options I have for Surface Type are Floor, Wall, or RoofCeiling.

I have tried leaving the Construction Set for the surface in question as the default ExtWall, and specifying the material as glass. This fails; error being that glass is not an acceptable material for a Wall surface type. I have tried changing the Construction Set to ExtWindow, but this also fails as the surface type is still set to Wall.

Any suggestions would be greatly appreciated!

This solved the problem - very simple. Thank you!

Hello! I am playing around with a simple building model in Open Studio. The simulation ran with no errors until I tried to add an HVAC system. I added a PTHP (Packaged Terminal Heat Pump) system to Thermal Zone 1. Ideal air loads are thus turned off for this zone. The remaining four thermal zones operate with ideal air loads only.

I get the following severe error which causes the simulation to fail:

* Severe * For autosizing of ZoneHVAC:PackagedTerminalHeatPump PTHP, a zone sizing run must be done. * ~~~ * No "Sizing:Zone" objects were entered.

What I have tried, per other thread posts: Under Simulation Settings --> Simulation Control, I have turned on "Do Zone Sizing Calculation", "Do System Sizing Calculation", and "Do Plant Sizing Calculation"

Any idea how I can add a zone sizing object/fix this error?