EnergyPlus has added the Large Data Center BuildingType which is accessible via the Pollination Revit Plugin. See the [link]
The HVAC Layout for large data centers typically is a Computer Room Air handling Unit with Central Chille/
Im pretty new to energy modeling so I am wondering how to implement the CRAH HVAC layout via a pollination recipe or honeybee grasshopper script.
Doesn’t look like the original link was posted.
here it is:
prototype_energy_models_for_data_centers.pdf (lbl.gov)
According to the paper, a new Building Type has been added to EnergyPlus to represent small and large data-center building types. This could be very useful for Data Center builders.
I can access the type in Pollination; however we are not certain to complete the energy analysis.
Hi @moses-woolpert ,
Do you have a specific question here? It seems like you have found that we provide program types with pollination that describe data centers, which were taken from the DoE prototype buildings referenced in that PDF.
Assigning those to your Rooms will give them electric equipment loads and schedules that align with those of the data center prototype model.
Is your question about which HVAC system template included in Pollination best fits the description of a “Computer Room Air handling Unit with Central Chiller”? If so, I would probably choose a Variable Air Volume (VAV) system:
… and just make sure that you choose one of the options with “chiller” in the “HVAC Equipment Types”:
If you assign a separate one of these VAV systems for each computer room, you will effectively get an OpenStudio model where each computer room has its own AHU but they are all connected to a central chilled water loop like that PDF describes. And you’ll effectively have something that satisfies practically all of the criteria for the Large Data Center described in this table taken from the PDF:
Granted, none of the template HVAC systems in Pollination have water side economizers in them so, if that’s really important to you, you would have to build your own VAV system in Ironbug. But, as the table notes, water side economizers are a relatively new requirement by the energy code and I think they might not be required in all climate zones. So I would think you could still run some studies without it and have a reasonably accurate model for making decisions about which strategies to implement.
Hello @chriswmackey ,
I saw your response so I wanted to update my question.
Yes, that was my question. How to simulate the CRAH system in Honeybee or Pollination.
Typically we have a floor of hundreds of servers (not actually computer rooms) with a an air plenum that moves the air to the chillers on the on the outside of the building.
These are hyper-scale data centers that are sometimes 100,000 sqf.
Would the solution you described still work if the situation is for a DataHall?
Thanks for clarifying, @moses-woolpert .
A lot of those details in that diagram are at a level below what EnergyPlus (or any other BEM software) typically takes into consideration. You’re right that you could try to break down the aisles into separate zones but this is probably NOT going to make the simulation more accurate since this isn’t really how the system works and you don’t have separate thermostats for the two different types of aisles. This is probably one reason why that study in the PDF did CFD simulation to validate their assumptions for E+.
Granted, E+ is still going to have separate nodes for the zone, it’s supply and it’s return, which should be good enough for estimating the energy usage of the cooling system for this case. Also, I just generated an OSM of the Large Data Center using the create_DOE_prototype_building OpenStudio Measure. I can see that, in that model, everything is organized as a single zone:
… and the CRAH is effectively the VAV template system that I pointed to but without the air side economizer and with a humidification system:
Here’s the OSM if you want to see for yourself:
So I would recommend modeling each large continuous space of the data center as a separate zone, give it a humidification setpoint of 8% (this is what I see in the prototype building OSM), and don’t use an air-side economizer for the VAV system. That should get you something that follows the prototype model pretty well.
Thanks @chriswmackey ,
I believe i understand.
For us, the datahall (containing servers, aisles, and CRAH units) would be one continuous space.
These data halls might be mid-size or larger stand-alone buildings; however, the ‘Data Center’ building type in Energy Plus accounts for those discrete factors in its model.
Just to confirm:
For the HVAC layout, I can choose the VAV System with Chiller as you described in your first post. Each Continuous Data hall Space would be its own zone that the HVAC Layout is applied to in Pollination.
Thanks!
If that is confirmed, I will give that a try.
To respond to your points, questions:
Yes, then I would model the data hall as one zone similar to the EnergyPlus Prototype building. Also, if it was not clear, that OSM file that I uploaded IS the EnergyPlus Prototype building of a Large Data Center with a high ITE.
Yes, that is correct.
Blockquote
Yes, then I would model the data hall as one zone similar to the EnergyPlus Prototype building. Also, if it was not clear, that OSM file that I uploaded IS the EnergyPlus Prototype building of a Large Data Center with a high ITE.
Yes, I opened the OSM file and saw that it was one continuous space. I will try to replicate the settings for my own project in Pollination or IronBug.
Thanks,
Moses
I watched a youtube video where @mostapha used the Pollination Rhino plugin to detect whether surfaces were out-side facing or inside facing.
‘Solving Adjacencies’ Video:
Our hyperscale data centers typically have an admin building (office prototype) that is connected to the data hall (data center prototype).
Does the Pollination Revit app have tools that help you assign adjacencies or I should do this in the Rhino app?
So far, I havent seen an example of solving adjacencies in Revit and I believe its an important part of EnergyPlus simulations.
Thanks!
Hi @moses-woolpert,
You can solve adjacency in the Revit plugin too. I suggest using the new model editor for that.
But you can also find it in step 6. You can see it after clicking on the settings gear. Choose the Full option and it will solve the adjacency between the rooms.
