Hi All,
One of my students is trying to model a ground source VRF system, and for some reason, the VRF system stops conditioning the space after April. I looked through the schedules and controls, etc and cannot find a reason for this.
I am attaching the model for your reference, and appreciate any insight in what is causing this to happen.
Thanks, Al
I've run a test with the model and what's happening is that the temperature of the geothermal wells (Ground Heat Exchanger Average Fluid Temperature of OS:GroundHeatExchanger:Vertical) is exceeding the Maximum Outdoor Temperature in Cooling Mode you've set for the OS:AirConditioner:VariableRefrigerantFlow (that is set to 43ºC).
When this temperature condition happens the system shuts down (as expected); testing it with a temperature of 80ºC (which doesn't make any sense) and using Barcelona EPW climate the system works all year round.
In any case the problem (at least) is with the sizing of the required dissipation of the ground heat exchangers, which are currently undersized (for example in Barcelona it can climb up to 78ºC in August...). I hope this is useful.
Maximum Outdoor Temperature in Cooling Mode = 43ºC
Maximum Outdoor Temperature in Cooling Mode = 80ºC
Asked: 2026-02-26 00:35:55 -0500
Seen: 334 times
Last updated: yesterday
... link to the OpenStudio model?
Ah, my apologies. I thought I could attach it to the question and it did not go through,
Please use https://drive.google.com/file/d/1geih...