Hi everyone
I would like to ask a question about Ironbug as I’m beginner. I have set up a VRF system where I would like to specify 1 TON = 3516 W of air conditioning capacity in the living room.
But when I enter the parameter, in the EnergyPlus report only the “Airconditioner:VariableRefrigerantFlow” changes, but the Coil Final Gross Total Capacity does not change. Do you know why this is happening?
I appreciate any help
Luiz
Hi @LuizHVAC
I guess you define the capacity static in your configuration 3516 as a static panel connected to the params of the VRF system (down below the picture)
If the terminal unit’s coil capacity is supposed to scale with the VRF system, confirm that the autosizing settings are enabled and that there are no hardcoded values overriding the sizing process
Using EnergyPlus for load calculations isn’t incorrect, as it can calculate peak loads (e.g., via the “Coil Sizing Summary” or “Zone Sizing” reports). However, EnergyPlus is overkill for pure load calculations because it’s designed for detailed energy and system performance simulations over time, not just peak load snapshots.
For accurate design, you may find IronBug examples in the grasshopper as HVAC Template component. It has simple and advanced VRF.
Hi, thank you for your feedback.
I understand what you meant. However, this is actually a small part of a larger and more complex study where I am using PMV calculations to evaluate thermal comfort in a large office building. In many areas of this building, there are oversized HVAC systems installed in small rooms with high internal loads. Because of this, I need to input the actual installed capacity of the air conditioning units, not the autosized one, to correctly identify the critical zones where I should strategically place thermostats.
Currently, temperature sensors are only located inside cassette units about 3 meters above the floor, and not at occupant level, which causes significant discomfort. When I run PMV simulations, the model assumes the capacity the unit should have (as per autosizing), but not the real installed capacity, which distorts the thermal comfort results.
I’ve made good progress with this analysis, but I’d like to know how to define the actual cooling capacity in the terminal unit coil. Right now, I’m only managing to override the capacity in the condenser (VRF system) by setting it to 3516 W.
I’ve checked the Ironbug HVAC templates, but didn’t find a way to specify this directly in the terminal units, only how to set the outlet air temperature (12.8°C).
Any help or guidance on how to hardcode the terminal unit coil capacity would be greatly appreciat
