We’ve encountered an issue regarding the cooling coil. We did a sensitivity analysis on the cooling coil to compare the energy consumption with a validated program. We fixed the energy demand and increased the size of the cooling coil. To my surprise, the energy consumption keeps increasing.
In my opinion, for a fixed cooling demand, the energy consumption should not increase with increased cooling capacity. Do you agree?
We’re simulating an AHU with CAV and a constant blow in temperature of 20 degrees. So the only purpose of the AHU is to condition the outside air to 20 degrees without any heat recovery or feedback loops.
This is a very simplified assumption. If you think about using an “over-sized” commercial system in a small residential room, what would think the result will be? Whenever a small demand occurs, the big system will turn on all parts and run at full capacity or run all the time if the control is not “smart”.
I would guess this CAV might affect your system running correctly at every timestep. You can try to look at the hourly output data (flow, power, energy) for each component (coil, fan) to ensure they perform as expected.
How do you get the energy consumption? is it from the Energyplus’s output html table or do you manually add up all hourly energy usage? Based on what you are doing, it is better to calculate them manually just to be sure you are looking at the correct data.
