Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
At first, as long as I know, we can't model variable condenser flow in EnergyPlus. Please refer to this post. I also wanted to compare constant flow and variable flow, but I couldn't.
In my experience as a MEP engineer, I have designed both constant condenser water flow (variable fan speed) and variable condenser water flow (constant fan speed), but in both cases, the plant system is not the packaged water source units but absorption chillers. It is best to ask the manufacturer of the packaged water source units. For some packaged water source units, the range of condenser water flow rate is limited such as 80% to 120% of the rated flow rate.
There are various factors involved in the energy saving of the whole plant system, so it is not clear which scenario saves more energy, but in your variable flow system with primary and secondary loops, primary loop is constant and adding plate-type heat exchanger increases pump head, which sounds disadvantageous.
