No answers. OK. I tested with a simple model: an adiabatic cube with hourly increasing plug load. Chiller Minimum Unloading Ratio was changed to 0.25 to clarify its impact.

• Chiller no.1: 500RT
• Chiller no.2: 1000RT
• Chiller no.3: 1000RT
• Chiller Sqeuence: Chiller no.1, Chiller mo.2, Chiller no.3
• Minimum Part Load Ratio for all chillers: 0.1
• Maximum Part Load Ratio for all chillers: 1.0
• Optimum Part Load Ratio for all chillers: 0.75
• Minimum Unloading Ratio for all chillers: 0.25

The evaporator cooling rate of Chiller no.1 did not explicitly decrease when Chiller no.2 turned ON. I revised my graphs as follows. To be precise, "false load" is not included in Chiller Evaporator Cooling Rate, but it affects Chiller Electric Power. If Minimum Unloading Ratio is the same as Minimum Part Load Ratio, chillers do not have false loading.