When we use HVAC:Template:Plant:Tower or HVAC:Template:Plant:Tower:ObjectReference, the expidf file automatically sets condenser water temperature reset control by SetpointManager:FollowOutdoorAirTemperature as follows:
SetpointManager:FollowOutdoorAirTemperature,
CHWloop CndW Temp Manager, !- Name
Temperature, !- Control Variable
OutdoorAirWetBulb, !- Reference Temperature Type
0, !- Offset Temperature Difference
80, !- Maximum Setpoint Temperature {C}
5, !- Minimum Setpoint Temperature {C}
CHWloop CndW Supply Setpoint Nodes; !- Setpoint Node or NodeList Name
I think Offset Temperature Difference can be regarded as "Approach" of cooling tower. It's set to 0°C, which is unachievable in principle. A quite large range of Minimum Setpoint Temperature and Maximum Setpoint Temperature is also unnatural.
As @Lincoln and @Julien Marrec mentioned in this post, cooling tower is controlled to deliver an unachievable approach of 0°C, and therefore we get high fan energy consumption. When I use HVACTemplate, I always edit expidf file to change this SetpointManager:FollowOutdoorAirTemperature setting.
Is there any reasonable reason why Offset Temperature Difference is set to 0°C by default? I may have overlooked something.
