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Cooling load spikes while testing pre-cool using DoE Prototype High-rise Apartment

asked 2024-09-23 10:19:38 -0500

Yapan's avatar

updated 2024-09-23 14:25:26 -0500

Hello,

I am using the DoE High-Rise Apartment Prototype building model to test a pre-cooling strategy and explore how much load can be shifted. I have access to whole-building master meter data from a real-life, older multifamily building. My goal is to calibrate the DoE model with this measured data and then test a pre-cool thermostat setpoint control (single cooling). Below is the schedule I implemented in the simulation.

SCHEDULE:COMPACT,
PRECLG_CLGSETP_APT_SCH,    !- Name
Temperature,              !- Schedule Type Limits Name
THROUGH: 12/31,           !- Field 1
For: Weekday SummerDesignDay,    !- Field 2
Until: 13:00,             !- Field 3
23.89,                    !- Field 4
Until: 15:00,             !- Field 5
22.22,                    !- Field 6
Until: 19:00,             !- Field 7
25.56,                    !- Field 8
Until: 24:00,             !- Field 9
23.89,                    !- Field 10
For: Weekend AllOtherDays,    !- Field 11
UNTIL: 24:00,             !- Field 12
23.89;                    !- Field 13

However, I am having a problem. The HVAC system meter output shows significant spikes at 15:00 when pre-cooling starts and at 19:00 when the ride-through period ends. In the actual building, the maximum chiller electrical load is around 220 kW with COP around 6.5. Although I have limited the chiller capacity in the IDF file, I would prefer that the zone temperature not meeting the pre-cooling setpoint rather than surpass the chiller's capacity.

Below is a screenshot of the simulation results.
image description

I have tried to limit the following parameters regarding HVAC system capacity:

Coil:Cooling:WaterToAirHeatPump:EquationFit
!- Gross Rated Total Cooling Capacity
!- Gross Rated Sensible Cooling Capacity

PlantEquipmentOperation:CoolingLoad,
    WSHPPlant Cool Operation Scheme,    !- Name
    !- Load Range 1 Lower Limit
    !- Load Range 1 Upper Limit
    WSHPPlant Cooling Equipment;    !- Range 1 Equipment List Name

EvaporativeFluidCooler:SingleSpeed,
    Central Tower,            !- Name
    !- Standard Design Capacity

I would appreciate any insights or suggestions on how to resolve this issue. Specifically, how can I avoid such large spikes in load while maintaining reasonable zone temperatures without exceeding the chiller capacity?

Thank you! I appreciate your time.

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answered 2024-09-23 17:00:28 -0500

Yapan's avatar

I've figured this out by limiting the supply fan air flow rate. Please see below parameter:

Fan:OnOff,
AirLoop G SW Supply Fan,    !- Name
autosize,                 !- Maximum Flow Rate
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Asked: 2024-09-23 10:19:38 -0500

Seen: 49 times

Last updated: Sep 25