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# Point of Use Electrical Hot Water Heater

What is the best way to model a Point of Use Electrical Hot Water Heater in OpenStudio?

I was thinking that I could setup several small electric hot water heaters with small water volumes and let them address the demand. Would this be appropriate or might there be a better solution?

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I'd do it the same way. You can directly assign a "Use Flow Rate Fraction Schedule" use to a WaterHeater:Mixed object without the need for a plant loop.

The I/O examples here actually list one that is pretty close to your needs, the one named "Stand-alone electric, tankless example", except you could change the "Ambient Temperature Indicator" to Zone and hook up your thermal zone to it, and it'll look like this:

WaterHeater:Mixed,                     ! Stand-alone electric, tankless example
Tankless,  !- Name
0.003785,  !- Tank Volume {m3}
Hot Water Setpoint Temp Schedule,  !- Setpoint Temperature Schedule
,  !- Deadband Temperature Difference {deltaC}
82.2222,  !- Maximum Temperature Limit {C}
Modulate,  !- Heater Control Type {Cycle | Modulate}
11712,  !- Heater Maximum Capacity {W}
0,  !- Heater Minimum Capacity {W}
,  !- Heater Ignition Minimum Flow Rate {m3/s}
,  !- Heater Ignition Delay {s}
ELECTRICITY,  !- Heater Fuel Type
0.95,  !- Heater Thermal Efficiency
,  !- Part Load Factor Curve
10,  !- Off-Cycle Parasitic Fuel Consumption Rate {W}
ELECTRICITY,  !- Off-Cycle Parasitic Fuel Type
0,  !- Off-Cycle Parasitic Heat Fraction To Tank
30,  !- On-Cycle Parasitic Fuel Consumption Rate {W}
ELECTRICITY,  !- On-Cycle Parasitic Fuel Type
0,  !- On-Cycle Parasitic Heat Fraction To Tank
Zone,  !- Ambient Temperature Indicator {Schedule | Zone | Outdoors}
,  !- Ambient Temperature Schedule
<INSERT NAME OF THERMAL ZONE>,  !- Ambient Temperature Zone
,  !- Off-Cycle Loss Coefficient To Ambient Temperature {W/K}
,  !- Off-Cycle Loss Fraction To Zone
,  !- On-Cycle Loss Coefficient To Ambient Temperature {W/K}
,  !- On-Cycle Loss Fraction To Zone
0.000379,  !- Peak Volumetric Use Flow Rate {m3/s}
Hot Water Demand Schedule,  !- Use Flow Rate Fraction Schedule
;  !- Cold Water Supply Temperature Schedule


Of course, do change both the "Peak Volumetric Use Flow Rate" and "Use Flow Rate Fraction Schedule" to match your actual case.

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