Hello all,
I am creating a Honeybee model for a commercial project but I’m having trouble getting accurate hot water usage estimates. Using the HB SHW System and assigning hot water loads to two restrooms and a utility closet with the HB ServiceHotWater component is yielding a water heater with a very small (0.0016 m³) tank within the EnergyPlus simulation (I can see this in the .idf file).
From the warnings in the HB ModelToOSM report I can see this results in inaccurate hot water calculations and presumably the EUI related to hot water is inaccurate. Here are the main warnings:
Warning: CalcEquipmentFlowRates: “SERVICEHOTWATER_FF9DE2C5…RESTROOMS_2_B271762E” - Hot water temperature is less than the cold water temperature by (8.82 C)
Environment=RUN PERIOD 1, at Simulation time=01/01 00:00 - 01:00
…hot water temperature = 2.46 C
…cold water temperature = 11.28 C
…Hot water temperature should be greater than or equal to the cold water temperature. Verify temperature setpoints and schedules.
Warning: WaterHeater:Mixed = SHW WATERHEATER: Heater is cycling on and off more than once per second.
Try increasing Deadband Temperature Difference or Tank Volume
Environment=RUN PERIOD 1, at Simulation time=01/01 00:00 - 01:00
I’m not sure if this is a bug in Honeybee or if my inputs are wrong somehow, but either way I’m looking for any tips on how to get an accurate water heater tank size in the EnergyPlus sim since it cannot be manually specified with Honeybee components.
I appreciate the help