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EnergyPlus WaterHeater Error: Target water temperature less than hot water temperature

asked 2023-08-18 21:56:02 -0500

updated 2023-08-19 08:40:56 -0500


I was wondering if anyone could help me with the following EnergyPlus question. More specifically, I'm modeling a water heater object for a single-family model (WaterHeater:Mixed). While the model ran successfully, I found the following error, that has repeated for each fixture:

Target water temperature should be less than or equal to the hot water temperature error continues... * ~~~ * water temperature = 48.89 C * ~~~ * water temperature = 47.58 C

I tried to resolve that error by applying the following potential resolutions, but non of them worked:

  1. Incresed DHW loop setpoint temperature using SetpointManager:Scheduled
  2. Increased Water Heater Maximum Temperature Limit

Any suggestions will be greatly appreciated!

Thanks, Mohammad

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shorowit's avatar shorowit  ( 2023-08-19 07:49:47 -0500 )edit

@shorowit Thanks Scott. I already reviewed that question. As I tried to explain in my question, changing the setpoint manager schedule in the plant loop did not resolve those warnings. Any further suggestions will be greatly appreciated!

Mohammad's avatar Mohammad  ( 2023-08-19 09:32:18 -0500 )edit

It probably is a sizing problem. Your water heater is not capable of providing the required energy to heat the water. Try to increase its capacity or reduce the peak flow rate of your water equipment and see if that works

Petros Dalavouras's avatar Petros Dalavouras  ( 2023-08-23 13:01:32 -0500 )edit

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answered 2023-08-23 09:33:47 -0500

I believe the warning is saying that the WaterUse:Equipment's target temperature input is greater than its hot water temperature input. Look at the documentation for these two fields:

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Asked: 2023-08-18 21:56:02 -0500

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Last updated: Oct 11 '23