I'm trying to model a DHW system in Openstudio, and the simulation report is showing an energy expenditure that only makes sense if the water heater is on-cycle 24 hours a day. I've double checked that hot water temp is below the heater maximum temp, and I don't know what else could be happening. Is there a way to manually define cycle fraction for a hot water heater, or is it all handled autonomously?

The only clue I have to this problem is this message in the eplusout file:

** Warning * ** CalcEquipmentFlowRates: "COMMUNAL WATER EQUIPMENT" - Target water temperature is greater than the hot water temperature (28.55 C)
 
*   ~~~   * C)
**   ~~~   **  Environment=MIRAMICHI ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 00:00 - 00:10
 
*   ~~~   * 00:10
**   ~~~   ** ...target water temperature       = 43.33 C
 
*   ~~~   * C
**   ~~~   ** ...hot water temperature       = 14.78 C
 
*   ~~~   * C
**   ~~~   ** ...Note: target water temperature should be less than or equal to the hot water temperature
 
*   ~~~   * temperature
**   ~~~   ** ...Target water temperature should be less than or equal to the hot water temperature. Verify temperature setpoints and schedules.
 
EDIT: I may have solved the problem, I had assumed temperature setpoints used metric or imperial depending on the program settings (I have it set to imperial currently), but apparently they are always in Celsius?  Using a Celsius value produces much more sane results.schedules.

I'm trying to model a DHW system in Openstudio, and the simulation report is showing an energy expenditure that only makes sense if the water heater is on-cycle 24 hours a day. I've double checked that hot water temp is below the heater maximum temp, and I don't know what else could be happening. Is there a way to manually define cycle fraction for a hot water heater, or is it all handled autonomously?

The only clue I have to this problem is this message in the eplusout file:

** 
* Warning ** * CalcEquipmentFlowRates: "COMMUNAL WATER EQUIPMENT" - Target water temperature is greater than the hot water temperature (28.55 C)
**   ~~~   ** C)
 
*   ~~~   *  Environment=MIRAMICHI ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 00:00 - 00:10
**   ~~~   ** 00:10
 
*   ~~~   * ...target water temperature       = 43.33 C
**   ~~~   ** C
 
*   ~~~   * ...hot water temperature       = 14.78 C
**   ~~~   ** C
 
*   ~~~   * ...Note: target water temperature should be less than or equal to the hot water temperature
**   ~~~   ** temperature
 
*   ~~~   * ...Target water temperature should be less than or equal to the hot water temperature. Verify temperature setpoints and schedules.

I'm trying to model a DHW system in Openstudio, and the simulation report is showing an energy expenditure that only makes sense if the water heater is on-cycle 24 hours a day. I've double checked that hot water temp is below the heater maximum temp, and I don't know what else could be happening. Is there a way to manually define cycle fraction for a hot water heater, or is it all handled autonomously?

The only clue I have to this problem is this message in the eplusout file:

* Warning * CalcEquipmentFlowRates: "COMMUNAL WATER EQUIPMENT" - Target water temperature is greater than the hot water temperature (28.55 C)

* ~~~ * Environment=MIRAMICHI ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 00:00 - 00:10

* ~~~ * ...target water temperature = 43.33 C

* ~~~ * ...hot water temperature = 14.78 C

* ~~~ * ...Note: target water temperature should be less than or equal to the hot water temperature

* ~~~ * ...Target water temperature should be less than or equal to the hot water temperature. Verify temperature setpoints and schedules.