Unrealistic service water heating load
I'm currently using Openstudio 1.14 on a windows 10 computer. I'm having problems with the service water heating load- when I follow the OS 0.9 online tutorial instructions for adding fixtures and a service water loop, I get absurdly high natural gas loads for the water heater (almost half the building energy load for two 'bathrooms' with 4 fixtures each- but online sources say service water load for my type of building should only be 5-10% of building energy use). Does anyone have any idea why this might be happening? If I try to auto-size the tank volume or service water heater capacity the simulation has a 'fatal error' and fails- that's the only thing I've tried so far.
Assuming you have the max flow rate for the fixture, also look at the flow rate fractional schedule. This should typically be much lower than the fractional usage schedule for lights or equipment.
This is at least part of the story- I just drew the fractional schedules down and got a significant change.
Can't help more without information on what the WaterHeater Mixed object looks like. An unlikely culprit would be unusually cold water coming into the system, or a pump that is using too much energy.
Thanks, I think it was the flow rate of the fixtures (now @ the 'baseline' levels specified in the LEEDv4 reference), the fractional use schedule, and the temperature (now set to a more 'moderate' temperature for hand-washing).