Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I exported my simulation in OpenStudio to an IDF file so I could work in EnergyPlus. I am using a Pump:VariableSpeed object to circulate water from the solar collectors to a storage tank (WaterHeater:Mixed with a heater capacity of 0). In EnergyPlus you can specify a pump flow rate schedule. I created a fractional schedule where the pump was off (value = 0) from 0:00 to 10:00, then on (value = 1) until 16:00, and then off again until 24:00. This fixed the collector efficiency, and collector heat transfer energy. Now the efficiency is mostly positive (some negative values in middle of winter) and the heat transfer energy has a minimum value of zero for most days throughout the year, with a few exceptions. Playing around with the times in the fractional schedule should clear up any remaining negative values.
