Knowledgebase
Why do I get different CoP values and fuels in the idf to those entered in DesignBuilder HVAC tab?
Posted by Andy Tindale on 02-Nov-16 09:57 AM

DesignBuilder does not use the fuel consumption values generated by EnergyPlus but instead calculates fuel consumption from coil loads and the ideal system loads used in Simple HVAC using heating and cooling CoP values entered on the DesignBuilder HVAC tab.

The fuel and efficiency parameters that are included in the IDF file generated by DesignBuilder are pre-canned fixed values but they are used by E+ when it calculates it's fuel consumption so the energy consumption results reported by EnergyPlus will be incorrect given the requested CoP values.

If you need to work with IDF and run simulations outside DesignBuilder then you'll need to edit the CoP values and fuel settings  in the IDF file to obtain correct results.

Future versions of DesignBuilder will use EnergyPlus fuel consumptions, but until then the fuel consumptions reported by DB and E+ will differ.

See also:

https://www.designbuilder.co.uk/helpv5.0/#When_DesignBuilder_output_is_different_from_unprocessed_EnergyPlus_Output.htm


Updated 02.Nov.2016