Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Unless you are hardsizing equipment, equipment sizing is based of the sizing run which uses the design days (.ddy files). If your .epw file has more extreme conditions, the equipment may not have enough capacity to meet the full load, depending on the oversizing factor.
I recommend sizing based off of the ASHRAE climate design conditions. If you are using TMY3 files, the bundled .ddy files use the 2009 values. I recommend the 2017 values, which you can find at the link above. You can choose a more stringent sizing criteria (e.g. 0.4% instead of 1%) or use the "extreme annual design conditions".
| | 2 | No.2 Revision |
Unless you are hardsizing equipment, equipment sizing is based of the sizing run which uses the design days (.ddy files). The TYPICAL/EXTREME PERIODS field is ignored in the simulation. If your .epw file has more extreme conditions, the equipment may not have enough capacity to meet the full load, depending on the oversizing factor.
I recommend sizing based off of the ASHRAE climate design conditions. If you are using TMY3 files, the bundled .ddy files use the 2009 values. I recommend the 2017 values, which you can find at the link above. You can choose a more stringent sizing criteria (e.g. 0.4% instead of 1%) or use the "extreme annual design conditions".
