What does Summer condition day mean? Can I use a summer condition day weather profile to do a simulation representing a whole summer?

edit

EnergyPlus lets you enter a RunPeriod object (link) which defines the period of simulation. If you are only interested in a specific period (for example summer design day) you can set the RunPeriod to that.

You may also want to run for a longer period to show the effect of a longer period of hot weather. A good start might be the extreme summer week which you can find at the bottom of the .stat file for your location. Here's an example from Gatwick, UK.

 - Typical/Extreme Period Determination

 - Summer is Jun:Aug
       Extreme Summer Week (nearest maximum temperature for summer)
       Extreme Hot Week Period selected: Aug 17:Aug 23, Maximum Temp=  31.30°C, Deviation=|12.677|°C
       Typical Summer Week (nearest average temperature for summer)
       Typical Week Period selected: Jun 29:Jul  5, Average Temp=  16.36°C, Deviation=| 0.115|°C

The typical summer week will give you typical performance (closest to the average summer temperatures in the EPW) while the extreme summer week (covering the maximum temperature in the EPW) will give you the system performance under the greatest stress. Which you choose depends on what you're trying to find out.

Depending on where you got your weather file (.epw), you may find the .stat file in the same place. If you can't find it then you can use the WeatherConverter program that ships with EnergyPlus to generate it. It should be in the EnergyPlusV8-3-0\PreProcess\WeatherConverter directory. Select your EPW, set the output to "Statistics report on input file", tell it where to save it, and then hit convert.

In open studio you can chose to run a period of the year instead of the entire year.