I want a site with constant temperature and 0 solar radiation how to edit weather files

edit

This question has come up often in previous posts.

You can use the free program Elements to adjust weather files.

For your specific application, it seems like it would be easier to just set all of your exterior surfaces to "ground" adjacency, and then specify a ground temperature (changing one number in the .epw file).
If you want to specify the surface heat transfer properties in more detail, see the response to this question.

The other approach could be to use EMS (also supported by DesignBuilder) in order to override weather parameters instead of changing a weather file. Choose environment-related actuators for outdoor dry bulb temperature and solar radiation (direct and diffuse) and change their values at the beginning of each timestep. The attached example changes direct and diffuse solar radiation to 0 and sets the outdoor dry bulb temperature to 18C.

! Weather file outdoor air dry bulb temperature
EnergyManagementSystem:Actuator,
    oDBT,               !- Name
    Environment,             !- Actuated Component Unique Name
    Weather Data,            !- Actuated Component Type
    Outdoor Dry Bulb;              !- Actuated Component Control Type

! Weather file diffuse solar radiation
EnergyManagementSystem:Actuator,
    oDifSolar,               !- Name
    Environment,             !- Actuated Component Unique Name
    Weather Data,            !- Actuated Component Type
    Diffuse Solar;              !- Actuated Component Control Type

! Weather file direct solar radiation
EnergyManagementSystem:Actuator,
    oDirSolar,               !- Name
    Environment,             !- Actuated Component Unique Name
    Weather Data,            !- Actuated Component Type
    Direct Solar;              !- Actuated Component Control Type

! EMS program calling point
EnergyManagementSystem:ProgramCallingManager,
    OverrideWeatherData,       !- Name
    BeginTimestepBeforePredictor,  !- EnergyPlus Model Calling Point
    OverrideProg;           !- Program Name 1

!EMS program which sets selected weather parameters to 0
EnergyManagementSystem:Program,
    OverrideProg,           !- Name
    SET oDBT = 18,
    SET oDifSolar = 0,
    SET oDirSolar = 0;