Yasin Khan,
The values to use in the Site:GroundTemperature:BuildingSurface object depends on whether the indoor of your building is conditioned, to a certain temperature, or not conditioned, ie. free running building?
If the indoors is conditioned with an HVAC or, in EnergyPlus simulation, an "IdealLoads" system, then you need to use the Slab or Basement Utility/Preprocessor, to obtain the 12 monthly values. In recent versions of EnergyPlus, you can also just enter your conditioned temperature into the respective objects in the idf.
If the indoors is not conditioned, then a good approximation for the 12 monthly values in the Site:GroundTemperature:BuildingSurface,,especially for buildings with a floor that is not too large, is to use the 12 values in the Stat file. For Concrete slab on ground, the values at 0.5m deep may do, i suppose.
It is possible to enter (8760) hourly values for a whole year for an EnergyPlus simulation. You need to create a txt file. Details are given in the Documentation
The value given int eh Stat file are based on a standard diffusivity. This is significantly influenced by the moisture and type of soil,
ooi
On Tue, Nov 12, 2013 at 7:33 AM, Edwin Lee <leeed2001@...> wrote:I'm guessing you are saying that your DesignBuilder model used the default of 18 degrees for all year for the ground temperature. You can enter monthly measured or assumed values in the Site:GroundTemperature:BuildingSurface object. You can get a better approximation of these values if you use the CalcSoilSurfTemp utility.--On Tue, Nov 12, 2013 at 7:26 AM, yasin khan <yasinkhan683@...> wrote:
hello everyonei am facing a problem in defining in ground temperature because when i export idf file from design builder in takes 18 degree C for all the 12 months as default value for my climate condition. however i change this value by monthly dry bulb temperature i don't know that this methodology is correct or not. So plz can anybody can tell me that i am doing the right thing or not and tell me the better way for ground temperature.
Edwin Lee, PhDEngineer, Commercial Buildings Research StaffNational Renewable Energy Laboratory--Edwin Lee, PhDEngineer, Commercial Buildings Research StaffNational Renewable Energy Laboratory