Default values
Default values are used in a number of locations in BSim if nothing else is given by the user. In the following all standard values used in BSim will be shown.
Surface properties (finish)
Thermal surface resistance
If nothing else is given a fixed surface resistances for finishes facing outdoors and respectively a thermal zone is used. The default values for the surface resistances and the convective heat transfer coefficients are shown in the table below.
| Internal surface resistance | Value | Unit |
|---|---|---|
| Upward heat flow | 0.10 | m²K/W |
| Vertical heat flow | 0.13 | m²K/W |
| Downward heat flow | 0.17 | m²K/W |
| External surface resistance | Value | Unit |
|---|---|---|
| Upward heat flow | 0.04 | m²K/W |
| Vertical heat flow | 0.04 | m²K/W |
| Downward heat flow | 0.04 | m²K/W |
| Internal convective resistance | Value | Unit |
|---|---|---|
| Floors | 0.40 | m²K/W |
| Ceilings | 0.50 | m²K/W |
| Walls | 0.33 | m²K/W |
If simulation of long wave radiation (in / out) at the Options tab of tsbi5, a convective surface resistance will be calculated dynamically, dependant on the temperature difference between the surface and the air and the wind speed at the outside surfaces.
Light technical properties
If no material is selected representing the finish properties, SimLight will use the following default values for reflectance in the calculation of daylight conditions in the model:
Absorptance: 0.9
Reflectance: 0.2
Emissivity: 0.8
Room properties (temperature and moisture)
If a space is placed outside a thermal zone, given the same temperature as a real thermal zone or connected to a temperature profile, 20 °C is used as a fixed indoor temperature during the entire simulation period.
Photovoltaic panels (PV)
If no "material" is selected for areas with PV, a standard system is assumed consisting mono cristalline silicon cells, a good electrical layout and a proper AC/DC inverter. The default values for this are:
| Variable | Value |
|---|---|
| System efficiency | 8,12 %. |
| Shaded part efficiency | 15 %. |
| Proportional shading reduction | No. |
Photovoltaic panels can be calculated by a module in BSim.