Australian Passive Solar Home

I recently added a black bulb wall temperature sensor to my passive solar house, in construction north of Canberra. Unlike a normal temperature sensor, a black bulb sensor measures radiative heat exchange. It does this by sensing the temperature of the air within a black metal dome, the dome heated or cooled by radiative heat transfer.

Radiative heat transfer is very important to human comfort. If for example the walls or floors are cool, but the air temp is warm, the body will feel cooler than the air temp suggests. It is radiative heat exchange that mostly explains why some houses feel colder or warmer than the air temperature suggests.

I can already see in my logging that the black bulb temperature, despite always being shaded, varies with sunshine passing through a window.