Australian Passive Solar Home

Well, I think the data logging system of our passive solar house is finally nearly finished! So what does the system measure and log?

First it measures temperatures: in most of the rooms at shoulder height, and in the two large rooms with raked ceilings, additionally at the apex of each ceiling.

It also measures the temperature outside, and multiple temperatures of the concrete slab – the main thermal mass.

In addition, the temperature of the two internal 2000 litre water tanks (more thermal mass) are also measured.

The system also measures radiant temperature in one room.

The system measures outside sunshine intensity and wind speed.

Flow through the roof ventilator is also measured (when the ceiling hatches are open, this forms part of the house convectional ventilation system). The temperature of the air in the roof space near the ventilator is measured.

Inside carbon dioxide is measured, as is relative humidity – two late additions. Dew point is calculated from air temperature and relative humidity.

Including calculated parameters, there are 23 channels of logging.

The aim of the system is four-fold.

First, to better operate the house. If you can see how the house is behaving (e.g. the temperature of the thermal masses), then you can better know when to (say) open the house at night to cool the interior.

Second, I wanted good data for my book on passive solar design, where the house is the primary example.

Third, I wanted the data so that I could see how closely the actual house performance matches the NatHERS software modelling.

And finally, seeing all the information is fun!

PS: And what do I now think should be measured in all passive solar houses? Interior air temp, outside air temp and the temp of the main thermal mass.