nedeľa, 9. januára 2011

Moisture Levels

I wish you all a HAPPY New Year!

Here are the latest humidity measurements from august to december 2010 - unfortunately the batteries in the logger lost power the day we left... so I have no measurements from 19.12. to 9.1.2011.

I reduced the number of loggers in the graph to make it more readable. The orange line is the logger in the middle of the straw bales in the dome, the purple one is a logger in the foam glass (about 20cm in from the outside, in a valley). The grey and black lines are outside and inside temperature and relative humidity measurements.

What I think is interesting:

- The humidity levels increased during autumn in the straw bales, although the dome was covered against rain and wind could dry the plaster.

- Ventilation with heat recovery did lower the humidity inside, but because we put on heating at the same time, the humidity levels increased slightly in the beginning.

- After getting the moisture level below 65% inside, the humidity in the bales started dropping as well. This has continued until today, the last measurements shows 68% Relative Humidity in the middle of the straw.

- The moisture levels in the Foam glass is also dropping, very slowly and the drop started later. Also other sensors show a similar behavior. All sensor in the outer areas (cold areas) show relative humidity levels above 90%.

For the moment I think the straw bales are OK, what is happening in the last 5cm below the EPDM we don't know. Guess the clay absorbs any excessive moisture.

As for the inside temperature: we have had the heating on continuously in december and january, and the temperature inside stays around 20°C as long as the outside temperature does not drop below zero. We have no good door yet (just 6mm plywood) and one window is broken. And we are removing a lot of moisture, and that is rather energy demanding.

I guess with the door in and when we get some computers and people in, we will be fine even at -10°C. The inside temperature dropped to a minimum 17,6°C, never lower.