In the article Martin talks about some of the modifications he made to the Earthship Biotecture global model design and why. These are worth noting as the Adelaide climate (climate zone 6- mild temperate) is much closer to NZ conditions than New Mexico. Like in Adelaide, in the north of north island we often also suffer from very warm nights and have overcast winters. Some of design modifications made in the Ironbank earthship are as follows:
- Increased area of north facing roof to accommodate more solar panels since there isn’t as much abundant winter sun as in New Mexico
- Operable skylights in greenhouse roof instead of Mike Reynolds roof vent boxes – for ventilation and also for letting winter sun deep into the rooms to warm the thermal mass
- Using PVC instead of steel cooling tubes. Martin goes into a bit of depth about the best diameter, length and depth of these to optimise heat exchange to suit both the summer and winter needs.
- Backup heating for prolonged overcast winter weather
This project is worth following as the building is wired up to collect thermal data to see how the building performs. Energy modelling calculated that it would achieve a 6.3 star rating but Martin reckons in reality it will perform more like 9 or 10 stars so that’s what he’s set out to prove. There is very little scientific data on earthship performance in temperate climates so this data will be extremely interesting to see.
The build cost worked out at approx. $2000 per square meter which is comparable to what Mike Reynolds quotes for the global model earthship design.
To find out more about the Ironbank earthship see http://www.earthshipironbank.com.au/