Welcome to the second installment from First Light, the Kiwi team from Wellington’s Victoria University competing on the world stage in the US Department of Energy’s 2011 Solar Decathlon competition. The challenge has literally heated up for the team as they’re tasked with marrying passive solar features for their 'Kiwi bach' with strict competition rules.
We entered into this competition knowing it would be a challenge; however we did not anticipate just how greatly the differences in culture and lifestyle between New Zealand and the US would affect our entry.
Our aim has always been to take the Kiwi lifestyle to the world—Kiwi’s like to live simply and live outdoors. The design we submitted to the US Department of Energy, in order to be selected for the competition, reflected that lifestyle philosophy and was inspired by the classic Kiwi bach. Our house was a passive house, which means it was designed to maximise the use of natural sources of energy—such as the sun and the wind—to provide heating, cooling, ventilation and lighting. The aim of a passive house is to improve the comfort for people living in the home while minimising its energy use.
After selection we began testing our proposed design using computer simulations and, in the process, realised we needed to rethink our passive strategy for the house if we wanted to compete. The challenge has become to design a house which uses passive solar principals found here in New Zealand while also meeting the strict competition requirements. There are 10 competitions within the Solar Decathlon and one of these is the Comfort Zone competition that requires the temperature inside the house to stay between 21.7oC and 24.4oC, and below 60 percent relative humidity. This is much warmer than an average Kiwi home and the competition requires us to use air conditioning and heating systems to maintain this ideal temperature.
One of the most important areas of our bach design is the central skylight that creates an internal deck area, bringing the feeling of the outdoors year-round. The skylight is an architectural feature of the home and essential to the initial design concept, however it makes it difficult to maintain the temperature we need inside the house under the competition rules. After much discussion and testing, it was decided that we could not give up on what made our design unique, we would have to find a way to achieve the thermal performance whilst keeping the skylight.
We have used thermal simulation to test and compare a wide range of different glazings, shading and insulating blinds to improve the bach’s performance. While New Zealand standards are now recognising the benefits of double glazing, we are looking into triple and quadruple glazing to get the insulation levels we need. It’s a balancing act and to take the Kiwi lifestyle to the world we’llneed to employ techniques from around the world.
Follow the team’s journey so far: