Energy/
22nd Apr 2014/
Rob Lord
Solar Power – Generation and Storage
In order for us to achieve our dream of being carbon neutral in operation it is critical that we address our power needs and consumption. Most people know that there is great potential to create energy from the sun via solar panels (photo-voltaic cells) however it seems that many people are still hesitant to install them due to the cost. Considering that we live in the ‘sunshine state’ it would be crazy to look past utilising this endless source of electricity as we are confident the system will pay itself off relatively quickly. Image 1 shows how the sun is used to power a home.
Having researched the topic further we began to find flaws (unknown to many) in how common solar systems work, including:
1. The majority of the power generated by the solar panels is created during the middle of the day, when the sun is the highest in the sky, whilst the majority of the power used by the consumer is during the night when people are at home (refer Image 2)
2. All excess power generated (that which is not used immediately by appliances in the home) from the solar panels is returned to the mains grid for others to use (refer Image 3)
3. Home owners will no longer receive credits for returning power to the mains grid as of July 2014. Previously there were some financial incentives (rebates) for contributing power to the mains grid but unfortunately this scheme will cease shortly.
After considering the above it became clear that installing a ‘generic’ solar panel system would not allow us to achieve our dream of being carbon neutral. The solution to this, as we later discovered, was to install a battery (refer Image 4) to store all the solar energy we create rather than returning it to the grid. In doing so we could then become truly self-sufficient.
The only other issues to resolve were calculating how many solar panels we required and determining where were they to be placed. Analysis of both the appliances to be installed and lifestyle desired in the new home were key to ascertaining the number of panels necessary. In the end it was calculated that approximately 20 panels would be required to support our needs.
In determining where they were to be placed the following were important to consider:
1. The optimal angle (tilt) and aspect of each panel
2. Shading from nearby structures and how this would impact on each panel
Research showed that an angle of about 27 degrees facing true north was ideal for Brisbane. In terms of shading we undertook 3D modelling as can be seen in Image 5. Note how during the middle of the day there is no shade on the panels, thereby ensuring maximum operating efficiency.
This task certainly opened our eyes to the critical decisions when installing a solar system for your home, especially if you want to get the most benefit from it. We are confident that the system chosen will allow us to live our desired lifestyle without drawing on unsustainable energy resources.
Look out for our next blog in the coming week!
Liveability/
16th Apr 2014/
Rob Lord
The Importance of Radiant Heat Regulation
The effects of radiant heat are an important consideration when designing a truly liveable home. Radiant heat, as the name suggests, radiates from an element and directly warms an object rather than warming the air. A good example of this is a fireplace, or on a larger scale, the Sun. Within the home, radiant heat transfer comes from two sources – the direct radiation from the sun and the radiation of heat to the “night sky” (to outer space). Image 1 explains how radiant heat impacts us.
The sun’s radiation is very powerful – typically 1KW per m2; whilst night sky cooling is weak – a clear winter sky can cool at 170 W/m2. The sun’s radiation is also predominately “short-wave” meaning it can pass through glass easily but once it hits a surface, it becomes infra-red radiation and “long wave”. Infrared radiation does not pass through glass easily. Hence glass helps to trap heat, which is why a greenhouse is primarily made of glass. It traps winter heat to keep the plants warm during winter. See Image 2. With this in mind, it is critical to assess how the sun’s radiant heat will affect a home, and also, when we do and don’t want to trap heat internally.
By looking at a sun path diagram, (refer Image 3), we are able to see the sun’s movement represented by 3 lines – a summer peak (represented as a red line in December 21), a mid season (represented as a green line in March & September 21) and winter minimum (represented as a pink line June 21). Using these lines we can quickly ascertain the periods we don’t want heat and also the period when we do want heat. Further, we can then determine the best way to control the heat gain and loss, which is normally through shading of the building. As most people know, it is the Earth’s tilt that attributes to seasonal variations with the Northern and Southern Hemispheres varying in proximity to the sun throughout the year (refer images 4 + 5).
In Brisbane we aim to restrict the suns radiant heat through the summer months. Specifically, an angle of 630 generally achieves a balance between keeping unwanted heat out in summer months and allowing winter sun in. As mentioned earlier the most effective way to do this is through shading. Image 6 shows how appropriate shading can control the amount of radiant heat that enters a building. Note that it is actually possible to “over-shade” a building. In doing so a building could become uncomfortably cold in winter months.
The extent of heat and the usefulness of heat for comfort’s sake is guided by glazing type & extent and also thermal mass. We will tackle these subjects in upcoming blogs
Design/
04th Apr 2014/
Project Zero
An Introduction to Project Zero
In essence, Project Zero is an environmentally sustainable development that aims to be carbon-neutral in operation. By encompassing advanced architectural design principles, innovative technologies and unique building products we will ensure that Project Zero it is at the forefront of the ‘green-building’ movement. Undoubtedly though, with this ambition comes challenges and tough decisions. This is our story…
Many people have asked us why we are building a sustainable house. It has been an interesting process and the final plans of our home are quite different from our initial concept. Ultimately, our key motivation for building this house is to lessen our impact on the environment, to try to be as self-sufficient as possible and to teach our boys the importance of looking after the planet on which we live. We believe small changes can make all the difference to our planet. There is a definite green movement underway and people have woken up to the damaging affect our lifestyles are having on the environment. It is only when many people start to make small changes in their lives that we will see a big impact on the environment. With the world’s population growing at an alarming rate, we all need to do what we can to preserve nature and lessen our impact on the environment.
Initially, Leon put forward the idea of building a sustainable house using recycled materials from jobs that Apollo Property removed. He wanted to try to reuse doors, plasterboard, glass, and carpet (for insulation). One of the reasons we chose our postwar house in Alderley was because of the relaxed zoning laws which would allow us to basically build anything we wanted. However, as we progressed through the planning stages it quickly became apparent that the logistics and cost involved in removing, storing and then reusing all of these materials made this model too prohibitive. So we began talks with BVN Donovan Hill about a different type of house. We envisioned a house with green roofs and lots of vertical green walls, solar panels, rainwater tanks, grey water tanks, a veggie garden, chickens, a worm farm, bees, a fresh water swimming pool and cabinetry made from ply. A lot of these key elements have flowed through into our current model, however some of them sadly had to go.
One of the first elements to be scraped was the green roof. We were adamant that we wanted one for our house. We had numerous meetings with a specialist in this area and originally had a green roof on the office and on the covered walkway running along the side of the house. The impact from the street would have been sensational, the minute you pulled up out the front of the house you would have seen the greenery rather than a typical roof. However, even when you are the owner/builder the construction costs start to build up. Unfortunately the green roofs just didn’t fit within our budget. We are hopeful that we can still incorporate a vertical garden within the house or perhaps near the pool. Landscaping will be a huge feature and we are still working on the hardscape and softscape areas with Steven Clegg (Steven Clegg Design).
Another key feature that we had to delete was the grey water tank. We loved the thought of using grey water to flush toilets and water the garden. What a great way to conserve water! We understood that you had to be very careful about what soaps and chemicals you put down the drain when using grey water, but didn’t see that as an issue. One thing we weren’t expecting were the restrictions that Brisbane City Council had on grey water use. They only allow grey water to be used for flushing toilets. No grey water is allowed on gardens in Brisbane. Can you believe that? Sydney, Gold Coast and Moreton Bay regional councils all allow grey water recycling. Why not Brisbane? It seems unbelievable?!? After all those years of drought, you would have thought the council would embrace people wanting to conserve water. We couldn’t justify the $10,000 install cost and the $1,000 annual servicing of the grey water tank. So sadly, it had to go too. We are hoping that BCC change their rules, so other people trying to build a sustainable house can conserve their water in such a simple way. To compensate we increased the volume of our water tank. 55,000L is a huge water tank. Most residential houses use anywhere from 3,500 to 5,000L per week, so we are confident that our tank will help us limit the use of town water.
Despite these couple of setbacks, our dream of building a sustainable, carbon-neutral house is coming to fruition. We will have large solar panels on our roof, a fresh water pool, a veggie garden large enough to supply us with our basic veggies and herbs, a chicken pen to supply us with eggs, a worm farm and bees. Actually, I could write a whole blog post about the plight of bees!
By incorporating all of these elements into our home we believe we are well on our way to living off the grid.
