increased biodiversity.
Super Efficient Windows
High Performance windows today feature soft-coat low-E coatings, inert gas in a vacuum sealed air gap, warm edge spacers and more efficient frame technology. The results are windows that block over 70 percent of the solar heat gain and provide overall R-3 thermal resistance. The most efficient windows today enhance performance further with one or two additional low-E glazing layers, gas filled insulating gaps and more efficient framing.
Clerestory windows (pronounced ‘clear story’) are a very versatile way of using daylighting. Historically, clerestories were bands of narrow windows that stretched across the tops of buildings, particularly Gothic churches. Nowadays though, people tend to call any window located higher than average a 'clerestory' window. In either case, the purpose is to incorporate more windows to bring in outside light, fresh air, or both.
Clerestory options
Clerestories are arranged in rows to create a solid band of light in a room. They are typically fixed, but can sometimes be opened to create a method of cross-ventilation. The may either be opened manually, or integrated into an automated lighting control system. Because clerestory windows are normally quite high up, privacy isn’t compromised in the same way as it might be with windows, although curtains or blinds can be fitted to control heat and light levels.
Positioning of clerestory windows
In Australia (and other places in the southern hemisphere), clerestory windows will ideally be located on the north side of your house to avoid direct sunlight penetration. Also, make sure you use double-glazed windows to avoid heat gain in the summer months and heat loss during winter.
Finally, the use of light-coloured baffles helps to distribute the light evenly and even further into your home to give warmth to rooms that otherwise wouldn’t have access to a lot of natural light.
Temperatures average (Cobran, 2009) (Sharp, 2011) (Mcleish, 2006) in winter 17C and summer 26
Deciduous
Plant trees on north side in northern suburns as deciduous and make house warmer in summer and cooler in winter
Issue 1: Rising Temperatures (3oC plus)
- Temperature changes within urban environments are usually more extreme and experience the Heat Island Effect or urban radiation balance, creating microclimates. Here solar radiation on urban surfaces (such as walls, roofs and paved surfaces) is absorbed and transformed into heat, taking much longer to cool off and resulting in higher temperatures in urban areas, resulting in more use of cooling/heating.
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Energy consumed in urban areas by cooling appliances such as air conditioners increase the peak energy load by 3-5% for every increase in 1oC. As difference can be up to 120C between urban developments and rural/vegetation areas (which are permeable and moist), average load increase can reach 30%.
- Perth’s energy prices in households rose by over 14% between June 2012 and June 2014.
- Of this, heating and cooling requirements account for 40% of the average energy usage in Perth households- this figure will only increase if more sustainable alternatives are not sought out.
Solution 1: House orientation and Layout
- Orientation is the positioning of a building in relation to seasonal variations, location in the sun’s path as well as prevailing wind patterns.
- Good orientation can increase the energy efficiency of house, making it more comfortable to live in and cheaper to run.
- The block is an east-west orientated block and is perfect for sun positioning during winter and summer.
- Sun rises in east and sets in west in both summer and winter. However, unlike in summer when sun passes directly over, winter sun passes at angle due to location in southern hemisphere.
- Hence, exposure during summer will be minimal- light directly only striking shorter sides and at other times during day, will pass directly over house.
- Living room to be located in the northern half of house, as this is good for winter sunlight to warm room and bring natural sunlight. In summer, this area is not directly exposed.
- Good orientation can help reduce or even eliminate the need for auxiliary heating and cooling, resulting in lower energy bills, reduced greenhouse gas emissions and improved comfort. It takes account of summer and winter variations in the sun’s path as well as the direction and type of winds, such as cooling breezes.
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The solar passive design of the home is enhanced through the effects of solar pergolas/porches.
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The houses’ roof will be placed on a 35 degree and of incidence with the horizontal, false ceiling axis (as shown in diagrams). This design not only blocks direct sunlight in summer and allows for maximum penetration in winter, but also allows for more effective growth of green roofs.
- Summer sun does not directly strike green roof (located on northern roof so winter sun does) but allows for flow off of rainwater into gutters and pipes.
- Small vents on the southern side of the house ideal for the cool breezes to filter through house and large clerestory windows situated on the northern side to allow hot air to rise and flow out of house.
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Clerestory windows span around in row near ceilings to provide method of cross ventilation and allow rising hot air to flow out. Also provide natural light in summers without requirement of large windows that bring heat in.
- All windows to be of super efficient make that feature soft-coat low-E double- glazed coatings, inert gas in a vacuum-sealed air gap, warm edge spacers and more efficient frame technology. Block over 70% of solar heat gain and provide R-3 thermal resistance- minimizing penetration of heat in summer but maximizing heat absorption in winter.
Solution 2: Thermal Mass Insulation (Not to be used in essay)
- Thermal mass is the ability of a material to absorb and store heat energy.
- Materials such as concrete, bricks and tiles have a high density.
- Using materials that have lightweight such as timber have a low thermal mass. This means that through the hot days throughout the year, they absorb the heat and then at nighttime when it gets colder the heat is released.
- This makes a major difference to the temperature of your house and your electricity bills because you won’t need to use the air-con/ heater as much now.
- So for as many parts of your house as you can try to use concrete, this could easily be used for the floor and walls. Then this house will have a lower temperature on average.
Solution 3: Green/Zincalume roof with Deciduous Trees and Grape Wines
- Deciduous trees (meaning trees that drop all leaves in autumn) and grape vines provide added cooling through the leaf transpiration process. Block up to 90% of direct sunlight if located in correct location.
- When leaf moisture is converted to vapor, there is an evaporative cooling effect as heat is absorbed from the air to convert the moisture into vapor.
- Cooling by evaporation increases as the humidity/moisture in the air decreases.
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It reduces heating and cooling requirements significantly as sunlight is not directly striking rooftop and storm/rainwater runoff is slowed, allowing higher percentage of water to seep into gutters and be reused.
- Sunlight in peak summer strikes trees, or Zincalume roof. Zincalume roof reflects sunlight away, whilst deciduous trees absorb heat. This reduces heat on house and urban developments and hence, reducing heat-island effect (micro-climates).
- Zincalume steel is recyclable reducing the negative environment impact that other roofing materials have.
- A green roof is planted partially or completely with vegetation and a growing medium approximately 200mm deep) over a waterproof membrane.
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Green roofs are an accepted part of modern building in Europe where some city and national governments have mandated their use. In Austria any new rooftop larger than 100m2 requires a green roof.
- The insulating and low thermal absorption properties of green roofs reduce the urban heat island effect. As green roofs have a low thermal mass, heat is not absorbed (only that required for vegetation) and rest is used for evaporation.
- Deciduous trees reduce cooling demands by limiting solar gain in the summer while allowing daylight in during winter when leaves are no longer on tree.
- Green roofs cool the local climate around a building in a city by 3.6–11.3°C and the hotter the climate, the greater the cooling effect- this is a significant amount as Perth’s temperature increase is predicted to be around 3% in the next 50 years- this will be somewhat nullified due to the implementation of a green roof.
- Propose to have Zincalume roof on south, west and east slanting roofs whilst a green roof on northern roof and grape vines down northern side wall with deciduous trees located in north east roughly 15-25 metres from wall- most effective plan.
Issue 2: Declining Rainfall and Water Supplies
- Freshwater is essential to human existence, and to the functioning of the ecosystems that support us.
- Australia is the driest populated continent on earth and can yield limited amount of freshwater. Average annual rainfall in Australia is 469mm a year- well below the global average. Perth’s mean average rainfall is 739.2mm.
- Australians are greatest per capita consumers of water, averaging100, 000L of freshwater per person each year.
- Available freshwater resources are expected to decline with changes to rainfall patterns accompanying global climate change, whilst demand due to rise in population is expected to rise.
- Houses and gardens consume 12% of Australia’s water use.
- In houses, shower is the main water user (34% of indoor water use in average Australian home), followed by the toilet (26%) and laundry (23%).
Solution 1: Rainwater Harvesting
- Rainwater harvesting (also called roof water harvesting) involves the collection, storage and distribution of rainwater from the roof, for use inside and outside the home or business.
- Australia is the driest inhabited continent on earth and in most rural communities rainwater is the only supply of water for human consumption.
- Australians have used rainwater for many years as their source of water for all requirements – drinking, cooking, bathing, laundry and toilet flushing through to watering the garden. This is also true for many other communities around the world.
- Current main water is typically stored in dams, treated with chemicals such as chlorine to kill of bacteria and make it safe, and then pumped through a network of pipes throughout the community.
- Rainwater harvesting will not be required to be treated with chemicals and chlorine-significant health benefit.
- Rainwater Harvesting reduces the significant damage to our creeks, water habitats and organisms caused by storm water runoff.
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For effective collect of rainwater, collection area should be at least 200m2 in area and 2-3 water tanks with a capacity of 12000-20000L each. These tanks can be above ground or in soak wells below the driveway.
- Based on Perth’s current rainfall, this meets internal use of water for roughly eight months of the year (based on the average WA household water usage).
- During summer, water supply can be changed to mains or can implement another sustainable solution such as a grey water extraction system.
- Water prices are expected to increase due to increase in demand and less supply from dams, rainwater harvesting will regulate and reduce water bills- similar to how solar power does to electricity bills.
- The rainfall on each surface is collected in gutters that fall into downpipes fitted with insect and leaf excluding rain heads.
- A ‘wet field’ or ‘charged’ rainwater collection system allows for pipes between gutters and tank inlet to be permanently full of water and hence, keeping system moving efficiently and a domestic pressure pump pushes water along pipes and into house.
Solution 2: Groundwater and Grey Water Extraction and Use
- Groundwater makes up approximately 17% of Australia’s current accessible water resources.
- Groundwater is water located in the saturated zone below the earth’s surface.
- Groundwater comes from two primary sources- rainwater that infiltrates soil until it reaches a water table in an aquifer and from rivers/streams draining into the ground.
- Makes up about 98% of earth’s available freshwater and is particularly found in Australia along coastal plain and large basins in east.
- Use groundwater to replenish grey water supplies, as grey water reuse is more effective.
- Cost around $1200 per house with the grey water system itself including pumps, filters and irrigation costing around $2500 for supply and installation.
- Grey water is household water that hasn’t come into contact with toilet wastewater and water from kitchen due to containing toxic chemicals, fats and detergents, which cause problems with system maintenance and soil health.
- Provides regular supply for irrigation water and is not limited by water restrictions.
- Pumped system that incorporates an automatic filter back flush device- a self-cleaning mechanism that reduces maintenance.
- Water flows from pipework leading from drains and is pumped up through building to irrigation facilities and/or to be used as toilet water.
- This technique means that when there is no grey water to be pumped into irrigation, bore water from storages are discharged when irrigation controller indicates valve-blocking water to open and allow bore water to go through pipes. This ensures no cross contamination occurs between to sources of water.
- On average, 100L of grey water is generated per person per day in the bathroom and laundry.
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Each day, only 10mm of irrigation water is required for an area of 40m2 in soil from the Swan coastal plain. Hence, ground water reserves only required occasionally when house empty.
Step 5: Essay Plan
Introduction/Question 1 response:
• Define the term sustainability in terms of housing.
• Outline makes a good sustainable house in terms of its location.
• Introduce decision to choose plot in Joondalup- Why.
Body Paragraph 1: Introduce the challenge of rising temperatures in Perth
• Predictions for temperatures in Perth in the future- more extreme temperatures expected due to climate change.
• The growth of the heat island effect in Perth due to its continued increase in urban development.
• Suggest some of the challenges rising temperatures pose to Perth households.
Body Paragraph 2: House layout and orientation
• Detail need for good orientation and layout- topic sentence.
• Houses location on east west axis-detail why (sun orientation in winter and summer).
• Talk about inside layout with living room in north for expose to winter sunlight and heat.
• Detail window structures with clerestory windows to increase air flow and allow rising hot air to flow out.
• Explain how modern, super efficient clerestory windows work.
• Introduce roof layout with porches in east and west sides to block direct summer sun.
Body Paragraph 3: Green/Zincalume roof with deciduous trees and grape vines
• Introduce benefits of green and Zincalume roofs. What they are and how they work to absorb/reflect sunlight.
• Implementation of two roofs in house- where/layout and why.
• Benefit of deciduous trees and grape wines- regulation of the heat island effect due to vegetation.
Body Paragraph 4: Introduce the challenge of declining rainfall and water supplies
• Outline why rainfall is important for water supplies and the increase in demand in Perth for water.
• Facts/statistics on current rainfall and future predictions.
• Discuss issues created by declining supplies and two possible issues.
Body Paragraph 5: Rainwater Harvesting
• Introduce rainwater harvesting and what it is- how is it implemented?
• Detail implementation including facts statistics.
• Benefits to be gained from rainwater harvesting.
Body Paragraph 6: Groundwater and grey water extraction and use
• What is ground/grey water and how is it extracted/reused? - Include amount of reserves in Perth.
• Process of groundwater/grey water extraction and system- how to extract and implement.
• Detail how it can solve problem- facts/stats.
• Explain how it can work alongside rainwater harvesting to further reduce water from mains.
Bibliography
Cobran, T. (2009). Eco House Book. London: Conran Octopus.
Living, M. E. (2014, May 12). Mother Earth living. Retrieved February 16, 2015, from How to Keep Your House Cool Without Air Conditioning: http://www.motherearthliving.com/energy-efficiency/how-to-keep-your-house-cool-zmfz12jazmel.aspx
McGee, C. (2012). Orientation. Retrieved Febuary 20, 2015, from Passive Design - Austrlian Governement: http://www.yourhome.gov.au/passive-design/orientation
Mcleish, E. (2006). Sustianable Homes. London: Evan Brothers.
Oz Breed. (2011). Green Roof Trials. Retrieved Febuary 19, 2015, from Greenlife Ozbreed: http://www.ozbreed.com.au/research-papers/greenroof_trials.html
Reardon, C. (2013, april 28). Your Home. Retrieved February 17, 2015, from Thermal Mass: http://www.yourhome.gov.au/passive-design/thermal-mass
Rogers, K. (2014, november 1). Fox Business. Retrieved february 16, 2015, from How to Keep Your Electricity Bills Cool this Summer: http://www.foxbusiness.com/personal-finance/2014/05/27/how-to-keep-your-electricity-bills-cool-this-summer/
Sharp, D. (2011). 21st Century Sustainable Homes. Victoria: The Images Publishing Group.
water, S. (2013, march 2). SaveWater! Retrieved february 16, 2015, from Save Water: http://www.savewater.com.au/how-to-save-water/in-the-home/bathroom