Sustainable construction Flashcards
what are the 8 climate zones in Aus’t
High humid summer, warm winter 2 Warm humid summer, mild winter 3 Hot dry summer, warm winter 4 Hot dry summer, cool winter 5 Warm temperate 6 Mild temperate 7 Cool temperate 8 Alpine
What is sustainable development
meeting the needs of the present without jepodizing the needs and want of future generations
It has been estimated that buildings contribute 40-50% of greenhouse gas emissions globally.
what is energy efficiency
the goal to reduce the amount of energy required to provide products and services
what is thermal comfort
That condition of mind which expresses satisfaction with the thermal environment
The body is in a state of thermal equilibrium with its environment when it loses heat at exactly the same rate as it gains heat. Heat production = heat loss
Comfort = happy = productive = $
Building design needs to be able to do this with as minimal reliance on external energy sources as possible.
what is thermal stress
stress in a body or structure due to inequalities of temperature (opposite of thermal comfort)
airflow (wind),
air temperature,
air humidity, and
radiation from the sun and nearby hot
The personal factors are:
the clothing being worn and
the person’s level of physical activity.
what is a passive design
a rigorous, voluntary standard for energy efficiency in a building, reducing its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling
Passive designed buildings are buildings designed to reduce their ecological footprint.
Explain ‘zero energy buildings’
The overall concept of a Net ZEB is an energy efficient, grid connected building capable of generating energy from renewable sources to compensate its own energy demand.
The word “Net” emphasizes the energy exchange between building and external energy supply (eg. the power grid).
These buildings are typically very energy efficient by design
meaning the total amount of energy used by the building on an annual basis is roughly equal to the amount ofrenewable energycreated on the site.
what is passive solar
building design,
including windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer.
Explain a housing style
Mid-victorian 1860-1875
While retaining a similar form to its Early Victorian precursors, this era of house design is distinguished by a greater level of ornamentation. There is an increased use of stucco on exterior surfaces, while decorative brickwork is prevalent in fashionable houses of the period. Verandahs are common, usually of timber construction and often incorporate cast iron lacework and patterned tile oops.
modern 1945-1970
haracterised by open planning and simplicity with bold geometric shapes and little or no ornamentation. Walls are opened to the light with large oor-to-ceiling windows. The design of the buildings often expresses innovative use of materials and structure
Write a list of 4 environmental &/or external influences that the group believe were important and how they affected housing design
Wealth (size, complexity of design, materials)
The environment (materials, shade, sun, hot, cold)
Functionality (indoor services, layout, garaging)
Technologies (Building Management Systems (BMS), materials eg. Glass)
Demographics (singles, one parent/two parent households.)
Economic cycles (boom times usually create more opulent dwellings… status?)
economy
fashion
environment
5 essential elements of energy efficiency
Materials (conductivity + resistance to heat flow) Orientation Thermal mass Internal planning + room placement Ventilation/leakage/insulation
3 pillars of sustaniability
COST (economic development)
PEOPLE (social development)
EARTH (environmental protection)
sustainable design should consider
Sustainable materials renewable energy health and wellness transportation whole life costs (lifecycle costs) passive strategies
explain main ideas of internal room placement
Avoid conditioning large areas when only smaller areas may be in use
Create zones of synergy Close off unheated rooms
Locate garages and carports on the east, west or south- Protects from summer sun and winter winds.
Create air locks at external doors to prevent escape of conditioned air.
Don’t condition air locks
Keep ceilings low to reduce air
volume.
Place doors at base of stairwells
to prevent heat escape
Avoid westerly aspects for bedrooms
Group wet areas together
Use utility areas such as laundry, toilets, bathrooms as a “buffer” on the west and south sides.
Use doors to close off other areas (and close them!)
Can retain “open feel” with bi-fold glass doors
Place “openable” windows and external doors on different sides to achieve cross ventilation.
Keep paths under 8m where possible-flow intensity can be significantly reduced
wide verandas, can cause poor
thermal performance by shading windows
explain materials resistance to heat
Any given material has a conductive value (k-value). This value (k) is known as a constant as it is the always same for that particular material.
The k-value describes the heat transfer (Watts) through the material. That is the ability of the material to transfer heat energy (or simply just “heat” as most people think of it)
Windows are constructed of glass AND frame they can be
made of various materials and methods.
U-values can be determined for the glass
U-values can be determined for the frame
Why windows can be a problem
(Traditional) windows have virtually no resistance to heat transfer. Internal hot air rises, makes contact with the glass, heat flows from hotter mass to cooler mass and is lost through the glass material.
The Glass house effect: Shortwave radiation passes through glass virtually unimpeded. This radiant heat is absorbed by furniture and building elements which in turn heat up and re-radiate heat into the room
External shading can block up to 80% of summer heat gain
Internal window coverings + double glazing can reduce winter heat loss by apx 40%
Define thermal mass
Thermal mass is the ability of the material within the building to provide “inertia” against temperature fluctuations. It the materials ability to absorb heat, store it and at a later time release it.
Summer Absorbs heat entering the building Acts as a heat sink (lower initial temperature) Heat absorption lowers internal temperature during day
Winter
Thermal mass in floor absorbs radiant heat from sun (orientation?)
Heat slowly released during night
Need for supplementary heating is reduced
For good winter performance, thermalmass be exposed to direct sunlight and best be north facing.
Explain thermal mass relation to location
Maximum effectiveness by;
Insulating external walls
Locating within the insulated walls
(external brick walls of little use as they are external)
Locate throughout the dwelling
Shading windows in summer
Minimising covering with carpets (acts as an insulator)
Balancing north facing window area with amount of thermal mass (more window area-more internal mass)
Explain leakage
External wind movement creates pressure difference between inside and outside
Causes some external air to be forced inside (infiltration)
Causes some internal air onthe leeward side to be sucked out (exfiltration)
explain ventilation
Controlled air movement
Good ventilation needs to be “designed” into the home.
Can be via use of natural air flow or mechanical (fans).
Air speeds greater than natural air leakage has a cooling effect on the human body.
At air speeds between 0.5 to 1.0m per second, the body will feel 2-3.C cooler in 25C air
Continued development of mechanical heat recovery technology will assist in the future.
plan inferior to:
Avoid air pockets (stale air.)
Allow even-flowing air.
Extract odors/steam mechanically (ie: control it.)
Try to achieve minimum 0.5 air exchanges per hour.
Measures to reduce unwanted air flow are relatively cheap:
sealant
door seals
The “tighter” the leakage the more important controlled ventilation becomes
To obtain maximum benefit of ventilation must open both sides of house. Opening inlet only will mean internal air speed is around 4% of the external air speed. If both opened then internal air increases to approximately 35% of external air speed.
Can utilise the “stack” effect - cool air absorbs heat as it passes and rises
What is thermal coupling or bridging
Thermal bridges are points in the building envelope that allow heat conduction to occur. Heat will flow from the hotter area to the cooler area.
e.g.
Window frames (Eg: Aluminium)
Studs between insulation panels
Concrete floor (slab on ground)
What do you think governments can do to aid public acceptance of sustainable housing
the need for economically achievable housing for all socio-economic sectors and the provision of community based lifestyle.
Satisfaction with our immediate environment is essential to long term stability and harmonious living. Government needs to adopt a medium and long vision towards sustainable housing that sometimes is not popular. Policy development must address both individual housing and urban planning with the view towards gaining acceptance and co-operation
Consider some basic features you would include/exclude if you were designing a house in Northern Australia (Darwin) and Tasmania (Hobart.)
Ans: eg: Northern climates require air movement; such as homes with windows that capture sea breezes or have elevated floors to allow air-flow under the house.
The 3 basic forms of energy consumption in housing are embodied, in-use & locational. What do these mean in terms of sustainability?
Embodied energy is energy consumed in the construction of the dwelling. It includes transportation of materials to the site, energy used in the production of the materials and other associated energy such as fuel used for trades to access the site.
In-use is the energy consumed in providing a safe and comfortable environment for occupants. It includes the operation of appliances, heating/cooling, lighting etc.
Locational is about travel requirements that are necessary for work or other activities.
