Redução do Impacto do Ciclo de Vida do Edifício – LEED (Portuguese)

Análise de Ciclo de Vida (ACV) é uma metodologia usada para avaliar os impactos ambientais associados a todas as etapas da vida de um produto ou serviço. É uma abordagem holística que engloba a extração dos materiais, processamento, fabricação, distribuição, uso, reparo, manutenção, descarte e reciclagem ao fim da vida útil. A ACV quantifica os impactos ambientais e compara a performance por meio da funcionalidade do produto ou serviço. A performance de um prédio comercial, por exemplo, pode ser avaliada por meio do impacto ambiental por m2 de área locável por ano (kgCO2/m2/ano). O estudo de ACV permite identificar as potenciais áreas para aumento de performance e redução de impacto ambiental, podendo também incluir recomendações de melhoria para a equipe de projeto. A ACV é regulada pelo padrão internacional ISO 14044 (e EN15978 especificamente para edificações) e a aplicação na área de construção civil é utilizada mundialmente para promover desenvolvimento sustentável.

Na certificação LEED, o objetivo do crédito Redução do Impacto do Ciclo de Vida do Edifício é otimizar o desempenho ambiental de produtos e materiais e permite obtenção de até três pontos. Apesar da metodologia permitir avaliar impactos relacionados a todo o ciclo de vida do projeto, este crédito LEED (opção 4) tem o foco apenas na estrutura e recinto do edifício, durante período de 60 anos. Ao comparar a performance do projeto proposto com o modelo de referência (Baseline), a equipe de projeto deve demonstrar redução de impacto de no mínimo 10% em pelo menos três categorias de impacto (por exemplo: aquecimento global, depleção da camada de ozônio e eutrofização).

A eTool, empresa Australiana especializada em avaliação do ciclo de vida de todo o edifício, desenvolveu o software eToolLCD que atende aos requisitos técnicos da norma ISO 14044 e pode ser utilizado na certificação LEED. A eTool iniciou operações em 2012, já completou mais de 300 análises internacionalmente e é pioneira no uso de ACV para certificação na Austrália (Green Star). Atualmente, está expandindo os serviços na Europa (BREEAM) e nas Américas. Os projetos LEED que utilizaram o software eToolLCD incluem: King Square 2 – Cundall (Austrália), Wildcat Building – Arup (Dinamarca) e ENOC Tower – AESG (Dubai).

“A única forma de garantir redução de impacto ambiental é quantificar a performance ao longo da vida útil do projeto e a metodologia de ACV foi desenvolvida para auxiliar na tomada de decisões. Este crédito LEED será muito importante para as equipes de projeto trabalharem de forma ainda mais integrada e o software eToolLCD facilita muito esta análise”, afirma Henrique Mendonça, engenheiro da eTool que está de volta ao Brasil depois de passar cinco anos na Austrália e se especializar na prática de ACV de toda a edificação.

Saiba mais sobre nossos projetos recentes aqui.

 

 

LCA – More than just easy credits

Since being awarded IMPACT compliance in Christmas 2015 eTool now have many clients successfully using eTool on either a consulting basis or as LCA software providers.  With an IMPACT compliant LCA they can guarantee the two bonus LCA Materials credits in Breeam New Construction 2011/2014. These credits are awarded as a bonus to the Green Guide materials credits and awarded for completing an LCA and reporting on the results. 6+1 credits can also be achieved under Breeam Fit-out/Refurbishment/International, up to 23 credits in HQM and 3 under LEED.  The tool can also be used to assist in life cycle costing Man 2 credits, and Mat 06 Resource Efficiency.  The Bre are trying to encourage uptake in LCA and for the time being the credits can be applied at any stage of the design – effectively points for trying.

Below are just some of the clients who we have been working on LCAs with to date.  Although the primary motivation is often Breeam related, LCA is also providing some fantastic learning outcomes for design teams.

etoolclients

“We have been using eToolLCD for the last year and have completed 3 certified assessments.  As with any new software there is a learning curve involved but the training and level of support has been excellent and we can now complete an IMPACT assessment on our project in a couple of days (depending on complexity).  This has enabled us to give our clients and design teams valuable information on the environmental impacts of design options as well as giving an additional 2% to the projects BREEAM assessment once the eToolLCD model has been certified.” David Barnes, Volker Fitzpatrick 

Find out more about our recent projects here.

 

 

GBCA Feedback

eTool drives on innovation and forward thinking to bring solutions and help us mitigate environmental impacts. We have been working closely with GBCA since 2013 when LCA was included as an Innovation Challenge. Since completing its first LCA later that year, eTool has become a leader in providing consultancy and software services related to LCA for the Green Building industry.
There are now over 50 projects that used eToolLCD to achieve the Materials Life Cycle Impact credit and technical experience was developed internally at eTool and amongst software users.
The construction industry is moving to LCA for environmental decision making, and recognising that the only way to prevent adverse trade off is to use life cycle assessment within a life cycle design process. Following this global trend, eTool thought it was very important to provide feedback when GBCA opened for public consultation. Here are some of the key points included:
• Consideration of functionality in the principles, and use of LCA as early as possible to inform the design process.
• Normalisation and weighting should be considered to prevent negative trade offs between environmental impacts and guarantee whole of building performance.
• Use of LCA model to calculate GHG, Water and other life cycle impacts because it is very flexible, it delivers good environmental outcomes and it is aligned with global trend, which simplifies the maintenance of GS calculator tools.
We look forward to the advancements of LCA use within the Green Building industry so please stay tuned for more news on this soon.

 

Closed Loop Recycling and EN15978 – how does it work?

I’ve heard its complicated why is that?

We need to reward recycling but also have to be careful not to double count the benefits (at the start and end of life for example).  The approach under EN15978 is as follows:

  • to reward “design for deconstruction” as the key driver that determines the net results over the whole life of a building
  • to allocate economically, so if a product is a waste product at the end of the buildings’ life (there is no market for it, so it costs money to remove it from site rather than having some sort of scrap value) then any benefits associated with recycling that product are picked up by the next person who uses it.  So essentially, recycled timber is all rewarded at the start of the building’s life.  Recycled aluminium is all rewarded at the end (in net terms)

Allocation of reused products from other industries are also done economically, one example of this is recycled fly ash or blast furnace slag in concrete.  Because Blast Furnace has some value, it’s not as attractive environmentally as fly ash

The rules for recycling allocation under the EN15978 methodology were initially somewhat mind-boggling for me.  To understand them you will  likely need to take a number of re-visits and you should try to wipe out any preconceptions you may have on recycling.

So how does it work?.

Lets start with what is included in the scope of En15978 first,

boundary

Note that Module D is actually a form of “System Expansion” and one could argue is outside of the life cycle of the building.

Before we look into recycling allocation further we also need to understand a few definitions.

Recycled content is the proportion of recycled material used to create the product, the global industry average recycled content of aluminium today is approximately 35%. This means that in 100kg of aluminium 35kg comes from old recycled aluminium and 65kg comes from new raw material.

Recycling rate is the proportion of useful material that gets sent back into the economy when the product comes to the end of its life. The global industry average recycling rate of aluminium today is approximately 57%. This means that in 100kg of waste aluminium 57kg will be recycled into new aluminium products and 43kg will be sent to landfill.

Closed loop recycling, whereby a product is recycled into the same product (e.g. steel roof panel recycled into steel reinforcement).  The loop is closed because when the steel product comes to the end of its life it can be recycled into a new steel product (theoretically this can happen continually forever).  Closed loop is more straightforward to calculate as the emissions are directly offset by the new product that would have been required to be made from scratch.

Open loop recycling is when the product is used to create something new (e.g. old plastic bottles recycled into carpet).  The loop is open because the plastic now in the carpet required other material inputs to create the carpet and cannot be recycled further (if a process is developed that can continually recycle the plastic carpet then it becomes closed loop). We use economic allocation to understand the impacts that are being offset.

Now lets focus on a closed loop recycling example of a standalone 1000 kg of ‘General Aluminium’ modeled in eTool.  Under EN15978 scope impacts under module D – Benefits and loads outside the system boundary are quantified.  This includes closed loop recycling which is not directly related to the actual physical boundary or life cycle of the building.

The life cycle stages for the aluminium are shown below

alum recy 1

Kg CO2e by LC stage for 1000kg of general aluminium 

Hang on, the impacts are bigger for the 100% recycled content option???

Well, there is an initial saving in the product stage of 18,280 kg CO2e from using 100% recycled content aluminium versus using a 100% raw material. The no recovery option also gets a small advantage for transport of waste (C2) because landfill sites tend to be closer to a building than recycling sites on average. The no recovery option is also (very slightly) penalised for disposal impacts, if the aluminium is recovered it has 0 disposal impacts because it is sent to the recycling plant and these impacts are counted in the A1-A3 stage of the new aluminium product. The interesting result though is in the closed loop recycling.  We have a credit applied to the aluminium that is recovered and put back in the economy. This is effectively offsetting the assumed extraction requirement for the new aluminium to be used in the (aluminium) economy – for example in the next building.  Likewise aluminium that is not recovered causes a higher net demand for new aluminium.  To determine the ‘credit’ or ‘penalty’ at the end of the building’s life, the net increase in new aluminium required due to the use of the aluminium in the building is calculated.  In the 100% recycled content, 0% recovered the material is penalised by the equivalent mass of new aluminium which will need to be extracted to supply the next building.

Hmmmmmm…

Yes it may seem counter-intuitive but try to think of the world aluminium economy as a single life cycle entity.  If everyone used only 100% recycled aluminium that has 0 end-of-life recycling rate (ie it ends up in landfill) then we would soon run out of recycled aluminium available.  We would have to go back to using raw aluminium (maybe even start digging it back out from landfill!).  By encouraging recovery of the aluminium EN15978 is trying to discourage the overall extraction of the raw material.

O.K. That wasn’t too bad

So far so good but it gets trickier! Lets imagine we have fully recycled content and fully recovered aluminium,

Well you get the best of both worlds – reduced product stage and closed loop credits right?

Wrong!  Here is what happens….

alum recy 2

Kg CO2e by LC stage for 1000kg of general aluminium 

The minus CO2e credit at end of life can not be applied in this instance because you are already using 100% recycled aluminium. There is no material extraction in this case to offset and your end-of-life credit is 0. You don’t get penalised for the added extraction for the future building but you don’t get credit for it because that has already been given in the product stage. Under EN15978 there is actually a very similar amount of carbon associated with a 0% recycled/100% recovered aluminium scenario and a 100% recycled/100% recovered aluminium.

Whoa, that’s deep.

Its a tricky one and there is certainly an argument to say this is not encouraging the right behaviour but the emphasis on end-of-life treatment means that the impacts are accounted for and credit is given without double counting.

So what do we take from all of this?

Recycling content and rate is an important consideration in buildings but it is no silver bullet. Every little helps in sustainability though. Focus on the durability and deconstructability of the product over the recycled content which under EN15978 has a relatively small impact on the environmental performance.

*Note figures show are taken from eToolLCD September 2016

References: Recycling Rates of Metals, T E Graedel, 2011

the-new-perth-stadium-and-sports-precinct-amphitheatre

Perth Stadium – Kicking Goals with LCA

As part of an overall environmental strategy stipulated by the State Government, LCA has been integrated into the design and construction of Perth Stadium.  eTool produced life cycle assessment analysis in three stages forming part of the overall design strategy as outlined below.

 

the-new-perth-stadium-and-sports-precinct-view-from-the-south-east91476cb055b76ffab2a0ff0100ce4282 the-new-perth-stadium-and-sports-precinct-athletics-format

 

Process

Stage 1: An initial “Targeting Study” was completed during bid stages whereby two initial models were developed – an initial LCA model of Perth Stadium and a benchmark LCA model of the already constructed Etihad Stadium (Melbourne) which was considered a typical stadium build.  From the outset, Perth Stadium was indicating an improvement over the benchmark due to the predominantly steel structure which is inherently lower in CO2e emissions compared to concrete structures.  The targeting study also highlighted a number of CO2e hotspots such as food and drinks refrigerators which are typically left on between games.  Controls to switch off non-perishable items between events were an obvious easy win and one which the design team was confident in being able to implement.

Stage 2: As the design progressed, further information became available and the models accuracy was increased and consolidated with bills of quantities.  With steel and concrete contributing the majority of the embodied impacts, it was important that these elements were accurate.  The refrigerant gasses for chillers and food refrigerators was also included which contributed over 2% towards the total CO2e impacts, with the Stadium seating also found to have very high recurring impacts.  Strategies put forward included using a low impact refrigerant such as CO2 and specifying extended warranties for the seating in order to increase the duration of their useful life (hence lowering their impact).

Stage 3:  The model was finalised to include all recommendations uptaken as well as final quantities for materials and energy modelling figures.  The design team were able to implement the following:

Strategies to switch-off non perishable item fridges between events

Blast Furnace Slag replacement in some structural concrete elements

Extended Seat Warranty effectively prolonging the predicted lifespan of the seats

The State LCA requirements were as follows.

– a 7% reduction against the benchmark in product stages (A1-A5)

– a 5% reduction in Maintenance stages (B2-B5)

– a 20% reduction in Operational stages (B6-B7)

Results

The LCA analysis was able to successfully show performance against these impacts and quickly develop effective strategies to meet the targets.  The final design specification shows overall life cycle impacts of 7.68 tCO2e/seat/year; which when split across the planned 37 events per year results in impacts of 0.2 tCO2e/visit.  This exceeds the targets with a

– a 9.1% reduction in product stages (A1-A5)

– a 8.1% reduction in Maintenance stages (B2-B5)

– a 32.2% reduction in Operational stages (B6-B7)

The study also highlights the importance of taking a Life Cycle approach towards targets.  When targets are set for individual elements perverse outcomes can occur.  For example, PV panels are very effective in reducing life cycle emissions in Western Australia, however in this instance they would negatively affect the maintenance target (due to the replacement of the panels).  eTool recommends that a single whole of life approach is taken to ensure absolute environmental benefit is achieved.

David Barr - Gen Y

LCA Reveals Carbon Savings For LandCorp’s Gen Y Winner

The ‘Step House’ by David Barr Architects is the winner of the LandCorp Gen Y competition for unique and sustainable residential dwelling design concepts that encapsulated the Generation Y lifestyle.

The  project is located within LandCorp’s White Gum Valley, an innovative residential development located 3km from the Fremantle city centre. David Barr Architects conducted a full eTool Life Cycle Assessment of the project, which helped to inform additional innovative sustainable design features.

Some of the features include the installation of a 9kw PV system, low embodied energy materials, energy efficiency measures and low water use. The carbon emissions per occupant per year is estimated at 64kg, which is 98% lower than the average equivalent Australian residence.

Read more about the Gen Y project here >>

 

Coles

Coles Becomes First Australian Supermarket to Undertake LCA

Coles has become the first supermarket in Australia to use life cycle assessment and has achieved a 4 Star rating from Green Star.

Leona McLaggan from SD Consultants took the eToolLCD software in-house and used eToolLCD to help achieve the LCA credit in Green Star.

Coles has achieved:

  • 50% more fresh air compared to minimum standards, through high-performance heating, ventilation and air-conditioning systems
  • 15% reduction in greenhouse gas emissions, with highly-efficient chillers and heat reclaimed from refrigeration cases used to supply heating to other parts of the supermarket
  • LED lighting installed throughout, reducing energy consumption and internal heating loads
  • 70% reduction in water consumption, compared with traditional supermarkets, from a range of water-efficiency measures, including water-efficient fixtures and fittings, and 150,000 litre capacity water tanks

Click here for a full article by the Green Building Council of Australia.

LoveLCD_Banner

{#3} Why Love LCD? – It offers an integrated design process.

Our “Love LCD” campaign is now in full swing and we’re excited to release our videos over the coming weeks. We started this campaign because we are passionate about reducing carbon in buildings and to us, life cycle design is the best way to do that. We want to spread our love of LCD and hope others will be inspired to learn more and use Life Cycle Design too!

Why Love LCD?

{Reason #3} LCD Offers an Integrated Design Process.

Watch Alex Bruce (eTool Co-founder and Business Development Director) tell us why he loves Life Cycle Design.

Check out our other ‘Love LCD’ videos:


{#1} Life cycle assessment allows you to identify the sometimes surprising aspects of a design that can be improved.


{#2} LCD takes the guesswork out of sustainability


carpark

Car Park Lighting Sensors

So if you’re designing an apartment building and you’re stuck with an underground car park things can get pretty nasty with energy consumption.  With no natural light and a clear safety requirement to keep the area lit all things point to an energy hungry lighting solution.   Even the most efficient lamps will still burn a lot of power running 24 hours a day, 365 days a year.

The most obvious solution to drop run time is lighting controls.  Specifically motion sensors.  But how should these be set up, and how does the set up (number of lamps per sensor and lamp shutoff delay) actually effect the energy savings the controls will achieve?  The short answer is, make sure they turn off really quickly after the car or person is out of the area.  The long answer is below:

It’s Complex…

The interplay between the car park layout, vehicle traffic, pedestrian traffic, simultaneous use of certain areas of the car park, probability of a specific car bay being accessed, the shut-off delay timing and the distribution of sensors means calculating light run time is very complex.  Pondering the possibilities got the better of me and I ended up running a simulation to determine effect of some key parameters.

A Conceptual Car Park

The conceptual car park looked like the below pick.  Effectively 150 bays with one pedestrian access and a main vehicle exit point at one end.

Car Park Map

I used some basic lighting design to work out how many lights would be needed (single globe T5s) to achieve an adequate light levels (50lx).  The calcs indicated a requirement of about 80 lamps.  I just placed these in the road ways and walk ways in my conceptual design.  These are the numbers with the x in front of them.  In reality they’d be probably be spaced more evenly but this satisfies the requirements of the model which is just to see how many lights would be triggered when each bay was accessed.

Which Car Bay Triggers which Lamp?

That was a manual process of thinking about how a person will walk from the lift to the car, and then how they will drive out (or vice versa).  The below diagram shows that if car bay 125 is accessed the blue line will be traversed by the car driver and passengers, whilst the red line will be travelled by the car.  All the lamps highlighted in red will subsequently need to fire.

Car Park Map - Lights Triggered By Bay 125

Simulation

I got some stats on how many trips and average household does from here and here.  The Sydney data also gave these neat graphs on when the trips occur as well.  This enabled me to put a probability on a given car being accessed at a certain time of the day.  The sensors are obviously going to give the most benefit during lower trip frequency times.  But depending on the set up, you can even get a reduced run time during the peak times in this car park (not every day, but some days there’ll be savings due to the random nature of when people take a car trip).

Screen Shot 2015-05-24 at 2.59.53 pm

After some sense checking I ran the simulation for different combinations of motion sensor parameters.  The focus was on:

  • The delay before the lamp is shut down after the motion sensor is activated (or re-activated)
  • The number of lamps per sensor (if you whole car park is wired to one sensor, you’re not going to get as much benefit)

The below chart shows the results.  It looks pretty clear that the most important attribute is the delay before the lights are shut down again.  Amazingly, with 10 lamps per sensor a 90% run time reduction could be achieved if the lamps only fired for a minute.  10 lamps per sensor is probably as sparsely as you’d want to space the sensors to make sure they fired when there was movement

Simulated Car Park Lighting Energy with Sensors

Pit Falls

The simulation is obviously not a real live thing so I want to note some possible pit falls.

  • I got lazy and didn’t model weekend days separately.  So the actual savings are probably greater than what I’ve reported above.
  • If you car park is full or big rodents that trigger motion sensors 24 hours a day, the savings won’t be achieved.
  • My “Shut off delay time (mins)” is actually the lamp run time from when the motion sensor is first fired during a particular event, not from when it was last fired during that event.  So for you to achieve the 1 minute shut-off delay, you’ll probably want the light to go down 5 or 10 seconds after there was no motion in an area.  Perhaps this would cancel out the additional savings you’d get from lower weekend trips.

Other Car Park Lighting Ideas

Although motion sensors in car parks are an absolute no-brainer, there are also other things that can be done to make car park lighting smarter, a few of which I’ll include below.

Lux sensors may also be utilised with dimmable lamps to ensure light levels over the requirements are not delivered and hence energy savings may be achieved due to lower average lamp power.  The benefit of lux sensors in underground car parks is limited however due to a lack of natural light.

A better coefficient of utilisation can be achieved with light coloured rooms (more reflectance, so better light utilisation from your lamps which means you’ll need less lamps).

The lamp itself should be considered carefully and in conjunction with the lighting controls.  The most efficient globe in the world may be the wrong choice if you need more of them than necessary.  Similarly, if it won’t handle being turned on and off all the time, that’s going to be a problem.

The light housing can also help if it’s got a nice reflective backing to disperse the light where it’s needed (down and sideways) instead of where it’s not (up).

Sustainable Design Principles 101 – Multi-Residential Australia

This post is designed to guide design teams during early design stages prior to any form of drawing mark-up. It describes a pathway of continuous building improvement through easy low hanging fruit strategies to incorporation of renewable technologies and advanced design principles. As sustainability becomes engrained in the construction industry it is important that stakeholders maintain an understanding of what the market expects both presently and going forwards into a low carbon future.

Capture

Achieving Targets – The Basics

Generally a multi-residential apartment building built to BCA standards (electric hot water, 6 star Nathers and standard air conditioner) will have approximately the same impacts as the benchmark average dwelling (4.2 tonnes/person/year). They tend to be smaller (less space to heat and cool), have longer design lives and high occupancy (reducing the impacts on a per person per year basis). The chart below represents the life cycle Impacts of a typical multi-residential apartment building.

Capture 2

Typically there are a number of “low hanging fruit” design improvements that are low cost and low risk to implement. The measures focus on operational energy which generally makes up 70%-80% of the total life cycle impacts. The measures are detailed below for a standard apartment building with a mix of one and 2 bed apartments, please note these are indicative figures and will vary depending on final design, density, services and materials used.

Sustainability Measure

Typical percentage improvement
Gas hot water system 25%-30%
Lighting motion sensors/timers in common areas 6%-8%
Apartment Energy Monitoring 2%-4%
Behavioural Change Programs 2%-4%
Low flow shower heads (5l/minute) 1%-2%
Limit refrigeration space to less than 750mm 0.6%-0.7%
Ventilated refrigeration cabinetry 0.4%-5%
Total approximate 37%-45%

 

With implementation of the above measures the building will achieve approximately a 37% to 45% improvement sitting at a Silver medal rating. To achieve greater improvements renewable technologies are needed.

 

Renewable Technology Typical percentage improvement
Solar Hot Water (1m2 per dwelling) 3%-4%
Solar PV (1kW/ 10m2 per apartment) 5%-7%

 

The majority of medium rise flat roofs can easily accommodate the above with room left over for other elements such as flues and skylights. The low hanging fruit combined with some renewable generation will typically achieve around a 45-55% improvement.

 

 Achieving Targets – Best Practise

For higher ratings to be achieved, there will need to be upwards of 1 kW and per apartment and over 10m2 of roof space available alongside the measures detailed above. This can require careful consideration of roof designs from the outside and in some instances, consideration of options off-site such as community owned solar PV farms may be required.

Renewable Technology Typical percentage improvement
Solar PV (2kW/ 20m2 per apartment) 10%-14%
Solar PV (3kW/ 30m2 per apartment) 15%-20%
Solar PV (4kW/ 40m2 per apartment) 20%-28%

 

Roof Orientation for PV:

Capture3Once a residential building gets above 4 storeys, or a commercial building gets above 3 storeys, it will likely end up in a position where the solar technologies that are required are constrained by the roof space that is available. In this situation the design team should take roof design into consideration from an early stage and optimise it for solar panel installations. The following guidelines should be considered:

  • By installing panels “flat” on a roof, many moor panels can fit because they do not need separating for shading.
  • Shading from surrounding objects and buildings is an important consideration however it is rarely a problem in multi-residential buildings taller than their surroundings. PV can be very worthwhile even if partially shaded and can may still deliver significant carbon savings compared to other measures.
  • For designing roofs in this situation, the following considerations should be made.  Note that the below loss figure for varying orientation and pitch are applicable to Perth (latitude of 32 degrees):
  • The orientation of the roof can significantly aid the amount of PV or Solar Hot Water that can be installed in the diagram above

– North facing panels at 32 degree pitch gives optimum energy gain over the whole year (100%)

– Dropping pitch to 5 degrees only results in a loss of approximately 9% (91% of optimal generation)

  • If panels are to be pitched at lower than 10 degrees, consideration should be given to at least annual cleaning until it is proven that soiling is not effecting generation.
  • If possible, avoid hips in roofs as these significantly reduce the amount of PV that can be installed.  It is far better to pitch the roof in two directions only.  Even pitching north and south in two directions is likely to result in a better overall result than in four directions.  The south facing panels may generate less power per panel than the east or west, but more panels will be able to be installed because hips won’t have to be avoided and this will more than make up for the slight loss of efficiency in south facing panels.
  • Very wide gutters can significantly affect the available roof space for solar collectors.  Consider overhanging the roof structure over a required large gutter.
  • Protruding services that break up the roof space should be designed if possible on the south side of the building.  This reduces the losses due to shade for solar collectors across the whole roof.
  • Roofs with multiple heights are complex due to overshadowing.  If possible avoid this.

For solar hot water systems the same rules apply however slighting more consideration may be required to match demand with pitch, so a higher pitch to meet the higher winter water heating demand.  This is not such an issue with PV as it can be fed into the grid when generation is higher than demand.

 

Advanced Design

Some of the recommendations listed below represent paradigm shifts not only in actual construction but also in the marketing and sales strategies that may be required to ensure a developments viability. There may be times when it makes more sense to invest the money that would go into some of these expensive onsite solutions to other local projects that can deliver more value and higher CO2e savings. Examples of this may include Investments in street light upgrades, existing housing retrofits, solar panels on local schools and buildings, behaviour programs, community farms, bicycle infrastructure etc.

Functionality

The more people a building can house the less impact per person that building will have. Furthermore for every person that is housed in a sustainable building that takes one more person out of the average, unsustainable building – moving society towards a low carbon economy faster.

Typical multi-residential buildings have approximately 50% of the total floor area dedicated to actual living space, the rest tends to get tied up in common areas, car parks, plant rooms etc. By minimising the common areas you reduce impacts on two fronts: living area available for the same volume of materials, and reducing the operational energy required to light and ventilate the common spaces (this can typically take up to 15% of the total CO2e emissions).

 

ratio net dwellable area/gross Floor Area Life Cycle Reduction in Emissions
45%
50% -3.1%
55% -5.6%
60% -7.7%
70% -11.0%
80% -13.5%

 

There are numerous ways that common areas can be reduced:

Capture 8

Space efficiencies can also be gained by increasing the number of stairwells whilst reducing the common walkway areas.

Capture4

Although stairs are likely to be the more expensive option, this could be recouped by adding the spare hallway space into each apartment, in the example above this provides an extra 8.75m2 per apartment.

Typology (Beds and bathrooms)

Environmental impacts can be reduced through increasing the occupancy of the apartments themselves. Whilst 2 bedroom 2 bathroom apartments are fashionable, with good design that (rarely used) spare bathroom could be a third bedroom instead. This provides an increase in the overall sustainable living space of the building without impacting on the floor area being constructed

 Materials

In many ways embodied carbon is equally (and perhaps more) important a consideration than operational energy. eTool LCAs will typically assume current grid intensities throughout the 100+ year predicted design life of a building. This means operational energy makes up around 80% of the total impacts. In reality over the next 100 years the grid will decarbonise and operational energy will contribute much less over time. The embodied carbon in materials on the other hand is locked in from the year the material is manufactured and transported to the site. There are many low impact alternatives to common materials in construction. Timber and CLT can be used in place of concrete and steel. Where concrete is necessary fly-ash or blast furnaces slag blends should be incorporated, these are waste products that can directly replace a proportion of the concrete thereby reducing its impacts.

graph 1

Timber veneers and plywood should be avoided due to the high impact of the glues and resins used in these products. Plasterboard also has very high impacts. Alternatives such as plain hardwood, bamboo or MDF represent significant savings. IF plasterboard is to be used 6mm sheets should be preferred to 12 mm sheets with acoustic requirements met through insulation which is typically low in CO2e emissions.

graph 2

Carpets (especially wool) should be avoided with cork or polished concrete finish preferable. If absolutely necessary carpets should be dark coloured (to avoid replacement through soiling) and plant based materials such as jute and sisal should be specified that have natural/non-synthetic rubber backing.

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Lighting

There tends to be little difference in terms of environmental benefit between CFL lights and L.E.D lighting Increasing natural light levels using solar-tubes, skylights or similar means less use of artificial lighting energy. Specifying lighter matte colours to surfaces such as the balcony, ceiling and walls will bounce light deeper into the dwelling thus increasing natural lighting. Light shelves in windows is another passive way to divert and bounce light deeper into the dwelling. Similar systems using adjustable louvres can also be used. Providing translucent shading material in addition to heavier curtains allow the option of diffused daylight to penetrate whilst maintaining privacy. The top of the windows is where light penetrates deepest into the dwelling, so it is important to ensure that this part of the window is not obstructed by drapery or blinds. Translucent partitions between rooms also allow light to be drawn into deeper rooms. Clerestory windows also provide a method of introducing more natural light into central rooms.  Ideally these should be utilised with higher ceilings and high reflectance surfaces in order to encourage light to penetrate.  In order to prove the value of these initiatives a daylighting simulation should be undertaken to ensure expense is not incurred for no benefit.  This will likely make this recommendation hard to justify economically (there will be many far easier wins elsewhere in the building.

Gas cookers over electric

In regions with fossil fuel dominated electricity grids such as WA, gas represents a large advantage over electricity for providing energy to cook with.  This is due to the heat and electricity losses associated with distributed power.  Burning the fuel (gas) at the source eliminates these losses and is a more efficient way of using the fuel. The majority of gas cookers sold today include safety features that automatically turn off the gas when no flame is present. Rinnai has also developed the ‘inner flame’ technology that produces a flame that is directed inwards which is about 27% more efficient than standard gas stoves. The drawback to moving to gas cooking is that a gas pipeline may need to be installed. If the implementation of this strategy is outside of the project budget the developer may offer the strategy as an upgrade package for purchasers. This eliminates the need for upfront capital while promoting best practices and educating the public.

Or Induction cooktops

An all induction cook-top is an alternative that could deliver carbon savings over a standard electric cook-top.  Induction cook-tops work by transferring electrical energy through induction from a coil directly to the magnetic pan. Only the area in contact with the coil heats up and therefore the cooker can be up to 12% more efficient than a standard electric conduction cooker.  The controls on an induction cooker are also far more precise giving a greater range of cooking techniques.

Car Park Ventilation

By applying a detailed engineering design to the car park ventilation systems, it is expected that the fan run times could be considerably cut down especially when natural ventilation is utilised.  Computational fluid dynamics would be utilised in this technique to determine how to best move air through the car park to maintain acceptable CO2 levels with minimum energy demand.  Gains may also be achieved in reduced ducting.  At least a 20% saving in ventilation may be achieved.

Biodigesters

Biodigesters turn food and or human waste into gas that can be used in cooking. Although not well established in western countries this technology has been used for hundreds of years in China and India. Communal or individual systems exist that may be incorporated into an innovative building design.

 Appliances

The appliances that go into the building can make a significant proportion of the recurring impacts.  Modern appliances tend to have fairly small warranty periods in relation to the lifespan of a building.  TVs in particular can often not last more than 10 years.  Ensuring that appliances are purchased second hand and those that are purchased new have a long warranty and are kept for as long as possible can provide significant carbon savings.  In this recommendation we have assumed each appliances lasts twice as long as the standard warranty. Where appliances are installed they should also be of the higher MEPS rating bands for energy efficiency.

Thermal Performance

Modern 6 star dwellings in Western Australia need very little in the form of heating/cooling. The developer with sustainability in mind will provide only ceiling fans for cooling and renewable biomass pellet heaters for heating. Bio Where air conditioners are provided they should be single split units which can obtain higher efficiencies generally than multi splits. A COP/EER of 5 is exemplary.

Tri-generation, deep geothermal and shallow ground source heat pumps can also be appropriate in very large developments with high demands such as precincts with swimming pools. However they entail very high outgoing capital costs and the environmental benefit should be considered carefully against other technologies.

Swimming Pools

Most importantly swimming pools should be appropriate for the size of the development. Proportionally 50m2 pool shared amongst 100 dwellings will have 100x fewer impacts per dwelling than the same size pool provided for a single dwelling. Where pools are installed they should ideally be naturally heated through ambient air and install pool covers that contain the heat when the pool is not in use. Typically including a pool cover which can operate automatically or manually for 8hrs per day during the pools closed hours has a 28% saving in the pools heating energy demand. Pool pumps efficiency should also be considered carefully, high-efficiency pool pumps of up to 9 stars MEPs rating are currently available on the market.

 Hot Water

Alongside solar thermal technology and low flow shower heads, an opportunity exists to warm the inlet temperature of the water by using a heat exchanger. Water exiting apartments in the sewerage drains will have a higher temperature than the normal inlet temperature of water coming into the building from the mains, particularly in winter.  By passing the inlet water over the warmer outgoing water, the temperature can be increased. A 5% reduction in energy demand of the hot water system can be achieved.

For communal systems there will be significant heat losses in the pipe carrying the hot water around the building as well as from the individual water storage tanks. Based on the conservative assumptions of a 25mm pipe with 25mm of insulation (125mm total diameter) the heat losses are estimated to increase the hot water demand by 10%. Correctly installed 50mm pipework insulation could therefore reduce the losses through hot water pipe by approximately 5%.

 

eTool

The door is always open at eTool for questions surrounding design decisions. If a project is in concept phase we are happy to sit down for an hour and discuss potential strategies and targets. Full targeting sessions are also available at low cost to determine more accurately the costs involved in achieving design aspirations. Following this our full LCA will provide the most detailed environmental assessment available.