eToolLCD Expressions

eToolLCD V2 introduced some pretty neat functionality that allows users to enter “expressions” into some fields in a similar way formulas are used in a spreadsheet. This is particularly useful for building operational energy templates, for example, based on building size or occupancy. We have used a third party calculation library to enable this functionality, the list of available operators and functions is available here.

This functionality has dramatically improved the ease at which we can predict operational energy in designs and we’re enjoying using it here at eTool. We will be adding more stored variables as time passes, watch this space. To learn how to utilise this functionality, please get in touch for some training.

We also have a number of variables that relate to the design and can be used in expressions. The list of these is provided below. The default values that are used in library template calculations before loading into a design, or when a variable is left blank. The full list of variables is here:

NameUnitCodeDefault ValueModel LevelCategoryDescription
Annual Data TransmittedTBDT100,000FunctionAttributeAnnual Data Transmitted
Annual Energy GeneratedkWhEG100,000FunctionAttributeAnnual Energy Generated
Annual Energy StoredkWhES1,000,000FunctionAttributeAnnual Energy Stored
Annual Energy TransmittedkWhET1,000,000FunctionAttributeAnnual Energy Transmitted
Annual Freight ThroughputtFT100,000FunctionAttributeAnnual Freight Throughput
Annual Horizontal Infrared RadiationWh/m2Sol_H6,500ProjectAnnual Horizontal Infrared Radiation
Annual Operating HourshrsOH2,000FunctionAttributeAnnual operating hours of the building for its intended functional use.
Annual Passenger Throughput#PT60,000FunctionAttributeAnnual Passenger Throughput
Annual Standard Axles#SA600,000FunctionAttributeAnnual Standard Axles
Annual Throughput Volumem3TV6,000FunctionAttributeAnnual Throughput Volume
Artificially Lit Aream2ALA1,200FunctionServicesArea artificially lit
Average Ambient Temperature Whilst CoolingDegrees CACT35DesignHiddenAverage ambient temperature whilst cooling weighted for heating times and loads
Average Ambient Temperature Whilst HeatingDegrees CAHT5DesignHiddenAverage ambient temperature whilst heating weighted for heating times and loads
Average Daytime Occupancyhrs/dayDTO8DesignHiddenAverage daytime occupancy hours for the building
Average Nighttime Occupancyhrs/dayNTO8DesignHiddenAverage nighttime occupancy hours for the building
Average water Inlet TemperatureDegrees CIWT15ProjectAverage Water Inlet Temperature
Bedrooms#BR3FunctionAttributeNumber of bedrooms
Beds#BE25FunctionAttributeBeds
Cooling LoadMJ/m2/AnnumCL900FunctionServicesCooling load required of mechanical HVAC plant to control building temperature
Data Storage CapacityTBDS10,000FunctionAttributeData Storage Capacity
Default Indoor Illumination RequirementLxLTA900FunctionServicesDefault illumination intensity required in the building
Direct Solar RadiationWh/m2Sol_D7,000ProjectDirect Solar Radiation
Durability Life ExpectancyyearsDLE100DesignDurability life expectancy which does not account for redevelopment pressure
Dwellings#DW1FunctionAttributeNumber of dwellings (or tenancies) in the building
Energy Monitoring Adjustment Factor0%EMAF1ProjectEnergy monitoring adjustment factor for consumption rates
Expected OccupantsyearsO10DesignExpected occupancy of the building
Expected Service LifeyearsLE50DesignExpected Service Life
Fully Enclosed Covered Aream2FECA1,200FunctionAreaThe sum of all such areas at all building floor levels, including basements (except unexcavated portions), floored roof spaces and attics, garages, penthouses, enclosed porches and attached enclosed covered ways alongside buildings
Gross Floor Aream2GFA1,400FunctionAreaThe sum of the Fully Enclosed Covered Area and Unenclosed Covered Area as defined
Heating LoadMJ/m2/AnnumHL900FunctionServicesHeating load required of mechanical HVAC plant to control building temperature
Indoor thermostat set point (Summer)Degrees CICT24DesignHiddenIndoor thermostat set point during summer
Indoor thermostat set point (winter)Degrees CIHT20DesignHiddenIndoor thermostat set point during winter
Land Aream2LA2,000ProjectLand associated with the building project (footprint of building, parking and landscaping)
LengthkmLN10FunctionAttributeLength
Life Cycle Bed - Nights#LCBNCalculatedFunctionAttributeLife Cycle Bed - Nights
Life Cycle Data TransmittedTBLCDTCalculatedFunctionAttributeLife Cycle Data Transmitted
Life Cycle Energy GeneratedkWhLCEGCalculatedFunctionAttributeLife Cycle Energy Generated
Life Cycle Energy StoredkWhLCESCalculatedFunctionAttributeLife Cycle Energy Stored
Life Cycle Energy TransmittedkWhLCETCalculatedFunctionAttributeLife Cycle Energy Transmitted
Life Cycle Freight Distancet.kmsLCFDCalculatedFunctionAttributeLife Cycle Freight kms
Life Cycle Freight ThroughputtLCFTCalculatedFunctionAttributeLife Cycle Freight Throughput
Life Cycle Occupant HourshrsLCOHCalculatedFunctionAttributeLife cycle operating hours of the building for its intended functional use.
Life Cycle Passenger Distance#.kmsLCPDCalculatedFunctionAttributeLife Cycle Passenger kms
Life Cycle Passenger Throughput#LCPTCalculatedFunctionAttributeLife Cycle Passenger Throughput
Life Cycle Standard Axles#LCSACalculatedFunctionAttributeLife Cycle Standard Axles
Life Cycle Throughput Volumem3LCTVCalculatedFunctionAttributeLife Cycle Throughput Volume
Life Cycle Workload Unit Distance#.kmsLCWLUDCalculatedFunctionAttributeLife Cycle Workload Unit kms
Life Cycle Workload Units (1p = 100kg)#LCWLUCalculatedFunctionAttributeLife Cycle Workload Units (1p = 100kg)
Lighting LuxlxLX150FunctionServicesSpeficied light requirements of the lit area
Lighting Runtimehrs / yearLRT2,500FunctionServicesAnnual lamp run time
Mechanical Ventilation Runtimehrs / yearMRT2,500FunctionServicesAnnual operating hours of mechanical ventilation system
Net Lettable Aream2NLA1,000FunctionAreaThe sum of all lettable areas within a commercial type office building
Pavement Aream2PA62,500,000FunctionAttributePavement Area
Project Occupancy#P_O10ProjectOccupancy of the entire project
Storage Volumem3SV2,000FunctionAttributeStorage Volume
Stories#ST1DesignNumber of stories (or levels) in the building
Tenancies#TE1FunctionAttributeNumber of tenancies
Treated Area - Coolingm2CA900FunctionServicesInternal area conditioned by mechanical HVAC plant equipped to cool
Treated Area - Heatingm2HA900FunctionServicesInternal area conditioned by mechanical HVAC plant equipped to heat
Treated Area - Mechanical Ventilationm2MA1,000FunctionServicesInternal area conditioned by mechanical HVAC plant equipped to heat
Unenclosed Covered Aream2UCA200FunctionAreaThe sum of all such area at all building floor levels, including roofed balconies, open verandahs, porches, porticos, attached open covered ways alongside buildings, undercrofts and useable space under buildings, unenclosed access galleries (including ground floor) and any other trafficable covered areas of the building which are not totally enclosed by full height walls
Usable Floor Aream2UFA1,000FunctionAreaFully enclosed building area
Vacancy Rate0%VR0FunctionAttributeVacancy Rate
Vehicle Spaces#VS40FunctionAttributeVehicle Spaces
Work Stations#WS2FunctionAttributeNumber of workspaces and/or bedrooms in the building

eTool Residential Benchmark For Australia

Before getting into the nitty gritty, it’s important to understand the purpose of the eTool benchmarks, which is:

  • Establish a common measuring stick against which all projects are assessed so that any report is comparable to another (for the same type of project).
  • Create a starting point, or “average, business as usual case” from which to measure improvements.

The benchmarks are not an average of existing stock but rather an average of new stock. Hence any efficiency requirements etc in the Building Codes etc are taken into account. When comparing to the benchmark, the target is pretty simple. Effectively Australia has to drop it’s GHG emissions by about 90-95% on a per capita basis for us to become sustainable global citizens. With this in mind, what we should be trying to do is drop our building’s emissions by 95% against the benchmark to ensure the building is stabilising the climate.

Creating the business as usual benchmark is pretty complex. For residential buildings in Australia there is a broad density mix from detached through to apartments. This is the latest breakdown of the new dwellings density mix in Australia (from ABS) over the last two years:

DetachedSemi DetachedLow Rise ApartmentsHigh Rise Apartments
Proportion of New Dwellings61%13%7%19%

For each of these density types, eTool have formulated a BCA code compliant building. We have then created a nominal statistical mix of  floor areas to match the average new dwelling size in Australia (214m2). In this way we come up with a “dwelling” that is a mix of densities and matches the size of the average Australian dwelling.

A similar approach is taken for operational energy. In this case we first research the most up to date residential energy estimates for Australia.  This data comes from ABARE Energy in Australia 2012. It gives us guidance on the total energy used per household (existing housing stock) in Australia and also the fuel mix split (electricity, gas, wood etc). We then use other end use percentage estimates to determine where this energy is being used in the dwellings.  The most commonly quoted breakdown of household energy use in Australia is from the “Your Home Technical Manual” which is actually a reference to the “Energy Use in the Australian Residential Sector, 2008”.  This report is commonly referred to as the “Base line report”.  This report itself actually states:

The study identified a paucity of end-use data for residential energy use in Australia, particularly in regional areas. Some of the appliance energy consumption estimates used in this study rely on research that is 15 years old or, alternatively, on work undertaken in New Zealand. 

The study recommends an comprehensive end use energy monitoring program which we believe is being undertaken. Until the results are out we’re a feeling our way in the dark a little.  Not withstanding this, the study is useful to guide the decisions about where we’re using our energy. To verify the Base Line Report figures we also took some state government studies (eg Sustainable Energy Development Office in WA) and statistics from other countries (notably the BRANZ HEET study and also stats from the US). The largest unexplained discrepancy seems to be in the estimates for heating demand.

The Base Line Report suggests that 38% of total end use energy in Australia homes is dedicated to heating and cooling purposes.  This seems very high given the following facts:

  • The comprehensive HEET study from BRANZ in New Zealand (a much colder climate, and one dominated by heating requirements) only calculated 34% of end use energy dedicated to thermal performance.
  • The WA SEDO estimate for thermal comfort energy demand is also much less, hence it’s hard to believe the additional demand is due to cooling.
  • A large percentage of Australia’s population (Perth, Sydney and Brisbane) all live in quite mild or warm climates where heating would not make up more than 50% of the thermal control energy demand (and less still of the actual end use energy demand)
  • Heating is the most end use energy intensive thermal comfort mode as cooling typically utilises either apparent cooling methods (evaporative or fans) or heat pumps, both of which have effective Coefficient’s of Performance of 2.5 or more. This means for every one unit of energy input, 2.5 units (or more) of heat is dissipated of pumped from the dwelling when cooling. Heating on the other hand requires more energy than the actual heat load demand theoretically required to heat a space (or at least the same amount). This is mainly due to flue losses.

The high estimate in the Base Line Report may be linked back to the ABARE Energy stats which are also questionable. The Energy in Australia 2012 document from ABARE gives a biomass figure for residential energy use that equates to 6280MJ / household /annum.  When this is calculated in terms of mass of wood, it works out at 400kg of timber per household in Australia.  Even if one in every 5 houses (studies suggest it’s more like one in every 10) is using a wood heater that was their primary source of heat, that’s 2t of wood per annum they would need to be burning in order for the ABARE data to reconcile. To give you an idea, an average small box trailer full of wood is about 250kg. We’re not convinced there’s 2 million households in Australia receiving 8 trailers of wood per annum to heat their homes. The BRANZ HEET study further supports the proposition that ABARE have overestimated biomass consumption in the Australian residential sector.  BRANZ calculated that each wood heater uses 4,500kWh (one tonne) of wood per annum.

Without making any adjustments to either the end use demand figures, or the top down supply figures the numbers don’t reconcile very well. For example, trying to “fit” the biomass, gas and LPG energy into the end use break down “squeezes” electricity out of the hot water and space heating categories. There simply isn’t enough low grade heat requirements in dwellings to account for all the biomass. However, when we aligned the biomass use predictions with BRANZ, and adjusted the demand figures to better match some of the competing studies we got good reconciliation.

This also supports the total residential demand estimate in the Base Line Report which is quite a bit lower than the ABARE stats.

Once we knew the amount of energy the existing housing stock were using, we then determine how this would differ in new dwellings.  Some energy use would remain pretty static (eg appliance use and refrigeration). Lighting, hot water and heating and cooling have relatively new BCA code requirements focussed on energy efficiency. For these end categories appropriate adjustments were made to account for the newer technologies and associated demand.

Heating and Cooling (Thermal Control)

The heating and cooling energy requirements are the most complex, as there are very few stats on what equipment is being deployed in new houses. The NatHERS system does help this situation and we make an estimate of the deployment of heating and cooling technologies in the current housing stock as follows:

  1. Estimate the heating verse cooling loads for buildings in the top 20 populous NatHERs climate zones (85% of Australia’s population). This works out to be 60% heating and 40% cooling.  
  2. Estimate the efficiency of each type of heating and cooling technology
  3. Estimate the deployment of each type of heating and cooling technology
  4. Adjust estimates such that total energy consumption matches our adjusted ABARE figures and the split in thermal demand matches the NatHERs weighted average for Australia

This then informs our decisions about what people are likely to choose for new houses.  The summary is found in the following tables:

Electric Heat PumpElectric Fans or Evaporative Coolers
Existing Stock Cooling Demand50%50%
New Housing Stock Cooling Demand60%40%

Electric Heat PumpElectric RadiatorsGas FluedGas Internal HeaterWood Heaters
Existing Stock Heating Demand20%10%17%51%2%
New Housing Stock Heating Demand35%0%20%40%5%

For each major BCA climate zone or population centre then simply divide the NatHERs energy demand estimates for a 6 star dwelling for the building between these categories and apply appropriate efficiency or COP figures to determine what the end use energy demand will be.

Hot Water

The building codes have now banned the use of electric resistance storage hot water systems in all residential buildings apart from class 2 building (strata buildings). Some state governments also discourage the use of electric heaters in class 2 buildings. This has led to a huge shift from electric storage hot water heaters to gas, solar, and heat pump units. This is a great thing for reducing the carbon intensity of the delivered hot water to dwellings (see more explanation on hot water fuel types here).

Using the same reconciling procedure between the end use energy estimates and the adjusted ABARE data we get the following mix of fuel uses for meeting demand in Australian existing housing stock:

Fuel Contribution to Water Heating Demand of Existing StockFuel Contribution to Assumed Water Heating Demand of New Stock
Natural Gas and LPG77%79%
Electric15%13%
Solar8%8%

Note, this doesn’t imply that 77% of water heaters are gas fired, it implies that 77% of energy used by water heaters is gas. The difference is that gas water heaters have lower efficiencies than electric resistance heaters (99%) or heat pumps (approximately 270%). With a gas water heater, depending on the age of the heater, it may be as low as 50%, and won’t get much better than 85%. So the mix of heaters installed in existing buildings is actually more slanted towards electric.

New buildings will tend more towards gas due to the current BCA requirements. With this in mind, we’ve used the figures in the right hand column for the split in fuel use for new dwellings.

eTool V2 is here!

eTool V2 was dreamed up even before we released V1, I think the idea of continual improvement is ingrained in the eTool psychie! But getting to the point of actually rolling out V2 has been a pretty long process. Our first step of course was to prioritise the improvements which was quite a task.  Although we would love to press the magic button and fulfil the “holy grail” of sustainable design (3D optimisation of thermal performance and embodied impacts of materials) baby steps are required.  We asked you guys what you wanted to see; surveys went out to past clients who we have conducted LCAs for, and also our users (who are growing in number and geographical diversity every day).

The key enhancements that people flagged for us were:

  • More reporting functionality (particularly involving costs)
  • More environmental indicators (not just carbon and energy use)
  • More transparent user interface (simpler, clearer)
  • More templates, materials and equipment options in our libraries

So this is where we’ve been focussing our efforts. If you log into eTool V2, you’ll see many features aimed at tackling the above key enhancements, and we’re not done yet! We will be continuing development on V2  until September.

Here’s a quick summary of what’s been implemented:

  • A better materials categorisation system and over 50 new materials to make selection easier.
  • Ability for materials manufacturers to submit their own materials for listing in eTool LCA.
  • Addition of new environmental impact categories (see this listed in the current release, we’re currently populating the data bases so these will become functional over time).
  • Default costs for all materials, equipment, grids and energy sources. As well as the existing detailed carbon and energy metrics, you now also get an LCA cost estimation by only entering in quantities of materials, equipment run time and operational energy.
  • Financial performance comparison chart for buildings to highlight maintenance and operational cost benefits or excesses.
  • Improved user interface for templates, and allowing “nested” templates for much faster LCA projects.
  • Share LCAs with other users.
  • More transparent and editable distance calculations for materials.
  • Annual energy cost summary.
  • Additional grids (all Australian grids now entered).
  • Expression builder for some fields e.g. you can now build a template for operational energy that takes the number of occupants and fully enclosed building area into consideration within a formula to calculate your energy demand.
  • Improved calculations and coefficients for better accuracy.
  • Ability to calculate operational water consumption.

And what’s still to come before we wind up development in September:

  • More reports!
  • Additional Environmental Impact intensities (e.g. embodied water, toxicity etc)
  • Regional LCI databases (data availability / access pending).
  • Ability to add custom distribution grids.
  • Still more templates, materials, equipment, distribution grids etc.

This article was written by Rich

 

eTool V2 Part 1 Complete

Our first step of course was to prioritise the improvements which was quite a task. Although we would love to press the magic button and fulfil the “holy grail” of sustainable design (3D optimisation of thermal performance and embodied impacts of materials) baby steps are required.

We asked you guys what you wanted to see; surveys went out to past clients who we have conducted LCAs for, and also our users (who are growing in number and geographical diversity every day).

The key enhancements that people flagged for us were:

  • More reporting functionality (particularly involving costs)
  • More environmental indicators (not just carbon and energy use)
  • More transparent user interface (simpler, clearer)
  • More templates, materials and equipment options in our libraries

So this is where we’ve been focussing our efforts.
If you log into eTool V2, you’ll see many features aimed at tackling the above key enhancements, and we’re not done yet! We will be continuing development on V2 until September.

Here’s a quick summary of what’s been implemented:

  • A better materials categorisation system and over 50 new materials to make selection easier.
  • Ability for materials manufacturers to submit their own materials for listing in eTool LCA.
  • Addition of new environmental impact categories (see this listed in the current release, we’re currently populating the data bases so these will become functional over time).
  • Default costs for all materials, equipment, grids and energy sources. As well as the existing detailed carbon and energy metrics, you now also get an LCA cost estimation by only entering in quantities of materials, equipment run time and operational energy.
  • Financial performance comparison chart for buildings to highlight maintenance and operational cost benefits or excesses.
  • Improved user interface for templates, and allowing “nested” templates for much faster LCA projects.
  • Share LCAs with other users.
  • More transparent and editable distance calculations for materials.
  • Annual energy cost summary.
  • Additional grids (all Australian grids now entered).
  • Expression builder for some fields e.g. you can now build a template for operational energy that takes the number of occupants and fully enclosed building area into consideration within a formula to calculate your energy demand.
  • Improved calculations and coefficients for better accuracy.
  • Ability to calculate operational water consumption.

And what’s still to come before we wind up development in September:

  • More reports!
  • Additional Environmental Impact intensities (e.g. embodied water, toxicity etc)
  • Regional LCI databases (data availability / access pending).
  • Ability to add custom distribution grids.
  • Still more templates, materials, equipment, distribution grids etc.

eTool Again Leading Building LCA Software

Since the release of eTool V1 we have been receiving great feedback regarding the software which has enabled us to prioritise how to improve it further.  We have finally begun work on Version 2 which will further cement eTool’s leadership in sustainable design software for the built form.

Once again we have commissioned Phobos Consulting to undertake this work and look forward to the improvements they will be making to the excellent interface they have already developed for eTool.  In the Phobos consulting development team we’re excited to have Jeremy Hadfield back on eTool and welcome Matt Kocaj to the project who is already proving very helpful.

Specifically, we have highlighted for following key areas for improvement:

Functionality:

  • Improved interface to simplify the way designs and templates are edited
  • Default costs for all materials, equipment and energy supply sources to facilitate very easy LCA cost calculations
  • More flexibility for entering custom transport distances (not relying on Australian postcodes)

Accuracy:

  • eTool have hired Ben Rose to conduct a third party verification on the eTool inputs, scope and calculations.  eTool is delighted to be working with Ben who has a wealth of knowledge and huge credibility in the carbon analysis world.  Read more about Ben here
  • Introduction of numerous LCI databases to increase the flexibility of eTool and allow sensitivity analysis of results (between database sources)

Reporting:

  • A one page building performance summary certificate
  • Building cost verse time which will demonstrate financial payback periods for sustainability features
  • Annual energy cost tables (and breakdown into operational energy categories)
  • Sustianibility spider (radar) charts to see performance of other environmental impacts (not just carbon and energy).  We are prioritising toxicity and land use for Version 2 and hope to expand on this dramatically in Version 3 and beyond