- This topic has 3 replies, 4 voices, and was last updated 3 years, 3 months ago by Richard Haynes.
City of Vincent LCA Requirements
We are currently working on a multi-unit residential development project which requires to meet City of Vincent (Western Australia) requirements of 50% GWP reduction and 25% FW reduction.
In the initial analysis we did for this project we did not consider the 20% Factor of Safety requirement as it was not mentioned in the CoV requirements. We suggested few improvements to the design which would achieve the CoV requirements based on comparison we did using eTool.
The recommendations we used in our analysis are more practical and used real world figures (for instance, HAVC efficiency used in our analysis is EER-3.7 and COP-3.9 in comparison to the recommendations in eTool of 4.4 which is not a practical figure to achieve in terms of real world HVAC system performance).
Would you be able to explain the reason behind the use of the 20% FOS for Target setting exercise, is it;
To compensate for the accuracy of recommendations used in the eTool software, OR;
To give flexibility to project with recommendations that will be implemented during construction, OR;
Any other reason
The project is now in DD stage and the owner wants to finalize the recommendations.
As we have only considered practical and accurate recommendations for the project without being too ambitious would eTool accept a lower FOS for the project?
Hi and thanks for the question.
Firstly, the 20% factor of safety is only required for target setting studies (so if you’re conducting a full LCA it’s not required). This was a concession by the City of Vincent. The policy is pretty clear that the study should meet the EN15978 requirements for an LCA, and a Target Setting (using whole building templates) clearly doesn’t comply in terms of data quality. The city did however see that the Target Setting offered a lower cost option for developers at the Development Approval stage and was hence attractive. They recognised the accuracy issues with target settings and hence agreed that a factor of safety is required. It’s not an eTool directive, rather a city of vincent directive. We gave them the idea as we used to apply the factor of safety anyway as we felt it was good practice. Essentially we agreed to support the pathway as although eTool will loose out commercially (it’s lower cost to deliver target settings than full LCA studies) the planet wins (as the developer is agreeing to over-perform a bit).
It should also be noted that the factor of safety is not just for assessing the accuracy of the strategy itself but also giving the stakeholders a buffer in case the actually base design modelling is not accurate.
So in summary, if you’re conducting a full LCA, not factor of safety required and it’s not an eTool requirement so to ask for a concession you’d need to chat to the City of Vincent.
It’s really good that you’ve scrutinised the recommendation template. These are just suggested ways of documenting the strategies and we encourage users to edit as necessary. Regarding the availability of high efficiency Aircons, I am not sure if you project is residential or commercial.
If it’s resi there’s plenty of split system units that meet that EER / COP hurdle. See this sheet I prepared from a current download of MEPS Registered Air Conditioners (the summary filters for Available Units and sort by COP / EER). There’s well over 100 products products that meet the hurdle set in the eTool Recommendation template offered by major brands such as Daikin, Mitsubishi, LG and Toshiba (and according to the list nearly 300 products in total). If it’s commercial property, using a packaged cooling tower would probably deliver a cooling COP of 6 or more.
I hope that helps.
Hi Richard, thanks for the reply.
As I mentioned in the first line of the question this is a multi-unit residential building.
All models you have referred from MEPS register are single split units. Can you give us an example of a multi-unit residential project where single split units are used? We are very interested to see how the project managed the number of condenser units in the project. Please note when single split units are used a three bedroom apartment will have four separate indoor units (3 for bedrooms and 1 for living) and same number of condenser units attached to them.Typical arrangement for a similar project would be Multi-Split.
I’ve updated the sheet to filter for multi-splits. We have however worked on a number of developments where they opted for one split system for the whole apartment. I’m not an expert on HVAC but I believe MEPS / Australian Standards only introduced the standards for multi splits in 2013 (prior to that multi-splits were not covered) so no doubt there’s some lag there in the testing of new units. I’ve updated the sheet with the latest download from the MEPS database and filtered for multi-splits. There’s over 20 that meet the requirements. I checked a few out and they seem pretty typical in size and price.
Historically we haven ever had significant push back from mechanical teams when specifying this. Ocassionally they’ve come back and dropped the hurdle a little and we’ve just updated the LCA. There was some confusion early on when MEPS didn’t cover multi-splits however this was overcome by reaching out to manufacturers and specifying the minimum COP / EER requirements. Daikin were usually most responsive and it so happened that most of the mechanical consultants we encountered preferred Daikin. So quite often they were complying with the recommendation without even actually knowing it.
You must be logged in to reply to this topic.