Steady State vs Dynamic Simulation – The financial implications

By Simon Brown

If someone asked you to perform some sort of analysis where 12 sets of data were required and this was to be compared with another analysis where 8760 sets of data had been used, which would you think the more accurate – the second one, right?

You might be wondering why I’ve used these figures.

12 relates to the number of months in a year and 8760 is the number of hours in the year.

You might now see where this is going.

How can you perform an accurate energy analysis and energy CO2 footprint of a building using only monthly data? You can’t, yet many of you are still using inaccurate steady state tools which, likely as not, fails the building as far as the BER vs TER comparisons are concerned to meet Part L.

There is now a move afoot to reduce carbon emissions by 23% over the coming few years to make up for the relaxation of the expectation of the carbon reductions, after the financial crisis which began in 2008.

Now there is going to be a real drive towards the reduction in CO2 and to put it bluntly, steady state methods will no longer cut the mustard when it comes to energy analysis and CO2 foot printing which form part of the Part L.  This may still be OK for plant sizing but not detailed legislative analysis.

So what effect does this have on you, the contractor or consultant who are tasked to perform these tasks as part of the building procurement process?

By continuing to use these outmoded methods you are going to find it tougher and tougher to pass without recourse to renewables and yes, you’ve guessed it, renewables cost money, and yes this makes you less competitive (not to mention the man in the diesel van having to install them and the CO2 footprint of their production in the first place!). Your competition may have used simulation and don’t require expensive renewables to affect a pass. Do you know who you are bidding against and whether they can undercut you, as they have effectively done a more detailed analysis?

The temptation to use free tools is understandable, but free tools are usually free for a reason as they tend to use generic open source algorithms that don’t relate to the specifics of the task. There are plenty out there that will show you lots of pretty pictures of shadowing of buildings but most won’t tell you about whether you have failed Criterion 3, TM52 adaptive overcooling test or the 2016 BB101 for Schools prescriptive program where more complex cross flow ventilation methods are recommended…try undertaking those calculations with generic or inaccurate tools!

So next time you are having to go down the renewables route using free issue or even paid for tools that are inaccurate, consider what the competition might be doing. Who knows if you go down the level 5 route you might be able to expand the business and undertake energy rating of buildings to make sure they are better than an F or G rating, so they can be leased and bought, or improved or even sold off after a cost benefit analysis.

Or more significantly you might want to consider not paying £5000 per model you “farm” out to a specialist who will spend a day modelling a building (not bad for a day’s work). You could diversify your business and become more competitive…..just a thought.