Can anyone point me in the right direction for having my design modelled for its solar passivity? I'd like to have it accurately modelled before we finalise design for costing and manufacture to make sure I've not made any glaring errors.
TIA
Browse Forums Eco Living 1 Jul 31, 2010 9:33 pm Can anyone point me in the right direction for having my design modelled for its solar passivity? I'd like to have it accurately modelled before we finalise design for costing and manufacture to make sure I've not made any glaring errors. TIA Re: Computer modelling 2Jul 31, 2010 11:38 pm I am not terribly impressed by the local modeling software. We used AccuRate and I don't think it picked up some issues with our glazing:mass ratios. We tried different permutations but it failed to demonstrate any differences. I am not sure if it is a problem with the software or the operator. Your best bet is to stick with the general recommendations for orientation, shading and thermal mass. The most important lesson that we learnt is that each room in the house should be designed as in independent area based on these numbers rather than as a total. Re: Computer modelling 4Aug 01, 2010 9:23 am dymonite69 I am not terribly impressed by the local modeling software. We used AccuRate and I don't think it picked up some issues with our glazing:mass ratios. We tried different permutations but it failed to demonstrate any differences. I am not sure if it is a problem with the software or the operator. Your best bet is to stick with the general recommendations for orientation, shading and thermal mass. The most important lesson that we learnt is that each room in the house should be designed as in independent area based on these numbers rather than as a total. I agree... but after orientation, insulation is number 1, and double glazing is the vast majority of the insulation issue once you have done the wall and ceiling batts. From the ABC Quote: House energy star ratings 'unreliable' By Adrienne Francis Posted Sat Jul 31, 2010 11:14am AEST The HIA says different software produced vastly different ratings for the same new homes. The Housing Industry Association (HIA) has discredited the energy star rating system used to assess new houses. The HIA assessed the energy rating of an identical home in every capital city last year using three different energy rating programs, designed by private companies and endorsed by the Federal Government. The software programs are meant to give consistent results but instead produced vastly different ratings for the same new homes. Kristin Tomkins from the HIA is calling on the Government to urgently review the programs. "The worst result we found was in Brisbane. A two-storey house in Brisbane had a 3.2 star difference between the highest and the lowest score," she said. "If we are looking to significantly reduce our greenhouse gas emissions from the housing sector, consumers and builders need to have confidence." The HIA says the Government would need to allocate hundreds of thousands of dollars to correct the schemes. "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: Computer modelling 5Aug 01, 2010 9:59 am Yes. Forgot the important element of insulation. However the problem with the star ratings and codes is that it is only considers this with little regard for the others. e.g. McMansions with huge west facing windows and no eaves (put plenty of batts!!!) Re: Computer modelling 6Aug 01, 2010 10:05 am dymonite69 Yes. Forgot the important element of insulation. However the problem with the star ratings and codes is that it is only considers this with little regard for the others. e.g. McMansions with huge west facing windows and no eaves (put plenty of batts!!!) Orientation is paramount in all the software. And if you input lots of "what-ifs", you can model various windows on different facades. But in the end it's only software,and it only contains the parameters that someone else has programmed. But most of all, according to the HIA, the software is not accurate... "ECOECO" At 'EcoEco', we design windows, we design the best windows, we do it for you, so that when you’re happy we are happy. Tel. 1800 326 326 Re: Computer modelling 7Aug 01, 2010 11:08 am Cheers Dymo and Ed. I had actually read that article but hadn't connected the dots that this would be the modelling done, I had somehow thought that there would be different modelling for star ratings and the detail I was after OK so a little clarification if I may Quote: dymonite69 wrote: RBV is definitely enough mass in addition to the slab. The conventional rule is 6 m2 mass area to 1m2 north glazed area. Is this figure for total thermal mass in the building (or each room as per your input above dymo) or only that which is in direct path of sunlight? By our rough calcs we are just under this ratio for either total slab or RBV walls alone, so would it be too much thermal mass if it were around double that? Re: Computer modelling 8Aug 01, 2010 1:07 pm That's sun exposed mass. The mass cannot be covered by insulating materials like carpet, lino or cork. The most economical thing to do is tweak the window area for the amount of mass you have in each room (rather than trying to change quantity of mass). However, you can increase both in correct proportion. NB the mass should be shaded from sun during summer. Re: Computer modelling 9Aug 01, 2010 3:09 pm Cheers Dymo we'll re-do our sums and see if it all works out ok |