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Hi Leigh
Unless I have misunderstood it does sound like this is to ambient. I think the Rse is 0.17 according to AECB Carbonlite Building Science course manual but if you have insulation in the floor then the Rse won't have much effect on the U value result.
Cheers
Nick
Hi Will
The hair removal cream looks great but I'm struggling with the other site. Pure prejudice but when I see the phrase “incredibly efficient” on a website my alarm bells ring.
I would have given this more time but I just wasted an hour reading Amazon reviews 🙂
Cheers
Nick
Doesn't sound great, as you say a condensation risk plus rain tracking under the frame if I am picturing the detail correctly.
Not all thermally broken ally windows are as thermally broken as they might be so that might be more of a bridge. Also not sure how lead and ally behave in terms of corrosion, I know lead and galv is a big issue.
Not wanting to give you more to worry about just hoping others can answer.
Nick
Worth pointing out that the benefit of mass is modest and that it doesn't 'slow down' the escape of heat as some claim!!
No, I use Therm, in XP in Parallels on Mac.
No problem taking screenshots from Mac side and pasting results into XLS.
Some good resources on Warm's web site and the training is very good.
http://www.peterwarm.co.uk/resources/downloads/
Nick
The main target is the space heating of 15kWh/(m2.a) (or 10W/m2 peak heat demand).
This is calculated according to PHPP with Passivhaus assumptions for gains etc.
Please see the document claiming the Passivhaus Standard which can be downloaded from the Passivhaus Trust Website.
There are no prescribed elemental U values except for windows (climate specific) and that is for comfort. However you will need very good U values (0.15 or better in the UK is typical) to meet the target for most building types, especially dwellings.
The 120kWh/m2 if total primary energy value.
Same for Carbonlite, I can't help with CSH.
Nick
Hi Kate
upgrading the building is likely to result in increased internal temps not reduced so the degree days will increase.
Crudely the average temperature difference for a given month x number of hours summed for all heating season.
The degree hours I use are generated by PHPP so I don't know the finer details of generating degree hours from weather data.
HTH
Nick
Rachel
Yes need to model both and associated ducts.
PHPP 7 includes a multivent sheet but I have not used it yet. Before that existed we made a sheet to average based on flow per unit. Gives a total vent rate and average efficiency for vent sheet.
Nick
The mouldy filter avoidance comes from the PHI. All the Swedes I have talked to deny it is a problem but we don't want to take risks at school scale project.
Re controlling night vents I'm all for designing out BMS but does need a little computation to do properly. With BMS you look at outdoor temp and open high level vents when inside is higher that a set point and outside is cooler. Also loos at wind speed and if no louvres, rain. If you just open when too hot in the space I don't know that it would be any worse than with BMS that is shutting the windows when the toilet light goes on 🙂
With the PH schools we had a period of clear skies in spring where it was hot by day and cold at night. Unfortunately the BMS was programmed to keep windows shut at night if below 10C (or whatever)! Meant the building got warmer and warmer despite plenty of lovely night cooling potential.
Sorted now but the more complexity, the harder it is to get right the first time. Never thought building would overheat if too cold! Had same with a frost coil coming on in the kitchen vent because freezing outside, was the only day it got too warm in the kitchen!
Good luck!
Bob
I have emailed you a brochure on vents designed for MEV but have not used them. FrischLuftKomfort might show up in Google.
Unless Alan or others disagree, I'd be with Mark on pulling the air thru' the fabric, need a few Pa resistance so that wind and stack don't dominate.
Nick
The engineer will specify this to suit.
Nick
7 August 2012 at 6:42 am in reply to: Re: Re: Embrace BIM, it’s a great tool for sustainable design #38628I hate to direct people away from the AECB forum but BIM boys and girls seem to reside on Twitter! Try Elrond there. Revit is what they use and is the only software I have seen in action. Quite a learning curve especially for sub consultants who may only have a single job in BIM at present. Thankfully I only need to get info out of the model and don't need to draw in it.
Certainly a very powerful tool for big complex buildings such as schools and offices. My concern is that it encourages more complexity. It is difficult enough to build something that has been designed in 2D with pencil. Being able to design complex shapes and avoid services and structure clashing could be a licence for gratuitous complexity.
Thankfully Elrond doesn't use it that way!
7 August 2012 at 6:32 am in reply to: Re: Re: Tunnel vision in the Sustainable Building Sector: time for a new way forward! #38570Danny, I also didn't respond and not because of tunnel vision.
On the energy autonomy angle you might like to comment on my paper and blog post, Zero Inteligence which tries to make very specific points that you can challenge.
http://www.bdonline.co.uk/comment/blogs/the-sustainability-blog/
Free to register and comment.
There is also a post on the AECB conference which touches on the wider issues you raise.
Nick
Very good Dave!!
I believe there are examples in Germany but will be larger buildings or terraces to get a very favourable form factor. Whilst Passivhaus is not heavily reliant on solar gain it is part of the energy ballance.
With phpp it it very quick to get an answer to such questions for a specific site and building.
Another concern woukd be how to get the daylight without lots of east and west glazing (winter heat loss and summer overheating issue) or excess North glazing (lots of heat loss and some summer overheating risk from late pm sun.
Passivhaus asside, not ideal.
Just visited Mike Whitfield's latest passivhaus project which has road to South. Still went for the windows and will use internal blinds. Nice to have that winter sun even if there is no nice view that side.
Hi Phil
Hopefully Alan will chip in rather than me confusing things but yes, over ventilating is a problem for air quality, energy use, noise and cost.
15m3/ pupil/h seems fine for classrooms and for the Passivhaus schools we try and follow something close to a cascade approach with air supplied to classrooms and offices and extracted from loos etc. hall supplied from hub air by fan when needed.
One issue with very variable use (which you hint at) is that the fans don't turn down below a certain minimum rate without stopping so may need 2 units or timer control so not on continuously at low occupancy. For the schools we turn the vent off at night but have the complication of a filter drying cycle to avoid mouldy filter risk.
Try and KISS!
Nick
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