Building enveloppe system - Donatien

Submitted By
Donatien Delmon

The base scenario with R38 walls and an operating schedule of 12/5 gives the following results:


I wondered for a long time why my results were so bad compared to others. I realized it must be because my project is based in France which has a way colder climate than in California.

This is why I did not manage to get as low as 54 kBtu/ft²/yr as requested. Even by putting the most efficient windows and wall materials on the whole building, I was only able to get to the following results:


Sunshading havin almost no impact on the efficiency of the building, I did not change the settings. The cost in buildability would not be worth the tenth of kBtu/ft²/yr it could result in.

Even if the double glass type on west and north facades were good enough for the results, it is easier if all the curtain walls are built in triple glass so I finally chose to put triple glass type for all the facades because of the fair amount of glass essential to my design. I also used 14-inch ICF walls. I finally got the following results:


Adding the best lighting efficiency, the best plug load efficiency as well as using daylights and occupancy control got the consumption as low as 43.4 kBtu/ft²/yr:


Adding the best photovoltaïc options, it only got as low as 41.3:


The question here would be if the emissions for creating the panels are worth the 1 kBtu/ft²/yr or not which might not be the case for a climate such as the one in Paris.

Scenario comparison:


Finally, i would recommend using the following parameters:

South: 57% WWR, Trp LoE

North: 19% WWR, Dbl LoE

West: 10% WWR, Dbl LoE

East: 63% WWR, Trp LoE

Wall construction: 14-inch ICF (might not be as efficient because keeping the old building, would have to improve the insolation)

Lighting efficiency: 0.3W/sf

Daylighting & Occupancy Controls: Both

Plug Load Efficiency: 0.6W/sf

No panels