Wednesday, 7 February 2018

Teaching Low Energy Building: Final Questions-part one

Each week ​I've been adding questions on the content of each lesson to an online learner management system called Module. Here are the​ first three​ questions for the final lessons. I'll post the answers next week!

1.​ ​What is the top priority for a low-energy building?

Select one:

​2. ​(This question follows the question in the Windows 2.0 quiz)

You want to build a small house with a heating load under 25 kWh/m2a. The house is 35 square metres, so you want to use less than 875 kWh per year. The wall and roof area of the house is 100 square metres. You want 4 square metres of windows. The house is in Matsumoto where the annual heating demand (G) is 80 kKh (kilo kelvin hours).

If you use U 2.3 windows, they will lose 736 kWh per year. So the rest of the house must lose less than 139 kWh (875-736). The U value of the walls must be 0.017. (U = Q / A G.) Using nano-porous super-insulation material (k=0.015 Wm/K), these walls would be around 90 centimetres thick!

If you use the other windows, how many times smaller are the U values for the wall?

In other words, how much thinner can the walls be?
U 1.7 Double, low e, argon, wood frames
U 1.3 Triple, low e argon, PVC frames
U 0.8 Triple, krypton, insulated wood frames
What about the single pane windows (U 6)?
​3. The teachers' room has a coffee maker. Usually five days a week, twice a day, someone makes coffee in the break time, has one cup. Then for 90 minutes the rest of the coffee sits in the pot, with the heater on, until the next lesson has finished.