Building Envelope

1
Building Envelope
2
Energy Conservation

• House design and orientation
• Lifestyle changes
• Energy efficiency

3
Building Envelope

• In this module, we look at the effect of the
  buildings exterior on heat loss during the
  heating season or heat gain during the cooling
  season.
• Walls, windows, roof, and foundation make up the
  envelope.

4
Space Heating Cooling
We use a mathematical and very simplified view of
the building and its thermal envelope. The
amount of heat (Q) that flows through the walls
depends on the temperature difference between the
inside and the outside, and the area of the walls.
5
Interior temperature

• So the interior temperature is important as well
  as the climate which determines the exterior
  temperature.

6
Insulation

• The heat flow depends on the R-value of walls
  windows and ceiling. R means resistance to flow.
  The bigger the R, the smaller the heat loss (or
  gain)

7
Windows

• Windows have low R-value. Even really good
  windows lets heat flow through.

8
Infiltration

• If there are cracks around windows or doors where
  exterior air can seep or blow in, this can be a
  big heat gain or loss.

9
Energy Efficiency

• We are going to mathematically model a house. If
  you hate math, this is OK. Just hang in there for
  a while. Itll be OK.