Homework Help

Solve the following problem.The PasivHaus standard for low energy building requires...

user profile pic

adolphina | Student, Grade 9 | Honors

Posted December 4, 2010 at 11:46 PM via web

dislike 1 like

Solve the following problem.

The PasivHaus standard for low energy building requires that the U-values of all outer shell materials be no more than 0.15 W/ m^2*K.
If the area of a PassivHaus standard wall is 18 m^2, how much energy En flows through the wall over a week if the inside temperature is 10 ℃ warmer than the outside?

1 Answer | Add Yours

Top Answer

user profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted December 5, 2010 at 11:10 AM (Answer #1)

dislike 0 like

I believe you want to know the energy that flows through a PasivHaus standard wall.

Now the U-value of the standard PasivHaus low energy building for all outer shell material is to be less than 0.15 W/m^2*K.

So the rate of energy flowing out can be a maximum of 0.15 W/m^2*K. The standard area of the wall is 18 m^2. The temperature difference inside and outside the house is 10 degree C or 10 K.

Therefore the rate of flow of energy is 0.15*18*10 W

= 27 W.

In a week there are 24*7= 168 hr.

Therefore the energy flowing through the building is 168*27 W*hr

= 4536 W*hr

= 45.36 kW*hr.

The required energy flow over the week is equal to 45.36 kW*hr.

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes