In this tutorial we're going to briefly go over how you define walls and doors in the Zebra model. Doors in this context only applies to opaque doors; if you have doors with glazing you should define those in the glazing sheet.

In the walls and doors sheet we can define a list of wall/door elements. For each element we're looking to define a name, and orientation from north, U-value, shading from sun and the gross area. The gross area is the area of the window/door element, including any windows within it. When we subsequently look at the glazing sheet we will see we can assign the glazing to these wall/door element. These will be deducted from the gross area of the walls/doors to obtain the net area, which is the area through which heat will be lost. The reason for this system is to make it easier to adjust window areas, without having to change the areas in multiple places.

Once we have input these values the spreadsheet will calculate the heat loss as the product of the U-value, the net area, and the temperature difference.

Once we've defined some elements we will see a summary of the space heating demand, and the space cooling demand. These are the the losses through these elements we've defined. The first part of the summary is a breakdown by element. The second part is a breakdown over the months of the year.

That's actually everything you need to do to define our walls and doors. If we go into a higher complexity level we will just see a more detailed breakdown of how the values have been calculated, and also have the ability to override some default values relating to the solar gains through the opaque fabric.