Week 3 - Weather Boundary Conditions

Question 1

List the weather parameters that influence a building’s energy consumption and environmental conditions.

Answer 1

1. dry and wet bulb temperature (degrees Celcius);
2. wind speed and direction (m/s ; ° from N);
3. global and diffuse solar radiation (W/m^2);
4. net longwave radiation (W/m^2);
5. relative humidity (%)

Question 2

Identify two major issues that must be addressed when selecting weather data for a particular site.

Answer 2

1. selection of representative extreme and typical conditions (to test operational robustness); and
2. adequate representation of overall severity (to test whole life performance).

Question 3

Select three different energy systems and state for each the relative importance of the principal weather parameters.

Answer 3

1. In buildings, temperature dominates energy demand because it dictates heat losses/gains through conduction and air leakage.
2. Solar radiation is next in importance, especially in designs embodying passive solar elements.
3. Where air conditioning is employed relative humidity will be a major factor.

Question 4

Most weather stations are located at airports. What are the potential problems when recorded data is used to design a building including renewable energy technologies in the city centre?

Answer 4

The data will not adequately represent the heat island effect of cities or the local micro-climatic impacts of urban forms (solar shading, wind attenuation etc.).