Question:


Imagine that you are involved in the design of a building which will be located in a sub-tropical location. The design brief suggests that the building should use so-called `green' technologies as much as possible.
You realize that computer modelling and simulation will be necessary to predict the future performance of the building, however there is no detailed climate data available for the site.

Discuss which outdoor climate parameters will probably be of particular interest for this building, and suggest practical solutions for the data problem.

Sample answers:

When designing a building, it is important to know as much information as possible about the climate at the site. For a building located in a sub-tropical location, certain climate parameters will be of particular interest. These are discussed below.

  1. External air temperature will be of interest as it will affect the heating and cooling requirements of the building. It should also allow decisions to be made as to the viability of natural ventilation or whether mechanical ventilation and air conditioning are necessary to maintain occupant thermal comfort. The temperature may also influence the choice of building fabric. For example, it may be required to prevent rapid heat fluctuations and promote heat storage.
  2. The intensity of incident solar radiation will be of interest to allow investigations into the use of either passive or active solar technology. This will allow problems such as overheating to be considered in addition to determining potential energy savings over conventional systems. Obviously, building orientation may be influenced in order to optimise incident solar radiation.
  3. To determine the possibilities of utilising natural light instead of artificial light, the daylight hours will be of importance. Again, building orientation may be influenced to optimise incoming daylight.
  4. Humidity levels may be monitored to identify periods of high temperature and high humidity which may occur in sub-tropical locations. These conditions can have a detrimental effect on occupant thermal comfort and need to be avoided.


The amount of precipitation and prevalent wind speed and direction may influence choice of materials, building orientation etc. but they are unlikely to be of any special significance in a sub-tropical climate.
If there was a lack of climate data available for the site then obviously computer modelling and simulation of the building would be difficult. However, there are some ways in which this problem could be overcome.

  1. Climate data from another area experiencing sub-tropical conditions could be utilised to approximate the climate at the site.
  2. The designers could create their own climate data based on meteorologists estimates for the site and considerations of other climates in a similar location.
  3. The actual climate at the site could be monitored and readings taken. However, this is unlikely to prove viable due to the time required for such a process.


Once the designers have acquired climatic data for the site, they will have to use it carefully as it will only serve as an approximation for the true climate.
From the above, it is clear that climate plays an important role in the design of a building.
Stuart Gadsden, Environmental Engineering, University of Strathclyde, 1997.

The outdoor climate parameters that would be of particular interest are:

  1. Solar radiation levels (direct & diffuse): This information would be required to assess the performance of any passive or active solar systems incorporated into the building.
  2. Cloud cover: This would be helpful in predicting the amount of solar radiation reaching the building facade or solar collectors.
  3. Sunshine hours: Again helpful in assessing solar system performance & design.
  4. Predominant wind direction & speeds: Useful in the design & performance assessment of any natural ventilation systems.
  5. Wet & dry bulb temperatures: Used to calculate Relative Humidity. This information would be useful in the design & assessment of any air conditioning or dehumidifying systems.
  6. Rain levels: Could be useful when considering the viability of a self filling solar pond for the purpose of building cooling.

---In terms of the lack of climate data:
Perhaps climate data from another known source within a similar environment could be used to predict building performance.
or
It may be possible to use the Climate Severity Index(CSI, Markus et al 1984) to give some comparitive measure of the performance of that building type.
or
Use of the Solar Radiation Prediction method could be used to assess any solar systems installed together with educated estimates of the other parameters.
I would expect that a mixture of all these suggestions would have to be used to give some kind of realistic impression of building performance.
David Forbes, Environmental Engineering, University of Strathclyde, 1997.