The above example is taken from a recent design with a very modest roof height. With displacement, as the height of extraction increases so does the temperature gradient, resulting in reduced air volumes and increased energy savings.
For example, if the roof height was 7m instead of 5.5m, the energy saving would be ~£13,200 pa. The “control point” i.e the height at which the design temperature is required, is not affected by the extract height. |