Setting Up a Mixed Mode System

To model a mixed mode system, you will need to have set up mixed mode aperture types in the source building.

These spaces will be cooled to 27 degrees C. The cut-off temperature should not be higher than 25 degrees C to ensure that the apertures will be fully closed at 26 degrees C.

The bypass factor determines the proportion of air that will pass through the cooling coil and therefore how much air will bypass it altogether. It is commonly used to express the efficiency of a cooling coil. If the contact factor is known then the bypass factor can be calculated using the following relationship: Bypass Factor = 1 - Contact Factor.

Monitoring for out-of-range values set to True will reduce the heating, cooling, auxiliary, and HWS consumption by 5%.

Exercise and Notes

  1. Set the bypass factor to 0.1.

  2. The terminal fan SFP has been specified as 0.3 W per l/s.

  3. The extract fan will be modelled with an SFP of 0.6 W per l/s.

  4. The fresh air fan will be producing 1.2 W per l/s.

  5. These zones will benefit from demand control ventilation as a function of occupancy density where air flow will be regulated by fan speed as opposed to dampers.

  6. Monitoring for out-of-range values = True.