It is possible to model freezer zones in DesignBuilder, but it is important to ensure that the temperature of the supply air is set to a very low value to cool the air below zero.
If you are using Simple HVAC then take these steps:
- Reduce the cooling supply air temperature in the Cooling design calculation options to -99°C.
- Reduce the supply air temperature under Cooling on the HVAC tab in the freezer zones to -99°C.
- Switch off heating on the HVAC tab.
- Switch off Mechanical ventilation on the HVAC tab.
- On the activity tab, set the cooling setpoint and setback temperatures to the required freezer zone air temperature.
- Set the cooling operation schedule to 'On' so that it always operates.
When using Compact HVAC apply these additional steps (this is a legacy option not available in v5 or later versions):
- Use the "Packaged direct expansion" template for the freezer zones (load this before applying the above changes).
Following these steps allow you to cool zones down to very low temperatures.