HVAC tab in model data
The Dynamic Gradient Air Distribution model data allows you to model stratification within a zone by setting up a temperature gradient which varies dynamically depending on:
Changing the Distribution mode to 2-Dynamic gradient reveals the air temperature distribution data. By default the Interpolation mode is 2-Inside-outside DeltaT. This means that the temperature gradient within the space is modelled as varying according to the inside-outside temperature difference. The Upper conditions define the most extreme temperature gradient, typically under design conditions. By default, the upper temperature difference is 10 °C and the corresponding temperature gradient is 4 °C/m. This means that when the temperature difference between inside and outside is 10 °C or more the internal temperature gradient is 4 °C/m. The Lower conditions data shows that when the temperature difference between inside and outside is zero there is no temperature gradient, i.e. the air is fully mixed. EnergyPlus calculates the temperature gradient for other inside-outside temperature differences by linear interpolation.
The operation schedule defines the times when air temperature distribution is to be calculated. When the value of the schedule is 1, the distribution calculations take place, when the value is 0, the zone air temperature is fully mixed.
Thermostat height specifies the distance above the floor where the thermostat for HVAC control is situated. This height is used by the model to determine the thermostat temperature relative to the mean air temperature by applying the gradient.
Return air height specifies the distance above the floor where the air leaves the zone and returns to the air system. This height is used by the model to determine the return air temperature relative to the mean air temperature by applying the gradient.
The air temperature distribution within the zone is used as follows:
The air temperature distribution mechanism does not include: