This demonstration shows some of the unique system modeling capabilities of GOTHIC, including the ability to use subdivided and lumped parameter volumes in the same model. It also shows some of the mechanical equipment components that are available.

The model contains two rooms and a tank, which are interconnected as shown in the picture. The room on the left is subdivided in two dimensions, while the one on the right is modeled as a lumped parameter volume. The tank below the larger room is subdivided in the vertical direction only.

A fan located in one of the ducts that connects the two rooms circulates air between them. The air being drawn through the fan is heated before it enters the lumped parameter volume.

Water in the bottom of the subdivided volume is continually draining into the tank located below it. A pump starts when the water level reaches a predetermined set point, returning the water from the tank to the subdivided volume. The return piping contains a heat exchanger to cool the water and a spray nozzle to inject it into the room as small drops. After the tank has been drained, a low level trip shuts the pump off. The subdivided room also contains four heater components, located near the left wall at the midplane, which are continually heating the room atmosphere throughout the calculation.

The temperature is initially uniform throughout the model, but a buoyant plume quickly develops around the heater components. The average temperature for the lumped parameter volume increases more gradually as heat is added by the fan component. As the temperature in the lumped volume increases, the discharge into the subdivided volume changes from a momentum dominated jet to a buoyant plume. The pump periodically cycles on and off as indicated by the changing water level in the tank. When the pump is on the effect of the cold spray is evident from the changing temperature distribution and velocity vectors in the subdivided room.