Fluid transfer of Energy
Convection: thermal convection occurs when a gas or liquid carries heat energy as it moves from one place to another.
The cause of fluid / gas flow can be natural or forced.
An example of this is the influx of warm air that flows into a refrigerated truck when the doors are opened on a hot summer day. The ambient heat energy is pulled into the energy void inside the cold truck.
Prevention: to prevent convection the flow of liquid / gas must be stopped. In our refrigerated truck scenario, it is not feasible to fully prevent an influx of warm air when the doors are opened. However, a refrigerator curtain behind the doors and thermal covers to protect the individual contents of the refrigerated truck will slow the convection rate significantly.