You can use the information attainted through visualizing the temperature field to determine how to modify parameters on the Forces tab of the Smoke Solver.
Visualizing hot fluid
Use the Source from volume tool on the Volume Fluids shelf tab to make the sphere emit smoke.
On the Smoke Object, turn on the Show Guide Geometry checkbox on the Temperature subtab of the Guides tab.
This will create a grid that changes color to provide valuable information about the temperature of the simulation. Blue indicates a cooler temperature and red indicates a hotter temperature. This is useful for simulating fire and explosions.
Visualizing cold fluid
You can also visualize cold fluid by changing a few parameters in the simulation.
On the Static Object, change the Temperature from 1 to -1.
On the Smoke Object, navigate to the Temperature subtab of the Guides tab and change the Guide Range parameter from 0 and 1 to -1 and 0.
Blue indicates a cooler temperature and red indicates a hotter temperature, as in the first example.