Other Cooling Technologies
This section includes absorption cooling, radiant cooling, and earth cooling tubes.
Absorption Cooling
Absorption cooling is essentially an air conditioner driven not by electricity, but by a heat source such as natural gas, propane, solar-heated water, or geothermal-heated water. Because natural gas is the most common heat source for absorption cooling, it is also referred to as gas-fired cooling. Although mainly used in industrial or commercial settings, absorption coolers are now commercially available for large residential homes.
Absorption cooling usually only makes sense in homes without an electricity source, but may also be employed to make use of renewable energy. Absorption cooling is essentially a heat pump technology; absorption coolers are absorption heat pumps that are not set up to allow their use as a heating device. To find out more about absorption cooling, see the section on absorption heat pumps.
Radiant Cooling 
Radiant cooling cools a floor or ceiling to provide a cooling effect by absorbing the heat radiated from the rest of the room. Although potentially suitable for homes in arid climates, radiant cooling is problematic for homes in more humid climates.
Earth Cooling Tubes
Earth cooling tubes involve routing air through underground tubes or chambers to achieve a cooling effect. Although a few hundred systems were build in the 1970s and 1980s, in practice the technology is not effective.