Air-conditioning in hot and arid environments is an essential
requirement for support of daily human activities.
The Middle East and many other countries around the
globe have a long summer season with a daily average
temperature of 358C and maximum values in the upper
forties. In addition, long spels of humid weather occur
during the summer season with relatively lower temperatures,
in the mid thirties, and very high relative humidity,
with average values above 60% and maximum values close
to 90%. In many of these countries, the energy used to
condition and cool the indoor air ranges from 40 to 70%
of the total energy consumption of the country. On a global
scale, the most common method used to accomplish indoor
air conditioning is the mechanical vapour compression
(MVC) system.