Simultaneously, the interest for new existing technologies which are eco-friendly with the environment
has been already investigated by different research groups. These technologies are particularly related to
the study of absorption systems in so called hybrid systems that are combinations of solar thermal energy
and fossil fuels. Lamp and Ziegler (1998) discussed in their peer review paper that in air-conditioning
business a strong correlation often exists between insolation and cooling requirements. Therefore, the
interest in solar cooling by sorption systems has prevailed for several decades. Also the authors indicated
that solar-assisted air conditioning could play will a vital role if an effort is made for a greater
technological development of advanced solar collectors and cooling systems. [3]. Figueredo et al. (2005)
carried out an energy analysis of a double stage lithium bromide/water absorption system which was able
to cover a thermal demand of 200kW at temperature of 170 °C, it could be operated as a single stage
system at around 90°C, utilizing a solar heating system comprised of 182 m2 of vacuum tubes and as a
double stage system with a water boiler operating at 160°C, demonstrating that they could have savings
of 100 MWh and 22 tons of CO2 emissions per year