The energy requirements and demands of air conditioning systems is steadily increasing. The use of solar assisted Single Effect Absorption Chillers (SEAC) can alleviate energy losses and reduce CO2 emissions. The needs to customize such systems is crucial. Hence, the feasibleness of using a absorption solar cycle in Najaf, Iraq is evaluated in this study. In the system proposed, a 105,6kW SEAC is powered by Evacuated Tube Collectors (ETC). TRNSYS (version 18) simulation is performed to select the various system parameters and optimize them to increase solar system efficiency, and this simulation develops a solar cooling model that simulates reality and is used effectively for cooling service buildings. According to the results, the optimum solar air-conditioner for a building consists of a 35 m2 collector area with 8 collectors connected in series and at a tilt angle of 32 degrees for Najaf, Iraq, from the horizontal and 1.5 m3 HWST. Moreover, it has been found that in effect, the solar absorption cycle reduces the annual electricity consumption where the solar fraction is high, reaching 77% at Najaf, Iraq. Also Utilizing solar energy can provide further benefits to the governments in the form of CO2 reduction, as the thermal energy generated by solar evacuated tube can reduce the energy used when the greatest percentage of CO2 reduction moreover 70.33 tons of CO2 for Tehran and 68.88 tons of CO2 in work period in each year.