## 1 Introduction  
There is growing demand for air conditioning in hot climate countries (due to increase in internal loads in buildings), and greater demand for thermal comfort by its users; thus, it is becoming one of the most important types of energy consumption [1]. Accordingly, the consumption of electrical power by refrigeration equipment begins to cause problems in the supply network on the hottest summer days. Most buildings are provided with electrically driven vapor compression chillers. Currently, the energy for air conditioning is expected to increase tenfold by 2050 [2]. In Iraq, the demand for cooling and air conditioning is more than 50%-60% of total electricity demand (48% in the residential sector) [3]; thus, it contributes to increased CO2 emissions, which could increase by 60% by 2030, compared to the beginning of the century (even though we urgently need to reduce) [4]. On the other hand, mechanical compression chillers utilize various types of halogenated organic refrigerants, such as HCFCs (hydrochlorofluorocarbons), which still contribute to the depletion of the ozone layer; this is why many of these refrigerants have been banned or are in the process of being banned. To enhance a building's energy efficiency, solar-driven cooling systems seem to be an attractive alternative to conventional electrical driven compression units, as they achieve primary energy savings and reduce greenhouse gas emissions for solar fractions higher than about 50% [5]. They use refrigerants that do not harm the ozone layer and demand little external electric power supply. The simulations of lithium bromide (LiBr)/water (H2O) absorption cooling systems have a long history, but a general model for all circumstances is still elusive. [PERSON] et al. [6] presented a simulation of a LiBr-H\({}_{2}\)O absorption chiller of 10 kW capacity for a small area of 100 m\({}^{2}\) under three different zones in Australia. They concluded that the best system configuration consists of a 50 m\({}^{2}\) flat plate collector and a hot water storage tank of 1.8 m\({}^{3}\). In Tunisia, a feasibility and sensitivity analysis of the solar absorption cooling system was conducted by [PERSON] et al. [7] using TRNSYS (University of Wisconsin-Madison, Madison, WI, USA, 1994) and EES software. They concluded that a house of 150 m\({}^{2}\) required 11 kW of absorption chiller, with 30 m\({}^{2}\) of flat plate solar collectors and a 0.8 m\({}^{3}\) storage tank to cover the cooling load. For their part, [PERSON] et al. [8] compared the simulation of a solar cooling system using TRNSYS software, with real data from a system installed in Alicante, Spain. The air-conditioning system was composed of a LiBr-H\({}_{2}\)O absorption chiller with 17.6 kW capacity and 1 m\({}^{3}\) hot storage tank. The results show an approximation between the measured and simulated data, where the coefficient of performance (COP) of the absorption chiller from the experimental data was 0.691 while the COP of the simulated system reached a value of 0.73. [PERSON] [9] described a 250 m\({}^{2}\) field of vacuum tube solar thermal collectors, which provided hot water at temperatures of about 90 \({}^{\circ}\)C, to drive lithium bromide/water absorption chiller with a capacity of 95 kW, utilized to cover the thermal loads for a building of 4000 m\({}^{2}\), which included offices, laboratories, and a public area. [PERSON] et al. [10] evaluated the performance of a LiBr-H\({}_{2}\)O absorption chiller with 35 kW cooling capacity, integrated with 72 m\({}^{2}\) of evacuated tube collectors (ETC) and an auxiliary boiler. They found that the solar absorption system had high performance with a ratio of 2.63 m\({}^{2}\) of collector area for each kW of air-conditioning. A solar parabolic trough collector has been used beside a single effect LiBr-H\({}_{2}\)O absorption chiller [11]. [PERSON] [12] studied the principles of the operation of the solar absorption cooling system. The total solar area was 1450 m\({}^{2}\).