**5. Conclusions**

This article presented a detailed analysis of the performance of a solar driven-absorption cooling system as alternative technology for air conditioning of a house, under hot and dry climate in Baghdad, Iraq. Various parameters influencing the solar fraction and the solar cooling performance of the proposed system have been discussed.

Based on the results of the simulation performed in this work, it was revealed that weather conditions have a significant effect on the performance of the solar absorption air conditioning system, with peak loads during the summer months. August presented the highest performance. The relevant average COP achieved a value of 0.52 while the solar fraction was 59.4%.

The results (of energy analysis contribution) during the summer season showed that the amount of energy incident was 178,023 kWh, while the total energy harvested was 96,073 kWh, which implies

that the efficiency of ETC collectors during the cooling season is about 54%. It was also found that the solar energy supplied by the solar tank was 34,730 kWh and the energy delivered by the boiler was 26,025 kWh, indicating that the total seasonal solar coverage was about 58%.

The results of the primary energy analysis evidenced the use of a collector area of 35 m2; a storage tank volume of 2000 L presented better performance than that reached in the base case.

Parametric analysis results showed the best configuration for the design of SACS. It was found that the solar collector tilt angle is significantly affected by the incident solar irradiation. An optimal value (between 15◦ and 25◦) of the inclination presented a higher solar fraction. It was also found that increasing the water flow rate through the collectors does not indicate a significant effect on solar coverage.

The surface collector analysis revealed that, in general, the increase of the installed surface of the collector field leads to improve the solar fraction values. It was also found that the solar fraction remained the same for an area larger than 55 m2. Therefore, it is concluded that the appropriate collector surface selection should be carried out together with economic and technical feasibility (mainly cost analysis and land availability) in order to achieve the best profitability of the system.

Moreover, the change in the size of the solar tank has no significant impact on the solar fraction (60.6% and 61.1% for 10 <sup>L</sup>/m<sup>2</sup> and 55 <sup>L</sup>/m<sup>2</sup> of collector area, respectively). Increasing the upper solar tank temperature improves the solar coverage, but it should be <95 ◦C.

Finally, this work provides a roadmap for designers, in particular, to ensure that all of the operating and design variable effects are taken into consideration when developing a solar air-conditioning cycle under the Iraq climate. Additionally, the model can be employed to carry out thermo-economic comparisons of the system using various types of collectors.

**Author Contributions:** Conceptualization, A.A.-F.; methodology, A.A.-F.; validation, A.A.-F.; formal analysis, A.A.-F.; investigation, A.A.-F.; data curation, A.A.-F.; writing—original draft preparation, A.A.-F.; writing—review and editing, F.A.; supervision, B.E. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors received no specific funding for this work. The corresponding author would like to thank the Technical University of Darmstadt, enabling the open-access publication of this paper.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Nomenclatures, Subscripts and Abbreviations**
