# Potential Study of Solar Thermal Cooling in Sub-Mediterranean Climate
## 5 Conclusions  
Using solar power for the cooling and heating of buildings is a milestone in the search for environment-friendly technologies in the energy sector. Four solar absorption cooling systems with a nominal cooling capacity of 530 kW were installed in four sites in Jordan. The focus of the research was on the pilot system at the German Jordanian University campus. The system has a capacity of 160 kW for cooling and a 50 kW for heating. With the installed systems, Jordan is the first developing country to use solar thermal energy to cool buildings. The aim of these systems was not only to reduce cooling power consumption, but also to serve as a reference for researchers and experts in absorption chillers, as it is the first of its kind to be implemented in Jordan, the region, and among developing countries. An economic feasibility study was carried out for the absorption system taking the environment effect of the reduction of CO\({}_{2}\) emissions into account. This study was based on an evaluation of the solar thermal cooling system within four months of operation between May and July 2015.  
The system was economically evaluated based on the observed cooling capacity results with a COP of 0.32, and compared with the claimed COP of 0.79 regardless of the operating conditions. Several techniques were implemented to evaluate the overall economic viability in-depth such as present worth value, internal rate of return, payback period, and levelized cost of electricity. The aforementioned economic studies showed that the absorption cooling system is deemed as not feasible for the observed COP of 0.32 over a lifespan of 25 years. The net present value was equal to \(-\)137,684 JD and there was a payback period of 44 years, which exceeds the expected lifespan of the project. Even for an optimal operation of COP = 0.79, the discounted payback period was equal to 23 years and the LCOE was equal to 0.65 JD/kWh.  
The survey shows that there are several weaknesses for applying solar thermal cooling in developing countries, such as the high cost of these systems and, more significantly, the lack of experience for such systems. The solar thermal cooling systems currently installed in Jordan were either planned, built, and monitored by companies that specialize in solar thermal cooling, or were scientifically supported by a research institution and they were being evaluated via monitoring at the beginning of their operation.  
From this perspective, the solar thermal cooling systems currently installed are not the technologically-possible optimum. There is significant potential for reducing costs and/or increasing performance through technological improvements mainly at the system level for overall system optimization. The introduction of a more advanced control through the absorption chiller components will increase operational efficiency, improve the cooling capacity, and contribute to the reduction of CO\({}_{2}\) emissions. The main component in solar thermal cooling systems is the chiller and the most relevant controlled parameter is the hot water inlet temperature and mass flow. Optimization between high water temperature to the generator should be achieved, to increase the cooling capacity of the absorber, while preventing possible pump damage in the case of crystallization. The improvement of this advanced technology requires higher level of process control and professional expertise.  
Conceptualization, M.J.; methodology, M.J. and M.A.-A.; formal analysis, M.J. and A.A.; investigation, M.J. and A.A.; resources, N.B. and M.A.-A.; data curation, M.A.-A. and A.A.; writing--original draft preparation, M.J. and N.B.; writing--review and editing, M.J., M.A.-A. and Z.D.; supervision, M.J. and N.B. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The authors declare no conflict of interest.