## 4 Results  
In this section, the experimental data obtained for both: the parabolic trough collector field and the absorption cooling system are presented. As it was mentioned before, this investigation proposes the coupling between these independent systems. The coupling is proposed to be through a storage tank, where the thermal energy gained in the solar field becomes available to be supplied to the generator in the absorption cooling system. Using a storage tank involves one major advantage: (although there is temperature stratification in the storage tank,) after the transient heating process where the fluid average temperature is increasing, there is a process where the maximum fluid temperature is achieved and it remains almost constant for at least two hours (see see Figures 4, 6, 8 and 10). So, it is possible to supply the heating fluid at a constant temperature to the generator in the absorption cooling system. In order to simulate the conditions of the heating fluid that would be achieved with the solar system, for the results presented in this section, it was used the auxiliary heating system described in Section 2.2, which supplies the heating fluid to the generator at constant temperature. Several tests for different generation temperatures that are easily achieved with the solar system were performed with the absorption cooling system. Figure 4 shows the temperature profiles of the storage tank, inlet, and outlet temperature as a function of solar irradiance (\(G_{b}\)) corresponding to November 24. The test was considered for an office schedule from 10:00 a.m. to 16:00 p.m., the solar radiation showed a Gaussian profile, this day the maximum \(G_{b}\) was 856 W/m\({}^{2}\) in Cuernavaca city. In the storage tank profile, it is possible to identify three sections: the transitory section from 9:30 a.m. to 12:00 p.m., the stable section from 12:00 p.m. to 14:00 p.m., and the cooling section from 14:00 p.m. to 16:00 p.m. The temperature profiles increased as the solar irradiance increased, however, the \(G_{b}\) decreased after the 12:00 p.m. The behavior of the storage tank temperature profile was kept constant for two hours. The average temperature held in the storage tank was 97.2 \({}^{\circ}\)C, the maximum outlet temperature HTF was 103.3 \({}^{\circ}\)C.  
Figure 4: Behavior \(G_{b}\) and outlet, inlet, and storage tank temperatures, 24 November 2017. The thermal efficiency and the useful heat were calculated during the stable section, these behaviors were shown in Figure 5. This plot shows the behavior of several parameters every 10 min. The maximum value calculated for thermal efficiency was 19.8% and the minimum 9.8%. The useful heat was determined considering 38.43 m\({}^{2}\) as the total collector's area and \(G_{b}\) in a range from 759 to 854 W/m\({}^{2}\). The results show the useful heat can reach 6.5 kW as maximum and 3 kW as a minimum. The behavior of Qu is not constant due to the \(G_{b}\) variation during the test. The exergy efficiency follows the same trend than others parameters varying from 7 to 14.2%. The test of corresponding of 29 November is presented in Figure 6. It shows the profiles of inlet, outlet, and storage tank temperatures during the day in Cuernavaca city. The solar radiation showed a Gaussian profile, the maximum \(G_{b}\) was 835 W/m\({}^{2}\), after the 12:10 p.m. a few clouds showed up. The temperature profiles for the variables Tin and Tout, diminished when the clouds appeared. The evaluation was realized for 6 h (9:30 a.m.-15:30 p.m.). In this plot is possible to identify three sections also, the stable section was in a range from 11:39 a.m. to 14:39 p.m. During this section, the average storage tank temperature was 96.93 \({}^{\circ}\)C and the maximum outlet temperature of HTF was 102.72 \({}^{\circ}\)C.  
Figure 5: Thermal efficiency, exergy efficiency, and useful heat behavior, 24 November 2017. Figure 6: Behavior \(G_{b}\) and outlet, inlet and storage tank temperatures, 29 November 2017.