## 3 Results
### Relative Humidity Increase  
Contrary to the results presented before, the increase of the relative humidity at the outlet of the pads (\(\Delta\phi\)) for the \(CL\) pad was located between the alternative pad's results, as is shown in Figure 8. The lowest \(\Delta\phi\) was for the \(PS\) pads, followed by the \(CL\) pad, while the \(CS_{2}\) had the highest. \(\Delta\phi\) of the \(CS_{1}\) pad increased when the inlet air velocity increasing; opposite to the behaviour of the other alternative pads (Figure 8a). The \(CL\) pad presented the highest change of \(\Delta\phi\) (3.8%) due to inlet air velocity. The influence of the pad thickness over \(\Delta\phi\) is stronger, changing up to 10.0% for the \(CL\) pad (Figure 8b). \(\Delta\phi\) increases when increasing the pad thickness, for all the pads. Increasing the dry-bulb temperature of inlet air had a non-significant effect on \(\Delta\phi\), with a maximum change of 1.2% for the \(PS_{2}\) pad (Figure 8c). In this case, the behaviour of the \(CL\) pad was opposite to  
Figure 6: Comparison of the air outlet Temperature–Humidity Index (THI) of each pad material analysed. (**a**) As function of inlet air velocity (\(u\)). (**b**) As a function of pad thickness (\(L\)). (**c**) As a function of dry-bulb temperature of inlet air (\(T_{db_{i}}\)). (**d**) As a function of relative humidity of inlet air (\(\phi_{i}\)). For each plot, the other parameters remained constant: \(u\) = 1.5 m s\({}^{-1}\), \(L\) = 0.1 m, \(T_{db_{i}}\) = 30 \({}^{\circ}\)C and \(\phi_{i}\) = 60%. \(CL\): solid black line; \(CS_{1}\): blue solid line; \(CS_{2}\): blue dashed line; \(BC\): red solid line; \(PS_{1}\): magenta solid line; \(PS_{2}\): magenta dashed line; inlet air THI: green dash-dot line; middle thermal comfort THI zone for cattle: black dash-dot line. the alternative pads, indicating that the \(CL\) pad increase the evaporation rate when \(T_{dh_{z}}\) increased. \(\Delta\phi\) across the pads was more susceptible to the changes in the relative humidity of inlet air. Figure 8d shows that all the pads present the same behaviour, decreasing \(\Delta\phi\) when increasing \(\phi_{i}\). The changes of \(\Delta\phi\) were between 22.3% and 13.4% for the \(CS_{2}\) and \(PS_{1}\) pads, respectively. Those values correspond to a decrease of 0.6% and 0.3% per unit increment of \(\phi_{i}\), respectively. When \(\phi_{i}\) increased, decrease the ability of the air to hold the water vapour and consequently evaporate a less amount of water from the pads. Non statistically significant evidence was found to consider that there are differences between the medians of \(CL\) and \(BC\) pads for the relative humidity increment and inlet air velocity relationship (\(p\)-value = 0.2934); between the medians of the paired pads \(CL-CS_{1}\), \(CL-BC\), \(CS_{1}-CS_{2}\) and \(PS_{1}-PS_{2}\) for the relative humidity increment and the pad thickness relationship (0.2934 \(\leq p\)-value \(\leq\) 0.6936); and between the medians of the pads \(CL-CS_{1}\), \(CL-BC\), \(CS_{1}-CS_{2}\), \(CS_{1}-BC\) and \(PS_{1}-PS_{2}\) for the relative humidity increment and the relative humidity of inlet air relationship (0.2085 \(\leq p\)-value \(\leq\) 0.8999). Figure 8: Comparison of inlet-outlet relative air humidity change (\(\Delta\phi\) [%]) of each pad material analysed as a function of operative and geometric parameters. (**a**) As function of inlet air velocity (\(u\)). (**b**) As function of pad thickness (\(L\)). (**c**) As function of dry-bulb temperature of inlet air (\(T_{dh_{z}}\)). (**d**) As function of relative humidity of inlet air (\(\phi_{i}\)). For each plot the other parameters remained constants: \(u\) = 1.5 m s\({}^{-1}\), \(L\) = 0.1 m, \(T_{dh_{z}}\) = 30 \({}^{\circ}\)C and \(\phi_{i}\) = 60%. \(CL\): solid black line; \(CS_{1}\): blue solid line; \(CS_{2}\): blue dashed line; \(BC\): red solid line; \(PS_{1}\): magenta solid line; \(PS_{2}\): magenta dashed line. Figure 7: Comparison of inlet-outlet air dry-bulb temperature change (\(\Delta T\)) of each pad material analysed.