## 3 Results
### Temperature-Humidity Index  
Figure 6 shows the behaviour of the Temperature-Humidity Index computed for the outlet pad thermal conditions. THI computed for the external thermal conditions was also shown for comparison purposes (green dash-doted line). THI at pads outlet was below the THI at pad inlet, thus all the pads improved the thermal comfort conditions of the air at outlet. As a reference, the zone of the middle thermal stress defined for cattle is shown with black dash-dot lines (\(72\leq THI\leq 78\)) [55]. For the inlet thermal conditions analysed (\(T_{di_{i}}=30\)\({}^{\circ}\)C and \(\phi_{i}=60\%\)), Figure 6a,b shows that the THI of the \(CL\) pad was furthest away, around 5.5 units below the external THI, followed by the \(CS\) pads (around 4.1 units below). The \(PS\) pads were closer to the external THI (around 2.6 units below). The inlet air velocity and pad thickness changes have little effect over THI. Figure 6a shows that the THI behaviour of the \(CL\) pad varied inversely to the alternative pads, which decrease THI when increasing the inlet air velocity. It is not possible to generalize the behaviour due to the pad thickness influence, because for the \(CS_{1}\) and \(PS_{2}\) pads it was opposite to the \(CL\) pad's behaviour, as is shown in Figure 6b. Due to the way THI was computed, the dry-bulb temperature and relative humidity of inlet air have a strong influence over it. When \(T_{di_{i}}\) changed, the THI upper limit of the middle comfort zone (THI = 78) in Figure 6c was reached before by the \(PS_{2}\) pad at 30.7 \({}^{\circ}\)C and 1.7 \({}^{\circ}\)C above it by the \(CL\) pad. THI increased linearly with \(T_{di_{i}}\) with the same slope for all the pads (\(\approx\)1.4 THI units per \(T_{di_{i}}\) unit). A similar behaviour occurs when \(\phi_{i}\) changed. THI was less susceptible to \(\phi_{i}\) changes than to \(T_{di_{i}}\) ones (\(\approx\)0.3 THI units per \(\phi_{i}\) unit for the \(CL\) pad). The upper limit of the middle thermal comfort zone (THI = 78) is reached before by the \(PS_{2}\) pad when \(\phi_{i}\) was 54.8% and later by the \(CL\) pad when \(\phi_{i}\) was 63.9%.  
Non statistically significant evidence was found (0.3246 \(\leq p\)-value \(\leq\) 0.7427) to consider that there are differences between the medians of all the pads for the THI and dry-bulb temperature of the inlet air relationship, between the medians of all the pads (except between \(CL\) and \(PS\) pads) for the THI and relative humidity of the inlet air relationship (0.1020 \(\leq p\)-value \(\leq\) 0.8014).  
Figure 5: Comparison of pad cooling efficiency (\(\eta\)) of each pad analysed. (**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 (\(T_{di_{i}}\)). (**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, \(T_{di_{i}}\) = 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.