## 5 Results and Discussion  
In this study, the control of the desiccant wheel and pre-cooled dew-point evaporation-cooling-system-based cooler is investigated for achieving high cooling performance with less energy consumption. The temperature and relative humidity of the room are controlled independently with a proportional-based new control strategy. With this new control strategy, the comfort of the room is adjusted quickly and robustly by managing the speed of the actuators in the cooler according to the operating conditions. By using variable speed actuators, the cooling performance of the cooler is improved and the energy efficiency increases with the adding extra operation modes to the control strategy. It was mentioned that the developed control strategy leads to a more energy efficient performance than the classical ON/OFF controller and classical proportional control with these adding modes such as automatic Stop/Run and different speed modes for each actuator. In this section, the control performance evaluations of the developed controller software were performed and the performance of reaching the set values and the energy-saving performance were analyzed. In the considered case, the temperature and relative humidity of the atmospheric air are equal to 32 \({}^{\circ}\)C and 60%, respectively. However, the initial temperature and relative humidity are assumed to be lower than that of the atmosphere. They are equal to 28 \({}^{\circ}\)C and  
Figure 2: (**a**) Basic scheme of the proposed feedback control system. (**b**) Developed control strategy. 50% and the heat and mass transfers from the outside to the inside lead to an increase in the temperature and relative humidity at the inside of the room and cooler. The temperature and relative humidity set values of the room were changed by the user during the operation. Set values were changed at 800 s for both room parameters. In the 800 th second, the temperature set value was reduced from 24 \({}^{\circ}\)C to 21 \({}^{\circ}\)C and the relative humidity set value was reduced from 43% to 35%. The control performances of the cooler and the produced control inputs for fans and DW are given in Figure 3. As can be seen from the figure, the START instruction was given to the cooler, which was still closed, at 75 s. After that, the water pump starts its operation in the normal operating mode (Mode-2). Then, the fans and desiccant wheel started to operate in the low-speed mode (Mode-2) after the 150 th second. Since the atmospheric air is fed into the room without being fully conditioned in this period, it causes an increase in the room temperature and relative humidity. After the 150 th second, the cooler switches to active control mode, and the cooler air is conditioned in line with the determined set values. The first set value for the temperature, 24 \({}^{\circ}\)C, was reached in approximately 650 s. If there is no change in the set value after this value is reached, the process will continue until the ON/OFF mode is active. Figure 3: _Cont._  
It is seen from Figure 3c that there is a similar situation for the relative humidity value and the first set value of 43% relative humidity is reached before the 500 th second. The state of reaching these set values continued until the change in the set values occurred at the 800 th second, and after the new set value was adjusted, the process of reaching new values for both temperature and relative humidity began. The new set values (21 \({}^{\circ}\)C and 35% RH) were reached at 1300 s for temperature and at 1100 s for relative humidity. The results show that the developed controller has a successful performance in bringing the room to comfort quickly and it has a robust performance against the disturbance effect. It is also seen that the control performance after changing the set values is good, too. Then, after a certain time, the automatic Stop/Run mode is activated and the cooler is turned OFF for energy saving.