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Vapor compression cooling systems are widely used in hot and dry climates where the atmospheric temperature in summer reaches around 48 °C and the relative humidity can be below 20%. These cooling systems normally use environmentally friendly gases that do not harm the ozone layer. These systems work with high gas pressure, which consumes high energy and leads to a low coefficient of performance when compared to cooling systems that do not use an environmentally friendly gas. Theoretical and experimental studies have been conducted to find a suitable solution for the performance improvement of this type of cooling system. A possible solution is to lower the temperature of the air before it enters the condenser of the compression cooling system by passing it through a wet pad. The water evaporates due to the latent heat that is withdrawn from the wet pad. The air temperature is reduced to about 11 °C before it enters the condenser of the compression cooling system. This enhancement increases the cooling capacity of the vapor compression cycle by nearly 20% and increases the coefficient of performance by 15%, in addition to reducing the consumed electricity up to 15%. In conclusion, the proposed method of adding a wet pad can significantly enhance the performance of the vapor compression cooling system.

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A Suspension system can be defined as the mechanism that physically separates the car body from the car wheels. The purpose of any suspension system is to increase the ride comfort, road handling and stability of closed loop system. The suspension design must be compensate the effect of conflicting criteria of road holding, load carrying and passenger comfort. An active suspension system has been proposed. A quarter-car two degree-of-freedom (2DOF) system is designed and constructed to simulate the actions of an active quarter car suspension system. White noise input is introduced to a given system to expressed unpaved road and both step input and sine wave input are studied as well. The control strategy is based on two degree of freedom PID controller. (MATLAB/ Simulink) is used to verify the proposed algorithm. The comparison between the passive and active suspension and the results obtained from a range of road input simulations in the proposed algorithm shows the effectiveness of the proposed algorithm and best results are obtained.