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Quadrotor Unmanned Arial Vehicles (UAVs) are commonly used for complex tasks such as, surveillance, search and rescue in hazard locations for its small size, lightness and robustness. However, the stability of UAVs represents a big challenge due to its high Nonlinear, multivariable, strongly coupled nature. The present work investigates two commonly-used control strategies namely, PD-control with low pass filter and Nonlinear feedback linearization control. The parameters of each controller are optimized to set the time-domain performance within specific constrains. The performances of the two control strategies are simulated and the results are validated on real experiments. The results indicate that Nonlinear control can substantially expand the region of controllable flight angles compared to linear control. It can stabilize the quadrotor system in case of multi angle disturbances. PD-controller with low passes filter shows poor performance when it synchronously controls more than one angle at the same time.

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The objective of the present work is to assess experimentally the performance characteristics of a R410A domestic air conditioner under different in-door operating conditions. In order to achieve this objective, a test facility of the investigated system is developed and experiments are conducted. Experimental results on R410A air conditioning system are obtained over a wide range of in-door operating conditions. Experimental results confirmed that the cooling capacity, compressor power and COP increase by 90.9%, 5.2% and 81.5%, respectively, as air humidity ratio increases from 8 to 25.5[Formula: see text]gw kg[Formula: see text]. The cooling capacity, condenser heat load, compressor power and COP increase by 7.2%, 6.1%, 2.8% and 4.1%, respectively, when the evaporator air inlet temperature increases from 28[Formula: see text]C to 34[Formula: see text]C for a given humidity ratio. COP increases by 25.6% while pressure ratio decreases by 2.5% as the air volume flow rate increases from 400 to 550[Formula: see text]m3 h[Formula: see text].

Climatic change illustrates the need to new policy of load management. In this research, a special design of thermal energy storage (TES) system, with an appropriate storage medium that is suitable for residential and commercial buildings has been constructed and commissioned. Direct contact heat transfer is a significant factor to enhance the performance of TES. Numerous experimental runs were conducted to investigate the clathrate formation and the characteristics of the proposed TES cooling system; in addition, the effect of using nanofluid particles Al2O3 on the formation of clathrate under different operating parameters was evaluated. The experiments were conducted with a fixed amount of water 15 kg, mass of refrigerant to form clathrate of 6.5 kg, nanofluid particles concentration ranged from 0.5% to 2% and the mass flux of refrigerant varied from 150 to 300 kg/m2 s. The results indicate that there is a significant effect of using nanoparticles concentration on the charging time of the clathrate formation. The percentage of reduction in charging time of about 22% was achieved for high nanoparticles concentration. In addition, an enhancement in charging time by increasing the refrigerant flow rate reaches 38% when the mass flux varied from 200 to 400 kg/m2 s. New correlation describing the behavior of the temperatures with the charging time at different nanoparticles concentrations is presented.