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This work presents a combined experimental and thermodynamic approach used to investigate the influence of droplet injection on the performance of an ejector-based refrigeration cycle developed for Heating, Ventilation and Air-Conditioning (HVAC) applications. Thermodynamic models have been developed within MATLAB for each component of the cycle. They are validated against experimental data of an R245fa test rig installed at Hydro-Quebec's Energy Technologies Laboratory (LTE). The numerical models agree fairly well with the experiments. The results show that injecting R245fa droplets at the end of the ejector diffuser with different glycol temperatures ranging from 20 to 26 °C has a significant impact on the performance of the ejector itself and more interestingly on the performance of the whole cycle. It reduces especially and significantly the temperature and the pressure of the overheated vapors at the outlet of the ejector leading to a significant improvement of the thermodynamic coefficient of performance (COP) by up to 20%.

Adrar is a city in the Sahara desert, in southern Algeria known for its hot and dry climate, where a huge amount of energy is used for air conditioning. The aim of this research is to simulate a single effect lithium bromide–water absorption chiller coupled to a double-glazed flat plate collector to supply the cooling loads for a house of 200m2 in Adrar. The thermal energy is stored in an insulated thermal storage tank. The system was designed to cover a cooling load of 10.39KW for design day of July. Thermodynamic model was established to simulate the absorption cycle. The results have shown that the collector mass flow rate has a negligible effect on the minimum required collector area, but it has a significant effect on the optimum capacity of the storage tank. The minimum required collector area was about 65.3 m2, which could supply the cooling loads for the sunshine hours of the design day for July. The operation of the system has also been considered after sunset by saving solar energy.

In this work a statistical analysis of wind speed is carried out, using meteorological data, in order to estimate wind characteristics in different regions of Algeria and accordingly determine the most efficient sites.The probability density curve of wind speed can provide useful information about the wind variation such as average and mean speed; it can also be helpful for the estimation of extreme wind occurrence. All these gathered pieces of information can be used efficiently to make a good decision about the wind site selection and to achieve an optimal design of a wind turbine, being energetically efficient and structurally sound. The wind statistical distribution, for a given site, can be also useful in fatigue calculation since it can determine the number of cycles completed, at different wind speed ranges, during the lifetime of the turbine.In the second part of this work, dynamic stresses are computed for the root region of the blades, using finite element modelling. This region is a highly load...