Travail de fin d'études et stage[BR]- Travail de fin d'études : Modelling of desiccant evaporative cooling system[BR]- Stage d'insertion professionnelle (ULiège)

Abstract

In a context of climate changes around the world and a willingness to achieve the goal fixed, the 2015 Paris Agreement, decarbonized strategies must be established. With this climate change, an increase in cooling consumption of buildings can be expected. The current solution to achieve thermal com- fort in buildings is to install air conditioning units to produce fresh air to cool the buildings. These conventional air-conditioning systems consume a relatively large amount of electricity to produce this cold, but also use refrigerants that contribute to the greenhouse effect and the destruction of the ozone layer. However, there are alternatives to conventional air conditioning, including evaporative cooling systems with a desiccant wheel. The aim of this study is to evaluate different evaporative cooling techniques, including a review of the different possible designs and configurations. A modelling of the whole cycle for a standard configuration is performed. The modelling of each component of the cycle is addressed, a simple model for each component and a complex model for the desiccant wheel and the rotary air-air exchanger. A parametric study for each model is carried out in order to observe the impact of the evolution of the parameters on the outputs of each model. A calibration of the simple models for the desiccant wheel and the rotary air-air exchanger is carried out from data generated with the complex model as well as a validation in order to evaluate the relevance of a simple model next to a complex model. For the desiccant wheel, the simple model can substitute the complex model because the error on the desiccant wheel output is ±0.5[K] and ±0.3[g_water/kg_air]. For the rotary exchanger, the simple model does not allow to substitute the complex model, other elements like the flow rate must be taken into account in the efficiency calculation. This type of technology can be applied especially in hot and humid climates as it allows the regulation of both temperature and humidity to ensure optimal thermal comfort. Even more so by improving the way in which the regeneration temperature of the desiccant wheel is reached as well as by installing solar collectors in order to make the system almost autonomous in energy.