Micro-cogeneration Pour Les Batiments Residentiels Fonctionnant Avec Des Energies Renouvelables (micro Combined Heat and Power Operating on Renewable Energy for Residential Building)

A micro Rankine cycle system using wood and solar energies for combined production of electricity and thermal energy is studied. For low power output (< 10 kW), micro Rankine cycle design and its energy performances depend strongly on the properties of the working fluids. Organic fluids present many advantages compared to water for Rankine cycle utilizing low-grade energy as heat input, and particularly for low power output. In this study, the required characteristics of the “ideal” working fluid have been identified. Since such an ideal fluid that fulfills all requirements does not exist, a screening method has been developed to draw a list of the most suited working fluids for the specific application. The screening procedure developed is composed of four different selection phases. The first three phases depend mainly on environmental, safety, and performance criteria. However, the last phase of the screening process requires the evaluation of the thermodynamic and thermophysical properties effect of the working fluids on the design of the different Rankine cycle components.