The main part of the working activity has been carried out at the CETHIL laboratory, in Lyon.

The first part of the work consists in a deep study of the regulatory framework composed by Directives, Standards and guidelines at the European level, and regulations and labels at the French national level. Then the attention moved to computer tools, the use of which is able to help designers and researchers to deal with the new challenges. In particular, among the building simulation software, the use of TRNSYS -Transient System Simulation Tool- has been explored. With regard to the optimization theme, the genetic algorithms methodologies for optimization have been studied within the software GenOpt - Generic Optimization program. Then, possibilities for coupling of the software have been researched through a bibliographic study on previous works and experiences described in some scientific papers and through a personal research activity.

The second part of the thesis concentrates on a case-study. The so-called “Corbioli House” is a high-performance single-family house situated in the Rhone Alpes region of France. The house was built as an exhibition pavilion of nZEB and was monitored with several temperature sensors and a weather station. In teamwork with other French students, the building and its complex energy system (composed by a reversible air/air heat pump, a mechanical ventilation system and a geothermal pre-heating system) have been modelled using TRNSYS. Then theresults of the model, in terms of indoor temperatures and energy consumptions, have been compared to the real data obtained from the monitoring system, so that the model has been calibrated and validated.

The so-adjusted model was then used to carry out the main part of the work, concerning optimization. With regard to technical optimization, some elements of the building envelope have been chosen and set as parameters, such as the insulation thickness, the window type and dimension, the solar protection dimension, the inertial mass. Using GenOpt a parametric study has been performed, in order to evaluate the impact of variation of each parameter on heating, cooling and total energy needs of the house (without taking into account the energy system efficiency), starting from four different initial performance scenarios. The same parametric study has been done on two other building prototypes, similar to the first one except for the envelope. Finally the obtained results (concerning the massive internal insulated envelope, the massive external insulated envelope and the light wooden envelope) have been compared.

As a further step, a cost function based on French market prices has been created for each parameter of each envelope system. Besides the heat pump, three energy systems (a gas condensation boiler, a wood boiler and an all-electrical radiator system) have been created in TRNSYS, together with its cost function. Finally, the three envelope systems with related parameters have been combined with the four energy systems and, with the help of GenOpt optimization algorithm, twelve cost-optimal curves (based on the Global Cost Method) have been obtained and compared, evaluating strength and weaknesses of each building configuration.