This master thesis aims to develop a methodology to identify the optimal operation of different HVAC system configurations for different climate conditions and building typologies. To reach the objective, the work is carried out in three main steps using dedicated tools (DesignBuilder, EnergyPlus, and eppy script (python language)) and running co-simulation. In addition, the nZEB standard established by the most recent edition of the Spanish Technical Building Code is addressed in this study through a parametric optimization study of a reference building. The effectiveness of this legislation is evaluated in terms of its capacity to disseminate the idea of building energy cost optimization and reduce the annual energy consumption in the residential sector. To this end, a reference building was designed and multiple HVAC designs were evaluated using DesignBuilder building energy simulation software and found the best optimization of HVAC solutions through EnergyPlus and eppy. In total, a set of 30 alternative scenarios was established and parametrically evaluated for 5 cities representing the 5 climatic zones of inland Spain (Bilbao, Burgos, Seville, Madrid, and Almeria) resulting in 150 simulations. The results were evaluated utilizing annual energy consumption (electricity, natural gas, and other fuels) values concerning the calibration of set point manager temperature (heating), obtaining the cost-optimal and minimum consumption levels of annual energy. It is worth mentioning that this study is mainly concentrating on the Energy Supply System (ESS), where the Energy Saving Measure (ESM) is kept unchanged, which should be reviewed in future updates
