HVAC energy auditing of three university buildings

This thesis study applies the methods and tools of Commissioning to three buildings of Politecnico di Milano. Specifically Retro-Commissioning has been applied on the three Buildings with the aim of assess the buildings energy performance. Implementing a Re-Commissioning process means to assess building performance finding out faults in the HVAC systems, carrying out diagnosis and suggesting design improvements. To achieve such results dynamical modelling is widely used with the final target to improve comfort and attain energy savings. The first part of the study is focused on the acquisition of information via documents, inspections/walk-through and measurements. The acquisition of energy related measurements has been possible thanks to the sensors installed in the buildings and the nearest weather station. Data have been processed with SW tools producing graphs, diagrams and highlighting, inconsistent or missing values. The documents on the building and HVAC technology and the inspections have been used to understand the system and thus to identify malfunctioning. The second part of the study consists in identifying, through linear regression, the most reliable benchmark of building energy performance among multiple years data, i.e. to identify the best data set. The third part consists in creating detailed dynamic models, based on the description of the buildings as they are, through which building up base lines. This consists in calibrating the models to reproduce as much as possible the monitored data other than fitting the identified benchmarks. This part is mainly a detailed energy audit. An additional approach, based on Italian Standard, was also carried out and the results have compared with the benchmark, showing inconsistent results. This is practically a so called standard energy audit and its results demonstrate how this simplified approach is not suitable for analysing such building typologies.