## 5 Case Study: Cuza School Pilot School  
The school building is in Bucharestand has a height regime of Basement + Ground floor + 2 Floors. From the information received from the manager of the building, it appears that it was built in 1967, the project being one that was often replicated during that communist period. The building has a rectangular shape with sides of 18.80 m and 45.50 m, respectively, and a footprint of approximately 765 m\({}^{2}\). The level heights are as follows: 1.80 m for the technical basement (partially) and 3.40 m for the ground floor, the 1 st floor, and the 2 nd floor, while the constructed area is 2435 m\({}^{2}\). From a functional point of view, the building includes 17 classrooms, laboratories for chemistry, biology and informatics, chancellery, library, bathrooms, administrative spaces (director's office), a medical office, technical spaces, annees, and storages, and it is considered as a typical school for Romania. The structure of the outer envelope is made of solid brick walls (fired clay elements) with a thickness of 37.5 cm. Inside the building are structural brick walls 25 cm thick. The exterior PVC joinery and double glazing is partially degraded. The building has a gable roof with a wooden frame. The construction was designed according to the seismic design norm P13 from 1963. The building is heated by steel radiators, a panel type, mounted on the walls with the help of support brackets and protected with masks to prevent injury to children by touching hot surfaces. The radiators are connected to the cogeneration system of the city of Bucharest, operating with a thermal agent with parameters of 80/60 \({}^{\circ}\)C, in quantitative regulation according to the outside temperature. The distribution of the thermal agent for heating and hot water for consumption is performed through the technical basement of the building and through columns to the floors. The lighting of the classrooms is performed with lighting fixtures equipped with compact fluorescent lamps, depending on the purpose of the rooms. The building is not equipped with mechanical ventilation and air cooling systems; thus, we expected high indoor pollution. In the period 2010-2011, thermal rehabilitation works took place with the aim of increasing the energy performance of the educational unit, respectively reducing the energy consumption for space heating, under the conditions of ensuring and maintaining indoor thermal comfort. Figure 1 illustrates the exterior facade and a typical classroom from this school. The thermal rehabilitation works consisted of the following:  
* Thermal insulation of the external walls with fireproof expanded polystyrene of a 10 cm thickness. * Replacement of the pipes for the distribution of the thermal heating agent with polypropylene pipes, in the areas where failures have occurred. * Restoring the thermal insulation of the distribution pipes in the basement or replacing them entirely. All the sanitary groups were equipped with exhaust fans, and to avoid overpressure, transfer grids are installed in the doors; the exhaust air flow from each compartment of the sanitary group is 100-120 m\({}^{3}\)/h. The first ventilation system was installed in Room (1) and it is heat recovery ventilation equipment that is usually mounted in a false ceiling or in a space adjacent to the classroom, thus allowing the floor to remain free; the module is connected to the piping necessary for the supply of fresh air and the exhaust of stale air to the outside, but also to the network of ventilation ducts for the supply/exhaust of air from the classroom. It is also used in the free-cooling version when the outside temperature is lower than the inside temperature (for example, during the night). It can be used as an individual ventilation unit or can be integrated into air conditioning systems (air-refrigerant type). There is a varied range of units, for an air flow between 150 and 2000 m\({}^{3}\)/h, but for this specific application, the model with 800 m\({}^{3}\)/h was selected.