Tilla?mpning och simulering av naturlig ventilation
Potential fo?r utnyttjande i kontorsrum
Mechanical ventilation is the most common type ofventilation in newly constructed office buildings. Therehas been an interest to utilize natural ventilationinstead of mechanical ventilation among architects andHVAC consultants in recent years. This is due to thesize of mechanical ventilation systems, which arespace consuming. The mechanical ventilation system isalso complex and requires maintenance. Furthermore,the fan uses a considerable amount of energy. Naturalventilation is an alternative not affecting the rentablefloor space. The basic idea of natural ventilation is touse a technique where natural forces such as wind andthermal gradients fully handle the ventilation.The software program IDA ICE was used to simulatethe natural ventilation by advanced window control inoffices and to investigate if natural ventilation is agood option to conventional systems regarding indoorclimate and energy use. The indoor temperature andthe concentration of carbon dioxide control thewindow opening. A CAC (Clean Air Control)- sensorwas also used instead of a traditional CO2-sensor,which is a sensor that regulates the airflow accordingto the level of air pollution.The results show that natural ventilation with advancedwindow control cannot always achieve the regulatoryrequirements for the highest carbon dioxide content of1000 ppm, since the airflow is not sufficient. On theseoccasions a fan is required to provide a good indoorclimate. An interesting observation is that the energyuse for heating is only 38% larger for the office roomswith natural ventilation compared with mechanicallyventilated offices. Even though the heat energy arereleased to the outdoor environment and notrecovered in the naturally ventilated room.