Investigation of thermodynamic performance based on the humidity effect in the aircraft environmental control systems

Some environmental parameters, such as pressure, temperature, humidity and velocity, of air are important for passengers, stayed in aircraft cabin. These values change with altitudes, also atmospheric conditions. The humidity values, especially one of these values, inside aircraft not only affect the indoor air quality directly but also may damage electronic equipment. Environmental control systems (ECSs) have a very important role to control temperature and humidity and to eliminate the negative effects such as increasing fossil fuel use and accordingly global warming potential due to the irreversibilities in the system. In this study, thermodynamic analyses of the effect of humidity on the indoor air quality for a commercial airplane were performed in different altitudes. Energy efficiency was obtained between 93.6% and 55.2% and exergy efficiency was obtained between 49.6% and 23.14% at the altitude range of 0-12,192 m.