Integrating the living wall with the split air conditioner towards indoor heating environment improvement in winter

Employing split air conditioners (SAC) for indoor heating is common, but the poor air quality usually occurs due to lack of fresh air and low relative humidity in winter. The indoor living wall (ILW) has become a reasonable option to refine the indoor heating environment through their purification and photosynthesis. To improve the heating environment, ILW were integrated with the SAC. The system integrating the ILW with the SAC (ILW-SAC) was installed in a common room with referring to the other identical room only having the SAC. The indoor thermal environment and CO2 concentration were tested, while the 72 participants were invited to demonstrate their feelings by using skin temperature measurements. The results showed that ILW-SAC significantly improved the indoor environment by increasing relative humidity by 10.8%, controlling air speed between 0.2 m/s and 0.3 m/s, and reducing CO2 concentration by 49 ppm. ILW-SAC lowered the mean skin temperature by 0.4 °C and let the mean skin temperature closer to the neutral value. ILW-SAC was found to improve the overall freshness sensation and thermal comfort level by about 1.32 and 1.10 respectively. By employing ILW-SAC, the indoor thermal environment and air quality are refined significantly in winter.