Fuzzy ventilation control for zone temperature and relative humidity

Many nondomestic and domestic buildings, built around the world, use natural means to provide ventilation for indoor air quality and thermal comfort. The fuzzy ventilation control strategy aims to use the free cooling and dehumidification available due to differences in zone and ambient conditions. This can be achieve by changing the proportion of fresh air entering the heating, ventilation and air conditioning (HVAC) system and hence the controlled zone. The fuzzy ventilation controllers also aim to maintain the zone conditions at a preferred set point which lies between the upper and lower set points. The upper and lower set point limits and the preferred set point for fuzzy ventilation control purposes are set to ensure occupant comfort. Hence when the fuzzy ventilation control strategy is not capable of maintaining the zone conditions within the upper and lower set-point limits the HVAC plant become active. Simulations results using the fuzzy ventilation control strategy are compared with normal plant considering PID controllers with upper and lower set point limits for each controlled parameter. This benchmark comparison is used to assess the benefits of using the fuzzy ventilation control strategy.