Intelligent energy management and control system (EMCS) in buildings offers an excellent means of reducing energy consumptions in HVAC systems while maintaining or improving indoor environmental conditions. This can be achieved through the use of computational intelligence and optimization. The paper thus proposes and evaluates a model-based optimization process for HVAC systems using evolutionary algorithm for optimization and artificial neural networks for modeling. The process can be integrated into the EMCS to perform several intelligent functions and achieve optimal whole-system performance. The proposed models and the optimization process are tested using data collected from an existing HVAC system. The testing results show that the models can capture very well the system performance, and the optimization process can reduce cooling energy consumption by about 11% when compared to the traditional operating strategies applied.

Filters are used in heating, ventilation, and air-conditioning (HVAC) systems for both commercial and residential buildings to protect the equipment and improve indoor air quality in conditioned spaces. Although there are many benefits of using the air filter in an air-conditioning system, the resistance associated with it can increase fan energy use and may adversely affect air-conditioning system performance and efficiency. The paper explores the impact of air filtration on energy consumption for a typical air-conditioning (AC) system with constant- or variable-speed fan. A whole building simulation model is used to simulate the annual energy consumption for various air-conditioning system capacities, different levels of filter cleanliness, and various filter minimum efficiency reporting values (MERV). The results indicate that with a constant-speed fan, the cooling energy use increases as the filter gets dirty over time and the energy use in the fan may increase but this depends heavily on the investigated fan performance curve. With a variable-speed fan, the fan energy use increases with a dirty filter but the cooling and heating energy uses are slightly affected. The fan energy use rise due to the dirty filter depends mainly on air system capacities, filter MERV ratings, and the degree of the filter cleanliness.