Optimal scheduling of HVAC operations with non-preemptive air distributions for precooling

The in-building section of a Heating, Ventilation and Air Conditioning (HVAC) system is a major contributor to its overall energy consumption. This paper looks into the energy savings at the supply fan which takes up to 30% of HVAC in-building energy consumption, while energy consumptions at the chilled water pump and the chiller are also taken into account. By elongating the cooling process, the energy consumption can be significantly reduced due to the nonlinear feature of the fan power consumption. To ensure that a computed assignment of mass flow rates is practically feasible, we present an efficient way to check whether there exist a fan supply pressure and room damper openings to realize those mass flow rates. Simulations are used to illustrate the effectiveness of our precooling approach.