Development of Hybrid Optimal Controller for Building AC Compressors

Energy consumption of AC systems poses a large problem, as well as great opportunity for energy efficiency. A simple, yet sophisticated, way to achieve higher energy efficiency is by properly controlling the AC system. Conventional AC control systems operate under binary conditions being either on or off depending on interior temperature set point. This method of AC control suffers in both energy efficiency and temperature control, allowing the temperature to swing within the controlled space. The approach presented in the paper succeeds in achieving both improved thermal comfort and energy savings by operating the system more efficiently. The genesis of the research is a controller method developed by Abbasi et al [1] for use in refrigerator appliances which found great success in reducing energy consumption (by approximately 7 percent) and greatly enhancing temperature control. This controller does not try to control the temperature of the system. Instead, it uses a more relevant thermodynamic property; system excess enthalpy. Based on extensive multilevel modeling results, the proposed control algorithm can reduce building cooling energy by as much as 5 percent while providing considerably better temperature and humidity control at zero added production cost.