Building comfortability and computation schedulability: A comparative study

Many energy consuming devices, especially thermostatically controlled electrical devices (TCED) such as air-conditioners, room heaters and refrigerators, have a periodic execution profile, tempting us to draw an analogy between the allocation of electrical power to TCEDs vis-à-vis the allocation of CPU time to computational tasks. The resulting mapping naturally leads us to make use of traditional real-time scheduling policies such as earliest deadline first (EDF) and least slack-time first (LSF) (and the associated schedulability analysis) in managing TCEDs to deal with energy management and peak power constraints. However, the analogy is not without detractors: the execution time (interval when a TCED is ON) and the period of a TCED are dynamic. In this work, we critically examine the similarities and the differences between real-time tasks and TCED activities. The focus of this work is to analyze the ability of scheduling policies from the real-time domain to attain desired thermal comfort within designated spaces, which we term as comfortability.