Real time closed loop data based estimation and explicit model based control of an air conditioning system implemented in hardware in loop scheme

Domestic air conditioners (AC) are a major source of energy consumption. Based on real time data, the input/output dynamics between electronic expansion valve opening degrees (EEVOD) and evaporator outlet air (supply air) temperature is modeled in this paper. Considering an on/off scenario, the outer loop provides two different references to the inner loop based on heating/cooling needs. This supply air temperature (SAT) influences the room model with ambient temperature and wall dynamics (ordinary differential equations simulated in MATLAB). With safety constraints for superheat (SH) and rate constraints on EEVOD, a multi parametric model predictive controller (mpMPC) is designed to control SAT. A proportional integral cascade control scheme is designed to compare the performance of the mpMPC scheme. In hardware in loop (HIL) environment, both controllers are tested under ambient temperature based disturbance. Using power spent and thermal comfort quantization, it is observed that mpMPC scheme outperforms traditional control strategy.