24 June 2014
The purpose of this study is to develop an innovative energy-saving A/C controller that can improve the energy efficiency of multi-split type air conditioning system for buildings
(outdoor-air processing VRF system + heat recovery VRF system) operated under low thermal load conditions and/or simultaneous cooling and heating mode. This new A/C
controller consists of the capacity optimization by the real-time prediction of the indoor thermal load based on the predictive functional control method, and the minimization of the
capacity-control loss in simultaneous cooling and heating operations. We examined the energy-saving effect of the new A/C controller by the part-load performance tests made in a testing laboratory and by the field measurements of actual operations of the air conditioning system installed in an existent office building in two years. By careful comparisons of
experimental data obtained with the conventional A/C controller and the new A/C controller, it was demonstrated that 170 % higher annual average COP was achieved by the air conditioning system with the developed new controller.