Title: Multi source cooling control algorithm

Abstract— This paper describes how the automation team at ENI Green Data Center (GDC)1 solved the problem of con-trolling the temperature inside a data room that can be air cooled both with direct free-cooling and with water-based chillers and heat exchangers using a sliding mode control design. They created an algorithm which pro-vided: 1. a directional, incremental “walking ” function to seek out and test alternative solutions, biased toward a preferred solution, 2. stabilization on an optimized solution, 3. a destabilization function to retest the solu-tion periodically without allowing jitter, and 4. a meth-od of changing preference to autonomously reoptimize for another configuration.