An Algorithm for Mixed-Integer Optimal Control of Solar Thermal Climate Systems with MPC-Capable Runtime

This work presents an algorithm for solution of Mixed-Integer Optimal Control Problems (MIOCPs) for Solar Thermal Climate Systems (STCSs) with MPC-capable runtime. We implement the so-called Combinatorial Integral Approximation (CIA) algorithm for a model of an STCS of a building that incorporates an adsorption cooling machine and apply the algorithm within a numerical case study to solve a Mixed-Integer Non-Linear Program (MINLP) resulting from an MIOCP for the system. We compare the results of the CIA algorithm to those of a general MINLP solver and show that our algorithm achieves comparable solution quality at a runtime that is up to 1000 times smaller.