There is a gap in literature on comparisons between different MPC optimal control formulations and solver choices for the same building HVAC system. Mixed Integer Nonlinear (MINL) formulations are rarely considered, despite being the most physically accurate way to represent HVAC systems. This work compares several MPC formulations, including Quadratic, Nonlinear, and MINL, applied to a case study building and investigates benefits and challenges of MINL MPCs from practical perspectives. Ten different MPC formulations were developed and implemented using Pyomo. Then, a detailed emulator model was developed using open-source Modelica libraries and used with BOPTEST to assess the performance of each MPC. Results show that convergence and control switching behaviours of MINL MPCs are sensitive to formulations, initialization approaches, solver selections, and solver parameters. Thus, they require significant effort for tuning. However, a very well-tuned MINL MPC performed similarly to successful Nonlinear MPC formulations.

Residential and commercial buildings are responsible for almost 50% of the total electricity consumption in Egypt. This percentage is expected to increase due to the global warming effect. This work deals with the cooling energy use reduction strategies for residential buildings compatible with the Egyptian market accounting for the global warming effects. A study in the Egyptian market was done to explore the best available technologies in the Egyptian market. A series of dynamic simulations were executed in each city to optimize the building envelope using the best available technologies to reduce the cooling needs. Financial, energetic and environmental factors were taken into consideration, and comparative analysis was done to assess the best alternatives. The double wall with air gap and insulation on the outside was found to be the best alternative in all the cities. Moreover, simple measures to further reduce the cooling energy need were explored, such as the usage of more efficient lighting and night ventilation. This work led to an average reduction of 40% in the cooling energy needs and CO₂ emissions across the three cities, with a maximum discounted payback period down to 6.3 years. Future weather files adapted to climate change were generated, and the selected passive strategies were tested to assess the validity of such strategies in the future. The cooling energy needs are expected to increase by 39%, while the peak cooling loads are also expected to increase by 23% by 2080, rendering the current installed HVAC systems undersized.