Economic Feasibility Assessment of Split-Type Air-Conditioning Retrofits in University Buildings: A Simulation-Based Methodological Framework

This study evaluates the economic feasibility of retrofitting split-type air-conditioning systems in a university administrative building in a hot-humid tropical climate in Colombia, addressing the need for cost-effective energy-efficiency strategies in such contexts. A measurement-calibrated building energy model was developed using DesignBuilder and EnergyPlus, and a baseline scenario with low-efficiency fixed-speed split units was compared against three retrofit scenarios with higher-efficiency units defined by market-available COP levels. A 10-year life-cycle cost (LCC) analysis was conducted using a discounted cash flow approach, incorporating investment costs, operation and maintenance expenses, electricity tariff escalation, and equipment performance degradation, complemented by a parametric sensitivity analysis. The results show that air-conditioning systems account for the majority of total building electricity consumption, and that retrofit scenarios reduce cooling energy use by approximately 45–53% relative to the baseline. All retrofit options yield lower life-cycle costs despite higher initial investments, achieving total LCC reductions of up to 30%. Sensitivity analysis indicates that the economic ranking of alternatives remains stable under significant variations in electricity prices. Overall, the proposed framework provides a robust and transferable approach for assessing HVAC retrofit strategies, supporting informed decision-making for energy and cost optimization in buildings located in tropical climates.