Ventilation Opportunities in Air Conditioning Systems

This work applies Online Building Energy Simulation and Optimization programs (BESOO) to determine the energy conservation potential of ventilation when using air conditioning. The default ventilation is 10 changes per hour, equivalent to 1,560 CFM per 100m2 apartment. Ventilation saves more than 70% of energy for cooling at 25°C-26°C in Jerusalem and 25% in Tel Aviv. When cooling at 26°C, ventilation reduces the Heat Index discomfort period by 99% (from 911 to 11 hours per year) in Jerusalem and 55% in Tel Aviv. The default ventilation in this work was 10 changes per hour; however, after 4 changes per hour (600 CFM for a 100m2 apartment), the impact of increased ventilation volume is very low. When operating at the optimum comfort (OCAC) cooling temperature, the ventilation saves 74% of cooling hours in Jerusalem and 40% in Tel Aviv.