The researchers designed a new air handling unit with two heat recovery units to reduce energy usage in buildings. By pre-cooling incoming air and preheating outlet air, they decreased the load on cooling and heating coils, improving energy efficiency by 43.75%. This also reduced total irreversibility by 24.56% and improved second law efficiency by 9.27%. Factors like ambient temperature, relative humidity, chilled water temperature, and ventilation amount had the most impact on energy savings.