Geothermal Energy Concept Applied to All-Air HVAC System

Abstract The novel method of combining geothermal energy with an all-air heating, ventilation, and air conditioning (HVAC) system is presented in this work. A building in Lebanon serves as the case study, which aims to determine the necessary mass flow rate for the conditioned space. Rather than permitting ambient air to enter the Air Handling Unit (AHU) directly, the plan calls for a 2-meter-deep geothermal duct to be buried. By adjusting the air temperature prior to it entering the AHU, this geothermal duct helps to improve the efficiency of the HVAC system and lowers the AHU’s yearly energy usage. Furthermore, the idea guarantees that there will always be 100% fresh air available, which means that the all-air HVAC system won’t need to recycle treated air from the conditioned space—also known as return air. According to the findings, the heat rate of the geothermal duct may reach 210 kW, which would result in a large decrease in CO2 emissions and cost savings for the HVAC system.