HO-18-C061 -- Calculating Energy Savings on Air Conditioners in Industrial Facilities Using Simple Physics

This study proposes a simple method to estimate energy savings opportunities using airside economizers in HVAC systems. In industrial and commercial facilities with high internal heat loads cooling is required year round. In facilities that are cooled year-round, space cooling can contribute up to 40% of their energy consumption in a year. Many facilities mix conditioned air with outdoor air year round to maintain thermal comfort even when outdoor air is cooler and drier than return air. By installing airside economizers, "free cooling" can be achieved which will result in energy reduction. To analyze the energy reduction from installing air-side economizers a simple spreadsheet is developed that compares return air conditions (e.g. temperature and enthalpy) to outdoor air conditions. The calculations show installing an air-side economizer can result in an energy reduction up to 40%.