HVAC Optimized Heat Exchangers Research Project
The U.S. Department of Energy is currently conducting research into heating, ventilation, and air conditioning (HVAC) optimized heat exchangers. The information generated in this study will demonstrate performance improvements that can be achieved through optimization of refrigerant circuitry for non-uniform inlet air distribution.
The tubing circuitry on fin-tube heat exchangers used in residential space-conditioning systems is typically designed assuming uniform airflow through the finned passageways. However, the air flow in installed systems is highly non-uniform, resulting in mismatched refrigerant-air heat transfer that reduces the capacity of the heat exchanger and efficiency of the entire system.
This project seeks to develop a method for determining the air velocity profile at the inlet to the heat exchanger, and an automated tool for determining optimized refrigerant circuitry. Optimizing the tube circuitry for both the heat transfer process and the non-uniform airflow is a complex problem that requires the development new design tools and methods. The first step towards industry acceptance of these tools is to demonstrate their use and benefit in a controlled laboratory experiment.
Research is being undertaken between the Department of Energy and the National Institute for Standards and Technology.
The goal of this project is to integrate optimized heat exchanger designs into new products.
Benefits and Impacts
Successful completion of research may result in a performance improvement for heat exchanger capacity on the order of a 5%, which translates to approximately 2% improvement in system coefficient of performance, or equivalently a 2% reduction in energy consumption.
Finned-tube heat exchangers are employed in space conditioning and refrigerating applications which were responsible for the consumption of over 17 quadrillion British thermal units (Btu) of energy in the United States in 2011. An efficiency improvement of this scale could reduce the nation's energy consumption by more than 350 trillion Btu per year.