Air-source heat pumps typically deliver 1 1/2 to three times more heating energy to a home than the electric energy they consume. National Institute for Standards and Technology (NIST) researchers are working to improve the performance of air-source heat pumps even further by providing engineers with computer-based tools to optimize heat exchanger designs.
The researchers developed a testing apparatus that uses a high-resolution camera to track the motion and distribution of air flow in finned-tube heat exchangers. Data from these laboratory experiments are being compared with computer simulations of air flow performed with computational fluid dynamics software. Once accurate models are developed and validated, engineers could use them as the basis for design changes to coil assemblies and refrigerant circuitries to accommodate the existing air distribution.
The program could increase finned-tube heat exchanger heating or cooling capacity by five percent, improving heat pump efficiency. Such improvements could allow manufacturers to reduce the heat exchanger size, thus reducing material cost and the amount of refrigerant needed.