SBIR Phase I: Shape memory alloys with large latent heat low fatigue for solid-state refrigeration

This Small Business Innovation Research Phase I project focuses on developing thermoelastic materials with long fatigue life, suitable for refrigeration and cooling applications. Thermoelastic cooling (TC) is a new technology based on the latent heat generated and absorbed during the stress-induced phase transformation in a shape memory alloy (SMA). The efficiency of the thermoelastic cooling process is high, with a coefficient of performance (COP) estimated at 11.8, which is double that of state-of-the-art vapor compression technology. This technology, however, has drawbacks in its current preliminary form; these include a relatively low latent heat (~12 kJ/kg) and a limited fatigue life. The objective of this project will be to develop a new SMA material for TC applications, which features long fatigue life and small thermal hysteresis. Novel methods, such as thick-film synthesis and micro-indentation, will be used to prepare samples. The resulting materials will then be characterized based on hysteresis, latent heat, and stress-strain relationships. The broader impact/commercial potential of this project is huge, with the resulting products having the potential to displace vapor compression technology in a variety of residential and commercial cooling and refrigeration applications. If successfully commercialized, this technology could reduce U.S. annual primary electricity consumption by up to 3.73 quads in 2030. Since the thermoelastic cooling method completely eliminates the need for an entire class of high global warming potential (GWP) greenhouse gases, namely hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), the total CO2 savings could be as high as 368 million metric tons. A successful commercialization and deployment of products based on the TC method could create hundreds of quality domestic jobs, with most coming in the manufacturing sector.