Magnetocaloric Generator for Waste Heat Recovery

A 2008 DOE report [1] indicated that up to 903 terra-btu per year of unrecovered low-level industrial waste heat IWH) in the US is available for conversion to electricity. Converting this heat to electricity at 30% conversion efficiency would produce ~9 GW of electric power, an equivalent to about 4.5 Hoover Dam outputs. Efficient low-cost recovery of low-level IWH at significant scale could displace a large number of fossil-fuel power stations and avoid the concomitant production of CO2 as well as other green-house gases GHG) and pollutants. Based on DOE target cost of $1/We, there is a potential $9B market for electricity generation from low level IWH. Traditional means for production of electricity from heat such as the steam cycle, organic Rankine cycle ORC), Kalina cycle, all have efficiencies <40% of Carnot limit, which makes them marginal for conversion efficiencies of >20% from low-level IWH. Alternative established technologies such as thermoelectrics, thermionics, or piezoelectrics are about an order of magnitude short of each of the DOE efficiency and cost targets. Aqwest proposes to develop a magnetocaloric generator MCG) offering thermodynamic efficiency up to ~80% of Carnot limit, which enables ~30% conversion efficiency of low-level of industrial waste heat IWH) at 450F 232C) to electricity. Our previous work indicates that the DOE cost target of $1/We is within reach. In Phase I we will assemble and parametrically test a demonstration unit to map out the operating regime and to anchor our model suite. Plans to further develop and exploit the technology in Phase II will be developed.