Modeling and optimization of a novel heat recovery design for thermoelastic cooling systems

The traditional refrigerants used in the vapor compression cycles have significant environmental impacts due to their high global warming potential. To address this challenge, solid-sate cooling technologies without using any aforementioned fluids have been developed rapidly during the past decades. Thermoelastic cooling, a.k.a. elastocaloric cooling, is a new concept, and thus no systematic studies of it have been conducted to date. Heat recovery plays an important role in the performance of the cooling systems, affected by the parasitic internal latent heat loss inside the cycle. A novel heat recovery (HR) scheme was been proposed in our previous study to minimize such parasitic internal latent heat loss. The objective of this study is to further investigate the performance improvement potential of the proposed heat recovery method by introducing the optimization study using the previously validated heat recovery model. The dynamic model details are revisited. The assumptions behind the model are re-examined by using the real thermoelastic cooling prototype geometries and materials properties of nickel-titanium tubes. A multiobjective optimization problem was formulated for the model and solved by MatLab. The heat recovery efficiency and the heat recovery duration were used as optimization objectives. A well-spread Pareto solutions were obtained, and a final solution was chosen with a 6.7% penalty in HR efficiency but six times faster cycle.