Three conceptual designs of a cold trap with integrated sodium-air HX (heat exchanger) and sodium sodium HR (heat recuperator) were considered for the KASOLA (KArlsruhe SOdium LAboratory) sodium loop in Karlsruhe, Germany. All designs consist in the bottom part of vertically placed stainless steel wool packages used to retain the impurities from sodium. The upper part contains the sodium-air HX and the sodium-sodium HR. The purification function of the cold traps was laid out so that it can serve for the complete service life time of the experimental facility quasi maintenance-free. Regarding the sodium cooling and the heat recuperation three designs have been proposed and analyzed, and the best solution has been chosen. The study is focused on the layout and the optimization of the cold trap with respect to the optimal wire mesh dimensioning (e.g. wire mesh radial size, sodium residence time, pressure loss, etc.), optimal solution for the sodium heat recovery and for the air cooling system. The final design chosen has efficient sodium purification, larger purification rate, heat recovery of up to 90% and low operating costs. This optimized design was further fine tuned and the cold trap was manufactured and installed in the KASOLA facility. (C) 2017 Karlsruhe Institute of Technology. Published by Elsevier Ltd. All rights reserved.