Experimental Analysis of LNG Cold Exergy Recovery Using Thermoelectric Generators

A dedicated experimental setup was designed and constructed to investigate the performance of thermoelectric generators (TEGs) operating under cryogenic temperature conditions, representative of the heat recovery process during liquefied natural gas (LNG) regasification. The test bench enables precise control of both hot- and cold-side temperatures, simulating real operating conditions of mobile LNG systems. Six types of commercial TEG modules were tested at two hot-side temperatures (283 K and 340 K) and variable cold-side temperatures (150–260 K). The results showed that higher temperature differences significantly improved electrical power generation and conversion efficiency. For one of the TEGs, the electrical power and efficiency nearly doubled compared to the case with a hot-side temperature of 283 K. As the cold-side temperature increased, both performance indicators decreased almost linearly, as expected, with the lowest gradients observed for one of the TEGs, indicating the highest potential for total exergy recovery. These findings indicate that TEGs can effectively recover cryogenic heat during LNG vaporization. Scaling the system to practical applications shows that electric power exceeding 1 kW can be achieved in railway transport and up to 10 kW in marine applications, making this approach technically and economically viable for large-scale mobile LNG systems.