Experimental Study On Semiconductor Thermoelectric Generation For LNG Cold Energy Recovery Technology

Urgent social problems like energy shortage and environmental pollution have become increasingly prominent, having accelerated the transformation of the energy structure. Due to natural gas’(NG) rich amount of storage, cleanness, high utilization efficiency, it is recognized as a high-quality alternative energy sources. As a country rich in coal but lack in gasoline and NG, China has increased investment in Liquefied Natural Gas(LN G) receiving station and LNG import by sea. LNG is stored at the temperature of-162℃ and will release enormous cold energy in the gasification process. LNG cold energy has been widely applied in electricity generation, air separation, dry ice manufacturing, refrigerating cabinets, cryogenic grinding, desalination, sewage treatment and so on.However, these LNG cold energy recovery technologies are of complex processes, difficult maintenance, much noise. Driven by the temperature difference from cold and heat sources, t hermoelectric power generation is a sort of technology transforming heat into electricity. This technology can be newly applied in the LNG cold energy recovery, having overcome the shortcomings of the traditional ones. Therefore, this paper had theoretical analysis on thermoelectric power generation and experimental investigation on generation performance of a single Thermoelectric Generator(TEG) and TEG modules at low temperatures.This experiment was conducted in the cold source range of 213K~273K and in the temperature differce range of 30K~80K. Core components are TEC1-12706 TEGs in the heat transfer experiments platform. A data logger and a camera were used to collect real-time temperatures, voltages and currents, respectively. This experiment was aimed at investigation on the effects of cold source temperature Tc and temperature difference ?T on the single TEG’s generation performance. Based on the original experiment platform, the number of the TEG was changed to investigate the effects on the deviation factor Z of 8-TEG module from Tc and ?T and the effects on the deviation factor Z of modules composed by different numbers of TEGs when Tc=223K, ?T=70K.Based on the experimental data, figures were drawn to display the changes of the performance a single TEG and deviation factor Z of 8-TEG module with cold source temperature Tc and temperature difference ?T, respectively. From these figures, conclusions can be found as follows:(1)The TEG resistance, TEG voltage and load electric power all increase with the increase of the cold source temperature Tc or the temperature difference ?T, but the increase extent of the load electric power with the increase of cold source temperature Tc is not obvious;(2) Deviation factor Zu and Zp of the 8-TEG module increases and Zr keeps stable with the dcrease of the cold source temperature T or the increase of the temperature difference ?T, respectively;(3)When the cold source temperature Tc=223K and the temperature difference ?T=70K, deviation factor Zr of TEG modules almost keeps stable at 1, Zu increases linearly and Zp increases with a quadratic function trend with the increase of the numner of the TEG modules, respectively.