Study On Cold Finger Method Based On Miniature Thermoelectric Cooler

Phase change materials have been widely used in aerospace,energy-saving for buildings and other applications due to their advantages such as large latent heat value and stable phase change temperature.However,problems such as supercooling and phase separation of phase change materials have limited their practical usage.This paper studies the supercooling of hydrated salt,a commonly used inorganic phase change material,and proposes a new method to effectively inhibit supercooling.This article first analyzed the problem of supercooling of hydrated salt materials in principle and then compared the commonly used methods to inhibit the supercooling of hydrated salts and the advantages and disadvantages of various methods in practical applications.Combining the problems faced by the practical application of hydrated salts and the advantages of thermoelectric refrigeration,a new cold finger method based on miniature thermoelectric cooler module was proposed to solve the problem of supercooling of hydrated salt.The cold finger experiment was performed in a test tube.The results showed that this method could successfully trigger the solidification of Na₂HPO₄·12H₂O solution under 33°C water bath and the supercooling degree of Na₂HPO₄·12H₂O solution is only 2°C.The subsequent 10-cycle experiment powered by AAA battery showed that this method has low energy consumption and can trigger the solidification of hydrated salts stably.46-hour heat storage using supercooled Na₂HPO₄·12H₂O without insulation was also demonstrated with on-call crystallization using the thermoelectric cold finger method.To verify the feasibility of the practical application of the cold finger method based on the micro thermoelectric cooling module,a copper box,and foamed copper were used to obtain a packaging module which contains Na₂HPO₄·12H₂O material and a thermoelectric cooler.The melting-solidification cycle of the packaging module was performed 1000 times and the temperature was controlled by a temperature control device.The water bath test showed that the cold finger method based on miniature thermoelectric cooler module can still successfully trigger the solidification of the hydrated salt material after 1000 cycles.