Low-Cost Temperature Control from 160 K to Ambient Temperature Using Liquid Nitrogen Evaporation

Abstract

A low-cost temperature controller that allows variation from 110 K to room temperature of liquid, gas, or solid samples is described. The desired stabilized temperature is obtained within a few minutes by controlling the current through an electrical resistor immersed in a liquid nitrogen reservoir. The stability of the temperature ranges from less than ± 0.5 K at temperatures higher than 230 K to ± 1.1 K at 160 K. The maximum consumption of liquid nitrogen for cooling a glass photochemical reactor was less than 0.60 liters per hour at temperatures lower than 160 K, about 0.4 liters per hour at 160 K to 190 K, and decreases considerably over 200 K. A linear dependence of the temperature with a flow of evaporated gas was found (240–285 K). This device can be used easily in experiments that need low temperature regulation, involving gas–surface interactions, adsorption–desorption processes, heterogeneous atmospheric chemistry, thermodynamics of gases, and so forth.