Reduce Decomposition Of Glycerin
You could try the mechanism behind mist fountains or other "cold fog" machines:



These use an ultrasonic oscillating diaphragm to produce a fine mist of room temp water, no heating performed. The resulting vaping machine would be larger and require more power, but wouldn't have the harmful aldehydes inherent in current vaping liquids. Nicotine itself is hygroscopic but not really water soluble at room temp, but it can form salts that are water-soluble so it could be introduced to the body this way. Various flavors currently used might be more or less water-soluble. Finally, the fog, being simple water vapor, wouldn't be visible when exhaled which is one reason the glycerol compounds are used; they produce a "smoke" that dissipates more quickly than tobacco smoke.