This paper characterizes industrial waste pressure as a reclaimable form of energy, analyzes the effectiveness of ‘vortex tube energy separation’ in recovering waste energy from low pressure sources, and explores experimentally the possibility of multiple flow structures (like Reverse, Elbow, T-flow or VT-flow) inside vortex tube in a low inlet pressure regime. First time, a study of flow modes in low pressure vortex tubes with small cold fractions has been presented which yielded quantitative confirmation of simple one dimensional model for these flows allowing both predictive capabilities and guidance in design.