4327 -- Second Law Analysis of Multi-Stage Lithium Bromide/Water Absorption Heat Transformers PDF

Heat transformers have good potential for recovering waste heat and upgrading it to higher temperatures for industrial processes. Thermodynamic second law analysis in conjunction with first law analysis gives a premium to the consideration of the quality of energy over the quantity involved in a thermal system and can lead the way to improve the system's performance. In this study, performance comparisons of single-, double-, and triple-stage absorption heat transformers (AHT) using a lithium bromide/water (LiBr/ H₂O) solution as the working fluid were conducted and analyzed on the basis of the first and second laws of thermodynamics. Simulation of these systems was employed to evaluate the first law performances, while the thermal properties, entropy, and exergy of the working fluids were also calculated to analyze the second law efficiencies under different operating conditions. The results obtained here can provide some theoretical bases for the optimal operation and design of real AHT systems.

Units: SI