A neural network approach and thermodynamic model of waste energy recovery in a heat transformer in a water purification process

• Published in: Desalination Vol. 243; no. 1; pp. 273 - 285
• Main Authors: Hernández, J.A., Romero, R.J., Juárez, D., Escobar, R.F., Siqueiros, J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-07-2009; Elsevier
• Subjects: Absorption heat transformer; Applied sciences; Chemical engineering; Chemical thermodynamics; Chemistry; Computer simulation; Estimates; Exact sciences and technology; General and physical chemistry; General. Theory; Heat exchangers and evaporators; Heat pumps; Heat recovery; Heat transformers; Mathematical analysis; Mathematical models; Neural network; Neural networks; On-line systems; Pollution; Thermodynamic model; Thermodynamic models; Water purification; Absorption heat transformer; Heat pumps; Neural network; Thermodynamic model; Heat recovery; Purification; Heat pump; Unsteady state; Energy recovery; Modeling; Steady state; Design; Condenser; Evaporator
• DOI: 10.1016/j.desal.2008.05.015
• EISSN: 1873-4464
• ISSN: 0011-9164

A theoretical comparison of neural network (NnM) and thermodynamic (ThM) models is carried out to estimate on-line the coefficient of performance (COP) in an absorption heat transformer integrated with a water purification process (AHT–WP). The NnM has been computed for16 variables measured by sensors (input and output temperatures for each of the four components absorber, generator, evaporator and condenser; input pressure parameters and LiBr + H
2O concentrations). The ThM estimates the COP values with average temperatures of each component of the AHT–WP. This ThM has been designed for steady-state conditions while the NnM has been developed for steady- and unsteady-state conditions. Both models can be used to calculate the COP values on-line; nevertheless, each model has its own advantages and disadvantages in the AHT–WP design and control. The waste heat simulated for the experimental water purification system is lower than 1 kW, while temperature and lithium bromide concentration are invariable in huge systems.