Optimal water purification using low grade waste heat in an absorption heat transformer

A proposal for rational energy saving using wasted heat is showed in the present paper. Thermodynamicmathematical model is presented like an effort for water purification from waste heat. This paper describes computing results of heat transformer operation for water purification using low grade waste heat. Equations, parameters and simplifications used in the model are briefly described. The main parameter of the carried out study is the coefficient of performance (COP) defined for reversed heat pumps and the second main parameter is absorber temperature, both parameters has been showed and correlated between them. Main objective of this work is to show the optimal operating condition for different process which deliver low grade waste heat and requires water purification. Assisted computing simulation was used for obtain these results. The main conclusion is an ecological proposal for optimal recover of low grade waste heat. Many operating conditions are showed in graphical form and discussed for different environment conditions.

Theoretical behavior of possible operating conditions for an ecological water purification system was shown. The proposal system was theoretically evaluated with low grade energy with inlet temperatures from 65 to 80°C, could be from a source of industrial waste heat. Surroundings for condensate the working fluid remain for the calculations between 25 and 30°C, for guarantee absorber temperature higher than 100°C water purification. Absorber temperature for the system is the power for simple distillation of impure water, with values from 105 to 115°C which can be able for purification of brackish water. The recycled energy for latent heat of purified water purification system has a benefit effect in coefficient of performance, with the relative rise value. Enthalpy based coefficient of performance can arise from 0.3 to 0.429 water purification coefficient of performance and in similar way theoretical limit case may rise COP from 0.5 to 1.0.