Experimental studies on absorption heat transformer coupled distillation system

A Vapor Absorption Heat Transformer (VAHT) working with water–lithium bromide (LiBr) solution, coupled with a seawater distillation system of 5 kg/h distilled water capacity has been tested to evaluate its performance. Operating parameters such as the heat source, condenser, evaporation temperatures, gross temperature lift and feed water flow rate were varied. The influence of these operating parameters on the performance parameters namely the coefficient of performance (COP), absorber heat load, distillate flow rate, recovery ratio and overall specific thermal energy consumption (OSTEC) was obtained. The results of the operation of the laboratory scale pilot unit shows, that for heat delivery temperatures up to 100 °C, temperature lifts up to 20 °C could be realized. For this system, the COP of 0.3 to 0.38 was obtained with the maximum distillate flow rate of 4.1 kg/h and a recovery ratio of 0.17 to 0.23, under tested conditions. The distilled water obtained was found to be within the permissible limits of properties and dissolved salts and solids for potable water.

Research Highlights
► An absorption heat transformer for distillation of seawater has been tested.
► A COP of 0.38 has been realized for the experimental heat transformer system.
► Temperature up to 100 °C with a maximum temperature lift of 20 °C has been achieved.
► A recovery ratio of around 0.2 has been obtained for the distiller operated with VAHT.
► The quality of the distillate water is found safe to be used as drinking water.