Mathematical modeling and evaluation of new long single slope still for utilization of hot wastewater

Abstract Various thermal power systems use water as a coolant and their discharge contains enormous amount of energy, which remains unutilized and released into the atmosphere to its remarkable extent. The aim of present work was to propose a model to recover this unutilized energy by developing an efficient distillation system which may be coupled in between the output of thermal power generation system and chiller unit. For the purpose, analytical model was developed and obtained results were found to be in good agreement with experimental observations. In the proposed model, long still has been developed and fed with a hot wastewater having temperature of 70 ± 1 °C at a constant flow rate of 1100 l/h. It was observed that the theoretical and experimental results are almost comparable within 0.6–1.2 m length and variation of about 20.91% is observed below 0.6 m length of developed still, which might be due to higher temperature of inlet water at the entry point and unaccountable variance in ambient conditions. As a concluding remark, it has been observed that the proposed still produces maximum yield toward the inlet and decreases toward the outlet, which may be due to the lowering of water temperature with length, which further reduces rate of evaporation and yield.