Utilization of waste hot air of medical oxygen plant in solar desalination unit employing jet impingement air heater for water production

Abstract

Many oxygen plants have been established specially during COVID-19 period and they are still serving for medical needs. The objective of the present work is to utilize solar and waste thermal energy of medical oxygen plants for water production. Humidification–dehumidification desalination (HDD) has been found suitable for this objective due to low temperature energy need during the process. The layout of an HDD unit has been presented to utilize waste heat, specially when solar energy is not much effective or absent. The system has been configured with a jet impingement solar air heater and a packed bed humidifier. A mathematical model has been developed and validated with the results of our experiments. A comparative study of the proposed unit (HDD-O2) and a conventional unit has been performed in terms of yield and gained output ratio (GOR). The optimum flow rates of working fluids found in the range 0.03–0.04 kg/s and the temperature of air and water resulted in a continuous gain in yield. The average yield and GOR of the HDD-O2 unit were found to be 8.5 kg/d and 1.1 that could reach up to 11 kg/d and 1.4, respectively. The HDD-O2 unit provided yield at the cost of 0.04 $/kg with a payback period of 1.73 years. The findings of the present work indicated the suitability of the HDD-O2 plant for water production.