Enhancing the performance of a spray flash evaporation integrated with evacuated tube desalination system

Abstract

Numerical analysis for heat exchanger for spray-assisted low-temperature desalination system is presented for an existing low-temperature desalination unit at Arusha Technical College (ATC). The current desalination unit at ATC has two suction fans and a water pump in the condensation unit where significant amount of energy is consumed. So, it will be impractical to implement such a type of desalination system in remote areas where there is limited access to electricity. The study aims to come up with a suitable model for the replacement of the current condensation unit due to high energy consumption. The heat transfer phenomena have been analyzed to understand the effect of mass flow rate, tube length and diameter in a shelland-tube

heat exchanger (STHX). A Math CAD model was developed using the Delaware method to obtain the mentioned parameters. The results show that the pressure drop is very low from all STHX configurations, while the heat transfer coefficient seems to be maximum in the smallest diameter within the largest tube length heat exchanger. The maximum possible energy will be extracted by the STHX from the steam while it condenses. According to the results, as long as over-design is considered the proposed system can be implemented with the minimum effect of 5.968 to 10.688 kWh energy consumption. The energy-saving of the proposed system is about 8.856 kWh as the replacement of the STHX from the existing condensation unit. While the current system energy is consumed about 14.824 to 19.544 kWh in a single day of operation. Also, the proposed system will improve the system workability to the remote communities in future implementation.