Browsing by Author "Muhunzi, Amour"

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    Enhancing the performance of a spray flash evaporation integrated with evacuated tube desalination system
    (NM-AIST, 2021-02) Muhunzi, Amour
    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.
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    Numerical Analysis of Heat Exchanger for Spray-Assisted Low-Temperature Desalination System
    (Hindawi, 2020-12-12) Muhunzi, Amour; Jande, Yusuph; Machunda, Revocatus
    A numerical study for heat exchanger for spray-assisted low-temperature desalination system is presented for an existing low-temperature desalination unit at Arusha Technical College. This is aimed at recognizing the effect of mass flow and physical parameters like tube layout (diameter and length) on the overall heat transferred and the pressure drop in the shell-and-tube heat exchanger (STHX), as well as the impact of these parameters on the heat transfer coefficient and the overdesign of the STHX. Also, the study provides a suitable mathematical model for the replacement of the current condensation unit which tends to reduce energy consumption by reducing some of the electrical components in the system. A Math CAD model was developed using the Delaware method to obtain the mentioned parameters. The results show that at 0.8 kg/s flow rate a maximum heat transfer coefficient of 23212 W/m2K is achieved in a minimum diameter of 10 mm within a maximum tube length of 1000 mm heat exchanger and the pressure drop seems to be very low in a range of 0.328-0.957 Pa from all configurations. The configuration with 1000 mm tube length and 10 mm diameter performed well on the mass flow of 0.3 kg/s-0.8 kg/s by providing a suitable overall heat transfer coefficient of 2306-2539 W/m2K, while 12.8 is a maximum overdesign coefficient achieved on 0.8 kg/s mass flow. The study results show the possibility of using STHX instead of the current condensation unit in implementing a proposed system layout with the minimum effect of energy consumption.