Energy Technology

Permanent URI for this collection

http://etd.aau.edu.et/handle/123456789/51

Browse

Browsing Energy Technology by Author "Beniam Getasetegn"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Investigation of Exhaust Gases Driven Absorption Cooling System Case Study on Gambella, General Cargo Ship
    (Addis Ababa University, 2025-06) Beniam Getasetegn; Solomon Teklemariam (PhD)
    In shipping transportation emission reduction has been a great concern for the last decades own to various reasons. Due to increment of oil prices, shipbuilders have been inspired to rise the vessel’s overall fuel efficiency. Currently, these situations are initiated by emission controlled areas as well as taxation of CO2. Recovering waste heat from low grade energy through vapor absorption refrigeration system is a promising way to improve engine efficiency and fuel consumption. In this thesis, utilization of exhaust gas from marine engines as a heat input to vapor absorption system is examined using marine vessel Gambella as a case study ship. The absorption cycle uses H2O−LiBr solution as a circulating fluid. An exhaust gas analysis is computed based on six months of engine performance data and then thermodynamic analysis is computed and simulation analysis is performed using Excel for vapor absorption system. This thesis focuses on performance enhancement of single effect vapor absorption system. By adding mixing chamber, flash gas removal and liquid suction heat exchanger into a single stage system, system performance is raised. Thermodynamic analysis is computed to compare the increment of performance on proposed cycle with ordinary and combined cycle. Simulation result shows that a proposed cycle COP is increased considerably by 38.23% and 3% relative to ordinary cycle and combined cycle respectively. Adding of vapor mixing chamber and flash gas removal accounts 35.23% increment on system performance and the remaining 3% is accounted by liquid suction heat exchanger. From the results the proposed cycle also considerably increased the cooling effect in an evaporator as well as an overall efficiency of marine diesel engine of the case study ship between 4 – 9%. Hence, introducing vapor mixing chamber and liquid suction heat exchanger to an ordinary cycle is a novel enhancement. Environmentally, utilizing the absorption system throughout sailing will diminish fuel utilization by 82.5 ton/year with fuel cost saving by 57,188.18 $/year and this results a payback period of 7 years for investment cost. This, in turn, decreasing emissions of NOX, SOX as well as CO2 by cost effectiveness of 2.88 $/kg, 18.86 $/kg as well as 0.054 $/kg respectively and also reduces about 349.55 and 418.11 tons of CO2e in 100years and 20 years using well to wake approach respectively.