A multipurpose desalination, cooling, and air-conditioning system powered by waste heat recovery from diesel exhaust fumes and cooling water

The role of cooling and air-conditioning systems in submarines is assessed as indispensable, and a reliable water supply is essential for both crew and equipment. At the same time, the large amounts of high-temperature exhaust fumes discharged from submarine engines provide an excellent opportunity to recover and apply this waste energy in required applications. This paper introduces a novel multipurpose desalination, cooling, and air-conditioning system to recover waste heat from both the exhaust fumes and the cooling water of submarine engines. The whole system is mathematically modelled and analysed based on the actual thermo-physical parameters of the engine's exhaust fumes. The analysis indicates that at cooling water flow rate of 0.25 kg/s and diesel exhaust mass ratio (X) of 0.25, the mass flux through the membrane in the desalination unit reaches 8.3 kg/m2h. Whereas for the same cooling water flow rate, the mass flux increases by 2 kg/m2h as X increases from 0.25 to 0.3. The results also show that a 160 kW cooling power is only achievable when X varies between 0.8 and 0.95 and the refrigerant mass flow rate is in the range of 0.27 kg/s to 0.34 kg/s.