This study demonstrated the feasibility of an absorption refrigeration system (ARS) that is capable of utilizing the engine exhaust gas of bulk gas carriers as the heat source and generating cooling source either for reliquefaction of the boil-off gas or for heating, ventilating and air conditioning (HVAC). The ARS employed an $NH_3$/$H_2O$ mixture as the refrigerant solution. The process was designed and simulated using the properties of the exhaust gas from the commercially available engines. The coefficient of performance increased with the temperature of the generated cooling source. A decrease in the engine load resulted in a decrease in the exhaust flow rate and, consequently, in a decrease in the cooling capacity. Although the exhaust temperature reached its minimum near the normal continuous rating, the dependence of the cooling capacity on the engine load was not significantly affected. A case study for a liquefied natural gas (LNG) carrier verified that the refrigeration system afforded a sufficient cooling capacity to satisfy both the required work and the temperature level needed for reliquefaction of the boil-off gas (BOG).
본 논문은 엔진 배가스 이용 흡수식 냉동시스템에 관한 것으로, 대형 가스운반선에서 나오는 증발 가스를 흡수식 냉동시스템을 이용하여 재액화하는 시스템의 실현가능성을 증명한다. 이러한 흡수식 냉동시스템은 냉매와 흡수제로 각각 암모니아/물을 이용하며 실제 상용화된 엔진에서 나오는 배가스의 물성치를 사용하여 시물레이션을 하였다. 성능계수는 배가스의 온도가 높을수록, 엔진 로드가 커질수록 높아진다. 사례연구를 통해 LPG 및 LNG 운반선의 엔진에서 나오는 배가스로 LPG 및 LNG 증발가스를 각각 직접, 간접 방법으로 재액화가 충분히 가능하며 기존의 시스템 보다 효율이 높다는 것을 확인 하였다.
