An Innovative Polygeneration System Integrating Compressed Air Energy Storage (CAES) and Multi-effect Desalination for Efficient LNG Cold Energy Utilization

Abstract

Liquefied natural gas (LNG) contains a huge amount of cold energy, generally wasted during the regasification process. With the increasing penetration of renewable energy in the grid, the power generation profile does not match well with that of power demand, which causes power shortage during peak hours and surplus power during off-peak hours. Under this circumstance, a hybrid energy system integrating compressed air energy storage (CAES) system with LNG cold energy utilization process is proposed to address these issues. The integrated system consists of an organic Rankine cycle (ORC), a gas turbine, a multiple effect desalination unit, a CAES system, and a domestic cooling unit. A comprehensive analysis is carried out to assess the system’s economic and thermodynamic performance. The study presents a parametric study to illustrate the impacts of critical parameters on the system performance. The energy efficiency of the integrated system is boosted significantly since the ORC can utilize the LNG cold energy and compression waste heat from the CAES system simultaneously. The proposed system can produce 29.8 MWh of electrical energy and 2.6 kg/s fresh water during peak hours. Also, results show that the value of CO2 emission, exergetic round trip efficiency, and cost rate are 0.267 kg/kWh, 45.9 %, and 448.6 $/h.