Introducing a novel integrated cogeneration system of power and cooling using stored liquefied natural gas as a cryogenic energy storage system

Abstract

Nowadays, it is inevitable to use energy storage systems for peak shaving and load leveling purposes. In the present study, a new integrated structure of power generation and refrigeration is developed for the use and recovery of the stored liquid natural gas energy as a cryogenic energy storage system. Kalina power cycle, molten carbonate fuel cell, carbon dioxide power cycle, and absorption-compression refrigeration system using solar energy are employed to achieve this goal. This new integrated structure generates 161,287 kW power, 1964 kW refrigeration at 266 K through LNG recovery with 4.066 kg/s mass flow rate and 8464 kW refrigeration at 218.5 K. Electrical, thermal and exergy efficiencies of the whole system are 57.92%, 61.66%, and 68.21%, respectively. In the present study, considering the efficiency of the LNG production and storage sector at the off-peak time as well as its cryogenic energy recovery sector at the on-peak time, round-trip efficiency of the proposed cryogenic storage system is calculated as 66.29%. Via the parametric study on major system parameters such as Tu101 and Tu102 turbines inlet pressures, Tu201 turbine outlet temperature, etc., the performance of the system in various conditions is evaluated. Important results of the parametric study include an increase in the system total thermal efficiency up to 70.03% by reducing the outlet temperature of the Tu201 turbine to 880 K.