High-flux thermal management at megawatt scale using a double-effect absorption/vapor-compression cascade refrigeration cycle

A robust, high-performance, cascaded double-effect absorption/vapor-compression cycle with a high temperature lift was conceptualized and analyzed for a naval ship application. A double-effect LiBr-H2O absorption cycle driven by high-temperature (>275 degrees C) exhaust heat was coupled to a subcritical CO2 vapor-compression cycle to provide low temperature refrigerant (-40 degrees C) for high-heat flux electronics applications and medium temperature refrigerant (5 degrees C) for space conditioning and other low-heat flux applications. The double-effect absorption/vapor-compression cycle outperformed the corresponding single-effect cycle, providing 74.4% higher cooling capacity for the same waste heat input; however, it required more heat exchange area. The improved performance of the double-effect configuration was much higher at lower heat rejection temperatures. A parametric study on the exhaust and heat rejection temperatures showed that the cycle exhibited high COPs over a wide range of operating conditions, indicating the robustness of the cycle. (C) 2020 Elsevier Ltd and IIR. All rights reserved.