Performance assessment of a waste-heat driven CO2-based combined power and refrigeration cycle for dual-temperature refrigerated truck application. (1st December 2021)

• Record Type: Journal Article
• Authors: Pan, Mingzhang; Zhu, Yan; Liang, Youcai; Lu, Fulu; Zhi, Ruiping; Xiao, Gang
• Is Part Of: Energy conversion and management. Volume 249(2021)
• Publication Date: 2021-12-01
• Subjects: Refrigerated truck -- Combined power and refrigeration cycle -- Dual-temperature refrigeration cycle -- Ejector -- Carbon dioxide -- Waste heat recovery; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2021.114863
• Languages: English
• ISSNs: 0196-8904

Abstract

Abstract: Huge thermal losses through the exhaust system of the refrigerated truck offer an opportunity for lowering fuel consumption by using waste heat recovery system. To meet the demand of mixed load of refrigerated truck, a basic cycle integrating the supercritical CO2 cycle and dual-temperature refrigeration cycle (BSRC) is proposed and evaluated from the thermodynamic and economic perspective. Besides, a two-phase ejector is introduced into the BSRC to improve cycle performance (defined as SRCE). The proposed cycles can conveniently change operation modes in response to different forms of energy demand, including combined power generation, refrigeration and freezing (mode 1), refrigeration and freezing (mode 2), power generation (mode 3). Detailed parametric analysis and performance comparison between the BSRC and the SRCE are conducted. Thereafter, multi-objective optimization is employed to obtain the optimal operating condition. Comparison results show that the SRCE presents superiority than BSRC owing to pressure lift provided by the ejector. Besides, the advantage of employing ejector is more pronounced under mode 2 than under mode 1. The SRCE can provide an extra power of 28.19 kW under mode 1 when the basic need for freezing and refrigeration (1.635 kW) is satisfied, accounting for 11.23% of the engine power output. And the exergy efficiency and sum unit cost of product of the SRCE are 57.186% and 13.78 $/GJ, respectively. Compared with the BSRC, the exergy efficiency and sum unit cost of product of the SRCE under mode 2 are respectively increased by 15.92% and decreased by 14.85%. While under mode 3, the SRCE can be regarded as a typical regenerative SCO2 cycle, which can provide considerable net power output of 28.362 kW.