Thermodynamic analysis and comparison of mechanical subcooling transcritical CO2 refrigeration system with expander and throttling valve

Key Words:EXERGOECONOMIC ANALYSIS; CO2 EMISSION; TEMPERATURE; CONFIGURATIONS; PERFORMANCE; EJECTOR

Abstract:High-temperature steam is a vital energy for heating, washing, drying, and other industrial processes primarily generated by special coal-fired boilers. The heat pump coupled with the steam compressor is a promising steam generation system due to its high efficiency, high heating temperature, and low pollution. In this paper, a mathematical model of a waste heat source heat pump industrial steam generation system (WHPSG) is developed. The system performance is analyzed using energy, exergy, economy, and environment methods when R245fa, R600, and R601 are selected. The results demonstrate better overall system performance at high waste heat temperature and low condensing temperature than at low waste heat or high condensing temperature. Compared to R245fa and R600, the COPsys using R601 increased by 3.4% and 3.8%, and power consumption per unit mass flow rate of steam decreased by 3.3% and 3.7. The condensing temperature influences system performance obviously, while the heat pump compressor and steam compressor account for a large percentage of exergy destruction. The system with R601 has the largest total exergy efficiency, which is higher than R245fa and R600 by about 3.0% and 3.2% respectively. The good economic and environmental benefits showed it can be used for steam generation.

Volume:330

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Translation or Not:no