Indian Journal of Science and Technology
Year: 2017, Volume: 10, Issue: 28, Pages: 1-9
Anjan Kumar Sahu1 , Neeraj Agrawal2 * and Prasant Nanda3
1Department of Mechanical Engineering, Aalim Muhammed Salegh College of Engineering, Chennai − 600055, Tamil Nadu, India; [email protected] 2Department of Mechanical Engineering, Dr. Babasaheb Ambedkar Technological University, Lonere, Raigad − 402103, Maharashtra, India; [email protected] 3Department of Mechanical Engineering, VSSUT, Burla −768018, Odisha, India; [email protected]
*Author For Correspondence
Department of Mechanical Engineering, Dr. Babasaheb Ambedkar Technological University, Lonere, Raigad − 402103, Maharashtra, India; [email protected]
Objective: Researchers have started proposing the use of natural refrigerants like CO2 and N2 O in place of CFCs and HCFCs. The cycles using these refrigerants operate in transcritical region. Thus, there is a scope of combined power generation with cooling. This has been analyzed in this work. Methods: The energetic and exergetic analysis are carried out on transcritical CO2 and N2 O combined power and refrigeration cycles. The equations thus generated for COP and exergetic efficiency are studied for their behavioral dependence on various influencing parameters like evaporator temperature, gas cooler outlet temperature, gas heater pressure and turbine inlet temperature. In the entire analysis the standard property code is used in the program for evaluation of properties. Findings: For a comparison, the Grassmann diagrams for both CO2 based and N2 O based combined power and refrigeration cycles have been presented at a given operating condition. It is noticed that the performances of transcritical N2 O combined power cycle is better than transcritical CO2 combined power cycle as it has higher COP and exergetic efficiency under all operating conditions. It is also found that there exists an optimum evaporator temperature at which the exergetic efficiency attains maximum value. Specific exergy loss is found more for throttle valve and compressor. Application: The natural gas based combined power and refrigeration cycle can be used in large applications like cooling and heating in ships or large ice plants etc.
Keywords: Exergy, Grassmann Diagram, Power- Refrigeration Cycle, Transcritical, CO2 , N2 O
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