A novel pressurized CHP system with water extraction and refrigeration

Abstract A novel Cooling, Heat, and Power (CHP) system has been proposed that features a semi-closed Brayton cycle with pressurized recuperation, integrated with a Vapor Absorption Refrigeration System (VARS). The semi-closed Brayton cycle is called the High Pressure Regenerative Turbine Engine (HPRTE). The VARS interacts with the HPRTE power cycle through heat exchange in the generator and the evaporator. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration in an amount which depends on ambient conditions. Water produced as a product of combustion is intentionally condensed in the evaporator of the VARS, which is designed to provide sufficient cooling for the inlet air to the high-pressure compressor, water extraction, and for an external cooling load. The computer model of the combined HPRTE/VARS cycle predicts that with steam blade cooling and a medium-sized engine, the cycle will have a thermal efficiency of 49% for a turbine inlet temperature of 1400 °C. This thermal efficiency is in addition to the large external cooling load generated in the combined cycle which is 13% of the net work output. In addition it also produces up to 1.4 kg of water for each kg of fuel consumed, depending upon the fuel type. When the combined HPRTE/VARS cycle is optimized for maximum thermal efficiency, the optimum occurs for a broad range of operating conditions. Details of the multivariate optimization procedure and results are presented in the paper. Previous studies have demonstrated the following attributes of the combined HPRTE/VARS cycle: attaining high part power efficiency in a compact package, threefold specific power increase over the state of the art, reduced IR signatures due to lower exhaust temperature, significant reduction of exhaust particulates and smoke, constant high-pressure compressor inlet temperature and order-of-magnitude reductions in emissions such as NOx, CO and unburned hydrocarbons. The integrated nature of this system allows overall reduction in size and weight of approximately 50% relative to conventional equipment. The combination of positive attributes makes the HPRTE combined cycle engine attractive for future mobile power applications in terms of performance as well as life cycle cost.

[1]  Nebojsa Gasparovic.  THE ADVANTAGE OF SEMI-CLOSED CYCLE GAS TURBINES FOR NAVAL SHIP PROPULSION , 1968 .

[2]  Norbert Peters,et al.  Laseroptical investigation of highly preheated combustion with strong exhaust gas recirculation , 1998 .

[3]  William E. Lear,et al.  Thermodynamic Design Point Study of a Semi-Closed Recuperated Intercooled Gas Turbine Combined With a Rankine Bottoming Cycle , 1996 .

[4]  Brian Agnew,et al.  Thermodynamic analysis of combined open-cycle-twin-shaft gas turbine (Brayton cycle) and exhaust gas operated absorption refrigeration unit , 1998 .

[5]  Alberto Traverso,et al.  WIDGET-TEMP: A Novel Web-Based Approach for Thermoeconomic Analysis and Optimization of Conventional and Innovative Cycles , 2004 .

[6]  Daniele Fiaschi,et al.  The Recuperative Auto Thermal Reforming and Recuperative Reforming Gas Turbine Power Cycles With CO2 Removal—Part II: The Recuperative Reforming Cycle , 2004 .

[7]  Gunnar Olavi Tamm,et al.  Experimental investigation of an ammonia-based combined power and cooling cycle , 2003 .

[8]  J. Wunning,et al.  Flameless oxidation to reduce thermal no-formation , 1997 .

[9]  Jack D. Mattingly,et al.  Elements of Gas Turbine Propulsion , 1996 .

[10]  Daniele Fiaschi,et al.  SCGT/CC: An innovative cycle with advanced environmental and peakload shaving features , 1997 .

[11]  Leon S. Lasdon,et al.  Design and Testing of a Generalized Reduced Gradient Code for Nonlinear Programming , 1978, TOMS.

[12]  Pedro J. Coelho,et al.  Numerical simulation of a mild combustion burner , 2001 .

[13]  S. A. Sherif,et al.  Performance of a Novel Combined Cooling and Power Gas Turbine With Water Harvesting , 2008 .

[14]  S. A. Sherif,et al.  Performance of a Novel Semi-Closed Gas Turbine Refrigeration Combined Cycle , 2003 .

[15]  S. Turns.  Introduction to Combustion , 1995, Aerothermodynamics and Jet Propulsion.

[16]  D. Himmelblau,et al.  Optimization of Chemical Processes , 1987 .

[17]  Pradeep K. Sahoo,et al.  Thermoeconomic evaluation and optimization of an aqua-ammonia vapour-absorption refrigeration system , 2006 .

[18]  S. A. Sherif,et al.  Testing and Modeling of a Semi-Closed Gas Turbine Cycle Integrated With a Vapor Absorption Refrigeration System , 2006 .

[19]  J. W. Ramsey,et al.  Thermal Environmental Engineering , 1970 .

[20]  F. J. Wang,et al.  Integration of steam injection and inlet air cooling for a gas turbine generation system , 2004 .

[21]  R. MacFarlane,et al.  System impact of H2O production and injection on a novel semi-closed cycle gas turbine , 1997 .

[22]  A. Ravindran,et al.  Engineering Optimization: Methods and Applications , 2006 .

[23]  Bruno Facchini,et al.  Comparison between two gas turbine solutions to increase combined power plant efficiency , 2000 .

[24]  S. A. Sherif,et al.  Performance of a Novel Semiclosed Gas-Turbine Refrigeration Combined Cycle , 2008 .

[25]  S. A. Sherif,et al.  Demonstration of a Novel Combined Cooling and Power Gas Turbine with Water Harvesting , 2005 .

[26]  Da-Wen Sun,et al.  Thermodynamic design data and optimum design maps for absorption refrigeration systems , 1997 .