Research Journal of Recent Sciences ______ ______________________________ ______ ____ ___ ISSN 2277 - 2502 Vol. 1( 4 ), 57 - 59 , April (201 2 ) Res.J. Recent Sci. International Science Congress Association 57 Short Communication Economic and Performance Analysis of Thermal System Dev Nikhil 1* , Attri Rajesh 1 , Mittal Vijay 2 , Kumar Sandeep 3 , Mohit 3 , Satyapal 3 and Kumar Pardeep 3 1 YMCA University of Science and Technology, Faridabad, Haryana, INDIA 2 Gateway Institute of Engineering and Technology, Sonipat, Haryana, INDIA 3 University Institute of Engineering and Technology, M.D. University Rohtak, Haryana, INDIA Available online at: www.isca.in (Received 11 th February 2012 , revised 16 th Febru a ry 2012 , accepted 23 rd February 2012 ) Abstract For the feasibility of any thermal system economic analysis is must. In the present work economic analysis of a cogeneration power plant is made for increasing the efficiency of cycle. From the literature it is being observe that for increased effici ency the factor which should be taken in to consideration are: air compressor efficiency, gas t urbine efficiency, mass flow rate of air, turbine inlet temperature, pressure loss and size of combustion chamber, LMTD for heat transfer surfaces, cycle pressure rati o and mass of steam to be produced. Mathematical model available in literature is used a nd a computer program in software MATLAB is executed for the analysis. Trend observed for the increase in cost are tabulated in the results. Keywords: GTCC, HRSG, LMTD Introduction The economy of India, a developing country, has grown rapidly in recent years, along with the electrical demand. In recent years, the use of gas turbine for power generation has increased dramatically worldwide. According to world energy forecasts, fossil fuels like coal, oil, and natural gas will continue to be the main energy sourc es for power generation in the near future in India as well as worldwide. Large - scale natural gas production in India with improved gas turbine technology has made combined cycle power plants a viable option. The thermal efficiency of gas turbine combined cycle (GTCC) power plants can reach 60% that is far more than that of conventional coal - fired steam turbine plants, which not only conserves our limited reserves but also reduces emissions and protects our lives and environment 1,2,3 . Larger gas turbines wi th higher power outputs are mainly used in combined cycle plants for heat and power cogeneration 4,5,6,7,8,9 . The main financial and cash flow concepts are as follows: Initial equity: The portion of the total investment is paid by the owner’s funds. Te remainder is paid wit borrowed money. Years for payback of equity: The time required to recoup the initial equity put up by the plant owners from the net plant cash flow. Net cash fl ow: The net amount of cash generated per year. Cumulative net cash flow: The sum of annual net cash flows for the plant over its lifetime. Operating income = Total revenues – total operating expenses. Total revenues include electricity and steam revenues . In the present work purchase equipment cost of air compressor, combustion chamber, gas turbine, air preheater and heat recovery steam generator (HRSG) is calculated on the basis of different operating parameters. Material and Methods The following cost functions for compressor, combustor, turbine, air preheater and HRSG are used for the analysis: The scheme outline d above has been numerically studied using a code developed in MATLAB. Results and Discussion With the increase of GT cycle output, the GTCC output increases even more, so the difference of GT and GTCC outputs increases. Therefore, larger gas turbines in combined cycle Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ______ ISSN 2277 - 2502 Vol. 1( 4 ), 57 - 59 , April (201 2 ) Res. J. Recent Sci. International Science Congress Association 58 power plants will experience a greater output increase than smaller gas turbines , since the electrical efficiency of the combined cycle is higher than that of a simple cycle. The efficiencies of the smaller gas turbines are not directly related to size as with the medium and large turbines where the electrical efficiency of both the G T and GTCC increases slowly with increasing output. Therefore, large gas turbines with their higher electrical efficiencies in both simple and combined cycle systems will provide better energy conservation and utilization. The total investment includes t he cost of specialized equipment, plant site infrastructure, mechanical infrastructure, buildings, etc. The specialized equipment includes the gas turbine, the steam turbine, the heat recovery boiler, the water - cooled condenser, the fuel gas compressor, th e continuous emissions monitoring system, the distributed control system, and the transmission and generating voltage equipment packages. Here purchase equipment cost of air compressor, combustion chamber, gas turbine, air preheater and heat recovery steam generator (HRSG) is calculated on the basis of different operating parameters. Cost of HRSG depends upon the Log mean temperature difference (LMTD), mass of steam produced and mass of flue gases passing through it. With increase in LMTD cost of HRSG come s down but with increase in mass of steam and flue gases cost of HRSG increases. Cost of air preheater depends upon LMTD and mass of flue gases and same trend that of HRSG is observed in it. Cost of air compressor is dependent upon the mass of air entering the compressor, compression ratio and compressor efficiency. As the value of all these three parameters increases, cost of air compressor also increases. Cost of combustion chamber (CC) depends upon the mass of air entering the combustion chamber, pressur e losses in combustion chamber and combustion chamber outlet temperature. As CC outlet temperature increases, cost of material also increases. Secondly for higher mass flow rate in CC, size of CC should be large. Both these factors increase the cost of com bustion chamber. For higher turbine inlet temperature (TIT), turbine blade material becomes costly. For higher mass flow rate of air, larger gas turbine is required. Same trend is observed for the case higher efficiency and higher turbine pressure ratio. H owever, other factors must also be taken into consideration. Table - 1 Purchase equipment cost (PEC) of HRSG LMTD 100 115 130 145 160 PEC of HRSG 426957023 426856699 426772596 426708276 426655499 Mass of steam (Kg/s) 20000 25000 30000 35000 40000 PEC of HRSG 426957023 958629405 106500940 117138940 127776940 Mass of flue gases (Kg/s) 80 85 90 95 100 PEC of HRSG 426957023 426974197 426991579 427009153 427026913 Table - 2 Purchase equipment cost of air preheater LMTD 100 110 120 130 140 150 PEC air preheater 151236 142827 135563 129207 123587 475826 Mass of flue gases (Kg/s) 80 85 90 95 100 105 PEC air preheater 151235 156765 162234 167583 172821 177955 Table - 3 Purchase equipment cost of air compressor Mass of air (Kg/s) 80 85 90 95 100 PEC compressor 946483 1005638 1064793 1123948 1183104 Compression Ratio 8 10 12 14 16 PEC compressor 946483 1308240 1692748 2102284 2520921 Compressor Efficiency 0.8 0.82 0.84 0.86 0.88 PEC compressor 946483 1183104 1577472 2366208 4732416 Research Journal of Recent Sciences ______ _ _ _______________________________ ______________ _ ______ ISSN 2277 - 2502 Vol. 1( 4 ), 57 - 59 , April (201 2 ) Res. J. Recent Sci. International Science Congress Association 59 Table - 4 Purchase equipment cost of combustion chamber Mass of air (Kg/s) 80 85 90 95 100 105 PEC of CC 111756 118740 125725 132710 139695 146679 Pressure loss in CC 0.10 0.09 0.08 0.07 0.06 0.05 PEC of CC 111756 124903 141557 163335 193033 235929 CC outlet temperature 1373 1423 1473 1523 1573 1623 PEC CC 45788 56266 82264 146679 301896 686058 Table - 5 Purchase equipment cost of gas turbine Mass of flue gases 80 85 90 95 100 105 PEC gas turbine 669271 711100 752930 794625 836448 878270 TIT 1373 1423 1473 1523 1573 1623 PEC gas turbine 669271 692601 833514 1681652 6832959 37321055 Turbine pressure ratio 8 10 12 14 16 18 PEC gas turbine 669271 740059 799585 849156 892121 930020 GT Efficiency 0.8 0.82 0.84 0.86 0.88 0.9 PEC gas turbine 669271 803125 1003906 1338542 2007813 4015626 The increase in the annual fuel consumption is almost proportional to the GTCC output. 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