An application of exergoeconomic analysis for a CHP system Ugur Yildirim, Afsin Gungor ⇑ Akdeniz University, Faculty of Engineering, Department of Mechanical Engineering, 07058 Antalya, Turkey article info Article history: Received 15 February 2011 Received in revised form 13 March 2012 Accepted 21 March 2012 Keywords: Exergy Exergoeconomics Thermodynamics Combined heat and power SPECO abstract The exergoeconomic analysis is one of the most used exergy sub-methods that combine exergy analysis with economic analysis. Based on a previous exergetic analysis of a combined heat and power (CHP) sys- tem which has a total installed electricity and steam generation capacities of 11.52 MW and 9.0 tons/h at 140 °C respectively, this study considers the thermoeconomic analysis in order to provide cost-based information and suggests possible locations for the CHP system improvement. The analysis is based on the Specific Exergy Costing (SPECO) approach and the results show that the specific unit exergy cost of electrical power produced by the CHP system is calculated as 4.48 $/GJ. The capital investment cost, the operating and maintenance costs, and the total cost of CHP system as found to be 649 $/h, 149.6 $/h and 810.2 $/h respectively. The exergoeconomic factor of the diesel engine, heat recovery exchanger, cooling tower exchanger, and cooling exchanger are 79.86%, 41.99%, 87.93%, and 55.58% respectively. The exergoeconomic factor of the compressor is 54.51% while this value is 88.3% for the tur- bine. The relative cost difference for lubrication oil cooler is calculated to be 57.60% which is the third lowest value after the charge air cooler. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Cogeneration, also known as CHP and total energy, is an effi- cient, clean and reliable approach to generating power and thermal energy from a single fuel source. Namely, cogeneration uses heat that is otherwise discarded from conventional power generation to produce thermal energy. By recycling this waste heat, cogenera- tion plants achieve a dramatic improvement in the system’s effi- ciency. In addition, the higher efficiencies of cogeneration reduce air emissions of nitrous oxides, sulfur dioxide, mercury, particulate matter and carbon dioxide, which are the leading greenhouse gases associated with climate change [1,2]. Exergy analysis has universal acceptance in the efficiency anal- ysis of any industrial process. Because of its application in a sys- tematic way, it allows the localization and account of the inefficiency degree indicating the most inefficient components in a system [3]. The exergoeconomic analysis is one of the most used exergy sub-methods that combine exergy analysis with economic analysis. The method provides a technique to evaluate the cost of inefficiencies or the cost of individual process streams, including intermediate and final products [4]. The exergoeconomic analysis aims at optimizing the overall system including both the exergetic calculations and the cost figures. The fundamentals of exergoeco- nomic analysis can be explained in four points: (i) it determines the actual cost of products or services, (ii) it provides a rational basis for pricing goods or services, (iii) it gives information on the operating decision variables, and (iv) it provides both the allo- cation and control of the expenditures [5]. A detailed literature review shows that many studies related to energetic, exergetic and thermoeconomic characteristics of cogene- ration systems are performed. Some researchers have recently made important contributions on thermodynamic analysis of cogenera- tion systems. In another study carried out by Ahmadi and Dincer [6], the exergoeconomic optimization of a dual pressure combined cycle power plant with supplementary firing was performed. They considered the cost of exergy destruction in their objective function and optimized it using a generic algorithm. Ahmadi et al. [7] per- formed the multi-objective exergy based optimization of a CHP sys- tem for both heating and cooling production. They also carried out the sensitivity analysis to see the variation of each design parameter on the system performance through energy and exergy analysis. Sa- hoo [8] carried out the exergoeconomic analysis and optimization of a cogeneration system using evolutionary programming. He consid- ered a cogeneration system which produced 50 MW of electricity and 15 kg/s of saturated steam at 2.5 bar. He optimized the unit using exergoeconomic principles and evolutionary programming. The results showed that for the optimum case in the exergoeconom- ic analysis the cost of electricity and production cost are 9.9% lower in comparison with the base case. Yet another study of Ahmadi et al. [9] analyzed a combined cycle power plant with a supplementary firing system using energy and exergy analysis methods while they utilized a generic algorithm type optimization method. Ahmadi et al. [10,7] undertook a comprehensive exergy, exergoeconomic and 0142-0615/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijepes.2012.03.040 ⇑ Corresponding author. E-mail address: [email protected](A. Gungor). Electrical Power and Energy Systems 42 (2012) 250–256 Contents lists available at SciVerse ScienceDirect Electrical Power and Energy Systems journal homepage: www.elsevier.com/locate/ijepes
Transcript
Electrical Power and Energy Systems 42 (2012) 250–256
Contents lists available at SciVerse ScienceDirect
Electrical Power and Energy Systems
journal homepage: www.elsevier .com/locate / i jepes
An application of exergoeconomic analysis for a CHP system
Ugur Yildirim, Afsin Gungor ⇑Akdeniz University, Faculty of Engineering, Department of Mechanical Engineering, 07058 Antalya, Turkey
a r t i c l e i n f o a b s t r a c t
Article history:Received 15 February 2011Received in revised form 13 March 2012Accepted 21 March 2012
Keywords:ExergyExergoeconomicsThermodynamicsCombined heat and powerSPECO
0142-0615/$ - see front matter � 2012 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.ijepes.2012.03.040
The exergoeconomic analysis is one of the most used exergy sub-methods that combine exergy analysiswith economic analysis. Based on a previous exergetic analysis of a combined heat and power (CHP) sys-tem which has a total installed electricity and steam generation capacities of 11.52 MW and 9.0 tons/h at140 �C respectively, this study considers the thermoeconomic analysis in order to provide cost-basedinformation and suggests possible locations for the CHP system improvement. The analysis is based onthe Specific Exergy Costing (SPECO) approach and the results show that the specific unit exergy cost ofelectrical power produced by the CHP system is calculated as 4.48 $/GJ. The capital investmentcost, the operating and maintenance costs, and the total cost of CHP system as found to be 649 $/h,149.6 $/h and 810.2 $/h respectively. The exergoeconomic factor of the diesel engine, heat recoveryexchanger, cooling tower exchanger, and cooling exchanger are 79.86%, 41.99%, 87.93%, and 55.58%respectively. The exergoeconomic factor of the compressor is 54.51% while this value is 88.3% for the tur-bine. The relative cost difference for lubrication oil cooler is calculated to be 57.60% which is the thirdlowest value after the charge air cooler.
� 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Cogeneration, also known as CHP and total energy, is an effi-cient, clean and reliable approach to generating power and thermalenergy from a single fuel source. Namely, cogeneration uses heatthat is otherwise discarded from conventional power generationto produce thermal energy. By recycling this waste heat, cogenera-tion plants achieve a dramatic improvement in the system’s effi-ciency. In addition, the higher efficiencies of cogeneration reduceair emissions of nitrous oxides, sulfur dioxide, mercury, particulatematter and carbon dioxide, which are the leading greenhouse gasesassociated with climate change [1,2].
Exergy analysis has universal acceptance in the efficiency anal-ysis of any industrial process. Because of its application in a sys-tematic way, it allows the localization and account of theinefficiency degree indicating the most inefficient components ina system [3]. The exergoeconomic analysis is one of the most usedexergy sub-methods that combine exergy analysis with economicanalysis. The method provides a technique to evaluate the cost ofinefficiencies or the cost of individual process streams, includingintermediate and final products [4]. The exergoeconomic analysisaims at optimizing the overall system including both the exergeticcalculations and the cost figures. The fundamentals of exergoeco-nomic analysis can be explained in four points: (i) it determinesthe actual cost of products or services, (ii) it provides a rational
ll rights reserved.
gor).
basis for pricing goods or services, (iii) it gives information onthe operating decision variables, and (iv) it provides both the allo-cation and control of the expenditures [5].
A detailed literature review shows that many studies related toenergetic, exergetic and thermoeconomic characteristics of cogene-ration systems are performed. Some researchers have recently madeimportant contributions on thermodynamic analysis of cogenera-tion systems. In another study carried out by Ahmadi and Dincer[6], the exergoeconomic optimization of a dual pressure combinedcycle power plant with supplementary firing was performed. Theyconsidered the cost of exergy destruction in their objective functionand optimized it using a generic algorithm. Ahmadi et al. [7] per-formed the multi-objective exergy based optimization of a CHP sys-tem for both heating and cooling production. They also carried outthe sensitivity analysis to see the variation of each design parameteron the system performance through energy and exergy analysis. Sa-hoo [8] carried out the exergoeconomic analysis and optimization ofa cogeneration system using evolutionary programming. He consid-ered a cogeneration system which produced 50 MW of electricityand 15 kg/s of saturated steam at 2.5 bar. He optimized the unitusing exergoeconomic principles and evolutionary programming.The results showed that for the optimum case in the exergoeconom-ic analysis the cost of electricity and production cost are 9.9% lowerin comparison with the base case. Yet another study of Ahmadi et al.[9] analyzed a combined cycle power plant with a supplementaryfiring system using energy and exergy analysis methods while theyutilized a generic algorithm type optimization method. Ahmadi et al.[10,7] undertook a comprehensive exergy, exergoeconomic and
c cost per unit of exergy ($/GJ)_C cost rate associated with exergy ($/h)Cm payment in a year ($) w_Ex exergy rate (kW)_Eheat rate of exergy transfer by heat (kW)h enthalpy (kJ/kg)_m mass flow rate (kg/s)
Pm present value of the payment ($)_Q rate of heat transfer (kW)s entropy (kJ/kg K)T temperature (�C)T0 environment temperature (�C)w specific work (kJ/kg)_W power_Z cost rate associated with the sum of capital investment
and O&M ($/h)_ZCL cost rate associated with capital investment ($/h)_ZOM cost rate associated with O&M ($/h)
Greek Lettersa inlet exergy depletion ratio (%)b fuel exergy depletion ratio (%)
g exergy (second law) efficiency (%)w specific flow exergy (kJ/kg)s total annual operating hours of system at full load (h)
Subscriptse exiteff effectiveL levelizedk any componenti inletin inputout outputq heatw work
AbbreviationsCRF capital recovery factorPEC purchased equipment costCC carrying chargesOMC operating and maintenance costsEXC expenditure costs
U. Yildirim, A. Gungor / Electrical Power and Energy Systems 42 (2012) 250–256 251
environmental impact analysis and optimization of several com-bined cycle power plants.
This study deals with exergoeconomic analysis of a CHP systembased on a previous exergetic analysis of a CHP system which has atotal installed electricity and steam generation capacities of11.52 MW and 9.0 tons/h at 140 �C respectively [1]. SPECO ap-proach is used in this analysis which is based on specific exergies,and costs per exergy unit, exergetic efficiencies, and the auxiliarycosting equations for components of thermal systems [11]. Themain objectives of this study are to (a) derive exergoeconomic rela-tions, (b) evaluate the exergoeconomic performance of each com-ponent and the CHP system by using actual cost data, (c)improve the overall efficiency of the system by determining themain loss locations thus providing optimization of process, (d) con-duct a parametric study of the effect of fuel cost rate and poweroutput of the CHP.
2. System description
The CHP system investigated in the present study has two dieselengines. Each diesel engine set in the plant produces 5.76 MWelectrical power and the steam capacity of each diesel engine is4.5 tons/h. The steam pressure is 6 bars and the temperature is165 �C. The hot water capacity of the system is 140 ton/h and thepressure is 7 bars and the temperature of water is 102 �C. Heavyfuel oil number 6 is used as a fuel for engines. The annual fuel con-sumption is nearly 20,000 tons at designed operating conditions.More details of the system can be found in the literature [2]. Theschematic diagram of this plant is shown in Fig. 1. Mass flow rate,temperature, pressure, enthalpy, entropy, specific exergy and exer-gy rate for the CHP system streams are also given in Table 1.
3. Exergoeconomic analysis
The exergoeconomic analysis is a method that combines exergyanalysis with economic analysis. This study deals with exergoeco-nomic analysis of a CHP system based on a previous exergeticanalysis of a combined heat and power (CHP) system which has atotal installed electricity and steam generation capacities of
11.52 MW and 9.0 tons/h at 140 �C respectively [1]. In the previousstudy, energy and exergy analyses of an actual diesel enginepowered cogeneration plant was carried out by analyzing the com-ponents of the system separately. Both the performance characteris-tics of the internal combustion engine unit and the supportingcomponents in the plant was evaluated. The exergetic efficienciesof the system components are shown in Fig. 2. The rate of exergydestructions of the components of the plant as compared with thefuel exergy input are shown in Fig. 3.
The inlet exergy rate, the outlet exergy rate, the exergy con-sumption, the inlet exergy depletion ratio, the fuel depletion ratio,the exergetic improvement potential and the ratio of exergy con-sumption to the capital cost are calculated for each componentand CHP system and are given in Table 2. In the present study,the inlet exergy depletion ratio is the ratio of the exergy consump-tion rate of kth component to the exergy rates input of the CHPsystem and is calculated from
ak ¼_ExC
k_Exin;CHP
ð1Þ
The fuel depletion ratio is defined as the ratio of the exergyconsumption of kth component to the fuel exergy rate input ofthe CHP [12] an the system is given as follows:
bk ¼_ExC
k_Exf
ð2Þ
Van Gool [13] stated that maximum improvement in the exergyefficiency for a process or system can be achieved when the exergyloss is minimized. Consequently, he suggested that it is useful toemploy the concept of an exergetic ‘improvement potential’ whenanalyzing different processes. The exergetic improvement poten-tial can be written as follows [13–15]
_ExIPk ¼ ð1� gÞ _ExCk ð3Þ
For identifying the effect of exergy consumption of kth compo-nent of the CHP system to capital cost, it has been suggested by Ro-sen and Dincer [16] a new parameter called ‘‘the ratio of exergyconsumption rate to capital investment cost’’ given as follows
Fig. 1. Schematic flow diagram of the diesel engine based cogeneration system.
252 U. Yildirim, A. Gungor / Electrical Power and Energy Systems 42 (2012) 250–256
Rxk ¼_ExC
k
CACCHPð4Þ
In the economic analysis of the cogeneration systems, theannual values of carrying charges, fuel costs, raw water costs,and operating and maintenance (O&M) expenses supplied to theoverall system are the necessary input data. However, thesecost components may vary significantly within the economiclife. Therefore, levelized annual values must be used in theeconomic analysis of the overall system. The levelized cost is givenby [17]
A ¼ CRFXn
m¼1
Pm ¼ið1þ iÞn
ð1þ iÞn � 1
Xn
m¼1
Pm ð5Þ
where CRF is capital recovery factor which depends on the interestrate as well as estimated equipment lifetime. CRF is determinedusing the relation ið1þ iÞn=ðð1þ iÞn � 1Þ, in which i, is the interestrate and n is the total operating period of the system in years[18]. It is taken as the average general interest rate within the plantentire economic life, which is 5% in US dollars. Present value of thepayment, Pm is calculated as follows;
Pm ¼ Cm1
ð1þ iÞmð6Þ
The cost ratio associated with the capital and O&M expenses forthe kth component of the cogeneration power plant is [17]
_Zk ¼CCL þ OMCL
s
� �PECkX
k
PECk
ð7Þ
The first term in the nominator of the right hand side in Eq. (7)gives _ZOM
k , and the second term gives _ZCLk : The levelized cost rate of
the expenditure (fuel, raw water) supplied to the overall system is
_CEX ¼EXCL
sð8Þ
In Table 3, the levelized cost values of the carrying charges andexpenditures of the CHP system are given. The cost data for carry-ing charges, fuel, raw water, O&M are obtained from the company.It is taken as average general inflation rate within the entire eco-nomic life, which is 6% in US dollars. The average annual nominaldiscount rate is estimated as 12% in this study. The average capac-ity factor for the cogeneration system is considered as 85% whichmeans that the system will operate at 7446 h out of the total avail-able 8760 h per year. Levelized cost rate of fuel is calculated to be785.2 $/h and that of the raw water to be 1.78 $/h.
Since the plant studied in this paper produces steam and hotwater as ‘‘byproducts’’ and it is small fraction of the electrical out-put, we consider only electrical output as the product. Thus its unitcost (MPUC) can be calculated from the annual total revenuerequirement (TRR), the annual total value of the byproducts (BPVs)produced in the same plant, and the main product quantity (MPQ)[17]
Table 1Plant data, thermodynamic properties, and exergies in the plant with respect to state points in Fig. 1. Values are for one diesel engine only.
StateNo
Flow identification Mass flow rate m⁄ (kg/s) Temperature T(�C)
Pressure P(kPa)
Enthalpy h (kJ/kg)
Entropy s (kJ/kgK)
Specific exergy W (kj/kg)
Exergy rate Ex⁄ (kW)
0 Air – 30 100 303.5 5.712 0.0 –0 Water – 30 100 125.1 0.434 0.0 –0 Fuel oil – 30 100 – – 0.0 –0 Lub-oil – 30 100 – – 0.0 –1 Inlet fuel 0.318 125 640 203.18 0.579 32.58 10.362 Inlet air to compressor 11.00 30 100 304.66 5.712 0.00 0.003 Charge air after compressor 11.00 225 300 500.64 5.897 159.23 1751.584 Charge air to engine 11.00 55 300 329.79 5.475 32.24 354.645 Exhaust gas inlet turbine 11.31 520 240 797.11 6.459 470.04 5316.156 Exhaust gas outlet turbine 11.31 330 2.5 606.16 7.461 249.03 2816.537 Shaft (30,000 rpm) – – – – –8 Exhaust gas to atmosphere 11.31 210 2.5 487.55 2.5795 55.51 627.819 Steam for factory 12.5 165 600 2771.03 6.7934 92.86 1160.75
10 Feed and condensate water 12.5 102 700 427.94 1.3289 14.68 183.5011 Inlet charge air cooler water 31.67 35 146.79 0.5047 5.76 182.4212 Inlet charge air cooler water 31.67 35 260 146.79 0.5047 5.76 182.4213 Outlet charge air cooler water 31.67 40 260 167.68 0.5720 8.31 263.1714 Inlet lube oil cooler 38.88 75 420 91.166 0.2804 5.55 215.7815 Outlet lube oil cooler 38.88 65 420 69.967 0.2184 1.27 49.3716 Lube oil to inlet diesel engine 38.88 65 420 69.967 0.2184 1.27 49.3717 Inlet charge air water to cooling tower exchanger 31.66 50 260 209.47 0.7034 14.31 453.0518 Inlet cooling tower exchanger from cooling tower 31.94 30 300 125.93 0.4364 3.45 110.1919 Inlet low temperature water 31.94 30 300 125.93 0.4364 3.45 110.1920 Outlet low temperature water 31.94 40 300 167.71 0.5720 8.21 262.2221 Outlet cooling tower 31.66 25 300 105.04 0.3669 1.52 48.1222 Inlet high temperature water 31.66 25 300 105.04 0.3669 1.52 48.1223 Outlet high temperature water 31.66 40 300 167.71 0.5720 8.21 259.9324 Engine cooling water inlet heat recovery exchanger 20.00 75 420 314.24 1.0152 33.98 679.6025 Water from factory inlet heat recovery exchanger 38.88 70 600 293.44 0.9544 29.23 1136.4626 Water for factory outlet heat recovery exchanger 38.88 90 550 377.28 1.1922 48.31 1878.3027 Engine cooling water outlet heat recovery
Table 5The unit exergy costs of fuels and products, relative exergetic cost difference, exergoeconomic factor, cost rate of exergy destruction, and total investment cost rate for the plantcomponents.
Component Cf ;k ð$=GJÞ Cp;k ð$=GJÞ r (%) f (%) _DD_ZT
Thus the levelized unit cost of electricity for the 25-year periodcan be calculated from Eq. (9)
MPUCL ¼8:906� 106 � 0:013� 106
85:78� 106 ¼ 0:1037 $=kWh ð11Þ
This value represents the levelized cost for a 25 year-periodassumption average annual nominal escalation rates for the fuelcost and the O&M expenses of 4.5% for the entire economic lifeof the CHP system. Monetary costs express the economic effectof inefficiencies and are used to improve the cost effectiveness ofproduction processes. Assessing the cost of the flow streams andprocesses in a plant helps to understand the process of cost forma-tion, from the input resources to final products [17,19].
The exergoecomic analysis is based on SPECO approach. Thismethod is based on specific exergies, and costs per exergy unit,exergetic efficiencies, and the auxiliary costing equations forcomponents of thermal systems. The method consists of three
main steps (i) identification of exergy streams, (ii) definition of fueland product for each component of thermal system and (iii) alloca-tion of cost equations.
_Ci ¼ ci_Ei ¼ c1ð _miwiÞ ð12Þ
_Ce ¼ ce_Ee ¼ ceð _meweÞ ð13Þ
_Cw ¼ cw_W ð14Þ
_Cq ¼ cq_Eq ð15Þ
Eqs. (12)–(15) give exergy transfers by the entering and exitingstreams of matter and by power and heat transfer rates.
A cost balance applied to the kth system components showsthat the sum of cost rates associated with all existing exergystream equals the sum of cost rates of all entering exergy streamsplus the appropriate charges due to capital investment and operat-ing and maintenance expenses. The sum of the last two terms isdenoted by _Zk. Eq. (16) gives the general cost rate balance for acomponent receiving heat transfer and generating power [19]:X
e
ðce_EeÞk þ cw;k
_Wk ¼ cq;k_Eq;k þ
Xi
ðci_EiÞk þ _Zk ð16Þ
256 U. Yildirim, A. Gungor / Electrical Power and Energy Systems 42 (2012) 250–256
More details of the exergoeconomic analysis, cost balance equa-tions, and exergoeconomic factors are completely discussed inRefs. [8,20,21]. Thoroughly, several methods have been suggestedto express the purchase cost of equipment in terms of designparameters in Eq. (16) [7,21,22]. In this study, we use the costfunctions as suggested by Roosen et al. [23]. The exergoeconomicfactor fk is defined for a k component as
fk ¼_Zk
_Zk þ cf ;k_ExC
k
ð17Þ
where cf,k is the unit exergetic cost of the fuel of any k componentand _ExC
k is the corresponding exergy consumption of the same com-ponent. The relative cost difference rk is defined as
rk ¼cp;k � cf ;k
cf ;kð18Þ
where cp,k is the unit exergy cost of the product of any k component.The cost rate of exergy consumption is defined as [12]
_DD;k ¼ cf ;k_ExC
k ð19Þ
More detailed information about the main components exergo-economic cost balance is available [7].
4. Results and discussion
The purchased equipment cost, the hourly levelized costs capi-tal investment, the operating and maintenance costs, and the totalcost of components of the plant are given in Table 4 (more detailsare given in the literature [7,9,11]) and the exergetic cost parame-ters of the plant components are given in Table 5. The results ofthis study could be summarized as follows:
(i) The net electrical power output of the plant is 11.52 MW andthe specific unit exergetic cost of the power produced by the plantis 4.48 $/GJ. The corresponding value of this cost for the diesel en-gine is 1.24 $/GJ. (ii) The diesel engine is the most exergy destruc-tive component of the plant due to its inherent nature. Theexergoeconomic factor of the diesel engine is calculated to be79.86%, a decrease of the exergy destruction could be cost effectiveeven if this would increase the investment cost for the diesel en-gine. (iii) The capital investment cost, the operating and mainte-nance costs, and the total cost of CHP system as found to be649 $/h, 149.6 $/h and 810.2 $/h respectively. (iv) The exergoeco-nomic factor of heat recovery exchanger, cooling tower exchanger,and cooling exchanger are 41.99%, 87.93%, and 55.58% respectively.(v) The exergy unit cost is highest for the pump work since all exer-gy available at the exit of the pump is supplied by mechanicalpower which is the most expensive fuel in the system. The exergo-economic factor is rather high (90.73%) due to the higher initialcost relative to cost rate of exergy destruction. (vi) The exergoeco-nomic factor of charge air cooler is 28.21. This is the lowest valueamong the plant components which is due to the high value ofexergetic destruction cost rate compared with low total invest-ment cost. (vii) The relative cost difference for lubrication oil cooleris determined to be 57.60% which is the third lowest value. It alsohas a low destruction cost rate of 3.66 $/h. It may be suggested thata decrease in the investment cost may improve the cost effective-ness of the system. (viii) The exergoeconomic factor of thecompressor is 54.51% while this value is 88.30% for the turbine.
5. Conclusions
Developing techniques for designing efficient and cost-effectiveenergy systems is one of the foremost challenges energy engineers
face. Based on a previous exergetic analysis of a CHP system, thisstudy presents that exergoeconomic analysis may provide furtherinformation than exergy analysis, and the results from exergoe-comic analysis provide cost-based information, suggesting possiblelocations for the CHP system improvement. The exergoeconomicperformance of each component and the CHP system is evaluatedby using actual cost data. The results of this study has been alsoimproved the overall efficiency of the system by determining themain loss locations thus providing optimization of process andconducted a parametric study of the effect of fuel cost rate andpower output of the CHP. The plant owner may maintain an opin-ion for future improvements by decreasing the unit exergy cost ofthe investigated plants and checking the exergy consumption loca-tions within the plants. The exergetic performance results indicatethat the engine is by far the most exergy destructive equipment inthe plant.
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