Net Heat Rate Research Articles

Development of solver with user interface for surface radiative exchange based on OpenFOAM platform

Surface radiative exchange is widely used in the fields related to industrial and environment. Accurate and rapid calculation of the surface radiant heat flux can predict and prevent accidents. In this study, a solver for surface radiative exchange based on the OpenFOAM platform is developed. The solver’s accuracy can be verified by calculating the net heat rate of the cubic cavity and the triangular-prism geometries. The solarLoad radiation model is used to study the variation of heat flux with respect to the solar incidence angle for a satellite in orbit and a human standing in a room with a window. Finally, a Graphical User Interface (GUI) based on the PyQt5 for this solver is developed to simplify the operation process and make the solver user-friendly.

Performance Assessment of Single Flash PLTP LMB 1 After First Year Inspection Using ASME PTC 46:1996 Method

PLTP LMB 1 performs a First-Year Inspection after operating for one year to inspect and repair equipment after the operation. After these activities, a performance test needs to be carried out to determine the effectiveness and success of these activities. ASME PTC 46: 1996 is a widely-used standard for analyzing the performance test of thermal power plant systems, which includes plant heat rate, power output, specific mass consumption, and more. The purpose of the testing is to evaluate the results of system improvements. Calculation and comparative analysis are performed to determine the system's condition during warranty, commissioning, and testing, as well as after one year of operation and post-first year inspection. After testing, the thermal performance of PLTP LMB 1 was obtained as follows: The corrected net plant heat rate (NPRH) was 18923 kJ/kWh, the corrected net power output was 56,417 MW, and the net specific mass consumption (NSMC) was 6,881 tons/MW. Based on the data guarantee, the thermal performance value of PLTP LMB1 is still below the required value, so it can be concluded that the thermal performance value of PLTP LMB1 is in good condition. The isentropic turbine efficiency value decreased by 2.1% from its design value of 85% to 82.9%, which was caused by suboptimal heat energy absorption by the turbine above the design pressure of 5 bar.

Combustion optimization of a coal-fired power plant boiler using artificial intelligence neural networks

This study establishes detailed neural network modeling procedures for the combustion optimization of a power generation unit, equipped with a Selective Catalytic Reduction (SCR) system. In particular, artificial intelligence neural networks were applied due to its capability in treating large pools of data of great nonlinearity. The objective of this study was to reduce nitrogen oxide (NOx) emissions in the stack gas, lower the cost of emissions compliance and minimize the net unit heat rate at this power generation unit at full-load conditions. These procedures include building a database with real coal power plant operating data, modeling the database and using the genetic algorithm to optimize the operating conditions. The operation is optimized with respect to the steam temperature, selective catalyst reactor, and separated over-fire air conditions. Verifications of the results demonstrated that by carrying out the reported study, the pollutant concentrations of the boiler are significantly decreased and the catalyst layer is effectively preserved, while the operation can be maintained stable near the full-load condition. It was found that the average ammonia (NH3) flow to the SCR under optimized conditions was 229 kg/h, while the average NH3 flow under non-optimal operational conditions was 260 kg/h, resulting in a reduction in NH3 consumption of approximately 12 % from the non-optimized operational condition. In the meantime, the SCR inlet (boiler exit) NOx was reduced from 523 mg/Nm3 (non-optimized operational condition) to 444 mg/Nm3 (optimized operational condition), which represent about 15 % reduction. Based on the experience with SCR from manufactures and operators, the SCR catalyst life expectancy has a direct relationship with the SCR inlet NOx concentration and NH3 injection rate. The lower the NOx concentration at the SCR inlet and the less the NH3 injection rate, the longer of the SCR catalyst life will be. Thus, it is expected that the SCR catalyst layer replacement frequency could be reduced by 10 to 20 % over the normal catalyst replacement cycle, while meeting the same environmental NOx emissions limit. Additionally, a Delta Heat Rate was also calculated using best available data from the optimized operational conditions, including boiler load, boiler excess oxygen (O2), fly ash unburned carbon and attemperation flow. Results were compared with the average Delta Heat Rate calculated from baseline tests. It was found that the average Delta Heat Rate from baseline tests are −60 kJ/kWh, while the delta heat rate from the optimized operation condition hours is −118 kJ/kWh. This represents about 0.57 % improvement on unit heat rate from the baseline average.

Determination of Optimum Point of Composition of Fuel Calories in Producing electrical Energy in Coal Fired Power Plant

Coal-fired power plant (CFPP) is a type of power plant that is widely used for 35,000 MW electricity projects in Indonesia. CFPP must adjust to its operating strategies with the availability of abundant low-rank coal, and it will affect CFPP performance. This study aims to determine the optimum heating value of fuels, the trend of net plant heat rate (NPHR), the cost of electricity production (component C), and the optimum point of the CFPP operation. The data used is from CFPP operations. First, data is analyzed by descriptive statistics and formed into a regression model. The next step is to estimate the parameters of the population data. The regression model obtained was then carried out the goodness of fit test and residual analysis. Then, the variable’s values are changed to the Z-score and plotted in the regression model. The model interpretation is carried out and conclusions can be obtained to find out the optimum point. The conclusion of this study is the optimum point of generating electricity in CFPP can be achieved by using coal calorific values of 4,450 kCal/kg, NPHR of 2,683.6 kCal/kWh, and COE (component C) of Rp 436.5/kWh when using coal at a price of 732.2/kg and Net Power of 279 MW.

A Study of Reducing Waste Heat Rejected By Condenser Using Thermoelectric Heat Pumps to Decrease Net Plant Heat Rate of Coal Fired Power Plant

Paiton 1-2 subcritical coal-fired power plant applied coal switching program in order to can compete at Jawa-Bali electrical system. The calorific value of coal consumed is switched from 5200 kcal/kg to 4500 kcal/kg. As the result, it increases the net plant heat rate (NPHR) as well as the coal flow and produce more CO2 emissions. Increasing final feed water temperature can reduce NPHR because less heat needed to produce steam. One of promising method to increase feed water temperature is reusing wasted energy being rejected to environment through condenser. There is opportunity to reuse this waste heat by use of thermoelectric heat pumps (THPs). THPs convert electrical energy into thermal energy using Peltier effect. It can capture the heat released by condensation process and reused for increasing the feed water temperature, which can increase the cycle efficiency. Furthermore, it will reduce coal flow, decrease NPHR and aid the reduction of CO2 emissions. To maximize the energy recovery, a number of heat pumps can be used in series. This paper focused on finding the optimum number of heat pumps array. The expected feed water temperature rise gained from THPs arrangement is 19.81°C and potentially will contribute to 0.66% reduction on NPHR.

Analisa Keseimbangan Energi PLTU Takalar (Punagaya) Unit 2 Berdasarkan Perubahan Beban

This study aims to calculate the efficiency and heat rate of the unit 2 PLTU Takalar (Punagaya) system with the energy balance calculation method, calculate the NPHR value of PLTU Takalar (Punagaya) unit 2 when the unit is operating, and also to determine the energy loss from the conversion energy results at PLTU Takalar (Punagaya) unit 2 when the unit operates. The PLTU's Net Plant Heat Rate (NPHR) value is a very important role as an indicator of the performance of a steam power plant. The real-time NPHR value calculation using the energy balance method can be used as an evaluation material to control the operation pattern of the generator in order to obtain optimal operation. The method used in this research is to collect direct and indirect data to calculate the energy balance and NPHR of PLTU Takalar (Punagaya) unit 2 during the reliability run period. The calculations carried out include the calculation of the energy balance in the boiler, the energy balance in the steam cycle, the balance of electrical energy, the efficiency of the PLTU and NPHR systems. Based on the results of calculations that have been carried out the efficiency and NPHR of PLTU Takalar (Punagaya) unit 2 is the best during the reliability run of 32.76% and 2801.93 kcal / kWh at full load conditions with an energy loss value of 220.60 MW. The performance of PLTU Takalar (Punagaya) unit 2 during the reliability run is very good where the unit operates continuously and the NPHR value when full load fulfills the contract warranty and the maximum operating target.Â

Inlet Guide Vane Tracking Effectiveness at Various Compressor Efficiency of Gas Turbine

The baseload operating patterns in Java-Bali’s system are imposed on coal-fired power plants, the combined cycle power plant (CCPP) is used as a spinning reserve so that the CCPP operates with a small load factor (partial load) to support system reliability. This operation results in a high plant heat rate for the CCPP since it operates more often at minimum loads. To improve the heat rate of CCPP at partial load, inlet guide vane tracking (IGVT) is performed. IGVT alters the opening position of inlet guide vane (IGV) in the partial load operation. The effect of IGVT application in CCPP is analysed with several operating parameters, such as fuel usage, turbine exhaust temperature (TET), the total load generated by the CCPP, and the total of net plant heat rate (NPHR) after IGVT application. The variation on IGV leads TET to increase. A higher TET affects the heat recovery steam generator (HRSG) and causes the load generated by the steam turbine to become larger compared to the load before performing IGVT application. The results show that the combined cycle heat rate drops to 24 kCal/kWh and thus improving the efficiency of the CCPP, up to 1.5% in partial load operation model.

Study of Debris Filter Valve Opening Angle Adjustment for NPHR Improvement in Kaltim Teluk CFPP

Many things can affect the Net Plant Heat Rate (NPHR) value, including operating parameters, fuel and equipment’s condition. The performance target of NPHR for Kaltim Teluk CFB CFPP based on specifications is 3430 kCal / kWh. Operational data shows that the NPHR of Unit #1 and Unit #2 is higher then the performance target. Analysis of operation and maintenance data showed that the low average net load and high condenser back pressure are the dominant problems that caused heat loss. One way to minimize heat loss and improve NPHR performance can be done by maximizing debris filter cleaning process through adjusting valve opening angle which can reduce differential pressure and finally reduce the backpressure at the condenser. With the flow simulation inside the debris filter, in order to achieve maximum flow rate with acceptable erosion rate, the optimum cleaning reached at valve opening angle 75°-60° and with this cleaning method, heat loss can be reduced 14.96 kCal/kWh and 50.09 kCal/kWh for unit #1 and unit #2 respectively.

Analisis Pengaruh Perubahan Beban Terhadap Heat Rate pada Unit Pembangkit Listrik Tenaga Uap (PLTU) Jeneponto 2 135 MW

The heat rate is a parameter that can indicate the reliability of the Steam Power Plant and is defined as the amount of heat from the fuel needed to produce 1 kWh of electricity. This study aims to analyze the effect of load changes on heat rate and its optimum value. Heat rates can be expressed in GPHR (Gross Plant Heat Rate) and NPHR (Net Plant Heat Rate). The method used is to identify and collect data for the last three years related to the determination of the heat rate, then perform data processing and analysis. In 2018, the optimum condition for unit 1 was obtained at a load of 125 MW is NPHR 2432.68 kcal/kWh, while Unit 2 at a load of 135 MW is NPHR value of 2489.65 kcal/kWh. In 2019 the optimum value for NPHR units 1 and 2 at a load of 137 MW are NPHR 2517.07 kcal/kWh and NPHR 2527.48 kcal/kWh, respectively. In 2020 the optimal value for Unit 1 is at a load of 135 MW, NPHR 2529.5 kcal/kWh, while Unit 2 is at a load of 137 MW, NPHR 2567.53 kcal/kWh. It can be concluded that an increase in load causes a decrease in the heat rate

Modified nonlinear function specification and temperature moving sensor to estimate the heat supply in a welding process

The estimation of the imposed heat rate in welding processes has always been an obstacle to improve the thermal efficiency of these processes. Thus, the use of inverse problem techniques is an alternative procedure to estimate the heat rate. In this study, the problem is highly nonlinear; therefore, the heat flux provided by the welding process is estimated by the iterative Function Specification method. This method was modified to estimate the heat supply based on the heat rate sensitivity coefficient, which represents the influence of the welding power in the temperatures of 304 stainless steel plates. In order to avoid the problem of low thermal sensitivity due to the movement of the welding source on the upper face of the plate, this methodology is based on the concept of temperature moving sensor. The software COMSOL was used to solve the three-dimensional heat diffusion equation with enthalpy function to model the phase change problem. 10 type K thermocouples, equally spaced, were attached by capacitive discharge on the opposite heated surface to measure the temperature. The efficiency of the process was calculated with the estimated net heat rate which ranged from 63% to 87%. The average efficiency obtained was 75% for this welding process. A relation between the energy rate given by the power supply and the estimated efficiency was also observed. The thermal efficiency of the arc decreases as the power increases. Thus, an analysis using the Taguchi method was performed in order to better understand the influence of the welding parameters on the efficiency of the process. It was concluded that with a significance level of 10%, the welding current and arc length have a strong correlation with thermal efficiency. These results are discussed and compared with results obtained experimentally by other researchers. Besides, an uncertainty analysis in the estimated heat rate is also presented.

HEAT RATE SYSTEM ANALYSIS IN THE STEAM POWER PLANT IN NIITANASA USING ENVIRONMENTALLY FRIENDLY LOW-CALORIE FUELS (REVISI)

The heat rate in a steam power plant is very important to know because it involves the amount of energy supply needed to produce electricity. This is done to determine the heat energy input from fuel needed in an electric energy. The purpose of this research is to analyze the heat rate needed in a steam power plant. The method used is the direct method, the required input is Gross kWh, Net kWh, coal fuel use, calorific value of the fuel. The type of fuel used is low calorie type of lignite. The results of the Gross Heat rate in January were seen 4,323.98 kcal / kWh while the Net Heat rate was 5,010.97 kcal / kWh. In December the Gross Heat rate was 4,141.72 kcal / kWh while the Net Heat rate was 4,992.96 kcal / kWh. This value is relatively high at a capacity of MW 100 MW.

Simulasi Pengaruh Excess Air terhadap Kinerja PLTU Kapasitas 12,5 MW pada Beban Bervariasi

The excess air is required to complete the combustion of fuel in the boiler. The amount of excess air differs from each power plant. It depends on the characteristic of the fuel such as the type and size of the fuel particle, the type of boiler and the type of combustion. Excess air that is too little will increase the unburnt fuel and while too much will reduce the power plant’s performance. This study uses CycleTempo version 5.0 software to investigate the effect of excess air on the performance of a 12.5 MW steam power plant. The fuel used is low-rank coal. The lower heating value of 16960.15 kcal. The composition of coal used is Carbon 45.74%, Hydrogen 2.68%, Moisture 20%, Nitrogen 0.46%, Oxygen 14.94%, Sulphur 0.19% and Ash 15.99%. The load on the turbine was varied by 70%, 80%, 90% and 100% from its design capacity. The excess air used starts from 0% to 50%, where the interval 10%. This study finds that the optimum excess air is approximated at 20%. The excess air over 20% will increase boiler ratings, net heat rate, air and fuel consumption. In reverse will reduce boiler efficiency and thermal efficiency. The changes of excess air did not affect the heat removed by the condenser and the power used by the pump.

Performance evaluation of a new conceptual combustion air preheating system in a 1000 MW coal-fueled power plant

An innovative design of combustion air preheating for large-scale coal-fueled power plants was proposed. Differing from the conventional air preheating system using a rotary regenerative air preheater, a cascade heating concept is adopted in the new configuration, where the air obtains heat from the feedwater, circulating water and flue gas in several tubular heat exchangers, which significantly diminishes the air leakages and the exergy destruction. The results of a detailed thermodynamic analysis show that, for a typical 1000 MW coal-fueled power plant, the net thermal efficiency increment can reach 0.49% points with a net heat rate reduction of 86.77 kJ/kWh, if the novel air preheating design is adopted instead of the conventional one. This is because the exergy efficiency of the air preheating process is promoted from 77.88% to 91.77% owing to the proposal, and the total exergy efficiency of the power plant rises by 0.48% points. The economic performance of the new design was examined as well, indicating that the dynamic payback period is only 5.30 years when the proposed air preheating system is employed to replace the conventional one. This work may be beneficial for enhancing the air preheating system and advancing coal-fired power production.

A simulation study on the performance of double skin façade through experimental design methods and analysis of variance

Systematic studies of the thermal fluid dynamic behaviour of building envelope systems through experiment analyses is limited by the relevant amount of time and high costs necessary to carry out a relevant number of tests covering all the possible configurations. Building simulation can be used as a tool to support the design of the experiments, i.e. to test, in a parametric way, different configurations to highlight the main trends, and therefore select the most relevant cases to be tested experimentally. Such a preliminary activity to maximize the effectiveness of the experiments may relates to both parametric analysis of indoor/outdoor boundary conditions, as well as parametric analysis of building envelope configurations. In the framework of a research project on double skin facade (DSF) systems where experiments are planned on a full-scale prototype, a model of a DSF is realized in a whole building energy software tool, and used to carry out a preliminary sensitivity analysis, by means of orthogonal array method and analysis of variance. Simulations were carried out in EnergyPlus, using the Airflow window module, and under steady-state conditions, a series of variables (cavity depth, venetian blinds tilt angle, airflow rate) have been investigated to assess their impact on the heat extract through the ventilation air and the total heat transmission between the outdoor and indoor environment. The results show that the main driver in the performance of DSF considering net heat rate transfer is the irradiation impinging on the façade in terms of boundary conditions, and coherently, the shading device is the feature that most affects the performance of the system among the characteristics of a DSF.

One feedwater heater taken out of service as a strategy to maintain full load and its effect on steam power cycle parameters and performance

The aim of this study is to analyze the suitability of one heater removal as a strategy for maintaining full load operation of steam power cycles when superheated and/or reheated temperatures (TSS, TRS) decrease and the effect on the net heat rate (HRNet). For this purpose, three regenerative cycles with different numbers of closed feedwater heaters were chosen. The cycles were analyzed at different steady states with Thermoflex software. Removing a heater has an important influence on the cycle operation and performance, leading to the redistribution of extraction mass flows, with the heater immediately downstream being the most affected. This may make it necessary to reduce the load of the cycle. However, when the highest pressure heater (highest PH) is removed from service, the changes are not so significant. When TSS and/or TRS decrease, the plant may not achieve full load operation. Nevertheless, if the highest PH is removed from service, it can help to recover full load. This is due to the decrease in the water/steam mass flow through the steam generator, which produces an increase in TSS and/or TRS. On the one hand, this measure leads to higher HRNet in comparison to that of the nominal conditions. On the other hand, there are certain conditions at which HRNet is lower than when all the heaters are in service and the values of TSS and/or TRS are low. Thus, for maintaining full load, the highest PH removal can be applied and cycle parameters optimized in order to reach a HRNet closer to its nominal value. The higher the number of closed feedwater heaters, the more adequate is the application of this strategy.

Heat flow due to time-delayed feedback

Many stochastic systems in biology, physics and technology involve discrete time delays in the underlying equations of motion, stemming, e. g., from finite signal transmission times, or a time lag between signal detection and adaption of an apparatus. From a mathematical perspective, delayed systems represent a special class of non-Markovian processes with delta-peaked memory kernels. It is well established that delays can induce intriguing behaviour, such as spontaneous oscillations, or resonance phenomena resulting from the interplay between delay and noise. However, the thermodynamics of delayed stochastic systems is still widely unexplored. This is especially true for continuous systems governed by nonlinear forces, which are omnipresent in realistic situations. We here present an analytical approach for the net steady-state heat rate in classical overdamped systems subject to time-delayed feedback. We show that the feedback inevitably leads to a finite heat flow even for vanishingly small delay times, and detect the nontrivial interplay of noise and delay as the underlying reason. To illustrate this point, and to provide an understanding of the heat flow at small delay times below the velocity-relaxation timescale, we compare with the case of underdamped motion where the phenomenon of “entropy pumping” has already been established. Application to an exemplary (overdamped) bistable system reveals that the feedback induces heating as well as cooling regimes and leads to a maximum of the medium entropy production at coherence resonance conditions. These observations are, in principle, measurable in experiments involving colloidal suspensions.

A novel cascade energy utilization to improve efficiency of double reheat cycle

Large mean terminal temperature difference of conventional regenerative air heater and high superheat degree of bleeding steams are the bottleneck of conventional steam rankine cycle, which limits the cycle for further efficiency improvement. In this study, a state-of-the-art double reheat power plant is selected as the reference cycle. A novel cycle covering steam, water and air process is invented based on the systematic combination of flue gas heat recovery and bleeding steam cascade energy utilization.Thermodynamic model is developed to analyze the performance improvement and exergy method is applied to validate and identify the cycle thermodynamic efficiency advantage. Simulation result presents novel cycle net heat rate is improved by 104.8 kJ/kWh and cycle net efficiency is increased by 0.61%. Feed water pump turbine inlet steam connection optimization accounts for 14 kJ/kWh net heat rate benefits for the novel cycle. Feasibility study proves it is possible to implement the novel cycle in a newly planned power plant. Based on techno-economic analysis, it is found that the total investment capital of novel cycle is 7.44 million US dollars and net annual revenue is 0.59 million US dollars compared with the reference cycle. Static capital investment paid back period is expected within 15 years in a newly planned power plant.

Feasibility Study of Turbine Inlet Air Cooling using Mechanical Chillers in Malaysia Climate

The performance of a gas turbine is dependent on the ambient air temperature. The gas turbine’s power output is reduced and heat rate is increased as a result of higher air temperature. The warm and humid climate in Malaysia, with its high ambient air temperature, has an adverse effect on the performance of gas turbine generators. Turbine Inlet Air Cooling is a power augmentation technology for gas turbines, which reduces the turbine inlet air temperature thereby improving the power output and heat rate of the machine. In this paper the effect of Turbine Inlet Air Cooling using electric chillers, on the performance of the LM6000PD Gas Turbine Generator (43.5MW ISO rating) is evaluated in the context of the Malaysian climate. GT Pro software is used to evaluate the performance of the gas turbine generator with ambient air temperature cooled to 12°C. The ambient design points used for the sizing of the chillers are the 0.4% Evaporative (Design Point A) and the 0.4% Cooling (Design Point B) design points for Sitiawan, Perak as published by ASHRAE. It is observed that Design Point A results in a chiller capacity of 1950RT which is sufficient to satisfy the cooling demand of the Turbine Inlet Air Cooling system for approximately 98% of the operating hours in a year, while Design Point B yields a smaller chiller size of 1700RT which is capable of meeting the Turbine Inlet Air Cooling requirement for approximately 72% of the annual operating hours. In terms of Gas Turbine performance, the net power output is increased by 27.5% and 32.11% while the net heat rate is reduced by 2.8% and 3.74% for Design Points A and B respectively. The substantial improvement in gas turbine net power output and heat rate as predicted by the GT Pro demonstrate that Turbine Inlet Air Cooling using electric chillers is effective as a power augmentation technology in Malaysia.

Energy, exergy, economic and environmental (4E) analyses of a conceptual solar aided coal fired 500 MWe thermal power plant with thermal energy storage option

In this paper, a conceptual cycle has been developed by integrating a solar field consisting of parabolic trough collectors with an operating 500MWe coal fired thermal power plant for preheating the condensate/feed water. The effect of solar aided feed water heating (SAFWH) has been studied separately for each feed water heater (except LP Heater-1 and deaerator) by placing a feed water heat exchanger (FWHE) parallel to the heater under study. Energy, exergy, economic and environmental (4E) analyses have performed on this conceptual cycle in fuel saving mode by complete substitution of bleed steam with solar energy. Performance parameters (Energy and exergy efficiency, net unit heat rate, fuel savings and solar contribution) and economic parameters (Levelised cost of electricity generation (LCoE), simple payback period) and environmental parameters (annual reductions in coal consumption, CO2 and ash generation) have been calculated. The results have shown that levelised cost (cents/kWh) and simple payback period (years) for solar aided feed water heating in HPH-7 without and with thermal storage are 5.045/5.196 and 5.13/6.21 respectively. Sensitivity analysis has been carried out to find out the sensitivity of LCoE with respect to discount rate, plant capacity factor and fuel cost.

Thermal Performance of Biomass-Fired Steam Power Plant

This paper presents results on the performance of 10 MW biomass-fired steam power plant. The main objective is to test the performance of the power plant using different type of biomass fuels: bagasse, corn stover, forest residues, and urban wood residues. The biomass fuel was mixed with sub-bituminous coal with fractions of 0–100%. The effect of excess combustion air, flue gas temperature, and the parasitic loads on the power plant performance was investigated. The output results from the heat and mass balance analysis include the monthly and annual electrical power generated, capacity factor (CF), boiler efficiency (BE), thermal efficiency, and gross and net heat rate. The results show a slightly decrease (1.7%) of the annual energy production when the biomass fractions increase from 6% to 100% but a substantial decrease of the CO2 equivalent emissions. A decrease of the excess combustion air from 25% to 5% will increase the boiler and thermal efficiencies and the annual energy output by 2%. This is mainly due to the reduction of the dry flue gas losses (DFGLs) with the reduction of the excess combustion air. A reduction of the parasitic loads from 10% to 2% will increase the power plant performance by 9%. This can be achieved by using more efficient pumps, fans, and conveyors in the power plant. A reduction of the flue gas temperature from 480 °F to 360 °F increases the power plant performance by 4.4% due to the reduction of the dry flue gas losses.