Energy–exergy analysis for performance improvement of Brayton–Rankine combined cycle system by utilizing a solar absorption refrigeration cycle (case study: Kahnuj Combined Cycle Power Plant)

Gas–steam combined cycle power plants are the most efficient electricity‐generation units based on fossil fuels. However, these power plants are prone to efficiency decrease in hot climates as high ambient temperatures adversely influence the gas turbine's output. The present study investigated the effect of incorporating a solar absorption refrigeration (SAR) system into an actual combined cycle power plant for the first time. First, the energy and exergy analyses were performed using THERMOFLOW software. Then, the influence of the ambient temperature (10°C–52.5°C) on the power plant's performance and its components was investigated. The SAR system was then used to cool the compressor's input air and improve the power generation capacity by employing TRNSYS software. The results showed that the power plant reached its maximum efficiency at an ambient temperature of 26.6°C. However, its overall efficiency and net power generation were dropped with a further increase in the ambient temperature. Employing the SAR system for each gas turbine in the power plant on a sunny day until 2 p.m. would decrease the compressor's input air temperature. For example, for the refrigeration capacities of 450, 700, and 1000 tons for each gas turbine, the temperature was reduced by nearly 3°C, 5°C, and 7°C, respectively. Under the same condition, power generation capacity improved by 12.5, 24, and 32.5 MW, and the overall efficiency rose by 0.6%, 1.4%, and 2%. Such an increase in power and efficiency occurred during peak demand, which was significant.


| INTRODUCTION
Due to the ever-increasing growth of the world's population and the growing demand for energy, especially electrical energy, research is continuously being carried out to evaluate the suitable alternatives of nonrenewable energy sources 1 or improve the performance of fossil fuel power plants with the approach of reducing energy consumption and increasing output power capacity.
The gas-steam (Brayton-Rankine) combined cycle power plants are one of the most common types of power plants based on natural gas.The main component of these combined cycle power plants is the gas turbine, which is being intensively developed to improve performance.However, an important issue about the gas turbine is that its output power decreases significantly as the ambient temperature increases. 2Therefore, cooling the inlet air of the gas turbine leads to a significant increase in turbine power output and improvement in efficiency.Even a slight decrease in the inlet air temperature can substantially impact the power output.This effect is because cooler air is denser, resulting in a higher mass flow rate and pressure ratio, ultimately increasing turbine output and efficiency. 3any studies have focused on various methods for cooling the compressor's inlet air.Baakeem et al. 4 theoretically investigated the influence of temperature and relative humidity on the performance of a typical gas turbine unit.They found that both parameters, that is, ambient temperature and humidity, significantly reduced the gas turbine performance.Compared to the standard conditions, the maximum power generation losses were 20%, 18%, and 17.5%.In another study, Baakeem et al. 5 investigated different cooling methods for lowering the inlet air temperature of gas turbines in the Riyadh power plant in Saudi Arabia.They considered various parameters, including the plant's annual net generation, fuel consumption rate, thermal efficiency, construction and exploitation costs, and return on asset duration.It was revealed that the multistage refrigeration system with a water-cooled condenser and the H 2 O-LiBr single-effect absorption refrigeration cycle had the best performance.Yazdi et al. 6 compared various cooling techniques employed in different climates in Iran.They considered energy, exergy, economic, and environmental factors.The findings highlighted the absorption chiller as the ideal cooling system for hot-climate cities. Chaker et al. 7,8 studied the effect of fog cooling on the performance of a gas turbine by analyzing the governing ambient conditions and measuring the cooling efficiency.They asserted that when the ambient temperature increased from the standard threshold to 35°C, the output power was reduced by 20%.Moreover, when the ambient temperature was 40°C, every 12°C reduction in the temperature using the fog system would reduce the turbine power output by 8 MW (10%).Barakat et al. 9 experimentally investigated the impact of saturated fogging and overspray on the part-load performance of microgas turbines (MGTs).The results demonstrated varying power output enhancements and reduced emissions with inlet fogging and overspray, highlighting their potential for improving MGT efficiency.Pourhedayat et al. 10 simulated an innovative hybrid M-cycle cooler and absorption refrigeration (AR) system for precooling the intake air of the Siemens SGT-750 gas turbine.They showed that the hybrid precooler is a cost-effective way to improve the performance of a gas turbine.Yokoyama et al. 11 performed technical and economic analyses using energy storage systems, that is, ice-storage condensed refrigeration systems, to compensate for peak electricity consumption in Osaka (Japan).They calculated the costs and achieved acceptable and optimum economic results.Mathioudakis et al. 12 studied the effect of using a water ammonia solution for cooling the compressor's inlet air.They found that the output power was increased by 22% as the compressor's inlet air temperature dropped from 35°C to 5°C.
Exergy analysis has been demonstrated to be the critical technique for finding and evaluating the thermodynamic inefficiencies of power plants 13 and making rational design decisions. 14Hence, numerous studies have been carried out to analyze combined cycle power plants from the exergy point of view.Ameri et al. 15 analyzed the 420 MW Neka combined cycle power plant to determine exergy losses in all the components.They demonstrated that 83% of the total exergy destruction occurred in the gas turbine, combustion chamber, duct burner, and heat recovery steam generator (HRSG).Energy and exergy analysis of the Al-Hussein thermal power plant in Jordan was performed by Al-Jundi. 16The results showed that the ratio of exergy loss to the total exergy loss in the boiler, turbine, and forced draft fan condenser was 77%, 13%, and 9%.Cihan et al. 17 performed the energy and exergy analyses on all components of a combined cycle power plant.They found that nearly 85% of the total exergy destruction stemmed from gas turbines, combustion chambers, and HRSG.Abuelnuor et al. 18 evaluated the exergy analysis of multiple units of the 180 MW Garri "2" combined cycle power plant.It was revealed that with 63% of total exergy loss, combustion chambers were responsible for most exergy destruction, while gas and steam turbines accounted for 13.6% and 6.4%, respectively.Pattanayak et al. 19 analyzed energy and exergy on a combined cycle power plant with a triple-pressure steam cycle and reheat.They found that the overall efficiency of the combined cycle power plant had an inverse relationship with inlet and exhaust pressure losses and the compressor's inlet air temperature.The exergy efficiency of HRSG was 87.2%, while the condenser had a 29% exergy efficiency.Khan and Tlili 20 analyzed the gas turbine and steam cycle equipped with HRSG.According to the results, the combined thermal efficiency was increased by 10% upon increasing the turbine inlet temperature from 1100°C to 1500°C.Altarawneh et al. 21analyzed the energy and exergy of a combined cycle power plant consisting of two gas turbines and one steam turbine with a full load of 400 MW in Jordan to identify the location and the devices with high energy losses.They made some recommendations to improve the performance of the power plant.Khaled et al. 22 used the enthalpy-entropy (energy-exergy) analysis approach to study the effects of ambient conditions on gas turbine output parameters.The results showed that as ambient temperature increased, the gas turbine output power and thermal efficiency decreased, and the specific fuel consumption increased.
The region's climate is crucial in selecting the appropriate cooling method for a power plant.Yang et al. 23 evaluated the AR cycle, fogging, and evaporative cooling techniques under different weather conditions from economic and thermodynamic points of view.They concluded that AR systems are more desirable in areas with ambient temperatures greater than 25°C and relative humidity higher than 40%.The AR system requires an energy source to evaporate the refrigerant, for which solar energy can be used. 24,25Solar energy is the most abundant renewable energy source that can provide unlimited thermal energy for the AR system by incorporating a solar farm comprising several collectors. 26However, no study has evaluated this promising alternative for cooling the turbine's inlet air in a combined gas-steam cycle power plant.
Kahnuj is located in a hot, humid region of Iran where the ambient temperature reaches 55°C on some days in the summer.Furthermore, due to this region's severe water scarcity conditions, using the evaporative cooling methods is unsuitable because of their high water consumption.These factors make the AR system a good candidate for cooling practices in Kahnuj.On the other hand, since the number of sunny days in Kahnuj during the year is high, using solar energy as a renewable and clean energy source can be considered a promising method.Hence, this study aimed to investigate the use of solar absorption refrigeration (SAR) systems for reducing gas turbine's inlet air temperature in an actual power plant in Kahnuj for the first time.First, energy and exergy analyses were performed to investigate the amount of exergy destruction in the main components.Second, SAR systems with different cooling capacities were designed to cool the compressor's inlet air by 3°C, 5°C, and 7°C.Finally, the effect of these cooling systems on the output power and overall efficiency were analyzed.

| Specifications of Kahnuj Combined Cycle Power Plant
The Kahnuj power plant is composed of two gas units comprising gas turbines (model V 94.2) with a nominal capacity of 162 MW and a steam unit with an integrated dual-pressure E-type steam turbine (Siemens model E30-16-1*6.3) with a nominal capacity of 160 MW.

| Gas turbine's inlet air cooling
The present study addressed utilizing the AR cycle with a solar thermal source to cool the gas turbine's inlet air, aiming to enhance the performance of the Kahnuj combined cycle power plant.In this section, the required amount of refrigeration is calculated, given the gas turbine's inlet air flow rate.The inlet air flow rate of every compressor of each gas turbine used in the design mode of the Kahnuj combined cycle power plant is provided in Table 1.
The present study investigates the reduction of inlet air temperature by 3°C, 5°C, and 7°C utilizing an AR system.The amount of refrigeration needed for each gas turbine unit, given the corresponding reduction in inlet air temperature, is provided in Table 2.This table also lists the AR's capacity based on the available market capacities. 27A B L E 1 Characteristics of the compressor's inlet air in Kahnuj Combined Cycle Power Plant (KCCPP).| 203

| AR system's heat source and weather conditions
The annual solar irradiation in the Kahnuj power plant is higher than 2000 kWh/m 2 . 28Such an amount of irradiation is high enough for utilizing solar energy to supply the energy demand.Parabolic trough collectors (PTCs) were used to supply the thermal energy the absorption system needed.In the proposed design, the gas turbine inlet air is not continuously cooled and is a function of solar radiation.Indeed, during the night, no cooling occurs since there is no solar irradiation.The ambient temperature is a factor that significantly affects the performance of gas turbines, absorption systems, and solar troughs.
The air temperature variations in this zone for different hours of the day are shown in Figure 1.As can be seen from the figure, the temperature varies from 10°C to 52.5°C during a year.

| Modeling combined cycle power plant, absorption refrigeration system, and solar trough
In the present study, THERMOFLOW software was used to investigate the energy and exergy flows of the Kahnuj combined cycle power plant.Besides, modeling of solarpowered absorption refrigeration system aimed at cooling the compressors' inlet air was performed in the TRNSYS software.

| Thermodynamic modeling
In the present study, the THERMOFLOW software was used to analyze the Kahnuj combined cycle power plant in both basic load and design conditions from the energy and exergy points of view.The modeling results were compared with the design data of the power plant, which showed an excellent agreement.At both base load and design conditions, two gas turbines in the power plant generate a total power of 279 MW.The outlet gases of these turbines enter the HSRG and then are fed into a steam turbine unit with a total output power of 157 MW at the base load.
The following equations were used for energy modeling of the power plant's components 21 : Compressor and pump Combustion chamber (5) where m denotes mass flow rate in kg/s, h is specific enthalpy in (kJ/kg), η is efficiency, LHV denotes the lower heating value in kJ/kg, W input and W output denote the input and output work in kW, Q input denotes the input thermal energy in kW, Q loss is the thermal energy loss in kW, i and e stand for the inlet and exit, f stands for fuel, and ist stands for isentropic process.
The following equations were employed for exergy modeling of the power plant's components 21,29,30 : Exergy balance (for steady-state conditions) Chemical exergy Physical exergy Compressor and pump des in out in (10)   Combustion chamber In Equations ( 7)-( 14), X represents total exergy in kW, W represents work in kW, y represents the mass fraction, x represents the mole fraction, R represents the gas constant in kJ/kg.K, T is the temperature in K, γ is the activity coefficient, h is specific enthalpy in kJ/kg, s represents specific entropy in kJ/kg.K, des stands for destruction, in and out, respectively, stand for input and output, ch stands for chemical, ph stands for physical, j stands for component j in a mixture, 0 stands for the reference environment, and f stands for fuel.

| Modeling of solar-powered absorption refrigeration system
The cooling mechanism of the compressor's inlet air is shown in Figure 2. The heat transfer fluid circulates in a closed loop between the solar trough farm and the refrigeration system, supplying the heat needed by the generator to produce high-pressure ammonia (NH 3 ) vapor.This vapor is liquified by passing through the condenser and enters the evaporator after its pressure is reduced in the expansion valve.The liquid NH 3 evaporates by absorbing heat from the atmospheric air in the evaporator.The NH 3 vapor is sent to the absorber, which is absorbed by water and pumped back to the generator to complete the absorption refrigeration cycle.The cooled air from the evaporator is fed to the gas turbine's compressor.The only heat source for the AR system is the solar trough farm, so no cooling is available without solar radiation (during the night and cloudy sky).

| Specifications and parameters related to the PTCs
The linear parabolic collector of type PT-5760, made by Gaia Solar Energy Co., was chosen based on the working temperature of the furnaces, high-energy consumption, and price.In this type of collector, the absorber pipe is covered by black chrome, and the space between the absorber tube and the glass cover is the vacuum.The dimensional parameters of a linear parabolic collector module of type PT-5760 are given in Table 3.
The Lippke model was used to develop the linear parabolic collector component as an input of the TRNSYS software. 32The thermal efficiency of the collector is defined as the ratio of the absorbed heat to the direct normal irradiance (DNI), ( ) I w m 2 , as below: where A is the coefficient for irradiation efficiency, which depends only on the cover types used on the absorber tube.
The coefficients B, C, and D describe the heat loss from the heat absorption components.These four coefficients, that is, A, B, C, and D, given the type of tube cover and the space between the absorption tube and glass cover, are listed in Table 4. Besides, T Δ denotes the temperature difference between the environment and heat transfer fluid (HTF).Finally, K represents the correction factor of the irradiance incident, which is a function of the incidence angle, I a , and calculates as follows: 3 | RESULTS AND DISCUSSION

| Validation
The results obtained from THERMOFLOW simulations and the experimental data of the Kahnuj power plant have been compared to validate the results.Table 5 shows the experimental and numerical results for different components.As can be seen, there is a negligible difference between the results, and an excellent agreement between the results is observed.

| Energy analysis
The energy modeling results are shown in Figure 3.As can be seen, the fuel supplies most of the input energy.Regarding the share of different components of the power plant in the internal and external energy consumption, it was found that the maximum energy loss rate (27.2%) occurs in the air-cooled condenser (ACC).Besides, 21.7%, 18.71%, 14.69%, 5.37%, and 1.8% of the total internal/external energy consumption are related to the feed water of HRSG, transformers, motors' energy consumption, condenser pumps' power consumption, and lightening and air conditioning, respectively.

| Exergy analysis
The exergy analysis was performed in the THERMO-FLOW software to understand the share of useful and accessible energies and determine the contribution of different components in the exergy destruction, the results of which are illustrated in Figure 4.The exergy analysis revealed that the fuel supplies a large part of the input exergy.Regarding the exergy output flow, only 36.05% of fuel energy is consumed for net power generation.Furthermore, most exergy losses are related to the gas turbine (41.54%) and chimney (10.55%).It is while that the exergy lost in the condenser is 1.42%.
The energy and exergy analyses showed that reducing the inlet air temperature of the gas turbine can be considered a potential candidate.Therefore, the effect of the compressor's inlet air temperature (environment temperature) on the performance of the Kahnuj T A B L E 5 The percentage of error between the power plant's actual and calculated outputs.| 207 combined cycle power plant is investigated in the following section.

| Effect of compressor's inlet air temperature on the performance of different power plant components
Given that the ambient temperature in the area of the Kahnuj power plant varies from 10°C to 52.5°C during a year, the effect of the temperature in this range on different components of the power plant was investigated.

| Effect of compressor's inlet air temperature on the gas turbine's efficiency
As shown in Figure 5, the gas turbine's efficiency steadily decreases as the compressor's inlet air temperature rises.This reduction may be due to the direct proportion of the turbine's output and air mass flow.
As the air temperature increases, its density decreases.
Given the constant volume of the air entering the turbine, this lower density corresponds to a reduced mass flow rate and turbine output.Moreover, more energy is required to compress the warmer air in the compressor, which further reduces the net work generated by the gas turbine.

| Effect of compressor's inlet air temperature on the output power of every gas turbine unit
Figure 6 shows the relationship between the turbine output power and the temperature of air entering the compressor.As illustrated, a decremental trend is observed for the gas turbine's generated power as the compressor's inlet air temperature increases from 10°C to 52.5°C.This decrease in the turbine's output may be F I G U R E 5 The effect of the compressor's inlet air temperature the gas turbine's efficiency.
ascribed to the safety measures regarding turbine operation.There is an upper limit for the temperature at which the turbine operates; surpassing this limit seriously damages the turbine's blades.As the compressor's inlet air temperature rises, the combustion gases become much hotter.The mass flow rate of fuel is reduced to avoid reaching the critical temperature, steadily decreasing the turbine's output power.

| Effect of compressor's inlet air temperature on the net output power
The simulation results revealed that by increasing the environment temperature from 10°C to 52.5°C, the net output power of the power plant is steadily decreased.As mentioned earlier, when hotter air enters the compressor, the mass flow rate of air passing through the compressor drops.Moreover, safety measure dictates reducing fuel consumption to avoid overheating and damaging turbine blades.These two factors lead to a constant decline in the net power output, as shown in Figure 7.

| Effect of compressor's inlet air temperature on the power plant's net efficiency
As illustrated in Figure 8, the net efficiency slightly increased with increasing temperature from 10°C to 26.6°C.This may be due to the reduced fuel consumption and proportionality between the air flow rate and the fuel consumption.Indeed, at this temperature, the power plant reached its design point, that is, its maximum efficiency.However, a further increase in the temperature resulted in a continuous decrease in the net efficiency.This reduction may be ascribed to the reduced inlet air mass flow and its adverse effects as discussed in the above sections.Therefore, it is concluded that cooling the compressor's inlet air could enhance the generated power of the power plant.The following section presents and discusses the results of utilizing the solar-powered absorption refrigeration system to cool the compressor's inlet air.

| Solar trough validation
The results obtained from the modeling solar trough with a linear parabolic collector using TRANSYS software were compared with the experimental data to validate the results.The experimental data were for solar trough SEGS VI power plant located at Mojave Desert, California, on a sunny July 18, 1991.The SEGS VI solar trough F I G R 6 The effect of the compressor's inlet air temperature on the power generated by each gas turbine.

F G U R E 7
The effect of the compressor's inlet air temperature on the net output power of the power plant.
F I G U R E 8 Effect of compressor's inlet air temperature on the power plant's net efficiency.
comprises linear parabolic collectors with a total area of 188,000 m 2 .The type of HTF used in this solar trough was Therminol VP-1, which is a synthetic oil. 33 comparison between the experimental and numerical results of the linear parabolic collector is made in Figure 9.It can be seen from the figure that the average difference between the experimental and modeling results is nearly 8%.This indicates a good agreement between the results.

| Solar trough's modeling results
First, modeling a solar trough with a total collector area of 3318 m 2 for a sunny day was performed to understand its thermodynamic performance better.The data of the solar trough is given in Table 6.The HTF temperature at the outlet of the solar trough, along with DNI and the net irradiation flux on the horizontal surface for a 24 h period, is shown in Figure 10.It can be seen from the figure that the DNI during the day is more uniform than the total irradiation flux on the horizontal surface.Since the parabolic collectors only absorb DNI on the absorber tube, the outlet HTF temperature is a function of DNI and is nearly more uniform on a sunny day.
The simulations were performed on a sunny day in summer to investigate the effect of using solar energy as a heat resource for the AR system.The energy needed for the AR system should be increased further to decrease the turbine's inlet air temperature.Therefore, the area of the solar trough must be increased to supply the needed heat transfer.In the middle of the day, when solar radiation is maximum, the ambient temperature is high, and the peak of power consumption also occurs at this time.Cooling the turbine gas inlet air will be particularly significant in such conditions.
The capacity of the AR system was determined, given the amount of cooling the components needed.In the following, the required area of solar trough for supplying thermal energy is calculated and designed based on the capacity of the refrigeration system.The solar trough for providing the thermal energy needed for AR systems with capacities of 450, 700, and 1000 tons of refrigeration (TOR) was designed and modeled (Table 7).The area of the solar trough was designed so that the thermal energy produced by the solar trough at hours at which maximum irradiation flux occurred did not exceed the energy required by the AR system.In other words, the solar trough should generate no excess thermal energy.In this case, in some hours of the day when the sun's radiation is maximum, the AR system works in its design capacity to cool the gas turbine inlet air.
Figure 11 shows the cooling rate of the compressor's inlet air by an AR system with a capacity of 450 TOR along with DNI.It is clear from the figure that the cooling rate of the compressor's inlet air is a function of DNI since DNI provides the energy needed for the AR system.In this case, the cooling of inlet air is done during the day when there is solar irradiation, and the refrigeration system would not work at night or during cloudy hours.
The cooling rate of gas turbine inlet air by the absorption refrigeration systems with different capacities along with the environment temperature is presented in Figure 12.As can be observed, the SAR system cooling rate for all three capacities steadily increases and reaches a maximum at 11 a.m., when the DNI peaks.After 11 a.m., a slight drop in the cooling rate is seen, followed by a constant decline after 2 p.m., which is consistent with the trend shown for DNI in Figure 10.In addition to the reduced DNI, increased ambient temperature is also responsible for the drop in air cooling in the last hours of the day.When the ambient temperature rises, the amount of heat released to the surroundings decreases, and the performance of the AR system is degraded as a result.
Figure 13 represents the inlet air temperature at different capacities of the SAR system.The higher the capacity of the absorption chiller, the lower the compressor's inlet air temperature will be.Moreover, the curves become closer to the ambient temperature curve after 2 p.m., demonstrating the weakened performance of the solar-powered AR system in reducing the compressor's inlet air temperature when DNI is decreased.
F I G U R E 10 The HTF temperature at the outlet of the solar trough, total irradiation flux on the horizontal surface, and DNI on sunny day.
The cooling rate of the gas turbine's inlet air by an AR system with a capacity of 450 TOR along with DNI.

F I G U R E 12
The cooling rate of the compressor's inlet for various capacities of the AR system.
F I G U R E 13 The compressor's inlet air various of the AR system.
F I G U R E 14 A rate of increase in the power generated and efficiency of the power plant at various capacities of the AR system for each gas turbine.
Figure 14 shows the increase in the power plant's generated power for different capacities of the absorption refrigeration system on a sunny day at 2:00 p.m.As discussed earlier, by increasing the capacity of the refrigeration system, the cooling work of the gas turbine inlet air is enhanced.This rise will positively affect the generated power and efficiency of the power plant.It should be noted that the capacity of the AR system, shown in Figure 14, is only used for cooling the inlet air of one of the gas turbines.Since there are two gas turbines in the Kahnuj power plant, there is a need for two refrigeration systems.

| CONCLUSION
In this study, an actual combined cycle power plant was simulated by THERMOFLOW software, and energy and exergy analyses were performed to find the most critical components decreasing the power plant's efficiency and destroying exergy.The energy-exergy study showed that the gas turbine caused the highest exergy destruction.Moreover, as the compressor's inlet air temperature rose, the turbine's output power and efficiency and the power plant's overall efficiency dropped.It was also demonstrated that solar-powered AR systems with collector areas of 3318, 5530, and 7603 m 2 could provide 450, 700, and 1000 tons of refrigeration, respectively.The SAR system's performance was directly influenced by DNI and could decrease the turbine's inlet air temperature and effectively improve the power plant's overall efficiency.
This study indicated that solar-powered AR systems could be coupled with combined cycle power plants to enhance performance.This cooling system utilizes a free, clean, unlimited energy source with minimum adverse environmental impacts.Suppose this system is economically competitive with other types cooling methods.In that case, it will provide the power generation industry with a nearly ideal approach improving plants' output and efficiency.This positive impact is even more significant in hot and arid countries struggling with limited water supplies.Therefore, the economic assessment of the proposed system is recommended in future studies to put further light on its economic viability.

2
The rate of refrigeration required to reduce the compressor's inlet air temperature for each gas turbine unit.refrigeration (TOR) capacity is the heat the ventilation or cooling system takes within 24 h from 1 ton of ice to melt it and change its phase to water at 0°C.ESFANDIARI ET AL.
Schematic diagram of the Brayton-Rankine cycle coupled with the SAR system.ESFANDIARI ET AL.| 205

F I G U R E 4
Power plant's exergy modeling results provided by the THERMOFLOW software (kJ).

F I U R E 9
The solar trough's output on July 18, 1991.T A B L E 6 Dimensional parameters of the solar trough.
the energy output flow, only 36.05% of it is consumed for generating net power.A total of 17.48%, 44.32%, and 2.15% of the net energy are lost in the condenser, chimney, and other miscellaneous losses.Notably, nearly 32.74% and 11.57% of this amount of energy exist in the form of sensible heat and latent heat, respectively.
a V: wind velocity.Regarding T A B L E 7 Data and results of modeling the various areas of the solar trough.