# A Novel Electricity and Freshwater Production System: Performance Analysis from Reliability and Exergoeconomic Viewpoints with Multi-Objective Optimization

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## Abstract

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## 1. Introduction

_{2}cycle, and a domestic water heater. For the case of wood as the biomass input, the highest exergy efficiency was calculated to be $40.10\%$. Ahmadi et al. [11] applied a steam Rankine cycle (SRC) to recover the waste energy of a micro gas turbine, and analyzed the system from thermodynamic, environmental, and exergoeconomic viewpoints. They also carried out optimization, and employed evolutionary algorithms to determine the optimum design parameters. Köse et al. [12] investigated the utilization of a steam Rankine cycle and an organic Rankine cycle (ORC) as the bottoming cycle of the gas turbine. They performed a parametric optimization to analyze the effects of various working fluids on the ORC subsystem. Optimum performance criteria were obtained for the overall system, including the SRC-ORC bottoming cycle with R141b as the working fluid. Optimal values of energy efficiency, exergy efficiency, and the net output power were evaluated as $22.60\%$, $64.80\%,$ and $780\text{}\mathrm{kW}$, respectively.

#### Main Novelties and Contributions

## 2. Materials and Methods

#### 2.1. System Description

#### 2.2. Modeling and Assumptions

- The operation of each process in the cycle is considered steady-state.
- Changes in the potential and kinetic energy rates are neglected; thus, only physical and chemical exergies are considered.
- Pressure drops in the steam Rankine cycle are neglected, and the pressure loss in the combustion chamber is taken to be $5\%$
- The input air composition is $79\%$ ${\mathrm{N}}_{2}$ and $21\%$ ${\mathrm{O}}_{2}$.
- The reference environment properties ${\mathrm{T}}_{0}$ and ${\mathrm{P}}_{0}$ are taken to be $298.15\text{}\mathrm{K}$ and $1.013\text{}\mathrm{bar}$, respectively.
- The temperature differences for the flows in all effects of the MED are equal.
- The spray of seawater in all effects of the MED occurs with an equal flow rate.

#### 2.2.1. Thermodynamic Modeling

#### 2.2.2. Exergoeconomic Analysis

#### 2.2.3. Main Performance Indices

#### 2.2.4. Reliability and Availability Analysis

#### 2.2.5. Multi-Objective Optimization and Accuracy Check

#### 2.3. Validation

## 3. Result and Discussion

#### 3.1. Main Operating Results

#### 3.2. Optimization and ANN Accuracy Check

#### 3.3. Reliability Analysis

## 4. Conclusions

- The highest exergy destruction value is related to the combustion chamber, mainly due to combustion reactions and heat transfer. Of the $\mathrm{18,237}\text{}\mathrm{kW}$ rate of total input exergy to the system, $3249\text{}\mathrm{kW}$ is destroyed in the combustion chamber.
- By coincident variation of compressor pressure ratio and air preheater effectiveness, net output power and exergy efficiency increase to maximum values and then decrease.
- The ANN employed can predict the results precisely with the ${\mathrm{R}}^{2}$ values 0.9978, 0.9883, 0.9890, and 0.9926 for freshwater production rate, net output power, exergy efficiency, and SUCP, respectively.
- For the ${\dot{\mathrm{m}}}_{\mathrm{fw}}-\mathsf{\epsilon}-\mathrm{SUCP}$ optimization scenario, using the TOPSIS decision-making method, optimum values of $45.10\%$, $14.27\text{}\mathrm{kg}\xb7{\mathrm{s}}^{-1}$, $12.95\text{}\mathrm{USD}\xb7{\mathrm{GJ}}^{-1}$, and $8141\text{}\mathrm{kW}$ are obtained for exergy efficiency, freshwater production rate, SUCP, and net output power, respectively.
- Based on the reliability and availability analysis, the probability of the healthy working state of all components and subsystems is determined to be $88.4403\%;$ it is shown that the system is $87.74\%$ available in the 20-year lifetime.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## Nomenclature

Symbols | |

$\mathrm{A}$ | Availability |

$\mathrm{ANN}$ | Artificial neural network |

$\mathrm{c}$ | Cost per unit exergy ($\mathrm{USD}\xb7{\mathrm{GJ}}^{-1}$) |

$\dot{\mathrm{C}}$ | Cost rate ($\mathrm{USD}\xb7{\mathrm{year}}^{-1}$) |

$\mathrm{CDF}$ | Cumulative distribution function |

$\mathrm{CEPCI}$ | Chemical Engineering Plant Cost Index |

$\mathrm{CRF}$ | Capital recovery factor |

$\mathrm{DER}$ | Distributed energy resource |

$\mathrm{EES}$ | Engineering Equation Solver |

$\mathrm{ex}$ | Specific exergy ($\mathrm{kJ}\xb7{\mathrm{kg}}^{-1}$) |

$\dot{\mathrm{E}}\mathrm{x}$ | Exergy rate (kW) |

$\mathrm{GOR}$ | Gain output ratio |

$\mathrm{GTC}$ | Gas turbine cycle |

$\mathrm{h}$ | Specific enthalpy ($\mathrm{kJ}\xb7{\mathrm{kg}}^{-1}$) |

$\mathrm{HRSG}\text{}$ | Heat recovery steam generator |

${\mathrm{i}}_{\mathrm{r}}$ | Interest rate |

$\mathrm{IGCC}\text{}$ | Integrated gasification combined cycle |

$\mathrm{LHV}\text{}$ | Lower heating value ($\mathrm{kJ}\xb7{\mathrm{kg}}^{-1}$) |

$\dot{\mathrm{m}}$ | Mass flow rate ($\mathrm{kg}\xb7{\mathrm{s}}^{-1}$) |

$\mathrm{MED}$ | Multi-effect distillation |

$\mathrm{MC}$ | Moisture content ($\%$) |

$\mathrm{MOPSO}$ | Multi-objective PSO |

$\mathrm{MTTF}\text{}$ | Mean time to failure |

$\mathrm{MTTR}$ | Mean time to repair |

$\mathrm{N}$ | Operation hours per year ($\mathrm{hours}$) |

$\mathrm{n}$ | Cycle lifetime ($\mathrm{years}$) |

$\mathrm{ORC}$ | Organic Rankine cycle |

$\mathrm{P}$ | Pressure ($\mathrm{MPa}$) |

$\mathrm{PDF}$ | Probability density function |

$\mathrm{Pr}$ | Probability |

$\mathrm{PSO}$ | Particle swarm optimization |

$\mathrm{PPTD}$ | Pinch point temperature difference ($\mathrm{K}$) |

$\dot{\mathrm{Q}}$ | Heat transfer rate ($\mathrm{kW}$) |

${\mathrm{r}}_{\mathrm{P}}$ | Pressure ratio |

$\overline{\mathrm{R}}$ | Universal gas constant ($\mathrm{kJ}\xb7{\mathrm{kmol}}^{-1}\xb7{\mathrm{K}}^{-1}$) |

$\mathrm{R}$ | Reliability |

$\mathrm{s}$ | Specific entropy ($\mathrm{kJ}\xb7{\mathrm{kg}}^{-1}\xb7{\mathrm{K}}^{-1}$) |

$\mathrm{SRC}$ | Steam Rankine cycle |

$\mathrm{SPECO}$ | Specific exergy costing |

$\mathrm{SUCP}\text{}$ | Sum unit cost of product ($\mathrm{USD}\xb7{\mathrm{GJ}}^{-1}$) |

$\mathrm{T}$ | Temperature ($\mathrm{K}$) |

$\mathrm{t}$ | Time ($\mathrm{s}$) |

$\mathrm{TOPSIS}\text{}$ | Technique for order of preference by similarity to ideal solution |

$\dot{\mathrm{W}}$ | Electrical power ($\mathrm{kW}$) |

$\mathrm{WHR}$ | Waste heat recovery |

$\mathrm{Y}$ | Mole fraction |

$\mathrm{Z}$ | Purchased equipment cost ($\mathrm{USD}$) |

$\dot{\mathrm{Z}}$ | Levelized cost ($\mathrm{USD}\xb7{\mathrm{year}}^{-1}$) |

Subscripts | |

$\mathrm{AC}$ | Air compressor |

$\mathrm{AP}$ | Air preheater |

$\mathrm{CC}$ | Combustion chamber |

$\mathrm{ch}$ | Chemical |

$\mathrm{CI}$ | Capital investment |

$\mathrm{Comp}$ | Compressor |

$\mathrm{Cond}$ | Condenser |

$\mathrm{C}.\mathrm{V}.$ | Control volume |

$\mathrm{D}$ | Destruction |

$\mathrm{ex}$ | Exergy |

$\mathrm{fw}$ | Freshwater |

$\mathrm{g}$ | Gasifier |

$\mathrm{GT}$ | Gas turbine |

$\mathrm{in}$ | Inlet |

$\mathrm{is}$ | Isentropic |

$\mathrm{GT}$ | Gas turbine |

$\mathrm{in}$ | Inlet |

$\mathrm{invs}$ | Investment |

$\mathrm{is}$ | Isentropic |

$\mathrm{k}$ | ${\mathrm{k}}^{\mathrm{th}}$ component |

$\mathrm{L}$ | Loss |

$\mathrm{net}$ | Net value |

$\mathrm{OM}$ | Operation and maintenance |

$\mathrm{out}$ | Outlet |

$\mathrm{ph}$ | Physical |

$\mathrm{pump}$ | Pump |

$\mathrm{q}$ | Heat transfer |

$\mathrm{ref}$ | Reference |

$\mathrm{ST}$ | Steam turbine |

$\mathrm{sys}$ | System |

$\mathrm{sup}$ | Superheating |

$\mathrm{W}$ | Work |

$1,\text{}2,\text{}\dots $ | Cycle locations |

$0$ | Dead state |

$\mathrm{tot}$ | Total |

$\mathrm{VG}$ | Vapor generator |

$\mathrm{W}$ | Work |

$1,\text{}2,\text{}\dots $ | Cycle locations |

$0$ | Dead state |

Greek Symbols | |

$\mathsf{\lambda}$ | Failure rate |

$\mathsf{\mu}$ | Repair rate |

${\mathsf{\varphi}}_{\mathrm{r}}$ | Maintenance factor |

$\mathsf{\Psi}$ | Coefficient of the fuel chemical exergy |

$\mathsf{\epsilon}$ | Exergy efficiency ($\%$) |

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**Figure 1.**Schematic of the proposed integrated gasification combined cycle for electricity and freshwater production.

**Figure 5.**Sankey diagram showing the exergy flow rates and exergy destruction, and loss rates for the cogeneration system.

**Figure 6.**Effect of varying compressor pressure ratio and air preheater effectiveness on the (

**a**) freshwater production, (

**b**) net output power, (

**c**) exergy efficiency, and (

**d**) sum unit cost of product.

**Figure 7.**Comparative diagram of predicted data vs. actual data for (

**a**) freshwater production, (

**b**) net output power, (

**c**) exergy efficiency, and (

**d**) sum unit cost of product.

**Figure 8.**Pareto front of the optimum solution points for several optimization scenarios, (

**a**) ${\dot{\mathrm{m}}}_{\mathrm{fw}}$-${\dot{\mathrm{W}}}_{\mathrm{net}}$, (

**b**) $\mathrm{SUCP}$-${\dot{\mathrm{m}}}_{\mathrm{fw}}$, (

**c**) ${\dot{\mathrm{m}}}_{\mathrm{fw}}$-$\mathsf{\epsilon}$, and (

**d**) ${\dot{\mathrm{m}}}_{\mathrm{fw}}$-$\mathsf{\epsilon}$-$\mathrm{SUCP}$.

**Figure 9.**Scatter distribution of design decision variables, (

**a**) compression ratio, (

**b**) air preheater efficiency, (

**c**) feedwater temperature, and (

**d**) superheating temperature difference.

**Figure 11.**Variations in trend of the availability for each of the subsystems over the plant’s lifetime.

Parameter | Value | Unit |
---|---|---|

Reference pressure, ${\mathrm{P}}_{0}$ | $1.013$ | $\mathrm{bar}$ |

Reference temperature, ${\mathrm{T}}_{0}$ | $298.15$ | $\mathrm{K}$ |

Isentropic efficiency of gas turbines, ${\mathsf{\eta}}_{\mathrm{is},\mathrm{GT}}$ | $86$ | $\%$ |

Isentropic efficiency of steam turbine, ${\mathsf{\eta}}_{\mathrm{is},\mathrm{ST}}$ | $88$ | $\%$ |

Isentropic efficiency of compressors,${\text{}\mathsf{\eta}}_{\mathrm{is},\mathrm{Comp}}\text{}$ | $86$ | $\%$ |

Isentropic efficiency of pump, ${\mathsf{\eta}}_{\mathrm{is},\mathrm{Pump}}$ | $86$ | $\%$ |

Pressure ratio of compressors, ${\mathrm{r}}_{\mathrm{P}}$ | $4$ | $-$ |

Combustion product temperature, ${\mathrm{T}}_{11}$ | $1500$ | $\mathrm{K}$ |

Combustion chamber pressure drop, $\mathsf{\Delta}{\mathrm{P}}_{\mathrm{CC}}$ | 5 | % |

Gasification temperature, ${\mathrm{T}}_{\mathrm{g}}$ | $1073.15$ | $\mathrm{K}$ |

Gasification pressure, ${\mathrm{P}}_{\mathrm{g}}$ | 4.052 | $\mathrm{bar}$ |

Mass flow rate of biomass, ${\dot{\mathrm{m}}}_{\mathrm{f}}$ | $1.25$ | $\mathrm{kg}\xb7{\mathrm{s}}^{-1}$ |

Moisture content in biomass | 20 | % |

Temperature of water entering intercooler, ${\mathrm{T}}_{19}$ | 303.15 | K |

Temperature of water exiting intercooler, ${\mathrm{T}}_{20}$ | 311.15 | K |

PPTD of Intercooler, ${\mathrm{PPTD}}_{\mathrm{intercooler}}$ | $17$ | $\mathrm{K}$ |

Effectiveness of air preheater, ${\mathsf{\eta}}_{\mathrm{AP}}$ | 75 | % |

Stack temperature, ${\mathrm{T}}_{14}$ | $423.15$ | $\mathrm{K}$ |

PPTD of HRSG, ${\mathrm{PPTD}}_{\mathrm{HRSG}}$ | $10$ | $\mathrm{K}$ |

APTD of HRSG, A${\mathrm{PTD}}_{\mathrm{HRSG}}$ | $10$ | $\mathrm{K}$ |

Steam turbine inlet pressure, ${\mathrm{P}}_{16}$ | $20$ | $\mathrm{bar}$ |

Steam turbine outlet pressure, ${\mathrm{P}}_{17}$ | $0.25$ | $\mathrm{bar}$ |

MED feedwater temperature, ${\mathrm{T}}_{24}$ | 318.15 | $\mathrm{K}$ |

Seawater temperature, ${\mathrm{T}}_{21}$ | 303.15 | $\mathrm{K}$ |

Salinity of seawater | 42 | $\mathrm{g}\xb7{\mathrm{kg}}^{-1}$ |

Salinity of brine | 70 | $\mathrm{g}\xb7{\mathrm{kg}}^{-1}$ |

Number of MED stages, ${\mathrm{N}}_{\mathrm{sta}}$ | 6 | $-$ |

Temperature difference between effects, ${\mathsf{\Delta}\mathrm{T}}_{\mathrm{eff}}$ | $2.8$ | $\mathrm{K}$ |

MED final stage temperature | 321.15 | $\mathrm{K}$ |

Component | Cost Function | Ref. Year | Cost Index |
---|---|---|---|

Air compressor | ${\mathrm{Z}}_{\mathrm{AC}}=\left(\frac{71.1\times {\dot{\mathrm{m}}}_{2}}{0.9-{\mathsf{\eta}}_{\mathrm{is},\mathrm{AC}}}\right)\left(\frac{{\mathrm{P}}_{3}}{{\mathrm{P}}_{2}}\right)\left[\mathrm{ln}\left(\frac{{\mathrm{P}}_{3}}{{\mathrm{P}}_{2}}\right)\right]$ | 1994 | 368 |

Compressor 1 | ${\mathrm{Z}}_{\mathrm{Com}1}=\left(\frac{71.1\times {\dot{\mathrm{m}}}_{5}}{0.9-{\mathsf{\eta}}_{\mathrm{is},\mathrm{Com}}}\right)\left(\frac{{\mathrm{P}}_{6}}{{\mathrm{P}}_{5}}\right)\left[\mathrm{ln}\left(\frac{{\mathrm{P}}_{6}}{{\mathrm{P}}_{5}}\right)\right]$ | 1994 | 368 |

Compressor 2 | ${\mathrm{Z}}_{\mathrm{Com}2}=\left(\frac{71.1\times {\dot{\mathrm{m}}}_{7}}{0.9-{\mathsf{\eta}}_{\mathrm{is},\mathrm{Com}}}\right)\left(\frac{{\mathrm{P}}_{8}}{{\mathrm{P}}_{7}}\right)\left[\mathrm{ln}\left(\frac{{\mathrm{P}}_{8}}{{\mathrm{P}}_{7}}\right)\right]$ | 1994 | 368 |

Intercooler | ${\mathrm{Z}}_{\mathrm{intercooler}}=8000{\left(\text{}\frac{{\mathrm{A}}_{\mathrm{intercooler}}}{100}\text{}\right)}^{0.6}$ | 2000 | 394.1 |

Air preheater | ${\mathrm{Z}}_{\mathrm{AP}}=4122\times {\left(\frac{{\dot{\mathrm{m}}}_{12}\left({\mathrm{h}}_{12}-{\mathrm{h}}_{13}\right)}{{\mathrm{U}}_{\mathrm{AP}}{\mathsf{\Delta}\mathrm{T}}_{\mathrm{lm},\mathrm{AP}}}\right)}^{0.6}$ | 1994 | 368 |

Gas turbine 1 | ${\mathrm{Z}}_{\mathrm{GT}1}=\left(\frac{479.34\times {\dot{\mathrm{m}}}_{9}}{0.92-{\mathsf{\eta}}_{\mathrm{is},\mathrm{GT}}}\right)\text{}\mathrm{ln}\left(\frac{{\mathrm{P}}_{9}}{{\mathrm{P}}_{10}}\right)\times \left[1+\mathrm{exp}\left(0.036\times {\mathrm{T}}_{9}-54.4\right)\right]$ | 1994 | 368 |

Gas turbine 2 | ${\mathrm{Z}}_{\mathrm{GT}2}=\left(\frac{479.34\times {\dot{\mathrm{m}}}_{11}}{0.92-{\mathsf{\eta}}_{\mathrm{is},\mathrm{GT}}}\right)\text{}\mathrm{ln}\left(\frac{{\mathrm{P}}_{11}}{{\mathrm{P}}_{12}}\right)\times \left[1+\mathrm{exp}\left(0.036\times {\mathrm{T}}_{11}-54.4\right)\right]$ | 1994 | 368 |

Combustion chamber | ${\mathrm{Z}}_{\mathrm{CC}}=\left(\frac{46.08\times {\dot{\mathrm{m}}}_{10}}{0.995-\left(\frac{{\mathrm{P}}_{11}}{{\mathrm{P}}_{10}}\right)\text{}}\right)\left[1+\mathrm{exp}\left(0.018\times {\mathrm{T}}_{11}-26.4\right)\right]$ | 1994 | 368 |

Gasifier | ${\mathrm{Z}}_{\mathrm{G}}=1600{\left({\dot{\mathrm{m}}}_{\mathrm{dry},\mathrm{biomass}}\right)}^{0.67}$ | 1994 | 368 |

Steam turbine | ${\mathrm{Z}}_{\mathrm{ST}}=3880.5\times {\dot{\mathrm{W}}}_{\mathrm{ST}}{}^{0.7}\left(1+{\left(\frac{0.05}{0.92-{\mathsf{\eta}}_{\mathrm{is},\mathrm{ST}}}\right)}^{3}\right)\left(1+5\times {2.71}^{\frac{\left({\mathrm{T}}_{16}-866\right)}{10.42}}\right)\text{}$ | 2003 | 402 |

Pump | ${\mathrm{Z}}_{\mathrm{Pump}}=2100{\left(\frac{{\dot{\mathrm{W}}}_{\mathrm{Pump}}}{10}\right)}^{0.26}{\left(\frac{1-{\mathsf{\eta}}_{\mathrm{is},\mathrm{Pump}}}{{\mathsf{\eta}}_{\mathrm{is},\mathrm{Pump}}}\right)}^{0.5}$ | 2000 | 394.1 |

HRSG | ${\mathrm{Z}}_{\mathrm{HRSG}}$ = 6570$\times $ [${\left(\frac{{\dot{\mathrm{Q}}}_{\mathrm{ec}}}{{\mathsf{\Delta}\mathrm{T}}_{\mathrm{lm},\mathrm{ec}}}\right)}^{0.8}+{\left(\frac{{\dot{\mathrm{Q}}}_{\mathrm{ev}}}{{\mathsf{\Delta}\mathrm{T}}_{\mathrm{lm},\mathrm{ev}}}\right)}^{0.8}+{\left(\frac{{\dot{\mathrm{Q}}}_{\mathrm{sup}}}{{\mathsf{\Delta}\mathrm{T}}_{\mathrm{lm},\mathrm{sup}}}\right)}^{0.8}$] + 21,276 $\times $ ${\dot{\mathrm{m}}}_{16}$ + 1184.4 $\times $ ${\dot{\mathrm{m}}}_{13}{}^{1.2}$ | 1994 | 368 |

MED | ${\mathrm{Z}}_{\mathrm{MED}}$ = 6291 $\times {\dot{\mathrm{m}}}_{22}{}^{0.865}$ $\times $ [1 −${\text{}\mathrm{f}}_{\mathrm{HE}}+{\text{}\mathrm{f}}_{\mathrm{HE}}\times {\left(\frac{{\mathrm{N}}_{\mathrm{sta}}}{{\mathrm{N}}_{\mathrm{ref}}}\right)}^{1.277}\times {\left(\frac{{\mathrm{T}}_{\mathrm{ref}}}{{\mathrm{T}}_{18}-273.15}\right)}^{1.048}$], ${\text{}\mathrm{f}}_{\mathrm{HE}}=0.4$, ${\mathrm{N}}_{\mathrm{ref}}=8$, ${\mathrm{T}}_{\mathrm{ref}}=70$ | 2018 | 638.1 |

Component | Cost Rate Equation | Auxiliary Equations |
---|---|---|

Air compressor | ${\dot{\mathrm{C}}}_{2}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{AC}}+{\dot{\mathrm{Z}}}_{\mathrm{AC}}={\dot{\mathrm{C}}}_{3}$ | ${\mathrm{c}}_{\mathrm{W},\mathrm{AC}}={\mathrm{c}}_{\mathrm{W},\mathrm{GT}2}$, ${\mathrm{c}}_{2}=0$ |

Compressor 1 | ${\dot{\mathrm{C}}}_{5}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{Com}1}+{\dot{\mathrm{Z}}}_{\mathrm{Com}1}={\dot{\mathrm{C}}}_{6}$ | ${\mathrm{c}}_{\mathrm{W},\mathrm{Com}1}={\mathrm{c}}_{\mathrm{W},\mathrm{GT}1}$, ${\mathrm{c}}_{5}=0$ |

Compressor 2 | ${\dot{\mathrm{C}}}_{7}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{Com}2}+{\dot{\mathrm{Z}}}_{\mathrm{Com}2}={\dot{\mathrm{C}}}_{8}$ | ${\mathrm{c}}_{\mathrm{W},\mathrm{Com}2}={\mathrm{c}}_{\mathrm{W},\mathrm{GT}2}$ |

Intercooler | ${\dot{\mathrm{C}}}_{19}+{\dot{\mathrm{C}}}_{6}+{\dot{\mathrm{Z}}}_{\mathrm{intercooler}}={\dot{\mathrm{C}}}_{20}+{\dot{\mathrm{C}}}_{7}\text{}$ | ${\mathrm{c}}_{7}={\mathrm{c}}_{6},{\text{}\mathrm{c}}_{19}=0\text{}$ |

Air preheater | ${\dot{\mathrm{C}}}_{8}+{\dot{\mathrm{C}}}_{12}+{\dot{\mathrm{Z}}}_{\mathrm{AP}}={\dot{\mathrm{C}}}_{9}+{\dot{\mathrm{C}}}_{13}\text{}$ | ${\mathrm{c}}_{13}={\mathrm{c}}_{12}\text{}$ |

Gas turbine 1 (GT1) | ${\dot{\mathrm{C}}}_{9}+{\dot{\mathrm{Z}}}_{\mathrm{GT}1}={\dot{\mathrm{C}}}_{10}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{GT}1}$ | ${\mathrm{c}}_{10}={\mathrm{c}}_{9}\text{}$ |

Gas turbine 2 (GT2) | ${\dot{\mathrm{C}}}_{11}+{\dot{\mathrm{Z}}}_{\mathrm{GT}2}={\dot{\mathrm{C}}}_{12}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{GT}2}$ | ${\mathrm{c}}_{12}={\mathrm{c}}_{11}\text{}$ |

Combustion chamber | ${\dot{\mathrm{C}}}_{4}+{\dot{\mathrm{C}}}_{10}+{\dot{\mathrm{Z}}}_{\mathrm{CC}}={\dot{\mathrm{C}}}_{11}\text{}$ | |

Gasifier | ${\dot{\mathrm{C}}}_{1}+{\dot{\mathrm{C}}}_{3}+{\dot{\mathrm{Z}}}_{\mathrm{GS}}={\dot{\mathrm{C}}}_{4}$ | |

Steam turbine (S$\mathrm{T}$) | ${\dot{\mathrm{C}}}_{16}+{\dot{\mathrm{Z}}}_{\mathrm{ST}}={\dot{\mathrm{C}}}_{17}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{ST}}$ | ${\mathrm{c}}_{17}={\mathrm{c}}_{16}$ |

Pump | ${\dot{\mathrm{C}}}_{18}+{\dot{\mathrm{C}}}_{\mathrm{W},\mathrm{Pump}}+{\dot{\mathrm{Z}}}_{\mathrm{Pump}}={\dot{\mathrm{C}}}_{15}$ | ${\mathrm{c}}_{\mathrm{W},\mathrm{Pump}}={\mathrm{c}}_{\mathrm{W},\mathrm{ST}}$ |

HRSG | ${\dot{\mathrm{C}}}_{13}+{\dot{\mathrm{C}}}_{15}+{\dot{\mathrm{Z}}}_{\mathrm{HRSG}}={\dot{\mathrm{C}}}_{14}+{\dot{\mathrm{C}}}_{16}\text{}$ | ${\mathrm{c}}_{14}={\mathrm{c}}_{13}\text{}$ |

First stage of MED | ${\dot{\mathrm{C}}}_{17}+{\dot{\mathrm{C}}}_{21}+{\dot{\mathrm{Z}}}_{\mathrm{MED}}={\dot{\mathrm{C}}}_{18}+{\dot{\mathrm{C}}}_{22}+{\dot{\mathrm{C}}}_{23}$ | ${\mathrm{c}}_{18}={\mathrm{c}}_{17}\text{},{\text{}\mathrm{c}}_{21}={\text{}\mathrm{c}}_{23}\text{}$ |

$\mathbf{Failure}\text{}\mathbf{Rate},\text{}\mathbf{\lambda}\left(\mathbf{p}\mathbf{e}\mathbf{r}\mathbf{D}\mathbf{a}\mathbf{y}\right)$ | Value | $\mathbf{Repair}\text{}\mathbf{Rate},\text{}\mathit{\lambda}\left(\mathbf{p}\mathbf{e}\mathbf{r}\mathbf{D}\mathbf{a}\mathbf{y}\right)$ | Value |
---|---|---|---|

${\mathsf{\lambda}}_{\mathrm{IGC}}$ | $0.0033$ | ${\mathsf{\mu}}_{\mathrm{IGC}}$ | $0.03$ |

${\mathsf{\lambda}}_{\mathrm{HRSG}}$ | $0.002$ | ${\mathsf{\mu}}_{\mathrm{HRSG}}$ | $0.19$ |

${\mathsf{\lambda}}_{\mathrm{SRC}}$ | $0.00274$ | ${\mathsf{\mu}}_{\mathrm{SRC}}$ | $0.14$ |

Gasifier | ||||
---|---|---|---|---|

Gas Yield | Present Work | Gholamian et al. [10] | Zainal et al. [42] | Experiment [43] |

${\mathrm{H}}_{2}$ percentage | $21.06$ | $21.6$ | $21.06$ | $15.23$ |

$\mathrm{CO}$ percentage | $19.28$ | $20.48$ | $19.61$ | $23.04$ |

${\mathrm{CO}}_{2}$ percentage | $12.85$ | $12.4$ | $12.01$ | $16.42$ |

${\mathrm{CH}}_{4}$ percentage | $0.67$ | $1.03$ | $0.64$ | $1.58$ |

${\mathrm{N}}_{2}$ percentage | $46.14$ | $44.48$ | $46.68$ | $42.31$ |

${\mathrm{O}}_{2}$ percentage | $0$ | $0$ | $0$ | $1.42$ |

$\mathrm{RSMD}$ | $0.463$ | $1.0863$ | $\mathrm{N}/\mathrm{A}$ | $\mathrm{N}/\mathrm{A}$ |

MED | ||||

Parameter | Present work | Ref. [44] | Error ($\%$) | |

Water production rate ($\mathrm{kg}\xb7{\mathrm{s}}^{-1}$) | 0.8225 | 0.8311 | 1.03 | |

Salinity of brine ($\mathrm{g}\xb7{\mathrm{kg}}^{-1}$) | 55.00 | 55.91 | 1.62 | |

Operating pressure of first effect ($\mathrm{bar}$) | 0.275 | 0.265 | 3.77 | |

Performance ratio | 9.452 | 9.5576 | 1.1 |

Performance Index | Value | Unit |
---|---|---|

Net output power (${\dot{\mathrm{W}}}_{\mathrm{net}}$) | 8347 | kW |

Produced freshwater rate (${\dot{\mathrm{m}}}_{\mathrm{fw}}$) | 11.70 | $\mathrm{kg}\xb7{\mathrm{s}}^{-1}$ |

Exergy efficiency ($\mathsf{\epsilon}$) | 46.22 | $\%\text{}$ |

SUCP | 13.14 | $\mathrm{USD}\xb7{\mathrm{GJ}}^{-1}$ |

State | $\mathbf{Probability},\text{}\mathbf{P}\left[\mathbf{\%}\right]$ |
---|---|

1 | $87.4403$ |

2 | $9.6184$ |

3 | $0.9204$ |

4 | $1.7113$ |

5 | $0.1012$ |

6 | $0.0108$ |

7 | $0.1882$ |

8 | $0.002$ |

Subsystem | $\mathbf{Availability}\text{}\left[\mathit{\%}\right]$ |
---|---|

Integrated gasification cycle (IGC) | $90.09$ |

Heat recovery steam generator (HRSG) | $98.96$ |

Steam Rankine cycle (SRC) | $98.08$ |

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## Share and Cite

**MDPI and ACS Style**

Hamrang, F.; Mahmoudi, S.M.S.; Rosen, M.A.
A Novel Electricity and Freshwater Production System: Performance Analysis from Reliability and Exergoeconomic Viewpoints with Multi-Objective Optimization. *Sustainability* **2021**, *13*, 6448.
https://doi.org/10.3390/su13116448

**AMA Style**

Hamrang F, Mahmoudi SMS, Rosen MA.
A Novel Electricity and Freshwater Production System: Performance Analysis from Reliability and Exergoeconomic Viewpoints with Multi-Objective Optimization. *Sustainability*. 2021; 13(11):6448.
https://doi.org/10.3390/su13116448

**Chicago/Turabian Style**

Hamrang, Farzad, S. M. Seyed Mahmoudi, and Marc A. Rosen.
2021. "A Novel Electricity and Freshwater Production System: Performance Analysis from Reliability and Exergoeconomic Viewpoints with Multi-Objective Optimization" *Sustainability* 13, no. 11: 6448.
https://doi.org/10.3390/su13116448