Assessment and optimization of an integrated energy system with electrolysis and fuel cells for electricity, cooling and hydrogen production using various optimization techniques

https://doi.org/10.1016/j.ijhydene.2019.06.127Get rights and content

Highlights

  • Proposed a novel CCHP system with PEMFC and energy storage.

  • Applied a dynamic model of thermal storage system to proposed CCHP.

  • Show the influence of different interest rates on Pareto frontier.

  • Applied different evolutionary algorithms to a proposed CCHP system.

  • Comparison of Pareto frontier of different evolutionary algorithms.

Abstract

In this research study, a novel integrated solar based combined, cooling, heating and, power (CCHP) is proposed consisting of Parabolic trough solar collectors (PTSC) field, a dual-tank molten salt heat storage, an Organic Rankine Cycle (ORC), a Proton exchange membrane fuel cell (PEMFC), a Proton exchange membrane electrolyzer (PEME), and a single effect Li/Br water absorption chiller. Thermodynamics and economic relations are used to analyze the proposed CCHP system. The mean of Tehran solar radiation as well as each portion of solar radiation during 24 h in winter is obtained from TRNSYS software to be used in PTSC calculations. A dynamic model of the thermal storage unit is assessed for proposed CCHP system under three different conditions (i.e., without thermal energy storage (TES), with TES and with TES + PEMFC). The results demonstrate that PEMFC has the ability to improve the power output by 10% during the night and 3% at sunny hours while by using TES alone, the overnight power generation is 86% of the power generation during the sunny hours. The optimum operating condition is determined via the NSGA-II algorithm with regards to exergy efficiency and total cost rate as objective functions where the optimum values are 0.058 ($/s) and 80%, respectively. The result of single objective optimization is 0.044 ($/s) for the economic objective in which the exergy efficiency is at its lowest value (57.7%). In addition, results indicate that the amount of single objective optimization based on exergetic objective is 88% in which the total cost rate is at its highest value (0.086 $/s). The scattered distribution of design parameters and the decision variables trend are investigated. In the next step, five different evolutionary algorithms namely NSGA-II, GDE3, IBEA, SMPSO, and SPEA2 are applied, and their Pareto frontiers are compared with each other.

Introduction

An increase in daily energy use and also a growing trend of human population has led human societies to search for more efficient power plants with less environmental effects and better sustainability. Combined cooling, heating and power generation (CCHP) plant which is also called trigeneration system, can benefit human society to achieve this goal. Renewable-based CCHP systems have attracted more attentions during the last decades. Amon them, solar energy not only can run the CCHP plants with zero emission but also it is free and easy to access. There are several published papers about the importance of CCHP systems for performance improvement and emission reduction. Ahmadi et al. [1] studied the environmental impact assessment of trigeneration systems. They considered a gas turbine based trigeneneration system with a single effect Li/Br water absorption chiller to produce cooling. They compared the emissions of the trigeneration system with a single gas turbine power generation system and the results showed that the emission reduces for about 40% from single generation to trigeneration. Abbasi et al. [2] studied the energy, exergy, and economic evaluations of a CCHP system by using internal combustion engines and gas turbines as prime movers. In their study, three types of prime movers namely gas engine, diesel engine, and gas turbine were considered and studied separately and simultaneously at six different scenarios and the appropriate scenario ha sbeen proposed for the CCHP system. The results show that the CCHP system under the electricity supply strategy with the simultaneous combination of two prime movers has significant advantages over one of them. Wang et al. [3] studied energy and exergy analyses of an integrated CCHP system with biomass air gasification. Researchers have also gone beyond energy, exergy and exergo-economic analyses of CCHP systems. Some have applied advanced exergy analysis [4], [5], [6], [7] and some applied optimization. In the following part we will try to focus on researches about modeling and development of solar based CCHP systems.

One of the effective methods to collect the solar heat is parabolic trough solar collectors (PTSC) units which attract a lot of attentions in recent decades. Al-Sulaiman [8] investigated the exergy efficiency of PTSC with combined steam Rankine cycle and organic Rankine cycle. Seven different refrigerants are examined for the organic Rankine cycle. The results show that R134a has the best exergy efficiency of 26%. Toghyani et al. [9] proposed an integrated Rankine power cycle whit PTSC. They also investigated four different nano-fluids namely CuO, SiO2, TiO2, and Al2O3. Their results show that the CuO/oil has the best performance in exergy point of view. Desai and Bandyopadhyay [10] studied the turbine inlet pressure and turbine inlet temperature effect on integrated Rankine power cycle whit PTSC. Borunda et al. [11] proposed a novel configuration of PTSC and ORC since the useful energy is directly used to charge the thermal storage unit and feed the power block. Yuksel [12] investigated an ORC integrated with PTSC for producing hydrogen as a clean fuel. The proposed integrated system is consisting of a modified ORC, a single effect absorption cooling system, a (proton exchange membrane) PEM electrolyzer and a parabolic trough collector. The results indicate that solar radiation has the most influence on the system exergy efficiency and hydrogen production rate. The exergy efficiency increases from 58% to 64% when solar radiation increases from 400 (W/mˆ2) to 1000 (W/mˆ2). Zare and Moalemian [13] proposed a novel integrated energy system which is consist of Kalian cycle and PTSC. Their results show that that the total exergy efficiency of this novel integrated energy system is around 14%. Their economic analysis indicates that it is more beneficial to increase the collector units per row instead of increasing the number of parallel rows. H. Zhai et al. [14] studied a small scale CCHP. They found that the PTSC exergy and energy loss is 70.4% and 36.2%, respectively. Their economic analysis based on cost and payback period shows that the payback period for their proposed energy system is 18 years under 2008 energy price condition. Their sensitivity analysis indicates that if the energy price increases by 50% or the interest rate decrease to 3%, the payback period will be decreased to less than ten years. In the present research study PTSC is selected because of tit higher temperature than PV and also ORC is utilized for power generation. The waste heat of the ORC system is regenerated to produce hydrogen and cooling load.

Hydrogen has been considered as a clean fuel since a few years ago. Its high heating value along with carbon free nature has made it promising for sustainable development [15]. As a result, in this research paper, a proton exchange membrane electrolyzer is employed to produce hydrogen. A lot of investigations have been carried out to produce hydrogen utilizing solar energy [16], [17], [18]. Nami et al. [19] proposed an integrated energy system which utilizes the waste heat to produce hydrogen. They employed ORC and PEM electrolyzer to achieve this goal. Their results indicate that the exergy efficiency, hydrogen production rate and sustainability index of the proposed system under optimized condition are 49.21%, 56.2 kg/h and 1.972, respectively. Safari and Dincer [20] investigated an integrated energy system consists of PEM electrolyzer, multi-effect desalination system and a combined Brayton and ORC power generation unit. iesExergy efficiency of the PEM electrolyzer and overall multi-generation system were obtained as 61% and 40%, respectively. Ferrero and Santarelli [21] developed a 2D finite element model of a high-pressure PEM water electrolyzer and validate it with experimental data. The results indicate that employing multi-junction cell improve the system efficiency in comparison to separated photovoltaic cell. Omar and Altinisik [22] proposed a PEM electrolyzer unit integrated with hybrid solar collector. They concluded that the pressure dose not have the significant influence on hydrogen and oxygen production. Ghribi et al. [23] investigated a PEM electrolyzer integrated with PV. The results indicate that the annual hydrogen production at the best solar zone can be change from 20 to 29 (mˆ3). Koponen et al. [24] studied a PEM electrolyzer unit integrated with PV panels. Their results demonstrate that when the outlet pressure of hydrogen raised from 2.0 MPa to 4.0 MPa, the stack specific energy consumption rises by 0.2 (kWh/Nmˆ3). Saadi et al. [25] investigated the hydrogen production via PV panel in Algeria. Their results demonstrate that the rate of hydrogen production would be 0.02 mol/s, if the current density is 50 A.

Abutayeh [26] proposed a dynamic model for dual heat storage tanks during a day and showed the influence of the heat storage tank on the power generation. Ya-Ling He et al. [27] recommended storage tanks molten salt volumes for spring equinox, summer solstice, autumnal equinox and winter solstice 100 m3, 150 m3, 50 m3,0 m3, respectively.

Fuel cells have been recognized as a reliable alternative to fossil fuels over the last few decades. They are a sort of energy conversion equipment which converts chemical energy into electrical energy, water and, heat without combustion. Proton exchange membrane fuel cell (PEMFC) is one of the most popular fuel cells because of some key advantages such as high power density, fast response ability, quickly start and low operating temperature. Hwang et al. [28], [29] studied a heat recovery unit by employing PEMFC in order to produce hot water and electricity simultaneously. Their energy system maximum efficiency was 81%. Briguglio et al. [30] investigated a 5 kW PEMFC integrated with a hybrid system to recover the waste heat with employing heat exchanger in cathode outlet. The results indicate that the overall efficiency of the system increased up to 85%, if the heat exchanger works at nominal power. Shabani and Andrews [31] studied a PEMFC integrated with solar-hydrogen system to improve total energy efficiency. The recovered heat from the PEMFC can be used for fuel reforming goals. Zhang et al. [32] proposed an integrated system which is consisting of PEMFC, refrigeration cycle to employed the waste heat of PEMFC for refrigeration purposes. Forde et al. [33] studied a PEMFC integrated with metal hydride storage unit. They use the PEMFC waste heat to accelerate hydrogen release from a metal hydride storage. Zhao et al. [34] proposed an energy system which use PEMFC waste heat to run an ORC. The results show that the electrical efficiency of the combined cycle is improved by 5% in comparison with single PEMFC without ORC. As it is mentioned, this study tries to consider a renewable-based energy system to produce electricity, heating, cooling and hydrogen. In the present research study, comprehensive thermodynamic modeling of a solar based CCHP system is initially carried out and the model is validated with numerical and experimental data. After the modeling step, exergy as potential tool is appllied in order to determine the loses. In addition, several evolutionary algorithm is employed for multi-objective optimization to assess each algorithm performance. This research study aims to determine the optimum operation condition and their optimum design parameters. To better highlight the novelties of this work, followings are the major contributions of this research study.

  • To comprehensively model a newly developed renewable-based CCHP system consisting of solar collectors, an electrolyzer, a fuel cell and ORC system.

  • To assess a dynamic model of TES unit and influence of PEM fuel cell stack on it

  • To see the effect of PEM fuel cell stack on proposed energy system efficiency

  • To apply various multi-objective optimization technique to a CCHP system.

  • To determine the optimal design parameters of the CCHP system and show the optimized values on the Pareto curve.

  • To assess each multi-objective optimization technique and compare their performance

  • To investigate the techno-economic sensitivity of the Pareto frontier

Section snippets

System description and assumption

The schematic of the proposed system is illustrated in Fig. 1. This integrated system consists of a PEM electrolyzer, a PEM fuel cell, a single effect Li/Br water absorption chiller, parabolic through solar collectors (PTSCs), a heat storage unit. PTSC is selected because of its higher temperature operation in comparison with non-concentrated solar collector such as PV panels. PV or other non-concentrated collector cannot provide sufficient energy for proposed CCHP because of their low

Parabolic trough solar collectors

The PTSC model is described in this subsection. The present model is based on the relation which is proposed in Refs. [37], [38], and [39]. These relations are confirmed with Dudley's et al. experimental data [40]. The useful energy gained by PTSC is given by Ref. [39]:Q˙u=m˙r(Cr.oTr.oCr.iTr.i)Where Q˙u indicates the useful power the useful power and is the amount of mass flow rate which is circulated in the receiver pipes. Subscribes r.iando represent the receiver, inlet and outlet

Exergoeconomic analysis

Exergoeconomic analysis helps to evaluate the performance of the system with economics point of view. It can assess the purchase cost of each component or the total cost rate of energy systems. For this purpose, we consider each part as a control volume. The cost balance equation can be described as [51]:C˙out.k+C˙w.k=C˙in.k+C˙q.k+Z˙k.PYC˙=cEx˙Where c and Ex˙ are the stream's energy related cost and the overall exergy rate, respectively and also,C˙w.k and Z˙k.PY indicate the power cost rate

Optimization

We always want to have an energy system which has higher efficiency and lower cost. Optimization helps us to achieve this goal. A lot of research has been done based on NSGA-II. In this research paper, several evolutionary algorithms (EA) such as NSGA-II, GDE3, IBEA, SMPSO, and SPEA2 is investigated. Each of them is described as below:

  • NSGA-II: NSGA-II is one of the most popular EAs which is widely used. It has three special characteristics namely fast non-dominated sorting procedure, a simple

TES performance

A thermal energy storage unit is applied to dispel unconformity between the power generation rate and energy demand. Also it acts as a buffer between the PTSC field and CCHP subsystems. In this research study, the dual-tank molten salt heat storage is considered. This subsystem also benefits from an auxiliary heater which operates at the situation which molten salt cannot provide the required heat. Solar based integrated energy systems are directly influenced by solar irradiation; meanwhile,

Conclusion

In this research study, a novel solar integrated energy system is proposed. The proposed CCHP consists of PTSCs, a TES, an ORC, a PEME, a PEMFC and a single effect Li–Br water absorption chiller. The thermodynamic and economic model of the proposed CCHP is represented in sections Energy analyses and sections Exergoeconomic analysis, respectively. The mean of Tehran solar radiation during the winter in 24 h is obtained from TRNSYS software and also, each portion of solar radiation during 24 h is

References (63)

  • H. Zhai et al.

    Energy and exergy analyses on a novel hybrid solar heating, cooling and power generation system for remote areas

    Appl Energy

    (2009)
  • P. Ahmadi et al.

    Comparative life cycle assessment of hydrogen fuel cell passenger vehicles in different Canadian provinces

    Int J Hydrogen Energy

    (2015)
  • A.H. Keshavarzzadeh et al.

    Multi-objective techno-economic optimization of a solar based integrated energy system using various optimization methods

    Energy Convers Manag

    (2019)
  • A. Prakash

    “Solar energy materials and solar cells in 2 S 3/CuS nanosheet composite : an excellent visible light photocatalyst for H 2 production from H 2 S

    (2018)
  • J.K. Sheu et al.

    Solar Energy Materials & Solar Cells InGaN-based epitaxial fi lms as photoelectrodes for hydrogen generation through water photoelectrolysis and CO 2 reduction to formic acid

    Sol Energy Mater Sol Cells

    (2017)
  • H. Nami et al.

    Utilization of waste heat from GTMHR for hydrogen generation via combination of organic rankine cycles and PEM electrolysis

    Energy Convers Manag

    (2016)
  • F. Safari et al.

    Development and analysis of a novel biomass- based integrated system for multigeneration with hydrogen production

    Int J Hydrogen Energy

    (2019)
  • D. Ferrero et al.

    Investigation of a novel concept for hydrogen production by PEM water electrolysis integrated with multi-junction solar cells

    Energy Convers Manag

    (2017)
  • M.A. Omar et al.

    Simulation of hydrogen production system with hybrid solar collector

    Int J Hydrogen Energy

    (2016)
  • D. Ghribi et al.

    Study of hydrogen production system by using PV solar energy and PEM electrolyser in Algeria

    Int J Hydrogen Energy

    (2013)
  • A. Saadi et al.

    Hydrogen production horizon using solar energy in Biskra, Algeria

    Int J Hydrogen Energy

    (2016)
  • Y. He et al.

    Simulation of the parabolic trough solar energy generation system with organic rankine cycle

    Appl Energy

    (2012)
  • J.J. Hwang et al.
    (2010)
  • N. Briguglio et al.

    Evaluation of a low temperature fuel cell system for residential CHP

    Int J Hydrogen Energy

    (2011)
  • B. Shabani et al.

    An experimental investigation of a PEM fuel cell to supply both heat and power in a solar-hydrogen RAPS system

    Int J Hydrogen Energy

    (2011)
  • T. Førde et al.
    (2009)
  • A. Baghernejad et al.

    Exergoeconomic analysis and optimization of an integrated solar combined cycle system (ISCCS) using genetic algorithm

    Energy Convers Manag

    (2011)
  • F.A. Al-Sulaiman et al.

    Performance assessment of a novel system using parabolic trough solar collectors for combined cooling, heating, and power production

    Renew Energy

    (2012)
  • S.C. Kaushik et al.

    Finite time thermodynamic evaluation of irreversible Ericsson and Stirling heat engines

    Energy Convers Manag

    (2001)
  • P. Ahmadi et al.

    Energy and exergy analyses of hydrogen production via solar-boosted ocean thermal energy conversion and PEM electrolysis

    Int J Hydrogen Energy

    (2013)
  • F. Safari et al.

    Assessment and optimization of an integrated wind power system for hydrogen and methane production

    Energy Convers Manag

    (2018)
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